The bog turtle, Glyptemys muhlenbergii, is an inhabitant of fens, bogs, and wet meadows that are characterized by substrates of mucky, organic soil that is kept saturated by groundwater discharge. Plant communities associated with bog turtle habitats vary in species composition but are almost always dominated by low-growing grasses (e.g., rice-cut grass, tufted hair grass), sedges (e.g., tussock sedge, spike rush, wool grass), rushes (e.g., soft rush), mosses (e.g., sphagnum), ferns (e.g., royal fern, cinnamon fern, marsh fern, sensitive fern), scattered cattails, and ephemeral and perennial forbs (e.g., New York ironweed, joe-pye weed, blue vervain, turtlehead). Shrub and tree cover in bog turtle habitats is very low, and physical features include spring-derived rivulets, shallow, mucky pools, and abundant hummocks of sedges or moss.

These palm-sized, elusive turtles spend much of their lives hidden in the cool, soft muck that provides them with cover and aids in thermoregulation during hot summer days. Emerging in the spring from subterranean hibernacula, bog turtles spend much of spring and early summer basking on hummocks, matted vegetation, or in open mucky pools and rivulets.

Mating occurs in May and June. Six to eight weeks following copulation gravid females begin their quest for egg-laying sites in drier microhabitats within the soggy marsh, including sedge and moss hummocks, rotted tree stumps, or raised islands of ground that allow for gas exchange in the developing embryos.

Throughout much of the summer bog turtles remain concealed within the dense wetland vegetation, only emerging to bask when cooler late-summer mornings arrive. By mid to late October, bog turtles return to their hibernacula, which is often within the water-washed root systems of woody plants.

Their diet consists of invertebrates, particularly slugs, which are abundant in most bog turtle habitats with preferred plants such as skunk cabbage, jewelweed, and boneset. However, bog turtles will feed on a wide variety of items including carrion, small berries, sedge seeds, young cattail shoots, and duckweed.

The Status of the Bog Turtle in New Jersey
Once abundant throughout New Jersey, bog turtles are now primarily restricted to the remaining rural portions of the state in Sussex, Warren, Hunterdon, and Salem counties. Bog turtles are habitat specialists, relying on abundant groundwater resources, organic soils, diverse herbaceous vegetation, and contiguous tracts of land for dispersal. Intense land-uses such as urbanization or industrial farming destroy bog turtle habitats through direct wetland alteration/destruction and through secondary impacts that affect water quality and water levels.
Bergen, Camden and Middlesex counties are the best of examples of how intense land-use damages bog turtle habitat. According to historic records pre-1970, these counties at one time supported bog turtle populations in most of the watersheds that occur within each county. However, the urbanization of these counties over the past four decades coincided with the local extirpation of bog turtles.

Nevertheless, where bog turtles still occur in New Jersey they appear to be doing well. As of 2001 there were 168 known bog turtle populations (defined by the limits of gene flow amongst individual wetlands supporting bog turtles), making NJ one of the strongholds in the bog turtle’s range. Of the 168 populations, 28 are considered “metapopulations,” defined by a complex of interconnected wetlands that contain two or more bog turtle demes (colonies) and/or suitable habitats.

From the perspective of long-term viability, the metapopulations are the conservation priority because they can facilitate the normal biological dynamics – dispersal, colonization, and gene flow – that keep populations functionally viable. Fragmented or isolated populations, while still important to protect, are vulnerable to random events such as severe floods, disease, and illegal collection, and at risk of becoming genetically impoverished over time.

Bog Turtle Conservation Initiative

The Endangered and Nongame Species Program created and is implementing a comprehensive management initiative to provide long term conservation of the important bog turtle populations in New Jersey. The management initiative consists of four main actions:

• Developing relationships with private landowners that host bog turtles on their land.
• Facilitating the acquisition of sites threatened by adjacent land use activities.
• Performing habitat management and experimenting with new techniques to control and reverse habitat succession and invasive exotic plant proliferation.
• Facilitating long term protection of bog turtle wetlands by working with local communities to implement land use planning changes guided by the Landscape Project.

Landowner Contacts
Since many of the priority bog turtle sites are on private land, the success of any conservation plan depends on the development of relationships with landowners. The landowner contact initiative is well under way. Mostly through personal contacts, landowners learn about bog turtles and the ecological value of their habitats.

The ENSP takes time to walk properties with landowners and address their concerns on a range of wildlife and conservation topics. Good relationships with landowners has created positive habitat management at the best bog turtle sites.

Acquisition
Several priority bog turtle sites are located on properties that are either slated for development or likely to be developed in the near future. These sites have been proposed as priority acquisition sites. The ENSP has created a partnership with government and private land conservation organizations to preserve bog turtle sites. Partners include NJDEP Green Acres Program, the US Fish and Wildlife Service, the Ridge and Valley Conservancy, New Jersey Conservation Foundation, and Natural Lands.

Habitat Management
The majority of bog turtle habitats are in dire need of management and/or restoration. Plant succession by woody species, and invasion by non-native plants (including purple loosestrife, phragmites, multiflora rose, cattail, Japanese stiltgrass, and reed canary grass) are the primary threats to habitat quality, and most of these plants are extremely difficult to control. However, as aggressively as these plants invade, the ENSP is combating these floristic invaders using several methods.

Comprehensive Habitat Management through Grazing
Grazing in bog turtle habitats has been demonstrated to retard natural succession, control invasion by fast-growing invasive plants, augment hydrological regimes by reducing above-ground vegetative matter and breaking up peat accumulation, create microhabitats for bog turtles in the form of footprints, and encourage the growth of hummocky vegetation that bog turtles use for nesting (Herman 1999). In the Kittatinny Valley of Sussex and Warren counties, 107 of 108 bog turtle sites have been managed with grazing. It has been theorized that livestock are the contemporary analogs of the elk, bison, and mastodons that grazed pre-colonial fens and swamps (Lee and Norden 1996).

With funding from the Natural Resources Conservation Service‘s Wildlife Habitat Improvement Program (WHIP) and the U.S. Fish and Wildlife Service‘s Partners for Wildlife Program, in 1998 the ENSP began introducing sheep, goats, and cattle to bog turtle habitats that are heavily infested by invasive plants. A review of this project is contained in Restoring Wetland Habitats With Cows and Other Livestock, published in Conservation Biology In Practice • Spring 2001/Vol.2 No.2.

Woody Vegetation Control
The growth of woody vegetation will change bog turtle habitat for the worse over time, so biologists use several methods to remove and control tree growth. The frill methodology controls unwanted trees, primarily red maples (Acer rubrum), by scoring the bark with a machete and spraying the wound with a 80% solution of Rodeo. The herbicide is necessary for controlling species such as red maples, because simple cutting or girdling these trees will result in transforming each tree into a multi-stemmed plant that is capable of producing more shade than the original tree.

Cutting can be an effective management method but it is both labor intensive and requires annual management, which is not feasible given the vast number of acreage that biologists are working to maintain. To date, herbicidal woody vegetation management has been effectively used at over 40 bog turtle sites to kill thousands of woody plants, including red maple, alder, arrowwood, willow, poison sumac, and multiflora rose.

Purple Loosestrife Control
Through a partnership with the New Jersey Department of Agriculture‘s Beneficial Insect Lab, Gallerucella pusilla, a natural grazer of the invasive European wetland plant, purple loosestrife (Lythrum salicaria), has been released at 17 bog turtle sites since 1998. It is estimated to take three to five seasons for beetles to build up a population large enough to impact the purple loosestrife population at a site.

The ENSP and Department of Agriculture entomologists will monitor the beetle’s progress over the next several years. Funding for the purchase of beetles has been made possible through the Natural Resources Conservation Service‘s Wildlife Habitat Improvement Program (WHIP) and the U.S. Fish and Wildlife Service‘s Partners for Wildlife Program.

Protecting Bog Turtles with the Landscape Project

The primary objective of the ENSP’s Landscape Project is to preserve functioning metapopulations of rare wildlife species through preserving core habitats and critical connecting corridors. Landscape Project GIS generated mapping products identify critical habitats and habitats that should be protected and/or acquired to provide long term preservation of functional metapopulations. Landscape Project mapping products are widely available and are used to guide the regulatory and public planning processes to support land-use decisions compatible with the conservation of bog turtles and other wildlife populations.

The migratory corridors between bog turtle colonies have suffered loss and conversion of habitat to make them unsuitable. The CHANJ Project – Connecting Habitat Across New Jersey – takes aim at this problem. CHANJ mapping identifies important connections between land parcels that, if preserved and suitably managed, make wildlife movement possible. Safe wildlife corridors consist of habitat that many different types of animals can move through, and for bog turtles, that means stream and wetland corridors that must pass under roadways. CHANJ mapping is available on the DEP website.

Fortunately, where functioning metapopulations still exist, most appear to be safe from further fragmentation due to a combination of wetland protection regulations and federal, municipal, Non-Governmental Organization and state ownership. A large percentage of New Jersey’s landscape has historically been wetland habitat.

Since 1987, when the New Jersey Freshwater Wetlands Protection Act was enacted, many large wetland complexes have been protected from development and primary impacts. Additionally, large contiguous tracts of wetlands have been acquired as public open space within the last 20 years. Consequently, these large wetland systems support a majority of the extant bog turtle metapopulations.

Bog turtle habitats within these wetlands may represent only a small fraction of the total wetland size (habitats are usually ~2 acre seepage fens along the periphery of 100+ acre bottomland swamps). However, these large systems can easily facilitate movement between habitats, and they offer the potential for creation of additional habitat in the future through successional dynamics.

Provided our society and our government maintain a conservation ethic and continue to enforce wetlands and endangered species regulations these large metapopulations are safe from fragmentation and primary impacts. Developable land in and around individual bog turtle sites within metapopulations has been identified as priority acquisition sites. The acquisition of corridors may not be necessary since most corridors exist within large, protected wetland complexes for the most part can be adequately protected through wetland regulations.

Conclusion
We face many challenges as we endeavor to ensure the long-term preservation of bog turtle populations in New Jersey. Fortunately, we still have a significant amount of suitable habitat that still supports relatively large metapopulations of bog turtles. Also, we have made considerable progress in identifying conservation needs and priorities.
Conservation initiatives are also well under way and show promise for preserving and managing habitats into the future. The biggest challenge may be accomplishing enough land preservation and management in a timely enough fashion to stem or reverse the trend of disappearing and degrading bog turtle habitats in a dynamic and rapidly changing landscape.

Future trends in development, growth, open space conservation and land use planning and regulation may ultimately determine whether or not we are successful in our endeavor. However, the ENSP has made great strides in reversing the damaging effects of habitat degradation through active management of habitats. If we can continue on the established pace we should be able to successfully conserve at least a portion of our large functioning bog turtle populations.