Altered natal dispersal at the range periphery: The role of behavior, resources, and maternal condition
AffiliationUniv Arizona, Sch Nat Resources & Environm, Wildlife Conservat & Management
Tamiasciurus hudsonicus grahamensis
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CitationAltered natal dispersal at the range periphery: The role of behavior, resources, and maternal condition 2017, 7 (1):58 Ecology and Evolution
JournalEcology and Evolution
Rights© 2016 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License.
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AbstractNatal dispersal outcomes are an interplay between environmental conditions and individual phenotypes. Peripheral, isolated populations may experience altered environmental conditions and natal dispersal patterns that differ from populations in contiguous landscapes. We document nonphilopatric, sex-biased natal dispersal in an endangered small mammal, the Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis), restricted to a single mountain. Other North American red squirrel populations are shown to have sex-unbiased, philopatric natal dispersal. We ask what environmental and intrinsic factors may be driving this atypical natal dispersal pattern. We test for the influence of proximate factors and ultimate drivers of natal dispersal: habitat fragmentation, local population density, individual behavior traits, inbreeding avoidance, competition for mates, and competition for resources, allowing us to better understand altered natal dispersal patterns at the periphery of a species' range. A juvenile squirrel's body condition and its mother's mass in spring (a reflection of her intrinsic quality and territory quality) contribute to individual behavioral tendencies for movement and exploration. Resources, behavior, and body condition have the strongest influence on natal dispersal distance, but affect males and females differently. Male natal dispersal distance is positively influenced by its mother's spring body mass and individual tendency for movement; female natal dispersal distance is negatively influenced by its mother's spring body mass and positively influenced by individual tendency for movement. An apparent feedback between environmental variables and subsequent juvenile behavioral state contributes to an altered natal dispersal pattern in a peripheral population, highlighting the importance of studying ecological processes at the both range center and periphery of species' distributions.
VersionFinal published version
SponsorsUnited States Forest Service; University of Arizona Agricultural Experiment Station; Joint Fire Sciences Program Graduate Research Innovations ; University of Arizona NASA Space Grant Consortium Fellowship; University of Arizona Institute of the Environment Carson Scholars Fellowship; American Society of Mammalogists; American Museum of Natural History Theodore Roosevelt Graduate Student Research Award; Southwestern Association of Naturalists Howard McCarley Student Research Award; T & E Inc. Grants for Conservation Biology