Long-toed Salamander
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| Long-toed salamander | ||||||||||||||
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| Ambystoma macrodactylum Baird, 1849 |
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A. m. columbianum |
The range of the Long-toed Salamander, Ambystoma macrodactylum, extends from south-eastern Alaska south to Tuolumne County in northern California, and from the Pacific coast east to north-central Idaho and western Montana (Petranka 1998). Found in a wide variety of habitats from coniferous forests, especially Ponderosa pine; montane riparian; sagebrush plains; red fir forest; to wet alpine meadows. Found on the ground under bark, rocks, and rotting wood piles in its terrestrial phase, it lives in quiet streams, ponds and lakes during its aquatic breeding phase (Stebbins, 1995). Amazingly, this species is found to occur at sea level and up to 2800 meters in elevation.
The subspecies A. m. croceum (Santa Cruz Long-toed Salamander) is an endangered species with a very narrow range of habitat in Santa Cruz County and Monterey County, California. A principal distinguishing characteristic of the Santa Cruz Long-toed Salamander is the nature of its more irregular yellow pattern on its back. Other known subspecies are Ambystoma macrodactylum columbianum, A. m. krausei, A. m. macrodactylum and A. m. sigillatum.
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[edit] Detailed habitat requirements
During the dry months beginning in April, the primary food source is arthropod, chiefly spiders, isopods and insects. But after the Pacific storms start in October, the food source gradually switches to aquatic dipterans along with terrestrial insects. After hatching, the larval stage feeds on small aquatic crustaceans (cladocerans, copepods and ostracods), aquatic dipterans and tadpoles (Anderson, 1968).
Most of the year (that is, during the long dry late spring to fall), adults live in subterranean style, usually in small rodent burrows or in rock fissures. During the migration to the breeding pond, adults may utilize cover of fallen logs or surface rocks. Terrestrial juveniles, especially A. m. croceum, may spend the whole summer in a rodent burrow or rock fissure close to the breeding pond. Aquatic larvae prefer shallow water less than 30 centimeters deep, and find vegetative clumps or benthic debris as cover.
[edit] Life Cycle
Life history varies greatly with elevation and climate. Each season individuals migrate to breeding ponds, with males arriving earlier and staying longer than females (Beneski et al 1986). This salamander begins migrating from upland habitat journeying to his breeding ponds when the snowmelt is sufficient to feed the (often) seasonal ponds. At low elevations and in the case of A. m. croceum this migration is in October or November to January (Petranka, 1998). The precise times of migration to and from the breeding ponds are keyed to nocturnal periods of sustained rainfall, including initial juvenile migration.
After an aqueous courtship dance, males deposit spermatophores (packets of sperm) in the water, which females retrieve. Single eggs or loose egg clumps are attached to vegetation or detritus. Larvae hatch two to six weeks later and metamorphose in about three months (Petranka, 1998). The female deposits typically eight to ten eggs in a loose cluster about 27 to 75 centimeters in depth on the undersides of wood detritus or other submersed objects or plants. In the case of A. m. croceum, eggs may be laid singly or in loose clusters, but at much shallower depths of five to eight centimeters. Larvae metamorphasize prior to the drying of breeding ponds, except for higher elevations where juveniles may overwinter.
[edit] See also
- Santa Cruz Long-toed Salamander, an endangered subspecies
[edit] Bibliography
- California Wildlife, Volume I, Amphibians and Reptiles, ed, by David C. Zeiner, William F. Laudenslayer and Kenneth E. Meyer, published by the California Department of Fish and Game, May 2, 1988.
- J.D. Anderson, A Comparison of the Food Habits of Ambystoma macrodactylum sigillatum, Ambystoma macrodactylum croceum and Ambystoma tigrinum californiense', Herpetologica 24: 273-284 (1968)
- J.W Petranka, Predator Prey Interactions among fish and larval Amphibians: Use of Chemical Cues to Detect Predatory Fish, Journal of Animal Behavior 35:420-425 (1987)
- J.W. Petranka, Predation by tadpoles of Rana sylvatior on embryos of Ambystoma, Herpetologica, 54: 1-13 (1998)
- Robert C. Stebbins and Nathan W. Cohen, A Natural History of Amphibians, Princeton University Press ISBN 0-691-10251-1 (1995)
[edit] References
- Hammerson (2004). Ambystoma macrodactylum. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 09 May 2006. Database entry includes a range map and justification for why this species is of least concern
