Why You Can’t Ignore Disease When You Reintroduce Animals

Product Type: 

Book, Pages in

Year: 

2016

Author(s): 

Muths, E.L. and H. McCallum

Suggested Citation: 

Muths, E.L. and H. McCallum. 2016. Why You Can’t Ignore Disease When You Reintroduce Animals. In: Reintroduction of Fish and Wildlife Populations. (David S. Jachowski, Ed.) University of California Press.

Infectious disease is an important consideration when contemplating reintroduction of a species to an area from which it has been extirpated and is one risk that has escalated in recent decades as use of large-scale and hands-on conservation measures increase. Reintroduction (in essence moving animals around), is a management tool considered when populations are failing or extirpations have occurred, yet is obviously at odds with many of the tenets of disease management. We focus on extirpations attributed to disease and formulate a decision tree to guide managers considering reintroduction. If disease was not the original cause of extinction or decline, it still is important to consider as inadvertent introduction of disease with reintroduced hosts may cause a reintroduction to fail, or may threaten members of the recipient ecological community. If disease was an important agent of extinction or decline, then the disease threat must be addressed before reintroduction is contemplated, or the effort is highly likely to fail. If disease resistant or tolerant stock are available, then reintroducing these animals may succeed. If such stock are not available, then it is important to determine whether reservoirs are present, and if they are, to develop strategies to manage disease adequately in the reservoirs. If reservoirs are not present, then the biggest threat to a reintroduction is the presence of still-infected members of the species being reintroduced. We illustrate these principles with two case studies, the boreal toad (Anaxyrus (Bufo) boreas), threatened by the amphibian chytrid fungus (Batrachochytrium dendrobatidis) and the Tasmanian devil (Sarcophilus hariisii), threatened by a transmissible cancer.