Expansion of Australian reserves for fairy possums might be at expense of other species

The effectiveness of protected areas such as nature reserves in supporting a species depends on how much the species already uses, or potentially could use, the habitat. It is therefore key to assess a reserve's suitability for any given species. The authors of the present study examined the suitability of forest reserves in Victoria, Australia for conservation of the Critically Endangered Leadbeater's Possum, Gymnobelideus leadbeateri. They modelled relationships between environmental factors in the forest and where possums occurred to assign habitat suitability values, expressed as a percentage of the optimal habitat for the species, to both the current reserve system and possible expanded systems. The authors also considered how expansion of the reserve might affect three other forest-dependent species, two other marsupials and an owl species.

The researchers found that the current reserve system had a habitat suitability value of just 29.6 percent, whilst expanded systems had higher values, between 33.7 percent and 61.5 percent. However, they predicted that expansion of the current reserves to prioritize benefits for Leadbeater's possum would likely occur at the expense of other forest-dependent species, because their habitat requirements are quite different. A much larger reserve system would be needed to adequately protect all key species in this system. The study illustrates the importance of evaluating reserve expansion options in terms of trade-offs between the needs of key species.