Posts Tagged ‘Western Pond Turtle’

Western Pond Turtle

by | December 2nd, 2014

 

What happens to conservation when the water runs dry???

Thoughts by Ashley Terry

western pound turtle

Western Pound Turtle

The Western Pond turtle (or WPT as we refer to them around the zoo) is the only freshwater aquatic turtle native to California. Traditional habitats range from Baja California to British Columbia, but in recent years that habitat has begun to shrink due to habitat destruction and the introduction of non-native species into their environment. They are now extinct in British Columbia, critically endangered in Washington and endangered in Oregon. Here in California, they are considered a species of special concern.

 

turtles

The larger of the two turtles was head started, the smaller not. Both are the same age.

Each nesting season, Oakland Zoo and Sonoma State students and biologist spend a month tracking, marking and monitoring gravid female WPT’s and viable nests at our field site in Lake County. This is the sixth consecutive year that zookeepers have spent in Lake County, and to date, we have successfully Each nesting season, Oakland Zoo and Sonoma State students and biologist spend a month tracking, marking and monitoring gravid female WPT’s and viable nests at our field site in Lake County. This is the sixth consecutive year that zookeepers have spent in Lake County, and to date, we have successfullyraised and released close to 450 turtles- each season yielding around 45 hatchlings or more – through our head start program. Check out this cool video of the WPT at the Zoo. The goal of the Head Start program is to raise the hatchlings for the first year under optimal conditions. By creating the best possible environment for the turtles, they grow 3-4 times faster than they would in the wild.  At the end of the first year, the juvenile turtles are then released back into Lake County, having grown too large to be eaten by common predators like big mouth bass and eastern bull frogs.

 

Lake County Field Site

Lake County field site

WPT’s live in typically riparian habitats where they can most often be found in sloughs, streams, and large rivers, although some may inhabit bodies of water such as irrigation ditches and other artificial lakes and ponds, too. Turtles are generally active from late May to October. WPT’s overwinter, or hibernate, in both aquatic and terrestrial habitats. Terrestrial overwintering habitats consist of burrows in leaf litter or soil. In more wooded habitats along coastal streams in central California, most pond turtles leave the drying creeks in late summer and return after winter floods.

 

Drought ridden lake

Drought ridden lake

California has experienced continuous dry conditions since 2012; alternatively known asdrought.  According to the National Drought Mitigation Center at the University of Nebraska, Lincoln, 99% of California is currently abnormally dry; 67% of California is in extreme drought, and almost 10% is experiencing exceptional drought.  The repercussions of our drought emergency are relatively simple: there is an extreme lack of water.  The absence of water impacts Californians in several different ways, whether it is economically or socially.  But how does it affect the state’s wildlife or our conservation projects here at the zoo?

western pond turtle hatching

Western Pond Turtle hatching

hatching size comparison

Hatchling size comparison

Those involved with our Head Start program have noticed that the last few drought years in the field have been incredibly stressful on the Lake County turtles in several distinctive ways. In some less permanent waters, such as our field site, the fact that the ponds have dried up completely for the first time in many years has certainly affected the behavioral patterns of WPT in some key ways, thus affecting the numbers of gravid turtles and viable nests sights during our field seasons. Since the ponds dried up by July and August of the last 2 years, the turtles were forced to estivate – spending a hot and dry season in an inactive or dormant state – when they would normally have been feeding and stocking up their internal reserves of protein and fat. The extended time they spent in this state of “suspended animation” also leaves them much more vulnerable to any manner of disturbance – especially in the case of predators, temperature extremes, etc. Lastly, and maybe most important for our head start program, the non-permanent lakes & ponds were dry when the turtles should have been feeding and mating. This was reflected in the very low numbers of nesting females last summer, giving us only 4 hatchlings this season.

 

Although these impacts of drought do indeed bring about urgent circumstances for wildlife, it is important to remember that droughts are, unfortunately, natural phenomena. Climate scientists predict that California will get even hotter and drier. As more of the state’s precipitation falls as rain instead of snow in the mountains, it will run off the land more quickly, ending up in the ocean. Scientists say that with global warming, we’ll see more instability in California’s climate, with more intense storms, longer dry periods, and less snowpack. It will be interesting in the upcoming future to see how long it takes to get back to the normal population numbers at our site, and to track the behavioral changes due to impact of habitat change. In the meantime, we are also looking at other possible locations where population numbers can be monitored. Wildlife and drought have coexisted for generations upon generations. For the most part, wildlife populations are able to bounce back from drought events once typical weather patterns return. For the time being, we’ll keep our fingers crossed for a very wet and rainy winter, resulting in turtles returning to our pond.

western pond turtle basking

Western Pond Turtles basking

 

 

 

Visit http://www.saveourh2o.org/tips to find out how you can help save water at home, and http://www.oaklandzoo.org/Conservation.php to find out more about Oakland Zoos conservation programs.

 

Western Pond Turtles get a hand at Oakland Zoo!

by | August 22nd, 2013
zena-the-zookeeperHey there, fellow conservation heroes! Do I have an important conservation program to tell you about today, and it’s taking place right here at Oakland Zoo!  It’s a ‘head start” program for the endangered Western Pond Turtle. These adorable little guys were once plentiful and lived all over the entire West Coast – from British Columbia in Canada, all the way down to Baja California near Mexico.

pond_turtle

But today, they’re only found in a few parts of California, Oregon and a couple of places in Washington State. That’s because they’ve lost a lot of their habitat and are being eaten by non-native predators – including another kind of turtle that isn’t native to California.  It’s really sad. 
 
See how tiny the baby Western Pond Turtle is?  Because they grow very slowly in the wild, it takes them a long time to grow big enough to escape or fight off non-native predators like the American Bullfrog and Largemouth Bass who love to snatch them up and snack on them. The other species bullying these guys is the red-eared slider turtle. Many red-eared slider turtles were once somebody’s pet, but people sometimes release them into the wild when they get too big, and that’s bad news for the smaller, shyer Western Pond Turtle. Our little friend loses out to the bigger guys on food resources and warm spots to lie in the sun in their habitat.
 
But the GOOD NEWS is that we are raising hatchlings right here at the Zoo in our brand-new Bio-Diversity Center!  With our ZooKeepers taking care of these babies with plenty of nutrient-rich foods and veterinary care, they grow in just one year to the size it would take them three or four years to reach in the wild. Then, when we release them into the wild they are big enough to protect themselves and have a much better chance of survival. Right now, we are raising 44 Western Pond Turtles for release next year, and the babies are doing great so far!
 
So remember fellow conservation heroes, please don’t release pet turtles into the wild.  Help keep our lake areas clean, welcoming places for Western Pond Turtles. And be sure to teach others all about the amazing Western Pond Turtle!

What Do Beavers and Western Pond Turtles Have in Common?

by | August 23rd, 2011

Keeper Kristin at the Oakland Zoo's Western Pond Turtle Table. Photo credit: Cindy Margulis

Why was the Oakland Zoo at the 4th Annual Beaver Festival in Martinez?  No, the Zoo doesn’t have beavers, but it does have Western Pond Turtles which rely on beaver habitat.  The event was a wonderful opportunity to create awareness about the Zoo’s  Western Pond Turtle Head Start Program and the conservation efforts involved to protect the only aquatic turtle native to California.  The Oakland Zoo along with many other environmental organizations participated in this festival to create awareness about native species in the Bay Area and the fragile ecosystems where the animals live.

In October of 2007 several beavers took up residence in Alhambra Creek, which is in the downtown area of Martinez, and this caused a controversy. Immediately, members of the community felt strongly about keeping the habitat intact and finding a way to co-exist with the beavers.  However, the dam was reported to pose a flooding hazard and the animals were scheduled to be eradicated.  Concerned residents took action and formed a non-profit organization “Worth a dam” to help maintain the population of beavers in Martinez through education and practicing humane environmentalism.  A special flow device was installed in the creek to manage the dam and the outcome was a success!

Dilbert, Oakland Zoo's turtle ambassador. Photo creit: Cindy Margulis

Keeper Kristin shows kids "Dilbert," Oakland Zoo's turtle ambassador. Photo credit: Cindy Margulis

Beavers are a “Keystone species” in North America because they play a critical role in biodiversity and many species rely on beaver ponds for survival.  The Western Pond Turtle will use beaver burrows and lodges to seek refuge, and the ponds provide a rich source of food for turtles, because they attract frogs, fish, and insects.

Oakland Zoo Docent Cindy Margulis and I brought “Dilbert,” the Zoo’s non-releasable turtle ambassador to the festival.  Dilbert was a hit, teaching people about the importance of protecting Western Pond Turtles, which are a ‘species of special concern’ in California.  What made the experience even more memorable for the kids was a “Keystone species” charm bracelet designed specifically for the festival.  We gave each child a turtle charm when they came up to the Zoo’s booth. The children then told us about the relationship between beavers and turtles.

Turtle charm. Photo credit: Kristin Mealiffe

Cindy and I were really inspired to see how a small group of people can make a positive change.  The Zoo’s Western Pond Turtle Head Start Program continues to be a success.  Since 2008, Zoo staff, along with researchers from Sonoma State, have released eighty-one turtles back into the wild.  The program is a joint effort with the San Francisco Zoo and Sonoma State that brings people together to help preserve a species and its habitat, so that future generations of have the opportunity to enjoy this magnificent aquatic turtle.

If you are interested in learning more about the Western Pond Turtle Head Start Program or other conservations projects, please visit our website at www.oaklandzoo.org.

Turtle University

by | June 28th, 2011

Newly hatched western pond turtle

Its turtling season at the Oakland Zoo again! Each summer our zookeepers team up with biologists and students from Sonoma State University to study the western pond turtle. Turtle nesting season is in full swing and California’s only native aquatic freshwater turtle has been an enigma to researchers for years. This is the fourth consecutive year that zookeepers have spent in Lake County and our knowledge of this species of special concern has increased exponentially. Here is just a short run down of a few of the things we have learned about western pond turtles through our collaborative research:
First, we were surprised to discover just how dry the nests were. Aquatic turtles are usually expected to have very moist nests, but not our western pond turtles. Based on our observations at the site, we created a very dry vermiculite mixture in which to incubate the eggs we collected. Several experts expressed concern about the lack of moisture in the mixture, but our guess was correct and we had a 90% hatch rate the first year.
One little known fact about many reptile species, western pond turtles included, is that the sex of the hatchling is determined by the temperature at which the egg is incubated. Along with our dry vermiculite mixture, we also set up five separate incubators at five different temperatures. The hatchlings were carefully marked with numbered dots so we knew exactly which clutch and incubator they came from. The hatchlings were then raised here at the zoo for about ten months, until they were big enough for a small endoscopic surgery to determine their sex. This data was then correlated with the incubation data and we now know the exact temperatures that produce male turtles versus female turtles.

Dr. Andrea Goodnight uses an endoscope to identify a turtle's sex.

As time went on, our project expanded and we also began to incubate nests in the field. This requires careful placement of high tech temperature and humidity sensors inside the nests and then covering the nests to secure them against predators. The wide range of temperatures in even a single day took us by surprise. Who would have guessed a difference of up to fifty degrees in one twenty-four hour period.
This is a project that is near and dear to our hearts, not only because it is a native species, but also because it is a project that zookeepers can be directly involved in. Just days ago, two keepers went to the lake to use telemetry equipment to track nesting females while other keepers were here at the zoo caring for last year’s hatchlings, who will be released at the end of this month. As we continue to progress in this conservation project, we hope to learn even more about this special animal.