This is why I can’t blog and update a lot… I’m busy doing things like this… Gah.
Bio 212, Winter Quarter
Figure 1: Coastal Giant Salamander (Dicamptodon tenebrosus) (Nafis)
Dicamptodon tenebrosus, the Coastal Giant Salamander, has its habitat in fast-flowing clear streams and forest floors (within ~50 meters of those streams), and rarely comes in contact with human beings, avoiding heavily populated settlements (California). Given that information, one might assume that they would be subject to heavy habitat loss through logging, siltation of their steams, and other human activities. The reality is a bit murkier.
The Canadian government, through its environmental arm, the Ministry of Environment, Lands, and Parks, has placed tenebrosus on its provincial red list (candidates for threatened or endangered status), because inside of the borders of Canada, the area in which tenebrosus is found is quite small, and may be threatened by just such behavior as was discussed before – logging and siltation of streams reducing the available habitat (Blood).
However, the IUCN red list has them listed as ‘Least Concern’, citing ” wide distribution, presumed large population,” and that “it [tenebrosus] is unlikely to be declining fast enough to qualify for listing in a more threatened category.” (Hammerson). The wide distribution the IUCN cites stretches over 700 miles linear, from northwestern California to the Chilliwack drainage in B.C., Canada. This does not include breadth of distribution, which may be wide or narrow, depending on local area conditions.
The IUCN is not alone in their designation. The Washington Herp Atlas cites state and Global (US) conservation statuses of S5 (“Demonstrably widespread, abundant, and secure in the state; believed to be ineradicable under present conditions”) and G5 (“Demonstrably widespread, abundant, and secure globally, though it may be quite rare in parts of its range, especially at the periphery”), respectively (Hallock).
Does this mean there is no cause for concern? The answer seems to be both yes and no. While tenebrosus is in no immediate danger, future habitat losses due to unsafe logging practices, coupled with predation and the difficulty in doing species-count studies with a species so adept at hiding from exposure, raises the possibility of not knowing enough about population losses until they reach a critical mass.
In closing, while they only seem to be rare at the periphery of/outside of their natural habitat, these animals live in a habitat directly impacted by logging and other human industry. Safe logging and forest habitat preservation practices will go a long way toward making sure tenebrosus never gets endangered, keeping these wonderful animals around for future generations.
- California Herps, http://www.californiaherps.com/salamanders/pages/d.tenebrosus.html (Acessed Mar. 1, 2013)
- Blood, Donald A., et. al, Pacific Giant Salamander (brochure) http://www.elp.gov.bc.ca/wld/documents/salamander.pdf (accessed Mar. 1, 2013)
- Hallock, L.A. and McAllister, K.R. 2009. Pacific Giant Salamander. Washington Herp Atlas. http://www1.dnr.wa.gov/nhp/refdesk/herp/ Downloaded on 15 January 2013
- Hammerson, Geoffrey, 2004. Dicamptodon tenebrosus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2 http://www.iucnredlist.org/details/59081/0. Downloaded on 15 January 2013.
- Image : Nafis, Gary, http://www.californiaherps.com/salamanders/pages/d.tenebrosus.html (Accessed: Mar. 1, 2013)