Research Experiences for Undergraduates
Program in Water Research at 
Colorado State University

Mentor Information

Name Alan P. Covich

Title Professor

Department Fishery and Wildlife Biology

Work Phone 491-2372

FAX 491-5091


Project Title Cross-Site Studies of Riparian Vegetation and Effects on Stream Benthic Food Webs.

Project Abstract We will conduct comparative studies of riparian tree distributions among streams in the Rocky Mountains of Colorado and those in the Luquillo Mountains of Puerto Rico. The main focus in on stream food webs that are dominated by species that feed on organic matter derived from riparian sources. These riparian leaf inputs result in processing of organic carbon by microbes and stream invertebrates. Differences in riparian species growing along stream banks and stream biotic communities, flow regimes, nutrient concentrations, and water temperatures all are important in regulating rates of leaf litter processing. Our focus is on stream species diversity and how the presence or absence of key species can alter rates of organic processing. We examine species-specific traits that alter "processing chains" composed of different types of species. Those species that shred microbially conditioned leaves increase the concentrations of fine, suspended organic particulates that are used by filter-feeding species. This facilitation increases retention of nutrients in headwater streams during base-flow conditions. We are also contrasting the differences between native and non-native species of riparian trees that differ in the quantities and types of leaf-litter production. Students will learn field methods for collecting plants species, measuring rates of organic matter production, instream measurements of organic size fractions, and differences among species in their uptake and processing of differently sized organic particulates. The student will spend half of their time in Colorado and half in Puerto Rico. Travel expenses for Puerto Rico will be covered by an on-going NSF grant for Long-Term Ecological Research in the Luquillo Experimental Forest. Out previous 12 years of study provide a basis for comparisons with montane, headwater streams in Colorado. We propose to have the REU participant begin work in Colorado for several weeks, then do comparable studies for 2 weeks in Puerto Rico before returning to Colorado to prepare a report and to participate in the on-campus meetings.