Reintroduction

Successes and failures

Reintroduction biology is a relatively young discipline and continues to be a work in progress. No strict and accepted definition of reintroduction success exists, but it has been proposed that the criteria widely used to assess the conservation status of endangered taxa, such as the IUCN Red List criteria, should be used to assess reintroduction success. Successful reintroduction programs should yield viable and self-sustainable populations in the long-term. The IUCN/SSC Reintroduction Specialist Group & Environment Agency, in their 2011 Global Reintroduction Perspectives, compiled reintroduction case studies from around the world. 184 case studies were reported on a range of species which included invertebrates, fish, amphibians, reptiles, birds, mammals, and plants. Assessments from all of the studies included goals, success indicators, project summary, major difficulties faced, major lessons learned, and success of project with reasons for success or failure. A similar assessment focused solely on plants found high rates of success for rare species reintroductions. An analysis of data from the Center for Plant Conservation International Reintroduction Registry found that, for the 49 cases where data were available, 92% of the reintroduced plant populations survived two years. The Siberian tiger population has rebounded from 40 individuals in the 1940s to around 500 in 2007. The Siberian tiger population is now the largest un-fragmented tiger population in the world. Yet, a high proportion of translocations and reintroductions have not been successful in establishing viable populations. For instance, in China reintroduction of captive Giant Pandas have had mixed effects. The initial pandas released from captivity all died quickly after reintroduction. Even now that they have improved their ability to reintroduce pandas, concern remains over how well the captive-bred pandas will fare with their wild relatives.