We investigated the role of local and landscape environmental variables on anurans density classified as habitat specialists and generalists in grassland landscapes, known as South Brazilian grasslands (SBG). In this region, we surveyed 187 ponds distributed over 40 landscape sampling units. For each pond, 31 local environmental variables were measured. Each landscape sampling unit was embedded within a larger regional sampling unit with different landscape properties. For each landscape and regional sampling units, 16 landscape metrics were extracted from a land cover and use map. We recorded 35 species, eleven of which are specialists in the SBG. The specialists were affected by 11 local and 2 landscape environmental variables, while generalists were affected by 14 local and one landscape environmental variable. Thus, specialists and generalists presented different relationships with local and landscape variables, but in general local variables had a greater influence on the density of anurans than the landscape variables. However, the landscape indirectly influenced local variables because higher quality ponds were in landscapes with higher percentages of natural habitat. In conclusion, reproductive sites with higher local quality and located within landscapes with higher percentages of natural grasslands are essential to conserve anurans in this habitat. Effective conservation of such sites would benefit from further studies that assess effects of land use and biotic integrity of ponds, which can help to determine (a) the relative effects of local habitat quality of ponds and (b) the effectiveness of protecting ponds and their local surroundings for anuran conservation in SBG.

中文翻译：

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亚热带草原上池塘尺度无脊椎动物密度与局部尺度和景观尺度之间的相互作用

我们调查了本地和景观环境变量在被称为南巴西草原（SBG）的草原景观中被划分为栖息地专家和通才的无脊椎动物密度上的作用。在该地区，我们对分布在40个景观采样单元中的187个池塘进行了调查。对于每个池塘，测量了31个局部环境变量。每个景观采样单元都嵌入具有不同景观属性的较大区域采样单元中。对于每个景观和区域采样单位，从土地覆盖和使用地图中提取了16个景观指标。我们记录了35种，其中11种是SBG的专家。专家受11个局部和两个景观环境变量的影响，而通才则受到14个局部和一个景观环境变量的影响。从而，专家和通才提出了与局部变量和景观变量的不同关系，但总的来说，局部变量对无色菌密度的影响大于景观变量。但是，景观质量间接影响了局部变量，因为高质量的池塘位于自然栖息地百分比较高的景观中。总而言之，具有较高本地品质的生殖场所和自然草原所占比例较高的景观对保护该栖息地的无核动物至关重要。评估土地利用和池塘生物完整性的影响的进一步研究将有益于有效保护这些地点，