INDEBT · Measuring and explaining the global debt of biotic homogenization in a changing world.

Measuring and explaining the global debt of biotic homogenization in a changing world.

This project adresses the pressing issue of biotic homogenization (BH), a critical, yet under-researched aspect of the biodiversity crisis characterized by an increase in similarity between ecological communities across regions. This trend toward homogenization, largely driven by human activities such as habitat destruction, climate change, pollution, and species introductions, reduces the turnover of species composition between locations (β-diversity). Such changes threaten ecosystems' functionality, resilience, and capacity to provide essential services. While biodiversity loss has gained substantial attention globally, BH, as a consequence of ecological simplification, has remained insufficiently understood, particularly in terms of its spatial and temporal dynamics and the multi-scale effects of global change drivers. This project addresses the urgent need to understand BH in a more comprehensive and integrative way, with the primary objective of creating a global, multi-taxa, and scale-dependent assessment of BH and identifying how its occurrence and intensity depend on specific global change drivers. This first objective aims to fill the significant knowledge gap regarding how BH is influenced by various factors such as climate change, land-use change, human population density, , each of which may act differently across spatial scales. By leveraging the BioTIME database, which compiles long-term biodiversity time-series data across various taxa and geographic locations, the project will analyze how β-diversity responds to these drivers over time and space. This large-scale, data-driven approach will provide unique insights into the spatially explicit patterns of BH, facilitating a more precise understanding of how and where specific global drivers contribute to the loss of ecological uniqueness among communities. Ultimately, this will help pinpoint the geographic and environmental contexts where conservation measures can be most effectively applied to mitigate further homogenization. The second major objective is to introduce and quantify the concept of "homogenization debt," a novel framework analogous to the well-established extinction debt in biodiversity studies. Homogenization debt refers to the time-delayed impact of past environmental changes that are likely to result in increased community similarity in the future, even if current pressures are alleviated. By exploring this lag effect, the project will map out areas most vulnerable to future homogenization, enabling a forward-looking perspective on biodiversity loss. This assessment of homogenization debt will provide an empirical basis to guide policy decisions in prioritizing conservation efforts, especially in regions where delayed homogenization might otherwise go undetected.

Data: CORDIS, © European Union