Hungry goats restore bog turtle habitat.
In Maryland, where the species listed as threatened, bog turtles are known to occur in Cecil, Harford, Baltimore, and Carroll counties. Besides illegal collection for the pet trade, the primary threat to bog turtles is the loss of the wetlands on which they depend. Saturated, springfed wetlands, such as bogs, fens, wet meadows, sedge marshes, and pastures with soft muddy areas, provide the habitat these turtles require for feeding, breeding, and hibernation. Development, shifts in land use, woody plant succession, and encroachment of invasive plants contribute to the loss or alteration of bog turtle habitat.
One hypothesis suggests that, prior to settlement by Europeans, bog turtle wetlands were grazed by large herbivores, such as bison, that helped to maintain the open canopy and pockets of muddy substrate. Over the last century, the abundance of bog turtles in pastured wetlands indicates that grazing cattle have been instrumental in maintaining the openness of wetlands needed for habitat. In the absence of grazing, most shallow wetlands give way to woody vegetation or dense thickets of exotic invasive plants like multiflora rose (Rosa multiflora).
Some bog turtle wetlands have been overgrazed by cattle, so habitat restoration work included stream fencing, pasture management, and creating alternative water resources for livestock. Other bog turtle wetlands have been overgrown with woody shrubs, small trees, and invasive plants. Restoration of these overgrown wetlands typically requires labor intensive removal of vegetation using physical, mechanical, and chemical treatments.
In 1997, the New Jersey Division of Fish and Wildlife's Endangered and Nongame Species Program began to experiment with livestock grazing to control woody vegetation in bog turtle wetlands. Since then, prescribed grazing has been successful in bog turtle sites in North Carolina, Georgia, Virginia, New Jersey, New York, and Pennsylvania.
Cattle are most adept in grazing on and controlling grasses, but goats are woody vegetation specialists. They can control species such as young red maple (Acer rubrum) trees and multiflora rose. In 2007, the Maryland Department of Natural Resources, in partnership with the Fish and Wildlife Service's Chesapeake Bay Field Office, the Maryland Cooperative Extension Service, and the federal Natural Resources Conservation Service, experimented with prescribed grazing with goats on two wetland sites that did not contain bog turtles at the time but did show records of occurrence from the 1990s either at or near the sites. After the goats began their work, both sites showed a significant reduction in multiflora rose, with the goats also feeding on red maple saplings. The goats left an obvious browse line at both sites.
Service biologists next decided to try prescribed grazing at a current bog turtle site. Due to the ability of goats to escape enclosures, six-strand high-tensile electric fencing was installed during the winter of 2008. A run-in shelter was added because of the small size of the goats.
With permission from the landowner, the goats were introduced to the wetland site on July 19, 2008. They browsed on multiflora rose, red maple, and Russian olive (Elaeagnus angustifolia), working their way from the upland/wetland edge inward until their removal on September 19. The goats will probably be used for at least another year or two.
Photos were taken at nine monitoring stations approximately every two weeks. Five vegetation plots were established and data characterizing vegetation cover will be collected. If this experiment proves to be effective, goats may be used on other bog turtle wetland sites as a low-impact approach to control unwanted woody trees and invasive plants.
More than 97 percent of bog turtle wetlands occur on private lands, so the recovery of this species will depend heavily on the voluntary assistance of landowners. Since 1997, various habitat restoration techniques have been completed at 17 wetlands on private lands in Maryland totaling more than 150 acres (60 ha).
In addition to the private landowner, partners in the 2008 project included the Fish and Wildlife Service, Natural Resource Conservation Service, and Environmental Defense Fund. The U.S. Department of Agriculture holds a permanent easement for the wetland portion of this property.
For more information on this project, contact Julie Slacum (julie_thompson@ fws.gov; 410-573-4517) at the Service's Chesapeake Bay Field Office in Annapolis, Maryland.
Kathy Reshetiloff, a writer/editor in the Chesapeake Bay Field Office, can be reached at email@example.com or 410-573-4582.
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|Publication:||Endangered Species Update|
|Date:||Jan 1, 2009|
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