| Wandering salamander | |
|---|---|
| |
| Conservation status | |
 Least Concern (IUCN 3.1) | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Amphibia |
| Order: | Urodela |
| Family: | Plethodontidae |
| Subfamily: | Plethodontinae |
| Genus: | Aneides |
| Species: | A. vagrans |
| Binomial name | |
| Aneides vagrans Wake & Jackman, 1998 | |
The wandering salamander (Aneides vagrans) is species of climbing salamander in the family Plethodontidae. It has a disjunct distribution, with one population in northern California and another on Vancouver Island. It is unclear whether this distribution is natural or the result of unintentional human introductions. While it can be found terrestrially, the species is known for its habitation of the forest canopy, particularly in the crowns of coast redwood trees. When disturbed, individuals of this species may leap from trees, utilizing physiologic adaptations to glide and control their descent in the air.
Description
The wandering salamander is a long, slender salamander that grows to a snout-vent length of 3 inches (76 mm) and a total length of 5 inches (130 mm). Its base color ranges from brown to light grey, with lighter bronze-grey mottling distributed across its dorsal surface. Juveniles also have a coppery-bronze stripe down the spine. The species has between 14-16 costal grooves, though 15 is most common. The head is broader in males than in females. Between the nostrils and the mouth are a pair of naso-labial grooves that are involved in chemoreception.
The species has adaptions conducive to an arboreal lifestyle, with relatively long legs and toes that have expanded terminal pads with square cut ends. The tail is prehensile, round in cross section, and used to help the salamander clamber around branches of trees.
The wandering salamander is similar in appearance to the clouded salamander (Aneides ferreus) and they were at one time considered to be the same species.
Taxonomy
The wandering salamander and the clouded salamander were considered the same species until 1998. Prior to splitting, the clouded salamander's range extended from northern California to Oregon, with an adjunct population on Vancouver Island. However, an examination of the mitochondrial DNA and allozymes of populations from various parts of the species' range determined that individuals from California and Vancouver Island were genetically similar to one another and distinct from the populations found in Oregon. The species found in California and Vancouver Island was subsequently dubbed Aneides vagrans, the wandering salamander, while the species found in Oregon retained the name Aneides ferreus.
Distribution
In California, the wandering salamander's range extends from from northern Siskiyou and Del Norte Counties, south along the coast through northwestern Sonoma County. The species is widespread across Vancouver Island and surrounding islands. The cause of the disjunct distribution of A. vagrans is disputed.
It has been postulated that A. vagrans was introduced to Vancouver Island during the nineteenth century as the result of the import of large sheets of tanoak bark from California for the tanning industry, and subsequently spread to nearly all the small offshore islets around Vancouver Island, probably on rafts of logs. However, many of the first detections of this species on Vancouver Island were made well before logging roads for transporting tanoak wood would have been developed.
It is also possible that the disjunct distribution of A. vagrans has a natural cause. A. vagrans individuals from the California populations may have rafted to Vancouver Island during the Holocene via logs carried on the Davidson Current. Alternatively, both A. vagrans populations may have once been part of a single population distributed across the West Coast that became fragmented by glaciation, with populations surviving in refugia in both California and Vancouver Island. However, population fragmentation typically leads to genetic divergence over time, which would make the very close genetic similarity between California and Vancouver populations somewhat surprising.
Habitat
The species occurs from sea level to 1,700 metres (5,600 ft).
Adult salamanders can be found in the forest canopy, or moist terrestrial habitats such as rotting logs, bark crevices, stumps, and the underside of rocks. Individuals may climb up to 80 ft (24 m) in the branches of trees, and have been found living in the crowns of coast redwoods. Although research on arboreal microhabitat selection in this species has been minimal, they appear to associate with epiphytic fern mats in the crotches of redwood branches.
Life History
Reproduction
Breeding takes place in spring and early summer. The female lays a clutch of six to nine eggs in some concealed location such as under bark. She guards them as they develop and they eventually hatch directly into miniature adult salamanders with no aquatic larval stage.
Inactivity
In California it may aestivate in summer and be active in winter while in Vancouver Island it may be active in summer and hibernate in winter.
Diet
This species feeds at night on small invertebrates such as ants, mites, adult beetles and their larvae, snails, springtails and woodlice.
Gliding Behavior
Wandering salamanders may leap from trees when disturbed, and have several adaptations that allow them to manipulate their descent. Wind tunnel experiments have found that wandering salamanders can control their pitch, roll, and yaw when in the air such that their body remains upright and stable in a "skydiving" posture that reduces descent speed. This posture generally involves spread legs and splayed feet, with the tail angled upwards. The large feet and long toes of this species appear to help reduce drag when in the air, contributing to reduced speed. The long legs of this species also position the feet far from the body, which may aid in aerial maneuvering. Parasagittal undulations of the tail and torso allow wandering salamanders to glide in a controlled manner similar to arboreal squamates. This enables them to land on the trunk of a tree — often the same tree that they jumped from — instead of falling all the way to the ground.
Status
The wandering salamander is listed as Least concern in the IUCN Red List of Threatened Species, though populations are declining. Habitat loss due to intensive, short-rotation logging practices and land clearing for agriculture and residential development is believed to be the primary cause of population declines. In addition to removing trees in which the salamanders may live, over the long term logging also reduces the availability of coarse woody debris on the ground, which the salamanders use as habitat and for egg-laying. It is thought that salamanders may thrive initially after logging, but decline as remaining logs and stumps decay and are not replaced. However, logging in British Columbia does not appear to affect wandering salamander populations, and the species can persist in regenerating forests.
Climate change is likely a threat to this species due to drought and habitat shifts in the coastal Douglas-fir biogeoclimatic zone in which the salamanders dwell. The emerging Batrachochytrium salamandrivorans fungus also has the potential to affect wandering salamander populations, though it has not yet been confirmed to be present in North America.
References
- ^ IUCN SSC Amphibian Specialist Group (2022). "Aneides vagrans". IUCN Red List of Threatened Species. 2022: e.T59119A197437244. Retrieved 17 December 2022.
- ^ Jackman, T. R. (1998). "Molecular and historical evidence for the introduction of clouded salamanders (genus Aneides) to Vancouver Island, British Columbia, Canada, from California" (PDF). Canadian Journal of Zoology. 76 (8): 1570–1580. doi:10.1139/z98-091.
- ^ body., Committee on the Status of Endangered Wildlife in Canada, issuing (2014). COSEWIC assessment and status report on the wandering salamander, Aneides vagrans, in Canada. Canadian Wildlife Service = Service canadien de la faune. ISBN 978-1-100-23928-6. OCLC 923013075.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ "Aneides vagrans - Wandering Salamander". CaliforniaHerps. Retrieved 2012-08-31.
- Wake, David B. "Aneides vagrans". AmphibiaWeb. Retrieved 2012-08-31.
- ^ Brown, Christian E.; Sathe, Erik A.; Dudley, Robert; Deban, Stephen M. (2022-05-23). "Gliding and parachuting by arboreal salamanders". Current Biology. 32 (10): 453–454. doi:10.1016/j.cub.2022.04.033. PMID 35609538.