Pattern-process linkages in landscape ecology

Coordinator

Prof. Graeme Cumming

Overview

The earth is currently entering an age that has been termed the anthropocene, a period when human influences dominate natural processes. Most individual anthropogenic impacts occur at relatively small scales, but the combined effects of many people making small-scale changes to ecosystems can cause large-scale change. Humans and other organisms respond to landscape change across a range of scales. The central theme of this research program is to unite fine-scale and broad-scale perspectives in landscape ecology through exploring the connections between landscape pattern and landscape process at multiple scales. We are also interested in the resilience of linked social-ecological systems and the ways in which management and landscape-level changes in ecosystems interact to determine social-ecological resilience to such things as climate change, disease outbreaks, and species loss.

This programme area is one in which both theoretical and practical development are of prime importance. General theoretical synthesis and modelling, linked to detailed empirical research into specific cases, should provide insights of broader relevance. Focal areas in this program currently include (1) the role of nutrient hotspots in the landscape, and their contribution to community composition and resilience; (2) the spatial relationships between functional and taxonomic diversity; and (3) the influence of connectivity and other spatially-explicit variables on the resilience of linked social-ecological systems. All of this research will feed into attempts to develop more effective, better-informed approaches to ecosystem management and biodiversity conservation.

Nutrient hotspots as drivers of community composition

This project focuses on understanding the ecological role of large termitaria in Chizarira National Park and the area around Lake Chivero in Zimbabwe. Our initial results indicate that termitaria are acting as reservoirs of biodiversity in elephant-impacted Chizarira, helping to keep cavity-nesting birds in the system through the provision of deadwood.

Spatial patterns in functional diversity

The results of this imitative have indicated that taxonomic richness is not always a good surrogate for functional richness in South African bird communities; and that protected areas in South Africa are essential for the persistence of raptor and scavenger bird species. These analyses are now published (see my list of publications for details). We plan to pursue this theme further by exploring the impact of agricultural transformation on functional traits in the avian community.

Connectivity and resilience in social-ecological systems

This project is currently being supported by an NSF grant that was awarded to Steve Perz, Grenville Barnes, Graeme Cumming, and Jane Southworth. We are exploring the influence of the (currently under construction) trans-Amazon highway on the MAP (Madre de Dios, Accre, and Pando) area of the Amazon basin, where Bolivia, Brazil, and Peru meet. MAP is an intriguing case study because it includes three areas with similar biophysical templates and vastly different institutions and political ecologies. We have predicted that resilience of Amazonian social-ecological systems will be highest when their physical connectivity is intermediate, because the system receives new inputs from outside but is not overwhelmed by them. As connectivity changes with the construction of the Trans-Amazon highway, we are tracking changes in social systems, household economies, and plant communities. These data will be integrated with time series of land cover change, initially using space for time substitutions, to test whether system resilience changes as connectivity changes. A conceptual framework for the project was published in Ecosystems in 2005 (Cumming et al., 2005).