Macroecology is concerned with changes in biodiversity as well as the causes of these changes on large scales. Biodiversity can show changes over time and over space. Species diversity, as the determinant of biodiversity, shows spatial heterogeneity. China has high biodiversity. An increasing number of scientists are interested in the large-scale spatial variation in biodiversity within China. The natural environments in China have clear boundaries, which have influence the distributions of animals and ecosystems. According to climate type, China can be divided into three natural regions: the eastern monsoon region, the northwest arid region and the Qinghai-Tibetan Plateau region. Study of the spatial pattern of the biodiversity found in China may contribute to the understanding of large-scale patterns in biodiversity.
The fauna information database (FID), founded by the Wildlife and Behavioral Ecology Research Group, Institute of Zoology, Chinese Academy of Sciences, contains information on the distribution of amphibians, reptiles, birds and mammals in China. The FID was compiled with data on species checklists of amphibians, reptiles, birds and mammals from 205 nature reserves across mainland China. They covered most parts of the country except Jiangsu Province, Taiwan, Hong Kong and Macau.
In this study, we explored the spatial variation in the G-F indices of birds and mammals with geostatistical techniques. As a measure of species diversity, we computed the G-F index using data on birds and mammals in the FID. The G-F index, based on the Shannon-Wiener index, provides a standardized measure of the diversity of species of common origin and similar environmental requirements. We treated the G-F index as a regional variable and obtained semivariance models and parameters of birds and mammals individually for each of the three natural regions. Semivariograms were produced using semivariance analysis methods of GS-plus software. Using the semivariograms and model parameters, we analyzed the characteristics of the spatial variation in bird and mammal diversity in each natural region.
The semivariance of the G-F index of birds was fitted with a linear model in the eastern monsoon region and the northwest arid region of China. The parameters demonstrated that species diversity of birds had a weak spatial dependence in the eastern monsoon region and the northwest arid region of China. There was no spatial correlation with pure nugget effects on the Qinghai-Tibetan Plateau, indicating that the spatial variation in bird species diversity was caused by random factors. This may be due to the high dispersal abilities of birds. The semivariance of the G-F index of mammals showed no relationship in the eastern monsoon region and had pure nugget effects in the northwest arid region. However, data of the Qinghai-Tibetan Plateau was best explained by a spherical model. The parameters revealed that spatial pattern of mammalian species diversity was random in the eastern monsoon region and in the northwest arid region but had a strong spatial dependence with a correlation spatial range of 71492-1020000 m on the Qinghai-Tibetan Plateau. This spatial pattern of avian and mammalian species diversity is likely attributable to the interaction between the particular physical environment and life history of birds and mammals. The macroscale spatial pattern of species diversity should be taken into account in the formation of conservation action plans.