Accounting for diversity of plant species in watershed ecosystems by integrating field study and remote sensing

Diversity of plant species in watershed ecosystems was evaluated by Biodiversity Probability Index (BPI). BPI was calculated from HSI (Habitat Suitability Index) of all plant species and land area of ecotope, which was acquired by some geo-information, including vegetation data from field survey and land cover data from the satellite images of Landsat-TM. High BPI zone are concentrated on the mountain range from northeast to southwest. In contrast, BPI tends to be low in watersheds in southern fringe of Yanbaru, and in lower watersheds on western and eastern Yanbaru, where villages are developed. Using satellite images enabled to put values on watersheds over a large area. This model will help to evaluate human or natural impact such as alterations of water flow, changes of ecotope type, and declines of plant species, on the diversity of plant species in told. Improvement for practical use in forest management at local scale will be expected by combining finer resolution of satellite images that will make land cover categories detail and by developing techniques to uncover the vertical structures of forests.