A Wet and Slippery Census

By KEVIN F. SHERRY

June 6, 2001 12 AM PT

SPECIAL TO THE TIMES

Think of it as “The Crocodile Hunter”--but on a smaller scale.

For the past several months, biologists from the Santa Monica Mountains National Recreation Area have been climbing steep hills and lugging equipment through creeks to catalog the reptiles and amphibians that make their homes in the area.

The National Park Service thinks about 35 species of reptiles and amphibians live in the mountains. Of those, 13 species are considered rare, threatened or endangered.

The main purpose of the project is simple exploratory science.

“The national park wants to know what’s in their parkland,” said Gary Busteed, head of the inventory monitoring program.

After that has been established, the reptile and amphibian populations can be monitored to determine what effects urbanization and other changes have on habitats and breeding.

“We can [speak] with authority when commenting on species and development,” Busteed said. “We have proof to back that up.”

The Santa Monica Mountains National Recreation Area stretches south of the Ventura Freeway from Point Mugu to the San Diego Freeway. The area also includes Cheeseboro and Palo Comado canyons in the Simi Hills and the entire stretch of Mulholland Highway from Leo Carrillo State Beach to Hollywood.

The 28-year-old Busteed, an Alaska native who has surveyed birds near the Arctic Circle, is conducting the reptile portion of the program as part of his work toward a master’s degree in biology from Cal State Northridge.

He is concentrating on locations in the wild--both in and around parklands--throughout eastern Ventura and western Los Angeles counties, based on their size and proximity to more developed areas.

“We’re looking to see if the diversity and abundance of these species changes with the different impacts of urbanization,” Busteed said.

To catch lizards, Busteed stakes black landscaping cloth to form three 15-meter-long barriers along the ground in the shape of a Y. Biologists dig holes and place a five-gallon plastic bucket at the center of the Y and two along each of the three arms. When lizards encounter one of the barriers, they tend to run along them and fall into one of the buckets, which are flush with the ground.

Each array also includes snake traps, which are cylinders with funnel-shaped entrances. Snakes wriggle in to find shelter from the sun and cannot find their way out again.

Water-soaked sponges in the buckets keep the animals cool until biologists catalog and free them.

Busteed and his teams have placed 22 such arrays throughout the mountains, for a total of 154 traps. Biologists check the traps daily to record and release anything captured. Each set of traps is left for 10 days.

When biologists find a lizard in a trap, they note the location and record the animal’s weight, length and sex. The biologist then clips a segment of a toe off each five-digit appendage, which helps indicate whether an animal has been captured more than once.

The scientists also cut a segment off the end of the lizard’s tail before freeing it. All the snipped pieces are sent to a lab for testing, to determine the individual’s genetic relation to other members of its species.

Since the start of the ID program, biologists have caught and cataloged more than 700 lizards of various types. One of the more common species is the Western fence lizard, also called a blue belly. The males of the species perform what look like push-ups, flashing the two bright blue stripes on their stomachs to mark territory and attract mates.

Biologists also have found side-blotch lizards and Western skinks with sky-blue tails, as well as whiptails and alligator lizards. The snake traps have produced king snakes, gopher snakes and rattlers.

The amphibian portion of the project is more labor-intensive. Biologists chose 30 streams representing the various types of habitat in the Santa Monica Mountains. They aim to visit each stream once a year to measure how populations of amphibious species such as frogs and newts change over time.

Amphibians can live for several years, and because their skin absorbs oxygen from the water, their health depends on the quality of streams.

“Their skin is very permeable, so things can get in really easily,” said Jake Kerby, a biologist and volunteer with the park service. “All the other animals have some sort of protection.”

The teams begin their survey from the same starting point in each creek each time. They start by measuring the speed, temperature, salinity, pH level and oxygen content of the water.

They then wade 500 yards upstream, measuring the width and depth of the water.

Sometimes this data gathering requires jumping into chest-high water, ducking under fallen trees or climbing up miniature waterfalls.

The amphibians help gauge if man-made chemicals--such as fertilizers containing nitrates and phosphates--have made it into the creek.

“They’re good indicators of environmental quality,” Busteed said. “If we start to see a disappearance, we know something drastic is happening.”

On a recent day in Liberty Creek south of Agoura Hills, long strands of hair-like algae provided shelter for tadpoles, water striders skimmed across the surface, and bright blue or red dragonflies searched for mates.

“Everything that’s flying around here has an aquatic stage,” Kerby said.

Occasionally a barn owl swooped overhead, and a hummingbird stopped to take a drink. Near the water sat a Pacific tree frog, with black stripes across its eyes for camouflage. In the stream, tiny whirligig beetles--with a pair of eyes on both the top and bottom of their heads allowing them to see what’s happening in the air and underwater simultaneously--zipped around the surface.

Such diversity of species bodes well for a stream. The more kinds of animals found in an area, the healthier that area usually is, Busteed said. Young animals, which are most vulnerable to chemical changes in the water, are particularly important to the study.

“One reason we do the survey this time of year is we’re looking for presence of reproduction,” he said.

A cylinder with a pane of clear plastic on the end allows scientists to peer into the depths of the creek to count tadpoles. Busteed also monitors how erosion has affected the creek. If too much sediment finds its way into the water, small cracks between rocks can be filled, leaving little room for invertebrates.

Liberty Creek might look healthy on the surface, but the data provide a more complete picture, Kerby said. “You can see there’s not much life here,” he said. “It looks like a nice, peaceful stream. [But] there are animals that just can’t survive in here.”

While the absence of certain species can indicate an environmental problem with a stream, the presence of certain other species can also be problematic. The 26-year-old Kerby, who also is working toward a master’s degree in biology at CSUN, volunteers his time with the amphibian project because it gives him a chance to monitor which streams have been affected by crayfish, a nonnative invasive species that can disrupt the natural ecosystem.

“People come home from fishing trips and they just toss them into the streams,” Busteed said. “They’re very hard to get rid of, and they’ll eat everything.”

The Louisiana crayfish, which can grow to be about 4 1/2 inches long, are bad news for newts. Crayfish consume clusters of newt eggs and can munch the tails off the adults.

“If they get into all the streams, they’ll wipe out the California newts,” Kerby said.

Kerby has found seven local streams overrun with crayfish. Mosquito fish and omnivorous bullfrogs--which are also nonnative--can move into a territory and devastate native species, Kerby said.

Aside from the one-time costs of equipment--all of it fairly low-tech--the monitoring program involves little expense, other than salaries for the park service employees, Busteed said.

Ultimately, the information collected will help scientists monitor changes in the animal populations. The information also could be used by those outside the park service, Kerby said.

For example, developers could use the data to show that a certain project would not harm a nearby creek, he said. Likewise, environmentalists could use the information to oppose a project because it would damage key lizard habitat.

Thousand Oaks biologists also could use the information, said Rick Burgess, an associate planner with the city.

City biologists determine which species might be affected by a development and try to plan around them, he said.

If a particular animal is threatened, that “may result in redesign,” Burgess said. “Generally what you try to do is avoid the population.”

Ultimately, the survey aims to monitor changes--many of which are subtle and occur over long time periods--to ecosystems in the park. “What we worry about,” Busteed said, “are the things you don’t see.”

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

The Cast of Characters

The following animals have been recorded thus far in the reptile and amphibian identification project:

Alligator lizard

Blind snake

California coast horn lizard*

California king snake

California mountain king snake*

California newt*

California tree frog

Coastal wood tail*

Ensatina salamander