The Study On Elevational Patterns Of Plant, Amphibian And Reptile Species Diversity In The Baishuijiang Nature Reserve

Accurate understanding of the relationships between the species diversity along elevational gradients and their factors contributes to revealing the sustainable mechanisms and predicting the influences of global change on the diversity.However, nowadays, the patterns of species diversity and their factors have focused on the subtropic and warm temperature zone. Little evidence on those was available for transitional zone between the subtropic and warm temperature zone. Therefore, it was unclear what the patterns of species diversity along elevational gradients and their mechanisms were.Beishuijiang Nature Reserve was located in the transitional zone between subtropic and warm temperature zone, where elevational lag was large and species were extremely rich. Building earlier, together with a low intensity of human disturbance, made it an ideal region for studying elevation-species patterns and their mechanisms. In order to know about the patterns of diversity along the elevation in the transitional zone between subtropic and warm temperature zone, we chose Baishuijiang Natural Region as study region and plant, amphibian, and reptiles as studying object by checking the library record and specimen. Using these data,digital elevation model(DEM), climate, and mid-domain effect(MDE), with the help of related hypotheses ecologists have put forward to explain the biodiversity geographical distribution, and employing statistical methods(e.g. the linear regression models and variation partitioning), we analyzed the relative and pure effect of area, climate, and boundary constraint on elevational patterns of plant species diversity and climate and habitat heterogeneity on the elevational patterns of amphibian and reptile species diversity. The main results were summarized as follows:(1) that diversity of overall plant species and their different group species exhibited humped-shaped patterns and the peaks were below the middle domain of the elevational gradient;(2) The diversity of amphibian species exhibited a humped-shaped pattern and the peak was below the middle domain of the elevationalgradient,while the pattern of reptile diversity was increasing gradually with the increase of elevation;(3) The patterns were shaped by all kinds of factors together.The explanatory power of water-energy dynastic hypothesis for the pattern was the strongest. And area was a secondary factor which affects the patterns.(4)Boundary constraint effect was a complementary mechanism to explain the plant species diversity elevational patterns in the Baishuijiang Nature Reserve. The explanatory powers of boundary constraint for different-range species were clearly different.With the increase of species range, boundary constraint showed an increasingly strong correlation with species richness patterns;(5) The explanatory power of water-energy dynamic hypothesis was strong for shaping the patterns of amphibian and reptile species diversity in the Baishuijiang Natural Reserve, and there existed a stronger collinearity between water-energy dynamic hypothesis and habitat heterogeneity hypothesis. The variable, mean annual rainfall(PAN), was included in the final linear regression model of amphibian species diversity elevational patterns,but was not included in that of reptile species diversity elevational pattern. However,the variables, potential evapotranspiration(PET), was included in the final linear regression model of reptile species diversity elevational pattern. These results showed that water and temperature played a more important role in shaping the elevational patterns of amphibian and reptile than habitat heterogeneity did,respectively.