text:
Conservation Physiology
Open Access journal
ISSN (Online) 2051-1434
Published by Oxford University Press (OUP) [310 journals]
- Physiology in conservation translocations
Authors: Tarszisz, E; Dickman, C. R, Munn, A. J.
Pages: cou054 - cou054
Abstract: Conservation translocations aim to restore species to their indigenous ranges, protect populations from threats and/or reinstate ecosystem functions. They are particularly important for the conservation and management of rare and threatened species. Despite tremendous efforts and advancement in recent years, animal conservation translocations generally have variable success, and the reasons for this are often uncertain. We suggest that when little is known about the physiology and wellbeing of individuals either before or after release, it will be difficult to determine their likelihood of survival, and this could limit advancements in the science of translocations for conservation. In this regard, we argue that physiology offers novel approaches that could substantially improve translocations and associated practices. As a discipline, it is apparent that physiology may be undervalued, perhaps because of the invasive nature of some physiological measurement techniques (e.g. sampling body fluids, surgical implantation). We examined 232 publications that dealt with translocations of terrestrial vertebrates and aquatic mammals and, defining 'success' as high or low, determined how many of these studies explicitly incorporated physiological aspects into their protocols and monitoring. From this review, it is apparent that physiological evaluation before and after animal releases could progress and improve translocation/reintroduction successes. We propose a suite of physiological measures, in addition to animal health indices, for assisting conservation translocations over the short term and also for longer term post-release monitoring. Perhaps most importantly, we argue that the incorporation of physiological assessments of animals at all stages of translocation can have important welfare implications by helping to reduce the total number of animals used. Physiological indicators can also help to refine conservation translocation methods. These approaches fall under a new paradigm that we term 'translocation physiology' and represent an important sub-discipline within conservation physiology generally.
PubDate: 2014-12-17T00:29:39-08:00
DOI: 10.1093/conphys/cou054|hwp:master-id:conphys;cou054
Issue No: Vol. 2, No. 1 (2014)
- The influence of water temperature and accelerometer-determined fight
intensity on physiological stress and reflex impairment of angled
largemouth bass
Authors: Brownscombe, J. W; Marchand, K, Tisshaw, K, Fewster, V, Groff, O, Pichette, M, Seed, M, Gutowsky, L. F. G, Wilson, A. D. M, Cooke, S. J.
Pages: cou057 - cou057
Abstract: Release of fish captured by recreational anglers is a common practice due to angler conservation ethics or compliance with fisheries regulations. As such, there is a need to understand the factors that influence mortality and sub-lethal impairments to ensure that catch-and-release angling is a sustainable practice. Longer angling times generally contribute to increased stress and mortality in fish such that reducing these times putatively reduces stress and improves survival. However, the relative importance of fight intensity (rather than simply duration) on fish condition is poorly understood. The objective of this research was to examine the effects of fight intensity on physiological stress and reflex impairment of largemouth bass (Micropterus salmoides). The largemouth bass were angled using conventional recreational fishing gear in May (water temperature ~12°C) and June (~22°C) of 2014 in Lake Opinicon, Ontario, Canada. Fight intensity was quantified using tri-axial accelerometer loggers mounted on the tips of fishing rods. Upon capture, reflex impairment measures were assessed, and fish were held for 1 h prior to blood sampling for measurement of physiological stress (blood glucose and lactate concentrations and pH). Physiological stress values showed a negative trend with fight duration and total fight intensity, but a positive trend with average fight intensity. Water temperature emerged as the most important predictor of the stress response in largemouth bass, while fight duration and intensity were not strong predictors. Reflex impairment was minimal, but higher reflex impairment scores were associated with elevated blood glucose. Overall, the findings of this study suggest that angling for largemouth bass at colder temperatures (20°C). Based on our findings, we conclude that fight intensity is likely not to be a major driver of physiological stress in this species using typical largemouth bass angling gear, owing to the relatively short fight times (i.e.
PubDate: 2014-12-08T02:10:09-08:00
DOI: 10.1093/conphys/cou057|hwp:master-id:conphys;cou057
Issue No: Vol. 2, No. 1 (2014)
- Investigation into the characteristics, triggers and mechanism of apnoea
and bradycardia in the anaesthetized platypus (Ornithorhynchus anatinus)
Authors: Macgregor, J. W; Holyoake, C, Fleming, P. A, Robertson, I. D, Connolly, J. H, Warren, K. S.
Pages: cou053 - cou053
Abstract: Health and conservation research on platypuses (Ornithorhynchus anatinus) may require anaesthesia to reduce stress and the risk of injury to both the animal and the researcher, as well as to facilitate examination and sample collection. Platypus anaesthesia can be difficult to manage, with reports of periods of apnoea and bradycardia described. This study investigated the conditions around sudden-onset apnoea and bradycardia in 163 field-anaesthetized platypuses as part of a health study. Anaesthesia was induced and maintained using isoflurane delivered in oxygen by face mask. Sudden-onset apnoea and bradycardia was observed in 19% of platypuses, occurring either at induction of anaesthesia, during recovery, or both. At induction, occurrence was more often recorded for adults (P = 0.19) and was correlated with low body temperature (P
PubDate: 2014-12-05T00:03:33-08:00
DOI: 10.1093/conphys/cou053|hwp:master-id:conphys;cou053
Issue No: Vol. 2, No. 1 (2014)
- Efficacy of a sensory deterrent and pipe modifications in decreasing
entrainment of juvenile green sturgeon (Acipenser medirostris) at
unscreened water diversions
Authors: Poletto, J. B; Cocherell, D. E, Mussen, T. D, Ercan, A, Bandeh, H, Levent Kavvas, M, Cech, J. J, Fangue, N. A.
Pages: cou056 - cou056
Abstract: Water projects designed to extract fresh water for local urban, industrial and agricultural use throughout rivers and estuaries worldwide have contributed to the fragmentation and degradation of suitable habitat for native fishes. The number of water diversions located throughout the Sacramento–San Joaquin watershed in California's Central Valley exceeds 3300, and the majority of these are unscreened. Many anadromous fish species are susceptible to entrainment into these diversions, potentially impacting population numbers. In the laboratory, juvenile green sturgeon (Acipenser medirostris) have been shown to have high entrainment rates into unscreened diversions compared with those of other native California fish species, which may act as a significant source of mortality for this already-threatened species. Therefore, we tested the efficacy of a sensory deterrent (strobe light) and two structural pipe modifications (terminal pipe plate and upturned pipe configuration) in decreasing the entrainment of juvenile green sturgeon (mean mass ± SEM = 162.9 ± 4.0 g; mean fork length = 39.4 ± 0.3 cm) in a large (>500 kl) outdoor flume fitted with a water-diversion pipe 0.46 m in diameter. While the presence of the strobe light did not affect fish entrainment rates, the terminal pipe plate and upturned pipe modifications significantly decreased the proportion of fish entrained out of the total number tested relative to control conditions (0.13 ± 0.02 and 0.03 ± 0.02 vs. 0.44 ± 0.04, respectively). These data suggest that sensory deterrents using visual stimuli are not an effective means to reduce diversion pipe interactions for green sturgeon, but that structural alterations to diversions can successfully reduce entrainment for this species. Our results are informative for the development of effective management strategies to mitigate the impacts of water diversions on sturgeon populations and suggest that effective restoration strategies that balance agricultural needs with conservation programmes are possible.
PubDate: 2014-12-05T00:03:33-08:00
DOI: 10.1093/conphys/cou056|hwp:master-id:conphys;cou056
Issue No: Vol. 2, No. 1 (2014)
- Validation and use of hair cortisol as a measure of chronic stress in
eastern chipmunks (Tamias striatus)
Authors: Mastromonaco, G. F; Gunn, K, McCurdy-Adams, H, Edwards, D. B, Schulte-Hostedde, A. I.
Pages: cou055 - cou055
Abstract: Stress levels of individuals are documented using glucocorticoid concentrations (including cortisol) in blood, saliva, urine or faeces, which provide information about stress hormones during a short period of time (minutes to days). In mammals, use of hair cortisol analysis allows for the assessment of prolonged stress over weeks and months and provides information on chronic stress levels without bias associated with handling. Here, we validate hair cortisol analysis in wild rodents using exogenous adrenocorticotrophic hormone (ACTH challenge) and apply the technique to evaluate stress in eastern chipmunks inhabiting logged and natural sites. Chipmunks were subjected to a mark–recapture study and injected weekly with ACTH (Synacthen Depot) or saline, with hair being collected at the conclusion of the challenge. Subsequently, faecal and hair samples were collected from chipmunks occupying logged and natural sites to assess the utility of hair cortisol in comparison with faecal cortisol metabolites. Following extraction, cortisol concentrations were quantified in hair and faecal extracts by enzyme immunoassay. Hair cortisol concentrations were significantly elevated in samples from ACTH-injected chipmunks compared with saline-injected control animals (five times higher). Chipmunks inhabiting logged sites had increased faecal cortisol metabolite concentrations compared with those in natural sites, but no differences were observed in hair cortisol concentrations. Faecal cortisol metabolite levels were positively correlated with hair cortisol levels in chipmunks. Hair cortisol levels reflect changes in circulating cortisol levels and can be used to evaluate the adrenal stress response, and thus stress, in natural populations. Nonetheless, because of the differences in the temporal scale of stress that hair and faeces represent, we caution the use of hair cortisol for detecting differences in physiological stress when comparing individuals within populations and suggest that it is best suited to examining population-level differences.
PubDate: 2014-12-05T00:03:33-08:00
DOI: 10.1093/conphys/cou055|hwp:master-id:conphys;cou055
Issue No: Vol. 2, No. 1 (2014)
- Chronic exposure to a low dose of ingested petroleum disrupts
corticosterone receptor signalling in a tissue-specific manner in the
house sparrow (Passer domesticus)
Authors: Lattin, C. R; Romero, L. M.
Pages: cou058 - cou058
Abstract: Stress-induced concentrations of glucocorticoid hormones (including corticosterone, CORT) can be suppressed by chronic exposure to a low dose of ingested petroleum. However, endocrine-disrupting chemicals could interfere with CORT signalling beyond the disruption of hormone titres, including effects on receptors in different target tissues. In this study, we examined the effects of 6 weeks of exposure to a petroleum-laced diet (1% oil weight:food weight) on tissue mass and intracellular CORT receptors in liver, fat, muscle and kidney (metabolic tissues), spleen (an immune tissue) and testes (a reproductive tissue). In the laboratory, male house sparrows were fed either a 1% weathered crude oil (n = 12) or a control diet (n = 12); glucocorticoid receptors and mineralocorticoid receptors were quantified using radioligand binding assays. In oil-exposed birds, glucocorticoid receptors were lower in one metabolic tissue (liver), higher in another metabolic tissue (fat) and unchanged in four other tissues (kidney, muscle, spleen and testes) compared with control birds. We saw no differences in mineralocorticoid receptors between groups. We also saw a trend towards reduced mass of the testes in oil-exposed birds compared with controls, but no differences in fat, kidney, liver, muscle or spleen mass between the two groups. This is the first study to examine the effects of petroleum on CORT receptor density in more than one or two target tissues. Given that a chronic low dose of ingested petroleum can affect stress-induced CORT titres as well as receptor density, this demonstrates that oil can act at multiple levels to disrupt an animal's response to environmental stressors. This also highlights the potential usefulness of the stress response as a bioindicator of chronic crude oil exposure.
PubDate: 2014-12-03T17:16:25-08:00
DOI: 10.1093/conphys/cou058|hwp:master-id:conphys;cou058
Issue No: Vol. 2, No. 1 (2014)
- Contemporary reliance on bicarbonate acquisition predicts increased growth
of seagrass Amphibolis antarctica in a high-CO2 world
Authors: Burnell, O. W; Connell, S. D, Irving, A. D, Watling, J. R, Russell, B. D.
Pages: cou052 - cou052
Abstract: Rising atmospheric CO2 is increasing the availability of dissolved CO2 in the ocean relative to HCO3 –. Currently, many marine primary producers use HCO3 – for photosynthesis, but this is energetically costly. Increasing passive CO2 uptake relative to HCO3 – pathways could provide energy savings, leading to increased productivity and growth of marine plants. Inorganic carbon-uptake mechanisms in the seagrass Amphibolis antarctica were determined using the carbonic anhydrase inhibitor acetazolamide (AZ) and the buffer tris(hydroxymethyl)aminomethane (TRIS). Amphibolis antarctica seedlings were also maintained in current and forecasted CO2 concentrations to measure their physiology and growth. Photosynthesis of A. antarctica was significantly reduced by AZ and TRIS, indicating utilization of HCO3 –-uptake mechanisms. When acclimated plants were switched between CO2 treatments, the photosynthetic rate was dependent on measurement conditions but not growth conditions, indicating a dynamic response to changes in dissolved CO2 concentration, rather than lasting effects of acclimation. At forecast CO2 concentrations, seedlings had a greater maximum electron transport rate (1.4-fold), photosynthesis (2.1-fold), below-ground biomass (1.7-fold) and increase in leaf number (2-fold) relative to plants in the current CO2 concentration. The greater increase in photosynthesis (measured as O2 production) compared with the electron transport rate at forecasted CO2 concentration suggests that photosynthetic efficiency increased, possibly due to a decrease in photorespiration. Thus, it appears that the photosynthesis and growth of seagrasses reliant on energetically costly HCO3 – acquisition, such as A. antarctica, might increase at forecasted CO2 concentrations. Greater growth might enhance the future prosperity and rehabilitation of these important habitat-forming plants, which have experienced declines of global significance.
PubDate: 2014-11-27T01:39:59-08:00
DOI: 10.1093/conphys/cou052|hwp:master-id:conphys;cou052
Issue No: Vol. 2, No. 1 (2014)
- Sequential ovulation and fertility of polyoestrus in American black bears
(Ursus americanus)
Authors: Himelright, B. M; Moore, J. M, Gonzales, R. L, Mendoza, A. V, Dye, P. S, Schuett, R. J, Durrant, B. S, Read, B. A, Spady, T. J.
Pages: cou051 - cou051
Abstract: American black bears (Ursus americanus) are seasonally polyoestrous and exhibit delayed implantation, which may allow equal and independent fertility of recurrent oestruses of a mating season. We postulated that the luteal inactivity during delayed implantation allows bears to have sequential ovulation during a polyoestrous mating season such that each oestrus of a polyoestrous female will have equivalent fertility, and pregnancy would not preclude subsequent ovulation and superfetation. Controlled mating experiments were conducted on semi-free-ranging female American black bears during three mating seasons, wherein females were bred by different male cohorts in each oestrus. Behavioural observation, vulva score ranking, genetic paternity analysis, gross morphology of ovaries and microscopic morphology of diapaused embryos were used to evaluate the fertility of each subsequent oestrus in polyoestrous females. Oestrus duration, number of successful mounts and median vulva scores were similar between first and subsequent oestruses of the season. Polyoestrus occurred in 81.3% of oestrous females, with a 9.7 ± 5.5 day (mean ± SD) inter-oestrous interval. Sequential ovulation was documented in three polyoestrous females, including one that possessed both a corpus haemorrhagicum and a developed corpus luteum. Among polyoestrous dams, four of nine embryos were conceived in the first oestrus and five of nine in the second oestrus. These results indicate that each oestrus of polyoestrous females is capable of fertility, even if the female is already pregnant from a prior oestrus. Although superfetation was not directly observed in the present study, our results strongly suggest the potential of superfetation in the American black bear and provide novel insight into the complex behavioural and physiological breeding mechanisms of bears. Given that most endangered bear species share similar reproductive traits with American black bears, captive breeding programmes could take advantage of superfetation by mating females with different males at each subsequent oestrus of the season in order to increase the genetic diversity of captive endangered bears.
PubDate: 2014-11-25T22:45:18-08:00
DOI: 10.1093/conphys/cou051|hwp:master-id:conphys;cou051
Issue No: Vol. 2, No. 1 (2014)
- The role thermal physiology plays in species invasion
Authors: Kelley; A. L.
Pages: cou045 - cou045
Abstract: The characterization of physiological phenotypes that may play a part in the establishment of non-native species can broaden our understanding about the ecology of species invasion. Here, an assessment was carried out by comparing the responses of invasive and native species to thermal stress. The goal was to identify physiological patterns that facilitate invasion success and to investigate whether these traits are widespread among invasive ectotherms. Four hypotheses were generated and tested using a review of the literature to determine whether they could be supported across taxonomically diverse invasive organisms. The four hypotheses are as follows: (i) broad geographical temperature tolerances (thermal width) confer a higher upper thermal tolerance threshold for invasive rather than native species; (ii) the upper thermal extreme experienced in nature is more highly correlated with upper thermal tolerance threshold for invasive vs. native animals; (iii) protein chaperone expression—a cellular mechanism that underlies an organism's thermal tolerance threshold—is greater in invasive organisms than in native ones; and (iv) acclimation to higher temperatures can promote a greater range of thermal tolerance for invasive compared with native species. Each hypothesis was supported by a meta-analysis of the invasive/thermal physiology literature, providing further evidence that physiology plays a substantial role in the establishment of invasive ectotherms.
PubDate: 2014-11-10T23:24:23-08:00
DOI: 10.1093/conphys/cou045|hwp:master-id:conphys;cou045
Issue No: Vol. 2, No. 1 (2014)
- Climate warming causes life-history evolution in a model for Atlantic cod
(Gadus morhua)
Authors: Holt, R. E; Jorgensen, C.
Pages: cou050 - cou050
Abstract: Climate change influences the marine environment, with ocean warming being the foremost driving factor governing changes in the physiology and ecology of fish. At the individual level, increasing temperature influences bioenergetics and numerous physiological and life-history processes, which have consequences for the population level and beyond. We provide a state-dependent energy allocation model that predicts temperature-induced adaptations for life histories and behaviour for the North-East Arctic stock (NEA) of Atlantic cod (Gadus morhua) in response to climate warming. The key constraint is temperature-dependent respiratory physiology, and the model includes a number of trade-offs that reflect key physiological and ecological processes. Dynamic programming is used to find an evolutionarily optimal strategy of foraging and energy allocation that maximizes expected lifetime reproductive output given constraints from physiology and ecology. The optimal strategy is then simulated in a population, where survival, foraging behaviour, growth, maturation and reproduction emerge. Using current forcing, the model reproduces patterns of growth, size-at-age, maturation, gonad production and natural mortality for NEA cod. The predicted climate responses are positive for this stock; under a 2°C warming, the model predicted increased growth rates and a larger asymptotic size. Maturation age was unaffected, but gonad weight was predicted to more than double. Predictions for a wider range of temperatures, from 2 to 7°C, show that temperature responses were gradual; fish were predicted to grow faster and increase reproductive investment at higher temperatures. An emergent pattern of higher risk acceptance and increased foraging behaviour was also predicted. Our results provide important insight into the effects of climate warming on NEA cod by revealing the underlying mechanisms and drivers of change. We show how temperature-induced adaptations of behaviour and several life-history traits are not only mediated by physiology but also by trade-offs with survival, which has consequences for conservation physiology.
PubDate: 2014-11-04T22:07:11-08:00
DOI: 10.1093/conphys/cou050|hwp:master-id:conphys;cou050
Issue No: Vol. 2, No. 1 (2014)
- Mother-egg stable isotope conversions and effects of lipid extraction and
ethanol preservation on loggerhead eggs
Authors: Kaufman, T. J; Pajuelo, M, Bjorndal, K. A, Bolten, A. B, Pfaller, J. B, Williams, K. L, Vander Zanden, H. B.
Pages: cou049 - cou049
Abstract: Carbon and nitrogen stable isotope (13C and 15N) analysis has been used to elucidate foraging and migration behaviours of endangered sea turtle populations. Isotopic analysis of tissue samples from nesting females can provide information about their foraging locations before reproduction. To determine whether loggerhead (Caretta caretta) eggs provide a good proxy for maternal isotope values, we addressed the following three objectives: (i) we evaluated isotopic effects of ethanol preservation and lipid extraction on yolk; (ii) we examined the isotopic offset between maternal epidermis and corresponding egg yolk and albumen tissue 13C and 15N values; and (iii) we assessed the accuracy of foraging ground assignment using egg yolk and albumen stable isotope values as a proxy for maternal epidermis. Epidermis (n = 61), albumen (n = 61) and yolk samples (n = 24) were collected in 2011 from nesting females at Wassaw Island, GA, USA. Subsamples from frozen and ethanol-preserved yolk samples were lipid extracted. Both lipid extraction and ethanol preservation significantly affected yolk 13C, while 15N values were not altered at a biologically relevant level. The mathematical corrections provided here allow for normalization of yolk 13C values with these treatments. Significant tissue conversion equations were found between 13C and 15N values of maternal epidermis and corresponding yolk and albumen. Finally, the consistency in assignment to a foraging area was high (up to 84%), indicating that these conversion equations can be used in future studies where stable isotopes are measured to determine female foraging behaviour and trophic relationships by assessing egg components. Loggerhead eggs can thus provide reliable isotopic information when samples from nesting females cannot be obtained.
PubDate: 2014-10-30T23:52:47-07:00
DOI: 10.1093/conphys/cou049|hwp:master-id:conphys;cou049
Issue No: Vol. 2, No. 1 (2014)
- Serial assessment of the physiological status of leatherback turtles
(Dermochelys coriacea) during direct capture events in the northwestern
Atlantic Ocean: comparison of post-capture and pre-release data
Authors: Innis, C. J; Merigo, C, Cavin, J. M, Hunt, K, Dodge, K. L, Lutcavage, M.
Pages: cou048 - cou048
Abstract: The physiological status of seven leatherback turtles (Dermochelys coriacea) was assessed at two time points during ecological research capture events in the northwestern Atlantic Ocean. Data were collected as soon as possible after securing each turtle onboard the capture vessel and again immediately prior to release. Measured parameters included sea surface temperature, body temperature, morphometric data, sex, heart rate, respiratory rate and various haematological and blood biochemical variables. Results indicated generally stable physiological status in comparison to previously published studies of this species. However, blood pH and blood potassium concentrations increased significantly between the two time points (P = 0.0018 and P = 0.0452, respectively). Turtles were affected by a mild initial acidosis (mean [SD] temperature-corrected pH = 7.29 [0.07]), and blood pH increased prior to release (mean [SD] = 7.39 [0.07]). Initial blood potassium concentrations were considered normal (mean [SD] = 4.2 [0.9] mmol/l), but turtles experienced a mild to moderate increase in blood potassium concentrations during the event (mean [SD] pre-release potassium = 5.9 [1.7] mmol/l, maximum = 8.5 mmol/l). While these data support the general safety of direct capture for study of this species, the observed changes in blood potassium concentrations are of potential concern due to possible adverse effects of hyperkalaemia on cardiac function. The results of this study highlight the importance of physiological monitoring during scientific capture events. The results are also likely to be relevant to unintentional leatherback capture events (e.g. fisheries interactions), when interactions may be more prolonged or extreme.
PubDate: 2014-10-30T23:52:47-07:00
DOI: 10.1093/conphys/cou048|hwp:master-id:conphys;cou048
Issue No: Vol. 2, No. 1 (2014)
- A product of its environment: the epaulette shark (Hemiscyllium ocellatum)
exhibits physiological tolerance to elevated environmental CO2
Authors: Heinrich, D. D. U; Rummer, J. L, Morash, A. J, Watson, S.-A, Simpfendorfer, C. A, Heupel, M. R, Munday, P. L.
Pages: cou047 - cou047
Abstract: Ocean acidification, resulting from increasing anthropogenic CO2 emissions, is predicted to affect the physiological performance of many marine species. Recent studies have shown substantial reductions in aerobic performance in some teleost fish species, but no change or even enhanced performance in others. Notably lacking, however, are studies on the effects of near-future CO2 conditions on larger meso and apex predators, such as elasmobranchs. The epaulette shark (Hemiscyllium ocellatum) lives on shallow coral reef flats and in lagoons, where it may frequently encounter short-term periods of environmental hypoxia and elevated CO2, especially during nocturnal low tides. Indeed, H. ocellatum is remarkably tolerant to short periods (hours) of hypoxia, and possibly hypercapnia, but nothing is known about its response to prolonged exposure. We exposed H. ocellatum individuals to control (390 µatm) or one of two near-future CO2 treatments (600 or 880 µatm) for a minimum of 60 days and then measured key aspects of their respiratory physiology, namely the resting oxygen consumption rate, which is used to estimate resting metabolic rate, and critical oxygen tension, a proxy for hypoxia sensitivity. Neither of these respiratory attributes was affected by the long-term exposure to elevated CO2. Furthermore, there was no change in citrate synthase activity, a cellular indicator of aerobic energy production. Plasma bicarbonate concentrations were significantly elevated in sharks exposed to 600 and 880 µatm CO2 treatments, indicating that acidosis was probably prevented by regulatory changes in acid–base relevant ions. Epaulette sharks may therefore possess adaptations that confer tolerance to CO2 levels projected to occur in the ocean by the end of this century. It remains uncertain whether other elasmobranchs, especially pelagic species that do not experience such diurnal fluctuations in their environment, will be equally tolerant.
PubDate: 2014-10-15T07:06:06-07:00
DOI: 10.1093/conphys/cou047|hwp:master-id:conphys;cou047
Issue No: Vol. 2, No. 1 (2014)
- Stress physiology of migrant birds during stopover in natural and
anthropogenic woodland habitats of the Northern Prairie region
Authors: Liu, M; Swanson, D. L.
Pages: cou046 - cou046
Abstract: Anthropogenic alterations of woodland habitat may influence stopover biology, which in turn could alter the stress physiology of migratory landbirds. Woodland stopover habitats are scarce in the Northern Prairie region of North America and consist of native riparian corridor woodlands (corridors) and smaller, more isolated woodlots of anthropogenic origin around farmsteads (woodlots). Corridor habitats have been greatly reduced since the time of European settlement, but woodlot habitats have appeared over this same time period. In this study, we compared stopover biology and stress physiology of migratory landbirds using natural and anthropogenic woodland habitats. We first tested for differences between birds in the two habitats for baseline corticosterone (CORTB) and the magnitude of the stress response for individual species, taxonomic families and foraging guilds. Plasma corticosterone increased significantly for all bird groups in both habitats following 30 min of restraint stress (CORT30), and neither CORTB nor the magnitude of the stress response (CORT30 – CORTB) differed significantly between birds in the two habitats. Secondly, because CORTB levels are often elevated and CORT secretion following a stressor is often suppressed for birds in poor body condition, we hypothesized that woodland migrants with higher fattening rates would show reduced CORTB and a robust stress response. We tested this hypothesis by assessing the relationships between plasma corticosterone and plasma metabolites associated with refuelling. We found that CORTB was negatively associated and the magnitude of the stress response positively associated with plasma triglycerides (an indicator of fat deposition), with opposite patterns for corticosterone and plasma β-hydroxybutyrate (an indicator of fat catabolism). These data suggest that both corridor and woodlot habitats serve as effective stopover habitat and that the reduction of corridor habitat and increased reliance on anthropogenic woodlots is not detrimental to the stress physiology of migrants in a region with limited woodland habitats.
PubDate: 2014-10-13T04:45:12-07:00
DOI: 10.1093/conphys/cou046|hwp:master-id:conphys;cou046
Issue No: Vol. 2, No. 1 (2014)
- Enzyme immunoassays as a method for quantifying hair reproductive hormones
in two felid species
Authors: Terwissen, C. V; Mastromonaco, G. F, Murray, D. L.
Pages: cou044 - cou044
Abstract: Non-invasive monitoring of wild felid reproductive states is important, given that many species reproduce poorly in captivity. Despite extensive work in faecal hormone analysis in felids, continued development of techniques is necessary, particularly with wild populations. In this study, our aims were as follows: (i) biochemical validation of enzyme immunoassays for estrogen, testosterone and progesterone in Canada lynx and domestic cat hair extracts; (ii) assessment of the use of hair reproductive hormones to differentiate between reproductive states (intact, estrus, pregnant and spayed/neutered), using domestic cats as a model; and (iii) assessment of the use of hair reproductive hormones to differentiate between age and sex, accounting for potential regional variability in wild lynx populations. Analysis of hair hormone levels showed prospective value in detecting pregnancy states, with pregnant domestic cats having higher levels of progesterone than spayed females. However, intact and pregnant cats did not differ in progesterone levels. Yet, two female domestic cats had higher levels of hair progesterone following a 38-day oral progestin treatment, perhaps providing a preliminary pharmacological validation of the method. Estrogen and testosterone did not differ statistically according to reproductive states of domestic cats, although intact males had higher levels of hair testosterone than neutered males. When we applied these techniques to lynx fur, we determined that hormone levels were not sufficiently precise to differentiate age classes. Hair reproductive hormone ratios differed between sexes, with the estrogen-to-progesterone ratio demonstrating the highest accuracy in differentiating males from females. Hair hormone levels differed regionally for wild lynx, indicating that spatial variability should be a consideration in wildlife hormone studies spanning large spatial scales. We conclude that use of hair hormone analysis by enzyme immunoassay may hold promise for differentiating sex in felids, but the technique will require further refinement and validation before it can be applied broadly and reliably.
PubDate: 2014-10-13T04:45:12-07:00
DOI: 10.1093/conphys/cou044|hwp:master-id:conphys;cou044
Issue No: Vol. 2, No. 1 (2014)
- Interpopulational variation in the cold tolerance of a broadly distributed
marine copepod
Authors: Wallace, G. T; Kim, T. L, Neufeld, C. J.
Pages: cou041 - cou041
Abstract: Latitudinal trends in cold tolerance have been observed in many terrestrial ectotherms, but few studies have investigated interpopulational variation in the cold physiology of marine invertebrates. Here, the intertidal copepod Tigriopus californicus was used as a model system to study how local adaptation influences the cold tolerance of a broadly distributed marine crustacean. Among five populations spanning 18° in latitude, the following three metrics were used to compare cold tolerance: the temperature of chill-coma onset, the chill-coma recovery time and post-freezing recovery. In comparison to copepods from warmer southern latitudes, animals from northern populations exhibited lower chill-coma onset temperatures, shorter chill-coma recovery times and faster post-freezing recovery rates. Importantly, all three metrics showed a consistent latitudinal trend, suggesting that any single metric could be used equivalently in future studies investigating latitudinal variation in cold tolerance. Our results agree with previous studies showing that populations within a single species can display strong local adaptation to spatially varying climatic conditions. Thus, accounting for local adaptation in bioclimate models will be useful for understanding how broadly distributed species like T. californicus will respond to anthropogenic climate change.
PubDate: 2014-10-07T00:16:11-07:00
DOI: 10.1093/conphys/cou041|hwp:master-id:conphys;cou041
Issue No: Vol. 2, No. 1 (2014)
- Evaluating physiological stress in Sumatran tigers (Panthera tigris ssp.
sumatrae) managed in Australian zoos
Authors: Parnell, T; Narayan, E. J, Magrath, M. J. L, Roe, S, Clark, G, Nicolson, V, Martin-Vegue, P, Mucci, A, Hero, J.-M.
Pages: cou038 - cou038
Abstract: Glucocorticoid quantification using non-invasive methods provides a powerful tool for assessing the health and welfare of wildlife in zoo-based programmes. In this study, we provide baseline data on faecal-based glucocorticoid (cortisol) monitoring of Sumatran tigers (Panthera tigris ssp. sumatrae) managed at the Melbourne Zoo in Victoria, Australia. We sampled five tigers daily for 60 days. Faecal cortisol metabolites (FCMs) in tiger faecal extracts were quantified using enzyme immunoassays that were successfully validated using parallelism and accuracy recovery checks. Two female tigers had significantly higher mean FCM levels than the two males and another female, suggesting that females may have higher FCM levels. A significant elevation was noted in the FCM levels for one female 2 days after she was darted and anaesthetized; however, the FCM levels returned to baseline levels within 3 days after the event. Comparative analysis of FCM levels of tigers sampled at Melbourne Zoo with tigers sampled earlier at two other Australian Zoos (Dreamworld Themepark and Australia Zoo) showed that FCM levels varied between zoos. Differences in the enclosure characteristics, timing of sampling, size and composition of groupings and training procedures could all contribute to this variation. Overall, we recommend the use of non-invasive sampling for the assessment of adrenocortical activity of felids managed in zoos in Australia and internationally in order to improve the welfare of these charismatic big cats.
PubDate: 2014-10-07T00:16:11-07:00
DOI: 10.1093/conphys/cou038|hwp:master-id:conphys;cou038
Issue No: Vol. 2, No. 1 (2014)
- Effects of visible implanted elastomer marking on physiological traits of
Authors: Antwis, R. E; Purcell, R, Walker, S. L, Fidgett, A. L, Preziosi, R. F.
Pages: cou042 - cou042
Abstract: Amphibians possess innate immune defences, including antimicrobial peptides and symbiotic bacterial communities, that can protect them from infectious diseases, including chytridiomycosis. On-going research is attempting to use amphibian symbiotic bacteria to develop probiotic treatments that can protect hosts from the causative agent of chytridiomycosis, the fungal pathogen Batrachochytrium dendrobatidis. Events that cause disruption of symbiotic bacterial communities or deplete peptide stores could increase the susceptibility of individuals to disease and may have implications for amphibians involved in probiotic trials or time course studies that investigate symbiotic bacterial communities. It has previously been shown that passive integrated transponder tagging of frogs causes a rapid (within 24 h) and major proliferation of micro-organisms on the skin. Here, we show that marking of red-eyed tree frogs (Agalychnis callidryas) with visible elastomer has no effect on adrenal response (represented by faecal glucocorticoid metabolite concentrations) or peptide production, although there was evidence of a slightly greater microbial abundance associated with the skin of marked frogs 2 weeks after tagging. The results indicate that visible elastomer may be a preferable marking technique to passive integrated transponder tagging, particularly in the context of probiotic trials or time course studies that investigate symbiotic bacterial communities. More work is required to determine the effects of different marking techniques on physiological responses of amphibians, whether these physiological responses are consistent across host species and whether such 'non-invasive' marking methods affect the susceptibility of amphibians to infectious pathogens, such as B. dendrobatidis.
PubDate: 2014-10-04T00:21:53-07:00
DOI: 10.1093/conphys/cou042|hwp:master-id:conphys;cou042
Issue No: Vol. 2, No. 1 (2014)
- Environmental factors and habitat use influence body condition of
individuals in a species at risk, the grizzly bear
Authors: Bourbonnais, M. L; Nelson, T. A, Cattet, M. R. L, Darimont, C. T, Stenhouse, G. B, Janz, D. M.
Pages: cou043 - cou043
Abstract: Metrics used to quantify the condition or physiological states of individuals provide proactive mechanisms for understanding population dynamics in the context of environmental factors. Our study examined how anthropogenic disturbance, habitat characteristics and hair cortisol concentrations interpreted as a sex-specific indicator of potential habitat net-energy demand affect the body condition of grizzly bears (n = 163) in a threatened population in Alberta, Canada. We quantified environmental variables by modelling spatial patterns of individual habitat use based on global positioning system telemetry data. After controlling for gender, age and capture effects, we assessed the influence of biological and environmental variables on body condition using linear mixed-effects models in an information theoretical approach. Our strongest model suggested that body condition was improved when patterns of habitat use included greater vegetation productivity, increased influence of forest harvest blocks and oil and gas well sites, and a higher percentage of regenerating and coniferous forest. However, body condition was negatively affected by habitat use in close proximity to roads and in areas where potential energetic demands were high. Poor body condition was also associated with increased selection of parks and protected areas and greater seasonal vegetation productivity. Adult females, females with cubs-of-year, juvenile females and juvenile males were in poorer body condition compared with adult males, suggesting that intra-specific competition and differences in habitat use based on gender and age may influence body condition dynamics. Habitat net-energy demand also tended to be higher in areas used by females which, combined with observed trends in body condition, could affect reproductive success in this threatened population. Our results highlight the importance of considering spatiotemporal variability in environmental factors and habitat use when assessing the body condition of individuals. Long-term and large-scale monitoring of the physiological state of individuals provides a more comprehensive approach to support management and conservation of species at risk.
PubDate: 2014-10-03T22:16:51-07:00
DOI: 10.1093/conphys/cou043|hwp:master-id:conphys;cou043
Issue No: Vol. 2, No. 1 (2014)
- Impacts of crowding, trawl duration and air exposure on the physiology of
stingarees (family: Urolophidae)
Authors: Heard, M; Van Rijn, J. A, Reina, R. D, Huveneers, C.
Pages: cou040 - cou040
Abstract: Research on physiological stress and post-capture mortality of threatened species caught as bycatch is critical for the management of fisheries. The present study used laboratory simulations to examine the physiological stress response of sparsely spotted stingarees (Urolophus paucimaculatus) subjected to one of four different trawl treatments, including two different trawl durations as well as ancillary stressors of either air exposure or crowding. Physiological indicators (plasma lactate, urea, potassium and glucose) and changes in white blood cell counts were measured from blood samples taken throughout a 48 h recovery period. Mortality was low throughout this study (15% overall) and occurred only after >48 h following air exposure, crowding and 3 h trawl simulations. Plasma lactate, glucose and urea concentrations were identified as potential indicators of physiological stress, while plasma potassium and white blood cell counts were too variable to identify changes that would be expected to have biological consequences for stingarees. The characterization of the temporal profiles of physiological indicators facilitates a more accurate assessment of secondary stressors by identifying the best timing to sample stingaree blood when investigating post-capture stress physiology. High levels of lactate, increasing glucose and depressed urea were all recorded in response to air exposure following trawling, indicating that this is the primary source of stress in stingarees caught in trawling operations. These findings highlight the importance of improving bycatch sorting procedures to reduce the time out of the water for trawl-caught stingarees.
PubDate: 2014-10-03T22:16:51-07:00
DOI: 10.1093/conphys/cou040|hwp:master-id:conphys;cou040
Issue No: Vol. 2, No. 1 (2014)
- A conceptual framework for the emerging discipline of conservation
Authors: Coristine, L. E; Robillard, C. M, Kerr, J. T, O'Connor, C. M, Lapointe, D, Cooke, S. J.
Pages: cou033 - cou033
Abstract: Current rates of biodiversity decline are unprecedented and largely attributed to anthropogenic influences. Given the scope and magnitude of conservation issues, policy and management interventions must maximize efficiency and efficacy. The relatively new field of conservation physiology reveals the physiological mechanisms associated with population declines, animal–environment relationships and population or species tolerance thresholds, particularly where these relate to anthropogenic factors that necessitate conservation action. We propose a framework that demonstrates an integrative approach between physiology, conservation and policy, where each can inform the design, conduct and implementation of the other. Each junction of the conservation physiology process has the capacity to foster dialogue that contributes to effective implementation, monitoring, assessment and evaluation. This approach enables effective evaluation and implementation of evidence-based conservation policy and management decisions through a process of ongoing refinement, but may require that scientists (from the disciplines of both physiology and conservation) and policy-makers bridge interdisciplinary knowledge gaps. Here, we outline a conceptual framework that can guide and lead developments in conservation physiology, as well as promote innovative research that fosters conservation-motivated policy.
PubDate: 2014-09-24T01:25:32-07:00
DOI: 10.1093/conphys/cou033|hwp:master-id:conphys;cou033
Issue No: Vol. 2, No. 1 (2014)
- Effects of natural environmental conditions on faecal glucocorticoid
metabolite concentrations in jaguars (Panthera onca) in Belize
Authors: Mesa-Cruz, J. B; Brown, J. L, Kelly, M. J.
Pages: cou039 - cou039
Abstract: In situ studies that rely on non-invasive faecal hormone monitoring are subject to problems due to potential changes in hormone concentrations in samples exposed to field conditions. In this study, we conducted an environmental validation for measurement of faecal glucocorticoid metabolites (FGMs) in jaguars (Panthera onca). We collected fresh faeces (e.g. no older than 8 h) from jaguars (six males and four females), housed at the Belize Zoo, and exposed them randomly to two environmental conditions: shade and sun. A control (first sub-sample) was immediately frozen, after which sub-samples were frozen daily over a 5 day period in both the dry and wet seasons. We quantified FGMs using a cortisol enzyme immunoassay (EIA) and a corticosterone radioimmunoassay (RIA), both capable of identifying relevant metabolites. Results indicated that FGMs assessed with the cortisol EIA were stable for 5 days during the dry season but for
PubDate: 2014-09-10T01:05:03-07:00
DOI: 10.1093/conphys/cou039|hwp:master-id:conphys;cou039
Issue No: Vol. 2, No. 1 (2014)
- Validation of the i-STAT system for the analysis of blood parameters in
Authors: Harter, T. S; Shartau, R. B, Brauner, C. J, Farrell, A. P.
Pages: cou037 - cou037
Abstract: Portable clinical analysers, such as the i-STAT system, are increasingly being used for blood analysis in animal ecology and physiology because of their portability and easy operation. Although originally conceived for clinical application and to replace robust but lengthy techniques, researchers have extended the use of the i-STAT system outside of humans and even to poikilothermic fish, with only limited validation. The present study analysed a range of blood parameters [pH, haematocrit (Hct), haemoglobin (Hb), HCO3 –, partial pressure of CO2 (PCO2), partial pressure of O2 (PO2), Hb saturation (sO2) and Na+ concentration] in a model teleost fish (rainbow trout, Oncorhynchus mykiss) using the i-STAT system (CG8+ cartridges) and established laboratory techniques. This methodological comparison was performed at two temperatures (10 and 20°C), two haematocrits (low and high) and three PCO2 levels (0.5, 1.0 and 1.5%). Our results indicate that pH was measured accurately with the i-STAT system over a physiological pH range and using the i-STAT temperature correction. Haematocrit was consistently underestimated by the i-STAT, while the measurements of Na+, PCO2, HCO3 – and PO2 were variably inaccurate over the range of values typically found in fish. The algorithm that the i-STAT uses to calculate sO2 did not yield meaningful results on rainbow trout blood. Application of conversion factors to correct i-STAT measurements is not recommended, due to significant effects of temperature, Hct and PCO2 on the measurement errors and complex interactions may exist. In conclusion, the i-STAT system can easily generate fast results from rainbow trout whole blood, but many are inaccurate values.
PubDate: 2014-09-03T20:01:42-07:00
DOI: 10.1093/conphys/cou037|hwp:master-id:conphys;cou037
Issue No: Vol. 2, No. 1 (2014)
- Elevational clines in the temperature dependence of insect performance and
implications for ecological responses to climate change
Authors: Buckley, L. B; Nufio, C. R.
Pages: cou035 - cou035
Abstract: To what extent is insect hopping and feeding performance, which constrains the ability to obtain and assimilate resources, thermally adapted along an elevation gradient' Does temperature dependence vary between populations and species and can differences account for individualistic responses to past climate change' We investigate these questions for three species of grasshoppers along a Rocky Mountain elevation gradient. All species and populations exhibit warm adaptation for consumption and digestion, with only modest inter- and intra-specific differences. Species differ substantially in the temperature of peak hopping performance. Low-elevation populations of the warm-adapted species exhibit the highest performance at high temperatures and the lowest performance at low temperatures. Developmental plasticity influences the temperature dependence of performance; grasshoppers reared at higher temperatures perform better at higher temperatures and possess broader thermal tolerance. We fitted thermal performance curves to examine whether performance shifts can account for changes in abundance between initial surveys in 1958–1960 and recent surveys since 2006. All species and populations are able to achieve greater feeding rates now. Estimated shifts in hopping performance vary between species and along the elevation gradient. The cool-adapted species has experienced declines in hopping performance, particularly at the lower elevation sites, while the warm-adapted species has experienced increases in performance concentrated at higher elevations. These estimated performance shifts broadly concur with observed abundance shifts. Performance metrics may have a greater potential to elucidate differential responses to climate change between populations and species than coarser and oft-used proxies, such as thermal tolerance. Assessing performance directly when temperature dependence varies between processes such as the acquisition and assimilation of energy may be essential to understanding population- and species-level impacts.
PubDate: 2014-08-25T01:36:35-07:00
DOI: 10.1093/conphys/cou035|hwp:master-id:conphys;cou035
Issue No: Vol. 2, No. 1 (2014)
- Larval green and white sturgeon swimming performance in relation to
water-diversion flows
Authors: Verhille, C. E; Poletto, J. B, Cocherell, D. E, DeCourten, B, Baird, S, Cech, J. J, Fangue, N. A.
Pages: cou031 - cou031
Abstract: Little is known of the swimming capacities of larval sturgeons, despite global population declines in many species due in part to fragmentation of their spawning and rearing habitats by man-made water-diversion structures. Larval green (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) inhabit the highly altered Sacramento–San Joaquin watershed, making them logical species to examine vulnerability to entrainment by altered water flows. The risk of larval sturgeon entrainment is influenced by the ontogeny of swimming capacity and dispersal timing and their interactions with water-diversion structure operations. Therefore, the aim of this study was to describe and compare the ontogeny and allometry of larval green and white sturgeon swimming capacities until completion of metamorphosis into juveniles. Despite the faster growth rates and eventual larger size of larval white sturgeon, green sturgeon critical swimming velocities remained consistently, though modestly, greater than those of white sturgeon throughout the larval life stage. Although behavioural interactions with water-diversion structures are also important considerations, regarding swimming capacity, Sacramento–San Joaquin sturgeons are most vulnerable to entrainment in February–May, when white sturgeon early larvae are in the middle Sacramento River, and April–May, when green sturgeon early larvae are in the upper river. Green sturgeon migrating downstream to the estuary and bays in October–November are also susceptible to entrainment due to their movements combined with seasonal declines in their swimming capacity. An additional inter-species comparison of the allometric relationship between critical swimming velocities and total length with several sturgeon species found throughout the world suggests a similar ontogeny of swimming capacity with growth. Therefore, although dispersal and behaviour differ among river systems and sturgeon species, similar recommendations are applicable for managers seeking to balance water demands with restoration and conservation of sturgeons worldwide.
PubDate: 2014-08-25T01:36:35-07:00
DOI: 10.1093/conphys/cou031|hwp:master-id:conphys;cou031
Issue No: Vol. 2, No. 1 (2014)
- Ontogenetic resource-use strategies in a rare long-lived cycad along
environmental gradients
Authors: Alvarez-Yepiz, J. C; Cueva, A, Dovčiak, M, Teece, M, Yepez, E. A.
Pages: cou034 - cou034
Abstract: Functional traits can drive plant responses to short- and long-term stressful conditions, with potential effects on species persistence in local habitats, changes in population size and structure, and potential species range shifts in changing environments. We investigated whether ecophysiological traits in a rare cycad vary along environmental gradients and with ontogeny to understand intra-specific resource-use variation (e.g. symbiotic nitrogen fixation, nitrogen- and water-use efficiency) and possible species adaptations for different environments. Environmental gradients were characterized with 14 soil and topographic variables. Nitrogen- and water-use efficiency improved with ontogeny (from seedling to juvenile and adult stages) but declined as soil fertility decreased with increasing elevation. Conversely, reliance on symbiotic nitrogen fixation increased with elevation and varied slightly with ontogeny. Improved water-use efficiency at lower elevation and nitrogen fixation at higher elevation may represent key functional strategies for maintaining the lower and upper altitudinal species range limits, especially in arid environments where stressful conditions are intensifying due to climatic and land-use changes. In addition to facilitation linked to the regeneration niche, improved resource-use efficiency linked to the adult niche may strongly influence cycad distribution and persistence in contemporary environments. A functional approach to conservation of rare or endangered plant species may be needed in order to target the most sensitive stages to changing environmental conditions and to better understand potential range shifts and adaptive responses to global land-use and climate changes.
PubDate: 2014-08-20T19:48:52-07:00
DOI: 10.1093/conphys/cou034|hwp:master-id:conphys;cou034
Issue No: Vol. 2, No. 1 (2014)
- A novel technique to measure chronic levels of corticosterone in turtles
living around a major roadway
Authors: Baxter-Gilbert, J. H; Riley, J. L, Mastromonaco, G. F, Litzgus, J. D, Lesbarreres, D.
Pages: cou036 - cou036
Abstract: Conservation biology integrates multiple disciplines to expand the ability to identify threats to populations and develop mitigation for these threats. Road ecology is a branch of conservation biology that examines interactions between wildlife and roadways. Although the direct threats of road mortality and habitat fragmentation posed by roads have received much attention, a clear understanding of the indirect physiological effects of roads on wildlife is lacking. Chronic physiological stress can lower immune function, affect reproductive rates and reduce life expectancy; thus, it has the potential to induce long-lasting effects on populations. Reptiles are globally in decline, and roads are known to have negative effects on reptile populations; however, it is unknown whether individual responses to roads and traffic result in chronic stress that creates an additional threat to population viability. We successfully extracted reliable measures of corticosterone (CORT), a known, commonly used biomarker for physiological stress, from claw trimmings from painted turtles (Chrysemys picta) captured at three study sites (road-impacted site, control site and validation site). Corticosterone levels in claws were evaluated as a measure of chronic stress in turtles because CORT is deposited during growth of the claw and could provide an opportunity to examine past long-term stress levels. While male turtles had higher CORT levels on average than females, there was no difference in the level of CORT between the road-impacted and control site, nor was there a relationship between CORT and turtle body condition. In validating a novel approach for non-invasive measurement of long-term CORT levels in a keratinized tissue in wild reptiles, our study provides a new avenue for research in the field of stress physiology.
PubDate: 2014-08-18T00:54:48-07:00
DOI: 10.1093/conphys/cou036|hwp:master-id:conphys;cou036
Issue No: Vol. 2, No. 1 (2014)
- Traffic noise causes physiological stress and impairs breeding migration
behaviour in frogs
Authors: Tennessen, J. B; Parks, S. E, Langkilde, T.
Pages: cou032 - cou032
Abstract: Human-generated noise has profoundly changed natural soundscapes in aquatic and terrestrial ecosystems, imposing novel pressures on ecological processes. Despite interest in identifying the ecological consequences of these altered soundscapes, little is known about the sublethal impacts on wildlife population health and individual fitness. We present evidence that noise induces a physiological stress response in an amphibian and impairs mate attraction in the natural environment. Traffic noise increased levels of a stress-relevant glucocorticoid hormone (corticosterone) in female wood frogs (Lithobates sylvaticus) and impaired female travel towards a male breeding chorus in the field, providing insight into the sublethal consequences of acoustic habitat loss. Given that prolonged elevated levels of corticosterone can have deleterious consequences on survival and reproduction and that impaired mate attraction can impact population persistence, our results suggest a novel pathway by which human activities may be imposing population-level impacts on globally declining amphibians.
PubDate: 2014-08-18T00:54:48-07:00
DOI: 10.1093/conphys/cou032|hwp:master-id:conphys;cou032
Issue No: Vol. 2, No. 1 (2014)
- Observable impairments predict mortality of captured and released sockeye
salmon at various temperatures
Authors: Gale, M. K; Hinch, S. G, Cooke, S. J, Donaldson, M. R, Eliason, E. J, Jeffries, K. M, Martins, E. G, Patterson, D. A.
Pages: cou029 - cou029
Abstract: Migrating adult sockeye salmon frequently encounter commercial and recreational fishing gear, from which they may be landed, escape or be intentionally released. In this experiment, migratory adult sockeye salmon were exposed to simulated capture–release in fresh water, including 3 min of exhaustive exercise and 60 s of air exposure at three ecologically relevant water temperatures (13, 16 and 19°C) to understand how thermal and capture–release stressors may interact to increase mortality risk. Water temperature and sex were the factors that best predicted 24 and 48 h survival, with females in the warmest temperature group experiencing the greatest mortality. Capture–release treatment including air exposure was associated with equilibrium loss and depressed ventilation rates at release; the probability of fish surviving for 24 h after simulated capture–release was >50% if the duration of equilibrium loss was 1 breath s–1. Higher haematocrit and plasma lactate as well as lower mean cell haemoglobin concentration and plasma sodium and chloride 30 min after simulated capture–release were also significant predictors of 24 h survival. Together, the results demonstrate that simple observations that are consistent with physiological disturbance can be used as predictors for post-release short-term survival for sockeye salmon. The markedly higher post-stressor mortality observed in females demonstrates that managers should consider sex-specific variation in response to different fisheries interactions, particularly in the face of climate change.
PubDate: 2014-08-14T04:50:47-07:00
DOI: 10.1093/conphys/cou029|hwp:master-id:conphys;cou029
Issue No: Vol. 2, No. 1 (2014)
- Baleen hormones: a novel tool for retrospective assessment of stress and
reproduction in bowhead whales (Balaena mysticetus)
Authors: Hunt, K. E; Stimmelmayr, R, George, C, Hanns, C, Suydam, R, Brower, H, Rolland, R. M.
Pages: cou030 - cou030
Abstract: Arctic marine mammals are facing increasing levels of many anthropogenic stressors. Novel tools are needed for assessment of stress physiology and potential impacts of these stressors on health, reproduction and survival. We have investigated baleen as a possible novel tissue type for retrospective assessment of stress and reproductive hormones. We found that pulverized baleen powder from bowhead whales (Balaena mysticetus) contained immunoreactive cortisol and progesterone that were detectable with commercially available enzyme immunoassay kits. Both assays passed parallelism and accuracy validations using baleen extracts. We analysed cortisol and progesterone at the base of the baleen plate (most recently grown baleen) from 16 bowhead whales of both sexes. For a subset of 11 whales, we also analysed older baleen from 10, 20 and 30 cm distal to the base of the baleen plate. Immunoreactive cortisol and progesterone were detectable in all baleen samples tested. In base samples, females had significantly higher concentrations of cortisol and progesterone compared with males. Cortisol concentrations in older baleen (10, 20 and 30 cm locations) were significantly lower than at the base and did not exhibit correlations with age-class or sex. Progesterone concentrations were significantly higher in females than in males at all baleen locations tested and were significantly higher in pregnant females than in non-pregnant females. Four of five mature females showed dramatic variation in progesterone concentrations at different locations along the baleen plate that may be indicative of previous pregnancies or luteal phases. In contrast, all males and all immature females had uniformly low progesterone. Baleen hormone analysis is a novel approach that, with further methodological development, may be useful for determining individual longitudinal profiles of reproductive cycles and stress responses.
PubDate: 2014-08-13T03:40:05-07:00
DOI: 10.1093/conphys/cou030|hwp:master-id:conphys;cou030
Issue No: Vol. 2, No. 1 (2014)
- Seasonal blood chemistry response of sub-tropical nearshore fishes to
climate change
Authors: Shultz, A. D; Zuckerman, Z. C, Stewart, H. A, Suski, C. D.
Pages: cou028 - cou028
Abstract: Climate change due to anthropogenic activity will continue to alter the chemistry of the oceans. Future climate scenarios indicate that sub-tropical oceans will become more acidic, and the temperature and salinity will increase relative to current conditions. A large portion of previous work has focused on how future climate scenarios may impact shell-forming organisms and coral reef fish, with little attention given to fish that inhabit nearshore habitats; few studies have examined multiple challenges concurrently. The purpose of this study was to quantify the blood-based physiological response of nearshore fishes to a suite of seawater conditions associated with future climate change. Fish were exposed to an acute (30 min) increase in salinity (50 ppt), acidity (decrease in pH by 0.5 units) or temperature (7–10°C), or temperature and acidity combined, and held in these conditions for 6 h. Their physiological responses were compared across seasons (i.e. summer vs. winter). Bonefish (Albula vulpes) exposed to environmental challenges in the summer experienced a suite of blood-based osmotic and ionic disturbances relative to fish held in ambient conditions, with thermal challenges (particularly in the summer) being the most challenging. Conversely, no significant treatment effects were observed for yellowfin mojarra (Gerres cinereus) or checkered puffer (Sphoeroides testudineus) in either season. Together, results from this study demonstrate that acute climate-induced changes to thermal habitat will be the most challenging for sub-tropical fishes (particularly in the summer) relative to salinity and pH stressors, but significant variation across species exists.
PubDate: 2014-07-29T23:42:02-07:00
DOI: 10.1093/conphys/cou028|hwp:master-id:conphys;cou028
Issue No: Vol. 2, No. 1 (2014)
- A review of factors influencing the stress response in Australian
Authors: Hing, S; Narayan, E, Thompson, R. C. A, Godfrey, S.
Pages: cou027 - cou027
Abstract: Many Australian marsupials are threatened species. In order to manage in situ and ex situ populations effectively, it is important to understand how marsupials respond to threats. Stress physiology (the study of the response of animals to challenging stimuli), a key approach in conservation physiology, can be used to characterize the physiological response of wildlife to threats. We reviewed the literature on the measurement of glucocorticoids (GCs), endocrine indicators of stress, in order to understand the stress response to conservation-relevant stressors in Australian marsupials and identified 29 studies. These studies employed a range of methods to measure GCs, with faecal glucocorticoid metabolite enzyme immunoassay being the most common method. The main stressors considered in studies of marsupials were capture and handling. To date, the benefits of stress physiology have yet to be harnessed fully in marsupial conservation. Despite a theoretical base dating back to the 1960s, GCs have only been used to understand how 21 of the 142 extant species of Australian marsupial respond to stressors. These studies include merely six of the 60 marsupial species of conservation concern (IUCN Near Threatened to Critically Endangered). Furthermore, the fitness consequences of stress for Australian marsupials are rarely examined. Individual and species differences in the physiological stress response also require further investigation, because significant species-specific variations in GC levels in response to stressors can shed light on why some individuals or species are more vulnerable to stress factors while others appear more resilient. This review summarizes trends, knowledge gaps and future research directions for stress physiology research in Australian marsupial conservation.
PubDate: 2014-07-23T22:57:03-07:00
DOI: 10.1093/conphys/cou027|hwp:master-id:conphys;cou027
Issue No: Vol. 2, No. 1 (2014)
- Quantifying long-term stress in brown bears with the hair cortisol
concentration: a biomarker that may be confounded by rapid changes in
response to capture and handling
Authors: Cattet, M; Macbeth, B. J, Janz, D. M, Zedrosser, A, Swenson, J. E, Dumond, M, Stenhouse, G. B.
Pages: cou026 - cou026
Abstract: The measurement of cortisol in hair is becoming important in studying the role of stress in the life history, health and ecology of wild mammals. The hair cortisol concentration (HCC) is generally believed to be a reliable indicator of long-term stress that can reflect frequent or prolonged activation of the hypothalamic–pituitary–adrenal axis over weeks to months through passive diffusion from the blood supply to the follicular cells that produce the hair. Diffusion of cortisol from tissues surrounding the follicle and glandular secretions (sebum and sweat) that coat the growing hair may also affect the HCC, but the extent of these effects is thought to be minimal. In this study, we report on a range of factors that are associated with, and possibly influence, cortisol concentrations in the hair of free-ranging brown bears (Ursus arctos). Through two levels of analyses that differed in sample sizes and availability of predictor variables, we identified the presence or absence of capture, restraint and handling, as well as different methods of capture, as significant factors that appeared to influence HCC in a time frame that was too short (minutes to hours) to be explained by passive diffusion from the blood supply alone. Furthermore, our results suggest that HCC was altered after hair growth had ceased and blood supply to the hair follicle was terminated. However, we also confirmed that HCC was inversely associated with brown bear body condition and was, therefore, responsive to diminished food availability/quality and possibly other long-term stressors that affect body condition. Collectively, our findings emphasize the importance of further elucidating the mechanisms of cortisol accumulation in hair and the influence of long- and short-term stressors on these mechanisms.
PubDate: 2014-07-16T22:23:07-07:00
DOI: 10.1093/conphys/cou026|hwp:master-id:conphys;cou026
Issue No: Vol. 2, No. 1 (2014)
- Ice age fish in a warming world: minimal variation in thermal acclimation
capacity among lake trout (Salvelinus namaycush) populations
Authors: Kelly, N. I; Burness, G, McDermid, J. L, Wilson, C. C.
Pages: cou025 - cou025
Abstract: In the face of climate change, the persistence of cold-adapted species will depend on their adaptive capacity for physiological traits within and among populations. The lake trout (Salvelinus namaycush) is a cold-adapted salmonid and a relict from the last ice age that is well suited as a model species for studying the predicted effects of climate change on coldwater fishes. We investigated the thermal acclimation capacity of upper temperature resistance and metabolism of lake trout from four populations across four acclimation temperatures. Individuals were reared from egg fertilization onward in a common environment and, at 2 years of age, were acclimated to 8, 11, 15 or 19°C. Although one population had a slightly higher maximal metabolic rate (MMR), higher metabolic scope for activity and faster metabolic recovery across all temperatures, there was no interpopulation variation for critical thermal maximum (CTM) or routine metabolic rate (RMR) or for the thermal acclimation capacity of CTM, RMR, MMR or metabolic scope. Across the four acclimation temperatures, there was a 3°C maximal increase in CTM and 3-fold increase in RMR for all populations. Above 15°C, a decline in MMR and increase in RMR resulted in sharply reduced metabolic scope for all populations acclimated at 19°C. Together, these data suggest there is limited variation among lake trout populations in thermal physiology or capacity for thermal acclimatization, and that climate change may impact lake trout populations in a similar manner across a wide geographical range. Understanding the effect of elevated temperatures on the thermal physiology of this economically and ecologically important cold-adapted species will help inform management and conservation strategies for the long-term sustainability of lake trout populations.
PubDate: 2014-07-16T22:23:07-07:00
DOI: 10.1093/conphys/cou025|hwp:master-id:conphys;cou025
Issue No: Vol. 2, No. 1 (2014)
- Conservation physiology across scales: insights from the marine realm
Authors: Cooke, S. J; Killen, S. S, Metcalfe, J. D, McKenzie, D. J, Mouillot, D, Jorgensen, C, Peck, M. A.
Pages: cou024 - cou024
Abstract: As the field of conservation physiology develops and becomes increasingly integrated with ecology and conservation science, the fundamental concept of scale is being recognized as important, particularly for ensuring that physiological knowledge is contextualized in a manner most relevant to policy makers, conservation practitioners and stakeholders. Failure to consider the importance of scale in conservation physiology—both the challenges and the opportunities that it creates—will impede the ability of this discipline to generate the scientific understanding needed to contribute to meaningful conservation outcomes. Here, we have focused on five aspects of scale: biological, spatial, temporal, allometric and phylogenetic. We also considered the scale of policy and policy application relevant to those five types of scale as well as the merits of upscaling and downscaling to explore and address conservation problems. Although relevant to all systems (e.g. freshwater, terrestrial) we have used examples from the marine realm, with a particular emphasis on fishes, given the fact that there is existing discourse regarding scale and its relevance for marine conservation and management. Our synthesis revealed that all five aspects of scale are relevant to conservation physiology, with many aspects inherently linked. It is apparent that there are both opportunities and challenges afforded by working across scales but, to understand mechanisms underlying conservation problems, it is essential to consider scale of all sorts and to work across scales to the greatest extent possible. Moreover, given that the scales in biological processes will often not match policy and management scales, conservation physiology needs to show how it is relevant to aspects at different policy/management scales, change the scales at which policy/management intervention is applied or be prepared to be ignored.
PubDate: 2014-07-08T22:15:43-07:00
DOI: 10.1093/conphys/cou024|hwp:master-id:conphys;cou024
Issue No: Vol. 2, No. 1 (2014)
- Measures of physiological stress: a transparent or opaque window into the
status, management and conservation of species?
Authors: Dantzer, B; Fletcher, Q. E, Boonstra, R, Sheriff, M. J.
Pages: cou023 - cou023
Abstract: Conservation physiology proposes that measures of physiological stress (glucocorticoid levels) can be used to assess the status and future fate of natural populations. Increases in glucocorticoids may reflect a more challenging environment, suggesting that the influence of human activities on free-living animals could be quantified by measuring glucocorticoids. Biomedical studies suggest that chronic increases in glucocorticoids can have detrimental effects on survival and reproduction, which could influence the viability of populations. Here, we discuss the use of measurements of glucocorticoids in conservation physiology. We first provide an overview of the different methods to quantify glucocorticoids and their utility in conservation physiology. We then discuss five questions we think are essential for conservation physiologists to address. We highlight how intrinsic (e.g. sex, reproductive status, age, recent experiences) and ecological factors (e.g. predation, food availability, snowfall) can, by themselves or through their interactions with anthropogenic disturbances, affect the physiological stress response and mask any general patterns about the effects of anthropogenic disturbances on glucocorticoids. Using a meta-analysis, we show that anthropogenic disturbances are consistently associated with increased glucocorticoids regardless of the type of human disturbance. We also show that males may be more sensitive to anthropogenic disturbances than females and that faecal glucocorticoids, but not baseline plasma glucocorticoids, consistently increase in response to anthropogenic disturbances. Finally, we discuss how increases in glucocorticoids in free-living animals can sometimes enhance survival and reproduction. Unfortunately, our literature analysis indicates that this observation has not yet gained traction, and very few studies have shown that increases in glucocorticoid levels resulting from anthropogenic disturbances decrease survival or reproduction. We think that the use of measures of glucocorticoids in conservation physiology has tremendous potential, but there are still a number of methodological concerns, in addition to several crucial questions that should be addressed.
PubDate: 2014-06-27T23:36:29-07:00
DOI: 10.1093/conphys/cou023|hwp:master-id:conphys;cou023
Issue No: Vol. 2, No. 1 (2014)
- Body condition predicts energy stores in apex predatory sharks
Authors: Gallagher, A. J; Wagner, D. N, Irschick, D. J, Hammerschlag, N.
Pages: cou022 - cou022
Abstract: Animal condition typically reflects the accumulation of energy stores (e.g. fatty acids), which can influence an individual's decision to undertake challenging life-history events, such as migration and reproduction. Accordingly, researchers often use measures of animal body size and/or weight as an index of condition. However, values of condition, such as fatty acid levels, may not always reflect the physiological state of animals accurately. While the relationships between condition indices and energy stores have been explored in some species (e.g. birds), they have yet to be examined in top predatory fishes, which often undertake extensive and energetically expensive migrations. We used an apex predatory shark (Galeocerdo cuvier, the tiger shark) as a model species to evaluate the relationship between triglycerides (energy metabolite) and a metric of overall body condition. We captured, blood sampled, measured and released 28 sharks (size range 125–303 cm pre-caudal length). In the laboratory, we assayed each plasma sample for triglyceride values. We detected a positive and significant relationship between condition and triglyceride values (P
PubDate: 2014-06-23T00:53:12-07:00
DOI: 10.1093/conphys/cou022|hwp:master-id:conphys;cou022
Issue No: Vol. 2, No. 1 (2014)
- Body condition and habitat use by Hermann's tortoises in burnt and intact
Authors: Lecq, S; Ballouard, J.- M, Caron, S, Livoreil, B, Seynaeve, V, Matthieu, L.- A, Bonnet, X.
Pages: cou019 - cou019
Abstract: In Mediterranean regions, fires threaten terrestrial tortoises. Nevertheless, varying proportions of adults survive fire; these surviving individuals can play a central role for population recovery. The regions devastated by fire often include important habitat of Hermann's tortoises (Testudo hermanni hermanni), so assessing the ability of survivors to persist is essential for conserving the species. Body-condition indices provide an integrative estimate of how well individuals cope with environmental variations and impacts, including fires. Between 2002 and 2009, we monitored Hermann's tortoises in intact and burnt habitats in southeastern France. In summer 2003, a strong fire ravaged half of the surveyed zone, providing an opportunity to compare body condition of tortoises between intact and burnt areas over time. Six years later, the impact of fire on vegetation was still marked; large trees were abundant in the intact area, whereas open shrub vegetation prevailed in the burnt area. In both areas, the mean body condition of tortoises fluctuated over time; however, there were no differences between the two areas. A radio-tracking experiment demonstrated that individuals from each area were residents, and not vagrants commuting between areas. We also assessed changes in body condition and microhabitat use in radio-tracked individuals. We found no significant differences between the tortoises living in the burnt and intact areas, despite subtle differences in habitat use. In conclusion: (i) surviving tortoises in an area ravaged by fire can maintain their body condition like individuals living in an intact area, and thus, individuals from burnt areas should not be translocated to supposedly better areas; and (ii) depopulated burnt areas are likely to be appropriate for population-augmentation programmes.
PubDate: 2014-06-12T01:05:47-07:00
DOI: 10.1093/conphys/cou019|hwp:master-id:conphys;cou019
Issue No: Vol. 2, No. 1 (2014)
- Short-term episodes of imposed fasting have a greater effect on young
northern fur seals (Callorhinus ursinus) in summer than in winter
Authors: Rosen, D. A. S; Volpov, B. L, Trites, A. W.
Pages: cou021 - cou021
Abstract: An unexpected shortage of food may affect wildlife in a different way depending on the time of year when it occurs. We imposed 48 h fasts on six female northern fur seals (Callorhinus ursinus; ages 6–24 months) to identify times of year when they might be particularly sensitive to interruptions in food supply. We monitored changes in their resting metabolic rates and their metabolic response to thermal challenges, and also examined potential bioenergetic causes for seasonal differences in body mass loss. The pre-fast metabolism of the fur seals while in ambient air or submerged in water at 4°C was higher during summer (June to Sepember) than winter (November to March), and submergence did not significantly increase metabolism, indicating a lack of additional thermoregulatory costs. There was no evidence of metabolic depression following the fasting periods, nor did metabolism increase during the post-fast thermal challenge, suggesting that mass loss did not negatively impact thermoregulatory capacity. However, the fur seals lost mass at greater rates while fasting during the summer months, when metabolism is normally high to facilitate faster growth rates (which would ordinarily have been supported by higher food intake levels). Our findings suggest that summer is a more critical time of year than winter for young northern fur seals to obtain adequate nutrition.
PubDate: 2014-06-06T22:49:13-07:00
DOI: 10.1093/conphys/cou021|hwp:master-id:conphys;cou021
Issue No: Vol. 2, No. 1 (2014)
- Exposure to bloom-like concentrations of two marine Synechococcus
cyanobacteria (strains CC9311 and CC9902) differentially alters fish
Authors: Hamilton, T. J; Paz-Yepes, J, Morrison, R. A, Palenik, B, Tresguerres, M.
Pages: cou020 - cou020
Abstract: Coastal California experiences large-scale blooms of Synechococcus cyanobacteria, which are predicted to become more prevalent by the end of the 21st century as a result of global climate change. This study investigated whether exposure to bloom-like concentrations of two Synechococcus strains, CC9311 and CC9902, alters fish behaviour. Black perch (Embiotoca jacksoni) were exposed to Synechococcus strain CC9311 or CC9902 (1.5 x 106 cells ml–1) or to control seawater in experimental aquaria for 3 days. Fish movement inside a testing arena was then recorded and analysed using video camera-based motion-tracking software. Compared with control fish, fish exposed to CC9311 demonstrated a significant preference for the dark zone of the tank in the light–dark test, which is an indication of increased anxiety. Furthermore, fish exposed to CC9311 also had a statistically significant decrease in velocity and increase in immobility and they meandered more in comparison to control fish. There was a similar trend in velocity, immobility and meandering in fish exposed to CC9902, but there were no significant differences in behaviour or locomotion between this group and control fish. Identical results were obtained with a second batch of fish. Additionally, in this second trial we also investigated whether fish would recover after a 3 day period in seawater without cyanobacteria. Indeed, there were no longer any significant differences in behaviour among treatments, demonstrating that the sp. CC9311-induced alteration of behaviour is reversible. These results demonstrate that blooms of specific marine Synechococcus strains can induce differential sublethal effects in fish, namely alterations light–dark preference behaviour and motility.
PubDate: 2014-06-05T23:35:49-07:00
DOI: 10.1093/conphys/cou020|hwp:master-id:conphys;cou020
Issue No: Vol. 2, No. 1 (2014)
- Effects of reduced winter duration on seed dormancy and germination in six
populations of the alpine herb Aciphyllya glacialis (Apiaceae)
Authors: Hoyle, G. L; Cordiner, H, Good, R. B, Nicotra, A. B.
Pages: cou015 - cou015
Abstract: The life stages of seed germination and seedling establishment play a vital role in maintaining plant populations and determining range dynamics of species. Thus, it is not surprising that specific germination requirements and dormancy mechanisms have evolved in all major angiosperm clades. In a rapidly changing climate, we face growing pressure to manage, conserve and restore native plant species and communities. To achieve these aims, we require solid knowledge of whether and how seed germination requirements and dormancy status vary between different populations of a given species and how germination strategies may be affected by warming climatic conditions. We assessed the effect of decreasing durations of cold stratification (i.e. conditions representing a shortened winter as predicted under climate change) on germination and dormancy of the alpine herb Aciphylla glacialis. Our results confirmed previous research showing that A. glacialis seeds possess physiological dormancy that can be alleviated by cold stratification. In addition, the results demonstrated that A. glacialis seeds have underdeveloped embryos at dispersal; these grow to germinable size following 4–9 weeks at both constant 5°C and 10–5°C (day–night) temperatures. We conclude that A. glacialis exhibits morphophysiological dormancy. Furthermore, we found that the final percentage germination and dormancy status varied significantly among natural populations and that this variation did not correlate with elevation at the site of seed origin. Seeds germinated following 6–8 weeks of cold stratification, and seedlings showed no detrimental effects as a result of shorter stratification periods. Together, these results suggest that reduced duration of winter is unlikely to have direct negative impacts on germination or early seedling growth in A. glacialis. The causes and implications of the population variation in germination traits are discussed.
PubDate: 2014-05-30T02:05:16-07:00
DOI: 10.1093/conphys/cou015|hwp:master-id:conphys;cou015
Issue No: Vol. 2, No. 1 (2014)
- Non-lethal assessment of the reproductive status of broadnose sevengill
sharks (Notorynchus cepedianus) to determine the significance of habitat
use in coastal areas
Authors: Awruch, C. A; Jones, S. M, Asorey, M. G, Barnett, A.
Pages: cou013 - cou013
Abstract: Identification of the importance of habitats that are frequently used by any species is essential to a complete understanding of the species' biology and to incorporate their ecological role into conservation and management programmes. In this context, the present study investigated whether Tasmanian coastal waters have any reproductive relevance for the broadnose sevengill shark (Notorynchus cepedianus). Although this species is a large coast-associated apex predator in these areas, there is a complete gap in understanding the role that these coastal systems could play in its reproduction. Reproductive hormones were used as a non-lethal method to address the reproductive biology of this species. Females seemed to have at least a bi-annual reproductive cycle, being pregnant for ~1 year and spending at least 1 year non-pregnant, with the ovulatory cycle separated from gestation. Mature females were found to be ovulating, in the initial stages of pregnancy, resting or starting a new vitellogenic cycle. Notorynchus cepedianus did not use these coastal habitats for mating or as a pupping ground. Although the mating season was distinguished between September to April, only 22% of males showed mating scars during the peak of the mating period and no near-term pregnant females were observed. Thus, despite these coastal waters being an important foraging ground for this species, these areas did not have any reproductive relevance. In consequence, future management and conservation planning programmes need to identify whether there are other areas in Tasmania that play a critical role for reproductive purposes in this species. Finally, although previous studies have linked reproductive hormones with external examination of the gonads to validate the use of steroids as a non-lethal tool to address reproduction, the present study used this methodology without killing any animals. This has important implications for conservation programmes of threatened and endangered species worldwide where the methodology cannot be validated.
PubDate: 2014-05-30T02:05:16-07:00
DOI: 10.1093/conphys/cou013|hwp:master-id:conphys;cou013
Issue No: Vol. 2, No. 1 (2014)
- Exposure to residual concentrations of elements from a remediated coal fly
ash spill does not adversely influence stress and immune responses of
nestling tree swallows
Authors: Beck, M. L; Hopkins, W. A, Hallagan, J. J, Jackson, B. P, Hawley, D. M.
Pages: cou018 - cou018
Abstract: Anthropogenic activities often produce pollutants that can affect the physiology, growth and reproductive success of wildlife. Many metals and trace elements play important roles in physiological processes, and exposure to even moderately elevated concentrations of essential and non-essential elements could have subtle effects on physiology, particularly during development. We examined the effects of exposure to a number of elements from a coal fly ash spill that occurred in December 2008 and has since been remediated on the stress and immune responses of nestling tree swallows. We found that nestlings at the site of the spill had significantly greater blood concentrations of Cu, Hg, Se and Zn in 2011, but greater concentrations only of Se in 2012, in comparison to reference colonies. The concentrations of elements were below levels of significant toxicological concern in both years. In 2011, we found no relationship between exposure to elements associated with the spill and basal or stress-induced corticosterone concentrations in nestlings. In 2012, we found that Se exposure was not associated with cell-mediated immunity based on the response to phytohaemagglutinin injection. However, the bactericidal capacity of nestling plasma had a positive but weak association with blood Se concentrations, and this association was stronger at the spill site. Our results indicate that exposure to these low concentrations of elements had few effects on nestling endocrine and immune physiology. The long-term health consequences of low-level exposure to elements and of exposure to greater element concentrations in avian species require additional study.
PubDate: 2014-05-28T00:27:20-07:00
DOI: 10.1093/conphys/cou018|hwp:master-id:conphys;cou018
Issue No: Vol. 2, No. 1 (2014)
- Native trees show conservative water use relative to invasive trees:
results from a removal experiment in a Hawaiian wet forest
Authors: Cavaleri, M. A; Ostertag, R, Cordell, S, Sack, L.
Pages: cou016 - cou016
Abstract: While the supply of freshwater is expected to decline in many regions in the coming decades, invasive plant species, often 'high water spenders', are greatly expanding their ranges worldwide. In this study, we quantified the ecohydrological differences between native and invasive trees and also the effects of woody invasive removal on plot-level water use in a heavily invaded mono-dominant lowland wet tropical forest on the Island of Hawaii. We measured transpiration rates of co-occurring native and invasive tree species with and without woody invasive removal treatments. Twenty native Metrosideros polymorpha and 10 trees each of three invasive species, Cecropia obtusifolia, Macaranga mappa and Melastoma septemnervium, were instrumented with heat-dissipation sap-flux probes in four 100 m2 plots (two invaded, two removal) for 10 months. In the invaded plots, where both natives and invasives were present, Metrosideros had the lowest sap-flow rates per unit sapwood, but the highest sap-flow rates per whole tree, owing to its larger mean diameter than the invasive trees. Stand-level water use within the removal plots was half that of the invaded plots, even though the removal of invasives caused a small but significant increase in compensatory water use by the remaining native trees. By investigating the effects of invasive species on ecohydrology and comparing native vs. invasive physiological traits, we not only gain understanding about the functioning of invasive species, but we also highlight potential water-conservation strategies for heavily invaded mono-dominant tropical forests worldwide. Native-dominated forests free of invasive species can be conservative in overall water use, providing a strong rationale for the control of invasive species and preservation of native-dominated stands.
PubDate: 2014-05-19T01:13:08-07:00
DOI: 10.1093/conphys/cou016|hwp:master-id:conphys;cou016
Issue No: Vol. 2, No. 1 (2014)
- Physiological assessment of the effects of changing water levels
associated with reservoir management on fattening rates of neotropical
migrants at a stopover site
Authors: Wagner, D. N; Green, D. J, Pavlik, M, Cooper, J, Williams, T. D.
Pages: cou017 - cou017
Abstract: Riparian habitat makes up a small fraction of the landscape but provides important stopover habitat for migratory birds. Hydroelectric dam operations cause fluctuations in water levels that can change the amount or quality of riparian habitat, which in turn might affect potential fattening rates of migrant birds. Here we used plasma metabolite analysis to estimate variation in fattening rate in relationship to variable water levels associated with reservoir management in four species of neotropical migratory songbirds using riparian habitat at a dam-impacted stopover site in Revelstoke, British Columbia, Canada. Residual plasma triglyceride, our measure of estimated fattening rate, varied systematically with time of day and Julian date and varied consistently among species, but did not vary with age or sex. Controlling for potentially confounding variables, we found no inter-annual variation in estimated fattening rate, even though there were marked differences in water levels among years. Likewise, there was no relationship between daily variation in water levels and estimated fattening rate. Data on feather isotopes (D), indicative of migratory origin, did not add explanatory power to our models. There was inter-annual variation in plasma glycerol and β-hydroxybutyrate levels and significant, though weak, relationships between these metabolites and water level (higher metabolite levels when drier) that might indicate effects on 'body condition' independent of fattening rate. Our study suggests that, at present, although hydroelectric dam operations influence water levels in the Arrows Lake Reservoir and adjacent riparian habitats, this does not significantly impact fattening rates of migratory passerines using these habitats.
PubDate: 2014-05-15T07:34:44-07:00
DOI: 10.1093/conphys/cou017|hwp:master-id:conphys;cou017
Issue No: Vol. 2, No. 1 (2014)
- Biomarkers of oxidative status: missing tools in conservation physiology
Authors: Beaulieu, M; Costantini, D.
Pages: cou014 - cou014
Abstract: Recent ecological studies have shown that oxidative status could have a significant impact on fitness components in wild animals. Not only can oxidative status reflect the environmental conditions that animals experience, but it can also predict their chances of reproduction and survival in the future in their natural habitat. Such important characteristics make markers of oxidative status informative tools to evaluate a priori individual perspectives of reproduction and survival as well as to assess a posteriori the effect of human activities on the fitness of species of conservation concern and wildlife in general. Markers of oxidative status may therefore help conservation practitioners to identify conservation threats to animal populations and to maximize the success of wildlife management. Despite these potential benefits for animal conservation programmes, up to now markers of oxidative status have only been reported anecdotally in conservation studies. The aim of this review is therefore to raise awareness by conservation practitioners of the use of markers of oxidative status. Towards this end, we first describe how environmental disruptions due to human activities can translate into variation in oxidative status. Second, we show how individual and population variation in oxidative status may contribute to the success or the failure of reintroduction or translocation programmes. Finally, we emphasize the technical features specific to the measurement of markers of oxidative status in conservation programmes, which may help investigators with the interpretation of their results. Such prior knowledge about markers of oxidative status may encourage conservation physiologists to use them in order to enhance the success of conservation programmes and wildlife management.
PubDate: 2014-05-12T01:47:50-07:00
DOI: 10.1093/conphys/cou014|hwp:master-id:conphys;cou014
Issue No: Vol. 2, No. 1 (2014)
- Stress and reproductive hormones reflect inter-specific social and
nutritional conditions mediated by resource availability in a bear-salmon
Authors: Bryan, H. M; Darimont, C. T, Paquet, P. C, Wynne-Edwards, K. E, Smits, J. E. G.
Pages: cou010 - cou010
Abstract: Food availability can influence the nutritional and social dynamics within and among species. Our investigation focused on grizzly and black bears in coastal British Columbia, Canada, where recent and dramatic declines in their primary prey (salmon) raise concerns about potentially negative effects on bear physiology. We examined how salmon availability relates to stress and reproductive hormones in coastal grizzly (n = 69) and black bears (n = 68) using cortisol and testosterone. In hair samples from genotyped individuals, we quantified salmon consumption using stable isotope analysis and hormone levels by enzyme immunoassay. To estimate the salmon biomass available to each bear, we developed a spatially explicit approach based on typical bear home-range sizes. Next, we compared the relative importance of salmon consumption and salmon availability on hormone levels in male bears using an information theoretical approach. Cortisol in grizzly bears was higher in individuals that consumed less salmon, possibly reflecting nutritional stress. In black bears, cortisol was better predicted by salmon availability than salmon consumption; specifically, individuals in areas and years with low salmon availability showed higher cortisol levels. This indicates that cortisol in black bears is more strongly influenced by the socially competitive environment mediated by salmon availability than by nutritional requirements. In both species, testosterone generally decreased with increasing salmon availability, possibly reflecting a less competitive environment when salmon were abundant. Differences between species could relate to different nutritional requirements, social densities and competitive behaviour and/or habitat use. We present a conceptual model to inform further investigations in this and other systems. Our approach, which combines data on multiple hormones with dietary and spatial information corresponding to the year of hair growth, provides a promising tool for evaluating the responses of a broad spectrum of wildlife to changes in food availability or other environmental conditions.
PubDate: 2014-05-02T02:35:19-07:00
DOI: 10.1093/conphys/cou010|hwp:master-id:conphys;cou010
Issue No: Vol. 2, No. 1 (2014)
- First line of defence: the role of sloughing in the regulation of
cutaneous microbes in frogs
Authors: Cramp, R. L; McPhee, R. K, Meyer, E. A, Ohmer, M. E, Franklin, C. E.
Pages: cou012 - cou012
Abstract: Amphibian populations worldwide are currently experiencing unprecedented declines due to the combined effects of emerging infectious disease and climate change. The skin is the first line of defence in preventing establishment of pathogens and associated infections. Although amphibians undergo regular sloughing of the outer layer of the skin, the potential for regular sloughing to play a role in influencing cutaneous microbial populations and pathogens has been largely overlooked. In the present study, we assessed the effect of skin sloughing on cultivable cutaneous bacterial abundance in the green tree frog (Litoria caerulea). We also examined the effects of temperature and hydric environment on sloughing frequency and microbial re-establishment rates. Our data showed that cultivable cutaneous bacterial abundance was significantly reduced by sloughing events, and frogs kept at 'summer' temperatures (23–33°C) sloughed almost twice as frequently as those maintained at 'winter' temperatures (13–23°C). No effect of hydric environment on sloughing frequency was observed, but we did find that sloughing in L. caerulea appeared to be linked to ambient light cycles. Examination of the effect of sloughing on microbial recolonization indicated that at cool temperatures, an extended intermoult interval allowed microbial abundance to reach higher levels than at warmer 'summer' temperatures (when the intermoult interval was significantly reduced). Our data suggest that sloughing may significantly influence the establishment and/or maintenance of cutaneous bacterial populations (pathogenic, mutualistic and/or commensal) and this, in turn, may be affected by environmental factors, such as ambient light and temperature. These findings are likely to be important for our understanding of the ecology of skin-based pathogens, such as the amphibian chytrid fungus, Batrachochytrium dendrobatidis.
PubDate: 2014-04-21T22:56:12-07:00
DOI: 10.1093/conphys/cou012|hwp:master-id:conphys;cou012
Issue No: Vol. 2, No. 1 (2014)
- Use of portable blood physiology point-of-care devices for basic and
applied research on vertebrates: a review
Authors: Stoot, L. J; Cairns, N. A, Cull, F, Taylor, J. J, Jeffrey, J. D, Morin, F, Mandelman, J. W, Clark, T. D, Cooke, S. J.
Pages: cou011 - cou011
Abstract: Non-human vertebrate blood is commonly collected and assayed for a variety of applications, including veterinary diagnostics and physiological research. Small, often non-lethal samples enable the assessment and monitoring of the physiological state and health of the individual. Traditionally, studies that rely on blood physiology have focused on captive animals or, in studies conducted in remote settings, have required the preservation and transport of samples for later analysis. In either situation, large, laboratory-bound equipment and traditional assays and analytical protocols are required. The use of point-of-care (POC) devices to measure various secondary blood physiological parameters, such as metabolites, blood gases and ions, has become increasingly popular recently, due to immediate results and their portability, which allows the freedom to study organisms in the wild. Here, we review the current uses of POC devices and their applicability to basic and applied studies on a variety of non-domesticated species. We located 79 individual studies that focused on non-domesticated vertebrates, including validation and application of POC tools. Studies focused on a wide spectrum of taxa, including mammals, birds and herptiles, although the majority of studies focused on fish, and typical variables measured included blood glucose, lactate and pH. We found that calibrations for species-specific blood physiology values are necessary, because ranges can vary within and among taxa and are sometimes outside the measurable range of the devices. In addition, although POC devices are portable and robust, most require durable cases, they are seldom waterproof/water-resistant, and factors such as humidity and temperature can affect the performance of the device. Overall, most studies concluded that POC devices are suitable alternatives to traditional laboratory devices and eliminate the need for transport of samples; however, there is a need for greater emphasis on rigorous calibration and validation of these units and appreciation of their limitations.
PubDate: 2014-04-04T23:05:56-07:00
DOI: 10.1093/conphys/cou011|hwp:master-id:conphys;cou011
Issue No: Vol. 2, No. 1 (2014)
- Captivity results in disparate loss of gut microbial diversity in closely
related hosts
Authors: Kohl, K. D; Skopec, M. M, Dearing, M. D.
Pages: cou009 - cou009
Abstract: The gastrointestinal tracts of animals contain diverse communities of microbes that provide a number of services to their hosts. There is recent concern that these communities may be lost as animals enter captive breeding programmes, due to changes in diet and/or exposure to environmental sources. However, empirical evidence documenting the effects of captivity and captive birth on gut communities is lacking. We conducted three studies to advance our knowledge in this area. First, we compared changes in microbial diversity of the gut communities of two species of woodrats (Neotoma albigula, a dietary generalist, and Neotoma stephensi, which specializes on juniper) before and after 6–9 months in captivity. Second, we investigated whether reintroduction of the natural diet of N. stephensi could restore microbial diversity. Third, we compared the microbial communities between offspring born in captivity and their mothers. We found that the dietary specialist, N. stephensi, lost a greater proportion of its native gut microbiota and overall diversity in response to captivity compared with N. albigula. Addition of the natural diet increased the proportion of the original microbiota but did not restore overall diversity in N. stephensi. Offspring of N. albigula more closely resembled their mothers compared with offspring–mother pairs of N. stephensi. This research suggests that the microbiota of dietary specialists may be more susceptible to captivity. Furthermore, this work highlights the need for further studies investigating the mechanisms underlying how loss of microbial diversity may vary between hosts and what an acceptable level of diversity loss may be to a host. This knowledge will aid conservation biologists in designing captive breeding programmes effective at maintaining microbial diversity. Sequence Accession Numbers: NCBI's Sequence Read Archive (SRA) – SRP033616
PubDate: 2014-03-24T06:27:48-07:00
DOI: 10.1093/conphys/cou009|hwp:master-id:conphys;cou009
Issue No: Vol. 2, No. 1 (2014)
- Ontogeny influences sensitivity to climate change stressors in an
endangered fish
Authors: Komoroske, L. M; Connon, R. E, Lindberg, J, Cheng, B. S, Castillo, G, Hasenbein, M, Fangue, N. A.
Pages: cou008 - cou008
Abstract: Coastal ecosystems are among the most human-impacted habitats globally, and their management is often critically linked to recovery of declining native species. In the San Francisco Estuary, the Delta Smelt (Hypomesus transpacificus) is an endemic, endangered fish strongly tied to Californian conservation planning. The complex life history of Delta Smelt combined with dynamic seasonal and spatial abiotic conditions result in dissimilar environments experienced among ontogenetic stages, which may yield stage-specific susceptibility to abiotic stressors. Climate change is forecasted to increase San Francisco Estuary water temperature and salinity; therefore, understanding the influences of ontogeny and phenotypic plasticity on tolerance to these critical environmental parameters is particularly important for Delta Smelt and other San Francisco Estuary fishes. We assessed thermal and salinity limits in several ontogenetic stages and acclimation states of Delta Smelt, and paired these data with environmental data to evaluate sensitivity to climate-change stressors. Thermal tolerance decreased among successive stages, with larval fish exhibiting the highest tolerance and post-spawning adults having the lowest. Delta Smelt had limited capacity to increase tolerance through thermal acclimation, and comparisons with field temperature data revealed that juvenile tolerance limits are the closest to current environmental conditions, which may make this stage especially susceptible to future climate warming. Maximal water temperatures observed in situ exceeded tolerance limits of juveniles and adults. Although these temperature events are currently rare, if they increase in frequency as predicted, it could result in habitat loss at these locations despite other favourable conditions for Delta Smelt. In contrast, Delta Smelt tolerated salinities spanning the range of expected environmental conditions for each ontogenetic stage, but salinity did impact survival in juvenile and adult stages in exposures over acute time scales. Our results underscore the importance of considering ontogeny and phenotypic plasticity in assessing the impacts of climate change, particularly for species adapted to spatially and temporally heterogeneous environments.
PubDate: 2014-03-11T00:08:52-07:00
DOI: 10.1093/conphys/cou008|hwp:master-id:conphys;cou008
Issue No: Vol. 2, No. 1 (2014)
- High water-use efficiency and growth contribute to success of non-native
Erodium cicutarium in a Sonoran Desert winter annual community
Authors: Kimball, S; Gremer, J. R, Barron-Gafford, G. A, Angert, A. L, Huxman, T. E, Venable, D. L.
Pages: cou006 - cou006
Abstract: The success of non-native, invasive species may be due to release from natural enemies, superior competitive abilities, or both. In the Sonoran Desert, Erodium cicutarium has increased in abundance over the last 30 years. While native species in this flora exhibit a strong among-species trade-off between relative growth rate and water-use efficiency, E. cicutarium seems to have a higher relative growth rate for its water-use efficiency value relative to the pattern across native species. This novel trait combination could provide the non-native species with a competitive advantage in this water-limited environment. To test the hypothesis that E. cicutarium is able to achieve high growth rates due to release from native herbivores, we compared the effects of herbivory on E. cicutarium and its native congener, Erodium texanum. We also compared these two species across a range of environmental conditions, both in a common garden and in two distinct seasons in the field, using growth analysis, isotopic compositions and leaf-level gas exchange. Additionally, we compared the competitive abilities of the two Erodium species in a greenhouse experiment. We found no evidence of herbivory to either species. Physiological measurements in a common environment revealed that E. cicutarium was able to achieve high growth rates while simultaneously controlling leaf-level water loss. Non-native E. cicutarium responded to favourable conditions in the field with greater specific leaf area and leaf area ratio than native E. texanum. The non-native Erodium was a stronger competitor than its native congener in a greenhouse competition experiment. The ability to maintain relatively higher values of water-use efficiency:relative growth rate in comparison to the native flora may be what enables E. cictarium to outcompete native species in both wet and dry years, resulting in an increase in abundance in the highly variable Sonoran Desert.
PubDate: 2014-03-05T22:23:24-08:00
DOI: 10.1093/conphys/cou006|hwp:master-id:conphys;cou006
Issue No: Vol. 2, No. 1 (2014)
- Physiological response and resilience of early life-stage Eastern oysters
(Crassostrea virginica) to past, present and future ocean acidification
Authors: Gobler, C. J; Talmage, S. C.
Pages: cou004 - cou004
Abstract: The Eastern oyster, Crassostrea virginica (Gmelin, 1791), is the second most valuable bivalve fishery in the USA and is sensitive to high levels of partial pressure of CO2 (pCO2). Here we present experiments that comprehensively examined how the ocean's past, present and projected (21st and 22nd centuries) CO2 concentrations impact the growth and physiology of larval stages of C. virginica. Crassostrea virginica larvae grown in present-day pCO2 concentrations (380 μatm) displayed higher growth and survival than individuals grown at both lower (250 μatm) and higher pCO2 levels (750 and 1500 μatm). Crassostrea virginica larvae manifested calcification rates, sizes, shell thicknesses, metamorphosis, RNA:DNA ratios and lipid contents that paralleled trends in survival, with maximal values for larvae grown at 380 μatm pCO2 and reduced performance in higher and lower pCO2 levels. While some physiological differences among oysters could be attributed to CO2-induced changes in size or calcification rates, the RNA:DNA ratios at ambient pCO2 levels were elevated, independent of these factors. Likewise, the lipid contents of individuals exposed to high pCO2 levels were depressed even when differences in calcification rates were considered. These findings reveal the cascading, interdependent impact that high CO2 can have on oyster physiology. Crassostrea virginica larvae are significantly more resistant to elevated pCO2 than other North Atlantic bivalves, such as Mercenaria mercenaria and Argopecten irradians, a finding that may be related to the biogeography and/or evolutionary history of these species and may have important implications for future bivalve restoration and aquaculture efforts.
PubDate: 2014-03-04T22:37:08-08:00
DOI: 10.1093/conphys/cou004|hwp:master-id:conphys;cou004
Issue No: Vol. 2, No. 1 (2014)
- Plant water use characteristics of five dominant shrub species of the
Lower Rio Grande Valley, Texas, USA: implications for shrubland
restoration and conservation
Authors: Adhikari, A; White, J. D.
Pages: cou005 - cou005
Abstract: The biogeographic distribution of plant species is inherently associated with the plasticity of physiological adaptations to environmental variation. For semi-arid shrublands with a legacy of saline soils, characterization of soil water-tolerant shrub species is necessary for habitat restoration given future projection of increased drought magnitude and persistence in these ecosystems. Five dominant native shrub species commonly found in the Lower Rio Grande Valley, TX, USA, were studied, namely Acacia farnesiana, Celtis ehrenbergiana, Forestiera angustifolia, Parkinsonia aculeata and Prosopis glandulosa. To simulate drought conditions, we suspended watering of healthy, greenhouse-grown plants for 4 weeks. Effects of soil salinity were also studied by dosing plants with 10% NaCl solution with suspended watering. For soil water deficit treatment, the soil water potential of P. glandulosa was the highest (–1.20 MPa), followed by A. farnesiana (–4.69 MPa), P. aculeata (–5.39 MPa), F. angustifolia (–6.20 MPa) and C. ehrenbergiana (–10.02 MPa). For the soil salinity treatment, P. glandulosa also had the highest soil water potential value (–1.60 MPa), followed by C. ehrenbergiana (–1.70 MPa), A. farnesiana (–1.84 MPa), P. aculeata (–2.04 MPa) and F. angustifolia (–6.99 MPa). Within the species, only C. ehrenbergiana and F. angustifolia for soil water deficit treatment and A. farnesiana for the salinity treatment had significantly lower soil water potential after 4 weeks of treatment (P
PubDate: 2014-02-27T03:02:17-08:00
DOI: 10.1093/conphys/cou005|hwp:master-id:conphys;cou005
Issue No: Vol. 2, No. 1 (2014)
- State of the interface between conservation and physiology: a bibliometric
Authors: Lennox, R; Cooke, S. J.
Pages: cou003 - cou003
Abstract: Contemporary conservation science benefits from the perspectives of a variety of different disciplines, including a recent synergy with physiology, an interface known as 'conservation physiology'. To evaluate the degree of interaction between conservation and animal/plant physiology, we conducted three bibliometric analyses. We first pursued the use of the term 'conservation physiology' since its first definition in 2006 to determine how frequently it has been used and in which publications. Secondly, we evaluated the occurrence of conservation terms in animal and plant physiology journals, physiological terms in conservation journals, and a combination of terms in ecology journals. Thirdly, we explored trends in a subset of conservation physiology articles published between 2006 and 2012. We identified a surge in the use of the term 'conservation physiology' in 2012, after only a slow increase in usage between 2006 and 2011. Conservation journals tend to have been significantly more active in publishing conservation physiology than animal physiology, plant physiology or ecology journals. However, we found evidence that ecology and animal physiology journals began to incorporate more conservation physiology after 2006, while conservation- and plant physiology-themed journals did not. Among 299 conservation physiology articles that we identified, vertebrate taxa have been over-represented in conservation physiology compared with their relative taxonomic abundance, invertebrate taxa have been under-represented, and plants have been represented in proportion to their relative taxonomic abundance; however, those findings are reasonably consistent with publication trends in conservation biology. Diffuse distribution of conservation physiology papers throughout the literature may have been a barrier to the growth of the subdiscipline when the interface was emerging. The introduction of the focused journal Conservation Physiology in 2013 may address that deficiency. Moreover, development of a unifying framework could help to aggregate knowledge and attract potential contributors by highlighting and facilitating access to and application of conservation physiology.
PubDate: 2014-02-25T22:45:54-08:00
DOI: 10.1093/conphys/cou003|hwp:master-id:conphys;cou003
Issue No: Vol. 2, No. 1 (2014)
- Conservation physiology of plants
Authors: van Kleunen; M.
Pages: cou007 - cou007
PubDate: 2014-02-25T22:45:54-08:00
DOI: 10.1093/conphys/cou007|hwp:master-id:conphys;cou007
Issue No: Vol. 2, No. 1 (2014)
- Seasonal trends in nesting leatherback turtle (Dermochelys coriacea) serum
proteins further verify capital breeding hypothesis
Authors: Perrault, J. R; Wyneken, J, Page-Karjian, A, Merrill, A, Miller, D. L.
Pages: cou002 - cou002
Abstract: Serum protein concentrations provide insight into the nutritional and immune status of organisms. It has been suggested that some marine turtles are capital breeders that fast during the nesting season. In this study, we documented serum proteins in neophyte and remigrant nesting leatherback sea turtles (Dermochelys coriacea). This allowed us to establish trends across the nesting season to determine whether these physiological parameters indicate if leatherbacks forage or fast while on nesting grounds. Using the biuret method and agarose gel electrophoresis, total serum protein (median = 5.0 g/dl) and protein fractions were quantified and include pre-albumin (median = 0.0 g/dl), albumin (median = 1.81 g/dl), α1-globulin (median = 0.90 g/dl), α2-globulin (median = 0.74 g/dl), total α-globulin (median = 1.64 g/dl), β-globulin (median = 0.56 g/dl), -globulin (median = 0.81 g/dl) and total globulin (median = 3.12 g/dl). The albumin:globulin ratio (median = 0.59) was also calculated. Confidence intervals (90%) were used to establish reference intervals. Total protein, albumin and total globulin concentrations declined in successive nesting events. Protein fractions declined at less significant rates or remained relatively constant during the nesting season. Here, we show that leatherbacks are most likely fasting during the nesting season. A minimal threshold of total serum protein concentrations of around 3.5–4.5 g/dl may physiologically signal the end of the season's nesting for individual leatherbacks. The results presented here lend further insight into the interaction between reproduction, fasting and energy reserves and will potentially improve the conservation and management of this imperiled species.
PubDate: 2014-02-19T23:47:45-08:00
DOI: 10.1093/conphys/cou002|hwp:master-id:conphys;cou002
Issue No: Vol. 2, No. 1 (2014)
- One fledgling or two in the endangered Carnaby's Cockatoo (Calyptorhynchus
latirostris): a strategy for survival or legacy from a bygone era'
Authors: Saunders, D. A; Mawson, P. R, Dawson, R.
Pages: cou001 - cou001
Abstract: Of the five species of black cockatoo in the genus Calyptorhynchus, those species with red tail bands (Red-tailed Black Cockatoo and Glossy Black Cockatoo) lay clutches of only one egg and those with white or yellow tail bands (Carnaby's Cockatoo, Baudin's Cockatoo and Yellow-tailed Black Cockatoo) usually lay clutches of two. The breeding of the endangered Carnaby's Cockatoo has been studied from 1969 to 2012 at a number of localities throughout its range in south-western Australia within a region largely cleared for agriculture. When raising nestlings the species feeds on seeds of native vegetation, and there was a strong but not significant negative relationship between nesting success and percentage loss of native vegetation within 6 and 12 km of nest hollows. There was a significant negative relationship between the health of nestlings and percentage loss of native vegetation around nest hollows. While the usual clutch size is two, average clutch size tended to be lower in areas where much native vegetation has been cleared. While both eggs hatch in 77% of two-egg clutches, the species normally fledges only one young. However, the species is capable of fledging both nestlings from a breeding attempt. Sets of siblings are usually the product of older, more experienced females nesting in areas where more native vegetation has been retained. The conservation implications of these findings are discussed in the light of predicted changes to the climate of south-western Australia.
PubDate: 2014-02-17T06:29:58-08:00
DOI: 10.1093/conphys/cou001|hwp:master-id:conphys;cou001
Issue No: Vol. 2, No. 1 (2014)
- Linking physiological approaches to marine vertebrate conservation: using
sex steroid hormone determinations in demographic assessments
Authors: Labrada-Martagon, V; Zenteno-Savin, T, Mangel, M.
Pages: cot035 - cot035
Abstract: Sex, age and sexual maturation are key biological parameters for aspects of life history and are fundamental information for assessing demographic changes and the reproductive viability and performance of natural populations under exploitation pressures or in response to environmental influences. Much of the information available on the reproductive condition, length at sexual maturity and sex determinations of endangered species has been derived from direct examination of the gonads in dead animals, either intentionally or incidentally caught, or from stranded individuals. However, morphological data, when used alone, do not provide accurate demographic information in sexually monomorphic marine vertebrate species (e.g. sharks, sea turtles, seabirds and cetaceans). Hormone determination is an accurate and non-destructive method that provides indirect information about sex, reproductive condition and sexual maturity of free-ranging individuals. Correlations between sex steroid concentrations and biochemical parameters, gonadal development and state, reproductive behaviour and secondary external features have been already demonstrated in many species. Different non-lethal approaches (e.g. surgical and mark–recapture procedures), with intrinsic advantages and disadvantages when applied on free-ranging organisms, have been proposed to asses sex, growth and reproductive condition. Hormone determination from blood samples will generate valuable additional demographic information needed for stock assessment and biological conservation.
PubDate: 2014-02-11T06:45:10-08:00
DOI: 10.1093/conphys/cot035|hwp:master-id:conphys;cot035
Issue No: Vol. 2, No. 1 (2014)
- Hooking injury, physiological status and short-term mortality of juvenile
lemon sharks (Negaprion bevirostris) following catch-and-release
recreational angling
Authors: Danylchuk, A. J; Suski, C. D, Mandelman, J. W, Murchie, K. J, Haak, C. R, Brooks, A. M. L, Cooke, S. J.
Pages: cot036 - cot036
Abstract: Sport fishing for sharks, including fishing with the intent to release, is becoming more prevalent within the recreational angling community. Common targets of recreational anglers are juvenile lemon sharks (Negaprion brevirostris) that frequent shallow tropical nearshore habitats. In this study, we captured 32 juvenile lemon sharks (530–875 mm total length) with conventional angling gear (i.e. spinning rods, dead fish bait and 5/0 barbed circle hooks) from the coastal waters of Eleuthera, The Bahamas, to determine the consequences of capture for individual sharks. Each shark was examined for hooking injuries, blood sampled to quantify physiological disturbance, assessed for reflex impairment and then monitored to assess post-release behaviour and mortality. Four sharks (12.5%) died following release during the 15 min tracking period. Principal components (PC) analysis revealed four axes describing 66.5% of the variance for blood physiology parameters, total length and water temperature. The PC1 and PC3 scores, characterized by positive factor loadings for indicators of exercise-induced stress and blood ion concentrations, respectively, were significantly related to fight time but were not associated with short-term mortality. Short-term mortality was significantly related to factor scores for PC4 that loaded heavily for water temperature and total length. Ten sharks (31%) exhibited impaired reflexes, with loss of bite reflex being most prevalent. Sharks that died had the following characteristics: (i) they had two or more impaired reflexes; (ii) they were hooked in the basihyal; (iii) they exhibited no movement after the initial bout of directional swimming; and (iv) they experienced high water temperatures (i.e. >31°C). Collectively, these results indicate that for juvenile lemon sharks inhabiting tropical flats, fight time can influence the degree of physiological disturbance, while water temperature contributes to the likelihood of survival following release.
PubDate: 2014-02-05T06:16:09-08:00
DOI: 10.1093/conphys/cot036|hwp:master-id:conphys;cot036
Issue No: Vol. 2, No. 1 (2014)
- A practical field extraction method for non-invasive monitoring of hormone
activity in the black rhinoceros
Authors: Edwards, K. L; McArthur, H. M, Liddicoat, T, Walker, S. L.
Pages: cot037 - cot037
Abstract: Non-invasive hormone analysis is a vital tool in assessing an animal's adrenal and reproductive status, which can be beneficial to in situ and ex situ conservation. However, it can be difficult to employ these techniques when monitoring in situ populations away from controlled laboratory conditions, when electricity is not readily available. A practical method for processing faecal samples in the field, which enables samples to be extracted soon after defaecation and stored in field conditions for prolonged periods prior to hormone analysis, is therefore warranted. This study describes the development of an optimal field extraction method, which includes hand-shaking faecal material in 90% methanol, before loading this extract in a 40% solvent onto HyperSep™ C8 solid-phase extraction cartridges, stored at ambient temperatures. This method was successfully validated for measurement of adrenal and reproductive hormone metabolites in faeces of male and female black rhinoceros (Diceros bicornis) and was rigorously tested in controlled laboratory and simulated field conditions. All the hormones tested demonstrated between 83 and 94% and between 42 and 89% recovery of synthetic and endogenous hormone metabolites, respectively, with high precision of replication. Furthermore, results obtained following the developed optimal field extraction method were highly correlated with the control laboratory method. Cartridges can be stored at ambient (cool, dry or warm, humid) conditions for periods of up to 6 months without degradation, before re-extraction of hormone metabolites for analysis by enzyme immunoassay. The described method has great potential to be applied to monitor faecal reproductive and adrenal hormone metabolites in a wide variety of species and allows samples to be stored in the field for up to 6 months prior to analysis. This provides the opportunity to investigate hormone relationships within in situ populations, where equipment and facilities may previously have been limiting.
PubDate: 2014-02-04T04:14:34-08:00
DOI: 10.1093/conphys/cot037|hwp:master-id:conphys;cot037
Issue No: Vol. 2, No. 1 (2014)
- Impacts of environmental pressures on the reproductive physiology of
subpopulations of black rhinoceros (Diceros bicornis bicornis) in Addo
Elephant National Park, South Africa
Authors: Freeman, E. W; Meyer, J. M, Bird, J, Adendorff, J, Schulte, B. A, Santymire, R. M.
Pages: cot034 - cot034
Abstract: Black rhinoceros are an icon for international conservation, yet little is known about their physiology due to their secretive nature. To overcome these challenges, non-invasive methods were used to monitor rhinoceros in two sections of Addo Elephant National Park, South Africa, namely Addo and Nyathi. These sections were separated by a public road, and the numbers of elephants, predators and tourists were higher in Addo. Faecal samples (n = 231) were collected (from July 2007 to November 2010) from known individuals and analysed for progestagen and androgen metabolite (FPM and FAM, respectively) concentrations. As biotic factors could impact reproduction, we predicted that demographics, FPM and FAM would vary between sections and with respect to season (calendar and wet/dry), climate and age of the rhinoceros. Mean FPM concentrations from pregnant females were seven times higher (P
PubDate: 2014-02-04T04:14:34-08:00
DOI: 10.1093/conphys/cot034|hwp:master-id:conphys;cot034
Issue No: Vol. 2, No. 1 (2014)
- Conservation physiology today and tomorrow
Authors: Cooke; S. J.
Pages: cot033 - cot033
PubDate: 2014-01-07T02:20:52-08:00
DOI: 10.1093/conphys/cot033|hwp:master-id:conphys;cot033
Issue No: Vol. 2, No. 1 (2014)