Tag: reintroductions

Native Turtles Return to Mountain Lake

- Wendy St. John 1 Comment

Originally posted on the San Francisco Bay Area National Parks Science and Learning Blog

Although no one knows exactly when western pond turtles vanished from Mountain Lake in the Presidio of San Francisco, they are known to have been abundant historically. Now, as part of the ongoing restoration of Mountain Lake, this long-extirpated species is back. On July 18th, 28 western pond turtles reared by the San Francisco Zoo were released into the lake before an audience of more than 70 people. The release follows similar releases of other native species including Pacific chorus frogs and three-spined sticklebacks earlier in the year.

The western pond turtle release is also part of a research effort to determine which of two different release methods is better for the turtles in terms of their stress hormone levels. Half of turtles were brought to Mountain Lake and kept in a protected enclosure for three weeks to acclimate ahead of their release, while the rest were released without an acclimation period. All had their stress hormone levels measured upon their release and are equipped with radio transmitters so they can be relocated and have their hormone levels re-measured in the coming weeks and years. The preliminary results will inform another round of western pond turtle releases at Mountain Lake on September 12th and contribute to knowledge about native species reestablishment efforts in general. Future reestablishment projects at Mountain Lake may include the Pacific newt and the California red-legged frog.

Check out the SF Gate article or the Bay Nature article for additional coverage of the recent western pond turtle release.

Ready, Set, Reintroduce!

- Wendy St. John 1 Comment

Originally posted on the San Francisco Bay Area National Parks Science and Learning Blog

The Presidio’s Mountain Lake restoration is moving forward this year with several native species reintroductions. The Sierran chorus frog (Pseudacris sierra), is slated to be the first species reintroduced. This species was extirpated from the Presidio sometime in the 20th century and, although common throughout its range, has become very rare in the city of San Francisco. The first phase of the reintroduction will take place in February, when chorus frog egg masses will be placed in protective enclosures to keep them safe from predators as they acclimate to Mountain Lake. The tadpoles that hatch in those enclosures will then be released into Mountain Lake in March. Later in the year, threespine stickleback and the Western Pond turtles will also be reintroduced to the lake.

Reintroduction projects offer a wide range of opportunities for scientific exploration and citizen science engagement, so the Presidio Trust has been partnering with several organizations and institutions to broaden impact and expand knowledge in the fields of reintroduction biology and urban ecology. For instance, partners at Stanford University just published research on the potential to achieve improved water quality from the reintroduction of freshwater mussels, and the California Academy of Sciences produced an excellent video on the Mountain Lake restoration, including upcoming species reintroductions. Keep an eye on the Presidio Trust website and social media for more reintroduction-related news and events throughout 2015. It’s an exciting time in the history of Mountain Lake!