Browsing by Author "McWethy, David Burch"

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Bird response to landscape pattern and disturbance across productivity gradients in forests of the Pacific Northwest
(Montana State University - Bozeman, College of Letters & Science, 2007) McWethy, David Burch; Chairperson, Graduate Committee: Andrew Hansen
Managing forest lands for biodiversity is a common goal in the public and private forests of the Pacific Northwest and is typically achieved through harvests that result in an array of vegetation structural conditions that provide suitable habitat for a number of species. The assumption is made that the causative factors of biodiversity do not vary geographically and that silviculture, as a management tool, can be applied similarly across different biophysical locales. The primary aim of this research is to better understand how species respond to both local and landscape-scale forest structural conditions in landscapes with different levels of productivity (e.g. gross primary productivity). We hypothesized that the influence of landscape effects on bird richness, abundance and community organization would be more pronounced in highly productive environments. We also hypothesized that species response to disturbance would differ across gradients in ecosystem productivity. We predicted that bird diversity would increase with increasing disturbance extent where favorable climatic conditions result in high levels of competitive exclusion. Alternatively, we predicted that bird diversity would decrease with increasing disturbance extent when factors other than competition limit or regulate bird species diversity.