Wildlife health outcomes and opportunities in conservation translocations

1. It is intuitive that the health status of wildlife might influence conservation translocation outcomes, however health as a topic has received limited attention in the conservation translocation literature. We aimed to determine the forms and frequency of ill-health reported in translocated animals and plants, and in populations linked to translocation, and associations between ill-health and translocation ‘success’. We also explored the relationships between health, other biological problems and processes, and management measures.
2. Using described selection criteria, a subset of case studies of animal and plant conservation translocation from the IUCN’s ‘Global Reintroduction Perspectives’ series (2008-2018) was reviewed. Self-reported information describing or implying mortality, ill-health or reproductive compromise was extracted and categorised as a ‘disease’ or other biological problem. Problems explicitly described as a ‘major difficulty’, ‘major lesson’ or ‘reason for failure’ were termed ‘notable’. We specified the conditions representing ill-health and created diagrams providing a contextual framework to health and its management.
3. Notable ‘disease’ problems such as infection, stress and husbandry-related disorders were reported in 30% (n = 89) of 295 reviewed case studies and were more likely to be mentioned in less ‘successful’ projects (P < 0.05, χ2 test). Other biological problems, in particular predation, adverse climate or weather, and anthropogenic trauma, were commonly reported (66% of 295 studies), especially post-release.
4. When present, disease may be an important obstacle to translocation success. The negative impacts of other, apparently common post-release problems on health also merit acknowledgement. A broad spectrum of ill-health conditions can potentially occur through conservation translocations, and are important from both conservation and animal welfare perspectives. We suggest health management of translocation has three broad roles: to mitigate disease risks posed to other animals, plants or humans; to mitigate threats to the health of translocated individuals themselves; and to preserve and build the resilience and adaptive capacity of translocated individuals, given the apparent high frequency of post-release threats. We advocate a stronger emphasis on fostering health as opposed to solely preventing disease. This is directly and indirectly dependent on a wide range of related project management actions and on multi-disciplinary expertise.