O. J. Reichman

Professor of Biology
Director, National Center for Ecological Analysis and Synthesis

Dr. Reichman received his Ph.D. degree in Biology at Northern Arizona University in 1974 and completed a postdoctoral appointment at the University of Utah in 1975. In 1975 he moved to the Museum of Northern Arizona as a Research Ecologist and Assistant Director for Research. In 1981 he moved to Kansas State University and while there served as Director of the Ecology Program at NSF, as Associate Vice Provost for Research, and Director of Konza Prairie Research Natural Area. Before coming to UCSB in August, 1996, Dr. Reichman served as the Assistant Director for Research of the National Biological Service.

I have two main areas of research. One involves the analyses of the impact of herbivores on plants, particularly as mediated through the spatial pattern of animal disturbances. Herbivores have direct effects on plants by consuming them, and I and my colleagues and students have investigated the relative impacts of consuming leaves and roots, especially by subterranean pocket gophers. The destruction of relatively small amounts of root material has an impact equal to the consumption of much larger portions of the above ground plant material.

Animals also have indirect effects on plants through the physical alteration of the soil (e.g., animal trails, ant mounds). I have studied the impact of pocket gopher tunnels, which are invisible and can underlie a large portion of the landscape, and the mounds these rodents build by dumping the tailings of their diggings on the soil surface. Burrows tend to be highly uniform in their distribution, while mounds tend to be highly patchy. Both of these types of disturbances generate spatially explicit patterns of influence on the surrounding plant community. Specifically, they initiate a competition-induced wave effect seen in other communities such as spruce forests. Vegetation directly over a burrow and under a mound is consumed or dies and this releases nearby plants from competition for resources such as light, nutrients, and water. These adjacent plants grow larger and capture resources from their neighbors, which, in turn, grow more slowly. This alternating pulse of resource availability generates a wave-like response in plant biomass. This pattern is overlain on the uniform and patchy distribution on the burrows and mounds to produce a complicated pattern of influence on the vegetation.

A second area of research involves strategies of long-term food storage by animals. Many species store food when it is abundant (e.g., fall) for times when it is scarce or dangerous to gather (e.g., winter). Animals that are foraging for current needs can calculate the net worth of different food types and make decisions about what to consume. However, food that is stored can change significantly in value as it ripens or spoils, altering its value at the time it is consumed compared to when it was gathered.

Fungi are common in stored food and can have multiple effects. In some cases, fungi can actually increase the value of food, but if left growing for too long can consume the substrate (the stored food), make it inedible, or even toxic. Laboratory experiments have revealed that rodents actually prefer slightly moldy seeds to sterile, and to very moldy, seeds. Thus, it should benefit animals to manage their resource to maximize the benefits and minimize the liabilities of their stored food and cohabiting microbes. Experiments have shown that several rodent species will move freshly stored food to areas that promote beneficial mold growth, but move the food, presumably to preclude further, detrimental mold growth, to areas that inhibit mold growth.

We have developed long-term inventory strategy models to compare how differences in such parameters as spoilage rate, relative abundance, and length of the storage period affect caching behavior. Results reveal that different storage strategies should be employed depending on the specific values for the above parameters. The model generates predictions that can be tested in field and laboratory experiments.

Selected References:

Reichman, O. J., J. H. Benedix, Jr., and T. R. Seastedt. 1993. Animal generated disturbances and size hierarchies in a tallgrass plant community. Ecology 74: 1281-1285.

Reichman, O. J., and E. Roberts. 1994. Computer simulation analysis of heteromyid rodent foraging in relation to seed distributions: Implications for coexistence. Aust. J. Ecol. 42: 467-477.

Gendron, R. P., and O. J. Reichman. 1995. Food perishability and inventory management: A comparison of three caching strategies. American Naturalist 145: 948-968.

Reichman, O. J. The influence of crowding and pocket gopher disturbance on growth and reproduction of a biennial, Tragopogon dubius. Proceedings of the 14th North American Prairie Conference. (In Press)

Reichman, O. J., and H. Ronald Pullman. Ecosystem management research at the National Biological Service. Ecological Applications 6: 694-696.


O. J. Reichman
National Center for Ecological Analysis and Synthesis
735 State Street, Suite 300
Santa Barbara, CA 93101-3351
(805) 892-2504
FAX: (805) 892-2510

Dept. of Ecology, Evolution, & Marine Biology
UC Santa Barbara
Santa Barbara, CA 93106
(805) 893-7901

December 17, 1996
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