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Desmognathus fuscus was previously considered to be made up of three subspecies: northern dusky salamanders (D. f. fuscus), spotted dusky salamanders (D. f. conanti), and Santeetlah dusky salamanders (D.f. santeetlah). However, most authorities now consider these three to be separate species: D. fuscus, D. conanti, and D. santeetlah. The range of northern dusky salamanders is as described above. Spotted dusky salamanders range from southern Illinois and western Kentucky south to the Gulf Coast. Santeetlah dusky salamanders occur only in a small geographical area high in the Unicoi, Great Smoky, and Great Balsam mountains of North Carolina and Tennessee.

The three traditional subspecies are very similar in physical appearance, with only subtle differences. D. f. santeetlah is usually the smallest and darkest. D. f. conanti is usually the most colorful, and often has 6 to 8 pairs of gold or red spots (or single lateral lines) along the back. The pattern on D. f. conanti likely comes from the juvenile character (present in all subspecies) of a wavy band and yellowish or reddish spots along the back. Desmognathus f. fuscus varies from brown or reddish brown to gray or olive, with slightly darker markings on the top and sides. The base of the tail is typically olive, yellow, or bright chestnut (a bit lighter than the body). The belly is whitish with some dark speckles (in D. f. fuscus) or lighter speckles (in D. f. conanti). The belly of D.f. santeetlah is yellowish with dark speckles. Usually there is a light stripe from the eye to the back of the mouth.

Hybridization sometimes occurs between D. fuscus and a close relative, mountain dusky salamanders (Desmognathus ochrophaeus) in Pennsylvania and Ohio. Extensive interbreeding occurs between D. fuscus and D. santeetlah where their ranges overlap in the northwestern Great Smoky Mountains.

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Hannah Edwards, Michigan State University
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Behavior

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It is thought that the nasolabial groove (characteristic of members of the family Plethodontidae) aids in smelling prey items as well as potential mates. Chemical odors may be transported along the groove and into the mouth, where the vomeronasal organ can transfer the information to the salamander's brain. Also, glands (like the mental gland, located on the chin) are used to communicate with mates when courting. The male will vigorously rub his chin onto the female, as well as bite her, in order to provide her with pheromone secretions until she becomes fully receptive. If a brooding female is returning to her nest after feeding at night, she can recognize which clutch is hers by using chemical cues. Dusky salamanders may bite a threatening predator. Also, a male may attack a another male that is courting a female.

Communication Channels: tactile ; chemical

Other Communication Modes: pheromones ; scent marks

Perception Channels: tactile ; chemical

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Hannah Edwards, Michigan State University
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Conservation Status

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Dusky salamanders can be common where habitat is intact and abundant in areas such as shaded streamsides in moist woods. But they are threatened in some areas by tree removal, which exposes the area to sun, increasing the water temperature and decreasing the humidity. Pollution of waterways can also be a serious threat. The overall effects of bait collection are unknown, but this activity may certainly impact local populations, especially if collection techniques (such as rock turning) disrupt the local habitat.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Hannah Edwards, Michigan State University
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Life Cycle

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Upon hatching, dusky salamander larvae are about 1.6 cm (0.6 in) long and have well-developed limbs. The larvae may stay with their mother for several days or even weeks before going to the water. Because they are aquatic, they have gills, which are small and white. However they can survive in moist terrestrial environments for some time if required, and terrestrial metamorphosis may be possible. After spending 7 to 11 months in the water they undergo metamorphosis (in the spring or summer after hatching). Newly transformed salamanders are 2.8 to 4.4 cm (1.1 to 1.7 in.) long.

Development - Life Cycle: metamorphosis

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Benefits

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There are no known adverse effects of Desmognathus fuscus on humans.

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Benefits

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In the southeastern United States, salamanders in the genera Desmognathus, Gyrinophilus, and Pseudotriton are collected and sold as fishing bait for largemouth bass (Micropterus salmoides) and other sport fish. In bait shops, you can find them labeled as "spring salamanders" or, as often, "spring lizards." The lungless (plethodontid) salamanders (including Desmognathus) are important in nutrient cycles in the forest ecosystem, which undoubtedly helps maintain the health of forest resources.

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Associations

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Dusky salamanders are second and third order consumers that eat a wide variety of small terrestrial and aquatic invertebrates. They are opportunists and will eat whatever is available in high abundance. Dusky salamanders are prey to a number of animal species representing many vertebrate (and perhaps some invertebrate) groups, including mammals, snakes, birds, and larger amphibians. Desmognathus fuscus often shares its habitat with other species of the genus Desmognathus, and other plethodontid salamanders. It appears that niche partitioning occurs, and animals of the different Desmognathus species have a broader habitat preference in areas of overlap than in areas that the species do not overlap. Other species that have been found to coexist with D. fuscus are seal salamanders (D. monticola), Allegheny Mountain dusky salamanders (D. ochrophaeus), southern dusky salamanders (D. auriculatus), and northern two-lined salamanders (Eurycea bislineata).

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Hannah Edwards, Michigan State University
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Trophic Strategy

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Dusky salamanders are carnivorous, and eat small invertebrates (both terrestrial and aquatic) including earthworms, slugs, snails, crustaceans, spiders, mites, flies and fly larvae, ants, beetles and beetle larvae, centipedes, moths, and mayflies. Dusky salamander larvae eat crustaceans, insect larvae, copepods, and mites. The diet is fairly nonspecific, and they tend to eat whatever is in abundance. Dusky salamander larvae or small juveniles are occasionally eaten by large adults.

Animal Foods: insects; terrestrial non-insect arthropods; mollusks; terrestrial worms

Primary Diet: carnivore (Insectivore , Eats non-insect arthropods, Molluscivore , Vermivore)

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Distribution

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Northern dusky salamanders occur from southern New Brunswick and Quebec, along the East Coast to North Carolina, and west to Ohio, southern Indiana, Kentucky, and Tennessee. Over most of their range, dusky salamanders are common in appropriate habitat. Their distribution in the southern Appalachian Mountains is sporadic. Desmognathus fuscus recently included three subspecies, which continued the range to the Gulf Coast. Most authorities now consider these to be separate species. See "Other Comments" below for further information. A breeding population of Desmognathus fuscus has been found at one site in eastern Michigan; whether this population is introduced or a natural relict has not yet been determined.

Biogeographic Regions: nearctic (Native )

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Habitat

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Northern dusky salamanders prefer wooded or partially wooded moist habitats with running or trickling sources of water. Most often, they are found under flat rocks or logs near rocky or hillside streams or seeps, or in the moist, misty habitat near waterfalls. They may go into the water to find cover under rocks or substrate if disturbed. If the stream substrate does not freeze, they can remain active year-round. In extremely cold conditions, they will burrow under gravel until they are below the frostline. Dusky salamanders can survive at a variety of altitudes, ranging from sea level to high in the Appalachian Mountains. In the Great Smoky Mountains they are uncommon over 1200 m in elevation.

Range elevation: 0 to 1200 m.

Habitat Regions: temperate ; terrestrial ; freshwater

Terrestrial Biomes: forest

Aquatic Biomes: rivers and streams

Other Habitat Features: riparian

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Life Expectancy

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No specific information is available on longevity in this species. Related salamander species can be relatively long lived (i.e. several years to a decade or more) for such small animals.

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Morphology

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Desmognathus fuscus is a small but robust salamander with 14 costal grooves, and hind limbs that are larger than the front limbs. They have a keeled (knife-like) tail that is less than half the body length. The upper body varies from brown or reddish brown to gray or olive, with slightly darker markings on the top and sides. The base of the tail is typically olive, yellow, or bright chestnut (a bit lighter than the body). The belly is whitish with some dark speckles. Adults are 6.4 to 14.2 cm (2.5-5.6 in) in length. Males are typically longer than females. The average length for a male D. fuscus is 9.4 cm, and the average length for a female is 8.6 cm. Desmognathus fuscus is in the family Plethodontidae, and thus is lungless. They “breathe” via oxygen absorption through the skin and membranous tissue in the mouth and throat. Also, members of this family have a naso-labial groove, which may aid in smelling, which is important when finding prey and identifying potential mates.

Range length: 6.4 to 14.2 cm.

Average length: 9.4 (male), 8.6 (female) cm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: male larger

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Associations

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Dusky salamanders have a number of predators, including raccoons (Procyon lotor), birds, striped skunks (Mephitis mephitis), shrews (family Soricidae), water snakes (Nerodia species), garter snakes (Thamnophis species), spring salamanders (Gyrinophilus porphyriticus) and red salamanders (Pseudotriton ruber). It has been suggested that predation may impact reproductive success to the point that it restricts the abundance of dusky salamanders in parts of their range from Tennessee to Virginia. Dusky salamander skin is only mildly toxic, so they must rely on other defensive techniques. Dusky salamanders can move with great agility, and are good jumpers. They also have slippery skins which makes grasping by predators difficult. They may actually bite a predator. Like many of the plethodontid salamanders, they can drop their tails when attacked in order to distract the predator enough to make a quick escape. The tail will grow back later, though it may look slightly different than the original. Tail dropping is fairly common in northern dusky salamanders; approximately 50% of adults have missing (recently dropped) or regrown tails.

Known Predators:

  • raccoons (Procyon lotor)
  • striped skunks (Mephitis mephitis)
  • shrews (family Soricidae)
  • water snakes (Nerodia species)
  • garter snakes (Thamnophis species)
  • spring salamanders (Gyrinophilus porphyriticus)
  • red salamanders (Pseudotriton ruber)
  • birds (Aves)

Anti-predator Adaptations: cryptic

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Reproduction

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Dusky salamanders, like most members of the Order Caudata, reproduce with a unique form of internal fertilization. The male deposits a jellylike, sperm-capped glob (called a spermatophore) onto the ground. The female then climbs over the cylindrical or cone-shaped spermatophore and the sperm is allowed to enter her vent. The sperm is stored in her cloaca until breeding. Because courtship occurs both in the spring and in the fall, the sperm may be stored for either a very short period or for a length of many months.

Courtship in dusky salamanders occurs near streams in both spring and fall. Mating occurs on land. A male will approach a female while doing a "butterfly walk," rotating his front limbs similar to a swimmer doing a butterfly stroke. He will wag his tail and nudge the female with his snout in order to identify and stimulate her. Then the male will vigorously press his chin onto the female’s back and arch his body. With a quick snap, he will straighten his body. The snap is so violent that the male may be thrown 5 to 10 cm away from the female. Over time, he will repeat this activity, slowly moving until he is under the female’s head. He reaches back snaps at the female's dorsum or neck, and drags his teeth across her dorsum in order to vaccinate her with pheromone secretions that will make her receptive. Next, the female will straddle his tail, while touching her chin to the base of his tail to facilitate courtship with skin secretions. Usually, the salamanders will remain in this position for some time. Then the male will produce a spermatophore to be picked up by the female via her vent. Sometimes the male places the spermatophore directly onto her cloacal opening.

Mating System: polygynous

In summer, females produce 12 to 51 eggs, which are deposited under rocks, logs, mosses or debris near water in the summer. Larger females (based on snout-to-vent length) typically produce larger numbers of eggs. Females stay with the eggs until they hatch, after 40 to 80 days. In most successful nest sites, 70% or more of the eggs will hatch. After two or three years, males will be reproductively mature. For females, three or four years are required.

Breeding interval: Dusky salamanders can breed twice yearly, but likely only one clutch per female is produced each year.

Breeding season: Dusky salamanders mate both in the spring and the fall, but fertilization can be delayed and eggs are laid in summer.

Range number of offspring: 12 to 51.

Average number of offspring: 28.6.

Range time to hatching: 50 to 80 days.

Range time to independence: 0 to 3 weeks.

Range age at sexual or reproductive maturity (female): 3 to 4 years.

Range age at sexual or reproductive maturity (male): 2 to 3 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous ; sperm-storing

Females attend to the eggs from deposition to hatching, leaving the nest infrequently at night to feed. Brooding females will aggressively defend their clutch from predators. In one study, brooding female D. f. fuscus returned to their nests after being displaced as much as 32 meters. In the rare occurrences that females did not attend to their clutch, high mortality (often 100%) due to predation or invasion of the eggs by fungal hyphae was observed.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-independence (Protecting: Female)

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Edwards, H. 2009. "Desmognathus fuscus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Desmognathus_fuscus.html
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Hannah Edwards, Michigan State University
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Desmognathus fuscus

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Desmognathus fuscus is a species of amphibian in the family Plethodontidae (lungless salamanders).[2][3] The species is commonly called the dusky salamander or northern dusky salamander to distinguish it from populations in the southern United States which form several distinct species, the southern dusky salamanders (D. auriculatus, D. valentinei).[3] The northern dusky salamander is the most widespread representative of its genus in Canada.[3] It can be found in eastern North America from extreme eastern Canada in New Brunswick south to South Carolina.[3][1][4] The size of the species' total population is unknown, but is assumed to easily exceed 100,000.[3][1] The species' habitat differs somewhat geographically; dusky salamanders in the northern part of the range prefer rocky woodland streams, seepages, and springs, while those in the south favor floodplains, sloughs, and muddy places along upland streams.[3][1][4][5] They are most common where water is running or trickling.[3][1] They hide under various objects, such as leaves or rocks, either in or near water. Alternatively, they may enter burrows for protection.[3][4] The dusky salamander lays its eggs close to water under moss or rocks, in logs, or in stream-bank cavities. The larval stage which follows is normally aquatic.[3][4]

Taxonomy

The spotted dusky salamander (D. conanti) and the flat-headed salamander (D. planiceps) were described in the 1950s but were later thought to be synonymous with the northern dusky salamander, but further studies have found all of them to be distinct species from one another.[6][7][8]

Description

A small but sturdy salamander, the upper body of the northern dusky salamander varies in colour from reddish-brown to gray or olive, with a white or grey underside.[3][4][9] The body is sparsely covered with dark spots or mottling concentrated on the sides. It also has a light dorsal stripe or two dark stripes that continue on to the first part of the tail.[3][4] Juvenile colouring consists of five to eight pairs of dorsal spots or blotches located between the front and hind legs. Older individuals tend to be uniformly dark brown or black.[3][4] As with all dusky salamander species, both juveniles and adults have a pale single stripe outlined in black that extends from the eye and runs diagonally to the rear of the jaw.[3][4][9] Additionally, both have 14 costal grooves, larger hind limbs than forelimbs, and a keeled (knife-like) tail that is triangular in cross-section and compressed laterally at the base.[3][4][9] The tail is less than half its body length and is normally lighter in colour in comparison to the body. Adults attain lengths of up to 14 cm, with the average length of adult males and females being 9.4 cm and 8.6 cm, respectively.[3][4] Being from the family Plethodontidae, the northern dusky salamander is lungless. It absorbs oxygen through the skin and membranous tissue located in the mouth and throat.[3][9][10] The dusky salamander also has a naso-labial groove, which aids olfaction, and thus the ability to search out mates and prey through smell.[9]

A northern dusky salamander in mud.

Similar species

The dusky salamander is similar in appearance to and thus often confused with the Allegheny Mountain dusky salamander (Desmognathus ochrophaeus). Distinguishing characteristics are that the dorsal spots of the Mountain dusky salamander are usually chevron-shaped and its tail rounded at the base rather than laterally compressed.[4][11] Additionally, hybridization has been known to occur between the Allegheny Mountain dusky salamander and the northern dusky salamander.[3]

The northern dusky salamander can also be differentiated from other lungless salamanders including the eastern red-backed, the northern two-lined and the four-toed. They have a distinguishing pale-coloured line that runs from behind their eyes to the rear of the jaw, and heavier set bodies with longer hind legs than front legs.[3][4][9]

Range

This species is native to North America, and occurs throughout central-eastern regions of Canada and the United States, from southern New Brunswick , southeastern Quebec and southern Ontario south to South Carolina. Populations south of this range are now thought to belong to other, previously-synonymized species such as D. conanti.[12] The Canadian distribution accounts for approximately 5% of the global range.[3] Within its Canadian range, the northern dusky salamander usually occurs in forested habitat located in high elevation, low-order streams.[3] There are two separate units (DU), the Quebec/New Brunswick DU and the Carolinian DU in Ontario.[3] Ohio populations are reviewed in "Amphibians of Ohio" (2013).[13] An isolated breeding population exists in eastern Michigan; however, it is not known whether this population is natural or was introduced.[14]

Habitat

In the northern extent of their range, the northern dusky salamander inhabits saturated soil near springs, seepages, and small tributaries of small headwater streams otherwise known as the riparian zone.[3][1] Habitat quality is optimal in undisturbed watersheds and where water is running or trickling and there is an abundance of forest cover[3][1] The forest cover serves to keep the water cool and well oxygenated, and maintains moisture and temperature at levels necessary for salamander survival. In the south, the northern dusky salamander can be found in upland streams as well as floodplains, sloughs and muddy sites.[1]

Behavior and ecology

Predation

Northern Dusky Salamanders are an important food source for many species. They are preyed on by among others, the Eastern Garter Snake. Tail autonomy is a defense against predation[15] The species uses subterranean retreats or burrows near the streams edge as well as leaf litter, logs, rocks and moss as a source of protective cover for avoiding desiccation and predators.[3][4][5] These microhabitats are also important for foraging and nesting both of which take place on land close to the water's edge.[3][4] As a result of desiccation and predators, activity of the northern dusky salamander peaks in the morning, and the evening and early night.[16] Alongside the stream, females nest in cryptic microhabitats where soil is saturated with water. Their eggs are often laid in logs, under rocks or moss, or stream-bank cavities. During development while in the larval stage, the northern dusky salamander is strictly aquatic, its habitat the interstitial spaces between rocks of the streambed.[3] In winter, they remain in shallow running water, whereas adults overwinter in subterranean retreats or in streams, often remaining active throughout winter if the substrate doesn't freeze.[3][4]

As a relatively small amphibian, the northern dusky salamander spends most of its life in hiding.[1] If predated it is capable of autotomy along any point of its tail, but lacks chemical defense mechanisms against its main predators which include larger salamanders, birds, fish, snakes, crayfish, and small mammals.[3] known as maybe rodents or mice

The home range of the northern dusky salamander is limited to 1m2 to 3.6 m2.[3] The northern dusky salamander has seasonal variations with its patterns of movement. During warmer months the salamanders have larger home ranges that average around 1.5 m2. This is reduced during the winter and some populations move into specific areas for condensed winter retreats.[17]

Reproduction and development

dusky salamander with eggs in Page County, Virginia

Due to their lack of mobility, some populations of dusky salamander are genetically distinct.[3][18] Breeding is terrestrial and occurs annually in spring or fall and includes elaborate courtship rituals.[9] Adult males have papillose cloacal lips and a small mental gland. These glandular tissues become enlarged when sexually active.[3] Female individuals lack a mental gland and have folded cloacal lips.[3] For reproduction, the male applies the snout, cheeks and mental gland to the snout of the female, who usually responds by picking up the spermatophore.[19] Fecundity increases with body size.[3][20]

Females normally deposit between 10 and 30 eggs under logs, moss or rocks located streamside where soil is saturated with water. Clutch size has been known to vary geographically and can be as large as forty-five, or as few as eight.[3] Females remain with their eggs for an incubation period of six to ten weeks (45 to 60 days) in order to protect them from desiccation and predation .[3][4][5] The larvae are predominantly aquatic and approximately 1.5 cm in length upon hatching.[4][9] The larvae then metamorphose into semi-terrestrial adults, with juvenile salamanders being 2.8 to 4.4 cm in length. Their biphasic life cycle includes an aquatic state of seven to 16 months, followed by a semi-terrestrial adult stage. The northern dusky salamander attains sexual maturity at approximately three to four years of age.[3][4][9] Life expectancy is 10 to 15 years.[3][4]

Feeding

The northern dusky salamander is considered to be feeding generalist, with its diet based on food availability.[3][21] Stream salamanders are known to be significant predators. This is namely because they are dominant vertebrates within headwater riparian forest ecosystems, with a biomass greater than that reported for fish, birds or small mammals.[3] The species is carnivorous and consumes a variety of aquatic and terrestrial invertebrates.[3][4][9] Larvae feed predominantly on aquatic invertebrates (such as copepods, other crustaceans and insect larvae), as well as mites, whereas the adult diet consists of 60 to 85% of terrestrial invertebrates, including arthropods (such as crustaceans, spiders, mites, flies and fly larvae, ants, beetles and beetle larvae, centipedes, moths and mayflies), snails, slugs and earthworms.[9][22][23] When prey is in excess, the northern dusky salamander does typically have a preference for the larger and fleshier terrestrial invertebrates, such as earthworms.[23] The aquatic portion of the adult's diet is habitat specific and commensurate with the seasonal abundance and diversity of invertebrates.[21][3]

Conservation

Population and trends

Current data does not allow an accurate estimate of population size or trends. That said, the total adult population size of the northern dusky salamander is known to exceed 100,000 individuals.[1] There are numerous stable populations throughout the range. The species is widespread in Quebec and New Brunswick but local densities are usually low. In Ontario, the species is rare with a population size estimated at fewer than 250 individuals.[3][4]

Threats and limiting factors

The northern dusky salamander is extremely vulnerable to desiccation and therefore reliant on clean headwater streams.[10] Resultantly, contamination of ground water or waterways through pollution from urban areas, industry, or agriculture, can be catastrophic to local populations.[1] The disappearance of the species from the Acadia National Park in Maine is believed to be the result of heavy metal contamination.[3][24] Freshwater stream acidification also poses a significant threat with 40% of streams in the southern Appalachians showing signs of acidification.[3]

Changes to stream flow or the groundwater supply, can have significant impacts on local salamander genetics and populations vis-à-vis loss of suitable aquatic or terrestrial habitat, bank instability from excessive runoff, or simply changes to the moisture in the terrestrial habitat. Such changes can be naturally occurring or artificially induced (e.g. discharged water volumes). The activities of forestry can be similarly devastating. Timber harvesting, wind farms and watershed urbanization reduce water supply, water quality and microhabitat availability. Aquatic habitat can be degraded through siltation of streams, or the microhabitat conditions of the forest floor undergoing alterations. Siltation is of particular consequence to the northern dusky salamander because the interstitial spaces that they use for foraging, nesting and overwintering are lost.[3] Urbanization has resulted in the disappearance of the species in Mount Saint-Hellaire National Park in Quebec, as well as other areas.[3] Vulnerability to extirpation is further heightened when the species relies on a single watershed. Such is the case of the Ontario population of the northern dusky salamander.[4] The species is also threatened through the introduction of predatory fish, such as Brook Trout.[3]

Conservation status

The northern dusky salamander is listed as endangered in Ontario[3][4] and is declining in many parts of the United States[25][26] yet some populations remain stable.[3][4] The International Union for Conservation of Nature (IUCN) lists its global status as Least Concern.[3][4]

In the province of Ontario, where the status of the Carolinian population of the northern dusky salamander is listed as Endangered, the northern dusky salamander is protected under the Ontario Endangered Species Act of 2007 and by the Ontario Fish and Wildlife Conservation Act.[3][4][27] These acts protect its habitat and make it illegal to possess, harm or kill the species. In Ontario, a dusky salamander recovery team entitled the "Allegheny Mountain Dusky Salamander and Northern Dusky Salamander Recovery Strategy" has also been established to develop a recovery plan for both species.[18] The Quebec / New Brunswick population of the northern dusky salamander is considered not at risk.[3] Nonetheless, it is currently on a list of species likely to be designated as threatened or vulnerable by the Quebec provincial government and is also protected by a provincial act that prohibits the collecting or selling of specimens. Likewise, Article 22 of the provincial Environmental Quality Act offers protection against unregulated degradation of the dusky salamander's environment.[3] In New Brunswick, the species is designated as Sensitive under the General Status of Species in Canada. Protection is offered the species by the New Brunswick Fish and Wildlife Act.[3]

References

  1. ^ a b c d e f g h i j k Geoffrey Hammerson (2004). "Desmognathus fuscus". IUCN Red List of Threatened Species. 2004: e.T59249A11906400. doi:10.2305/IUCN.UK.2004.RLTS.T59249A11906400.en. Retrieved 16 November 2021.
  2. ^ a b Frost, Darrel R. (2018). "Desmognathus fuscus (Rafinesque, 1820)". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 19 June 2018.
  3. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb COSEWIC. (2012). Assessment and Status Report on the Northern Dusky Salamander. Environment Canada. Retrieved 7 June 2018.
  4. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z Ontario Nature. Northern Dusky Salamander Desmognathus fuscus. Ontario Nature. Retrieved 10 June 2018.
  5. ^ a b c Hom, Carole L. (1988). "Cover object choice by female dusky salamanders, Desmognathus fuscus". Journal of Herpetology. 22 (2): 247–249. doi:10.2307/1564009. JSTOR 1564009.
  6. ^ "Desmognathus conanti Rossman, 1958 | Amphibian Species of the World". amphibiansoftheworld.amnh.org. Retrieved 2021-12-22.
  7. ^ Tilley, Stephen G.; Eriksen, Renee L.; Katz, Laura A. (2008). "Systematics of dusky salamanders, Desmognathus (Caudata: Plethodontidae), in the mountain and Piedmont regions of Virginia and North Carolina, USA". Zoological Journal of the Linnean Society. 152 (1): 115–130. doi:10.1111/j.1096-3642.2007.00336.x. ISSN 1096-3642. S2CID 11305161.
  8. ^ Beamer, David A.; Lamb, Trip (2008-04-01). "Dusky salamanders (Desmognathus, Plethodontidae) from the Coastal Plain: Multiple independent lineages and their bearing on the molecular phylogeny of the genus". Molecular Phylogenetics and Evolution. 47 (1): 143–153. doi:10.1016/j.ympev.2008.01.015. ISSN 1055-7903. PMID 18337126.
  9. ^ a b c d e f g h i j k Edwards H. (2009). "Desmognathus fuscus" (On-line), Animal Diversity Web. Retrieved 10 June 2018
  10. ^ a b Moore, Cindy Marcum; Sievert, Lynnette M (2001). "Temperature-mediated characteristics of the dusky salamander (Desmognathus fuscus) of southern Appalachia". Journal of Thermal Biology. 26 (6): 547–554. doi:10.1016/s0306-4565(00)00052-8.
  11. ^ Royal Ontario Museum and Ontario Ministry of Natural Resources (2008). "Allegheny Mountain dusky salamander". Ontario's Biodiversity. Royal Ontario Museum. Retrieved 6 June 2018.
  12. ^ "Desmognathus fuscus (Green, 1818) | Amphibian Species of the World". amphibiansoftheworld.amnh.org. Retrieved 2021-12-22.
  13. ^ Amphibians of Ohio (2013); Editors: Ralph A Pfingsten; Jeffrey G Davis; Timothy O Matson; Gregory J Lipps, Jr; Douglas E Wynn; Ohio Biological Survey, Columbus, Ohio: Bulletin (Ohio Biological Survey), new ser., v. 17, no. 1., 2013.
  14. ^ BioKids - Dusky Salamander
  15. ^ Payette, WI (June 2019). "The effect of predator kairomones on caudal regeneration by Allegheny Mountain Dusky Salamanders (Desmognathus ochrophaeus)". Canadian Journal of Zoology. 97 (6).
  16. ^ Barbour, Roger W.; Hardin, James W.; Schafer, James P.; Harvey, Michael J. (1969). "Home range, movements, and activity of the dusky salamander, Desmognathus fuscus". Copeia. 1969 (2): 293–297. doi:10.2307/1442077. JSTOR 1442077.
  17. ^ Ashton, Ray E. (1975). "A study of movement, home range, and winter behavior of Desmognathus fuscus (Rafinesque)". Journal of Herpetology. 9 (1): 85–91. doi:10.2307/1562694. JSTOR 1562694.
  18. ^ a b Markle, T.M., A.R. Yagi and D.M. Green. 2013. Recovery Strategy for the Allegheny Mountain dusky Salamander (Desmognathus ochrophaeus) and the northern dusky Salamander (Desmognathus fuscus) in Ontario. Recovery Strategy Series. Prepared for the Ontario Ministry of Natural Resources, Peterborough, Ontario. pp. vi + 30
  19. ^ Virginia Herpetology Society northern dusky Salamander. Virginia Herpetology Society. Retrieved 9 June 2018.
  20. ^ Verrell, Paul A. (1994). "Males may choose larger females as mates in the salamander Desmognathus fuscus". Animal Behaviour. 47 (6): 1465–1467. doi:10.1006/anbe.1994.1195. S2CID 53166258.
  21. ^ a b Mynatt M and Mi BT. 2002. Feeding habits of seepage-dwelling dusky salamanders (Desmognathus fuscus) of Short Mountain, Cannon County, Tennessee. Journal of the Tennessee Academy of Science 77(4): pp. 88-90. ISSN 0040-313X
  22. ^ "Desmognathus fuscus (Dusky Salamander)".
  23. ^ a b Sites, Jack W. (1978). "The foraging strategy of the dusky salamander, Desmognathus fuscus (Amphibia, Urodela, Plethodontidae): An empirical approach to predation theory". Journal of Herpetology. 12 (3): 373–383. doi:10.2307/1563619. JSTOR 1563619.
  24. ^ Bank, Michael S.; Crocker, Jeffrey B.; Davis, Shirley; Brotherton, David K.; Cook, Robert; Behler, John; Connery, Bruce (2006). "Population decline of northern dusky salamanders at Acadia National Park, Maine, USA". Biological Conservation. 130 (2): 230–238. doi:10.1016/j.biocon.2005.12.033.
  25. ^ State of Connecticut. (2016, October 11). dusky Salamander. Department of Energy and Environmental Protection. Retrieved 6 June 2018.
  26. ^ Munshi-South, Jason; Zak, Yana; Pehek, Ellen (2013). "Conservation genetics of extremely isolated urban populations of the northern dusky salamander (Desmognathus fuscus) in New York City". PeerJ. 1: e64. doi:10.7717/peerj.64. PMC 3642699. PMID 23646283.
  27. ^ Government of Ontario. Northern Dusky Salamander. Ontario. Retrieved 6 June 2018

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Desmognathus fuscus: Brief Summary

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Desmognathus fuscus is a species of amphibian in the family Plethodontidae (lungless salamanders). The species is commonly called the dusky salamander or northern dusky salamander to distinguish it from populations in the southern United States which form several distinct species, the southern dusky salamanders (D. auriculatus, D. valentinei). The northern dusky salamander is the most widespread representative of its genus in Canada. It can be found in eastern North America from extreme eastern Canada in New Brunswick south to South Carolina. The size of the species' total population is unknown, but is assumed to easily exceed 100,000. The species' habitat differs somewhat geographically; dusky salamanders in the northern part of the range prefer rocky woodland streams, seepages, and springs, while those in the south favor floodplains, sloughs, and muddy places along upland streams. They are most common where water is running or trickling. They hide under various objects, such as leaves or rocks, either in or near water. Alternatively, they may enter burrows for protection. The dusky salamander lays its eggs close to water under moss or rocks, in logs, or in stream-bank cavities. The larval stage which follows is normally aquatic.

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