Harper, M.J, McCarthy, M.A. & Van Der Ree, R. (2008). Austral Ecology, 33(3): 243-252
The authors found that processes originating from outside a remnant patch may influence ecological processes within. The study looked at the abundance of Ring-tailed and Brush-tailed Possums in Melbourne and found that food availability outside the remnant but den availability within the remnant was responsible for increasing abundance.
Abstract: There is increasing realization that human perceptions of a ‘patchy’ environment do not necessarily relate to that of a particular organism and ecological characteristics of land adjacent to patches of natural vegetation (‘remnants’) may influence the ecological processes within. We investigated how the distribution and abundance of resources within and surrounding 39 small remnants located within the city of Melbourne, Australia, influenced the abundance of common brushtail possums Trichosurus vulpecula (Phalangeridae) and common ringtail possums Pseudocheirus peregrinus (Pseudocheiridae), two primarily folivorous marsupials. Bayesian modelling techniques were used to relate the abundance of both possum species to estimates of den and food availability both within the remnant and within a 100-m buffer strip extending out into adjacent residential development. We found that both brushtail and ringtail possum abundance within remnants increased with the density of potential den sites within the remnant and food availability within the surrounding landscape. Ringtail possum density within the remnant further increased with den availability within the surrounding landscape. Our results lend support to the hypothesis that, in highly modified landscapes, processes originating outside a remnant vegetation patch may influence the abundance of species within.