Rethinking the habitat fragmentation debate: what drives variability in biodiversity responses to habitat fragmentation?  

Laura Graham, Associate Professor and IIASA-NERC Research Fellow, School of Geography, Earth and Environmental Sciences, University of Birmingham. 

Wednesday 13th November, 1-2pm, Cottrell LT 2V1 and streamed on Teams (if the link does not work for you contact tony.robertson[a]stir.ac.uk). This seminar is open to all staff, students and affiliates of the University of Stirling. The seminar is hosted by Biological and Environmental Sciences (BES).

Who the talk might appeal to: While my talk is focused around a blend of landscape ecology and macroecology, and using these approaches to understand what drives species responses to habitat fragmentation, I believe this will have broader appeal beyond just landscape/macroecologists. The research presented is part of a broader body of research in which I bring together big data approaches and complex systems thinking to understand species responses to environmental change. Additionally, the implications of the research span beyond ecological theory. By understanding how the spatial structure of landscapes affects biodiversity, we can build this knowledge into development and management plans.

Abstract: The relationship between habitat fragmentation and biodiversity is a matter of current debate in the ecological literature. While we understand the negative influence of habitat loss on biodiversity, the effect of the spatial arrangement of remaining habitat (often termed fragmentation per se) is less well understood. We argue that the appropriate question is not “what is the effect of habitat fragmentation on biodiversity?”, but “what are the drivers of the variability in the effect of habitat fragmentation on biodiversity?”. It is crucial to understand what drives the fragmentation–biodiversity relationship both to advance ecological theory, and to inform spatial planning. For example, we could build understanding of the impacts of spatial arrangement of habitat on biodiversity into urban planning or agri-environment schemes. Using 1233 effect sizes from 200 studies, we examine the influence of ecological and methodological factors on the heterogeneity in these effect sizes. We find that ecological factors such as taxonomic group, biome and focal habitat explain very little variability in effect sizes. However, two methodological factors stand out in explaining heterogeneity in effect sizes: the choice of fragmentation metric, and the scale at which the analysis was conducted. We conclude that to move forward our understanding of the relationship between habitat fragmentation and biodiversity, we need to focus less on dichotomous arguments and gain an understanding of the nuance of the data, the mechanisms underlying the relationship, and how they act together in a complex system.

Bio: I am a computational/spatial ecologist interested in understanding how anthropogenic changes such as climate and land-use change affect global ecosystems, and how this in turn affects human well-being. I am particularly interested in using novel statistical methods and heterogeneous sources of data to answer applied and theoretical questions. I was previously a mathematician and database developer, and apply skills learned there to answer ecological questions. My current research focuses are:

• Applying complex systems thinking to understanding the drivers of the biodiversity–landscape structure approach
• Estimating ecological time-lags for their incorporation in policy
• Understanding synergies and trade-offs between management approaches for different environmental goals.