贺兰山甲虫物种丰富度分布格局及其环境解释

理解山地物种丰富度分布格局及其成因对于山地生物多样性保护具有重要意义。本文基于贺兰山地区甲虫31科252属469种的分布信息, 结合相关气候与生境异质性数据, 系统地探讨了贺兰山地区甲虫及6个优势科物种丰富度地理格局及其影响因素。结果表明, 甲虫物种丰富度及科属区系分化强度以贺兰山中段最高, 南段比北段高, 西坡比东坡高。基于183个栅格内物种分布的二元数据聚类分析, 贺兰山甲虫分布可分为北段强旱生景观甲虫地理群、中西段半湿生景观甲虫地理群、中东段及南段半旱生景观甲虫地理群3个地理群。冗余分析(RDA)表明年均温和年均降水量是影响最显著的因子。方差分解结果显示, 水分与能量因子共同解释了全部甲虫物种丰富度57.1%的空间变异, 单独解释率分别为5.9%和7.1%。生境异质性解释了全部甲虫物种丰富度35.2%的变异, 单独解释率仅为1.8%。气候因素与生境异质性对不同优势科物种丰富度的相对影响并不一致。在贺兰山的南段和北段, 生境异质性和水分因子对甲虫物种丰富度影响作用明显。水分和能量因子是贺兰山地区甲虫物种丰富度空间分布格局的主导因子, 生境异质性有助于提高甲虫物种丰富度。从未解释的比例来分析, 地形和土壤因素可能对贺兰山甲虫物种丰富度存在重要影响。

Distribution patterns and environmental interpretation of beetle species richness in Helan Mountain of northern China

Spatial patterns of species richness and mechanism are vital to biodiversity conservation. Based on the distribution of beetles and combined the climate and habitat heterogeneity, we explored the distribution patterns and effect factors of beetle species richness of overall and six dominant families in Helan Mountain of northern China. The results showed that species richness and fauna differentiation intensity of beetles were the highest in the middle of Helan Mountain, the southern section was higher than the northern section, and the western section was higher than the eastern section. After clustering analysis of species distributed in 183 grids, the distribution of beetles could be classified into three groups (xerophilic landscape beetle groups in the northern section, semi-hygric landscape beetle groups in the middle-western section, and semi-xerophytic beetle groups in the middle-east and south section). The mean annual temperature and precipitation were the most significant factors on beetle distribution by analyzing of RDA. Meanwhile, water and energy factors together explained 57.1% of the spatial variation in overall beetle species richness, only 5.9% and 7.1% separately, followed by habitat heterogeneity (35.2%) and only 1.8% separately. The relative effect of dominant species richness were inconsistent with climatic and habitat heterogeneity, but water and habitat heterogeneity have significant effect on beetle species richness in southern and northern of Helan Mountain. Water and energy factors dominantly impacted beetle spatial distribution, and habitat heterogeneity increased the species richness. Therefore, we suggested that topographic and soil factors may also have an important influence on beetle species richness in Helan Mountain according to the unexplained proportion.