Professor Emeritus, University of Georgia & Luquillo LTER

Dr. Alan P. Covich is a professor of ecology and former director of the Institute of Ecology in the Odum School of Ecology at the University of Georgia, USA.  He chaired Colorado State University’s Department of Fishery and Wildlife Biology and was on the faculty of the University of Oklahoma and Washington University-St Louis. 

He received a Ph.D. in Biology from Yale University and A.B. degree from Washington University. His research focuses on impacts of droughts, floods and hurricanes on freshwater ecosystem services and food webs at river-network scale. Covich is a past-president of the International Association of Ecology, the Ecological Society of America, the American Institute of Biological Sciences, and the North American Benthological Society (now the Society for Freshwater Science).

He received the Icko Iben Award for Excellence by the American Water Resources Association, the Distinguished Service Award by the Ecological Society of America, and was elected a Fellow of the American Association for the Advancement of Science, the Ecological Society of America, and the Society for Freshwater Science.

Covich co-edited three editions of the Ecology and Classification of North American Freshwater Invertebrates, as well as reviews on climate change and drought impacts on ecosystems for Resources for the Future, and book chapters (Water in Crisis, Encyclopedia of Biodiversity, Encyclopedia of Islands, and the Encyclopedia of Hydrologic Processes). He has served on ecosystem review panels for the U.S. National Science Foundation and several international organizations.

On the impacts of multiple disturbances on the resiliency of tropical freshwater food webs and ecosystem services in the Luquillo Experimental Forest, Puerto Rico

Climate change is altering the frequency and intensity of hurricanes and droughts on Caribbean Island ecosystems. Our long-term data over more than three decades allowed us to analyze the impacts of multiple hurricanes and severe droughts on stream food webs in the El Yunque National Forest, Puerto Rico.  Common effects of both types of disturbance are a pulse of riparian leaf litter and an increase in light so that leaf-litter processing by detritivores and grazing by macroinvertebrates generally are increased. However, the hydrological effects can be distinct and variable in that very low flows can lead to deoxygenation and slow infilling of substrata. In contrast, high flows associated with hurricanes create debris dams and can rapidly increase stream bank erosion causing sedimentation of shallow pools. We have observed that the diversity of the stream fauna is resilient especially to flooding during hurricanes apparently as a result of a long evolutionary history and adaptations for these impacts. Adaptations to droughts, however, appear less effective. Movement by some macroconsumers from pools with decreased flow, lower volume, and less dissolved oxygen to higher-quality deep, well-oxygenated pools can potentially mitigate some drought effects but more analysis and modeling are needed to evaluate directionality of macroconsumer movements. Our study highlights the potential long-term effects of multiple disturbances on stream food webs and associated ecosystem processes in response to increasing extreme events resulting from Caribbean climate change. These rainforest streams provide important ecosystem services to surrounding communities that depend on stream flows for water supplies and recreation.