The influence of feral horses on the ecology of Sable Island National Park Reserve

Coastal ecosystems worldwide suffer habitat loss and degradation from human activities. Island ecosystems are especially sensitive, with specific threats to endemic biodiversity from introduced species. Sable Island National Park Reserve, a sand dune off the coast of Nova Scotia, has several endangered endemic species. Management of the sensitive ecosystems of Sable Island requires knowledge of how the wild horse population, introduced before the 18th century, will impact these systems as populations grow. Extensive grazing and trampling of sensitive habitat has degraded the freshwater ponds that sustain many species, and exacerbated the loss of heath habitat used by migrating bird. In collaboration with Parks Canada, the Geologic Survey of Canada, Dalhousie University, Saint Mary's University, and the Sable Island Institute have set up an experiment where large (0.5-1.3 ha) exclosures have been deployed across Sable Island to test how horses affect coastal dune communities. We expect that the exclosure experiment will allow for natural regeneration of heath habitat, stabilization of dunes, and improvement to water quality of the freshwater ponds within the enclosed areas. By comparing the ecology of enclosed areas to other ecosystems that the horses use, we hope to help inform effective management of the population such that impacts to fragile dune ecosystems can be minimized. Drawing on the Geological Survey of Canada's collaboration on coastal zone management, combined with the Sable Island Institute's dedication to public engagement, this project also aims to share findings regionally, nationally, and internationally through public outreach, peer-reviewed publications, and media to shed light on the role introduced large herbivores may have on native and non-native species, and coastal resilience.