Planning for future climate and land-use change in the protection of global avian and mammalian biodiversity

Abstract

Global biodiversity is deteriorating, largely due to habitat loss, but increasingly because of climate change. To stop and reverse this trend, we must anticipate how climate change is likely to affect the natural world, understand how climate impacts interact with other major pressures such as land-use, and identify conservation strategies that will safeguard biodiversity amid dramatic global change. In this thesis, I make use of recent advances in data availability and modelling techniques to contribute towards this challenge.

I use best-practice statistical models to project how the distributions of terrestrial mammals and birds will change by 2070 under different socioeconomic development scenarios. Impacts are severe under high emissions scenarios, but the worst impacts can be avoided if we limit greenhouse gas emissions in line with the Paris Agreement. I also show that the biogeographic properties of species’ distributions can be used to predict which species will be most affected. In subsequent chapters, I explore important contextual information that will influence how species respond to climate change, or influence our ability to protect them.

First, I show that without rapid emissions cuts, climate impacts on nature will be inequitably distributed between countries, and demonstrate the importance of collaboration across political borders as many species shift across them. Next, I show that the expansion of human land-use over nearly half the planet is a key constraint for species on the move, since large areas of habitat they would otherwise have been expected to colonise have been lost. When considering future land-use change projections, stark contrasts appear between future development scenarios, and if we are to stop biodiversity loss, stringent emissions reductions need to be coupled with a declining land-use footprint to help species cope. Finally, it’s not just the availability but also the connectivity of habitats that is important. I reveal where a lack of habitat connectivity between protected areas is most likely to impact range-shifting species, and where conservation efforts should be targeted to preserve and restore this connectivity.

Together, my research shows that severe biodiversity losses this century are not inevitable – but to avoid them, we will need to coordinate ambitious conservation action at broad spatial scales and tackle multiple interacting pressures at once.