Resilience is a key underpinning principle of biodiversity strategies at all levels of government. However, the definition of resilience in most strategies and policies is still relatively ambiguous, and needs to be more clearly quantified and articulated so that the success of these strategies can be measured.
Ecological resilience is generally defined as the ability of ecosystems to resist permanent structural change and maintain ecosystem functions. The ability of ecosystems and their component species to survive (and have the potential to respond) to such changes will depend on a range of factors, including genetic fitness.
Australia’s biodiversity is well adapted to variable climate conditions and to a certain frequency of extreme events. However, the current impact from cumulative pressures (including climate extremes) is beginning to seriously challenge the natural adaptive capacity of our biodiversity. There is growing evidence that some vulnerable ecosystems are undergoing permanent structural change, signalling a clear loss of resilience in these systems. For example, the structure of temperate reef communities off Western Australia in the past 5 years has changed in response to warmer waters, and there has been large-scale contraction of banksia woodlands around Perth following hot and dry conditions, magnified by rapid land-use changes.
Such changes are not confined to biodiversity in Australia; some migratory species seen in Australia are being affected by changing conditions in other parts of their range. For example, populations of numerous species of shorebirds that migrate to Australia from Siberia and northern Alaska are decreasing, some at alarming rates (Clemens et al. 2016). Excessive reclamation of coastal wetlands in Asia is limiting the ability of such species to feed and rest on their migratory journey (Iwamura et al. 2013; Murray et al. 2014, 2015).
Governments are engaged in a suite of actions to restore and support ecosystems. These include reducing the impact of drivers and pressures, increasing land dedicated to conservation (including by identifying and managing refuges), and restoring connectivity between conservation sites, especially in degraded landscapes. Action 2 of Australia’s Biodiversity Conservation Strategy 2010–2030 (National Biodiversity Strategy Review Task Group 2009) aims to build ecosystem resilience in a changing climate by:
- protecting diversity
- maintaining and re-establishing ecosystem functions
- reducing threats to biodiversity.