Directions in reintroduction biology.

Reintroductions are attempts to return species to parts of their historical ranges where they were extirpated, and might involve release of either captive-bred or wild-caught individuals. The poor success rate of reintroductions worldwide has led to frequent calls for greater monitoring, and since 1990 there has been an exponential increase in the number of peer-reviewed publications related to reintroduction. However, these publications have largely been descriptive accounts or have addressed questions retrospectively based on the available data. Here, we advocate a more strategic approach where research and monitoring targets questions that are identified a priori. We propose ten key questions for reintroduction biology, with different questions focusing at the population, metapopulation and ecosystem level. We explain the conceptual framework behind each question, provide suggestions for the best methods to address them, and identify links with the related disciplines of restoration ecology and invasion biology. We conclude by showing how the framework of questions can be used to encourage a more integrated approach to reintroduction biology.