Northeastern Naturalist 192 M.A.Ward and J.D. Mays 22001155 NORTHEASTERN NATURALIST 2V2(o1l). :2129,2 N–1o9. 91 Cicindela marginata Fabricius (Carabidae: Cicindelinae) in the Northeastern United States: A Tiger Beetle In Decline? Mark A.Ward1, 2,* and Jonathan D. Mays3, 4 Abstract - We assessed the validity of the reported regional decline of Cicindela marginata (Salt Marsh Tiger Beetle) in the northeastern US by examining data from 3 sources: potential habitat availability maps, author inquiries, and historical and current state records. While the species has apparently experienced decline at a few sites, we contend that existing data do not support the assertion of decline throughout the Northeast. The paucity of systematic surveys, a disproportionate number of northeastern states with comparatively short tidal shorelines, and over-reliance on C. hirticollis (Hairy-necked Tiger Beetle) as a proxy species for C. marginata, have all contributed to the perception of regional decline. Our findings indicate the need for a better understanding of this species’ distribution and abundance. Concerted statewide surveys are needed to assess the current status of decline and to establish a baseline for assessing emerging threats such as sea-level rise due to climate change. Introduction Cicindela marginata Fabricius (Salt Marsh Tiger Beetle), a species restricted to coastal localities, is known in the US from Maine to Florida (Pearson et al. 2006). Adults are found in tidal marshes usually associated with sandy barrier beaches (Leonard and Bell 1999) and have been reported from a variety of microhabitats including salt marshes, tidal flats, backdune marsh strands (where back-beach dunes and salt marsh meet), mouths of tidal rivers and streams, and ocean-side beaches (Dunn 1981, Pearson et al. 2006, Ward and Mays 2014). Cicindela marginata is globally secure (NatureServe 2012), but is considered to be a dwindling species in the northeastern US (Leonard and Bell 1999). In New England, the species has apparently declined significantly (Knisley and Schultz 1997) and has become restricted to a few protected areas (Pearson et al. 2006). Rarity ranks for C. marginata in many northeastern states seem to support the case for regional decline. For example, the species is considered SH (possibly extirpated) in New Hampshire; S1 (critically imperiled) in Rhode Island, Connecticut, and Delaware; and S3 (vulnerable) in New York (NatureServe 2012). There appear to be few historical records of C. marginata in many northeastern states. Sikes (1998) found that historical data for the species in Connecticut 1Research Associate, University of New England, Department of Environmental Studies, Biddeford, ME 04005. 2Current address - 3424 Campus Boulevard NE, Albuquerque, NM 87106. 3Maine Department of Inland Fisheries and Wildlife, Bangor, ME 04401. 4Current address - Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, 1105 SW Williston Road, Gainesville, FL 32601. *Corresponding author - maward@centurylink.net. Manuscript Editor: Christopher M. Heckscher Northeastern Naturalist Vol. 22, No. 1 M.A.Ward and J.D. Mays 2015 193 were limited to a handful of specimens collected prior to 1980. Only 2 historical records exist in Rhode Island, from a single township in 1914 (Leonard and Bell 1999; C. Raithel, Rhode Island Department of Environmental Management, West Kingston, RI, pers. comm.). In New Hampshire, where the species is presumed to have been extirpated, historical records exist from only 2 townships (Dunn 1981, Leonard and Bell 1999). Only 1 historical record exists for Delaware: a specimen collected from an unknown location in 1939 (C. Heckscher, Delaware State University, Dover, DE, pers. comm.). In Maine, the species was documented at only 3 locations prior to 1980 (Ward and Mays 2014). While there are a large number of historical locations in New York, Schlesinger and Novak (2011) explained that the state has fewer records than might be expected. Recent surveys for C. marginata are lacking despite its presumed rarity in several states in the Northeast and the assertions of regional decline. In 2010, we undertook a search for this species in Maine, and found it to be present at all 4 previously known sites and documented the beetle at 8 new locations (Ward and Mays 2014). Our failure to find evidence of decline in Maine prompted us to closely examine the evidence supporting the species’ apparent decline in the Northeast. Methods We sought evidence for the species’ decline in the Northeast from 3 sources. First, we assessed the approximate amount of potential habitat for the species in coastal states from Virginia to Maine by examining tidal shoreline lengths as mapped by the National Oceanic and Atmospheric Administration (NOAA 1975). NOAA tidal shoreline lengths are estimates of shoreline subjected to tidal influence to the head of tide or to a point where tidal waters narrow to a width of 30.48 m (100 ft) and include outer coast, offshore islands, sounds, bays, rivers, and creeks (NOAA 1975). We examined these data to determine the degree to which the species’ statewide vulnerability might be influenced by habitat availability and how that might affect the perception of regional decline. Next, we contacted authors who have asserted decline of the species in the northeastern US to seek clarification on supporting data. Finally, we compiled current and historical site data for each of the northeastern states (Virginia to Maine) by reviewing the scant published data available for the species and attempting to contact knowledgeable persons regarding evidence of decline in their respective states. Results and Discussion An examination of tidal shoreline length along coastal states in the northeastern US revealed that in all 5 states with <1000 km of tidal shoreline, the species was either absent (PA), extirpated (NH), or considered critically imperiled (RI, CT, DE; Table 1). In the 6 states where >1000 km of tidal shoreline exist, the species was considered secure (S5) or apparently secure (S4) in 4 (MA, MD, NJ, VA), vulnerable (S3) in 1 (NY), and not ranked (SNR) in another (ME) (NatureServe 2012). These data suggest to us that C. marginata’s perceived vulnerability in a given state was in part attributable to limited habitat availability (as inferred Northeastern Naturalist 194 M.A.Ward and J.D. Mays 2015 Vol. 22, No. 1 by amount of tidal shoreline). States with limited habitat almost certainly have smaller numbers of suitable sites, and thus fewer beetles. In these states, declines at a small number of sites may imperil or even locally extirpate the species. We believe that the disproportionate number of states in the Northeast with short tidal shorelines has contributed to the perception that decline of the species is a regionwide phenomenon. Responses to our inquiries from authors who have suggested a regional decline for C. marginata further highlighted for us the paucity of historical Table 1. Potential habitat and status of decline for Cicindela marginata Fabricius (Salt Marsh Tiger Beetle) in northeastern Atlantic coastal states. Tidal shoreline length (km) = shoreline of outer coast, offshore islands, sounds, bays, rivers, and creeks is included to head of tide, or to point where tidal waters narrow to a width of 100 feet (NOAA 1975). Tidal State Evidence shoreline rarity Current sites of decline? State length (km) rank State listing Historical sites (reporting year) (# of sites) ME 5597 SNR Special concern 4 (pre-1996)A 12 (2010)A No NH 211 SH Extirpated 2 (pre-1980)B, C 0 (1999)B Yes (2) MA 2445 S4 None 5 (pre-1986)B, C >20 (2012)D No RI 618 S1 Threatened 1–2 (pre-1980)B, E 9 (2012)E No CT 995 S1 Special concern 2–3 (pre-1980)F 5 (2012)F, K Yes (2) 7–8 (pre-1996)F NY 2977 S3 None 22 (pre-1980)G, H 6 (2012)I PossiblyJ NJ 2884 S4 None 13–17(pre-1978)L 2 (2011)M No PA* 95 None 0 0 No DE 613 S1 Special concern 1 (pre-1995) 3 (2002)N Yes (1–2) 5 (pre-2003)N MD 5134 S5 None >10 (pre-1997)O >10 (2013)P No VA 5335 S3S4 None >10 (pre-1997)O >10 (2013)Q No AWard and Mays 2014. BLeonard and Bell 1999. CLaRochelle 1986. DT. Simmons, Natural Heritage and Endangered Species Program, West Boylston, MA, 2012 unpubl. data. EC. Raithel, Rhode Island Department of Environmental Management, West Kingston, RI, 2012 unpubl. data. FSikes 1998. GGordon 1939. HLeonard 1928. IM. Schlesinger, New York Natural Heritage Program, Albany, NY, 2012 unpubl. data. JBlanchard 2006. KL. Saucier, Connecticut Department of Energy and Environmental Protection, Burlington, CT, 2012 unpubl. data. LBoyd 1978. MR. Somes, New Jersey Natural Heritage Program, Robbinsville, NJ, 2013, unpubl. data. NC. Heckscher, Delaware State University, Dover, DE, 2013 unpubl. data. OKnisley and Schultz 1997. PJ. McCann, Maryland Department of Natural Resources, Frostburg, MD, 2013 unpubl. data. QC. Barry Knisley, Department of Biology Randolph-Macon College, Ashland, VA, 2013 unpubl. data. *Species not reported from Pennsylvania. Northeastern Naturalist Vol. 22, No. 1 M.A.Ward and J.D. Mays 2015 195 data available for the species, and underscored the challenges of assessing its regional status with such limited information. Jonathan G. Leonard (University of Vermont, Burlington, VT, pers. comm.) and Ross T. Bell (University of Vermont, Burlington, VT, pers. comm.), co-authors of Tiger Beetles of the Northeast (1999), noted that the reported decline for the C. marginata was based on: (a) its localized extirpation in NH, (b) documented decline for C. hirticollis Say (Hairy-necked Tiger Beetle) in similar habitats, and (c) an assumption that habitat destruction for C. marginata would increase with increasing development pressure. They acknowledged that, since their writing, “habitat destruction may have slowed with protection efforts, and that more localities for C. marginata may have been discovered with greater search effort”. C. Barry Knisley (Randolph-Macon College, Ashland, VA, pers. comm.), suggested that the species’ perceived decline in the Northeast (Knisley and Schultz 1997, Pearson et al. 2006) might be a case of “limited observations indicating it is no longer present where it once was”. Dr. Knisley noted that he has found the species to be common in Maryland and Virginia even at some sites where there is significant human activity. In our compilation of current and historical data for the northeastern US (Table 1), we found relatively little existing evidence of decline. New Hampshire The only northeastern state with strong, documented evidence of decline is New Hampshire (Table 1), where C. marginata is presumed to have been extirpated at the last remaining site in the late 1970s by insecticide-spraying of salt marshes (Dunn 1981, Leonard and Bell 1999). Available data suggest that the species was historically documented from only 2 NH towns (Dunn 1981) and from possibly as few as 2 sites in the state (Dunn 1981, LaRochelle 1986). We did not learn of any surveys undertaken in the last 30 years for this species at coastal sites in New Hampshire. Connecticut In Connecticut, C. marginata was 1 of 6 species that Sikes (1998) targeted for field surveys in compiling a statewide tiger beetle database. The species was historically known from only 2 townships (comprising 2 or possibly 3 sites) prior to 1980, but an additional 5 sites in the state were documented from 1985 to 1990 (Sikes 1998). Sikes revisited each of those 5 additional sites once (from 1996 to 1998) during the likely adult-flight period (Sikes 1998) and found C. marginata at 3 of them, but not at 2 others (Sikes 1998). The species was found at 1 new site by Sikes (1998) and subsequently at another new site in 2005 (L. Saucier, CT Department of Energy and Environmental Protection, Burlington, CT, unpubl. data). Sikes did not visit the historical sites (pre-1980), and no further surveys for the species have been undertaken in Connecticut (L. Saucier, pers. comm.). These data suggest that decline of C. marginata has been documented at most from only 2 locations in Connecticut. Northeastern Naturalist 196 M.A.Ward and J.D. Mays 2015 Vol. 22, No. 1 Delaware Prior to 1995 in Delaware, there was only 1 C. marginata specimen taken from an unknown location in 1939 (University of Delaware Insectary, Newark, DE). That individual was presumed to represent a population from New Castle County. If so, the population has not been relocated (C. Heckscher, pers. comm.) and if extirpated would represent an incidence of decline. Cicindela marginata was documented from 4 additional sites in Delaware during the period 1995–2002. At 1 site where several C. marginata adults were observed in 1995, a recent targeted survey (almost to the day 18 years later in 2013) by A. Dalton of the Delaware Department of Natural Resources and Enivonrmental Control, Dover, DE, failed to relocate the species (C. Heckscher, pers. comm.); this survey work provides the strongest evidence of decline to date for C. marginata in Delaware. New York In New York, C. marginata was not among 8 rare tiger beetle species for which statewide status assessments were recently conducted (Schlesinger and Novak 2011). Based on an examination of 2 historical sources (Gordon 1939, Leonard 1928), M.D. Schlesinger (New York Natural Heritage Program, Albany, NY, pers. comm.) estimated that there were 22 historical locations for this species. Recent records exist from at least 6 New York sites (M.D. Schlesinger, unpubl. data). Blanchard (2006) reported that the species was absent at numerous Long Island locations, including some sites where he had previously detected it, suggesting the possibility of decline at some New York sites. Maine In a concerted survey for this species in Maine in 2010, we found C. marginata at all 4 previously documented locations as well as at 8 new locations; we found no evidence of decline in the state (Ward and Mays 2014). Rhode Island In Rhode Island, the species was known historically from only 1 or 2 sites (La- Rochelle 1986; Leonard and Bell 1999; C. Raithel, pers. comm.). Although recent efforts have revealed 9 new sites in Rhode Island, some of which host fairly large populations (C. Raithel, unpubl. data), the historical sites were not among those recently surveyed; therefore, no evidence of decline exists in that state. Massachusetts Although there has been no concerted survey effort for the species in Massachusetts, there are recent records of C. marginata occurrences at more than 20 sites (T. Simmons, Natural Heritage and Endangered Species Program, West Boylston, MA, unpubl. data). We found no documented evidence of decline in the state. New Jersey There are historical records that document the species at more than a dozen sites in New Jersey (Boyd 1978). Cicindela marginata has been reported recently from Northeastern Naturalist Vol. 22, No. 1 M.A.Ward and J.D. Mays 2015 197 2 of the sites (R. Somes, New Jersey Natural Heritage Program, Robbinsville, NJ, unpubl. data), but no concerted effort has been made to survey historical sites, and no evidence of decline exists in New Jersey. Maryland and Virginia In both Maryland and Virginia, the species is widespread, and past documentation exists from 10 counties in each state (Knisley and Schultz 1997). Although it is not tracked by either state, C. marginata is considered to be common in both Maryland and Virginia, especially in the lower portions of the Chesapeake Bay where there is no evidence of recent decline. The species has been routinely encountered (sometimes in abundance) in Maryland and Virginia during site surveys for the federally threatened C. dorsalis dorsalis Say (Northeastern Beach Tiger Beetle; C. Barry Knisley, pers. comm.; J. McCann, Maryland Department of Natural Resources, Frostburg, MD, pers comm.). Summary The information we gathered from all 3 sources (potential habitat-availability maps, author inquiries, and historical and current records in northeastern states) suggests to us that the case for regional decline of C. marginata may have been overstated. Our compilation of current and historical data resulted in potential evidence for decline at only a small number of locations (5–6) in 3 states (NH, CT, DE) and possibly some locations in a 4th state (NY). Moreover, apparent decline at 3 sites in 2 states (CT, DE) was based on a single visit during the adultflight season. Our efforts to quantify the extent of regional decline of C. marginata were limited by: (1) scant historical data in many states, and (2) insufficient concerted survey effort in most northeastern states. Without improved presence–absence and abundance data, it is impossible to state definitively the extent to which C. marginata has declined in the Northeast. While we acknowledge that the species has experienced decline at a few sites, we contend that existing data do not support the assertion that the beetle has experienced decline throughout the region. Our findings indicate the need for a better understanding of the species’ distribution and abundance. Authors’ past assertions of regional decline for the C. marginata were understandable given the paucity of data available to them. The species’ documented extirpation in New Hampshire may have led to an over-reliance on decline trends for C. hirticollis as a seemingly sympatric coastal species and proxy for C. marginata. Past perception of regional decline was hampered by insufficient data, and we still lack adequate data to decipher definitive trends for the species. Although we found no evidence for decline in 6 northeastern states (ME, MA, RI, NJ, MD, VA), a concerted survey of historically documented sites has only been carried out in 1 of these states (Maine; Ward and Mays 2014). Dedicated search efforts in several northeastern states (ME, RI, CT, DE) where the species is tracked have found C. marginata at previously undocumented sites. Although discovery at new sites may indicate the species is not in decline, it underscores the need for concerted Northeastern Naturalist 198 M.A.Ward and J.D. Mays 2015 Vol. 22, No. 1 statewide surveys to determine current distribution and abundance. Future surveys should include revisits to documented historical sites to assess possible decline as well as visits to sites with potential habitat in order to establish a more complete understanding of current distribution and abundance for the species. Findings from field surveys would help to assess the degree to which ongoing coastal threats may have already caused decline of C. marginata and provide an important baseline for assessing emerging threats such as accelerating sea-level rise. Acknowledgments We are extremely grateful to the many persons who generously responded to our requests to share information on the species: Ross and Joyce Bell, Richard Dearborn, Dave Gumbart, Christopher Heckscher, C. Barry Knisley, Jonathan Leonard, Jim McCann, Bob Nelson, Christopher Raithel, Steve Roble, Matthew Schlesinger, Laura Saucier, Thomas Schultz, Derek Sikes, Tim Simmons, and Robert Somes. Literature Cited Blanchard, O.J. 2006. 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