Species composition and community structure of dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) compared among savanna and forest formations in the southwestern Brazilian Cerrado

ABSTRACT Although dung beetles are important members of ecological communities and indicators of ecosystem quality, species diversity, and how it varies over space and habitat types, remains poorly understood in the Brazilian Cerrado. We compared dung beetle communities among plant formations in the Serra Azul State Park (SASP) in the state of Mato Grosso, Brazil. Sampling (by baited pitfall and flight-interception traps) was carried out in 2012 in the Park in four habitat types: two different savanna formations (typical and open) and two forest formations (seasonally deciduous and gallery). A total of 5,400 individuals collected comprised 57 species in 22 genera. Typical savanna had the greatest species richness and abundance, followed by open savanna and deciduous forest, while the gallery forest had the fewest species but high abundance. Tunnelers (one of three main nesting behavior guilds) showed the greatest richness and abundance (except in the gallery forest, where one dweller species was extremely abundant) in all plant formations. We found that species richness and abundance of the dung beetle community are influenced by differences among plant formations. Habitat heterogeneity in the different plant formations along with anthropic influences (fire, habitat fragmentation) are cited as important factors that explain guild and species richness and distribution patterns. These results emphasize the importance of protected areas, such as SASP, for the maintenance and conservation of species diversity in the Brazilian Cerrado.

摘要 尽管蜣螂是生态群落的重要组成类群，同时也是生态系统质量的指示物种，但巴西塞拉多（Brazilian Cerrado）地区的蜣螂物种多样性及其随空间与生境类型的变化规律仍未得到充分研究。本研究以巴西马托格罗索州蓝山国家公园（Serra Azul State Park, SASP）为研究区域，对比分析了该区域内不同植被型的蜣螂群落特征。2012年，研究团队于该公园内选取4类生境开展采样工作，采样采用诱饵陷阱法（baited pitfall trap）与飞行拦截陷阱法（flight-interception trap）；所涉及的生境包括2种稀树草原植被型（典型稀树草原与开阔稀树草原）以及2种森林植被型（季节性落叶林与河岸林）。本次采样共采集到蜣螂个体5400头，隶属于22属57种。典型稀树草原的物种丰富度与个体丰度均为最高，其次为开阔稀树草原与季节性落叶林；河岸林的物种数最少，但个体丰度较高。掘洞类蜣螂（三大主要筑巢行为功能群（guild）之一）在所有植被型中均表现出最高的物种丰富度与个体丰度，仅河岸林例外——该生境中某一居住类蜣螂物种的个体数量极为庞大。本研究证实，蜣螂群落的物种丰富度与个体丰度受植被型差异的显著影响。不同植被型的生境异质性，加之人为干扰因素（火灾、生境破碎化），是解释功能群与物种丰富度分布格局的关键驱动因素。本研究结果凸显了蓝山国家公园（SASP）这类保护区，对于维持与保护巴西塞拉多地区物种多样性的重要意义。