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Habitat richness affects home range size in the red fox Vulpes vulpes
BEHAVI~U~~AL PROCESSES
ELSEVIER
Behavioural Processes 36 (1996) 103-106
Short Report
Habitat richness affects home range size in the red fox Vulpes vulpes M. Lucherini, S. Lovari
*
Department of Evolutionary Biology, Ethology and Behavioural Ecology Group, University of Siena, Via Mattioli 4, 53100 Siena, Italy Accepted
17 March 1995
Abstract The spatial behaviour of the red fox Vulpes dpes shows a great flexibility (Voigt and Macdonald, 1984). Home range size varies from 10 to over 5000 ha (Macdonald, 1987; Voigt, 1987). In carnivores, variations in home range size, weighed for body mass (Gittleman and Harvey, 1982), are largely related to differences in habitat productivity, but the intraspecific local variation in home range size can be only partially explained by differences in productivity. Macdonald (1981, 1983) suggested that home range size and configuration were determined in the red fox by the dispersion of food-rich patches. More recently, it has been found that (a) where humans are intolerant to the fox, resting sites are often located peripherally in home ranges (Meia and Weber, 1993); (b) the ranging behaviour of red foxes cannot be explained only by the features of food resources in a complex environment with several productive habitats (Cavallini and Lovari, 1994); and (c) home range size may be directly related to the distance between rest sites and food patches (Lucherini et al., in press). In this paper, evidence for a strong influence of habitat richness on home range size of the red fox is reported. Keywords: Red fox; Ranging behaviour;
Habitat richness
1. Introduction In the course of an &year-long study on the red fox in a Mediterranean coastal area, 13 adult (i.e. > 1 year old) foxes were neck-snared and radio-tagged. Foxes were caught in 3 ecologically different, adjacent areas of the Maremma Natural Park (10000 ha), Central Italy: coastal ecotone (3 males, 2 females); pinewood (Pinus pinaster and P. domestica) (3 males, 1 female); rural ecotone (2 males, 2 females). Study areas, trapping and radio-tracking materials and procedures have been described in detail elsewhere (coastal ecotone: Cavallini and Lovari, 1991 and 1994; pinewood: Lovari et al.,
* Corresponding
author.
0376-6357/%/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSDI 0376-6357(95)00018-6
104
M. Luchrrini, S. Loucrri/ Brhaoiourai Procrsses 36 (1996) 103-106
0.
.
.. 1
0
.02
.04 .06
.08
.I
.12
.I4
N habitats/ha Fig. I. Exponential regression between home range size (ha) of 13 adult red foxes from three different adjacent areas and habitat richness within their respective home ranges (y = 73.52+e (‘.03- ‘O’.“); R = 0.91). Data on home ranges are from Cavallini and Lovari, 1994; Lovari et al., 1994; Lucherini et al., in press.
1994; rural ecotone: Lucherini et al., in press). All foxes were intensively radio-tracked (mean number of fixes/individual = 1067; range = 153-3 140) for 12-48 h/week/animal. In all cases, fixes were evenly distributed during the 24 h. For the aims of our study, we have not looked for statistical independence of fixes (Swihart and Slade, 19851, but for their biological independence (e.g. Lair, 1987), using a minimum time interval between successive locations (15 min) long enough to allow any radio-tagged fox to cross entirely its home range. Home range size has been estimated with the 100% minimum convex polygon (Mohr, 1947). Habitat richness has been calculated in the home range of each fox as the number of habitats/ha. Single habitats were defined in terms of salient vegetation types, e.g. vineyards vs. olive groves or pinewood. The negative correlation between home range size and habitat richness found within our rural area (Lovari et al., in press) generated the question whether this relation was limited to the local situation or could be general. Since home range size showed no significant difference between sexes (2-tailed t-test: t = 1.12; d.f. = 11; P = 0.291, data of all individuals from the 3 areas have been pooled. The negative regression between home range size and habitat richness was highly significant (P = 0.0001). An exponential model explained 83% of the variance in home range sizes (Fig. 1). Home range size of such an adaptable carnivore may be influenced by a number of variables: e.g. food patch dispersion (Macdonald, 198 1, 19831, territory defence costs (Doncaster and Macdonald, 1992), concentration of food resources (Lovari et al., 1994), rest site location (Lucherini et al., in press). In an heterogeneous environment, where each habitat provides the fox with a specific set of resources, habitat richness, as measured here, is likely related to the diversity of resources within each territory more than to habitat patchiness. The high percentage of home range size variation in the red fox explained by such a simple index of habitat richness suggests that the variety of resources (e.g. food resources, shelters) available in each territory strongly affects its size in heterogeneous environments.
Acknowledgements We are grateful to three anonymous referees for their comments. by the Maremma Natural Park Agency.
Financial support was provided
M. Luchrrini. S. Lovuri/ Behuuiourul Processes 36 (1996) 103-106
105
References Cavallini, P. and Lovari, S., 1991. Environmental factors influencing the use of habitat in the red fox, Vdpes uulpes. J. Zool., Lond., 223: 323-339. Cavallini, P. and Lovari, S., 1994. Home range, habitat selection and activity of the red fox in a Mediterranean coastal ecotone. Acta Theriol., 39: 279-287. Doncaster, C.P. and Macdonald, D.W., 1992. Optimal group size for defending heterogenous distributions of resources: a model applied to red foxes, Vulpes vulpes, in Oxford city. J. Theor. Biol., 159: 189-198. Gittleman, J.L. and Harvey, P.H., 1982. Carnivore home range size, metabolic needs and ecology. Behav. Ecol. Sociobiol., 10: 57-63. Lair, H., 1987. Estimating the location of the focal centre in red squirrel home ranges. Ecology, 64: 1092- 1101. Lovari, S., Valier, P. and Ricci-Lucchi, M., 1994. Ranging behaviour and activity of red foxes in relation to environmental variables, in a Mediterranean mixed pinewood. J. Zool., Lond., 232: 323-339. Lovari, S., Luchierini, M. and Crema, G., in press. Individual variation in diet, activity and habitat use of red foxes in a mediterranean rural area. J. Wildl. Res. Lucherini, M., Lovari, S. and Crema, G., in press. Habitat use and ranging behaviour of the red fox in a Mediterranean rural area: is shelter availability a key factor? J. Zool., Lond. Macdonald, D.W., 1981. Resource dispersion and the social organization of the red fox (Vulpes vulpes). Proc. Worldwide Furb. Conf., 1: 918-949. Macdonald, D.W., 1983. The ecology of carnivore social behaviour. Nature, 301: 379-384. Macdonald, D.W., 1987. Running with the fox. Unwin-Hyman, London, 224 pp. Meia, J.-S. and Weber, J.-M., 1993. Choice of resting sites by female foxes Vulpes uulpes in a mountainous habitat. Acta Theriol., 38: 81-91. Mohr, C.O., 1947. Table of equivalent populations of North American small mammals. Amer. Midl. Natur., 37: 223-249. Swihart, R.K. and Slade, N.A., 1985. Testing for independence of observations in animal movements. Ecology, 66: 1176-1184. Voigt, D.R., 1987. Red fox. In: M. Novak, J.A. Baker, M.E. Obbard and B. Malloch (Editors), Wild furbearer management and conservation in North America. Ministry of Natural Resources, Ontario, Canada, pp. 378-392. Voigt, D.R. and Macdonald, D.W., 1984. Variation in the spatial and social behaviour of the red fox, Vulpes vulpcs. Acta Zool. Fenn., 171: 261-265.
ELSEVIER
Behavioural Processes 36 (1996) 103-106
Short Report
Habitat richness affects home range size in the red fox Vulpes vulpes M. Lucherini, S. Lovari
*
Department of Evolutionary Biology, Ethology and Behavioural Ecology Group, University of Siena, Via Mattioli 4, 53100 Siena, Italy Accepted
17 March 1995
Abstract The spatial behaviour of the red fox Vulpes dpes shows a great flexibility (Voigt and Macdonald, 1984). Home range size varies from 10 to over 5000 ha (Macdonald, 1987; Voigt, 1987). In carnivores, variations in home range size, weighed for body mass (Gittleman and Harvey, 1982), are largely related to differences in habitat productivity, but the intraspecific local variation in home range size can be only partially explained by differences in productivity. Macdonald (1981, 1983) suggested that home range size and configuration were determined in the red fox by the dispersion of food-rich patches. More recently, it has been found that (a) where humans are intolerant to the fox, resting sites are often located peripherally in home ranges (Meia and Weber, 1993); (b) the ranging behaviour of red foxes cannot be explained only by the features of food resources in a complex environment with several productive habitats (Cavallini and Lovari, 1994); and (c) home range size may be directly related to the distance between rest sites and food patches (Lucherini et al., in press). In this paper, evidence for a strong influence of habitat richness on home range size of the red fox is reported. Keywords: Red fox; Ranging behaviour;
Habitat richness
1. Introduction In the course of an &year-long study on the red fox in a Mediterranean coastal area, 13 adult (i.e. > 1 year old) foxes were neck-snared and radio-tagged. Foxes were caught in 3 ecologically different, adjacent areas of the Maremma Natural Park (10000 ha), Central Italy: coastal ecotone (3 males, 2 females); pinewood (Pinus pinaster and P. domestica) (3 males, 1 female); rural ecotone (2 males, 2 females). Study areas, trapping and radio-tracking materials and procedures have been described in detail elsewhere (coastal ecotone: Cavallini and Lovari, 1991 and 1994; pinewood: Lovari et al.,
* Corresponding
author.
0376-6357/%/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSDI 0376-6357(95)00018-6
104
M. Luchrrini, S. Loucrri/ Brhaoiourai Procrsses 36 (1996) 103-106
0.
.
.. 1
0
.02
.04 .06
.08
.I
.12
.I4
N habitats/ha Fig. I. Exponential regression between home range size (ha) of 13 adult red foxes from three different adjacent areas and habitat richness within their respective home ranges (y = 73.52+e (‘.03- ‘O’.“); R = 0.91). Data on home ranges are from Cavallini and Lovari, 1994; Lovari et al., 1994; Lucherini et al., in press.
1994; rural ecotone: Lucherini et al., in press). All foxes were intensively radio-tracked (mean number of fixes/individual = 1067; range = 153-3 140) for 12-48 h/week/animal. In all cases, fixes were evenly distributed during the 24 h. For the aims of our study, we have not looked for statistical independence of fixes (Swihart and Slade, 19851, but for their biological independence (e.g. Lair, 1987), using a minimum time interval between successive locations (15 min) long enough to allow any radio-tagged fox to cross entirely its home range. Home range size has been estimated with the 100% minimum convex polygon (Mohr, 1947). Habitat richness has been calculated in the home range of each fox as the number of habitats/ha. Single habitats were defined in terms of salient vegetation types, e.g. vineyards vs. olive groves or pinewood. The negative correlation between home range size and habitat richness found within our rural area (Lovari et al., in press) generated the question whether this relation was limited to the local situation or could be general. Since home range size showed no significant difference between sexes (2-tailed t-test: t = 1.12; d.f. = 11; P = 0.291, data of all individuals from the 3 areas have been pooled. The negative regression between home range size and habitat richness was highly significant (P = 0.0001). An exponential model explained 83% of the variance in home range sizes (Fig. 1). Home range size of such an adaptable carnivore may be influenced by a number of variables: e.g. food patch dispersion (Macdonald, 198 1, 19831, territory defence costs (Doncaster and Macdonald, 1992), concentration of food resources (Lovari et al., 1994), rest site location (Lucherini et al., in press). In an heterogeneous environment, where each habitat provides the fox with a specific set of resources, habitat richness, as measured here, is likely related to the diversity of resources within each territory more than to habitat patchiness. The high percentage of home range size variation in the red fox explained by such a simple index of habitat richness suggests that the variety of resources (e.g. food resources, shelters) available in each territory strongly affects its size in heterogeneous environments.
Acknowledgements We are grateful to three anonymous referees for their comments. by the Maremma Natural Park Agency.
Financial support was provided
M. Luchrrini. S. Lovuri/ Behuuiourul Processes 36 (1996) 103-106
105
References Cavallini, P. and Lovari, S., 1991. Environmental factors influencing the use of habitat in the red fox, Vdpes uulpes. J. Zool., Lond., 223: 323-339. Cavallini, P. and Lovari, S., 1994. Home range, habitat selection and activity of the red fox in a Mediterranean coastal ecotone. Acta Theriol., 39: 279-287. Doncaster, C.P. and Macdonald, D.W., 1992. Optimal group size for defending heterogenous distributions of resources: a model applied to red foxes, Vulpes vulpes, in Oxford city. J. Theor. Biol., 159: 189-198. Gittleman, J.L. and Harvey, P.H., 1982. Carnivore home range size, metabolic needs and ecology. Behav. Ecol. Sociobiol., 10: 57-63. Lair, H., 1987. Estimating the location of the focal centre in red squirrel home ranges. Ecology, 64: 1092- 1101. Lovari, S., Valier, P. and Ricci-Lucchi, M., 1994. Ranging behaviour and activity of red foxes in relation to environmental variables, in a Mediterranean mixed pinewood. J. Zool., Lond., 232: 323-339. Lovari, S., Luchierini, M. and Crema, G., in press. Individual variation in diet, activity and habitat use of red foxes in a mediterranean rural area. J. Wildl. Res. Lucherini, M., Lovari, S. and Crema, G., in press. Habitat use and ranging behaviour of the red fox in a Mediterranean rural area: is shelter availability a key factor? J. Zool., Lond. Macdonald, D.W., 1981. Resource dispersion and the social organization of the red fox (Vulpes vulpes). Proc. Worldwide Furb. Conf., 1: 918-949. Macdonald, D.W., 1983. The ecology of carnivore social behaviour. Nature, 301: 379-384. Macdonald, D.W., 1987. Running with the fox. Unwin-Hyman, London, 224 pp. Meia, J.-S. and Weber, J.-M., 1993. Choice of resting sites by female foxes Vulpes uulpes in a mountainous habitat. Acta Theriol., 38: 81-91. Mohr, C.O., 1947. Table of equivalent populations of North American small mammals. Amer. Midl. Natur., 37: 223-249. Swihart, R.K. and Slade, N.A., 1985. Testing for independence of observations in animal movements. Ecology, 66: 1176-1184. Voigt, D.R., 1987. Red fox. In: M. Novak, J.A. Baker, M.E. Obbard and B. Malloch (Editors), Wild furbearer management and conservation in North America. Ministry of Natural Resources, Ontario, Canada, pp. 378-392. Voigt, D.R. and Macdonald, D.W., 1984. Variation in the spatial and social behaviour of the red fox, Vulpes vulpcs. Acta Zool. Fenn., 171: 261-265.