Relationships between geographic patterns of ant species richness and environmental factors in China

Understanding spatial patterns of species richness is a hot topic in macroecology because of its significance in biodiversity conservation. In many previous studies, current environmental variables representing energy and water availability have been considered as the main drivers of geographic diversity patterns. However,the roles of different environmental variables vary for different taxonomic groups and distinct biogeographic extents; therefore,there is no consensus among ecologists on which environmental variables are primary drivers of the spatial variation in species richness.China covers a wide range of latitudes and longitudes and has a wide range of variation in climate and vegetation( e.g.,from tropical rain forest in the south to boreal forest in the northwest and desert in the north and northwest). Thus,China offers great opportunity for testing the relationships between species richness and environment. In the present study,geographic pattern of ant species richness in China and its relationships with environmental factors were investigated based on ant distribution data and environmental variables at a provincial scale. Several studies on the distribution of ants in othergeographical areas show that temperature( energy) is the most important factor that determines ant species richness patterns.This conclusion might also apply to China. Therefore,four hypotheses were tested in the present study.( 1) Compared to the mean annual precipitation,ant species richness pattern was more likely affected by the mean annual temperature.( 2)Compared to the habitat heterogeneity associated with precipitation,ant species richness pattern was more affected by habitat heterogeneity associated with temperature. Since ants are ectotherms and their survivorship under low temperature in winter is critical for their populations and distribution,we further assumed that( 3) compared to the mean annual temperature,mean temperature of the coldest month better explains the spatial differentiation of ant species richness. Given that precipitation seasonality and temperature seasonality are mainly determined by annual temperature range and annual precipitation range,we inferred that,( 4) compared to precipitation seasonality,temperature seasonality can better explain spatial ant species richness pattern. To test these hypotheses,GIS was used to map ant species diversity and simple and multiple linear regressions were used to determine the relative roles of different envi