In this post Robin Hale discusses his Review paper with Stephen Swearer ‘When good animals love bad restored habitats: how maladaptive habitat selection can constrain restoration‘
Restoration is vital to offset the effects of habitat loss on biodiversity
Recent biodiversity assessments paint a bleak picture. For example, vertebrates have suffered dramatic population declines (e.g. by 58% since 1970) and been lost at 100 times the expected background rate over the last century. One of the primary causes is habitat loss, which is the most profound threat to biodiversity in terrestrial and freshwater biomes and second in the ocean. Habitat restoration is therefore essential but often animals fail to respond. Our recent paper explores how improving our understanding of animal behaviour, in particular how animals perceive and respond to habitats, can help improve the likelihood of restoration success.
Maladaptive habitat selection can compromise restoration
Restoration is often based on our human assumptions of what constitutes suitable habitat for animals, usually in terms of structural components such as vegetation type. What happens, though, when our notions of habitat poorly reflect how animals perceive and respond to the environment? One possibility is that habitat conditions in restored sites improve, but animals fail to detect these changes and thus fail to colonise restored sites. For example, birds may avoid replanted sites where vegetation structure has improved but that lack suitable settlement cues (e.g. calling conspecifics). It is also possible that restoration inadvertently creates ‘ecological traps’ – habitats that are preferred by animals but where their fitness is reduced. For example, butterflies that oviposited more frequently in restored wetlands in southern Oregon suffered significantly reduced survival when these sites flooded. We consider how ecological traps can arise in the context of ecological restoration, using several case studies from a range of different systems and types of restoration. We also outline when we predict restoration is most likely to cause traps, and when animals will be most affected.
What can applied ecologists and restoration practitioners do?
Our paper highlights that tight links between habitat quality and habitat selection are vital to help ensure restoration succeeds. The crux is how ‘habitat’ is defined. We highlight that taking an animal-centric view of the environment is critical, especially in terms of how biota perceive and respond to the environment. One useful method to do so is the ‘resource-based habitat approach’ which incorporates knowledge of the requirements of animals at different life-cycle stages and how these requirements affect their behaviour. Developed initially with butterflies, this approach could be more widely applied to better understand the habitat requirements of different animals. We also suggest that principles from cognition (which describes the ways animals acquire, process store and act on information from the environment) could help guide restoration projects. Recently it has been proposed that cognition can be used to mitigate problematic animal behaviours, and we illustrate how a similar approach can be applied to restoration projects.
Improving our understanding of how animals perceive and respond to habitats is important to help better guide restoration efforts in the future. We hope that our paper will help in this regard, by stimulating more discussions between restoration practitioners and evolutionary and behavioural ecologists.