Executive summary

Prepared by Tricia M. Markle, Anne R. Yagi and David M. Green

Both the Allegheny Mountain Dusky Salamander (Desmognathus ochrophaeus) and the Northern Dusky Salamander (Desmognathus fuscus) are listed as endangered in Ontario under the Endangered Species Act, 2007. The Allegheny Mountain Dusky Salamander is a federally endangered species listed on Schedule 1 of the Species at Risk Act. The Northern Dusky Salamander in Ontario is yet to be assessed at the federal level.

Like all plethodontid salamanders, these species are lungless and rely on their moist skin for respiration. They are thus restricted to moist environments and avoid conditions that risk their dehydration. Both species are typically found along the edges of small woodland streams and in damp seepage areas where there is an abundance of logs, stones and leaf litter.

Dusky salamanders have a characteristic light line that runs from the corner of the mouth to the eye. The two species can best be distinguished from each other by the cross-sectional shape of the tail, the colour of the dorsal stripe and the colour of the underside. The Allegheny Mountain Dusky Salamander has a tail that is rounded in cross-section, an evident yellow- to red-coloured dorsal stripe with chevron shaped darker patches running along it, and a typically dark brown or black underside. The Northern Dusky Salamander has a keeled tail that is laterally compressed and triangular in cross-section, a uniformly tan or brown dorsal stripe, and a cream-coloured underside.

The principle limiting factor for the Allegheny Mountain Dusky Salamander and the Northern Dusky Salamander in Ontario is their extremely restricted range. In Ontario, Allegheny Mountain Dusky Salamanders have now been identified from two localities in the Niagara Gorge, while Northern Dusky Salamanders are known only from a single site. As both species occupy very similar habitats, and share many characteristics, the threats to their survival and recovery are virtually identical. The current habitat is so limited that any degradation is likely to compromise the long-term survival of these salamanders in Ontario.

The Allegheny Mountain Dusky Salamander and Northern Dusky Salamander in Ontario utterly depend upon the groundwater discharge that feeds the streams and seeps in which they dwell. Any decrease, curtailment or interruption of the groundwater is considered a serious threat to the continuing existence of these salamanders. Landslides or mudslides in the Niagara Gorge that in any way affect the salamanders' streams and stream-side habitats pose severe threats. Further, degradation of habitat may occur when hikers venture off the maintained trail and inadvertently stir up the stream bed, trample vegetation and increase erosion. Clearing of the habitats used by these salamanders would also constitute a serious threat.

The recovery goal is to safeguard the existing known populations of Allegheny Mountain Dusky and Northern Dusky Salamander species, and if feasible, introduce each species to unoccupied habitat within the Niagara Gorge that is either created or found to be suitable with the aim of increasing known population sizes by 50 percent. The four recovery objectives are to:

  • protect and enhance existing significant habitat for Allegheny Mountain Dusky Salamanders and Northern Dusky Salamanders in Ontario
  • conduct a thorough population study, and if necessary maintain the genetic health of Allegheny Mountain Dusky Salamander and Northern Dusky Salamander populations in Ontario
  • locate additional populations, and expand the current ranges of Allegheny Mountain Dusky Salamanders and Northern Dusky Salamanders through introductions where appropriate
  • elicit public support and collaboration in the protection and recovery of Allegheny Mountain Dusky Salamanders and Northern Dusky Salamanders in Ontario

The areas to be considered for habitat regulation include the streams and seeps inhabited by the salamanders, plus the surrounding forested habitat up to 75 m away from the edges of seeps and streams. In addition, the area between the two Allegheny Mountain Dusky Salamander populations should be protected as a dispersal corridor. Also to be considered are the catchment basins supplying the groundwater that feeds the springs from which the streams and seeps originate.