An introduction to using mark-recapture analysis for monitoring threatened species

Accurate and reliable monitoring is necessary for effective management of threatened species in New Zealand. Mark-recapture studies are a powerful tool for conservation managers, and can be used in any situation where animals can be marked (or otherwise identified) and detected later by capture or sighting. In addition to estimating population size and survival rates, mark-recapture methods can be used to evaluate impacts of threats on survival, record population trends, collect information for population viability analyses, set performance targets against which responses to management can be measured, and highlight areas where further research is necessary. This report has three main sections. The first section introduces the basic principles of markrecapture methodology that conservation managers need to understand to design effective mark-recapture studies. In the second section, specific guidelines for estimating abundance, survival and population growth rates are provided. We show which methods are appropriate for different situations, how field studies should be designed to avoid violating assumptions of markrecapture methods, and how to get started on analysing the data. In the final section, we review a case study involving long-tailed bats (Chalinolobus tuberculatus), and use this to illustrate some problems that may be encountered in mark-recapture studies.