What We Do

Work in our group can be placed within three foci:

Please click on the descriptions below:

Fully “intact” or “naturally functioning” communities survive in disturbingly few areas on the globe. In most places, complex and dynamic forces such as competition, predation, parasitism and mutualism have been distorted by human actions and associated declines or increases of individual species. That even the sagest ecologists are seldom able to predict the outcome of perturbations to natural communities highlights both the daunting complexity of ecosystems and the need to understand more about the basic functioning and resilience of animal interactions. To the theoretical ecologist, the widespread, unanticipated trophic cascades and other non-linear community responses to species decline provide unparalleled opportunities to tease apart complex ecological relationships. However, to the conservation biologist, these “knock-on effects” or “aftershocks” of extinction are cause for alarm and suggest communities are easily pushed over thresholds beyond which irreversible “ecosystem meltdown” is one result.

In our research, we aim to quantify the impact of harvest and habitat loss on vertebrate populations and to characterize the reverberating effects of population change on community dynamics and ecosystem function. My lab’s work on these issues takes place in the Sierras and Central Valley of California, in Ghana, on Vancouver Island in British Columbia, in Tanzania, and, recently, in Etosha, Namibia. Our research at these sites investigates:

• Cascading impacts of carnivore extinctions and baboon outbreaks on ungulate and avian communities (Ghana Wildlife Division)
• Dynamics of the giant kangaroo rat, its predators and exotic plants in an altered grassland ecosystem (L. Prugh, J. Bartolome, B. Allen-Diaz, T. Bean, TNC, BLM)
• Genetic and landscape correlates of mammal range shifts (E. Rubidge, MVZ-Grinnell Resurvey Group)
• Population and community ecology of large carnivores subject to harvest (C. Burton, Ghana Wildlife Division)
• Causes of decline and impaired recovery of the Vancouver Island marmot (Environment Canada, E. Rubidge, A.R.E. Sinclair)
• Population regulation of herbivores with and without top predators (A.R.E. Sinclair, Ghana Wildlife Division)
• Non-lethal or indirect effects of hunting on ungulate survival and reproduction (C. Stoner)
• Impacts of anthrax on carnivore dynamics (S. Bellan and the Getz Lab)

Future directions

Among other future directions, I am increasingly interested in testing the assumption of density-dependence in harvested populations through studies of the indirect, or non-lethal, effects of hunting. Using pilot data I collected in Ghana, a postdoctoral researcher in my group, Chantal Stoner, and I recently submitted a proposal to examine non-lethal effects of hunting in collaboration with the Tanzania Wildlife Research Institute. Additionally, I hope to include new tools in quantifying trophic cascades in West African vertebrate communities. Specifically, I see a clear role for stable isotope analyses to better illuminate trophic shifts of populations or individual animals following top-down perturbations. I also hope to extend this area of study to additional trophic levels to consider how local extinctions of dominant or keystone mammals may cascade over decades to impact invertebrate communities, vegetation and soils.

Collaborators

W. Getz (UCB-ESPM), J. Bartolome (UCB-ESPM), B. Allen-Diaz (UCB-ESPM), A.R.E Sinclair (UBC-Zoology), A. Balmford (Cambridge U.- Zoology), MVZ-Grinnell Resurvey Team, Environment Canada, BLM, Cal. Dept. of Fish and Game, The Nature Conservancy, Wildlife Conservation Society.

The harvest of wildlife for human consumption increasingly is perceived as the primary threat to wildlife persistence in Africa, Asia and much of South America. Nevertheless, surprisingly little is known about the socio-economic and other factors that drive people to hunt in these regions, and even less is known about the short and long-term impacts of hunting on wildlife populations and communities. Research in my group attempts to fill some of the many gaps in our understanding of hunting's causes and consequences with field and community-based studies in Ghana, Tanzania, Madagascar and Cameroon. Specifically, our work examines:

• Links between human livelihoods, food supply and consumption of terrestrial and aquatic wildlife (S. Vatland, K. Weinbaum, C. Golden)
• Spatial dynamics and sustainability of hunting (K. Weinbaum, S. Sawyer, C. Golden)
• Correlates of long-term wildlife declines using time-series data from six reserves in Ghana for the period 1969-2007 (Ghana Wildlife Division)
• Dynamics of African bushmeat black-markets in North America and Europe

Future directions

With PhD students, postdocs, and four associated faculty (Getz, Fortmann, Kremen, Zilberman) interested in wildlife utilization issues, ESPM and Berkeley are on their way towards becoming a recognized center for "bushmeat" research. As our group grows, I hope to initiate broader-scale evaluations of hunting dynamics, sustainability and socio-economics across sub-Saharan Africa. To support this work, we plan to submit a proposal to NSF as part of its 2008 Biocomplexity program.

Collaborators

L. Fortmann (UCB-ESPM), W. Getz (UCB-ESPM), C. Kremen (UCB-ESPM), UBC-MVZ, Wildlife Conservation Society, Zoological Society of London, Conservation International, TRAFFIC, Bushmeat Crisis Task Force, Ghana Wildlife Division, Tanzania Wildlife Research Institute, U.S. Fish and Wildlife, USDA-APHIS.

Land planning for wildlife conservation existed long before it was advocated by Aldo Leopold in the 1930’s, but the very recent development of tools for visualizing, quantifying and modeling landscapes and animal distributions has revolutionized this field. Nowhere is this revolution clearer than in protected area planning and studies of wildlife connectivity, which have become thriving disciplines of their own thanks to inferences made possible by GIS, GPS and remote sensing. Practitioners in these fields quantify wildlife-habitat interactions and, in so doing, illuminate past, present and future patterns of wildlife occurrence and movement across vast, changing landscapes. This relatively new area of research also allows spatially-explicit planning for wildlife monitoring and provides practical strategies for land management and habitat protection while considering “real world” trade-offs for people and economies.

Research in my group employs the tools of Landscape Ecology to characterize animal movements, design and test corridor networks among protected areas, quantify interactions between people and wildlife at local and continental scales, and work with stake-holders to design and evaluate locally-based strategies for wildlife monitoring. Our data collection takes place in Tanzania, Ghana and California, but we apply our questions to sites across the globe. Specifically, we examine:

• Animal movement among national parks in Tanzania (C. Epps, WCS)
• Sampling strategies for community-based wildlife monitoring in Tanzania, Ghana, Nicaragua, Philippines, Namibia and Bhutan (C. Burton, F. Danielsen, DANIDA)
• Connectivity of bighorn sheep populations in California (C. Epps)
• Human demography along protected area borders in Africa, South America, Central America, Europe and North America (G. Wittemyer, P. Elsen, T. Bean, C. Burton)
• Feasibility of “re-wilding” North America (O. Richmond, J. McEntee)
• Spatial dynamics of wildlife declines in West Africa (C. Burton, Ghana Wildlife Division)
• Spatial and temporal dynamics of keystone rodents in the Carrizo Plain of Central California (T. Bean, L. Prugh, TNC, BLM, CDFG)

Future directions

It is a great understatement to say the marriage of Landscape Ecology and Wildlife Ecology has a bright future. The potential for rapid innovation and new inference in such areas as wildlife movement and monitoring, and habitat assessment, restoration and planning is endless and, frankly, exciting. In the near future, I hope to improve my understanding and application of spatial tools and analysis through increased interaction with colleagues and labs in ESPM that specialize in landscape ecology. Among other projects, I hope to develop landscape-scale wildlife distribution models for our research sites in California, Ghana and Tanzania that allow us to consider the potential effects of climate variability and change on populations of mammals and their communities.

Collaborators

Danish International Development Agency (DANIDA), Tanzania Wildlife Research Institute, Ghana Wildlife Division, Wildlife Conservation Society, UCB-GIIF, The Nature Conservancy, BLM, Cal. Dept. of Fish and Game.