Allegheny Mountain dusky salamander COSEWIC assessment and status report: chapter 7
Habitat
Members of the genus Desmognathus are found most commonly in or near forested brooks, rills, mountain cascades, springs, or seeps, but are usually absent from large streams where predatory fish occur (Conant and Collins 1998). Boutin (2006) characterized important habitat variables associated with D. ochrophaeus. The study found that small, cool, shallow streams with intermittent water flow, deep underground water reserves, large rocks, lower water temperature, narrow stream width, and high amounts of organic matter or moss were positively associated with the presence of D. ochrophaeus. These variables were able to help detect where salamanders were present, but varied widely depending on the time of year. Desmognathus ochrophaeus occupies a broad range of habitat types and therefore co-occurs with other salamanders, both terrestrial and semi-aquatic (Tipton-Jones 1994). Within its Canadian range, D. ochrophaeus may be found within the same vicinity as the Northern Two-lined Salamander (Eurycea bislineata), the Northern Dusky Salamander (Desmognathus fuscus), the Northern Spring Salamander (Gyrinophilus porphyriticus) and the Eastern Red-backed Salamander.
Desmognathus ochrophaeus broods its eggs and overwinters in woodland springs, seeps, wet rock faces, and moist areas at higher elevations (Bishop 1941). When nesting near streams, this species typically uses sites within the banks (Organ 1961). In New York, prior to winter, these salamanders congregate, and presumably hibernate in great numbers in springs, streams, and soggy areas, not actually in the water, but along the edges beneath stones, old logs, moss and leaves, where the ground beneath is saturated (Bishop 1941; Organ 1961). During freezing periods, this species is also known to move vertically in the ground to depths of 90 cm and will stay underground just above ground water levels (Hairston 1949). During the warmer months, D. ochrophaeus can be quite terrestrial, and may often be found under logs, bark and stones in forested habitat far from water.
The ability of D. ochrophaeus larvae to survive in very intermittent seepages and streams, in which D. fuscus, E. bislineata and G. porphyriticus larvae cannot survive, must limit competition and predation by reducing the frequency of encounters. Differential use of habitat between adult D. ochrophaeus adults and larvae would also act to decrease competition within the species (Krzysik 1979). Because hydrologic conditions vary from year to year, D. ochrophaeus may be displaced in some areas by the arrival of the other species during wet years, and probably recolonizes these sites during dry years. If this is so, it would be important to conserve an area in which this species could move between several "oases" with varying hydrological regimes – this would require protection of the oases and the areas between them, or at least the important corridors (Bonin 1993).
Desmognathus ochrophaeus occurs in sites in Quebec that were cultivated in the past. The population has maintained itself despite the fact that the flow characteristics of at least some local streams have probably undergone changes resulting from the loss and subsequent regrowth of forest cover (Bonin 1993; Sharbel et al. 1995), and variation in annual rainfall (Bonin 1994). Logging in the Covey Hill area probably commenced in the 1830s, largely to clear the land for farming. Cattle had access to much of the area, even within the remaining forests. In the mid-1900s, many of these farms were abandoned, and secondary growth replaced much of the cleared area (Bonin 1994; pers. data).
The amount of water being used by homes and farms is not currently a threat to the water table. Although the existing orchards and a single campsite probably use considerable amounts of water, they are situated largely in low-lying areas rather than in the headwater areas used by the salamander. Nevertheless, a general shift is occurring in the area, from agriculture to tourism and residences: a campground was created downhill from one of the known sites, and numerous cottages have been built uphill. In 1990, a golf course was planned for the area uphill, but no decision has been made yet. Thus, although current pressure on the water table by the local human population is minimal, this could change if a large industry, residential development or golf course were erected on the hill (Barrington et al. 1993). In North Carolina, the species has been observed to use the edges of mountain roads where the rock has been dynamited and from which water oozes. Some habitats have thus been created by humans (Huheey and Brandon 1973). However, this phenomenon has not been observed in Quebec. No new habitat for this species is likely to arise outside the 100 km² potential area near Covey Hill in Quebec, as the species requires high-elevation habitats and neighbouring regions are inhospitable.
The Niagara area of Ontario has also undergone considerable development in the last couple of centuries, leaving much of the potential habitat fragmented or unsuitable. This species depends on seepage areas or streams draining from elevational heights, leaving suitable habitat restricted to the Niagara gorge and potentially the Niagara Escarpment. As there is only a single location known in Ontario, this would indicate that there is either poor dispersal between suitable habitat sites, or that this species had very specific microhabitat requirements. The stream being currently used by the Niagara population emerges from below the gorge crest. Slumping of seepage areas and landslides may have the potential to create new habitat, but also have the potential to destroy the single cascade that the Ontario population is known to use. Certain areas of habitat between the D. ochrophaeus and D. fuscus populations within the gorge are already unsuitable as the result of human development. The Niagara Escarpment is a natural fault feature stretching from Niagara Falls to Tobermory in southern Ontario. The Niagara population, however, is separated from the escarpment by the Niagara Parkway Road, and it is unknown how much of the escarpment may provide suitable habitat. Stream salamander surveys to date have not uncovered D. ochrophaeus along any section of the Niagara Escarpment in Ontario, although it is readily found along the escarpment in New York State (R. Tervo pers. comm.).
In Quebec, all the land with potential habitat for this species is under private ownership, with roughly 100 landowners involved. No steps are currently underway to acquire habitat for this species. However, the Nature Conservancy of Canada, a private conservation organization, is currently attempting to protect a natural area roughly 2 km from the nearest D. ochrophaeus site (Bonin 1993). In fact, it is work on that natural area which led to the discovery of D. ochrophaeus in Quebec. Several landowners in the area are thus already aware of the work of the Nature Conservancy of Canada. Furthermore, a presentation has been given to local citizens on the existence of the rare salamanders in the area. Habitat acquisition by itself would not guarantee protection of this species on Covey Hill. Water planning for the whole area should take into account this species' requirements, and this would have to be done in conjunction with the municipality, local residents and landowners (Bonin 1993).
In Ontario, the entire Niagara population is found in parkland that is part of the Niagara Parks system, which is managed by the Niagara Parks Commission, an agency of the Government of Ontario. The surface area where the population is found is therefore currently protected from further surface development. This does not, however, provide protection from developments in surrounding areas which may jeopardize the habitat quality and put the essential groundwater source at risk. The area is also along a very steep gorge, which makes access almost impossible from above, and very difficult from below. The location of the site decreases the likelihood of individuals disrupting the habitat.
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