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SACRAMENTO FWO: Sonoma County Annual Survey Keeps Population Data Rolling In
California-Nevada Offices , April 16, 2009
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David Cook (center), a herpetologist and senior environmental specialist for the Sonoma County Water Agency, based in Santa Rosa, has organized the yearly survey and workshops since 2000. (photo: Steve Martarano USFWS)
David Cook (center), a herpetologist and senior environmental specialist for the Sonoma County Water Agency, based in Santa Rosa, has organized the yearly survey and workshops since 2000. (photo: Steve Martarano USFWS) - Photo Credit: n/a
A few examples of the California tiger salamander larval from the survey at the Southwest Park Vernal Pool Reserve in Rohnert Park. (photo: Steve Martarano USFWS) 
A few examples of the California tiger salamander larval from the survey at the Southwest Park Vernal Pool Reserve in Rohnert Park. (photo: Steve Martarano USFWS)  - Photo Credit: n/a

by Steve Martarano, Sacramento FWO

ROHNERT PARK – It’s a beautiful March afternoon in Sonoma County about 50 miles north of San Francisco, and about 40 volunteers are wading into a dozen ponds looking for young samples of the endangered California tiger salamander (CTS). This large salamander is endemic to the lowlands of central California and lives a secretive life, spending most of its time underground. But for a few months in the spring CTS larvae can be found in breeding pools and ponds. This is when biologists grab their dipnets and head to the pools.

 

The breezy, cool and clear weather meshes well with the enthusiasm of the workers as they get their instructions. They know this is an important job, and the data they come up with will be valuable for several state and federal agencies as they work to understand population dynamics. The group is part of the annual Rare Pond Species Survey Techniques Workshop; “cheap labor,” as workshop/survey leader David Cook calls the effort. The survey efforts will eventually include almost 100 vernal pools on the Santa Rosa Plain and an additional three ponds that are a part of on-going conservation efforts.

 

Cook, a herpetologist and senior environmental specialist for the Sonoma County Water Agency, based in Santa Rosa, has organized the yearly two weekends of on-the-job survey and workshops – which for several years was funded by FWS – since 2000. On the afternoon of the CTS survey at the Southwest Park Vernal Pool Reserve, the group is comprised of biologists from several agencies from northern California, including the U.S Fish & Wildlife Service, California Department of Fish and Game, CalTrans, the City of Oakland, and other conservation groups.

 

After a dinner break that Friday (the surveys/workshops covered seven days over a two-week period), the group returned to a nearby cluster of ponds, looking for another endangered species residing in Sonoma County, the California red-legged frog.

 

“These surveys are always a good chance to get out and get a feel of what we normally just talk about from our offices, so that we can better understand the ecology and life history of these two species,” said Arnold Roessler, the former Listing Branch chief at FWS’ Sacramento Fish & Wildlife Office, now head of the Forest/Foothills Branch. “It helps a wide variety of agencies, including us, to monitor population – whether the numbers are increasing, decreasing, or staying the same. The workshops are also a good chance to make people aware of the procedures and protocols of surveys.”

 

Vincent Griego, an FWS biologist who has headed up the formation of several conservation banks, including one recently at the survey site, said the surveys are important for several reasons, including obviously showing the presence/absence factor or successful breeding of a listed species in a particular area.

 

“The surveys show us the importance of the vernal pools,” Griego said. “They can show us what predators might be there impacting the listed species, and the data helps us develop conservation strategies and other management activities.”

 

That survey/workshop weekend, crews worked a total of about 100 pools in the area. Because this was another dry year, with rains coming later than usual, populations were not expected to be high, and they weren’t. Normally, workers will find breeding populations of CTS in 39 of those pools; this year the number was less than 20.

 

This long-term study helps distinguish between natural population changes due to fluctuations in annual rainfall and true population declines.

 

“Because this species can adapt to varied environmental conditions, it’s either bust or boom,” Cook said. “This is the 10th year I’ve done this survey, and I’m used to the up and down nature of the population. If this was my first year doing it, I may want to press the panic button. But I’ve seen the down cycles before, so I’m not worried.”

 

CTS, found only in California, has been listed as Endangered since March 2003 for both the Sonoma and Santa Barbara populations. The Central California population of CTS was listed as Threatened in August 2004. The species, which measures a little over 8 inches long when mature, is restricted to grasslands and low elevation foothill (typically below 3,600 feet) regions where lowland aquatic sites are available for breeding. CTS prefer natural ephemeral pools or ponds that eventually go dry, but stockponds are an important habitat component for the species. Whether the criticism is fair or not, CTS are often pointed to by developers claiming their presence often hold up projects. In Sonoma County CTS only occur on the flat Santa Rosa Plain, which is prime lands for residential and vineyard development.

 

While in the coastal regions, populations are scattered, the Sonoma population appears to have been geographically isolated for some 700,000 years from the remainder of the CTS population by distance, mountains and other major waterway barriers.

 

Cook is considered one of the top experts on CTS in the area. Last year, he proposed a unique road crossing be built under Stony Point Road near Cotati just a couple of miles from the recent CTS surveys to protect CTS migrating across the road to breed. For a similar problem at Stanford University, a special culvert was installed so that CTS was able to move from a pond to nearby uplands. That project was successful, Roessler said.

 

“We find a few dozen to 60 salamanders every year crossing the road, and half are dead,” Cook told the Santa Rosa Press-Democrat last December. Cook said the $150,000, three-tunnel project was recommended for funding as part of a $10 million CalTrans-sponsored grant program. He is now waiting for final approval.

 

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More information about this species is avaible on the Service web:

Learn more about California tiger salamander

Species Profile

 

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Contact Info: Steve Martarano, 916-930-5643, steve_martarano@fws.gov



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