Mary Freeman, Ph.D.
Mary Freeman is a research ecologist with the Eastern Ecological Science Center at Athens, GA.
She received a B.S. in biology (1979), a M.S. in entomology (1982) and a Ph.D. in forest resources (1990) from the University of Georgia. Before joining Patuxent, Mary conducted research for the U.S. Fish and Wildlife Service and the National Biological Service in Auburn, AL (1992-1996). Mary serves as affiliate faculty at the Odum School of Ecology, University of Georgia, and on the graduate faculties at the University of Georgia and Auburn University.
Science and Products
Observed monitoring data and predictive modelling help understand ongoing and future vulnerability of Chesapeake Bay watershed stream fish communities to climate and land-use change
Issue: The Chesapeake Bay Watershed (CBW) is experiencing effects of climate (warming temperatures and shifting precipitation patterns) and land-use/land-cover (LULC; transition from forest or agriculture to developed lands) change, and these trends are likely to continue under future scenarios of warming and population growth. Stream biodiversity may be vulnerable to ongoing and future climate...
Assessing Faunal Recovery in a Headwater Stream
A catastrophic fish-kill in a small tributary stream of the Etowah River system (Dawson County, Georgia) has created the opportunity to assess faunal recovery, including recolonization by a federally-listed fish species (the Cherokee darter Etheostoma scotti ). Fishes are expected to recolonize Flat Creek by moving upstream from downstream sources. In particular, Flat Creek flows into a larger...
Quantifying Restoration Benefits to Native Stream Fishes
This project is a collaboration of scientists from the USGS and University of Georgia to collect and analyze data describing how small-stream fishes use habitats created through stream restoration activities. The USFWS Region 4 requested this Science Support Partnership (SSP) project as a means to evaluate the effectiveness of stream restoration (primarily in north Georgia, and potentially in...
Synthesizing Multiple Long-Term Datasets to Test Flow Ecology Relationships for Fishes - Workshop
River ecosystems support a wide diversity of biota, including thousands of fish species, which are variously adapted to the dynamic environments provided by flowing-water habitats. One of the primary ways that human activities diminish the biological capacity of rivers is by altering the natural hydrologic variability of river systems through regulation and diversion of streamflow for other uses.
WaterSMART: Apalachicola/Chattahoochee/ Flint River (ACF) Basin
The Challenge: The DOI WaterSMART (Sustain and Manage America’s Resources for Tomorrow) initiative is developing data and tools to help water managers identify current and future water shortages, for humans and for freshwater ecosystems. Fishes, for example, can decline in diversity and abundance when streamflow becomes too low, for too long. However, ecologists find that effects of declining...
Quantifying Effects of Flow Variability on Riverine Biota
Stream and river biota around the world are imperiled by alterations to stream flow regimes that result from dams, land-use changes, water diversions and changing climate patterns. To manage and conserve stream-dependent species threatened by flow alterations, natural resource managers need quantitative information relating multiple aspects of ecological response to changes in a stream’s flow...
Southeast Regional Assessment Project (SERAP): Assessing Global Change Impacts on Natural and Human Systems in the Southeast
The Southeastern United States spans a broad range of physiographic settings and maintains exceptionally high levels of faunal diversity. Unfortunately, many of these ecosystems are increasingly under threat due to rapid human development, and management agencies are increasingly aware of the potential effects that climate change will have on these ecosystems. Natural resource managers and conserv
USGS-USFS Partnership to Help Managers Evaluate Conservation Strategies for Aquatic Ecosystems Based on Future Climate Projections
The Southeastern U.S. spans broad ranges of physiographic settings and contains a wide variety of aquatic systems that provide habitat for hundreds of endemic aquatic species that pose interesting challenges and opportunities for managers of aquatic resources, particularly in the face of climate change. For example, the Southeast contains the southernmost populations of the eastern brook trout and
Native riverine fish occurrences downstream from two hydropower dams with contrasting operations, Georgia, USA
Data are fish species occurrences in surveys made by backpack electrofishing and seining in shoal habitats in the Etowah River downstream from Allatoona Dam (n=10 surveys in 2010 and n=5 surveys in 2016; 20 taxa total) and in the Coosawattee River downstream from Carters Dam and re-regulation dam (n=11 surveys in 2010; 32 taxa total), Georgia, USA. Data for the Etowah River include counts of indiv
Slow recovery of headwater-stream fishes following a catastrophic poisoning event
Fish collection data for surveys made at 5 localities in Flat Creek, Dawson County GA, on 6 dates that spanned a 4 to 18.5-month period following a catastrophic fish kill caused by a chemical spill near the headwater origin on Flat Creek. The data are: locality descriptions, water depth and velocity measurements made during fish sampling, and tabulated numbers and range in body length of individua
Annual survival, site fidelity, and longevity in the eastern population of the Painted Bunting (Passerina ciris)
Data comprise 6632 observations of individually banded Painted Buntings, captured and observed from 1999-2016 at 40 study locations on the southeastern Atlantic Coast (NC, SC, GA and FL, US).
Filter Total Items: 108
How low is too low? Partnering with stakeholders and managers to define ecologically based low-flow thresholds in a perennial temperate river
Managing aquatic ecosystems for people and nature can be improved by collaboration among scientists, managers, decision-makers, and other stakeholders. Many collaborative and interdisciplinary approaches have been developed to address the management of freshwater ecosystems; however, there are still barriers to overcome. We worked as part of a regional stakeholder group comprising municipal water
Authors
Laura Rack, Mary Freeman, Ben N. Emanuel, Laura S. Craig, Stephen W. Golladay, Carol Yang, Seth J. Wenger
Life-history connections to long-term fish population trends in a species-rich temperate river
Fishes exhibit a diverse range of traits encompassing life-history strategies, feeding behaviours and spawning behaviours. These traits mediate fish population responses to changing environmental conditions such as those caused by anthropogenic stressors. The Conasauga River, located in northwestern Georgia and southeastern Tennessee, USA, hosts a diverse assemblage of over 75 species of freshwate
Authors
Andrew J. Nagy, Mary Freeman, Brian J. Irwin, Seth J. Wenger
Decomposition rates appear stable despite elevated shrimp abundances following hurricanes in montane streams, Puerto Rico
Leaf litter decomposition is a key ecosystem process in headwater streams, influenced by physical fragmentation, microbial degradation and feeding activity by stream biota. In some tropical streams, feeding by freshwater shrimps can exert strong top-down control on leaf litter decomposition, however, variation in shrimp macroconsumer effects across small spatial scales or among years is not well-k
Authors
Max Kelly, Mary Freeman, Pablo E. Gutiérrez-Fonseca, Jesus E. Gomez, Rafael Perez, Lulu Lacey, Alonso Ramírez, Catherine M. Pringle
Biodiversity connections—‘ties that bind’
Connectivity is a foundational concept in ecology and conservation and was the organising theme for the 2022 Annual Meeting of the Southeastern Fishes Council, a professional organisation dedicated to the study and conservation of freshwater fishes native to the southeast region of the United States (US). We introduce a Special Contribution of six papers selected from presentations at that meeting
Authors
Mary Freeman, Duncan Elkins, Brett Albanese
Persistence of native riverine fishes downstream from two hydropower dams with contrasting operations
Identifying hydropower dam operations that lessen detrimental effects on downstream fauna could inform conservation strategies for native fishes. We compared occurrence of native fishes in 20 shoal habitats downstream from two differently operated hydropower dams in the Coosa River system, Georgia, USA. Species richness averaged 7 and 11, respectively, in surveys downstream from (1) a hydropeaking
Authors
Mary Freeman, Brett Albanese, Phillip M. Bumpers, Megan M. Hagler, Andrew J. Nagy, Byron J. Freeman, Seth J. Wenger
Cryptic tolerant fish species and their potential effect on index of biotic integrity (IBI) scores
Indices such as the Index of Biotic Integrity (IBI) are often used by management agencies to estimate the abstract property of stream health. These indices are usually predicated on the belief that certain fish species are tolerant to environmental perturbation while others are sensitive. Species are usually designated as either tolerant or sensitive in these analyses based on inherent ecological
Authors
Bryson G. Hilburn, Mary Freeman, Katelyn M. Lawson, Steven J. Rider, Carol E. Johnston
Observed and projected functional reorganization of riverine fish assemblages from global change
Climate and land-use/land-cover change (‘global change’) are restructuring biodiversity, globally. Broadly, environmental conditions are expected to become warmer, potentially drier (particularly in arid regions), and more anthropogenically developed in the future, with spatiotemporally complex effects on ecological communities. We used functional traits to inform Chesapeake Bay Watershed fish res
Authors
Taylor E Woods, Mary Freeman, Kevin P. Krause, Kelly O. Maloney
Stream restoration produces transitory, not permanent, changes to fish assemblages at compensatory mitigation sites
There is inconsistent evidence that stream restoration projects lead to recovery of ecosystem attributes, especially stream biota. While some assessments have documented desired changes in fish community metrics in the first years following restoration, longer-term studies have not always corroborated these findings. In this study, we used data and monitoring reports submitted to federal regulator
Authors
Edward S. Stowe, Kelly N. Petersen, Shishir Rao, Eric J. Walther, Mary Freeman, Seth J. Wenger
Habitat associations of riverine fishes among rocky shoals
Understanding species' associations with physical habitat conditions is a fundamental goal of ecology. For organisms that occupy lotic ecosystems, relationships to streamflow are of particular importance, but these associations are unstudied for most species. We tested the predictability of fish–microhabitat relationships in river shoals (shallow, rocky areas with relatively swift water flow) usin
Authors
Anna Y. Baynes, Mary Freeman, S. Kyle McKay, Seth J. Wenger
Seasonal variability in macroinvertebrate assemblages in paired perennial and intermittent streams in Costa Rica
Ecological effects of flooding and drying events are relatively understudied in the Neotropics and less is known about these hydrological extremes in intermittent streams. Neotropical headwater streams in Costa Rica provide opportunities to evaluate the response of macroinvertebrate communities to seasonal changes in flow regime in relatively human undisturbed systems. We quantified the effects of
Authors
Darixa D Hernandez-Abrams, Scott Connelly, Mary Freeman, Pablo E. Gutierrez-Fonseca, Seth J. Wenger
Simple statistical models can be sufficient for testing hypotheses with population time series data
Time-series data offer wide-ranging opportunities to test hypotheses about the physical and biological factors that influence species abundances. Although sophisticated models have been developed and applied to analyze abundance time series, they require information about species detectability that is often unavailable. We propose that in many cases, simpler models are adequate for testing hypothe
Authors
Seth J. Wenger, Edward S. Stowe, Keith B. Gido, Mary Freeman, Yoichiro Kanno, Nathan R. Franssen, Julian Olden, N. LeRoy Poff, Annika W. Walters, Phillip M. Bumpers, Meryl C. Mims, Mevin B. Hooten, Xinyi Lu
Multispecies approaches to status assessments in support of endangered species classifications
Multispecies risk assessments have developed within many international conservation programs, reflecting a widespread need for efficiency. Under the United States Endangered Species Act (ESA), multispecies assessments ultimately lead to species-level listing decisions. Although this approach provides opportunities for improved efficiency, it also risks overwhelming or biasing the assessment proces
Authors
Daniel Bruce Fitzgerald, Mary Freeman, Kelly O. Maloney, John A. Young, Amanda E. Rosenberger, David C. Kazyak, David R. Smith
Science and Products
Observed monitoring data and predictive modelling help understand ongoing and future vulnerability of Chesapeake Bay watershed stream fish communities to climate and land-use change
Issue: The Chesapeake Bay Watershed (CBW) is experiencing effects of climate (warming temperatures and shifting precipitation patterns) and land-use/land-cover (LULC; transition from forest or agriculture to developed lands) change, and these trends are likely to continue under future scenarios of warming and population growth. Stream biodiversity may be vulnerable to ongoing and future climate...
Assessing Faunal Recovery in a Headwater Stream
A catastrophic fish-kill in a small tributary stream of the Etowah River system (Dawson County, Georgia) has created the opportunity to assess faunal recovery, including recolonization by a federally-listed fish species (the Cherokee darter Etheostoma scotti ). Fishes are expected to recolonize Flat Creek by moving upstream from downstream sources. In particular, Flat Creek flows into a larger...
Quantifying Restoration Benefits to Native Stream Fishes
This project is a collaboration of scientists from the USGS and University of Georgia to collect and analyze data describing how small-stream fishes use habitats created through stream restoration activities. The USFWS Region 4 requested this Science Support Partnership (SSP) project as a means to evaluate the effectiveness of stream restoration (primarily in north Georgia, and potentially in...
Synthesizing Multiple Long-Term Datasets to Test Flow Ecology Relationships for Fishes - Workshop
River ecosystems support a wide diversity of biota, including thousands of fish species, which are variously adapted to the dynamic environments provided by flowing-water habitats. One of the primary ways that human activities diminish the biological capacity of rivers is by altering the natural hydrologic variability of river systems through regulation and diversion of streamflow for other uses.
WaterSMART: Apalachicola/Chattahoochee/ Flint River (ACF) Basin
The Challenge: The DOI WaterSMART (Sustain and Manage America’s Resources for Tomorrow) initiative is developing data and tools to help water managers identify current and future water shortages, for humans and for freshwater ecosystems. Fishes, for example, can decline in diversity and abundance when streamflow becomes too low, for too long. However, ecologists find that effects of declining...
Quantifying Effects of Flow Variability on Riverine Biota
Stream and river biota around the world are imperiled by alterations to stream flow regimes that result from dams, land-use changes, water diversions and changing climate patterns. To manage and conserve stream-dependent species threatened by flow alterations, natural resource managers need quantitative information relating multiple aspects of ecological response to changes in a stream’s flow...
Southeast Regional Assessment Project (SERAP): Assessing Global Change Impacts on Natural and Human Systems in the Southeast
The Southeastern United States spans a broad range of physiographic settings and maintains exceptionally high levels of faunal diversity. Unfortunately, many of these ecosystems are increasingly under threat due to rapid human development, and management agencies are increasingly aware of the potential effects that climate change will have on these ecosystems. Natural resource managers and conserv
USGS-USFS Partnership to Help Managers Evaluate Conservation Strategies for Aquatic Ecosystems Based on Future Climate Projections
The Southeastern U.S. spans broad ranges of physiographic settings and contains a wide variety of aquatic systems that provide habitat for hundreds of endemic aquatic species that pose interesting challenges and opportunities for managers of aquatic resources, particularly in the face of climate change. For example, the Southeast contains the southernmost populations of the eastern brook trout and
Native riverine fish occurrences downstream from two hydropower dams with contrasting operations, Georgia, USA
Data are fish species occurrences in surveys made by backpack electrofishing and seining in shoal habitats in the Etowah River downstream from Allatoona Dam (n=10 surveys in 2010 and n=5 surveys in 2016; 20 taxa total) and in the Coosawattee River downstream from Carters Dam and re-regulation dam (n=11 surveys in 2010; 32 taxa total), Georgia, USA. Data for the Etowah River include counts of indiv
Slow recovery of headwater-stream fishes following a catastrophic poisoning event
Fish collection data for surveys made at 5 localities in Flat Creek, Dawson County GA, on 6 dates that spanned a 4 to 18.5-month period following a catastrophic fish kill caused by a chemical spill near the headwater origin on Flat Creek. The data are: locality descriptions, water depth and velocity measurements made during fish sampling, and tabulated numbers and range in body length of individua
Annual survival, site fidelity, and longevity in the eastern population of the Painted Bunting (Passerina ciris)
Data comprise 6632 observations of individually banded Painted Buntings, captured and observed from 1999-2016 at 40 study locations on the southeastern Atlantic Coast (NC, SC, GA and FL, US).
Filter Total Items: 108
How low is too low? Partnering with stakeholders and managers to define ecologically based low-flow thresholds in a perennial temperate river
Managing aquatic ecosystems for people and nature can be improved by collaboration among scientists, managers, decision-makers, and other stakeholders. Many collaborative and interdisciplinary approaches have been developed to address the management of freshwater ecosystems; however, there are still barriers to overcome. We worked as part of a regional stakeholder group comprising municipal water
Authors
Laura Rack, Mary Freeman, Ben N. Emanuel, Laura S. Craig, Stephen W. Golladay, Carol Yang, Seth J. Wenger
Life-history connections to long-term fish population trends in a species-rich temperate river
Fishes exhibit a diverse range of traits encompassing life-history strategies, feeding behaviours and spawning behaviours. These traits mediate fish population responses to changing environmental conditions such as those caused by anthropogenic stressors. The Conasauga River, located in northwestern Georgia and southeastern Tennessee, USA, hosts a diverse assemblage of over 75 species of freshwate
Authors
Andrew J. Nagy, Mary Freeman, Brian J. Irwin, Seth J. Wenger
Decomposition rates appear stable despite elevated shrimp abundances following hurricanes in montane streams, Puerto Rico
Leaf litter decomposition is a key ecosystem process in headwater streams, influenced by physical fragmentation, microbial degradation and feeding activity by stream biota. In some tropical streams, feeding by freshwater shrimps can exert strong top-down control on leaf litter decomposition, however, variation in shrimp macroconsumer effects across small spatial scales or among years is not well-k
Authors
Max Kelly, Mary Freeman, Pablo E. Gutiérrez-Fonseca, Jesus E. Gomez, Rafael Perez, Lulu Lacey, Alonso Ramírez, Catherine M. Pringle
Biodiversity connections—‘ties that bind’
Connectivity is a foundational concept in ecology and conservation and was the organising theme for the 2022 Annual Meeting of the Southeastern Fishes Council, a professional organisation dedicated to the study and conservation of freshwater fishes native to the southeast region of the United States (US). We introduce a Special Contribution of six papers selected from presentations at that meeting
Authors
Mary Freeman, Duncan Elkins, Brett Albanese
Persistence of native riverine fishes downstream from two hydropower dams with contrasting operations
Identifying hydropower dam operations that lessen detrimental effects on downstream fauna could inform conservation strategies for native fishes. We compared occurrence of native fishes in 20 shoal habitats downstream from two differently operated hydropower dams in the Coosa River system, Georgia, USA. Species richness averaged 7 and 11, respectively, in surveys downstream from (1) a hydropeaking
Authors
Mary Freeman, Brett Albanese, Phillip M. Bumpers, Megan M. Hagler, Andrew J. Nagy, Byron J. Freeman, Seth J. Wenger
Cryptic tolerant fish species and their potential effect on index of biotic integrity (IBI) scores
Indices such as the Index of Biotic Integrity (IBI) are often used by management agencies to estimate the abstract property of stream health. These indices are usually predicated on the belief that certain fish species are tolerant to environmental perturbation while others are sensitive. Species are usually designated as either tolerant or sensitive in these analyses based on inherent ecological
Authors
Bryson G. Hilburn, Mary Freeman, Katelyn M. Lawson, Steven J. Rider, Carol E. Johnston
Observed and projected functional reorganization of riverine fish assemblages from global change
Climate and land-use/land-cover change (‘global change’) are restructuring biodiversity, globally. Broadly, environmental conditions are expected to become warmer, potentially drier (particularly in arid regions), and more anthropogenically developed in the future, with spatiotemporally complex effects on ecological communities. We used functional traits to inform Chesapeake Bay Watershed fish res
Authors
Taylor E Woods, Mary Freeman, Kevin P. Krause, Kelly O. Maloney
Stream restoration produces transitory, not permanent, changes to fish assemblages at compensatory mitigation sites
There is inconsistent evidence that stream restoration projects lead to recovery of ecosystem attributes, especially stream biota. While some assessments have documented desired changes in fish community metrics in the first years following restoration, longer-term studies have not always corroborated these findings. In this study, we used data and monitoring reports submitted to federal regulator
Authors
Edward S. Stowe, Kelly N. Petersen, Shishir Rao, Eric J. Walther, Mary Freeman, Seth J. Wenger
Habitat associations of riverine fishes among rocky shoals
Understanding species' associations with physical habitat conditions is a fundamental goal of ecology. For organisms that occupy lotic ecosystems, relationships to streamflow are of particular importance, but these associations are unstudied for most species. We tested the predictability of fish–microhabitat relationships in river shoals (shallow, rocky areas with relatively swift water flow) usin
Authors
Anna Y. Baynes, Mary Freeman, S. Kyle McKay, Seth J. Wenger
Seasonal variability in macroinvertebrate assemblages in paired perennial and intermittent streams in Costa Rica
Ecological effects of flooding and drying events are relatively understudied in the Neotropics and less is known about these hydrological extremes in intermittent streams. Neotropical headwater streams in Costa Rica provide opportunities to evaluate the response of macroinvertebrate communities to seasonal changes in flow regime in relatively human undisturbed systems. We quantified the effects of
Authors
Darixa D Hernandez-Abrams, Scott Connelly, Mary Freeman, Pablo E. Gutierrez-Fonseca, Seth J. Wenger
Simple statistical models can be sufficient for testing hypotheses with population time series data
Time-series data offer wide-ranging opportunities to test hypotheses about the physical and biological factors that influence species abundances. Although sophisticated models have been developed and applied to analyze abundance time series, they require information about species detectability that is often unavailable. We propose that in many cases, simpler models are adequate for testing hypothe
Authors
Seth J. Wenger, Edward S. Stowe, Keith B. Gido, Mary Freeman, Yoichiro Kanno, Nathan R. Franssen, Julian Olden, N. LeRoy Poff, Annika W. Walters, Phillip M. Bumpers, Meryl C. Mims, Mevin B. Hooten, Xinyi Lu
Multispecies approaches to status assessments in support of endangered species classifications
Multispecies risk assessments have developed within many international conservation programs, reflecting a widespread need for efficiency. Under the United States Endangered Species Act (ESA), multispecies assessments ultimately lead to species-level listing decisions. Although this approach provides opportunities for improved efficiency, it also risks overwhelming or biasing the assessment proces
Authors
Daniel Bruce Fitzgerald, Mary Freeman, Kelly O. Maloney, John A. Young, Amanda E. Rosenberger, David C. Kazyak, David R. Smith