Empirical evaluation of the strength of interspecific competition in shaping small mammal communities in fragmented landscapes
- 433 Downloads
Theory predicts that habitat loss and fragmentation may have drastic consequences on species’ interactions. To date, however, little empirical evidence exists on the strength of interspecific competition in shaping animal communities in fragmented landscapes.
Our aim was to measure the degree of ongoing competitive interference between species in fragmented landscapes. Our model system was the community of ground-dwelling rodents in deciduous woodlands in central Italy, composed of a habitat generalist species (Apodemus sylvaticus) and two forest specialists (Apodemus flavicollis and Myodes glareolus). Our objectives were to test whether species were segregated among forest patches and whether spatial segregation was determined by interspecific competition or habitat and resource availability.
We surveyed the populations inhabiting 29 woodland patches in a highly fragmented landscape using a capture-mark-recapture protocol, capturing >4500 individuals. First we modelled species’ distribution as a function of habitat, resource availability and landscape variables. The second stage of our analyses involved measuring the response of vital rate parameters (body mass, reproduction, survival, recruitment, population density) to competitor density.
The relative distribution of species reflected a spatial segregation of habitat generalists and specialists according to habitat quality, cover and connectivity. Interspecific competition mainly affected individual level vital rates, whereas we found no substantial effects at the population level.
Competitive exclusion of specialist species by generalist species was occurring. However, when compared to other factors such as habitat connectivity and resource availability, interspecific competition played a relatively minor role in shaping the studied community.
KeywordsAgricultural matrix Hedgerows Landscape mosaic Oak forest Patch size Rodents
Two anonymous reviewers provided valuable and constructive feedback on our manuscript. We thank all students that helped us with fieldwork. Molecular analyses for the discrimination of Apodemus spp. were carried out by GS, Simona Prete and Emanuela Solano. We also thank Ben Scheele, Jennnifer Pierson e Ayesha Tulloch (The Australian National University) and Marilena Ronzan for language revision. GS was funded by a Ph.D. grant awarded by the University of Rome “La Sapienza”, AM was funded by the CFS (Corpo Forestale dello Stato) through the University of Rome “La Sapienza”.
- Amori G, Contoli L, Nappi A (2008) Fauna d’Italia: Mammalia II. Edizioni Calderini de Il Sole 24 ORE Edagricole, BolognaGoogle Scholar
- Amstrup S, McDonald L, Manly B (2006) Handbook of capture-recapture analysis. Princeton University Press, Princeton, NJGoogle Scholar
- Buchalczyk T, Olszewski JL (1971) Behavioural response of forest rodents against trap and bait. Acta Theriol 16:233–239Google Scholar
- Burnham KP, Anderson DR (2002) Model selection and multimodel inference: a practical information-theoretic approach, 2nd edn. Springer, New YorkGoogle Scholar
- Capizzi D, Luiselli L (1996) Ecological relationships between small mammals and age of coppice in an oak-mixed forest in central Italy. Rev Eco (Terre Vie) 51:277–291Google Scholar
- Cihakova J, Frynta D (1996) Intraspecific and interspecific behavioural interactions in the wood mouse (Apodemus sylvaticus) and the yellow-necked mouse (Apodemus flavicollis) in a neutral cage. Folia Zool 45:105–113Google Scholar
- Fairley JS (1982) Short-term effects of ringing and toe-clipping on the recapture of wood mice (Apodemus sylvaticus). J Zool 197:295–297Google Scholar
- Gębczyńska Z (1983) Feeding habits. In: Petrusewicz K (ed) Ecology of the bank vole. Acta Theriologica XXVIII (Supplement No. 1), pp 40–49Google Scholar
- Harris S, Yalden D (2008) Mammals of the British Isles: handbook. The Mammal Society, SouthamptonGoogle Scholar
- Hoffmeyer I, Hansson L (1974) Variability in numbers and distribution of Apodemus flavicollis (Melch.) and A. sylvaticus (L.) in South Sweden. Z für Säugetierkd 39:15–23Google Scholar
- Lindenmayer DB, Fischer J (2006) Habitat fragmentation and landscape change. An ecological and conservation synthesis. Island Press, Washington, DCGoogle Scholar
- Margaletic J (2004) Glavas M (2002) The development of mice and voles in an oak forest with a surplus of acorns. J Pest Sci 75:95–98Google Scholar
- Mortelliti A, Amori G, Annesi F, Boitani L (2009) Testing for the relative contribution of patch neighborhood, patch internal structure, and presence of predators and competitor species in determining distribution patterns of rodents in a fragmented landscape. Can J Zool 87:662–670CrossRefGoogle Scholar
- Nupp TE, Swihart RK (2001) Assessing rodents competition between forest rodents in a fragmented landscape of midwestern USA. Mamm Biol 66:345–356Google Scholar
- R Core Team (2013) R: a language and environment for statistical computing, Ver.3.0.2Google Scholar
- Ripperger SP, Tschapka M, Kalko EKV, Rodríguez-Herrera B, Mayer F (2014) Resisting habitat fragmentation: high genetic connectivity among populations of the frugivorous bat Carollia castanea in an agricultural landscape. Agric Ecosyst Environ 185:9–15. doi: 10.1016/j.agee.2013.12.006 CrossRefGoogle Scholar
- Schradin C, Pillay N (2005) Demography of the striped mouse (Rhabdomys pumilio) in the succulent karoo. Mamm Biol 70:84–92Google Scholar
- Stanley TR, Richards JD (2004) CloseTest: a program for testing capture-recapture data for closure, Ver. 3Google Scholar