TY - JOUR
T1 - Altered functional connectivity and genetic diversity of a threatened salamander in an agroecosystem
AU - Crawford, John A.
AU - Peterman, William E.
AU - Kuhns, Andrew R.
AU - Eggert, Lori S.
N1 - Funding Information:
We thank R. Jansen (IDNR Heritage Biologist, District 14) & D. Hiatt (NRCS-Martinsville, IL) for their work in compiling contacts and suggesting potential sampling sites, and the numerous landowners who graciously granted us access to their wetlands. S. Bales, N. Marioni, A. Price and J. Tiemann assisted in the field and J. Tunnage provided assistance in the lab. Funding for this project was provided by both the Illinois Endangered Species Protection Board and the Illinois Wildlife Preservation Fund as administered by the Illinois Department of Natural Resources. All research was conducted in accordance with animal care protocols of the University of Illinois animal care and use committee (permit # 08228).
Publisher Copyright:
© 2016, Springer Science+Business Media Dordrecht.
PY - 2016/12/1
Y1 - 2016/12/1
N2 - Context: Amphibian metapopulations have become increasingly fragmented in the Midwestern United States, with wetland-breeding salamanders being especially dependent on intact, high-quality forested landscapes. However, the degree to which amphibian populations are isolated, the factors that influence dispersal and, ultimately, functional connectivity remain areas in need of investigation. Objectives and methods: We combined population demographic and genetic approaches to assess how a landscape fragmented by agriculture influences functional connectivity and metapopulation dynamics of a locally threatened salamander (Ambystoma jeffersonianum). Results: We found that the allelic richness and heterozygosity of this species was significantly related to the level of connectivity with other occupied breeding wetlands and that decreased connectivity resulted in increased genetic differentiation. We also found that effective population size appears to be declining and, while correlative, our focal landscape has experienced significant losses of forested upland habitats and potential wetland breeding habitats over the last 200 years. Conclusions: By combining population and landscape genetic analyses with an assessment of regional wetland occupancy, our study has uniquely synthesized genetic and metapopulation processes, while also incorporating the effects of the landscape matrix on dispersal, connectivity, and population differentiation. The significant relationship between connectivity with heterozygosity, allelic richness, and genetic divergence observed in this study reinforces empirical observations of long distance dispersal and movements in ambystomatid salamanders. However, our results show that protection of core habitat around isolated wetlands may not sufficiently minimize genetic differentiation among populations and preserve critical genetic diversity that may be essential for the long-term persistence of local populations.
AB - Context: Amphibian metapopulations have become increasingly fragmented in the Midwestern United States, with wetland-breeding salamanders being especially dependent on intact, high-quality forested landscapes. However, the degree to which amphibian populations are isolated, the factors that influence dispersal and, ultimately, functional connectivity remain areas in need of investigation. Objectives and methods: We combined population demographic and genetic approaches to assess how a landscape fragmented by agriculture influences functional connectivity and metapopulation dynamics of a locally threatened salamander (Ambystoma jeffersonianum). Results: We found that the allelic richness and heterozygosity of this species was significantly related to the level of connectivity with other occupied breeding wetlands and that decreased connectivity resulted in increased genetic differentiation. We also found that effective population size appears to be declining and, while correlative, our focal landscape has experienced significant losses of forested upland habitats and potential wetland breeding habitats over the last 200 years. Conclusions: By combining population and landscape genetic analyses with an assessment of regional wetland occupancy, our study has uniquely synthesized genetic and metapopulation processes, while also incorporating the effects of the landscape matrix on dispersal, connectivity, and population differentiation. The significant relationship between connectivity with heterozygosity, allelic richness, and genetic divergence observed in this study reinforces empirical observations of long distance dispersal and movements in ambystomatid salamanders. However, our results show that protection of core habitat around isolated wetlands may not sufficiently minimize genetic differentiation among populations and preserve critical genetic diversity that may be essential for the long-term persistence of local populations.
KW - Agriculture
KW - Ambystoma jeffersonianum
KW - Dispersal
KW - Fragmentation
KW - Metapopulation
KW - Wetland
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U2 - 10.1007/s10980-016-0394-6
DO - 10.1007/s10980-016-0394-6
M3 - Article
AN - SCOPUS:84969752558
SN - 0921-2973
VL - 31
SP - 2231
EP - 2244
JO - Landscape Ecology
JF - Landscape Ecology
IS - 10
ER -