TOPANGA MESSENGER (California) 15 August 03 Topanga Turtles Subject of Santa Monica Bay Restoration Commission Study Grant (Lynda Pasco)
Western Pond Turtles (clemmys marmorata) are listed in California as a species of special concern. Once common in all the coastal drainages from Mexico to the Canadian border, due to habitat loss and increased predation over the years their population has severely decreased.
The Western Pond Turtle Study has been instituted to gather information which will aid in the long-term protection of the remaining turtles. Two possibly independent turtle populations are being studied on Conservancy land three miles apart, and turtle tracking will help provide a better idea of their seasonal habitat usage. This information will enable the study team to provide management recommendations, ensuring continued survival for the pond turtles.
The study is funded by a grant from the Santa Monica Bay Restoration Commission and administered by the California Coastal Conservancy. Additional donations in the amount of $2,100 were received from private parties including the Westchester chapter of the California Turtle & Tortoise Club. These donations helped purchase transmitters used in tracking the turtles. To date, 137 turtles have been located.
Data collection began in May 2002 under the supervision of chelonian expert Dr. Dan Holland and the staff of the Resource Conservation District of the Santa Monica Mountains, RCD. The study seeks to answer questions about the size of the turtle population, their preferred habitat and survival ratio, as well as where they are located, where there is successful nesting and when they are most active.
To date, 60 volunteers have contributed over 700 hours doing mapping, behavior observation, tracking and data documentation. The teams have been active not only with the turtles, but with their environment as well, measuring pond water depth, rainfall statistics, local temperatures and available foods. GIS mapping is also done, to gauge how far a turtle has to walk to get from one population to another.
Western Pond Turtles can grow to 8 inches and live about 40 years. An average carapace (shell) size is 110 to 210 millimeters. Gravid females are typically larger than males, and will lay from one to six eggs in spring. Hatchlings emerge in approximately 12 weeks.
The turtles are protected by law, which is necessary to limit their collection for the pet trade. Both species of Western Pond turtle—clemmys marmorata marmorata and clemmys marmorata pallida are listed as endangered.
What makes these turtles special is their adaptability to both moist and dry climates. In late summer when streams and rivers are drying up, they migrate to remaining pools and pockets of moisture, sometimes over long distances. Their survival is assured by digging themselves into the mud on the bottom of available water courses. Pond turtles can tolerate salt water for a short period of time but prefer fresh or brackish water and large rocky areas with plenty of vegetation. They are secretive and elusive, spending their time swimming, feeding and basking in the sun.
The report on the first year of this study, May 2002-2003, has been released by Rosi Dagit of the RCD. It documents data collected on the turtles, including size, sex, weight, approximate age and habitat preference. It also documents Topanga’s trees, shrubs, perennials, annuals, amphibians, reptiles, birds and mammals. The study will continue until May of 2004 and will show how these factors affect the turtles and give a better picture of the their habits, cycles and successes.
Rosi Dagit will be heading a field trip on Friday, September 5 at Turtle Dreams in Santa Barbara. She will also be speaking at the California Turtle & Tortoise Club Symposium on Saturday, September 6 in Carson.
For more information, visit the California Turtle & Tortoise Club website at www.tortoise.org.
Topanga Turtles Subject of Grant