Santa Cruz Long-toed Salamander
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| Ambystoma macrodactylum croceum Russell & Anderson, 1956 |
The Santa Cruz Long-toed Salamander is an endangered subspecies of the Long-toed Salamander, which is found only close to a few isolated ponds in Santa Cruz County and Monterey County, California. Its distinguishing characteristics are a well designed tail fin for swimming, a black body and a broken yellow or orange irregular striping along its spine. Like other mole salamanders it always found near pools or slow moving steams; this creature has a very secretive lifestyle, making detection difficult.
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[edit] Comparison with the common Long-toed Salamander
The Santa Cruz Long-toed Salamander has a range disassociated with the more common Long-toed Salamander; whereas the range of the Long-toed Salamander is from Tuolumne County north, The Santa Cruz long-toed Salamander is found only near a few isolated ponds in Santa Cruz and Monterey counties. Like other Long-toed Salamanders, its belly is sooty to dark brown, and it boasts tubercles on its feet. The Santa Cruz Long-toed Salamander has an irregular broken yellow striping on its back, whereas the Long-toed Salamander has a more regular yellow vertical stripe. Both species have twelve or thirteen costal grooves visible from the side.
For both species eggs are laid singly near the water surface on rushlike spikes, but sometimes in small clusters at the base of logs or adhering to vegetation in the deeper portion of a pond. In the case of both species hatching larvae are approximately ten millimeters in length; in their first summer they grow to a length of 50 to 100 millimeters, but the Santa Cruz Long-toed Salamander is generally considered the smallest of the species. The precise times of migration for both species to and from the breeding ponds are keyed to nocturnal periods of sustained rainfall.
[edit] Valencia Lagoon, the modern discovery site
On December 2, 1954 the Santa Cruz Long-toed Salamander was discovered in Valencia Lagoon by R.W. Russell and James Anderson. This small seasonal lagoon clogged with cattails in Aptos, California measured only about 30 meters by 150 meters at that time. Caltrans filled half of the lagoon with a widening of State Route 1 in the year 1968. The next study of Valencia Lagoon occurred in 1974 by Earth Metrics, whose staff examined the lagoon to develop further mitigation strategies to allow the creature to better breed and migrate; that study also called for the permanent protection of Valencia Lagoon, which was later effected when the State of California purchased the lagoon. Hogan's study also noted the adverse effects of siltation that were occurring in Valencia Lagoon from the highway embankment erosion created by widening of Route 1; it was reasoned that the siltation should decrease once the vegetation became re-established on these slopes and allow the habitat to improve; moreover, the Earth Metrics study derived additional mitigation for the county of Santa Cruz to follow in considering any further discretionary actions around Valencia Lagoon. Another mitigation breeding area in the same drainage along Bonita Road was set aside as a protected area.
[edit] Life cycle
Most of adult life is spent in upland Coast Live Oak forest in small animal burrows during the long dry season of coastal California. The first rains start in October, triggering surface activity and the preparation for migration of males to the breeding ponds. These trecks of up to two kilometers find the males arriving to the ponds in January just before the females. The courtship and swimming mating ritual occurs at night within the pond. Only when the mate selection is secure does the male deposit a spermatophore in the water which is retrieved by the female to effect fertilization. Eggs may be laid singly or in loose clusters of six to eight shallower depths of five to eight centimeters.
The untended eggs hatch in March, and metamorphosis occurs when the pond begins to desiccate, so that metamorphasis is complete prior to the drying of breeding ponds. The larvae compete with other amphibian larvae, with whom they are sympatric. Predators may include aquatic invertebrates, garter snake and other vertebrates (California's Wildlife, 1988). It is essential for this salamander that the breeding pond completely vanish; otherwise, a year round pond can harbor predators such as frogs and fish, who would decimate the young. The juveniles commonly eat copepods before their first journey to the upland forest; however, it is not uncommon for juveniles to spend their first summer quite close to the breeding pond in a rodent burrow or rock fissure, before migrating up to the forest in the case of A. m. croceum. Other long-toed salamander species may migrate slightly earlier after coming on land and not spend their first summer near the pond. This fact may be due to the ponds of A. m. croceum retaining summer water, whereas some of the other species breeding ponds dry up entirely over the summer.
[edit] Outlook for this species
Ambystoma macrodactylum croceum is a protected by having been designated as an endangered species by both the State of California and the Federal Government; however, its very limited range and fragile specialized habitat are severe restrictions to the viabiltiy of this species. There is no definitive population estimate for the Santa Cruz Long-toed Salamander; however, the numbers are deemed to be quite small. Further disturbance of habitat or incursions therein by man or domestic animals could lead this species to extinction (Bury, 1972).
[edit] References
- C. Michael Hogan et. al., Environmental Impact Report for Stern Medical Office Complex, Aptos, prepared for Santa Cruz County by Earth Metrics Inc., Palo Alto, California (15 October, 1974)
- 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.
- Federal Register, 32, 4001, March 11, 1967
- 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)
- John L. Behler, Field Guide to North American Amphibians, National Audubon Society (1996)
- L.G. Talent and C.L. Talent A Population of the Endangered Santa Cruz Long-toed Salamander {Ambystoma macrocactylum croceum) Monterey County, California, California Department of Fish and Game 66: 184-186 (1980)
- R.C. Stebbins, A Field Guide to Western Reptiles and Amphibians, 2nd ed. Houghton Mifflin (1985)
- S.B. Ruth, The Life History and Current Status of the Santa Cruz Long-toed Salamander,Proceedings of California Herpetology (H.F. DeLisle, P.R.Brown, B. Kaufman, B.M. McGurty editors, Southwestern Herpetologists Society
