Human-made climate change and land use change are among the major threats to terrestrial biodiversity, and understanding their impact on species and ecosystems is key to developing appropriate responses. However, these two global change drivers often interact, making it difficult to predict biodiversity change. In this thesis, I will examine interactions between climate change and land use change to improve our understanding of how these interactions alter biodiversity, ultimately increasing our ability to predict ecological consequences from multiple interacting pressures. I focus on the impacts of climate change-land use change interactions in the W-Arly-Pendjari transboundary protected area complex, a biodiverse ensemble of protected areas in West Africa.
In Chapter 1, I review existing knowledge about climate change-land use change interactions, before developing a risk-based framework that allows identifying mechanisms by which climate change alters biodiversity’s exposure, sensitivity, and capacity to adapt to land use change (and vice versa). These mechanisms can be combined to derive an overall climate change-land use change interaction risk for a given biodiversity unit. Then, in Chapter 2, I investigate two candidate mechanisms driving the interaction between changes in climate (in the form of rainfall) and land use (in the form of cropland) and its effect on fire dynamics across the W-Arly-Pendjari complex, showing that cropland dampens the effects of differences in grass production on fire size. Chapter 3 focuses on the interaction between the distribution of surface water (which depends on climate, i.e. rainfall) and use of land for growing crops, hunting, and wildlife tourism, and the effect of this interaction on the distribution of wild herbivore pressure. There is limited evidence for an interaction between surface water and human land use, but its effect on herbivore pressure intensity is overall small and varies by feeding guild...