Abstract
We studied the effects of habitat fragmentation, measured as forest stand size and isolation, on the distribution of Eurasian red squirrels (Sciurus vulgaris). Squirrel density was surveyed during four years in 46 forest stands (0.1–500 ha) in a forest landscape in south-central Sweden. The only factor that significantly influenced a density index was the proportion of spruce within a habitat fragment. Neither fragment size nor degree of isolation were significant. Furthermore, none of the interactions with year were significant, suggesting the same pattern in all four years. Thus, the effect of habitat fragmentation in this study seems to be only pure habitat loss, i.e. halving the proportion of preferred habitat in the landscape should result in a halving of the red squirrel population. Therefore, the landscape can be viewed as functionally continuous for the squirrels, although the preferred habitat was divided into fragments. The most likely explanation for the difference between this study and other studies on squirrels that found effects due to habitat fragmentation is a combination of shorter distances and less hostile surroundings in our study area. To identify landscape effects requires multiple studies because single studies usually consider only one landscape.
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References
Åberg, J., Jansson, G., Swenson, J.E. and Angelstam, P. 1995. The effect of matrix on the occurrence of hazel grouse (Bonasa bonasia) in isolated habitat fragments. Oecologia 103: 265–269.
Ahti, T., Hämet-Ahti, L. and Jalas, J. 1968. Vegetation zones and their sections in northwestern Europe. Ann. Bot. Fennici 5: 169–211.
Andrén, H. 1994. Effects of habitat fragmentation on birds and mammals in landscapes with different proportions of suitable habitat: a review. Oikos 71: 355–366.
Andrén, H. 1996. Population responses to habitat fragmentation: statistical power and the random sample hypothesis. Oikos 76: 235–242.
Andrén, H. 1997. Habitat fragmentation and changes in biological diversity. Ecol. Bull. 46: 171–181.
Andrén, H. and Delin, A. 1994. Habitat selection in the Eurasian red squirrel, Sciurus vulgaris, in relation to forest fragmentation. Oikos 70: 43–48.
Andrén, H. and Lemnell, P.-A. 1992. Population fluctuations and habitat selection in the Eurasian red squirrel Sciurus vulgaris. Ecography 15: 303–307.
Andrén, H., Delin, A. and Seiler, A. 1997. Population response to landscape changes depends on specialization to different landscape elements. Oikos 80: 193–196.
Apeldoorn, R. C. van, Celada, C. and Nieuwenhuizen, W. 1994. Distribution and dynamics of the red squirrel (Sciurus vulgaris L.) in a landscape with fragmented habitat. Landscape Ecol. 9: 227–235.
Arnqvist, G. and Wooster, D. 1995. Meta-analysis: synthesizing research findings in ecology and evolution. TREE 10: 236–240.
Bright, P. W., Mitchell, P. and Morris, P. A. 1994. Dormouse distribution: survey techniques, insular ecology and selection of sites for conservation. J. Appl. Ecol. 31: 329–339.
Celada, C., Bogliani, G., Gariboldi, A. and Maracci, A. 1994. Occupancy of isolated woodlots by the red squirrel Sciurus vulgaris L. in Italy. Biol. Cons. 69: 177–183.
Cohen, J. 1988. Statistical power for the behavioral sciences. Erlbaum Ass., Publ.
Connor, E. F. and McCoy, E. D. 1979. The statistics and biology of the species-area relationship. Am. Nat. 113: 791–833.
Esseen, P.-A., Ehnström, B., Ericson, L. and Sjöberg, K. 1997. Boreal forest. Ecol. Bull. 46: 16–47.
Haila, Y. 1983. Land birds on northern islands: a sampling metaphor for insular colonization. Oikos 41: 334–351.
Hansson, L. 1979. Field signs as indicators of vole abundance. J. Appl. Ecol. 16: 339–347.
Hayne, D. W. and Thompson, D. Q. 1965. Methods for estimating microtine abundance. Transactions of the 30th North American Wildlife Conference, pp. 393–400.
Hurlbert, S. H. 1984. Pseudoreplication and the design of ecological field experiments. Ecol. Monogr. 54: 187–211.
Hurrell, E. and McIntosh, G. 1984. Mammal society dormouse survey, January 1975-January 1979. Mammal Rev. 14: 1–18.
Lande, R. 1987. Extinction thresholds in demographic models of territorial populations. Am. Nat. 130: 624–635.
Southwood, T. R. E. 1977. Habitat, the templet for ecological strategies? J. Anim. Ecol. 4: 171–176.
Taylor, P. D., Fahrig, L., Henein, K. and Merriam, G. 1993. Connectivity is a vital element of landscape structure. Oikos 68: 571–573.
The Swedish National Board of Forestry. 1988. The basis of forestry. Jönköping, Sweden (in Swedish).
Verboom, B. and van Apeldoorn, R. C. 1990. Effects of habitat fragmentation on the red squirrel, Sciurus vulgaris L. Landscape Ecol. 46: 337–365.
Wauters, L., Casale, P. and Dhondt, A. A. 1994a. Space use and dispersal of red squirrels in fragmented habitats. Oikos 69: 140–146.
Wauters, L. A., Hutchinson, Y., Parkin, D. T. and Dhondt, A. A. 1994b. The effects of habitat fragmentation on demography and on the loss of genetic variation in the red squirrel. Proc. R. Soc. London. B. 255: 107–111.
Wright, D. H. 1991. Correlation between incidence and abundance are expected by chance. J. Biogeo. 18: 463–466.
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Delin, A.E., Andrén, H. Effects of habitat fragmentation on Eurasian red squirrel (Sciurus vulgaris) in a forest landscape. Landscape Ecology 14, 67–72 (1999). https://doi.org/10.1023/A:1008040001801
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DOI: https://doi.org/10.1023/A:1008040001801