![]() |
Hilary CookeEcology of the cavity-using community in mixedwood boreal
forest
|
Ph.D. Research The functional relationships among the species creating and using cavities, and the flow of the cavity resource through the community, has been described as a nest web, a novel approach to studying communities based in food web theory (see Martin and Eadie 1999 Forest Eco & Man 115:243). In the interior coniferous forests of central B.C., Martin et al. (2004) found support for this bottom-up model of community organization, with the cavity resource flowing up from the primary excavators to a diverse group of secondary nesters. Northern Flickers were identified as a keystone excavator, creating the majority of cavities used by secondary nesters. Given differences in forest structure, and the composition of the cavity-using community, it is likely that the cavity nest web for old mixedwood boreal systems differs from that described for interior B.C. Old mixedwood boreal forest stands (>100 yrs) are characterized by
high densities of large trees, snags, and trees infected with heartrot
fungi. Consequently, there is a richer and more abundant community of
cavity Impacts of clearcut timber harvest have prompted forestry companies to
adopt a "natural disturbance model" (NDM), which attempts to
approximate fire and fire skips by harvesting larger areas and leaving
larger patches of trees and snags. Under this approach, harvest effects
may be ameliorated if retained patches act as "lifeboats", supporting
the primary excavators and secondary users, and the functional relationships
among them, found in old forest cavity communities. The relative value
of retained forest patches to act as "lifeboats" may depend
on the size, shape, and structure of retained patches. My research objectives are 1) to describe the cavity nest web for oldmixedwood boreal forest and to identify keystone excavators; 2) to determine the value of retained forest patches as "lifeboats" for maintaining functional relationships among cavity users by describing the nest web for NDM harvested landscapes and contrasting it with the nest web for intact forest landscapes; and, 3) to characterize key features of occupied cavity trees, and the local habitat and landscape structure surrounding them. Photos by C. Kolacz. Professional Background My field research experiences include studying Neotropical migrant songbirds and habitat fragmentation with the University of Guelph, and Bald Eagles and landbirds with the Point Reyes Bird Observatory (Stinson Beach, California). Before coming to the University of Alberta, I worked for five years with
the Wildlife
Conservation Society studying riparian birds in arid regions of California,
Oregon, and Wyoming. My research focused on responses of songbirds to
riparian restoration accomplished through alternative grazing My extra-curricular activities at the University of Alberta include the
Biology Graduate Student
Association Executive and cofounder of the Ecology Graduate Student
Seminar Series.
|
Last Modified:2004-11-29 |