The Delicate Balance of Saving Homes and Preventing Extinction

by Julie Thompson Slacum

Massive cliffs dominate the shoreline of the Chesapeake Bay in Calvert County, Maryland. These rare, geologic formations developed 10 to 20 million years ago, and as the cliffs erode, the remains of prehistoric species once entombed in the rock are exposed. From the top of the cliff, the views are expansive and the sandy beaches below attract fossil hunters, sunbathers, and swimmers, creating an attractive location for waterfront living.

The cliffs have weathered naturally over hundreds of years, providing much of the sand on the beaches below. Erosion rates of the cliffs vary, but often are very high at both the bottom of the cliff and upper cliff collapses. The federally threatened and state endangered Puritan tiger beetle (Cincindela puritana) undergoes its entire life cycle on or near these cliffs. The beetle requires some erosion to maintain unvegetated habitat needed for its larva. Adult beetles feed and mate on the beach below the cliff.

While these conditions are ideal for the Puritan tiger beetle, they are problematic for homeowners in the area. Residential areas planned in the 1950s underestimated erosion rates and established lots that are presently seen as unnervingly close to the cliff's edge. While County regulations now require greater setbacks for future development, some of the existing homes are vulnerable to collapse from the top of the cliff. However, measures to control erosion – desired by many property owners – pose a major threat to the Puritan tiger beetle, which lives at various locations along the shoreline. Traditional shoreline erosion control structures, such as bulkheads and revetments, replace the beach habitat used by adult beetles, and over time, the cliff habitat is lost.

The insect's entire range includes two small populations along the Connecticut River—one in Massachusetts, another in Connecticut, and two meta-populations along the Chesapeake Bay. The largest Maryland meta-population occurs in Calvert County on the western shore of the Chesapeake Bay, and the second – a smaller meta-population – occurs along the mouth of the Sassafras River in Cecil and Kent Counties along the eastern shore.

The species' recovery plan sets specific recovery criteria protecting at least six large subpopulations – with 500 to 1,000 adults or more – and their habitats at current sites along both shores of the Chesapeake Bay. Additionally, there must be sufficient habitat protected between these larger populations to maintain connectivity. Three large subpopulations are currently protected by the state.

A population viability analysis conducted for the Puritan tiger beetle in 2005 concluded that, in order to safeguard the beetle from the risk of extinction, populations must be maintained on both private and public lands. Based on the status of the species, the U.S. Fish and Wildlife Service (Service) could not permit projects that proposed building stone revetments at the base of the cliff to continue, and instead recommended other shoreline erosion control measures such as off-shore breakwaters and reef balls that would minimize impacts on the Puritan tiger beetle and its habitat.

A second population viability analysis conducted in 2010, which considered more recent monitoring data and addressed a different set of management strategies, found that maintaining populations on private land was still critical for the species survival, however the overall risk of extinction was now lower, the incidental loss of some beetles at sites where cliff stabilization projects are underway would not devastate the species.

In February 2010, an Interagency Steering Committee, with members from the Service, Maryland Department of Natural Resources (MDNR), Maryland Department of the Environment, U.S. Army Corps of Engineers, Maryland Emergency Management Agency, and Calvert County, was established and charged with developing recommendations to address the impact of shoreline erosion on houses located near the eroding cliffs and measures to simultaneously prevent the beetle's extinction. The work of this interagency group has made substantial progress in meeting the needs of landowners while promoting the species' recovery.

A puritan tiger beetle Habitat Conservation Program developed by the MDNR has also helped assure the species' long-term survival by requiring an Applicant to pay if an activity would result in the incidental loss or harm of the Puritan tiger beetle. Money from this fee will be used to protect or restore Puritan tiger beetle habitat.

In 2011, MDNR received a $2.4 million dollar Section 6 Land Acquisition Grant from the Service to conserve Puritan tiger beetle habitat on two properties in Cecil County, and four more in Calvert County—totaling over 400 acres (160 hectares). These land purchases will help ensure the protection of five large Puritan tiger beetle subpopulations, moving the species closer to a recovery goal of six large, self-sustainable subpopulations along both shores of the Chesapeake Bay.

Additionally, Calvert County recently received funding through the FEMA Hazard Mitigation Program to purchase and demolish 10 houses located along the cliff's edge. These buy-outs will ensure the protection of areas providing continuity of habitat between two Puritan tiger beetle subpopulations, while also providing management flexibility to MDNR and the Service in dealing with revetment projects and cliff grading in these communities. Future easements will be targeted on the eastern shore to achieve protection of the six, large subpopulations needed to meet the primary recovery criterion for the Puritan tiger beetle.

 

Julie Thompson Slacum, Division Chief of Strategic Resource Conservation at the Service's Chesapeake Bay Field Office, can be reached at julie_thompson@fws.gov or 410-573-4595.