Detailed Research Information

Detailed project information for
Study Plan Number 02069-10

Branch : Aquatic Ecology Branch

Study Plan Number : 02069-10

Study Title : Identification of Population Structure, Metapopulation Extent, and Evoluntarily Significant Lineages in the Spotted Turtle: Implications for Restoration

Starting Date : 05/01/2002

Completion Date : 09/30/2007

Principal Investigator(s) : King, Timothy L.

Primary PI : King, Timothy L.

Telephone Number : (304) 724-4450

Email Address : tlking@usgs.gov

SIS Number :

Primary Program Element :

Second Program Element :

Status : Active

Abstract : BACKGROUND
Aquatic habitat is disappearing at an unprecedented pace as a consequence of human population expansion (Erwin 1991). Perhaps no habitat (and its associated flora and fauna) illustrates this trend more profoundly than U.S. wetland areas. Bogs and fens support a wealth of rare and unique life forms. These wetland habitats are being destroyed and degraded at an accelerating rate as a direct and indirect effect of urban sprawl. At least one-third of the threatened and endangered species of the United States reside in wetland areas (Murdock 1994). The spotted turtle, Clemmys guttata, a small freshwater species that prefers shallow spring-fed pools with a bottom substrate of soft mud and rock anchored by low grasses and sedges, clearly illustrates the negative impacts of wetland loss and degradation. The range of the spotted turtle is distributed along the eastern seaboard from Atlantic Canada to Florida, and a possibly disjunct set of populations around the shores of the Laurentian Great Lakes. Declines have been documented in the majority of spotted turtle populations throughout this range, often attributed to habitat fragmentation (e.g., highway construction, residential development), drainage of wetlands, plant succession, and pollution from stormwater discharge. In addition, some populations are extremely localized and have been extirpated by over-collecting to supply the illegal pet trade. Spotted turtles are protected at the state level nearly throughout their range, but continue to decline.

Effective conservation and restoration plans require clearly definable units of management. Spotted turtle management units are currently defined as metapopulations consisting of contiguous wetlands along stream corridors. The principal processes in metapopulation dynamics are extirpation of local subpopulations followed by migration from larger subpopulations and recolonization of regions vacant due to extirpation (Hanski and Gilpin 1997). How these processes affect population dynamics and evolution within subpopulations and across the entire metapopulation is a key question for managers. Environmental patchiness forces species to be structured into hierarchical systems of local populations within which conspecifics are more likely to interact than with across other systems of populations. Isolation, however, is usually not complete and since most organisms have some power of dispersal, members of a local population have a low but positive probability of interaction with individuals from other localities (Weins 1997). Demographic and genetic dynamics will be influenced by the rate of migration among systems of populations as well as local birth and death rates. No genetic information exists on population structure, levels of gene flow, or relatedness of any geographic population of spotted turtles.

A thorough understanding of the evolutionary relationships (i.e., levels of gene exchange) among geographically proximate and distal populations is required to develop management strategies for maintaining evolutionarily significant spotted turtle lineages to ensure long-term population stability and to reduce the need for further protection through the regulatory process at the federal level. Techniques from molecular biology have achieved an important place in contemporary conservation biology as robust tools to identify reproductive isolation among populations, delineate management units and allow assessment of conservation priorities from an evolutionary perspective. Codominant genetic markers with Mendelian inheritance will allow full assessment of population structure, gene flow, kinship, introgression, hybridization and speciation.

The development of tandemly repeated DNA simple sequence motif markers, or microsatellites (Tautz 1989; Queller et al. 1993), provides an ideal tool to investigate the degree of relatedness among species exhibiting small effective population sizes because of the hyper-polymorphism observed. Although the reason for the ubiquitous distribution of microsatellites throughout eukaryotic genomes has not been resolved (Tautz 1989), they have been lauded as the most useful class of nuclear marker available (Queller et al. 1993) due to their hypervariability and ease of sampling. Amplification of microsatellites using the Polymerase Chain Reaction (PCR) allows the survey of a large number of markers in DNA collected from a minimally invasive tissue sample. Sequence homology of regions flanking the microsatellite DNA marker has also permitted use of these markers in closely related species (Schlötter et al. 1991; Gotelli et al. 1994; Scribner et al. 1996; May et al. 1997). Microsatellite DNA markers have been remarkably useful in identification of recently diverged lineages in the bog turtle (Clemmys muhlenbergii, King et al. in preparation), a close relative of the spotted turtle.

This proposed research addresses high priority needs at the agency, inter-agency, and programmatic levels by: 1) working with others (e.g., state agencies) to determine the population structure and evolutionary (systematic) relationships among important biological resources (BRD mission); 2) addressing needs of other Department of Interior agencies such as providing information on geographic population structure and critical habitat (USFWS) and development of new techniques for systematic assessment of wildlife species (USFWS, BRD); and 3) providing information to develop strategies for maintaining evolutionary lineages that will ensure long-term population stability and reduce the likelihood of requiring protection through federal regulatory processes (BRD).
OBJECTIVES
Habitats in wetland areas used by humans occur as sharply defined blocks or fragments, and the patchwork nature of the landscape mosaic is especially evident in such environments. “Metapopulations” have been defined in various ways, but generally, a metapopulation is spatially subdivided into a series of local (patch) populations. The classical view emphasizes a balance between extirpation and recolonization of local populations that enables long-term persistence of the metapopulation (Wiens 1997). In reality, the local populations of a metapopulation occur in habitat patches that are immersed in a complex mosaic of other habitat patches, corridors and boundaries. The most obvious effects of this landscape structure are on individual movement patterns among patches and, consequently, on patch-recolonization probabilities. Clearly, individual movement and gene flow is the most important unifying element in both metapopulation dynamics and landscape ecology (Saunders et al. 1991, Wiens 1992).

Thus, the objectives of this research initiative are to work with state resource management agencies to:

1) adapt a suite of microsatellite DNA markers developed for use in the bog turtle for application to studies of the spotted turtle where unique multilocus genotypes will be generated for each individual surveyed in this study;

2) delineate management units (i.e., metapopulation extent) and evolutionarily significant lineages among geographic populations of spotted turtles collected throughout the species range;

3) provide a highly successful predictive model to assign individual spotted turtles of unknown origin to their natal geographic population (i.e., for law enforcement purposes); and

4) promptly report the management implications of each aspect of this research to all the state and federal stakeholders.

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Branch :	Aquatic Ecology Branch
Study Plan Number :	02069-10
Study Title :	Identification of Population Structure, Metapopulation Extent, and Evoluntarily Significant Lineages in the Spotted Turtle: Implications for Restoration
Starting Date :	05/01/2002
Completion Date :	09/30/2007
Principal Investigator(s) :	King, Timothy L.
Primary PI :	King, Timothy L.
Telephone Number :	(304) 724-4450
Email Address :	tlking@usgs.gov
SIS Number :
Primary Program Element :
Second Program Element :
Status :	Active
Abstract :	BACKGROUND Aquatic habitat is disappearing at an unprecedented pace as a consequence of human population expansion (Erwin 1991). Perhaps no habitat (and its associated flora and fauna) illustrates this trend more profoundly than U.S. wetland areas. Bogs and fens support a wealth of rare and unique life forms. These wetland habitats are being destroyed and degraded at an accelerating rate as a direct and indirect effect of urban sprawl. At least one-third of the threatened and endangered species of the United States reside in wetland areas (Murdock 1994). The spotted turtle, Clemmys guttata, a small freshwater species that prefers shallow spring-fed pools with a bottom substrate of soft mud and rock anchored by low grasses and sedges, clearly illustrates the negative impacts of wetland loss and degradation. The range of the spotted turtle is distributed along the eastern seaboard from Atlantic Canada to Florida, and a possibly disjunct set of populations around the shores of the Laurentian Great Lakes. Declines have been documented in the majority of spotted turtle populations throughout this range, often attributed to habitat fragmentation (e.g., highway construction, residential development), drainage of wetlands, plant succession, and pollution from stormwater discharge. In addition, some populations are extremely localized and have been extirpated by over-collecting to supply the illegal pet trade. Spotted turtles are protected at the state level nearly throughout their range, but continue to decline. Effective conservation and restoration plans require clearly definable units of management. Spotted turtle management units are currently defined as metapopulations consisting of contiguous wetlands along stream corridors. The principal processes in metapopulation dynamics are extirpation of local subpopulations followed by migration from larger subpopulations and recolonization of regions vacant due to extirpation (Hanski and Gilpin 1997). How these processes affect population dynamics and evolution within subpopulations and across the entire metapopulation is a key question for managers. Environmental patchiness forces species to be structured into hierarchical systems of local populations within which conspecifics are more likely to interact than with across other systems of populations. Isolation, however, is usually not complete and since most organisms have some power of dispersal, members of a local population have a low but positive probability of interaction with individuals from other localities (Weins 1997). Demographic and genetic dynamics will be influenced by the rate of migration among systems of populations as well as local birth and death rates. No genetic information exists on population structure, levels of gene flow, or relatedness of any geographic population of spotted turtles. A thorough understanding of the evolutionary relationships (i.e., levels of gene exchange) among geographically proximate and distal populations is required to develop management strategies for maintaining evolutionarily significant spotted turtle lineages to ensure long-term population stability and to reduce the need for further protection through the regulatory process at the federal level. Techniques from molecular biology have achieved an important place in contemporary conservation biology as robust tools to identify reproductive isolation among populations, delineate management units and allow assessment of conservation priorities from an evolutionary perspective. Codominant genetic markers with Mendelian inheritance will allow full assessment of population structure, gene flow, kinship, introgression, hybridization and speciation. The development of tandemly repeated DNA simple sequence motif markers, or microsatellites (Tautz 1989; Queller et al. 1993), provides an ideal tool to investigate the degree of relatedness among species exhibiting small effective population sizes because of the hyper-polymorphism observed. Although the reason for the ubiquitous distribution of microsatellites throughout eukaryotic genomes has not been resolved (Tautz 1989), they have been lauded as the most useful class of nuclear marker available (Queller et al. 1993) due to their hypervariability and ease of sampling. Amplification of microsatellites using the Polymerase Chain Reaction (PCR) allows the survey of a large number of markers in DNA collected from a minimally invasive tissue sample. Sequence homology of regions flanking the microsatellite DNA marker has also permitted use of these markers in closely related species (Schlötter et al. 1991; Gotelli et al. 1994; Scribner et al. 1996; May et al. 1997). Microsatellite DNA markers have been remarkably useful in identification of recently diverged lineages in the bog turtle (Clemmys muhlenbergii, King et al. in preparation), a close relative of the spotted turtle. This proposed research addresses high priority needs at the agency, inter-agency, and programmatic levels by: 1) working with others (e.g., state agencies) to determine the population structure and evolutionary (systematic) relationships among important biological resources (BRD mission); 2) addressing needs of other Department of Interior agencies such as providing information on geographic population structure and critical habitat (USFWS) and development of new techniques for systematic assessment of wildlife species (USFWS, BRD); and 3) providing information to develop strategies for maintaining evolutionary lineages that will ensure long-term population stability and reduce the likelihood of requiring protection through federal regulatory processes (BRD). OBJECTIVES Habitats in wetland areas used by humans occur as sharply defined blocks or fragments, and the patchwork nature of the landscape mosaic is especially evident in such environments. “Metapopulations” have been defined in various ways, but generally, a metapopulation is spatially subdivided into a series of local (patch) populations. The classical view emphasizes a balance between extirpation and recolonization of local populations that enables long-term persistence of the metapopulation (Wiens 1997). In reality, the local populations of a metapopulation occur in habitat patches that are immersed in a complex mosaic of other habitat patches, corridors and boundaries. The most obvious effects of this landscape structure are on individual movement patterns among patches and, consequently, on patch-recolonization probabilities. Clearly, individual movement and gene flow is the most important unifying element in both metapopulation dynamics and landscape ecology (Saunders et al. 1991, Wiens 1992). Thus, the objectives of this research initiative are to work with state resource management agencies to: 1) adapt a suite of microsatellite DNA markers developed for use in the bog turtle for application to studies of the spotted turtle where unique multilocus genotypes will be generated for each individual surveyed in this study; 2) delineate management units (i.e., metapopulation extent) and evolutionarily significant lineages among geographic populations of spotted turtles collected throughout the species range; 3) provide a highly successful predictive model to assign individual spotted turtles of unknown origin to their natal geographic population (i.e., for law enforcement purposes); and 4) promptly report the management implications of each aspect of this research to all the state and federal stakeholders.
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U.S. Department of the Interior \|\| U.S. Geological Survey 11700 Leetown Road, Kearneysville, WV 25430, USA URL: http://www.lsc.usgs.gov Maintainer: lsc_webmaster@usgs.gov Last Modified: October 21, 2002 dwn Privacy Policy and Disclaimers \|\| FOIA \|\| Accessibility