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Northeastern beach tiger beetle Listed: 8/7/1990 Status since listing: Stable The northeastern beach tiger beetle (Cicindela dorsalis dorsalis) formerly occurred in great swarms along coastal beaches from Cape Cod to New Jersey and along the Chesapeake Bay shoreline [1]. Shoreline development, beach stabilization efforts, and increased recreation, especially off-road vehicles, nearly extirpated it from the Atlantic coast and threaten its existence in Chesapeake Bay. When listed as an endangered species in 1990, it occurred in just two populations in Massachusetts (though only one was known at the time) and in numerous populations along Chesapeake Bay. Since then, the species has increased in number in Massachusetts and New Jersey, declined dramatically in Maryland, and appears to be stable in Virginia. Overall, the beetle's population trend since 1990 is stable, but the trend is dominated by the Virginia population which is orders of magnitude larger than all others combined. Massachusetts. #1) The Northeastern tiger beetle was thought extinct in the Northeast until a population was discovered on Martha's Vineyard in 1990. The population fluctuated significantly, but increased overall between 1990 and 2005 [11]. It declined steadily from 1,787 adults in 1990 to 220 in 1993, spiked back to 1,392 in 1994, then declined steadily again to 268 in 1998. With the exception of 2003, however, it increased every year between 1999 and 2005. The 2005 census documented 2,159 adults. There is a close correlation between the declining periods and severe tropical storms and hurricanes which caused massive erosion of beetle habitat [12]. The storms also created beetle habitat by producing washover fans and blow-outs, many of which have since been recolonized; areas not recolonized were subjected to thousands of off-road vehicle trips annually [12]. #2) A small population of 100 adults was discovered at Horseneck Beach State Reservation/Westport Town Beach in 1994 [5]. The population fluctuated significantly between 1994 and 1996, crashed to just eight adults in 1999 and steadily dwindled to zero in 2005. If not already extirpated, the population is very close to it. #3) 113 larvae were translocated from Martha's Vineyard to the 7,604-acre Monomoy National Wildlife Refuge between 2000 and 2003 [7]. The number of counted adults ranged from 16 to 28 between 2001 and 2005. The presence of adults in 2004 and 2005 despite there being no introductions that year is a promising sign that this experimental reintroduction is working. The beetles use a large overwash backed by dunes that is also an important piping plover nesting area; about 75% of the population occurs in plover protected areas [13]. New Jersey. Formerly extirpated from New Jersey, larvae from Chesapeake Bay were translocated to the northern section of the Sandy Hook Unit of Gateway National Recreation Area between 1994 and 2000 [6]. Emergent adults increased from 55 in 1995 to over 700 in 2000 and 2001, declined to six in 2004 and were not censused in 2005 [4, 6]. The cause of the decline is not known, but a large increase in gull numbers is suspected of increasing predation and disturbance pressure. Additional relocations are planned for 2006 [4]. Maryland. Six major Maryland populations are known along the Chesapeake Bay. The two large eastern shore populations fluctuated greatly in abundance between 1997 and 2005 [8], exhibiting a stable to slightly increased overall trend. The 2005 count was 2,475 at Janes Island and 1,298 at Cedar Island.. The four Calvert County populations declined from an average of 9,257 in 1990-1992, to 3,069 in 1996, and then fluctuated without a trend (usually between 1,000 and 3,000 adults) between 1996 and 2004 [8]. The beetle has disappeared from two of the four sites. Virginia. Virginia populations are distributed along the eastern and western shorelines of Chesapeake Bay. The 1998-1999 to 2004-2005 population trend was relatively stable, fluctuating around 60,000 adults. Eastern shoreline populations increased slightly in recent years: 1999 (32,143 adults), 2002 (33,469), and 2005 (36,201, excluding the newly found Church Neck North population) [8]. The fewest numbers of adults and smaller populations were in the marshier northern third of the peninsula and the largest total numbers and most large populations in the middle section, from Parkers Marsh to Savage Neck [9]. Western shoreline populations increased from 1998 (26,693 adults, 15 populations with >500) to 2001 (33,624 adults, 19 populations with >500) [10]. Following Hurricane Isabel, which caused widespread erosion on the western shore (but less so on the eastern), the population declined to 12,187 adults with only 6 populations >500 in 2004. The population rebounded in 2005 (approximately 19,300), but not yet to pre-hurricane levels [2]. The 1994 federal recovery plan [1] requires that: 1) At least three viable populations have been established and permanently protected in each of four designated Geographic Recovery Areas (GRAs) covering the subspecies’ historical range in the Northeast, with each GRA having one or more sites with large populations (peak count > 500 adults) and sufficient protected habitat for expansion and genetic interchange; 2) At least 26 viable populations distributed throughout all five Chesapeake Bay GRAs are permanently protected; 3) Life history parameters (including population genetics and taxonomy), human impacts, and factors causing decline are understood well enough to provide needed protection and management; and 4) An established, long-term management program exists in all states where the species occurs or is reintroduced. The GRAs are as follows: GRA 1C Coastal Massachusetts and Islands, GRA 2- Rhode Island, Block Island, and Long Island Sound, GRA 3- Long Island, GRA 4- Sandy Hook to Little Egg Inlet, NJ, GRA 5- Calvert County, MD, GRA 6- Tangier Sound, MD, GRA 7- Eastern Shore of Chesapeake Bay, VA, GRA 8- Western Shore of Chesapeake Bay (north of Rappahannock River), VA, GRA 9- Western Shore of Chesapeake Bay (south of Rappahannock River), VA. The major factor limiting recovery in the northeast is the lack of suitable translocation sites [4]. [1] U.S. Fish and Wildlife Service. 1994. Northeastern beach tiger beetle (Cicindela dorsalis dorsalis) recovery plan. Hadley, MA. 45 pp. |
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