White wood aster (Eurybia divaricata) COSEWIC assessment and status report: chapter 8

LIMITING FACTORS AND THREATS

No species-specific factors limit the distribution of Eurybia divaricata.  Habitat destruction is the greatest threat to the species in both provinces.

The weevil Barypeithes pellucidus, which occurs in Ontario, preferentially consumes Eurybia divaricata in central Ohio (Galford 1987).  Elsewhere in its range Eurybia divaricata is preferentially browsed by white-tailed deer in Pennsylvania and has been suggested as a potential indicator species for browsing intensity (Williams et al., 2000). Given the high deer populations in southern Ontario, this is certainly a potential threat.

Ontario

The populations at Niagara Shores Conservation Area are located perilously close to a well-used trail system and an actively eroding sand dune.  One site at Short Hills Provincial Park is situated near high-use hiking trails.  The populations at Four Mile Creek and at Short Hills may be threatened by the non-native garlic mustard (Alliaria petiolata) which is abundant throughout these two wooded areas. Some plants at Short Hills also appeared to have been grazed by deer. The Marcy’s Woods, Short Hills and the St. John Conservation Area populations are impacted by trails running through the middle of the colonies.  Culp’s Woods may be in danger as well, as the remainder of the woodlot could be cleared for orchard expansion.  South Fort Erie has been slated for development into a subdivision.  Crescent Estates Woodlot population has been harvested or partially excavated.

Quebec

No site-specific threats are listed for any of the populations in Quebec, yet it is generally inferred in the site descriptions that habitat loss through development (golf course, landfill) and woodlot thinning are affecting the populations.

Page details

Date modified: