Evolutionary consequences of conservation havens and fenced sanctuaries

Conservation (or safe) havens are protected areas where barriers (e.g., fences) separate biodiversity from threatening processes and are being increasingly used to support conservation. Differences between selection pressures inside and outside havens can be anticipated; however, understanding of the evolutionary consequences of these differences is limited, and many changes may be going unnoticed. This hampers assessments of the extent to which haven populations will continue to represent natural populations and wild-type traits and their potential as a source of robust individuals suitable for restoration projects outside havens. Although many haven populations are essentially wild, they have similarities to ex situ conservation populations and even domestic and cultivated species that can shed light on potential changes in selection pressures and their consequences. By assessing how features of havens can alter selection pressures, one can begin to make predictions about the likelihood of genetic change and develop monitoring strategies to further inform risks that phenotypic changes in protected populations will be maladaptive outside havens. Havens could also provide opportunities as outdoor laboratories to improve understanding of selection and evolutionary processes. Research, combined with effective monitoring and adaptive management in havens, is essential to ensure the continued effectiveness of havens as a conservation tool and their ability to supply robust individuals for future in situ conservation.