Woodland fragmentation affects space use of Eurasian red squirrels

Verbeylen, Goedele; Wauters, Luc A.; Bruyn, Luc De; Matthysen, Erik

doi:10.1016/j.actao.2008.08.005

Cited by 27 publications

(23 citation statements)

References 52 publications

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“…Measured resources may vary from hostplant density for butterflies (e.g., Heisswolf et al 2009) to den availability (e.g., Virgos 2001) and food abundance (e.g., Schooley and Branch 2007;Mortelliti and Boitani 2008;Verbeylen et al 2009). Provided that the experimental design and the subsequent analysis allow the researcher to (1) separate the independent contribution of resources from the role of the geometry of the patch and (2) subsequently test for the interaction between resources in the patch and the geometrical features, the measurement of resources as a proxy for patch quality may be a good compromise in many cases.…”

Section: Measurements Of Patch Quality and Scope Of The Studiesmentioning

confidence: 99%

The role of habitat quality in fragmented landscapes: a conceptual overview and prospectus for future research

2010

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There is increasing empirical evidence that the quality of habitat patches (determined by either habitat degradation or natural heterogeneity in the quality of habitat) plays an important role in determining species distribution patterns and in regulating spatial dynamics in fragmented landscapes. However, to date, most of the debate has focused on whether or not to include habitat variables in fragmentation studies, and we still lack general conclusions as well as standard and robust research approaches. In this paper we show how a weak conceptualization of "patch quality" and the inappropriate choice of target surrogate variables (e.g., density is often used as an indicator of patch quality) have mainly produced case-specific results, rather than general conclusions. We then identify weaknesses in the inclusion of habitat quality measurements within fragmentation studies. In particular, we focus on: (1) the lack of appropriate experimental design, outlining how few studies have actually included a gradient of habitat quality in their sample; (2) the lack of fundamental information provided (e.g., lack of standard outputs), which in turn hampers the possibility of carrying out meta-analyses. We finally synthesize available knowledge from empirical studies and highlight the different conceptual frameworks needed for patch occupancy versus patch use studies.

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Section: Measurements Of Patch Quality and Scope Of The Studiesmentioning

confidence: 99%

The role of habitat quality in fragmented landscapes: a conceptual overview and prospectus for future research

2010

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“…Pregnant and/or lactating females were radio-collared using SR-1 and TW-4 transmitter collars (±12 g, 9 and 18 months lifetime, respectively; Biotrack, Wareham, UK) to locate the nursing nest . We used the minimum number of animals known to be alive (MNA), from trapping, radio-tracking or observations, as our estimate of population density (Verbeylen et al 2003(Verbeylen et al , 2009Wauters et al 2004). This allowed us to determine densities encountered before and after dispersal for those squirrels that left the natal woodland in site SKW.…”

Section: Study Sitesmentioning

confidence: 99%

“…In all patches, squirrels had access to hazel, Corylus avellana, shrubs. In each study site, woodland quality (WQ; Table 1) was estimated as the sum of the percentage of important food-producing trees for squirrels (Scots and Corsican pine, Norway spruce, oak, beech, larch, and sweet chestnut; see also Wauters et al 1994a;Verbeylen et al 2003Verbeylen et al , 2009). …”

Section: Study Sitesmentioning

confidence: 99%

Dispersal and habitat cuing of Eurasian red squirrels in fragmented habitats

et al. 2010

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Animal dispersal and subsequent settlement is a key process in the life history of many organisms, when individuals use demographic and environmental cues to target post-dispersal habitats where fitness will be highest. To investigate the hypothesis that environmental disturbance (habitat fragmentation) may alter these cues, we compared dispersal patterns of 60 red squirrels (Sciurus vulgaris) in three study sites that differ in habitat composition and fragmentation. We determined dispersal distances, pre-and post-dispersal habitat types and survival using a combination of capture-mark-recapture, radiotracking and genetic parentage assignment. Most (75%) squirrels emigrated from the natal home range with mean dispersal distance of 1,014 ± 925 m (range 51-4,118 m). There were no sex-related differences in dispersal patterns and no differences in average dispersal distance, and the proportion of dispersers did not differ between sites. In one of the sites, dispersers settled in patches where density was lower than in the natal patch. In the least fragmented site, 90% of animals settled in the natal habitat type (habitat cuing) against 44-54% in the more strongly fragmented sites. Overall, more squirrels settled in the natal habitat type than expected based on habitat availability, but this was mainly due to individuals remaining within the natal wood. In the highly fragmented landscape, habitat cuing among emigrants did not occur more frequently than expected. We concluded that increased habitat fragmentation seemed to reduce reliable cues for habitat choice, but that dispersing squirrels settled in patches with lower densities of same-sex animals than at the natal home range or patch, independent of degree of fragmentation.

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“…Habitat loss and destruction have been found in extensive research to strongly affect S. vulgaris generally (Wauters et al 1994;Verbeylen et al 2003Verbeylen et al , 2009, with sensitivity to habitat fragmentation especially emphasized, for instance, by Koprowski (2005). Mortelliti et al (2011) argued instead that what matters is habitat loss, not fragmentation per se.…”

Section: Conservation and Research Prioritiesmentioning

confidence: 99%

Grey squirrels in central Italy: a new threat for endemic red squirrel subspecies

2014

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A new population of the invasive American Eastern grey squirrel (Sciurus carolinensis) has recently settled in central Italy from an accidental release in Perugia, Umbria in the early 2000s. The grey squirrel is known to compete with and exclude native red squirrels (S. vulgaris) in the British Isles and Northern Italy, so it represents a potentially important new conservation threat to the red squirrel subspecies of south and central Italy, S. vulgaris italicus and S. v. meridionalis, which are endemic to peninsular Italy. The grey squirrel population range in Perugia is currently expanding at a rate of about 0.29 km/year (SD 0.19), slower than grey squirrel invasions elsewhere in Europe. Nuclear DNA analysed at 12 different microsatellite loci revealed that the grey squirrels in Perugia have extremely low genetic diversity, consistent with a small founder size. Genetic assignment tests indicate that the Perugia population was founded by translocations from an established population in Piedmont, Italy. No genetic substructure is evident yet in the Perugia population. These results together have serious consequences for the management of the grey squirrel invasion in Perugia and the conservation of the red squirrel subspecies: the Perugia grey squirrel population should be eradicated if politically feasible; otherwise new releases of grey squirrels, especially from sources other than the Piedmont population, should be prevented because such introductions could increase genetic diversity, thereby potentially increasing population range expansion rate to the much higher levels seen for more diverse grey squirrel populations elsewhere in Europe.

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Woodland fragmentation affects space use of Eurasian red squirrels

Cited by 27 publications

References 52 publications

The role of habitat quality in fragmented landscapes: a conceptual overview and prospectus for future research

The role of habitat quality in fragmented landscapes: a conceptual overview and prospectus for future research

Dispersal and habitat cuing of Eurasian red squirrels in fragmented habitats

Grey squirrels in central Italy: a new threat for endemic red squirrel subspecies

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