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INVENTORY OF AMPHIBIANS AND REPTILES OF COLONIAL NATIONAL HISTORICAL
PARK
Technical Report NPS/NERCHAL/NRTR-2005/006
Joseph C. Mitchell, Ph. D.
Department of Biology
University of Richmond
Richmond, VA 23173
May 2005
U.S. Department of the Interior
National Park Service
Northeast Region
Philadelphia, Pennsylvania
___________________________________
Executive Summary
An inventory was conducted at Colonial National Historical Park (COLO) from 2001 to 2003, to 1) document 90% of the amphibians (frogs, salamanders) and reptiles (turtles, lizards, snakes) of COLO, James City, York, and Surry counties, 2) describe their associated habitats, and 3) provide park staff with conservation and management recommendations. Survey methods included visual encounter surveys, audio surveys, and road surveys; dipnets, minnow traps, and turtle traps were also used.
Sixteen species of frogs, 14 salamander species, 10 turtle species, seven lizard species, and 19 snake species were expected to occur at COLO based on known distribution patterns in published literature. The proportion of species documented during this inventory, based on the expected species list, was 88% for frogs, 79% for salamanders, 100% for turtles, 86% for lizards, and 58% for snakes. Total success for amphibians was 83% of expected species, and 72% for reptiles. These success levels are reasonable based on similar inventories conducted elsewhere in Virginia, and sampling limitations caused by the drought conditions that prevailed during the first two years of the study.
Nine habitat types used by amphibians and reptiles at COLO were described from the field notes obtained during this inventory, and include beach, grassland, marsh, mixed hardwoods and pine, mixed hardwoods, mixed pine, impoundments, swamp, and stream. All habitats surveyed support multiple species, and most species use both aquatic and terrestrial habitat types. Habitats that support relatively unique assemblages include hardwood forests (e.g., on Jamestown Island near the entrance gate to the loop road), tidal marshes, seasonal ponds, springs and seepages, and freshwater sources on Jamestown Island. Only two species are habitat-specific, the Two-toed Amphiuma (Amphiuma means) found in ponds, and the Diamond-backed Terrapin (Malaclemys terrapin) in estuarine marshes. Streamside salamanders (Desmognathus, Eurycea spp.) constitute another relatively unique assemblage that inhabit springs and associated wet areas. One state-threatened species, Mabee's Salamander (Ambystoma mabeei), was encountered during this survey.
Some habitats are important for species persistence and should be monitored for the presence/absence of amphibians and reptiles. These include seasonal ponds at Yorktown, mature hardwoods with their small ephemeral wetlands on Jamestown Island, and springs and seepages on the York-James peninsula. The combination of habitat types used by amphibians and reptiles at COLO, including Jamestown Island, should be viewed as a matrix of habitats imbedded within the landscape rather than as separate habitat types, and should be protected as such.
Although this study documented less than 90% of the expected number of species for several groups, there are opportunities to register additional species. This can be accomplished in two ways by park staff: routine accumulation of digital photographs of road-kills or live amphibians and reptiles encountered with appropriate documentation appended to the digital image, and the use of natural history (animal) sighting cards filled out by knowledgeable visitors. Verification of new species records should be confirmed by a herpetologist.
Recommendations
for COLO resource management include:
(1) conducting regular population status surveys of the state-threatened
Mabee's Salamander and monitoring surrounding housing developments that
could alter the hydrology of seasonal ponds supporting this species.
(2) Conduct additional inventory work on species such as the fully aquatic
Two-toed Amphiuma, streamside salamanders and the Northern Diamond-backed
Terrapin that are limited to one or a small number of unique habitat
types in the park, in order to better understand their abundance and
distributions within these habitats.
(3) Conduct additional species documentation work on snakes found at
COLO. Further work to document snake species at COLO should include
the use of coverboards as part of its sampling plan.
(4) One of the more unique habitats found within COLO contains several
of the Grafton Seasonal Ponds complex within its boundaries (Van Alstine
et al. 2001). The area in Yorktown containing these unique habitats
should be viewed as an important matrix of aquatic and terrestrial habitats
supporting many amphibian and reptile species in the park. These seasonal
ponds must be considered key habitats for protection (Semlitsch and
Jensen 2001) along with their surrounding terrestrial habitats preserved
as buffer zones.
(5) Specific habitats should be monitored on a regular basis at COLO
for the occurrence and persistence of amphibians and reptiles, including
seasonal ponds in Yorktown, mature hardwoods with their small ephemeral
wetlands on Jamestown Island, and springs and seepages in the York-James
peninsula.
(6) Logs and snags marked for removal on Jamestown Island
showed that six species were using this micro-habitat for protection.
Removal of such habitat has direct impact on these and other amphibian
and reptile species and halting the removal of such forest debris should
be considered.
(7) A comprehensive natural habitat management plan for the conservation
of native species and their habitats should be developed for Jamestown
Island.
(9) Educational material should be developed on the ecology, flora and
fauna, and their interactions with human history at Jamestown and Yorktown.
(10) Amphibian, reptile, and other vertebrate mortality rates and distribution
along the Colonial Parkway should be determined, and further conservation
and management options considered.
(11) Park raccoon populations should
be monitored in relation to primary turtle nesting sites, and population
control measures considered to protect the turtle nests.
(12) Develop a comprehensive natural habitat management plan to conserve
amphibians and reptiles at COLO.
___________________________
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