Based on Discriminant Analysis to Investigate Habitat Characteristics of Uca formosensis in Hsiang-Shan Wetland

Abstract

Uca formosensis is an endemic fiddler crab in Taiwan. Hsiang-Shan Wetland is one of the few habitats left for Uca formosensis. Construction of wastewater treatment station in the wetland between Sanhsingkung river and Dachuang river may deteriorate habitats for Uca formosensis in that area. Soil sampling were taken with 100 meter intervals by grid, and particle size distribution, electrical conductivity and pH of saturated soil water, oxidation-reduction potential, heavy metal concentration, total organic content, total nitrogen, bulk density, porosity, in-situ bulk density and water content were measured in the laboratory. Soil penetration were measured in situ. Percentage of vegetation coverage were measured by aerial photograph. Average submerged time were measured by in-situ investigation and tidal records. Four types of habitats were classified by discriminant analysis. We found Uca formosensis live in the upper intertidal zone with a mean submerged time of 5.1%. Vegetation coverage percentage on the ground is less than 1.4%. Soil contains 40.4% of clay and 15.8% of sand. Penetration force is 41.6N/cm2. Discriminant analysis shows that there are 10.9 ha., 2.9 ha., 18.1 ha., 8.2 ha. classified for bare area, herbaceous plant area, mangrove area and Uca formosensis habitat, respectively.