Abstract European semi-natural grasslands host numerous and diverse living organisms within a relatively small area; therefore, conservation of these habitats is crucial to maintain high biodiversity in agricultural areas. The aim of this study was to examine the effects of environment, habitat continuity and spatial structure on semi-natural grassland species richness (SR) at the regional extent. SR and characteristic SR (CHSR) were calculated in 709 georeferenced vegetation plots obtained from the Polish Vegetation Database. For each vegetation plot, (1) environmental variables representing climate, topography, soil characteristics (e.g. pH and physical soil properties), landscape and anthropogenic pressure; (2) habitat continuity in time and (3) variables reflecting the spatial structure of vegetation plots using principal coordinates of neighbour matrices were measured. Environmental data were measured at four different spatial scales (buffers of 0.05-, 0.5-, 2.5- and 5-km radii surrounding each vegetation plot). Boosted regression trees were generated to explore the relationships of SR and CHSR with predictors. Variables associated with anthropogenic pressure, landscape structure and soil characteristics operating in the 0.5- and 5-km buffers significantly improved SR and CHSR model. However, effects of individual predictors on SR and CHSR were not predominant. Habitat continuity and topographic heterogeneity operating in the 0.05-km buffer exclusively improved CHSR model. The results suggest that neutral processes (dispersion limitation, local management history and/or stochastic events) reflected by spatial variables are strongly related to SR and CHSR. Patterns observed herein may also exist in other agriculture-dominated regions in temperate Europe. This knowledge will contribute to effective conservation of valuable habitats over large spatial areas.

中文翻译：

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环境梯度、生境连续性和空间结构对半天然草地维管植物物种丰富度的影响

摘要 欧洲半天然草原在相对较小的区域内拥有众多多样的生物；因此，保护​​这些栖息地对于维持农业地区的高度生物多样性至关重要。本研究的目的是研究环境、栖息地连续性和空间结构对区域范围内半天然草地物种丰富度 (SR) 的影响。SR 和特征 SR (CHSR) 是在从波兰植被数据库获得的 709 个地理参考植被图中计算的。对于每个植被地块，(1) 代表气候、地形、土壤特征（例如 pH 值和土壤物理特性）、景观和人为压力的环境变量；(2) 栖息地的时间连续性和 (3) 使用相邻矩阵的主坐标反映植被地块空间结构的变量。环境数据在四个不同的空间尺度（每个植被区周围半径为 0.05-、0.5-、2.5- 和 5-km 的缓冲区）进行测量。生成增强回归树以探索 SR 和 CHSR 与预测变量的关系。在 0.5 公里和 5 公里缓冲区中运行的与人为压力、景观结构和土壤特征相关的变量显着改善了 SR 和 CHSR 模型。然而，个体预测因子对 SR 和 CHSR 的影响并不占优势。在 0.05 公里缓冲区中运行的栖息地连续性和地形异质性专门改进了 CHSR 模型。结果表明中性过程（分散限制，空间变量反映的本地管理历史和/或随机事件与 SR 和 CHSR 密切相关。在此观察到的模式也可能存在于温带欧洲的其他以农业为主的地区。这些知识将有助于在大空间区域有效保护宝贵的栖息地。