Abstract Much of the Brazilian savanna (known locally as the Cerrado) has been converted to pasture of African C4 grasses (exotic pastures) for livestock production. The resulting habitat simplification and decreased resource availability may be significant factors underlying the impact on some soil arthropod groups, although it is still unclear how the different soil groups respond to this impact in the Brazilian savanna. We sampled epigeic arthropods in exotic pastures, adjacent woodland savanna fragments (cerrado sensu stricto), and savanna-pasture boundaries to investigate the impact of pasture on their diversity and activity, identifying the arthropods that contribute most to the between-habitat dissimilarities and those most vulnerable to pasture implementation. We also estimated the contribution of native and exotic plants to the diets of frequently observed arthropods in each habitat using carbon and nitrogen stable isotope analysis. We found lower richness and diversity of epigeic arthropods in pastures, where we also observed decreased activity of predator groups, whereas the activity of Symphypleona and Poduromorpha springtails increased. Springtail orders and Myrmicinae morphospecies were the main contributors to the between-habitat dissimilarities. Staphylinidae, Ptiliidae, and Zodariidae morphospecies seem to be vulnerable to exotic pastures. Our isotopic models show that woodland savanna arthropods feed preferentially on native C3-plant sources, while also showing signs of exotic C4 sources in their diet. These outcomes indicate that foraging or dispersal events may occur between habitats since arthropods captured in pastures also show signs of native sources in their diet.

中文翻译：

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巴西中部稀树草原外来牧场对表生节肢动物多样性的影响以及本地和外来植物来源对其饮食的贡献

摘要 巴西大草原（当地称为 Cerrado）的大部分地区已转变为非洲 C4 草（外来牧场）的牧场，用于畜牧生产。由此产生的栖息地简化和资源可用性下降可能是对某些土壤节肢动物群产生影响的重要因素，尽管目前尚不清楚不同土壤群如何对巴西稀树草原的这种影响做出反应。我们对异国牧场、邻近林地稀树草原碎片 (cerrado sensu stricto) 和稀树草原-牧场边界中的表生节肢动物进行采样，以研究牧场对其多样性和活动的影响，确定对生境间差异贡献最大的节肢动物和对栖息地差异影响最大的节肢动物容易受到牧场实施的影响。我们还使用碳和氮稳定同位素分析估计了本地和外来植物对每个栖息地中经常观察到的节肢动物饮食的贡献。我们发现牧场上表生节肢动物的丰富度和多样性较低，我们还观察到捕食者群体的活动减少，而 Symphypleona 和 Poduuromorpha 跳尾动物的活动增加。跳虫目和 Myrmicinae 形态种是造成生境间差异的主要因素。Staphylinidae、Ptiliidae 和 Zodariidae 形态种似乎容易受到外来牧场的影响。我们的同位素模型表明，林地稀树草原节肢动物优先以本地 C3 植物来源为食，同时也在其饮食中显示出外来 C4 来源的迹象。