Marburg, A. E. 2004. Natural and anthropogenic variation in coarse woody habitat among and within lakes. MS Thesis, University of Wisconsin, Madison.

Residential development is increasing in many rural landscapes throughout the US and is often concentrated near aquatic ecosystems. Therefore, understanding terrestrial-aquatic interactions may be critical for assessing ecological effects of development. Introduction of wood from riparian forests into the littoral zone, where it becomes habitat for aquatic organisms, is a key terrestrial-aquatic interaction that is not well understood. We examined the role of forest structure, the abiotic template and land use on the density of littoral coarse woody habitat (CWH) both among and within 45 lakes in Vilas County, Wisconsin, USA, that ranged in building density from zero to 38 houses km-1 of shoreline. At both scales studied, areas more modified by humans had both a lower mean value and less variance in density of littoral CWH. Conversely, areas with little (current) human impact were tremendously variable – some sites and lakes had abundant wood and others had virtually none. Among all lakes, littoral CWH density was explained by riparian CWH, lake shape and conductivity; among low-development lakes, lake shape and conductivity were replaced in the model by lake area and the contribution of riparian CWH to the model declined (partial R2 = 0.43, p = 0.016 versus partial R2 = 0.55, p < 0.001). Among sites within lakes, littoral CWH presence and density varied with land-use intensity and exposure to wind. Contrary to previous studies, there was no relationship between living trees and CWH density, suggesting that riparian and littoral CWH densities may be strongly influenced by past disturbance, both human and natural.