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The University of Arizona: Investigating the Effects of Re-introduced Beaver (Castor canadensis) on Avian Community Dynamics Along the San Pedro River, Arizona Amount awarded: $4,900 Objetivos: 1) Compare (a) density, (b) nest success, (c) species richness, and (d) diversity of bird species found in areas influenced by beaver as compared to those without beavers at multiple scales in the SPRNCA (San Pedro Riparian National Conservation Area); 2) Describe influence of beaver on vegetation and habitat structure that may explain bird community dynamics; 3) Inform land managers and restoration ecologists regarding potential influence of beaver re-introduction projects on local bird communities, especially in riparian ecosystems of the southwest. Project Description: The San Pedro River's riparian forest is a regionally important area for breeding and migrating birds. Riparian areas comprise less than 1% of the western United States, yet provide habitat for a disproportionate number of animals, including the majority of breeding bird species in the southwestern US. More than 90% of the riparian areas throughout the west have been altered or destroyed by human activities and much of what remains is severely degraded; therefore, remnant riparian patches are critically important to bird populations in the southwest. Conserving and restoring riparian environments is crucial to effective management of bird populations and other wildlife dependent on these areas. Many land managers and restoration ecologists see the re-establishment of beaver as a potentially invaluable and low-cost tool for the restoration of riparian environments. In 1999, the Bureau of Land Management, in cooperation with the Arizona Game and Fish Department, re-introduced beaver in the San Pedro Riparian National Conservation Area, resulting in their successful establishment. Because diversity and density of breeding birds increases with volume and density of vegetation, bird communities will likely be influenced by beaver. Beaver reduce vegetation cover through direct harvest of woody species, as well as increase cover by increasing the width of riparian areas, the quantity of available water, and increasing vegetation productivity. Effective management of riparian systems requires that we understand how beaver activity affects bird communities. In this study, we will quantify the influence of beaver on bird community composition on the San Pedro, and, for select priority bird species, we will determine differences in density and nest success among areas with and without beaver. Contact: |
