Detailed project information for Study Plan Number 02076

Branch :	Aquatic Ecology Branch
Study Plan Number :	02076
Study Title :	Assessment of Ambystomid salamander populations and their breeding habitats in Delaware Water Gap National Recreation Area
Starting Date :	10/01/2000
Completion Date :	12/31/2003
Principal Investigator(s) :	Snyder, Craig; Young, John A.; King, Timothy L.; Spidle, Adrian
Primary PI :	Snyder, Craig
Telephone Number :	(304) 724-4468
Email Address :	craig_snyder@usgs.gov
SIS Number :	5004356
Primary Program Element :	Fisheries and Aquatic Resources
Second Program Element :	Wildlife and Terrestrial Resources
Status :	Completed
Abstract :	BACKGROUND Amphibians are integral components of North American wetland and forest ecosystems. In terms of diversity, amphibians represent approximately 12.5% of the total terrestrial vertebrate species in North America (Banks et al. 1987), and the Appalachian Highlands in eastern North America support a particularly high number of endemic amphibian species (Bury et al. 1995). In addition, amphibians frequently comprise the largest fraction of vertebrate biomass. For example, salamander biomass in a northern hardwood ecosystem in New Hampshire was more than twice that of the bird community and nearly equal to that of small mammals (Burton and Likens 1975), while in southern Appalachian forests salamander biomass may exceed that of all other vertebrates combined (Hairston 1987). Concern over amphibians has heightened in recent years due to increasing evidence of global and regional population declines, range reductions, and extinctions (Wyman 1990). In the United States, about one-third of the amphibians species are suspected of having declines (Bury et al. 1995). Moreover, these declines are not limited to highly degraded areas. Significant losses of amphibians have been documented in relatively pristine areas such as National Parks that generally lack obvious habitat loss or alteration (Blaustein and Wake 1990). Based on these trends, the Secretary of Interior recently announced (April, 1998) a new, USGS-led initiative on amphibians designed to provide a comprehensive nationwide assessment of the current status of amphibian populations and to determine the causes of declines. Many amphibians, such as ambystomid salamanders, have a biphasic life-history pattern. Adults migrate to breeding ponds, deposit eggs, and return to terrestrial habitats (Duellman and Trueb 1986). The eggs hatch as aquatic larvae that remain in the water for various amounts of time depending on hydroperiod, thermal regime, predation, competition, and other related factors (Dodd and Cade 1998). As a result, these pond-breeding amphibians are widely believed to be sensitive indicators of overall ecosystem health because they require undegraded habitats in both terrestrial and aquatic environments (Bury 1988, Vitt et al. 1990, Welsh and Ollivier 1998). Within the nearly 70,000 acres of the Delaware Water Gap National Recreation Area (DEWA) are hundreds of wetlands, vernal ponds, beaver ponds and impoundments that provide potential amphibian habitat. Eight amphibian species have been documented in DEWA that are classified as "species of special concern" by the states of Pennsylvania or New Jersey (Stein 1983). Four of these species are pond-breeding ambystomid salamanders: Jefferson salamander (Ambystoma jeffersonianum), silvery salamander (A. platineum), spotted salamander (A. maculatum), and marbled salamander (A. opacum). Because the counties surrounding DEWA have been among the fastest growing counties in Pennsylvania and New Jersey for more than a decade (documented by state statistics), there is growing concern that amphibian populations may be declining in many surrounding areas as a result of human developments. Activities within DEWA may also threaten these salamander populations. Currently, DEWA actively manages beaver and has plans to manage over 120 man-made impoundments within the park. These actions influence the size, number, and distribution of ponds that may be important breeding habitats for ambystomid salamander populations. In addition, DEWA supports a network of roads and trails that may influence migratory behavior and success by fragmenting dispersal corridors. There are currently plans to expand trails and roads in the park. Finally, DEWA leases more than 3,000 acres for agriculture under special permits, and has recently initiated special riparian conservation and restoration measures. Information regarding the distribution, abundance and habitat requirements of these salamander species within DEWA is needed as soon as possible to inform these and other types of management decisions. Pond-breeding amphibian populations are widely believed to have metapopulation structure (i.e., groups of subpopulations linked together by dispersal of individuals and gene flow). One of the implications of metapopulation structure is that the importance of individual ponds to the persistence of the overall population depends on the sources and direction of gene flow in addition to the production of recruits from individual ponds (Fahrig and Merriam 1985). In the absence of long-term data on movement and gene flow, managers are forced to rely entirely on pond use (e.g., number of egg masses) to draw inferences about critical breeding habitat. However, the extent to which a pond is used may not correlate with their importance to the larger population. For example, pond utilization may be high in a large numbers of ponds that are clumped in one area of the landscape. Elimination of any one of those ponds may have little impact on the larger metapopulation despite the high levels of pond use. Likewise, an isolated pond that is used for breeding by a relatively small number of individuals may be disproportionately important to the larger metapopulation because it’s existence ensures gene flow to otherwise isolated sub-populations. Thus, in order to assess the status of pond-breeding amphibian populations and their critical breeding habitat requires information on 1) the distribution and abundance of potential breeding ponds, 2) pond-specific estimates of recruitment, and 3) measures of gene flow among ponds. Despite concerns over ambystomid salamanders and the potential threats to their habitat, there have been no comprehensive amphibian surveys or research studies in the park. Until this past year, only about 10 locations that support one or more of these species had been identified within DEWA (Stein, 1978, Stein 1983). This past spring, the WCS surveyed 144 ponds in DEWA and identified 74 additional sites where ambystomids breed (David Brotherton, unpublished data). The lack of information regarding ambystomid salamander distribution, abundance, and habitat requirements precludes effective protection of these populations. OBJECTIVES The objectives of the project are to document the population status, critical breeding habitats, and genetic structure of ambystomid salamanders in DEWA. The information will be used by DEWA to predict the consequences of landscape changes resulting from DEWA management actions or increased development outside the park. COMPLETED STUDY INFO: PUBLICATIONS Julian, J. T., Snyder, C. D., Young, J. A., and others. 2003. Landscape influences on ambystomatid salamander populations in the Delaware Water Gap National Recreation Area: Open File Report (U. S. Geological Survey), v. 01-406, 118 pp Julian, S. E., and King, T. L. 2003. Novel tetranucleotide microsatellite DNA markers for the wood frog, Rana sylvatica: Molecular Ecology Notes 3: 256-258. Julian, S. E., King, T. L., and Savage, K. 2003. Isolation and characterization of novel tetranucleotide microsatellite DNA markers for the spotted salamander, Ambystoma maculatum: Molecular Ecology Notes 3: 7-9. Julian, S. E., King, T. L., and Savage, W. K. 2003. Novel Jefferson salmander, Ambystoma jeffersonianum, microsatellite DNA markers detect population structure and hybrid complexes: Molecular Ecology Notes 3: 95-97. Julian, J.T., C.D. Snyder, and J.A. Young. 2006. The use of artificial impoundments by two amphibian species in the Delaware Water Gap National Recreation Area, USA. In press: Northeastern Naturalist. Snyder, C. D., J. T. Julian, J. A. Young, and T. L. King. 2004. Assessment of Ambystomatid salamander populations and their breeding habitats in Delaware Water Gap National Recreation Area. Final Report submitted to the National Park Service. 51pp. POSTER King, T.L., S. Julian, J. Petranka, and C. Smith. 2004. Identification of population structure and metapopulation extent in Ambystoma maculatum and Rana sylvatica inhabiting vernal pools in selected national parks: Implications for conservation strategies. Poster presentation, American Society of Ichthyologists and Herpetologists, May 26-31, 2004. OUTREACH Currently, the staff of the NPS Eastern Rivers and Mountains network is using updated maps of wetland locations developed in this study in as an important map layer in their vital signs monitoring program. Contact is Dr. Matt Marshall, Eastern Rivers and Mountains Network Coordinator, 204C Ferguson Building, Penn State University, University Park, PA 16802. Phone: 814-863-0134. PRESENTATIONS King, T. L., S. Julian, J. Petranka and D. Smith. Identification and population structure of Ambystoma maculatum and Rana sylvatica in Delaware Water Gap National Recreation Area. USGS Amphibian Research and Monitoring Initiative Symposium, Norman, OK Young, J. A., J. T. Julian, J.W. Jones, C. D. Snyder, and C. W. Wright. Potential of LiDAR intensity data to support characterization of amphibian breeding habitats. Presented at Silviscan: LiDAR Applications in Forest Assessment and Inventory Conference, Blacksburg, VA, September 29-October 1, 2005.
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