The study of climate change impacts on birds has increasingly been hot topic in recent years. Abundant evidence and proof shows there have been apparent changes in avian population, life history traits, and geographic ranges in react to worldwide environmental change. This paper briefly reviews the impacts of climate change on birds specifically focusing on its distribution, production and conservation concern. There have been many short- and long-term studies in the scientific field which reveals the unknown and solid facts about the possible impacts of changing climate and its implication in biodiversity.
Introduction
Climate change has become a serious threat to nature and the species. Climate change has profound implications on bird life also. Warming temperatures, rising ocean level, shifting seasons are found to be disturbing birds and their supporting biological system. There is thus evolving new researches about how species have responded to climate changes in the past based on revaluation. Birds are sensitive indicator of climate change as they respond to climatic behaviour in different way. Therefore, several past researches have been conducted in the field of conservation biology to find out the effect of climate change in bird phenology, geographic range, reproductive parts etc. Birds are already in the declining phase due to global warming and now are the canter of attention for their conservation of habitat.
This paper reviews on the climate change impacts on distribution of birds, reproductive performance and highlight the necessity for conservation concern of birds.
Effect on distribution of birds
Climate plays an important part in determining species distributions and the dynamics of distribution changes. Climate is an important determinant of geographic range for many species. Dawson and Pearson analysed the annual average temperature in many places of northern hemisphere has increased by up to a few degrees centigrade. It is found out that 3.c changes in mean annual temperature corresponds to a shift in approximately 300-400 km in latitude or 500m in elevation. Therefore, species are expected to move upward in elevation or towards the pole in latitude in response in response to increasing temperatures. That shows climate is affecting the distribution of species.
There is many other triggering factors that affects the range expansion.
Miranda studied on the impact of climate change on Amazonian avian assemblages considering range shifts, species loss, vulnerability of ecosystem functioning, future effectiveness of current protected areas and potential climatically stable areas for conservation actions. Species distribution modelling based on two algorithms and three different scenarios of climate change was used to forecast 501 avian species, organized on main ecosystem functions (frugivores, insectivores and nectarivores) for years 2050 and 2070.
Effects on breeding population of birds
Bonnet estimate the effects of climate change on annual breeding productivity and population viability up to 2100 of a common forest songbird, the Acadian flycatcher (Empidonax virescens), across the Central Hardwoods ecoregion, a 39.5-million-hectare area of temperate and broadleaf forests in the USA and the result showed that warming temperatures under a worst-case scenario with unabated climate change could reduce breeding productivity to an extent that this currently abundant species will suffer population declines substantial enough to pose a significant risk of quasi-extinction from the region in the twenty-first century.
Bonnot test combine individual-based2 and metapopulation models to estimate the effects of climate change on annual breeding productivity and population viability up to 2100 of a common forest songbird, the Acadian flycatcher (Empidonax virescens), across the Central Hardwoods ecoregion, a 39.5-million-hectare area of temperate and broadleaf forests in the USA and found that climate warming reduced flycatcher nest success (defined as the compound probability of a nest surviving the entire 32-day period to fledge young) and annual productivity, posing a significant risk to population viability on a large spatial scale. The low end of the precipitation range brings the population near reproductive failure. Any change in climate that would increase the frequency of extreme dry conditions would likely endanger populations of these species.”
Bolger studied four species of year-round resident birds thatare wholly or largely dependent on coastal sage scrub asbreeding habitat in this region: the wrentit (Chamaeafasciata), spotted towhee (Pipilo maculatus), Californiatowhee (P. crissalis), and rufous-crowned sparrow. They search about the relationship between rainfall and food limitation on avian reproduction and the result showed that rainfall is a strong exogenous driver of avian reproduction in this semi-arid region through its effect on food resource availability. Our measures of arthro-pod abundance were significantly lower in 2001 than 2002. It is likely that the reduced arthropod abundance in 2002 was due to lower primary productivity. The relationship between rainfall variation and reproductive success suggests that any increase in the frequency of extreme dry years could significantly diminish the viability of populations of these species.
Birds conservation concern form impact of climate change
Some of the researches preferred to extend the protected areas to better preserve biodiversity in the changing climate landscapes with significant amounts of protected areas alleviate the negative effects of climate warming on biodiversity. Virkalla analysed the distributional changes of species more pronounced in unprotected than in protected areas, that is can a protected area network be resilient in relation to climate change in preserving
species of conservation concern. Their findings showed that landscapes with significant amounts of protected areas alleviate the negative effects of climate warming on biodiversity. Such negative impacts are apparently more pronounced in unprotected areas due to their lower richness of species of conservation concern.
Conservation of different types of bird species needs different types of approaches and further research in this topic needs to be done.
Conclusion
Research shows species depend on high-elevation forest habitat, long-distance migrants, and coastal breeders are most at risk from climate change. According to Newton, climate change is a long term cumulative process, and its ecological consequences are complex and multifratrol. To maintain a strategic distance from the most exceedingly awful impacts of environmental change we have to diminish ozone depleting substance emanations at all scales, from individual activities to worldwide understandings. At the same time we can also protect species from impact of climate change by reducing existing stressor of ecosystem.