Patterns of co-occurrence among arboreal marsupials in the forests of central Victoria, southeastern Australia

Abstract

Patterns of co-occurrence were examined among the suite of species of arboreal marsupials that inhabit the montane ash forests of the Central Highlands of Victoria, southeastern Australia. The data used in our analyses were counts of different species of arboreal marsupials derived from stagwatching surveys of 152 sites throughout the Central Highlands region. Our work investigated both the number of species that tend to occur together, as well as identity of the taxa in such associations. A total of eight different species of arboreal marsupials were recorded from field surveys of montane ash forests: Leadbeater's Possum (Gymnobelideus leadbeateri), Sugar Glider (Petaurus breviceps), Yellow-bellied Glider (Petaurus australis), Greater Glider (Petauroides volans), Mountain Brushtail Possum (Trichositrus caninus), Feathertail Glider (Acrobates pygmaeus), Common Ringtail Possum (Pseudocheirusperegrimts), and Eastern Pygmy Possum (Cercartetus nanus). Large assemblages of taxa were rare and no sites supported the full array of species of arboreal marsupialsthe maximum number of species recorded on a given 3 ha site was five. The results of our analyses indicated that if any one species of arboreal marsupials was present at a site, then on average 1.5 other taxa will co-inhabit that site. The exception was the Common Ringtail Possum. When this species was detected, few other arboreal marsupial taxa tended to be recorded with it. Principal Co-ordinates Analysis showed that although combinations of animals comprised of either Mountain Brushtail Possum, Leadbeater's Possum, or Greater Glider were often recorded, there were no strong patterns in the identities of co-occurring taxa. This finding, together with the result that most taxa in these forests typically co-occurred with one or two other species, indicates that none of the arboreal marsupials inhabiting the montane ash forests of the Central Highlands of Victoria would be a good surrogate for (or 'indicator' of), the presence of the suite of other species in the assemblage.