Decline of two open Champlain Sea dune systems in Eastern Ontario and their characteristic and restricted plants and insects

Abstract

Open sandy areas have existed for hundreds or thousands of years in eastern Ontario but they have declined to approximately 1 % of their former extent over the last 60-70 years. The history and decline of this unusual habitat, and its consequences for protection of biodiversity, are explored through reference to historical documents and collections as well as current surveys using two exemplary sites: Slack Road south of Ottawa and Crystal Rock in Edwardsburgh Township north of Prescott. Planting trees to eliminate these open areas, before their biodiversity value was understood, is a primary cause of the decline, but cessation of fire, invasive species and urban development have also been contributing factors. The two exemplary areas have a very similar flora and fauna and collectively contain at least five provincially rare and 65 regionally rare species, many of which are dependent on dry, open, inland sand deposits not directly associated with rivers or lakes. Based on the present rate of decline, these sandy habitats, along with their specialized flora and fauna, may be gone in a decade or two. On the other hand, the biodiversity-rich remnants could serve as nuclei for the «colonization of a restored ecosystem.