Evaluating the conceptual tools for forest biodiversity conservation and their implementation in the U.S.

While much has been written describing biodiversity, its global decline, and the need for action, the scientific underpinnings guiding conservation practice have received little attention. We surveyed 10 large-scale forest management plans in the U.S. to establish which ecological concepts are commonly used to guide forest biodiversity conservation and evaluate the relative importance of these concepts in processes related to forest stewardship. We then reviewed the scientific literature to assess the degree to which these concepts are founded in antecedent ecological theory, the extent to which they have been tested, and the limits of those tests. We found that the concepts of filters (fine, meso, and coarse), reserves, matrix management, hotspots, emulating natural disturbances, diversity begets diversity, patchworks, networks, and gradients are extensively employed in the forest planning efforts we surveyed. While most of these concepts received high utility scores, coarse filter was most commonly used, closely followed by matrix management and fine filter. A survey of the literature review suggests that all concepts have both direct and indirect relationships with foundational ecological theories, such as niches, natural selection, and island biogeography. All concepts also have some empirical support based on field tests and most have received some testing in an experimental framework. Yet, experimental tests of the concepts are far from comprehensive as, among other reasons: (1) many species are yet unknown, (2) many species are difficult to measure, (3) the occurrence of taxa that are often measured do not correspond well with the occurrence of those less frequently measured, and (4) although site conditions may be replicated, the historical and landscape contexts of each test are unique. Although we document wide use of these concepts, significant constraints hinder further incorporation into forest stewardship. Predominant among these is a lack of empirical support at the spatial and temporal scales over which forest management is implemented. Practical ways to advance conservation concepts include implementing effective, efficient monitoring protocols and establishing experimental tests in an operational context. Constructive bridges must be built between science and practitioner communities to realize these goals.