Estimating Watershed Biodiversity: An Empirical Study of the Chesapeake Bay in Maryland, USA

摘要

There has been increasing demand for rigorous methods for evaluating biodiversity, one of the ecosystem services that sustains and fulfills human life. After carefully examining the literature, we found three key points that should be taken into account when we evaluate biodiversity. The first point is that any u22indicator speciesu22 tends to be a leaky target of biodiversity. The second point is that u22bufferingu22 that is useful for representing the ecological concept of boundaries should have scientific meanings. The third point is that a u22watershedu22 that integrates most natural processes is advantageous as the spatial range for evaluation. Based on these considerations, we developed the Biodiversity Probability Index (BPI) to account for biodiversity. We analyzed the relationship between BPI and total economic value of ecosystem services per unit area in order to test the reliability and utility of BPI. All BPI values were under a positive regression curve. The curve showed the highest economic value that could be achieved at a given biodiversity status. Based on our findings along the analysis, we conclude that the BPI has two advantages: (1) The BPI identifies the extent of the impact on biodiversity within a given landscape, and its composition of each category of species helps to identify what kind of wild life habitat could be seriously threatened by future land use development; (2) The BPI tells not only the biodiversity condition in ecological sense, but also provides the potential total economic value of ecosystem services, which will be achieved under ideal conditions.