BEAVER LODGE DISTRIBUTIONS AND DAMAGE ASSESSMENTS IN A FORESTED WETLAND ECOSYSTEM IN THE SOUTHERN UNITED-STATES

Caddo Lake, USA, a Ramsar Wetland of International Importance, is a la custrine wetland complex consisting of stands of flooded baldcypress i ntermixed with open water and emergent wetland habitats. Recently, con cern has been expressed over a perceived increase in the beaver popula tion and the impact of beaver on the long-term sustainability of the b aldcypress ecosystem. We used intensive beaver lodge surveys to determ ine the distribution and relative abundance of beaver and the amount, type, and distribution of beaver damage to mature trees and seedlings at Caddo Lake. A total of 229 lodges were located with a combination o f aerial and boat/ground surveys. Most lodges were located in open wat er and edge habitats. About 95% of the lodges were occupied by beaver or nutria. Some form of damage was exhibited by one or more trees near 85% of the lodges. Intensive damage assessments around 35 lodges indi cated that most damage to trees, baldcypress in particular, was restri cted to peeling or stripping of bark which is believed to have minimal effect on tree survival. Surveys of regeneration indicated that baldc ypress seedlings were very abundant; however, over 99.9% were less tha n 30 cm tall. The lack of recruitment into the larger size classes app ears to be a result of high stand densities and water management pract ices. At this time, the young age and density of the baldcypress fores ts suggest that recruitment is not a major concern and herbivore damag e appears to be having a minimal effect on the forest. (C) 1998 Elsevi er Science B.V. All rights reserved.