Context Theoretical models propose that the spatial extent at which landscape structure best predicts species responses (scale of effect, SoE) depends on habitat and dietary specialization, landscape metrics, and response variables. However, empirical support for such models is scarce, especially for apex predators. Objectives To determine SoE for diurnal raptors, and test for differences among ecological traits of habitat and dietary specialization, landscape metrics, and response variables. Methods We conducted 1.5 km transect surveys of diurnal raptors at 26 sites in a tropical dry forest from western Mexico. We measured four landscape metrics (forest cover, matrix hardness, forest patch density, edge density) in 16 concentric landscapes (400 to 3400 ha) around each survey site. We then assessed the landscape size at which each landscape metric best predicted each response variable (abundance, species richness, temporal beta diversity). Finally, we tested for differences in SoE among ecological traits of raptors, landscape metrics, and response variables. Results Landscape composition metrics of forest cover and matrix hardness decreased with increasing landscape size, and were the main landscape predictors influencing diurnal raptors. SoE differed significantly among landscape metrics, being larger for forest cover (2433.3 ha) than matrix hardness (1500 ha). However, SoE did not differ significantly among ecological traits of raptors, or response variables. Conclusions SoE was mainly driven by spatial metrics, with diurnal raptors being more strongly associated with forest cover measured over larger scales. This supports findings for other taxa and suggests that forest cover influences dispersal success across larger scales.

中文翻译：

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破碎的热带干旱森林景观结构对昼夜猛禽影响规模的模式和驱动因素

背景理论模型提出，景观结构最好地预测物种反应的空间范围（效应尺度，SoE）取决于栖息地和饮食专业化、景观指标和响应变量。然而，对此类模型的实证支持很少，尤其是对于顶级掠食者。目的 确定昼夜猛禽的 SoE，并测试栖息地生态特征和饮食专业化、景观指标和响应变量之间的差异。方法 我们在墨西哥西部热带干燥森林的 26 个地点对昼夜猛禽进行了 1.5 公里的横断面调查。我们在每个调查地点周围的 16 个同心景观（400 至 3400 公顷）中测量了四个景观指标（森林覆盖率、基质硬度、森林斑块密度、边缘密度）。然后，我们评估了每个景观指标最能预测每个响应变量（丰度、物种丰富度、时间 beta 多样性）的景观大小。最后，我们测试了猛禽的生态特征、景观指标和响应变量之间 SoE 的差异。结果森林覆盖和基质硬度的景观组成指标随着景观规模的增加而降低，是影响昼夜猛禽的主要景观预测因子​​。SoE 在景观指标之间存在显着差异，森林覆盖率（2433.3 公顷）大于基质硬度（1500 公顷）。然而，猛禽的生态特征或响应变量之间的 SoE 没有显着差异。结论 SoE 主要由空间指标驱动，昼夜猛禽与更大尺度上测量的森林覆盖率更密切相关。