Diet composition: A proximate mechanism explaining stream salamander declines in surface waters with elevated specific conductivity

Jacob M. Hutton; Steven J. Price; Stephen C. Richter; Christopher D. Barton

doi:10.1016/j.gecco.2021.e01719

Diet composition: A proximate mechanism explaining stream salamander declines in surface waters with elevated specific conductivity

Jacob M. Hutton, Steven J. Price, Stephen C. Richter, Christopher D. Barton

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

Changes in land use, such as mountaintop removal mining with valley fills (MTR-VF), often results in headwater streams with elevated specific conductivity (SC). Stream salamanders appear to be particularly sensitive to elevated SC, as previous studies have shown occupancy and abundance decline consistently among all species and life stages as SC increases. Yet, the proximate mechanism responsible for the population declines in streams with elevated SC have eluded researchers. We sampled salamander assemblages across a continuous SC gradient (30–1966 μS/cm) in southeastern Kentucky and examined the diet of larval and adult salamanders to determine if the ratio of aquatic to terrestrial prey (autochthony), total prey volume, aquatic prey importance (I_x), and body condition are influenced by SC. Further, we asked if threshold points for each diet component were present along a gradient of SC. Larval salamanders experienced a 12–fold decline in autochthony at 153 μS/cm, a 4.2–fold decline in total prey volume at 100 μS/cm, a 2.2-fold decline in aquatic I_x at 135 μS/cm, and a rapid decline in body condition as SC increased. Adult salamanders experienced a 3–fold decline in autochthony at 382 μS/cm, no change in prey volumes, a 2-fold decline in aquatic I_x at 163 μS/cm, and a decline in body condition as SC increased. Our results indicate that SC indirectly affects stream salamander populations by changing the composition of diet, which suggests that food availability is a proximate mechanism that leads to reduced population occupancy, abundance, and persistence in streams with elevated SC.

Original language	English
Article number	e01719
Journal	Global Ecology and Conservation
Volume	29
DOIs	https://doi.org/10.1016/j.gecco.2021.e01719
State	Published - Sep 2021

Bibliographical note

Publisher Copyright:
© 2021

Funding

This is contribution number 59 of Lilley Cornett Woods Appalachian Ecological Research Station, Eastern Kentucky University. Funding for this project was provided by the following organizations: Kentucky Academy of Science (Marcia Athey Grant), Tracy Farmer Institute for Sustainability and the Environment, University of Kentucky (Karri Casner Environmental Sciences Fellowship), Appalachian Center, University of Kentucky (Eller Billings Summer Research Mini-Grant), Division of Natural Areas, Eastern Kentucky University (Grant-in-Aid of Student Research Program), the Society for the Study of Amphibians and Reptiles (Roger Conant Grants in Herpetology Program, Conservation of Amphibians and Reptiles), McIntire-Stennis Research Program (Accession Number 1001968), Foundation for the Conservation of Salamanders (Daniel M. Digiacomo Grant), and the Society of Freshwater Science (Graduate Student Conservation Award). The Department of Forestry and Natural Resources at the University of Kentucky further provided resources, facilities, and permission for usage of Robinson Forest and Laurel Fork Surface Mine. We thank Dan Dourson for assistance on micro-gastropod identification and John W. Reynolds for assistance with identifying oligochaetes and Andrea N. Drayer, Wendy Leuenberger, Allison Davis, Rebecca Leloudis, and Millie E. Hamilton for assistance with data collection and analysis. Lastly, we thank the Division of Natural Areas for facility use and access to Lilley Cornett Woods. Research was performed under the University of Kentucky Institutional Animal Care and Use Committee protocol No. 2012-1054 and Kentucky Department of Fish and Wildlife Resources permit No. SC1711117. This is contribution number 59 of Lilley Cornett Woods Appalachian Ecological Research Station, Eastern Kentucky University. Funding for this project was provided by the following organizations: Kentucky Academy of Science (Marcia Athey Grant), Tracy Farmer Institute for Sustainability and the Environment, University of Kentucky (Karri Casner Environmental Sciences Fellowship), Appalachian Center, University of Kentucky (Eller Billings Summer Research Mini-Grant), Division of Natural Areas, Eastern Kentucky University (Grant-in-Aid of Student Research Program), the Society for the Study of Amphibians and Reptiles (Roger Conant Grants in Herpetology Program, Conservation of Amphibians and Reptiles), McIntire-Stennis Research Program (Accession Number 1001968 ), Foundation for the Conservation of Salamanders (Daniel M. Digiacomo Grant), and the Society of Freshwater Science (Graduate Student Conservation Award). The Department of Forestry and Natural Resources at the University of Kentucky further provided resources, facilities, and permission for usage of Robinson Forest and Laurel Fork Surface Mine. We thank Dan Dourson for assistance on micro-gastropod identification and John W. Reynolds for assistance with identifying oligochaetes and Andrea N. Drayer, Wendy Leuenberger, Allison Davis, Rebecca Leloudis, and Millie E. Hamilton for assistance with data collection and analysis. Lastly, we thank the Division of Natural Areas for facility use and access to Lilley Cornett Woods. Research was performed under the University of Kentucky Institutional Animal Care and Use Committee protocol No. 2012-1054 and Kentucky Department of Fish and Wildlife Resources permit No. SC1711117.

Funders	Funder number
Allison Davis
University of Kentucky Center for Appalachian Research in Environmental Sciences
Eastern Kentucky University Division of Natural Areas
Society for the Study of Amphibians and Reptiles, Foundation for the Conservation of Salamanders
Kentucky Department of Fish and Wildlife Resources	SC1711117
McIntire-Stennis Cooperative Forestry Research Program	1001968
Rebecca Leloudis
Society for Freshwater Science
Tracy Farmer Institute for Sustainability and the Environment
University of Kentucky Institutional Animal Care	2012-1054
Society for the Study of Amphibians and Reptiles
University of Kentucky
Eastern Kentucky, University
Kentucky Academy of Science

Keywords

Amphibian diet
Appalachia
Mining
Specific conductivity
Stream salamanders
Thresholds

ASJC Scopus subject areas

Ecology, Evolution, Behavior and Systematics
Ecology
Nature and Landscape Conservation

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1016/j.gecco.2021.e01719

Cite this

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title = "Diet composition: A proximate mechanism explaining stream salamander declines in surface waters with elevated specific conductivity",

abstract = "Changes in land use, such as mountaintop removal mining with valley fills (MTR-VF), often results in headwater streams with elevated specific conductivity (SC). Stream salamanders appear to be particularly sensitive to elevated SC, as previous studies have shown occupancy and abundance decline consistently among all species and life stages as SC increases. Yet, the proximate mechanism responsible for the population declines in streams with elevated SC have eluded researchers. We sampled salamander assemblages across a continuous SC gradient (30–1966 μS/cm) in southeastern Kentucky and examined the diet of larval and adult salamanders to determine if the ratio of aquatic to terrestrial prey (autochthony), total prey volume, aquatic prey importance (Ix), and body condition are influenced by SC. Further, we asked if threshold points for each diet component were present along a gradient of SC. Larval salamanders experienced a 12–fold decline in autochthony at 153 μS/cm, a 4.2–fold decline in total prey volume at 100 μS/cm, a 2.2-fold decline in aquatic Ix at 135 μS/cm, and a rapid decline in body condition as SC increased. Adult salamanders experienced a 3–fold decline in autochthony at 382 μS/cm, no change in prey volumes, a 2-fold decline in aquatic Ix at 163 μS/cm, and a decline in body condition as SC increased. Our results indicate that SC indirectly affects stream salamander populations by changing the composition of diet, which suggests that food availability is a proximate mechanism that leads to reduced population occupancy, abundance, and persistence in streams with elevated SC.",

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doi = "10.1016/j.gecco.2021.e01719",

language = "English",

volume = "29",

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AU - Barton, Christopher D.

PY - 2021/9

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AB - Changes in land use, such as mountaintop removal mining with valley fills (MTR-VF), often results in headwater streams with elevated specific conductivity (SC). Stream salamanders appear to be particularly sensitive to elevated SC, as previous studies have shown occupancy and abundance decline consistently among all species and life stages as SC increases. Yet, the proximate mechanism responsible for the population declines in streams with elevated SC have eluded researchers. We sampled salamander assemblages across a continuous SC gradient (30–1966 μS/cm) in southeastern Kentucky and examined the diet of larval and adult salamanders to determine if the ratio of aquatic to terrestrial prey (autochthony), total prey volume, aquatic prey importance (Ix), and body condition are influenced by SC. Further, we asked if threshold points for each diet component were present along a gradient of SC. Larval salamanders experienced a 12–fold decline in autochthony at 153 μS/cm, a 4.2–fold decline in total prey volume at 100 μS/cm, a 2.2-fold decline in aquatic Ix at 135 μS/cm, and a rapid decline in body condition as SC increased. Adult salamanders experienced a 3–fold decline in autochthony at 382 μS/cm, no change in prey volumes, a 2-fold decline in aquatic Ix at 163 μS/cm, and a decline in body condition as SC increased. Our results indicate that SC indirectly affects stream salamander populations by changing the composition of diet, which suggests that food availability is a proximate mechanism that leads to reduced population occupancy, abundance, and persistence in streams with elevated SC.

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Diet composition: A proximate mechanism explaining stream salamander declines in surface waters with elevated specific conductivity

Abstract

Bibliographical note

Funding

Keywords

ASJC Scopus subject areas

UN SDGs

Access to Document

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Cite this