Sustainability Index (S-Index): A tool for use in the evaluation and planning of institutional animal collections.

Maintaining sustainable living collections is at the core of every zoo's and aquarium's mission. In spite of increasing awareness of sustainability challenges, few practical applications to support collection sustainability have been developed. In addition, much of the onus to address issues regarding collection sustainability has fallen to regional zoo associations, rather than on individual collection managers, creating a "tragedy of the commons." Responsibility for sustainability, however, ultimately defaults to each individual institution; as active participants in an association and the population management system, other institutions are the most reliable source of animals. Each collection manager must ensure that their collection contributes to association-wide sustainability. With this in mind, a sustainability index tool, S-Index, has been developed using basic demographic concepts and novel metrics for institutional collection evaluation. Furthermore, combining S-Index data across facilities allows the evaluation of the sustainability of individual taxa or taxonomic groups within the Association. An S-Index analysis of 27 Association of Zoos and Aquariums member avian collections over ten years demonstrates the use of this analytical tool.