There are multiple reasons that make many Australian birds vulnerable to climate change, including low genetic variation, reliance on specific disturbance or moisture regimes, and biogeographic factors such as proximity to sea-level rise or natural barrier to dispersal.
To effectively enable on the ground conservation, a knowledge of what makes a species vulnerable to climate change is important. A large majority of research defines those most vulnerable through predicted changes in range size (Huntley et al. 2008, Hole et al. 2009, Barbet-Massin et al. 2009, Doswald et al. 2009, Huntley et al. 2012, Bagchi et al. 2013, Langham et al. 2015). Biological characteristics of a species may however be important in recognising how vulnerable a species is to climate change (Foden et al. 2013, Lee et al. 2015). Using threatened bird species found across Australia, characteristics influencing their climate change vulnerability, and the spatial variation in vulnerability, was determined (Lee et al. 2015).
Each of the 44 bird species included was assigned a vulnerability value based on its sensitivity and both direct and indirect exposure to climate change. The sensitivity of a species was based on its biological traits; its ability to disperse, or its reliance on specific environmental conditions. The direct exposure of a species to climate change was based on the difference in temperature or moisture content influencing a species range, and its indirect exposure was based on a species distribution in relation to sea level rise risks and anthropogenic or natural barriers.
The distribution of each species was mapped separately per sensitivity factor to look at spatial patterns in vulnerability. The most common vulnerability factor was low genetic variation, followed by reliance on a specific disturbance or moisture regime. With low genetic variation comes the reduced likelihood of individuals having the traits needed to survive. Low genetic variation is common in species already classed as threatened (Willoughby et al. 2015), due to vastly reduced population sizes caused by a range of threats.
Dependence on certain disturbance regimes, such as periodic fire, was found to increase species vulnerability to climate change, and fire frequency is predicted to have significantly increased in Australia by the end of the century (Liu et al. 2010). Fire shapes landscapes through its influence on vegetation and subsequent food supply or nesting habitat, with large impacts on patterns of avian species richness. A study across the north of Australia for example found two thirds of 44 species had range contractions in response to increased fire frequency (Reside et al. 2012).
This study highlights that different species may require different management actions, depending on which vulnerability factor is most relevant. Actions to enable population recovery and connect currently fragmented populations will bolster genetic variation, whilst specific management approaches ensuring constant water supply or specific disturbance regimes will aid other species.
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Compiled: 2015 Copyright: 2015
BirdLife International (2015) Multiple factors make Australian species vulnerable to climate change. Downloaded from http://www.birdlife.org on 12/08/2022