Flesch Aaron D
School of Natural Resources and the Environment, University of Arizona, The Desert Laboratory, 1675 Anklam Road, Tucson, AZ 85745, USA
Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA.
Proc Biol Sci. 2017 Jul 12;284(1858). doi: 10.1098/rspb.2017.1001.
In spatially structured populations, distributional dynamics are driven by the quantity, connectivity and quality of habitat. Because these drivers are rarely measured directly and simultaneously at relevant scales, information on their relative importance remains unclear. I assessed the influence of both direct and indirect measures of local habitat quality, and of landscape habitat amount and connectivity on long-term territory occupancy dynamics of non-migratory pygmy owls. Direct measures of local habitat quality based on territory-specific reproductive output had greater effects on distribution than landscape factors, but only when spatio-temporal fluxes in performance linked to environmental stochasticity and intraspecific competition were considered. When habitat quality was measured indirectly based on habitat structure, however, landscape factors had greater effects. Although all landscape factors were important, measures of landscape connectivity that were uncorrelated with habitat amount and based on attributes of matrix structure and habitat configuration that influence dispersal movements had greater effects than habitat effective area (amount weighted by quality). Moreover, the influence of connectivity (but not habitat effective area) depended on local habitat quality. Such results suggest the relative importance of local habitat quality in driving distribution has been underestimated and that conservation strategies should vary spatially depending on both local and landscape contexts.
在空间结构种群中，分布动态受栖息地的数量、连通性和质量驱动。由于这些驱动因素很少在相关尺度上直接且同时进行测量，关于它们相对重要性的信息仍不明确。我评估了当地栖息地质量的直接和间接测量指标，以及景观栖息地数量和连通性对非迁徙侏儒猫头鹰长期领地占据动态的影响。基于特定领地繁殖产出的当地栖息地质量直接测量指标对分布的影响比景观因素更大，但前提是要考虑与环境随机性和种内竞争相关的性能时空变化。然而，当基于栖息地结构间接测量栖息地质量时，景观因素的影响更大。尽管所有景观因素都很重要，但与栖息地数量不相关且基于影响扩散运动的基质结构和栖息地配置属性的景观连通性测量指标，其影响比栖息地有效面积（按质量加权的数量）更大。此外，连通性（而非栖息地有效面积）的影响取决于当地栖息地质量。这些结果表明，当地栖息地质量在驱动分布方面的相对重要性被低估了，保护策略应根据当地和景观背景在空间上有所不同。
