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Puritan tiger beetle Listed: 8/7/1990 Status since listing: Declined The Puritan tiger beetle (Cicindela puritana) formerly inhabited sandy water-edge habitats in Vermont, New Hampshire, Massachusetts and Connecticut along the Connecticut River and on the shores of Chesapeake Bay in Maryland [1]. It is currently found in only four locations: on the Connecticut River (Massachusetts and Connecticut) and on the shores of Chesapeake Bay, Maryland (Calvert County and the mouth of the Sassafras River). The species' decline was caused by damming and channelization of rivers, development, and stabilization of riverbanks and shorelines [1]. Twenty-three percent of extirpated sites on the Connecticut River were flooded by dams, 38% were heavily urbanized, and 8% were riprapped and stabilized. Along the entire course of the Connecticut River, only two sites in addition to the occupied sites are considered suitable for beetle reintroductions. While large-scale natural processes remain substantially intact in Chesapeake Bay, the erosive shoreline is being developed rapidly, causing local, state and federal agencies to fund beach stabilization and augmentation programs that destroy tiger beetle habitat. Calvert County has grown by over 300% since 1950 and much of the tiger beetle's habitat has been subdivided and either has been or is likely to be developed. The Connecticut River populations are small but intensively managed. They have increased in size since being placed on the endangered list in 1990. The Chesapeake Bay populations are much larger, but enjoy very little institutionalized habitat protection or management. They have declined substantially since listing and continue to decline as of 2005. CONNECTICUT RIVER: The Puritan tiger beetle formerly occurred in at least 12 populations along the Connecticut River in Vermont, New Hampshire, Massachusetts and Connecticut [1]. It was thought extinct in the region as of about 1939 until a population of 100-200 adults was discovered near Northampton in 1986 [3]. Shortly thereafter, unscrupulous collectors raided the location, taking as many beetles as possible [7]. By the time the species was placed on the endangered list in 1990, the population had declined to about 75 adults [5]. It continued declining to about 25 adults by 1993 [1], but habitat protection efforts prevented the beetle's extinction and kept numbers stable at 25-40 adults between 1997 and 2001 [6]. Beginning in 2000, this population was augmented with beetles from a larger population in Connecticut [3]. These efforts increased the population size to 198 in 2005 -- the largest since its discovery. The Connecticut population occurs downstream in the Cromwell-Portland area. It was discovered in 1989 and consists of three small sites acting as a metapopulation [1]. The population level has fluctuated considerably, but increased from 374 adults in 1991 to 648 in 2005 [6]. Its highest point was 1,072 in 2004. An experimental but failed reintroduction effort was conducted in South Windsor, Connecticut in 1993 [1]. The tiger beetle remains extirpated from the Vermont and New Hampshire sections of the Connecticut River. CHESAPEAKE BAY: The Calvert County population is composed of eight subpopulations, three of which regularly had (until recently) more than 500 adults [2]. Numbers declined sharply from 11,431 censused adults in 1988 to 4,073 in 1990, then fluctuated considerably but without discernable trend between 1990 and 2000, with most years having between 3,400 to 6,200 adults [2, 4]. Numbers steadily declined between 2000 and 2005 to 1,098 adults. The Sassafras River mouth population is composed of eight subpopulations, with the vast majority of beetles occurring at the Grove Point subpopulation [2]. Censused adults increased from 950 in 1989 to 2,755 in 2001, then declined relatively steadily (with the exception of high years in 1995 (1,766) and 1996 (1,821) to 458 in 2005 [2, 4]. The cause of the decline is not well known, but is probably associated with increased vegetation growth (much of it non-native) on the cliff-face, and habitat changes (natural and anthropogenic). The 1993 federal recovery plan calls for: 1) A minimum of six large (500-1000+ adults) populations within habitat that is protected in perpetuity at current sites along both shores of the Chesapeake Bay; 2) protection of sufficient habitat between these populations to support smaller populations, providing an avenue for genetic interchange among large populations and ensuring a stable metapopulation structure; 3) a minimum of three metapopulations, at least two of which are large (500-1000+ adults), maintained (at extant sites) or established within the species’ historical range along the Connecticut River, with the habitat they occupy permanently protected; and 4) an effective and long-term program for site-specific management that is based on an adequate understanding of life-history parameters, human impacts, factors causing decline, population genetics and taxonomy [1]. [1] U.S. Fish and Wildlife Service. 1993. Puritan tiger beetle (Cicindela puritana) recovery plan. Hadley, MA. |
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