关键词: 露水量, 黄土丘陵区, 降雨, 气象因子

Abstract: Elevational patterns of species richness and species range size and their underlying mechanisms have long been one of controversial issues in biogeography and biodiversity. Elevational Rapoport’s rule believes that the species richness gradually declines with increasing elevation, while the species ranges become larger. In this paper, we analyzed the elevational patterns of herpetofaunal (including amphibians and reptiles) species richness and species range in Baishuijiang Reserve by use of the herpetofaunal elevationdistribution dataset. Meanwhile, we examined the relationships between species richness and their distributional middle point in elevational content for different groups, faunas and taxonomic units and tested the Rapoport’s rule by using general four methods, which were Stevens’ method, Pagel’s method, mid-point method and cross-species method, respectively. The results suggested that herpetofaunal species richness declined monotonically with increasing elevation in Baishuijiang Reserve, which conformed the elevational Rapoport’s rule. Water availability might be the most important environmental factor determining amphibian species richness whereas temperature tends to be more important to reptile species richness, which is consistent with different physiological requirements of the two groups of organisms. The highest proportions of herpetofauna, especially small-range species were found at the lower elevational bin. Therefore, more attention to protect herpetofaunal species should be paid in the lower elevational bin. The consequences to test Rapoport’s rule by Stevens’ method, Pagel’s method and cross-species method conformed the Rapoport’s rule. However, the results by midpoint method rejected the Rapoport’s rule and suggested a unimodal model because of mid-domain effect. Hence, mythology has a massive effect on testing Rapoport’s rule. Tests of Rapoport’s rule are limited by methodological considerations, and various comparisons among empirical tests are needed in order to generate conclusive insight into elevational patterns of species range size, and the mechanism shaping such patterns.

Key words: meteorological factors, dew amount, rainfall, loess hilly region.