Migration in geographic and ecological space by a large herbivore

Partial migration, when only part of the population migrates seasonally while the other part remains resident on the shared range, is the most common form of migration in ungulates. Migration is often defined by spatial separation of seasonal ranges and consequently, classification of individuals as migrants or residents is usually only based on geographic criteria. However, the underlying mechanism for migration is hypothesized to be movement in response to spatiotemporal resource variability and thus, migrants are assumed to travel an ‘ecological distance’ or shift their realized ecological niches. While ecological and geographic distances should be related, their relationship may depend on landscape heterogeneity. Here, we tested the utility of ecological niche theory to both classify migratory individuals and to understand the underlying ecological factors for migratory behavior. We developed an integrative approach combining measures in geographic and ecological niche space and use...

部分迁徙（即种群中仅有一部分个体进行季节性迁徙，其余个体则留居于共享栖息范围内）是有蹄类动物最常见的迁徙形式。迁徙通常以季节性栖息范围的空间分隔作为定义依据，因此对个体迁徙者与留居者的分类通常仅基于地理标准。然而，现有假说提出，迁徙的核心机制是个体响应时空资源动态变化的移动行为，因此迁徙者被认为会跨越「生态距离」，或是改变其实际生态位（realized ecological niche）。尽管生态距离与地理距离理应存在关联，但二者的关系可能取决于景观异质性。本研究旨在验证生态位理论在迁徙个体分类以及解析迁徙行为背后生态驱动因素两方面的应用价值。我们构建了一种整合地理与生态位空间度量指标的综合分析方法，并将……