Orientation to forested patches: perceptual range of the red-bellied tree squirrel (Callosciurus erythraeus) introduced in Argentina

BRIDGMAN, L.; BENITEZ, V.V.; GRAÑA GRILLI, M.; MUFATO, N.; ACOSTA, D.; GUICHÓN, M.L.

Torquay Victoria

Congreso; 23rd Australasian Wildlife Management Society Annual Conference; 2010

Dispersal success of individuals is an important determinant of population level distribution. For introduced species, it is a key element of the invasion process. In a heterogeneous landscape, dispersal is influenced by perceptual range, which is the distance from which an animal can perceive habitat and orientate toward it. Investigating perceptual range could improve understanding of colonisation and management of introduced species. We tested the perceptual range of the red-bellied tree squirrel (Callosciurus erythraeus), introduced to Argentina in the 1970s. Animals were trapped, transported to agricultural land and released at four distances from a forest patch. Orientation of movement paths relative to forest were analysed. Based on previous literature we predicted that squirrels would perceive forest at 100m, may perceive forest at 200m and would be unsuccessful at 300m. Releases at 20m were carried out to test the validity of the method. Movement paths of squirrels showed significant orientation toward forest at 20m, but not greater distances, indicating a perceptual range below 100m. We compare our findings to those of other small mammal studies. Low evolutionary history in open areas is a possible explanation for the relatively short perceptual range of the red-bellied tree squirrel. Implications for management are discussed.