Monday, October 13, 2008
Salamanders of Metchosin
SALAMANDERS OF METCHOSIN
March 8, 2006
While removing broom from Devonian Park, I have several times been surprised to find a Rough-skinnned Newt partially buried in the litter. The dark brown colouring on it’s back blends in perfectly with the loamy, decaying plant material it inhabits and if it remained still, would be very difficult to find. However, my enthusiastic efforts to dislodge broom are too much for the newt as it scrambles to get out of my way. It is then that you notice the bright orange underside which warn most creatures of it’s potentially toxic secretions.
Salamanders are amphibians; creatures with thin, moist, generally smooth skin, whose eggs have a protective layer of jelly surrounding them, rather than hard shells. Many amphibians, like frogs and some salamanders, spend all or part of their lives in lakes and ponds, while some species of salamanders are fully earth-bound or terrestrial. Most aquatic species breed and lay their eggs in water, then gradually change into their adult forms (metamorphose), when they begin a life tied to forests until next breeding season.
Rough-skinned Newts are one of six species of salamanders that might be found in Metchosin. They are members of the aquatic group, breeding in water and moving onto land as adults, although some newts might remain in ponds year round. They have a grainy, bumpy skin that could led you to believe you have found a lizard, the orange belly is a dead giveaway though! Their poison is considered one of the most toxic in the world and can be passed though an open cut or through ingestion. Interestingly, our kinder, gentler, Vancouver Island newts have apparently developed without this poisonous protection.
If you notice tadpole-like creatures in your pond, you can easily tell apart salamander and frog hatchlings; salamanders are born with plumy, branched gills that noticeably fan out from the side of their bodies and remain until they change into adults, while frogs have less obvious gills that disappear soon after hatching. Salamander front legs appear before their hind ones, unlike frogs, whose hind legs develop first.
Another aquatic species is the Long-toed Salamander. It lives underground or in rotten logs, is dark gray or black with a yellow or green, somewhat broken stripe along it’s back and can grow to 9 cm (3½ inches). It seldom wanders far from water and requires abundant cover, especially vegetation along pond edges.
Northwestern Salamanders are our largest salamander and can reach 11-12 cm (4½ inches). They are generally found along the west coast but may be present in Metchosin, especially in wetter forested areas. They are uniformly brown but without the orange belly of the Rough-skinned Newt, and they have poison glands on their body which can ooze large white drops of a noxious substance. Some Northwestern Salamanders do not change into land dwellers but remain and reproduce in their gilled, aquatic state. If you find what you suspect might be this species in Metchosin, please contact firstname.lastname@example.org
All the aquatic species benefit from having undisturbed pond edges with native vegetation, so that they can access and depart from the water without being unduly subjected to predators.
The Western Red-backed Salamander, Ensatinas and Wandering Salamanders are all terrestrial salamanders. They are lungless, breathing through their skin and the lining of their mouth and they require cool, damp conditions to prevent dehydration. This helps explain why many are active at night and use rotting logs, rock rubble and underground burrows for habitat and breeding.
During construction of our home, a large sized black plastic bag that nestled into a depression was forgotten for several months. When I finally removed it to build a small rock garden, there were four Red-backed Salamanders using it for cover, the plastic keeping the site moist. The smallest wasn’t much larger than one inch and the largest about 2½ inches, the approximate size of all our terrestrial salamanders. Although their colouration has been described as variable, all the “redbacks” I’ve found have a dark colouring with a wide stripe of reddish-gold running from their necks through to the end of their tails.
Bright colours on salamanders may function as a warning, as with Rough-skinned Newts or may serve to confuse a predator, who might grab the salamander by the tail or limb, which can break off, helping the salamander to escape. Over months their lost body part will regenerate.
Ensatinas are forest dwellers that are found in the Victoria watershed and are possibly in Metchosin. The adults are usually grey or brown with a rather orange cast, particularly where the limbs meet the body, the juveniles meanwhile can be dark with metallic white or silver flecks.
Wandering Salamanders have brown to black colouring, speckled with bronze spots and splotches and are known to jump (the only salamander species here that do so). They can be found in trees, in large downed logs, under bark and in rock crevices. Our Wandering Salamanders (formerly known as Clouded Salamanders) are a source of controversy in the zoological community. Did they arrive here by hitching a ride on bark used in the tanning industry or are they a native species with widely separated populations (the next populations are in California)?
All terrestrial salamanders produce much smaller broods than aquatic species. The females expend a lot of energy guarding the eggs and appear to be able to breed only every second year. They have very limited home ranges, from one square metre to a few dozen square metres and if their home site is destroyed they will have great difficulty in populating new areas and if even possible, this process will be very slow.
Most, if not all salamander species are quite dependant on large rotting logs (over 20 inch diameter) which younger forests often can’t supply, on thick, loose bark which only occurs on mature, dying trees or on talus slopes that can be blasted and bulldozed for fill. These requirements make them extremely vulnerable to habitat loss.
When found, salamanders seem very small and fragile and you might question their value to the environment. However, salamanders play a crucial role in forest floor ecology, eating many insects and in turn, becoming prey to many larger species. If you are fortunate enough to find one, remember that their porous skin is their lungs, so it is better not to touch them and inadvertently poison them with insecticides or lotions you may have forgotten you have on your hands. If you must handle them, use gloves or place them in a leaf to view or photograph, returning them as quickly as possible to the exact spot in which they were discovered.
Amphibians of Oregon, Washington and British Columbia (1996) by Corkran and Thoms
With assistance from Kristiina Ovaska and Christian Englestoft