Dispersal in Small Mammals

Gaines, and M S; McClenaghan, Leroy R.

doi:10.1146/annurev.es.11.110180.001115

Cited by 439 publications

(285 citation statements)

References 93 publications

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“…High rice rat abundance may force individuals to move into suboptimal cover to avoid indirect and direct competition Permeability is indicated by the slope of logit (capture rate) with distance from the wetland edge. Tests and slope estimates are from mixed-model logistic regression, using random effects to account for nonindependence based on wetland sublocation, trap line, and trap station from other rice rats (Gaines and McClenaghan 1980). Like Kruchek (2004), we found that subadults were disproportionately captured in the matrix compared to adults, which may be the result of resource partitioning or natal dispersal in the species.…”

Section: Discussionsupporting

confidence: 54%

“…Movement through agriculture fields could produce a kind of ecological trap, where animals readily enter a cover type despite an increased risk of mortality (Fahrig 2007). For a species adapted to semi-aquatic environments and their surrounding uplands, agriculture may ultimately prevent successful dispersal if rice rats face greater predation or starvation in crop fields than in native cover types (Gaines and McClenaghan 1980). In southern Illinois, Eubanks et al (2011) found that wetland patches surrounded by agriculture were less likely to be occupied by rice rats than those surrounded by upland grasses, but survival rates have not been explicitly compared between wetland and matrix areas.…”

Section: Discussionmentioning

confidence: 99%

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Comparing permeability of matrix cover types for the marsh rice rat (Oryzomys palustris)

2015

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Context Matrix land cover types differ in permeability to animals moving between habitat patches, and animals may actually move faster across lesssuitable areas. Marsh rice rats are wetland specialists whose dispersal crosses upland matrix. Objectives Our objectives were to (1) compare matrix permeability for the marsh rice rat among upland cover types, (2) compare permeability within versus outside perceptual range of the wetland, and (3) explore intrinsic and extrinsic features influencing matrix use and permeability. Methods We quantified permeability of grassland, crop field, and forest to the marsh rice rat during 2011-2012, by marking rats in wetlands and estimating the slope of capture rate versus distance (0-95 m) into the matrix. We also compared permeability within (0-15 m) and beyond the perceptual range of rice rats, and tested whether age, sex, time, water depth, rice rat abundance, and vegetation density influenced matrix use and permeability. Results Permeability was greater for soybean fields than grassland or forest but did not appear to differ within versus beyond rice rats' perceptual range. Matrix capture rates were higher early in the study and in times and locations with thick ground vegetation and high rice rat abundance in the wetlands. Rice rats captured in the matrix were younger than those in wetland patches. Conclusions Our findings expand known matrix use by marsh rice rats, and support permeability being high in matrix types dissimilar to suitable habitat. Studying individual movements will help identify mechanisms underlying enhanced permeability in crop fields.

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Section: Discussionsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 99%

Comparing permeability of matrix cover types for the marsh rice rat (Oryzomys palustris)

2015

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“…Consequently, functional connectivity covers situations where organisms venture into non-habitat (matrix), where they may (1) face higher mortality risks (e.g., Gaines and McGlenaghan 1980;Henein and Merriam 1990;Poole 1997;Sakai and Noon 1997), (2) express different movement patterns (e.g., Baars 1979;Wallin and Ekbom 1988;Wegner and Merriam 1990;Hansson 1991;Johnson et al 1992a;Andreassen et al 1996b;FitzGibbon et al 2007), and (3) cross boundaries (e.g., Mader 1984;Wiens et al 1985;Duelli et al 1990;Mader et al 1990;Mauremooto et al 1995;Sakai and Noon 1997;Walker et al 2007). Goodwin (2003) subdivides these two basic groups further into 10 subcategories, which are: presence or absence of corridors, distances, amount of habitat, contagion or percolation, dispersal success, graph theory, movement probability, searching time for a new habitat, reobservation of displaced individuals, immigration rate.…”

Section: From Intuitive Definitions To Basic Categorizationmentioning

confidence: 99%

Connectivity measures: a review

2008

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One of the central problems in contemporary ecology and conservation biology is the drastic change of landscapes induced by anthropogenic activities, resulting in habitat loss and fragmentation. For many wild living species, local extinctions of fragmented populations are common and recolonization is critical for regional survival. Successful recolonization depends on the availability of dispersing individuals and the degree of landscape connectivity. The obvious implications of landscape connectivity for conservation biology have led to a proliferation of connectivity measures. However, general relationships between landscape connectivity and landscape structure are lacking, and so are the relationships between different connectivity metrics. Consequently, there is a need to develop landscape metrics that more accurately characterize the landscape with an emphasis on the underlying processes. Here we review various definitions of landscape connectivity, explain their mathematical connotations, and make some unifying conclusions and suggestions for future research.

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“…A migrant faces increased risks of exposure, predation and disease; lack of familiarity with an area may reduce foraging efficiency; and resident conspecifics may attack strangers more severely than familiar individuals. Among small mammals, at least, it is likely that these risks are too much for most dispersers, and mortality rates among emigrants are usually high (reviewed by Gauthreaux 1978;Gaines & McClenaghan 1980). The demonstration of potential costs and benefits to both inbreeding and outbreeding has led to the concept of optimal outbreeding (or optimal inbreeding), reviewed by Bateson (1983) and Shields (1982b); the latter has even suggested that philopatry may have evolved to promote optimal inbreeding.…”

Section: Inbreeding Depression Inbreeding Costs and Benefitsmentioning

confidence: 99%

“…The presenc~ or absence of behavioural inbreeding avoidance can thus be viewed as a test of optimality reasoning analogous to that presented by Rothstein (1982), or, if we assume optimality, as evidence for or against the inbreeding-avoidance hypothesis of dispersal. Dispersal is costly (see Gauthreaux 1978;Harcourt 1978;Gaines & McClenaghan 1980), whereas kin recognition and behavioural incest avoidance presumably are not. If inbreeding is costly and behaviour is optimized by natural selection, we would therefore expect to find behavioural avoidance rather than demographic dispersal as a mechanism for avoiding inbreeding.…”

Section: Kin Recognitionmentioning

confidence: 99%

Are dispersal and inbreeding avoidance related?

1984

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Abstract. Sex differences in dispersal and inter-group transfer by birds and mammals are often considered to be evolved responses to the phenomenon of inbreeding depression. This belief is derived from 'natural selection logic', which holds that (1) because inbreeding depression is demonstrably costly, selection must have acted to minimize its occurrence, and (2) as sex differences in dispersal often appear to be the only thing preventing inbreeding, these sex differences must be the expected adaptations for avoiding inbreeding depression. However, although the sex differences in median dispersal distance observed among many small mammals and birds may reduce average levels of inbreeding within a population, they nevertheless leave the majority of individuals 'at risk' for inbreeding; such differences can be responses to inbreeding depression only in a group selection model. Furthermore, natal dispersal by both sexes occurs in many group-living species. In these species, emigration by individuals of one sex cannot easily be attributed to avoiding inbreeding because opposite-sex relatives also emigrate. Though most authors acknowledge that sexual dispersal patterns may be epiphenomenal consequences of other factors (e.g. intrasexual aggression), this point is rarely considered further. In this paper we critically review several frequently cited examples of differential dispersal, and conclude that 'other factors', such as intrasexual competition and territory choice, explain these observations more completely and consistently than does the inbreeding avoidance hypothesis. Observed dispersal patterns simply reflect sex differences in the balance between the advantages of philopatry and the costs of intrasexual competition.

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Dispersal in Small Mammals

Cited by 439 publications

References 93 publications

Comparing permeability of matrix cover types for the marsh rice rat (Oryzomys palustris)

Comparing permeability of matrix cover types for the marsh rice rat (Oryzomys palustris)

Connectivity measures: a review

Are dispersal and inbreeding avoidance related?

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