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LOGGERHEAD SEA TURTLE LATE NESTING ECOLOGY IN VIRGINIA BEACH, VIRGINIA
Citation:
Cross, C L., J. B. Gallegos, AND F. G. James. LOGGERHEAD SEA TURTLE LATE NESTING ECOLOGY IN VIRGINIA BEACH, VIRGINIA. BANISTERIA 17:52-55, (2001).
Impact/Purpose:
The primary objectives of this research are to:
Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;
Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;
Develop and validate multivariate models based on quantification studies;
Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;
Complete an initial draft (potentially web based) of a national landscape condition assessment.
This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.
Description:
T'he.loggerhead sea turtle (Caretta came is the only recurrent nesting species of sea turtle in southeastern Virginia (Lutcavage & Musick, 1985; Dodd, 1988). Inasmuch as the loggerhead is a federally threatened species, the opportunity to gather data on its nesting ecology is important for establishing appropriate management strategies. Loggerhead females deposit eggs on a 2-4 year cycle, and produce an average of 1-7 nests in any one breeding season (Ehrhart, 1979; Dodd, 1988; Ernst et al., 1994). Nesting in southeastern Virginia generally occurs ftm late May through July, with an occasional nest produced in August. Data from other locations in the southeastern United States indicate that eggs incubate for an average of 60-65 days (range .= 59-78) in natural and transplanted nests (Ernst et al., 1994), and from 70-85 days in hatchery-reared nests (Mrosovsky & Yntema, 1980; Blanck & Sawyer, 1981).
Temperature-dependent sex determination in logger- heads is well documented (Mrosovsky & Yntema, 1980; Standora & Spotila, 1985; Mrosovsky & Provancha, 1989, 1992). Studies of loggerheads in Florida by Mrosovsky & Provancha (1,989, 1992) suggest that hatchling ratios are strongly female-biased, and Georgia and South Carolina populations produce female-biased hatchlings (Mrosovsky et al., 1984). Pivotal incubation temperatures are 29-30 C; males are produced at cooler temperatures and females at warmer temperatures (Nlrosovsky & Provancha, 1992). Given the generally cooler temperatures found in northern climates, it is possible that loggerhead nests in southeastern Virginia (where mean sand temperatures are approximately 27-28 C) are a source of male hatchlings (DeGroot & Shaw, 1993).
Data on loggerhead nesting ecology on the beaches of Back Bay National Wildlife Refuge (BBNWR), Virginia Beach, Virginia and adjacent beaches immediately north and south of BBNWR have been gathered since 1970. Beginning in 1993, funding from the U. S. Army Corps of Engineers, Norfolk, Virginia, has provided salaries for trained U. S. Fish and Wildlife Service personnel at BBNWR to conduct daily patrols along a 16-24 km stretch of beach from May through August.