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On-line version ISSN 2071-0771
Print version ISSN 0075-6458
Koedoe vol.54 n.1 Pretoria Jan. 2012
Climate and vegetation in a semi-arid savanna: Development of a climate-vegetation response model linking plant metabolic performance to climate and the effects on forage availability for large herbivores
Armin H. SeydackI; Cornelia C. GranII; Izak P. SmitII; Wessel J. VermeulenI; Johan BaardI; Nick ZambatisII
IScientific Services, Garden Route National Park, South African National Parks, South Africa
IIScientific Services, Kruger National Park, South African National Parks, South Africa
A framework to establish the expected effects of climate on forage quantity and quality in a local savanna system was developed to interpret large herbivore population performance patterns in the Kruger National Park. We developed a climate-vegetation response model based on interpretation and synthesis of existing knowledge (literature review) and supported by investigation and analyses of local patterns of climate effects on forage plant performance and chemical composition.
Developing the climate-vegetation response model involved three main components, namely (1) defining indicators of forage availability to herbivores (nitrogen productivity, nitrogen quality, carbon-nutrient quality), (2) identifying herbivore species guilds of similar nutritional requirements with respect to these indicators [bulk feeders with tolerance to fibrous herbage (buffalo, waterbuck), bulk feeders with preference for high nitrogen quality forage (short grass preference grazers: blue wildebeest and zebra) and selective feeders where dietary items of relatively high carbon-nutrient quality represented key forage resources (selective grazers: sable antelope, roan antelope, tsessebe, eland)] and (3) developing a process model where the expected effects of plant metabolic responses to climate on key forage resources were made explicit.
According to the climate-vegetation response model both shorter-term transient temperature acclimation pulses and longer-term shifts in plant metabolic functionality settings were predicted to have occurred in response to temperature trends over the past century. These temperature acclimation responses were expected to have resulted in transient pulses of increased forage availability (increased nitrogen- and carbon-nutrient quality), as well as the progressive long-term decline of the carbon-nutrient quality of forage.
CONSERVATION IMPLICATIONS: The climate-vegetation response model represents a research framework for further studies contributing towards the enhanced understanding of landscape-scale functioning of savanna systems with reference to the interplay between climate, vegetation and herbivore population dynamics. Gains in such understanding can support sound conservation management.
Herbivore population trends in the Kruger National Park (KNP) over the past century were traditionally explained with reference to decimation by hunting and epizootics (Joubert 2007a; Pienaar 1963), effects of rainfall (Dunham, Robertson & Grant 2004; Owen-Smith & Ogutu 2003; Whyte & Joubert 1988) and predation (Harrington et al. 1999; Joubert 2007a, 2007b; Owen-Smith, Mason & Ogutu 2005; Owen-Smith & Mills 2006; Owen-Smith & Mills 2008). However, the long-term and spatially widespread nature of population trends suggested that over-arching landscape-scale influences may also be involved to an as yet unknown extent. A greater role of climate effects as a long-term landscape-scale factor was therefore implicated. Accordingly, we initiated a study to explore the extent to which climate-vegetation responses could plausibly explain diverse and divergent spatiotemporal patterns in population performance of eight large herbivore species, namely African buffalo (Syncerus caffer), blue wildebeest (Connochaetes taurinus), plains zebra (Equus burchelli), waterbuck (Kobus ellipsiprymnus), sable antelope (Hippotragus niger), roan antelope (Hippotragus equinus), tsessebe (Damaliscus lunatus lunatus) and eland (Taurotragus oryx).
To interpret large herbivore population performance patterns over space and time in relation to climate it was necessary to develop a framework in which the expected effects of climate on forage quantity and quality were established. Towards this purpose we developed a climate-vegetation response model. This model was developed through interpretation and synthesis of existing knowledge (literature review) and supported by analyses of local patterns of climate effects on forage plant performance and chemical composition. Forage availability to herbivores was taken to be a function of plant productivity and the nutritional quality of the resultant plant material (Fryxell 1991; Holdo, Holt & Fryxell 2009), based on concentrations of protein (nitrogen), non-structural carbohydrates (TNC) and minerals in plant tissues. Key resources for herbivores thus relate to nitrogen productivity, nitrogen quality and carbon-nutrient quality. A central notion of the climate-vegetation response model is that levels of these three forage resource indicators are affected differentially by plant metabolic processes in response to the nature of edaphoclimatic resources (water, temperature and nutrients) available to plants. To the extent that different herbivore species have divergent nutritional requirements in respect of these key forage resources, we expected that their population performances would be affected differentially by conditions of the edaphoclimatic environment (spatial scale) and climate (temporal scale).
The climate-vegetation response model developed here accordingly consists of three main components:
definition of indicators of forage availability to herbivores (nitrogen productivity, nitrogen quality and carbonnutrient quality)
identification of herbivore species guilds of similar nutritional requirements in respect of these indicators
development of a climate-plant metabolic response process model where the expected effects of plant metabolic responses to climate on key forage resources are made explicit.
With the climate-vegetation response model as explanatory framework, large herbivore population performance patterns in both space and time in the KNP were investigated and interpreted (Seydack et al. 2012). In a broader sense, however, our climate-vegetation response model is intended to represent a research framework for further studies contributing towards the enhanced understanding of landscape-scale functioning of savanna systems in respect of the interplay between climate, vegetation and herbivore population dynamics.
Study area
The KNP is situated in north-eastern South Africa and represents a large (approximately 2 000 000 ha) semi-arid savanna system. The area lies between the Drakensberg escarpment in the west and the Mozambique coastal plain in the east. Covering an altitudinal range of between 200 m a.s.l. and 700 m a.s.l., the KNP falls within two disparate climate zones as defined by the South African Weather Service (Venter, Scholes & Eckhardt 2003). The area north of the Olifants River is in the northern arid bushveld zone, receiving 300 mm - 500 mm rain per year, whilst the southern part of the park falls into the lowveld bushveld zone, with an average annual rainfall of 500 mm - 700 mm per year. Years of pronounced below-average rainfall were 1963-1964, 1973, 1983-1984, 1987, 1991-1992 and 1998 (Figure 1). Growing season duration (v. Schulze 1997) is on average about 1.5 months shorter in the north than in the south (96 days compared with 142 days, respectively).
Temperature records from stations within or near the KNP followed trends congruent with those recorded globally (Figures 2 and 3). Three phases of temperature increases were discernable. The first reached peak values between 1937 and 1947, followed by a second phase of increasing temperature towards the period 1958-1960 and a third, still ongoing, warming phase which commenced between 1975 and 1978. Locally differentiated temperature trends are shown in Figure 3. Regional temperature lapse rates for monthly means of daily maximum and minimum temperatures are -0.777 ºCx100 m-1 and -0.465 ºCx100 m-1, respectively (Schulze 1995). As indicated by higher summerto-winter heat unit differentials (determined according to Schulze 1997), northern areas of the park experience more pronounced temperature seasonality.
The park is longitudinally divided into granitic substrates forming relatively nutrient-poor sandy soils in the west and more nutrient-rich, basalt-derived clay soils in the east (Venter et al. 2003). The savanna vegetation on nutrient-poor substrates tends to be dominated by trees of Combretaceae (e.g. Combretum and Terminalia species) and Caesalpineaceae, whereas those on more nutrient-rich clay soils are dominated by trees of Mimosaceae (especially Acacia species) (Gertenbach 1983; Venter et al. 2003). The vegetation of the northern KNP is characteristically dominated by mopane (Colophospermum mopane) and this species is well represented in broad-leaved bushveld vegetation types on granites and broad-leaved shrubveld associated with basalts (Gertenbach 1983; Venter et al. 2003). The herbaceous layer of the KNP is dominated by C4 grass species (Kennedy, Biggs & Zambatis 2003) and the more nutrient-rich savanna vegetation types on clay soils carry dense stands of nutritious, high-bulk grasses (Venter et al. 2003).
Materials and methods
Development of an explanatory framework
Exploration of spatiotemporal patterns in population performance of eight large herbivore species revealed three population performance response groups (i.e. groups of large herbivore species that shared broad-scale habitat preferences and similar population performance trends over time) and group-specific correlations with climate variables (Seydack et al. 2012). We developed an explanatory framework - the climate-vegetation response model - which permits the interpretation of these correlative patterns in relation to climate effects. As part of the climate-vegetation response model we (1) defined indicators of forage availability (quantity and quality), (2) established forage selection requirements characteristic of and unique to the three herbivore population performance response groups (nutritional guilds), and (3) developed a plant-climate response process submodel. The resulting climate-vegetation response model defined the expected effects of climate on indices of forage availability, thereby providing an explanatory framework for the interpretation of spatiotemporal patterns in herbivore population performance in relation to climate. The model was developed largely based on the interpretation and synthesis of relevant literature. Some results of local research contributed towards the definition of key forage resource indices.
Definition of indicators of forage quantity and quality
Leaf and stem material of the grass species Panicum maximum, Panicum coloratum and Themeda triandra were collected in and beyond the roan enclosure (Nwashitshumbe, northern KNP) during September 2007, November 2007, August 2008 and February 2009. The apical 20 cm of grass stems were collected as samples of stem material. The samples originated from a study to explore the effects of fire frequency on forage quality, where sampling was undertaken in four treatment blocks (three inside and one outside of the enclosure) defined by the time since the last burn. Each treatment block contained three sampling localities (replications) to represent a total of 12 samples per sampling event.
The collected grass material was dried at 55 ºC overnight and mill ground through a 1-mm sieve to form homogeneous powdered samples. The concentrations of ash minerals and TNC were determined, as well as in vitro organic matter digestibility (OMD) of the powdered sample material. These analyses were performed by the Analytical Services department of the Agricultural Research Council (ARC) in Irene. Ashing was performed in a furnace at 600 ºC. TNC were analysed as reducing sugars after complete enzymatic hydrolysis to monosaccharides. The method entailed gelatinisation of all starch in the sample by autoclaving, followed by enzymatic hydrolysis of the starch to glucose and determination of glucose content by spectrometric measurement. Duplicate results were within 3% of the mean for each pair. In vitro OMD was determined following an adaptation of the two-phase technique described by Tilley and Terry (1963), with some modification introduced by Engels and Van der Merwe (1967). It involved a 24-hourlong fermentation by rumen micro-organisms in a buffer solution followed by a 48-hour-long pepsin digestion after acidification. The reduction in the organic matter content was ascribed to digestion of the sample. For the determination of 813C and 815N, samples were combusted in an automated Thermo1112 Elemental Analyser (Carlo Erba, Milan). The resultant CO2 and N2 gases were then introduced to a Thermo Delta stable light isotope XP mass spectrometer via a continuous flow-through inlet system (Thermo Conflo III). 13C/12C and 15N/14N ratios were expressed in the delta (8) notation in parts per thousand ( ) relative to international standards (Pee Dee Belemnite standard for carbon; N2 air for nitrogen). Standard deviations of repeated measurements were less than 0 . 1 for 81 3C (Stable Light Isotope Unit, Department of Archaeology, University of Cape Town).
Grass sample collections during November 2007 and February 2009 represented spring and summer sampling events, respectively, and plant growth under conditions of concurrent high levels of temperature and water availability (TW conditions). Dry-season grass and stem material collected during September 2007 had been subject to summer greening in November-December 2006 (TW metabolic cueing at sub-mature stages; mean monthly maximum and minimum temperatures at 33.9 ºC and 21.1 ºC, respectively) and water-stressed summer growth conditions (Tw growth realisation at mature stages). Dry-season material collected in August 2008 represented conditions following spring greening in September-October 2007 (tw metabolic cueing at sub-mature stages; mean monthly maximum and minimum temperatures at 30.6 ºC and 17.7 ºC, respectively) and summer growth subject to high rainfall conditions (TW growth realisation at mature stages). The main objective of this part of the study was to determine how these varying growth conditions affected the chemical composition and digestibility of the grass tissues and the implications for key indices of forage quality defined in the context of this study.
Climate-vegetation response model
Indicators of forage availability
Nitrogen productivity: Nitrogen productivity is defined as the quantitative availability of forage items for herbivores of a given nitrogen quality (plant protein content) as a result of biomass production. Grass productivity is known to be strongly promoted by water availability [positively correlated with rainfall (Zambatis 2004)] and temperature, especially in the case of tropical grass species (Long 1999; Luo 2007; Wan et al. 2005), which have high temperature optima for growth (Dwyer et al. 2007; 't Mannetje 1982; Tudsri, Matsuoka & Kobashi 2002; Wilson & Ford 1971). Warminginduced increases in biomass production of C grasses have been demonstrated under experimental conditions (An et al. 2005; Bijoor et al. 2008). Accordingly, nitrogen productivity of C4 grasses and subtropical woody vegetation is expected to increase over time as ambient temperature increases (Figure 2). However, at progressively higher nitrogen productivity, an inverse relationship to nitrogen quality due to nitrogen dilution is generally encountered (An et al. 2005; Fryxell 1991; Fryxell et al. 2005; Mutanga et al. 2004; Wilson 1982).
Nitrogen quality: High nitrogen quality of forage implies high nitrogen concentrations of plant tissues; that is, plant protein content not unduly diluted by structural or nonstructural carbon and of relatively high digestibility. An index of nitrogen quality is defined here as the product of nitrogen concentration and OMD of the plant tissues involved. Wetseason nitrogen quality tended to be higher early in the wet season (spring) compared with later in the wet season (summer) (Figure 4c). Nitrogen content in summer leaf material (SUL) was diluted by structural carbon relative to that of spring (SPL) leaf material (analysis of variance for carbon content, followed by a post hoc Bonferroni test showed SUL > SPL; p < 0.00001) and carbon-nutrient levels (Figure 4d: SUL > SPL). This is congruent with nitrogen dilution through growth under conditions of relatively high temperature and water availability (TW conditions), as typically experienced by tropical grasses (Wilson & Ford 1971).
Dry-season leaf (WL) and stem (WS) material were sampled to represent two sets of conditions (Figure 4): summer greening and water-stressed summer growth (WL-Su/WS-Su) and spring greening and summer growth with high rainfall (WL-Sp/WS-Sp), respectively. Nitrogen quality of dryseason WL and WS material (Figure 4c) was enhanced following water-stressed summer growth (WL-Su/WS-Su: Figure 4b; Tw conditions indicated by low 815N values) compared with such material following summer growth in higher rainfall conditions (WL-Sp/WS-Sp: Figure 4a; TW conditions indicated by high 815N values; N-quality: leaf material: F = 113.36, n = 72, p < 0.000001; stem material: F = 50.77, n= 72, p < 0.000001). OMD of dry-season grass tissue (both leaf and stem material) following water-stressed summer growth (Tw conditions; Figure 4b) was significantly higher than of dry-season material following summer growth under TW conditions (Figure 4a; OMD: ANOVA: Bonferroni post hoc test: WL-Su > WL-Sp; p < 0.0001; WS-Su > WS-Sp: p < 0.00001). OMD of dry-season grass leaf material was positively related to nitrogen content and negatively correlated with 815N values (multiple regression of OMD on N and 815N: fi of N = +0.758; fi of 815N = -0.348, R2 = 0.42, n = 72). According to the results of Codron et al. (2005) seasonal shifts in plant 815N corresponded positively with seasonal summer rainfall, supporting our interpretation that 815N values index summer growth activity under TW conditions. These relationships are consistent with general findings that metabolic activity under water stress promotes digestibility (Wilson 1982) and that high growth activity under TW conditions results in reduced forage quality. Metabolic activity under conditions of high temperature and water availability (TW conditions) is expected to negatively affect dry matter digestibility as it promotes more rapid growth and stem development of, particularly, tropical grasses ('t Mannetje 1975; Wilson 1982; Wilson, Taylor & Dolby 1976). High growth temperatures also hasten the maturation of individual tissues and the digestibility of plant tissue is usually higher when grown at low temperatures, such as in spring or winter ('t Mannetje 1984; Wilson 1982).
Carbon-nutrient quality:Carbon-nutrient quality of forage items is defined here as the product of TNC and ash mineral concentrations (Figure 4d). Dry-season TNC content of grass leaf material following spring greening was significantly higher than that of leaf material following summer greening (dry-season TNC content: WL-Sp > WL-Su; F = 25.02, p < 0.00001). A similar pattern was found for ash (mineral) contents (ANOVA, followed by post hoc Bonferroni test: WL-Sp > WL-Su and WS-Sp > WS-Su, p < 0.00001). These results are consistent with a metabolic response mode of low-temperature growth during spring (tw metabolic cueing at sub-mature stages) resulting in storage allocation of TNC (Estiarte & Penuelas 1999; Herms & Mattson 1992; Wilson 1975) and of minerals (Balasko & Smith 1971). In accordance with these findings, high carbon-nutrient quality was typically encountered in dry-season leaf material (Figure 4d) and was higher in dry-season leaf and stem tissue in grass cohorts that had been subject to spring greening (Figure 4d; ANOVA followed by a post hoc Bonferroni test: WL-Sp > WL-Su, p < 0.00001; WS-Sp > WS-Su, p < 0.00001). Carbon-nutrient quality forage items are thus characterised by relatively high concentrations of TNC and ash minerals resulting from substantial metabolic allocation to storage under circumstances promoted by constrained growth (particularly owing to low temperatures, but also moisture stress: tw conditions) but sustained photosynthesis.
Carbon-nutrient quality of dry-season plant leaf and stem material of T. triandra (Andropogoneae) was generally higher than for the two species of Paniceae (Figure 4d; ANOVA and post hoc Bonferroni tests: p < 0.01). This reflected the predisposition of andropogonoid species, geared to cope with more pronounced seasonality (Osborne 2008), towards greater metabolic scope for storage investment. The typical accumulation of tannin-like substances in the foliage of Andropogoneae indicates a carbon excess metabolism with pronounced allocation to storage (Baas 1989; Herms & Mattson 1992). Such physiological characteristics are considered adaptive to ensure sustained metabolic performance under seasonally variable conditions of resource availabilities (temperature and water: tW/Tw/tw conditions). All species of Andropogoneae function according to the NADP-ME biochemical subtype and these are implicated to operate at lower temperature optima than species of the other subtypes, including, inter alia, species of Paniceae (Ehleringer, Cerling & Helliker 1997). Grass species of this biochemical subtype, and particularly of Andropogoneae, also exhibited the smallest responses to changes in environmental conditions (Buchmann et al. 1996). These findings are suggestive of the capacity of Andropogoneae species for sustained metabolic performance at variable and lower resource levels (dryseason growth), underpinning their metabolic scope for storage of metabolites (TNC and minerals for enhanced carbon-nutrient quality).
Herbivore species guilds of key nutritional requirements
In this section we present evidence suggesting that herbivore species within particular population performance response groups share similar broad-scale forage selection requirements. Buffalo and waterbuck are considered roughage feeders able to digest fibrous food relatively efficiently (Hofmann 1973, 1989). Despite the relatively unselective bulk grazing habit of buffalo, they adjust their feeding patterns in relation to seasonally changing forage quantity and quality (Macandza, Owen-Smith & Cross 2004). However, for both these species food quantity seems to override exacting quality requirements. This is in contrast to blue wildebeest and zebra, which have clear preferences for short-grass areas on nutrient-rich soils (Grange & Duncan 2006; Traill 2004). Both species select grass patches of high nitrogen quality for feeding, although zebra, as a hindgut fermenter, can tolerate more fibrous and longer-grass feeding conditions (Bodenstein, Meissner & Van Hoven 2000; Smuts 1972).
Apart from species-specific, often seasonally changing, feeding preferences (Dunham et al. 2004; Heitkonig & Owen-Smith 1998; Joubert & Bronkhorst 1977; Magome et al. 2008; Watson & Owen-Smith 2000), all four selectively feeding species (i.e. tsessebe, eland, sable and roan antelope) are able to adapt to a wide range of grass heights and often include medium to tall grasses in their diets (Joubert 1976; Skinner & Chimimba 2005; Traill 2004). According to a study by Parrini (2006) sable antelope do not avoid stemmy grass tufts and include tall stemmy species generally avoided by short-grass grazers. Sable antelope were found to be particularly tolerant of stems in habitats with intermediate to high nutrient levels. Heitkonig and Owen-Smith (1998) found a similar pattern in roan antelope, which tolerated stems when leaf quality was high. The preferred feeding sites of tsessebe typically have soils with a high clay content (Dorgeloh 2006). Topi (Damaliscus lunatus jimela), with foraging habits believed to be similar to those of tsessebe, selected for the tallest plants and species with relatively long leaves when feeding on grass with more than 20% green leaves (Duncan 1975 op. cit. Parrini 2006). These patterns of ingesting stem material together with leaf matter and the relatively high importance of nutrient contents of these are commensurate with the maintenance of relatively high dietary TNC and mineral nutrient levels resulting in carbon-nutrient ratios as required for sustained carbon-nutrient quality.
Numerous studies have revealed the prominence of andropogonoid grass species in the preferred habitat and forage species assemblages of sable antelope (Le Roux 2010; Magome 1991; Parrini 2006), roan antelope (Joubert 1976; Van Lavieren & Esser 1979), tsessebe (Gureja & Owen-Smith 2002) and eland (Watson & Owen-Smith 2000). As indicated in the previous section, andropogonoid grass species would tend towards a sustained metabolic performance type metabolism and thus have a propensity towards carbon and nutrient storage, particularly when subject to seasonally low temperature conditions. Under such metabolically favourable conditions, these species are expected to have high carbonnutrient quality; that is, a combination of favourable levels of TNC, nitrogen and minerals. All these features of forage selectivity, including tolerance of stemminess, prominence of andropogonoid grass species, adaptability to a wide range of grass heights and, in the case of browsing, feeding on freshly fallen TNC-rich leaves [see Skinner & Chimimba (2005) for reference to eland] indicate that these species can be classed as selective feeders of plant parts of relatively high carbonnutrient quality. In summary, the eight species studied here are grouped into three guilds of nutritional requirements: bulk feeders with tolerance to fibrous herbage (buffalo and waterbuck), bulk feeders with preference for high nitrogen quality (short-grass grazers: blue wildebeest and zebra) and selective feeders for which dietary items of relatively high carbon-nutrient quality are of particular importance (selective grazers: sable antelope, roan antelope, tsessebe and eland).
Plant-climate response processes
Plant metabolic performance trade-off relationships: Owing to resource limitations plants are subject to trade-offs between growth, maintenance, storage, reproduction and defence (Herms & Mattson 1992). Consequently, there are, inter alia, strong inverse relationships between the functional allocation to growth and non-growth processes, notably carbon storage (Herms & Mattson 1992). Accordingly, there is an allocation trade-off between quantity of plant tissue produced through growth (structural plant content) and quality, represented by the proportion of non-structural plant content (metabolically active components and storage products). Thus, abundance of resources such as water, nutrients and temperature enhance productivity, but increasing productivity then progressively reduces plant tissue quality for herbivores through nutrient dilution (An et al. 2005; Dwyer et al. 2007; 't Mannetje 1982, 1984; Tudsri et al. 2002; Van Soest, Mertens & Deinum 1978; Wilson & Ford 1971; Wilson 1982), reduction in digestibility ('t Mannetje 1975, 1984; Van Soest et al. 1978; Wilson & Ford 1973; Wilson & 't Mannetje 1978) and reduced allocation to storage (low TNC content) (Estiarte & Penuelas 1999; Herms & Mattson 1992; Van Soest et al. 1978).
The climate-vegetation response model was developed to integrate existing knowledge and to form part of an explanatory template for spatiotemporal patterns of climatevegetation response processes controlling forage quantity and quality. At the core of this model is the metabolic performance trade-off model, from which predictions can be made regarding divergent plant responses to site and climate-linked resource constraints and their impact on parameters of forage availability to herbivores. The principal trade-off in the context of this model is between maximised peak performance, closely tracking and responsive to conditions of resource surplus (RMP; resource responsive metabolic performance mode), and sustained performance when subject to conditions of varying resource levels or deficits (SMP; sustained metabolic performance mode). The capacity for maximum metabolic performance under conditions of resource surplus is at the cost of the capacity for sustained performance under conditions of resource deficits or fluctuations. In line with this reasoning, we expect a propensity towards the RMP mode under conditions of high and less fluctuating levels of temperature and water availability (TW conditions: combination of relatively high and sustained levels of water and temperature during the growing season), whereas under conditions of fluctuating resource levels and pronounced deficits (regarding temperature and water; tW or Tw conditions), the SMP mode would be expected to predominate.
High peak-level performance characteristics of the RMP mode require high turnover metabolism (capacity for high instantaneous rates of photosynthesis; Amax). This is generally associated with high foliar nitrogen levels (Lambers, Chapin & Pons 1998) resulting in increased nitrogen/carbon ratios of plant tissues. In contrast, sustained performance capacity of the SMP mode requires resource use efficiency and is associated with the propensity towards somatic accumulation [size, storage, longevity: relatively high carbon/nitrogen ratios of plant tissues; Herms and Mattson (1992)]. Furthermore, stress-tolerant plants (SMP mode) tend to allocate an especially high proportion of available energy to maintenance respiration required to tolerate adverse environmental conditions (Taylor 1989). Plants in a relative SMP mode are accordingly expected to be even more sensitive to resource conditions inducing elevated maintenance respiration, such as increased mean mimimum temperature (reflecting nocturnal temperature conditions) (T min). Resource constraints on growth are generally more intense than their inhibitory effect on photosynthesis. As a consequence of carbon acquisition exceeding growth requirements, the products of photosynthesis accumulate, primarily as carbohydrate storage products (Baas 1989; Herms & Mattson 1992; Lambers & Poorter 1992). When tracking resource surplus conditions favourable for both photosynthesis and growth in RMP-mode plants, the resource-level response relationships for growth and photosynthesis tend to be similar (Wilson & Ford 1973). In SMP-mode plants, stress tolerance capacity is associated with photosynthesis being relatively less sensitive to resource levels than growth. Accordingly, there is greater scope for source (photosynthesis) to sink (growth) imbalance in SMP mode plants, favouring allocation to secondary metabolism and storage as carbon assimilation levels exceed those which are required for growth. Plants in relative SMP mode are thus comparatively stress tolerant in order to cope with fluctuations in resource levels. As such their metabolism is capable of functioning at relatively low temperature and water availability levels/optima (broad metabolic amplitude; SMP-tw functional efficiency). Such metabolic capacity is, however, associated with relatively high storage-to-growth allocation priority and comparatively high maintenance respiration costs (i.e. temperature sensitivity). In contrast, plants in relative RMP mode are geared to the maximum use of resource surplus conditions, functioning at relatively high temperature and water resource level optima (narrow metabolic amplitude) and high growth-to-storage priority (Figure 5).
Plant metabolic performance mode settings: The relative expression of SMP to RMP mode functionality/acclimation is a function of the combined availability levels of temperature and water (TW resource conditions). The higher the concurrent and uninterrupted levels of temperature and water available to plants, the more pronounced the intraspecific metabolic adjustment towards higher RMP mode functionality settings. The relative expression of SMP or RMP depends on the spatiotemporal nature of resource availability for plants (water and temperature resource levels and variability or seasonality), shaping forage quantity and quality as a consequence of the relative prevalence of SMP-tW/Tw to RMP-TW functionality (Figure 5). Resource conditions in the northern KNP are characterised by greater moisture stress levels and higher degrees of resource level fluctuations regarding both moisture availability and temperature compared to the southern KNP (increasing north to south rainfall gradient: KNP-north = 483 mm/year; KNP-central = 535 mm/year; KNP-south = 632 mm/year). Growth season duration (v. Schulze 1997) is, on average, about 1.5 months shorter in the northern KNP. According to the metabolic performance trade-off model, we therefore expect the SMP mode to predominate (intraspecifically) in northern KNP areas and the RMP mode to be more prevalent in southern areas of the park. Conditions prevailing in the central KNP are expected to promote an intermediate position in this regard. Conditions for plant functionality are also expected to change along an altitudinal gradient [temperature lapse rates for monthly means of daily maximum and minimum temperatures are -0.777 ºCx100 m-1 and -0.465 ºCx100 m-1, respectively (Schulze 1995)]. A pattern of lower temperatures and increased rainfall at higher altitudes represents tW conditions, with Tw conditions prevailing at lower altitudes. Combining the north-south water availability and altitudinal temperature gradients, plant functionality settings were identified and the associated expected implications for forage quality indicated in accordance with the metabolic performance trade-off model (Table 1).
As a general notion, nitrogen quality is usually considered to be higher in plants on nutrient-rich geological substrates, resulting in higher palatability for herbivores (Skidmore et al. 2010; Venter et al. 2003). This pattern may, however, be modified at various spatial scales by the availability of water (Mutanga et al. 2004) and factors resulting in nitrogen dilution (accentuated SMP or RMP functional expression as in northern and southern KNP, respectively). At a spatial scale we thus generally expect the prevalence of relatively high nitrogen quality forage on nutrient-rich geological substrates in the central KNP (Table 1).
Temperature acclimation and forage quality: Ambient temperature has been increasing over the past century (Figure 2). In particular, Tmin, which represents nocturnal temperature conditions, has increased more steeply than the mean periodic maximum temperature (T ), which represents diurnal temperature conditions (Houghton et al. 1996). Increasing T . is expected to stimulate nocturnal maintenance respiration (Wan et al. 2009), promoting temperature acclimation in order to restore the original steady-state respiration-to-photosynthesis ratio (Dewar, Medlyn & McMurtrie 1999). As temperature increases, leaf metabolic pools adjust until the original steady-state respiration-to-photosynthesis ratio is re-established. Leaf labile carbon, starch and protein pools decrease in response to increased temperature, eventually reaching a new, lower steady state, consistent with the general pattern of plant carbohydrate and soluble protein content being negatively correlated with growth temperature (Dewar et al. 1999; Wan et al. 2009). These acclimation responses represent intraspecific SMP to more RMP functionality shifts (SMP-to-RMP temperature acclimation). This has consequences for forage quality, such as reduced carbohydrate and mineral storage levels (progressively lowered carbon-nutrient quality) and reduced nitrogen quality due to nitrogen dilution and lowered digestibility resulting from high RMP mode-based growth rates (Figure 5).
In the climate-vegetation response model the expression of relative RMP to SMP functionality results from, inter alia, the acclimation to changing temperature conditions. In response to increasing Tmax (daytime temperatures), the productivity of tropical and subtropical forage plants (especially C4 grasses) is increased (Long 1999; Luo 2007; Wan et al. 2005), resulting in greater quantities of plant protein in the landscape (increased nitrogen productivity). Tmax was found to be positively correlated with Tmin (r = 0.52, n = 30, p < 0.004) and negatively correlated with the amounts of summer rainfall (r = 0.54, n = 30, p < 0.003). Phases of relatively elevated Tmax therefore indicate conditions of increased solar radiation (reduced cloud cover) and reduced water availability for plant growth (reduced rainfall). The associated increased photosynthesis-to-growth ratio is conducive to enhanced forage quality (increased storage allocation; reduced nitrogen dilution). During the initial phases of increasing temperature, Tmax is relatively high compared with Tmin and relatively high diurnal temperature ranges are thus encountered, supporting a pulse of enhanced SMP productivity (increased Tmax / Tmin ratio, increased Tmax- Tmin differential, and increased ratio of photosynthesis to respiration). This forms the basis of the first of four defined temperature acclimation phase states (SMP-P, phase of increased SMP productivity) constituting the temperature acclimation sequence resulting from (pulses of) increasing atmospheric temperature (Figure 6). However, as the Tmax / Tmin differential (diurnal temperature range; DTR) declines as nocturnal warming ( Tmin ) increases faster than daytime temperatures, SMP-to-RMP mode acclimation occurs (decreased Tmax / Tmin . ratio, decreased Tmax - Tmin . differential, and increased ratio of respiration to photosynthesis) and sequential temperature acclimation phase states come into effect (Figure 6). The initially enhanced SMP mode productivity declines and RMP-mode growth increases [referred to as over-compensation by Wan et al. (2009)]. The associated shift from SMP-tW/Tw to RMP-TW functionality has physiological consequences which compromise forage quality (Figure 5), notably owing to a shift from storage-based to relative growth-dominated metabolism. This results in a reduction of stored metabolites (TNC, minerals and protein) relative to the accumulation of structural carbon through accelerated growth (reduced carbon-nutrient quality; Figure 5). Furthermore, RMP-TW mode functionality implies metabolic growth activity at higher water and temperature optima. Growth realisation thus takes place under conditions of concurrently high temperature and water availability (TW conditions; at high water and temperature optima), constraining plant productivity under conditions when growth-curbed physiological activity (based on SMP-tw functional efficiency) associated with the production of highquality forage (early morning hours, early in season, dry season growth: SMP-tw functionality) could have occurred. Dry-season rainfall supports SMP-tw functionality, thus promoting the production of forage items of high carbonnutrient and nitrogen quality (Figure 5). However, with progressive SMP-to-RMP acclimation SMP-tw efficiency is expected to decline as RMP-TW functionality favours growth under conditions of higher temperature and water availability. SMP-to-RMP temperature acclimation (shifts from SMP-tW/Tw/tw to RMP-TW functionality) is therefore expected to result in forage with lower nitrogen quality (Figure 5: nitrogen dilution and lowered dry-season forage digestibility) and notably lower carbon-nutrient quality (Figure 5: low metabolic storage allocation priority).
Spatiotemporal interactions in temperature acclimation and functionality settings: Following from the climatevegetation response patterns postulated under the climatevegetation response model we expect pulses of increased forage availability induced by pseudo-cyclic temperature increases and progressive long-term shifts towards increased RMP functionality settings.
Pulses of increased forage availability due to increased productivity of quality forage induced by pseudo-cyclic pulses of temperature increases (Figure 2 and 3: increasing towards 1940; increasing towards 1960; increasing after 1975): In response to transient rising Tmax, pulses of SMP productivity (SMP-P temperature acclimation phase state) occur when the temperature optima for plant functionality are still relatively low (tw metabolic activity). However, as acclimation to Tmin takes effect, increased RMP-TW metabolic activity of plants results in reductions in forage quality and thus forage availability (Figure 6).
Progressive long-term shifts towards relatively advanced RMP functionality settings in response to cumulative acclimation to Tmin and declining diurnal temperature ranges: Trends of progressively deteriorating carbon nutrient quality and increasing nitrogen productivity-tonitrogen quality ratios (Figure 5) over the past century were accordingly anticipated (Figure 2).
Owing to higher and more predictable levels of water availability to plants, such long-term shifts towards higher RMP functionality settings would have taken effect earlier (see Figures 2 and 3, notably in response to prolonged temperature increases between approximately 1930 and 1940-1945) and to more advanced RMP settings in the southern KNP (Table 1). Furthermore, as plants are already functioning at higher RMP settings in the southern KNP, SMP-RMP-SMP temperature response pulses (Figure 6) are expected to be attenuated relative to those in the northern KNP, where pronounced associated pulses of forage availability are expected to be encountered.
Model postulates and predictions
The postulates and predictions inferred from the climatevegetation response model represent an explanatory framework geared to permit, inter alia, the interpretation of herbivore population performance patterns in space and over time. Based on the postulates of this model inferences can be made as to how the metabolic responses of plants to their dynamic edaphoclimatic environment shape forage availability for herbivores by affecting the levels of key forage resources (relating to nitrogen productivity, nitrogen quality and carbon-nutrient quality).
Key forage resources
The climate-vegetation response model differentiates three key indicators affecting forage availability to herbivores: nitrogen productivity, nitrogen quality and carbon-nutrient quality. Nitrogen productivity refers to the quantitative availability of forage items for herbivores of a given nitrogen quality (plant protein content) as a result of biomass production. High nitrogen quality of forage implies high nitrogen concentrations of plant tissues; that is, plant protein content not unduly diluted by structural or non-structural carbon and of relatively high digestibility. Carbon nutrient quality forage items are characterised by relatively high concentrations of non-structural carbohydrates and ash minerals resulting from metabolic allocation to storage under circumstances promoted by constrained growth (low temperatures, moisture stress: tw conditions), but sustained photosynthesis. Levels of these key forage resource indicators in plants (referring primarily to C4 grasses) are determined by plant metabolic responses to the spatiotemporally dynamic availability of resources (temperature, water and nutrients; Figure 5).
Herbivore species guilds of nutritional requirements
As inferred from the nature of the diets of eight large savanna herbivore species, three herbivore species guilds of nutritional requirements were identified: bulk feeders with tolerance to fibrous herbage (buffalo and waterbuck), bulk feeders with preference for high nitrogen quality forage (short-grass grazers: blue wildebeest and zebra) and selective feeders for which dietary items of relatively high carbonnutrient quality represent key forage resources (selective grazers: sable antelope, roan antelope, tsessebe and eland).
Spatial distribution of key forage resources
Plant metabolic adjustments to the north-south water availability and altitudinal temperature gradients are expected to determine the spatial distribution of SMP to RMP functionality settings across the KNP (Table 1). The general pattern involved higher SMP functional expression in the drier, northern areas of the park and at higher altitudes, and advanced RMP functionality settings towards the south. As the SMP mode involves relatively growth-curbed, storagebased metabolism, the availability of forage of enhanced carbon-nutrient quality is accordingly expected to be higher in the northern KNP and at higher altitudes. Metabolic performance responses of intermediate SMP-RMP modes favour lower levels of nitrogen dilution and are associated with forage of relatively high nitrogen quality, especially of plants on nutrient-rich geological substrates (Table 1: central KNP).
Climate-driven temporal trends in forage availability
According to the climate-vegetation response model, both shorter-term transient temperature acclimation pulses (Figures 2 and 3: increasing temperature towards 1940; increasing towards 1960; increasing after 1975 ) and longerterm shifts towards advanced RMP functionality settings are predicted to have occurred in response to temperature trends over the past century (Figure 2). These temperature acclimation responses are expected to have resulted in transient pulses of increased forage availability (increased nitrogen and carbon-nutrient quality; Figure 6), as well as the progressive long-term decline of carbon-nutrient quality of forage and an increasing nitrogen productivity/nitrogen quality ratio associated with advanced RMP functionality settings (Figure 5).
Spatiotemporal interaction in forage availability
Accentuated temperature acclimation responses (Figure 6) are predicted for circumstances where low and unpredictable water availability favour the prevalence of SMP mode settings; that is, in northern relative to southern KNP. More pronounced associated effects on nitrogen quality and carbon-nutrient quality are thus expected towards the northern areas of the park, with attenuation or absence of such responses where relatively high RMP functionality settings already predominate towards the southern KNP.
The climate-vegetation response model as outlined here was applied as an explanatory framework with respect to herbivore population performance patterns in the KNP. Such application resulted in the internally consistent interpretation of spatiotemporal patterns of large herbivore population performance in relation to climate (Seydack et al. 2012).
We acknowledge the effort of rangers, other field staff and scientists in collecting diverse data sets (e.g. animal population censuses and grassland monitoring) over many decades, without which this study would not have been possible. Mss Judith Kruger, Sandra MacFadyen and Sharon Thomson of Scientific Services, KNP, are acknowledged for providing data used in this study. The South African Weather Service provided temperature and rainfall data. This study represents an output of the specialist scientist research programme in systems ecology conducted by members of the Conservation Services Division (Knysna and Skukuza) of South African National Parks. A.H.S, in his capacity as honorary research associate at the Botany Department, University of Cape Town, acknowledges general support received from this institution.
Competing interests
The authors declare that they have no financial or personal relationship(s) which may have inappropriately influenced them in writing this paper.
Authors' contributions
A.H.S. (Garden Route National Park) was responsible for conceptualising and developing the climate-vegetation response model. C.C.G. (Kruger National Park), I.P.S. (Kruger National Park) and N.Z. (Kruger National Park) contributed to in-depth discussions through sharing their knowledge of animal and plant ecology pertaining to the KNP. W.J.V. (Garden Route National Park) acted as field project leader of the research into climate effects on forage quality and J.B. (Garden Route National Park) was involved in data processing.
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Correspondence to:
Armin Seydack
Postal address: PO Box 3542
Knysna 6570, South Africa
Email: firstname.lastname@example.com
Received: 08 Mar. 2011
Accepted: 05 Oct. 2011
Published: 08 Feb. 2012
© 2012. The Authors. Licensee: AOSIS OpenJournals. This work is licensed under the Creative Commons Attribution License.


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The two wheel drive Mitsubishi FGC55K-3 STC in New York is a propane powered vehicle with an articulating boom that has a maximum lifting height of 188 ft. The FGC55K-3 STC can lift up to 12000 pounds.
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ISAs are designed to encourage more of us to save and invest by limiting the amount of tax that can be taken off our investment. We are pleased to be able to offer an ISA so you can keep more of your investment returns – rather than seeing them being taken in tax.
You can choose to invest your Stocks and Shares ISA allowance of £20,000* for the 2017/2018 tax year in our Investment Trust ISA. Invest monthly from only £100 or invest a lump sum from £1,000.
The Aberdeen Investment Trusts ISA offers:
- Minimum monthly investment - £100
- Minimum lump sum investment - £1000
- Low annual charge of £24 (plus VAT) per annum, regardless of how many Aberdeen Investment Trust ISAs you hold
- £15 exit fee per sale + VAT
* The maximum sum for an ISA investment is £20,000 for the current tax year until 5 April 2019.


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Introducing the
Motorized Overhead Storage units by ONRAX
Visit the Ascension series here!
The ONRAX Enduro-Deck system
Onrax overhead garage storage racks, help you turn your clutter into easy-access, out of the way storage. Let us show you how we put our shelving to the test
Are you frustrated by a cluttered or unorganized garage? Storage is the
number one need of dissatisfied garage owners. ONRAX ceiling garage storage racks are the answer for your garage storage needs. You can now transform your
garage into a usable space that you can be proud of. Currently, your garage
ceiling is most likely unused space.
ONRAX overhead garage storage racks can give you up to 112 cubic feet of new
storage space. Other ceiling mounted garage storage products offer lower
quality, less reliable ceiling storage. With ONRAX garage storage, you will
own the premium garage storage racks, boasting a ceiling storage industry
leading 800 pound weight capacity.
The ONRAX Enduro-Deck platform is a patented design created by the
innovative minds of the garage storage industry leaders at ONRAX.
Enduro-Deck is the first garage storage decking product made specifically
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ONRAX launches the Ascesnion Series line of Motorized Overhead Storage
ONRAX celebrates 10 years of producing heavy duty overhead storage racks
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This post originally appeared on the ChicagoNow blog, "Ask Dr. Chill: Practical Answers to the Toughest Caregiving Questions." It is being reposted here with the author's permission.
Alas, I was not able to attend the Alzheimer's Association International Conference in Vancouver this month, but I did follow it closely on the organization's website. The event attracted over 4,300 scientists, physicians and other professionals in the Alzheimer's community who gathered to discuss findings from their most recent batches of research.
If your eyes tend to glaze over when you read news blurbs about complicated research, I don't blame you. The sheer amount of news these days certainly can induce medical information overload.
As an antidote, I offer my Cliff Notes version of the Alzheimer's Association International Conference:
- The conference primarily focused on causes, risk factors, diagnosis, treatment and prevention of the disease.
- A couple of risk factors emerged, including late-life binge drinking, changes in gait (walking patterns) and sleep changes. (Note: A risk factor implies a correlation between the factor and eventual onset of the disease — it does not imply causality. Just because something is associated with something else does not mean that one causes the other.)
- Several treatments showed promise, including experimental drug EVP-6124, intravenous immunoglobulin, medical food Souvenaid, dietary supplement citicoline, and home-based care coordination. (Note: Treatment studies focus on treating the symptoms of Alzheimer's after the disease process is already underway. There is no evidence that any of these treatments are useful for prevention.)
- But on the upside, four different studies indicated that targeted exercise training could reduce the risk of developing dementia among older adults who were either cognitively healthy or only had mild cognitive impairment. (Get moving, folks!)
- Diagnostic advances now allow researchers to better identify people with Alzheimer's when they are still presymptomatic. That's right — early brain changes and subtle cognitive problems can now be detected so that a diagnosis of "preclinical" or "presymptomatic" Alzheimer's disease can be made. Granted, this type of diagnostic accuracy is seen mostly in research settings and has yet to become evident in general medical practice. But what this means is that researchers can now test new drugs among presymptomatic individuals to see if the progression to symptomatic Alzheimer's can actually be prevented.
As I scoured the event's press releases, I felt a combination of hope, pride and sadness wash over me. My hope emerges from the incredible strides taken by the Alzheimer's community that have revealed more about the disease in the past 20 to 30 years than we learned during most of the 20thcentury (Alzheimer's was first identified in 1906). My pride is rooted in the many years I worked for the organization and my first-hand knowledge of its dedication to ultimately finding an end to this wretched disease.
I didn't want to feel sadness, but it's best not to suppress such honest parts of the human experience. My sadness stemmed from my long journey with this disease — both professionally and personally — which has taught me that any measure of hope must be balanced with a healthy dose of realism.
Note that the conference highlighted causes, treatments and prevention — but not cures. We're simply not there yet. We're closer to a cure than ever before, but using that emotionally-laden word more than sparingly is still premature. I applaud the organization for always putting out balanced, accurate reports with no spin or pretense.
So be hopeful, but be realistic, too. And remember that the greatest barrier to the development of better treatments is the shortage of participants in Alzheimer's clinical trials. If you want to add a dose of activism to your mixture of hope and realism, check out the Alzheimer's Association's TrialMatch program and find out whether there's a clinical trial near you.
About Guest Blog Author Carrie Steckl, Ph.D.
Carrie Steckl, Ph.D. is a freelance writer specializing in caregiving, psychology, and aging. Her blog, "Ask Dr. Chill," provides practical answers to the toughest caregiving questions.


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Re-engineering Cultures for True Sustainability
What is true sustainability? How do we measure it and what steps need to be taken to get there? If true sustainability cannot be achieved how do we best prepare for the coming ecological decline?
Come hear from Erik Assadourian about how leading thinkers are answering these questions. Erik is a Senior Fellow and co-director of Worldwatch's State of the World 2013: Is Sustainability Still Possible?, a compilation of writings on preparing our culture and economy for potentially turbulent times. The evening will consist of a talk by Erik and a chance to discuss these issues with fellow students, faculty, and community members.
There will be a book signing and reception following the presentation. Then from 6:00 - 7:30 pm, come learn to play the climate change version of the popular board game "The Settlers of Catan!" "Catan: Oil Springs" is a scenario written by Erik Assadourian and Ty Hansen. It was developed by Worldwatch's Transforming Cultures Project for the purpose of creating awareness about the effects of the usage of oil on the environment. Erik will bring several sets of the game for multiple players.
This event is co-sponsored by the IL Sustainable Technology Center (a division of the Prairie Research Institute) and the Center for a Sustainable Environment at U of IL.
Both activities are free and open to University of Illinois faculty, staff, and students as well as the general public. Click here for more information and here to register.


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Light-emitting diodes transformationalIt seems like only yesterday when I hitchhiked from Texas A&M University to Dallas in March 1966 to meet Ed Bonin at Texas Instruments. Bonin showed me a cylinder no larger than his thumb. When he pressed a button at one end of the device, red light emerged from a tiny crystal installed in the opposite end.
This was a magical moment. It was amazing to see light emitted by a crystal the size of a grain of salt powered by a small flashlight battery.
The crystal in Bonin's miniature light source was a light-emitting diode, or LED, a device that emits light when electricity passes from one region of the crystal to another.
In 1961 Texas Instruments developed powerful LEDs that emitted invisible near-infrared light just beyond the red that we can see. These LEDs eventually evolved into the infrared light sources used in TV remote controllers, intruder alarms and military night-vision devices.
Meanwhile, Nick Holonyak Jr. had a clever idea. Holonyak worked for General Electric, the company cofounded by Thomas Edison in 1892. Edison developed the first commercially successful incandescent electric light, and in 1962 Holonyak followed in Edison's footsteps by developing the first practical LED that emitted visible light.
In 1963 Holonyak became a professor at the University of Illinois, where he trained students who went on to develop improved LEDs and lasers.
Holonyak's pioneering LED work led to the development of many kinds of red, orange, yellow and green LED indicators and readouts that displayed numbers and letters.
The blue LED completed the spectrum and permitted the development of giant display screens and advertising signs.
The white LED arrived when blue LEDs were coated with a phosphor that glows green and red when illuminated by blue light. Mixing these colors produces white light.
Today LEDs are everywhere. The monitor of the computer into which this column was typed is illuminated by LEDs. Many traffic signals and car tail lights use bright LEDs. Flashlights that employ white LEDs are much brighter than incandescent flashlights and use much less power. You can now buy long-lasting LED lamps for household use.
Holonyak received the National Medal of Science, the National Medal of Technology and various other awards for his innovative developments of LEDs and lasers. More information about the program is available on the web site at www.hmhid.com.


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Code Compliance Technical Meeting
The U.S. Department of Energy (DOE) is coordinating strategies and activities with companies, individuals, and government entities to demonstrate, quantify, and monetize energy code compliance and coordinate deployment at the local, state, and regional levels.
Energy efficiency measures in the buildings sector, if properly realized and captured, provide a tremendous opportunity to reduce energy consumption and expenditures. Yet currently there is a lack of assurance that buildings as designed realize the levels of energy efficiency established in the ratified codes. As such, building owners and occupants may in turn not be realizing the energy and cost savings benefits inherent in the code. A year-long study by NYSERDA, Improved Code Enforcement: A Powerful Policy Tool- Lessons Learned from New York State, on the evaluation of energy code compliance in New York estimates cost impacts of $373 per year for each non-compliant home. Lost energy code savings for the commercial sector were estimated at 5% of annual energy costs, or about $0.10 per square foot of floor area. Lost benefits is one of the great shortcoming in ensuring buildings are a proactive, reliable energy resource now and into the future.
Through combined efforts, consumers now have the opportunity to achieve cost-effective energy savings from advances in the model codes and standards that are 30% more efficient than just 7 or 8 years ago. To realize these opportunities, priorities may shift to reflect improved compliance in order to insure that consumers and structures are realizing these large efficiency gains — and to ensure both the consumer and building are achieving the savings (i.e. that the savings are real, tangible, and bankable). Furthermore, effective compliance and enforcement may unlock deeper energy savings, reduced consumer costs, higher building resale value, and minimized environmental impact.
Presentation Materials
As a first step to better understanding a range of perspectives on energy code compliance, the DOE Building Energy Codes Program held a technical meeting in April 2013 in Washington, DC. Download and view the program from the meeting. Presentations on recent efforts nationwide included:
- Findings from Report on Involvement of Utilities in Code Adoption and Implementation; Harry Misuriello, ACEEE
- Attribution for Energy Savings Report; Carolyn Sarno, NEEP
- Impact of Requiring HERS Ratings and the Benefits of Performance-based Codes; Ian Finlayson, Massachusetts Department of Energy Resources
- Compliance Efforts in Minnesota; Bruce Nelson, Minnesota Department of Commerce
- Compliance Efforts in the Northwest; Gary Nordeen, Washington State University
- Expanding the Conversation to Conquer Compliance; Eric Makela, BrittMakela Group
- Energy Code Ambassadors Project and Recent Consumer Outreach Efforts; Maureen Guttman, BCAP
- Utility Savings Estimator Tool; Sean McDonald, PNNL
Additional Resources
In addition to the presentations and takeaways from the Compliance Technical Meeting, the following reports referenced in many of the presentations above provide insights from case studies and lessons learned which will inform the development of compliance models.
- Building Energy Code Advancement through Utility Support and Engagement; ACEEE
- Attributing Building Energy Code Savings to Energy Efficiency Programs; NEEP, IMT, & IEE
- Washington Residential Energy Code Compliance Study; The Cadmus Group
- Integrating Codes and Standards into Electric Utility Energy Efficiency Portfolios; IEE
- Leveraging State Energy Office-Utility Partnerships to Advance Building Energy Codes; NASEO


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EB(4) NetBSD Kernel Interfaces Manual EB(4) NAME eb -- ANT ``EtherB'' Ethernet driver SYNOPSIS eb* at podulebus0 slot ? DESCRIPTION The eb driver provides access to a 10 Mb/s Ethernet network through a card based on the SEEQ 80C04 Ethernet Data Link Controller. The cards supported by this driver are generally those supported by the ``EtherB'' driver under RISC OS. These include: · ANT EtherB network slot card · Acorn AEH61 SEE ALSO ea(4), netintro(4), podulebus(4), ifconfig(8) NetBSD 7.0 April 6, 2001 NetBSD 7.0
You can also request any man page by name and (optionally) by section:


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FAQs / Common Issues
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- I can't find the offer price camelcamelcamel is reporting.
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- Why do I not see all price types?
- What is repricing?
- What about shipping & handling prices?
Contacting Us
If the FAQs don't help, please visit the contact information page and use your preferred method to get in touch with us. We will do our best to resolve your problem.
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Ravens inside linebacker Jameel McClain has had a busy week preparing for a Philadelphia Eagles offense led by quarterback Michael Vick and running back LeSean McCoy. On top of that, McClain will also be getting ready to play a regular-season NFL game in his hometown of Philadelphia for the first time in his career. Here are some of his thoughts heading into the game.
How many family and friends do you expect to be at Lincoln Financial Field?
I'm going to tell you what's the crazy thing. It might be a sign because literally, I lost my phone three days ago. So I have only four or five people coming. I think it was supposed to be like 16 or 18. So it got me out of trouble with the ticket requests. I literally got like four people coming now. … For me, just the opportunity to play in itself, I'm excited about. But when you have the chance to go home and play in front of people who rooted for you throughout your career, it makes it a little more special.
How dangerous is the Eagles' offense?
They're dangerous. They're definitely fast. They are all pretty fast. I work out with LeSean [McCoy] when I'm in Philly, so I know the type of ability that he has and all the moves that he can make. It definitely creates a challenge for the defense, but playing physical, downhill ball, when you hit people in the mouth, everything slows down for people at that point.
Do you sort of disregard Michael Vick's poor performance from last week?
Absolutely. You don't judge someone's track record off of one game. Michael Vick has been a productive player in this league for a long time. We would be fools to judge him off of one game.


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Berchtesgaden and the Caché at Eagle's Nest
"Wine and War: The French, The Nazis & The Battle for France's Greatest Treasure" by Don and Petie Kladstrup is a remarkable book that illuminates the untold stories surrounding the wine community in France during WWII under the Nazi occupation.
In short, the German government restricted the sale of French wine to anywhere in the world, save for Germany. The economic impact this had on winemakers was devastating. Hitler wanted for himself all of France's wine treasures and even appointed weinführers to oversee all of Bordeaux's production (as well as other wine producing regions) just to ensure that the Third Reich would be well stocked with the best wines France had to offer. Enter: Eagle's Nest.
The book focuses on Berchtesgaden (berkh-tuh s-gahd-n), a town in the German Bavarian Alps where Hitler lived, and where members of the Third Reich vacationed. Absolutely picturesque in every way, its beauty is contrasted by the ugly German inhabitants with which it is associated. The Kehlsteinhaus (a.k.a. Eagle's Nest), was a chalet-style building built by the Nazis in the mountains near Berchtesgaden as an official 50th birthday present for Adolf Hitler. It was here, on May 4, 1945, that the French 5th Tactical Group along with the American 21st Army Corps discovered a caché of France's greatest wine treasures. The French arrived on the scene first, and a twenty-three-year-old army sergeant from Champagne, was sent up the mountain to Eagle's Nest some 6,017 feet above sea level. He was the first person to set eyes on the half million bottles of French wine, from the likes of Château Lafite-Rothschild, Mouton Rothschild, Latour, d'Yquem, Romanée-Conti, bottles of champagne including, Krug, Moët, Piper-Heidsieck, and Pommery, on and on.
During the war French Winemakers did what they could to keep as much of their prized wines hidden from the Nazis. They re-labeled plonk wines as the best wines, and poured their finest elixirs into plonk bottles. If ever there is confusion in counterfeit wines between the years of 1939 and 1945, it is a noble confusion, for much of what the Germans received was doctored "plonk." These tactics did not always work, however, and many people lost their lives or were imprisoned for their efforts—the Germans certainly drank their fill of magnificent wines.
The other side of this story tells how the Resistance found shelter in the wine caves and cellars throughout France, and it was in these darkened places that the men, women, and children of France bravely stood up to the German occupation with determination and diligence even in the wake of utter collapse and ruin. If you have in your cellar any French wines from this era – especially 1945 – be sure to drink that wine with the advice in mind from Jean Hugel, a winemaker who resisted the occupation with all his might, who said, "These wines should only be tasted under the following circumstances: on their own, outside the context of a meal, with your best wine-loving friends, in a respectful atmosphere and without the slightest reference to their price. In such a way, you will do homage to the skill and honesty of the winegrower, and equally to Nature, without whom the production of such jewels would be impossible."
"Wine and War" is available at all major book outlets and online.


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Yes that is correct all parties agree (both democrat and republican), say dont stop drilling for oil off their coast. Yes that includes all the parishes (which are controled by democrats) most effected by the spill and BOTH senators (one republican and one democrat). All agree, DONT STOP THE DRILLING OFF THEIR SHORE. Yes most agree the problem is that the safe guards needed to be there and if those failed then reaction times to clean up need to be way faster and that the federal government failed them on both.
Yes that is correct it was a man (Ken Salazar) Obama appointed to Interior Secretary that appointed the person (lizabeth Birnbaum, director of the Minerals Management Service) that not only let BP go on these safeguards. They did not miss them mind you, they actually saw them and gave them a wavier on them, but then it doesn't stop there they then also gave them a safty award, ALL ON THIS SPECIFIC RIG "DEEPWATER HORIZON".
Now lets forget that fact and that Obama appointed the people to make sure this spill does not happen in the first place. Lets move onto who did nothing and even stopped the clean up from going forward as fast as it should have. Opps that is the same people, the Obama administration, They stopped the burn off, they stopped the chemical dilutions, they even stopped the sand berms the governor wanted to place to stop the oil from coming so close to the mainland. They not only did not help in this clean up effort, THEY HINDERD IT.