The shift in forest management goals over the last several decades to meet societal demands for more non-timber benefits has led to a move towards ecosystem-based approaches to management, with biodiversity conservation being a major objective. Within this context, maintaining the richness and diversity of bird species on working forest landscapes has continued to be a priority in sustainable forest management. Ecosystems are heterogeneous in space and time, and regional species diversity is maintained by spatial patterns of heterogeneity at multiple scales. Understanding how patterns of heterogeneity in forest composition and structure influence species diversity is crucial to sustainable forest management. However, despite a great deal of research on habitat relationships of forest bird species, there is little understanding of how patterns of heterogeneity across scales influence regional bird species diversity. Therefore, my research goal was to investigate the relationship of bird species diversity to patterns of forest composition and structure across multiple spatial scales on a managed forest landscape. The first chapter investigates how patterns of heterogeneity in stand-level attributes impact patterns of bird community diversity across multiple spatial scales. Chapter 2 demonstrates a novel application of the conservation filters strategy to maintaining avian diversity on managed forests by working at 2 different operational scales. The third chapter looks at monitoring beta diversity in bird communities at multiple spatial scales as an alternative paradigm to species-level strategies for tracking changes in regional biodiversity.The research in these chapters draws several conclusions that are fundamental to the problem of maintaining regional biodiversity on managed forest landscapes. The first is that the relationship of environmental heterogeneity to bird community diversity changes across spatial scales. The second conclusion is that uncommon vegetation community types have a greater relative contribution to regional diversity, and the importance of specific compositional and structural attributes changes among types. Third, quantifying beta diversity of bird communities (differences among spatial units within a region) across multiple scales, using a hierarchical cluster sampling design, reflects environmental heterogeneity and offers an efficient and effective system for monitoring changes in regional biodiversity. The research presented in this dissertation offers an expanded and integrated view of the problem of maintaining biodiversity on managed forests. I have demonstrated that large-scale management systems must explicitly address how forest planning will impact patterns at multiple scales simultaneously, and maintain both homogenous and heterogeneous landscapes at the appropriate scales. My work offers an integrated set of guidelines for biodiversity conservation on managed forests that explicitly accounts for the multiple scales at which biodiversity is generated and maintained. I believe that this research provides ecologists, land managers, and planners with an improved framework for managing forests under the ecosystem management paradigm.
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