Focal species, community representation, and physical proxies as conservation strategies: A case study in the Amphibolite Mountains, North Carolina, U.S.A.

Conservation organizations are increasingly employing representative-based conservation strategies to overcome the limits of a species-by-species approach and to expand the focus of conservation to include overall biodiversity and ecosystem processes. To compare focal-species, community-level, and physical-proxy approaches in terms of their ability to predict vegetation communities and capture rare species, we used plot-level data from the Amphibolite Mountains of North Carolina. We identified diagnostic species via indicator-species analysis to calculate predictability and capture rates at the focal-species and community levels. We performed classification and regression-tree analysis to determine whether the biotic communities could effectively be characterized by their physical environment and to assess community predictability at this scale. At both the focal-species level and the community level, common indicator species were most reliable when the indicator species were themselves habitat specialists occurring in distinct sites. In most cases, rare-species capture was maximized with a focal-species approach, but this approach required high levels of investment. Alternatively, conservation strategies based on physical proxies were not dependent on intense field surveys, but were less effective in capturing rare species. This approach may still provide an important first cut for narrowing down the number of sites requiring intense field surveys and finer-scale analysis. Both coarse-filter approaches provided effective mechanisms for targeting and protecting large-scale ecological processes and overall biodiversity, and community-level conservation also recognized the inherent value of communities beyond their capacity as representative indicators. An effective and efficient conservation-design strategy might employ each of these three conservation targets in a multistage approach. Conservation efforts could also benefit from further research into the ecological characteristics that regulate the distribution of rare species and the implications for species capture with these different conservation approaches.

Duke Scholars

Author Dean L. Urban Environmental Sciences and Policy