Fire, fauna and habitat : influences on appropriate release site selection for rehabilitated wildlife

Abstract

A chronosequence approach was used to investigate the influence of fire regimes on mammal assemblages and habitat characteristics. Nineteen lowland Forest sites,last burnt between 2 and 75 years ago, via either wildfire or prescribed burning and with fire frequencies ranging from one to three fires in the previous 30 years, were sampled over a period of 3 years. The fire history variables: time since fire; type of fire and frequency of fire were explored both in combination, as a set of fire history categories, and individually, to determine how accurately they described the habitat structure and faunal assemblages at each site. The results of the study are considered in the context of identifying suitable release sites for translocated animals, such as those released following rehabilitation after injury. Such animals are regularly released into novel locations, which are usually selected by wildlife rehabilitators. The movement of wildlife to novel locations (translocation) is often associated with low survivorship. Habitat quality and the presence of conspecifics at release sites have been identified as the most influential factors affecting survival of wildlife following translocation. Accurately measuring these parameters may be beyond the scope of many wildlife rehabilitators due to limitations around capacity, experience, available time and funds. A means of simplifying the selection of high quality release sites, while reducing the need for hands on exploration of each site, was a main focus of this study. In addition to the on ground measurements, the current practices and priorities of Victorian wildlife rehabilitators relating to release of wildlife and the selection of release sites were explored via surveys. The fire history categories and the individual fire regime variables showed some relationships with faunal assemblages and with habitat composition. Habitat variables associated with arboreal fauna; such as the amount of canopy cover and tree condition were most strongly related to fire history. Swamp wallaby distributions were reasonably well described by fire frequency and severity;and other species demonstrated some spatial trends related to fire regime variables. However these variables did not provide accurate surrogate measures for habitat condition, or for the abundance or richness of fauna, across all sites. The distributions of some faunal species, such as common ringtail possum, were more accurately described by habitat structures, and did not appear to be related to fire history. Further work is needed to identify accurate, easily measured, indicators of the suitability of release sites for translocated wildlife. The wildlife rehabilitators identified habitat and the presence of conspecifics as their main priorities in selecting suitable release sites. These are also identified as important in translocation research.. A very low priority was placed on fire history. Cues to determine release readiness for hand-reared wildlife and preferences around release locations varied between respondents. Many respondents reported they release wildlife from their own properties. This practice is not aligned with operating guidelines for wildlife rehabilitators in Victoria. Although some respondents actively monitored wildlife post-release, the majority did not; therefore outcomes for released animals are largely unknown. The broad variation in release locations and techniques, as well as considerable degrees of non-compliance with wildlife rehabilitation guidelines, suggest further educational opportunities may be necessary and could improve outcomes for wildlife.