Biodiversity in Ontario's Greenbelt (PDF) - David Suzuki Foundation

What are Species
At Risk Telling Us
The loss or decline of species is often used to illustrate loss of function in ecosystems. Like the
canary in the coal mine once used to determine whether the levels of poisonous gas were too
high for humans, these species signal the impact of human activities in the environment on which
humans also ultimately depend. Four species at risk are highlighted here to illustrate the range of
threats faced by species occupying diverse habitats across the Greenbelt and to demonstrate the
pervasive challenge posed by ongoing habitat loss and degradation.
In the five years following the creation of the Greenbelt in 2005, 22 new species were listed as
being at risk in Ontario. Eight of these species, roughly one-third, have habitat in the Greenbelt: rapids
clubtail, common snapping turtle, bobolink, Canada warbler, chimney swift, common nighthawk,
olive-sided flycatcher and eastern flowering dogwood. Threats to these species are diverse, and in
some cases, such as the aerial insectivores, poorly understood. 79 Invasive species, pesticide use,
road mortality, hunting, agricultural operations and less prey are among the causes of decline for
one or more of these species. Habitat loss and degradation are a common threat to all. 80
Four Greenbelt species have been placed in higher-risk categories. Three of these species — American
columbo, redside dace and spotted turtle — face habitat loss as a primary threat. One species,
American chestnut, is threatened by the non-native chestnut blight fungus. 81
Redside dace: The health of the watershed
For the redside dace,
of which 80 per cent of
the remaining population
occurs in the Greenbelt,
habitat loss and degradation
resulting from urbanization
are the greatest threats.
For the redside dace, of which 80 per cent of the remaining population occurs in the Greenbelt,
habitat loss and degradation resulting from urbanization are the greatest threats. 82
The redside dace has been steadily declining over time. Five of 24 confirmed historic populations
have already been lost. 83 Although its greatest stronghold in Ontario lies within the Greenbelt, it
continues to decline even here — a sign of the deterioration of hydrological systems within the
plan area caused by development pressures. Alarmingly, some of its most stable populations are
in Greenbelt municipalities expected to face significant jumps in human population in the next 10
to 15 years: Durham, York and Simcoe. 84
79 J. McCracken. 2008. Are aerial insectivores being “bugged out” BirdWatch Canada 42: 4–7.
80 COSEWIC.
81 See American chestnut at www.cosewic.gc.ca.
82 Redside Dace Recovery Team. 2010. Recovery Strategy for the Redside Dace (Clinostamus elongatus)
in Ontario. Ontario Recovery Strategy Series. Prepared for the Ontario Ministry of Natural Resources.
Peterborough, Ontario. pp.6–10.
83 Redside Dace Recovery Team, Recovery Strategy, pp.6–10.
84 COSEWIC. 2007. COSEWIC Assessment and Update Status Report on the Redside Dace (Clinostomus elongatus)
in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa, Canada. p.28.
Page 22
Biodiversity in Ontario’s greenbelt