Western Pond Turtle Recovery Programme

To breed and reintroduce western pond turtles to supplement stocks in the USA

 

The initial cause of the decline of the western pond turtle, lemmys marmorata, in Washington may have been commercial exploitation for food. Western pond turtle populations cannot endure such exploitation, due to their low rate of reproduction and the challenges of living at the northern end of their range. Pond turtles never recovered from this decline, in part, due to loss of habitat. Wetlands were filled for residential and industrial development, particularly in the Puget Sound region. Dam construction and water diversion projects reduced available habitat and isolated populations. Human disturbance kept females from crossing over land to lay eggs, and reduced the amount of time spent basking, which in turn, is important for egg maturation. Loss of lakeside emergent wetland vegetation to grazing and trampling made habitat less suitable for hatchlings and juveniles. Preventing fire on native grasslands may have caused overgrowth of plants which would have resulted in excessive shade on nesting grounds. Introduced predators such as bullfrogs and warm-water fish, which were introduced to lakes and ponds, ate nearly all the hatchling turtles.

 

The goal of the recovery program is to establish self-sustaining populations of western pond turtles in the Puget Sound and Columbia Gorge regions. The recovery objectives are to establish at least five populations of approximately 200 pond turtles, composed of no more than 70% adults, which occupy habitat that is secure from development or major disturbance. It is also necessary that the populations show evidence of being sustained by natural recruitment of juveniles. The core pond turtle sites should be wetland complexes that may be less susceptible to catastrophes than sites of a single water body. The recovery objectives need to be met before the western pond turtle would be considered for downlisting to threatened. Objectives for downlisting to sensitive are similar, except seven populations of approximately 200 pond turtles will be needed.


Since 1990, a head-start program - where eggs are taken from certain sites, hatched and the young raised until they are an adequate size for release - has been used to improve the chances of survival for hatchling turtles from wild nests. Control of introduced predators and habitat enhancement efforts are ongoing where western pond turtle populations are found. The Washington Department of Fish and Wildlife (WDFW) has acquired land in Klickitat County that supports the largest surviving western pond turtle population in the state. A captive breeding program at Woodland Park Zoo has produced 45 turtles for release into suitable Washington habitat, and a total of 620 headstart juvenile turtles have been released back to the wild in Puget Sound locations and the Columbia Gorge. A new population is also being established at a site in the Columbia Gorge. Beginning in 2001, headstarted and captive-bred turtles from the early years of the program have begun to nest.


The total number of western pond turtles in known Washington populations is estimated at only 500-600 individuals, approximately two-thirds of which went through the head-start program at Woodland Park Zoo. Oregon Zoo is now also participating in the head-start program. The western pond turtle is declining throughout most of its range and although the recovery project has made significant gains, this species is still highly vulnerable to extirpation in Washington. The species requires a continuing recovery program to ensure its survival in our state. The Western Pond Turtle Recovery Project represents a highly successful conservation partnership, in which a government agency - WDFW - has joined with Woodland Park Zoo and Oregon Zoo to save one of our state's rarest animals.

 

WAZA Conservation Project 05033 is implemented by the Woodland Park Zoo and Oregon Zoo, in partnership with the Washington State Department of Fish and Wildlife, Nature Conservancy, U.S. Forest Service, Western Aquatic Turtle Education and Research, and supported by the American Zoo and Aquarium Association's Conservation Endowment Fund.

 

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