Research

Howie Wier Memorial Conservation Grant 2007-08
Award Recipient Thomas Devitt, University of California, Berkeley

Here’s what Tom Devitt has to say about salamanders and his research. . .

The Large-blotched Ensatina is a salamander that inhabits forested areas of the Peninsular Range region of southern California and northern Baja California. It resembles a lizard in overall appearance, having four legs and a tail, but unlike lizards (which are reptiles), it lacks scales and claws and has smooth, moist skin, like most other amphibians. People rarely see these secretive animals because they are active only at night, and take refuge under logs, rocks, and other debris during the day. These salamanders lack lungs altogether, and must breathe through their skin. Because of this, they are tied to moist areas and are most active during the wetter months of the year. Unlike many other amphibians that lay their eggs in water, which then hatch into aquatic larvae or tadpoles and then transform into adults that live on land, female Large-blotched Ensatina salamanders lay their eggs on land in moist, sheltered areas. Females remain with the eggs until they hatch into fully-formed miniature adults after about 3 months.

Unfortunately, like many other plants and animals found in southern California, the Large-blotched Ensatina salamander is increasingly threatened by development, fires, agriculture, logging, and climate change. Despite being classified as a California Species of Special Concern and a Forest Service Region 5 Sensitive Species, basic information is lacking on the status and distribution of populations of this salamander. As part of my dissertation research, I am investigating the population biology of this threatened species. Working primarily in Palomar Mountain and Cuyamaca Rancho state parks, I am trying to answer basic questions such as: How many Large-blotched salamanders are there? How far do they move? How long do they live? Are populations that are geographically separate from one another genetically distinct? How do these salamanders respond to fire? What are the immediate threats to this species’ survival, and how can we best conserve the Large-blotched Ensatina and its habitat? To answer these questions, my research combines both fieldwork and molecular genetic laboratory work. I capture salamanders in the field and individually mark them using a tiny numbered tag that is injected just underneath the skin. The procedure is quick, and the salamanders are released unharmed. I also remove a small piece of tissue from the tip of the tail of the salamanders (which regenerates) to use for later genetic analyses. Genetic data may aid in identifying any distinct populations, and is also useful for estimating levels of connectivity between isolated populations. I revisit areas year after year, and based on how many animals I recapture which were marked previously, I can then estimate the size of populations, how far animals have moved, and generally how well salamanders are surviving.

I’m often asked, “What are salamanders good for?” or “Why should we care about them?” The answer is straightforward: these salamanders play a direct role in a variety of ecosystem processes, and they provide humans with easily quantifiable measures of ecosystem health and integrity. Amphibians are the proverbial “canary in a coal mine” and are disappearing at an alarming rate: over one-third of all species world-wide are considered threatened or endangered due to human-induced changes such as habitat loss and fragmentation, introduced species, emerging infectious diseases, and climate change. For more information about amphibians in general, or about the Large-blotched Ensatina in particular, please visit AmphibiaWeb

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