Photo of James Karr

James R. Karr

ecology and public policy, watershed management, tropical forest ecology, conservation biology


This professor is no longer available as a faculty advisor for graduate students.

My major areas of research span the range from tropical forest ecology to aquatic ecology and watershed management to environmental policy. I am particularly interested in fostering use of ecological knowledge to resolve complex natural resource and environmental disputes. My research in recent years has concentrated on the ecology of fish and invertebrates in streams, on plants and invertebrates in shrub steppe, and the demography of tropical forest birds. I evaluate the influence of human-induced disturbances on biological systems using the index of biotic integrity (IBI) as a biologically based approach to evaluate the condition of living systems, especially water resource systems.

My research on forest birds has emphasized subjects such as habitat selection, niche partitioning, and demography. Recent work on avian demography has shown that, in contrast to long-held assumptions, differences in survival rates between tropical and temperate birds are not as extreme as once thought. Furthermore, demographic and other data for tropical birds prove valuable in interpreting information on extinction probability in small isolated populations of those species. Studies of avian extinction on Barro Colorado Island (BCI), Panama, provide insight into the number, identity, and attributes of species susceptible to local extinction. Extinction is not random at the species or guild level. Obvious patterns include disproportionate losses of large and specialized species and of species from undergrowth and foothill forest. In addition to these factors, demographic attributes (fecundity, rates of adult survival and recruitment, and population variability) interact in complex ways to vary the risk of extinction among species. Life histories that balance susceptibility to nest predation with the ability to replace clutches are essential for persistence on BCI.

Additional areas of research and writing include development and evaluation of indicators that improve our understanding of the effects of diverse human actions on the health of human and non-human living systems, on the role of scientists in influencing public policy decisions, and the ethical and moral duties of humans to other species on Earth.

Select Publications

Karr, J. R. 2002. What from ecology is relevant to design and planning? Pages 133-172 in B. R. Johnson and K. Hill, editors. Ecology and Design: Frameworks for Learning. Island Press, Washington, DC.

Karr, J. R. 2002. Understanding the consequences of human actions: Indicators from GNP to IBI. Pages 98-110 in P. Miller and L. Westra, editors. Just Ecological Integrity: The Ethics of Maintaining Planetary Life. Rowman and Littlefield, Lanham, Maryland.

Karr, J. R., J. J. Rhodes, G. W. Minshall, F. R. Hauer, R. L. Beschta, C. A. Frissell, and D. A. Perry. 2004. The effects of postfire salvage logging on aquatic ecosystems in the American West. BioScience 54:1029-1033.

Karr, J. R. 2006. Seven foundations of biological monitoring and assessment. Biologia Ambientale 20(2): 7-18. 

Karr, J. R. 2008. Ecological health indicators. Pages 1037–1041 In S. E. Jørgensen and B. D. Fath (Editor-in-Chief). Ecological Indicators. Vol. 2 of Encyclopedia of Ecology. Elsevier, Oxford. 

Karr, J. R. 2008. Attaining a sustainable society. Pages 21-37 in L. Westra, K. Bosselmann, and R. Westra, editors. Reconciling Human Existence with Ecological Integrity. Earthscan, London, UK.