Abstract:
Biological diversity is a critical component controlling ecosystem function and resiliency, yet it remains difficult to measure at the spatial and temporal scales relevant to conservation. Recently, biodiversity surrogates have emerged as a potentially useful tool for estimating the ability of a habitat patch to support biological diversity over the long-term, termed biodiversity support potential. The objective of the present study was to assess the biodiversity support potential of forest habitat patches in North Carolina. I used the diversity of unique land cover types and biophysical conditions as surrogates for biodiversity. Biophysical conditions were captured through the use of terrain-based indices: a topographic convergence index, potential radiation load, and elevation; these were indexed and combined to generate unique environmental conditions affecting the distribution of plant community types. Modeled estimates of soil moisture were ground-truthed to verify that topographic convergence is a reasonable index of soil moisture. Natural Heritage Element Occurrences were used to weight discrete environmental conditions and land covers according to their current biodiversity value. Finally, Significant Natural Heritage Areas were used as a reference to assesses whether biodiversity surrogates effectively capture habitats presumed to have the highest biodiversity value, and thus, whether surrogates are capable of evaluating existing networks of protected lands and identifying conservation priorities. The study revealed that both environmental settings and vegetation community types may be effectively used as surrogates for biodiversity. While surrogate assessment suggests that current biodiversity value (estimated by weighted metrics) should be considered distinct from biodiversity support potential (estimated by unweighted zip code diversity), both metrics are relevant and should be incorporated into conservation planning initiatives. Using geospatial tools developed in this study, estimates of biodiversity support potential and value can be generated for all regions of the United States using existing, publicly available data. Environmental settings may be adjusted to capture the most relevant characteristics of each ecoregion, especially as additional data sets (including fine-scale soils data) becomes nationally available. Biodiversity surrogates may also be readily calibrated through the use Natural Heritage data. Thus, I call for increased cooperation and data-sharing in future conservation planning and implementation efforts.
