POST-RELEASE MONITORING
Longitudinal monitoring of health and disease has been advocated for wildlife reintroductions (Mathews et al. 2006), but has been infrequently conducted in native mammal CTs. Historically post-release monitoring in CT programs has been limited to assessment of morbidity and mortality in the immediate post-release and establishment phases of the project.
Investigation of postrelease morbidity and mortality is important because it informs decision making and allows for adaptive management strategies in subsequent phases of the project (Nichols and Armstrong 2012). An example of disease influencing post-release survival is haemorrhagic and exudative pleuropneumonia associated with the saprophytic fungus Emmonsia parva resulting in deaths of critically endangered northern hairy-nosed wombats reintroduced to establish a second free-ranging population (Schaffer-White et al. 2017). Investigation of postrelease mortality was important in this instance because the pathogen was likely present but not detected during health evaluation at the point of translocation.Several recent reintroductions have demonstrated the value of ongoing health surveillance and highlighted the potential usefulness of physiological variables in providing information on the response of individuals and the population to reintroduction beyond the traditional metrics of survival, dispersal and fecundity. Longitudinal health monitoring in a population of reintroduced eastern bettongs demonstrated changing health status of the bettongs over time, including changing ectoparasite assemblages, changes to bodyweight and changes to various haematological and biochemical parameters indicative of changing nutritional status (Portas et al. 2016). Ongoing monitoring included investigation of a mortality event several years post-reintroduction. Although a viral cause was suspected, the primary aetiological agent was not determined.
However, concurrent pulmonary cryptococcosis was identified in three individuals and represents a potentially important pathogen in the reintroduced population. Haematological variables in translocated western ring-tailed possums (Pseudocheirus occidentalis) were significantly higher pretranslocation, suggesting variations in habitat quality or nutrient intake between the source location and translocation sites (Clarke et al. 2013). Longitudinal monitoring of brush-tailed rock-wallabies identified numerous physiological changes and causes of mortality post-reintroduction (Schultz et al. 2011; Taggart et al. 2015). Additionally, evaluation of parameters associated with nutritional status suggested the diet available at the reintroduction site was adequate. Ultimately, the results of this ongoing and comprehensive monitoring allowed for the development of recommendations to improve the success of future brushtailed rock-wallaby reintroductions.Acknowledgements
I thank Larry Vogelnest and Karrie Rose for providing information on bush rat and southern brown bandicoot CTs respectively.