Mary Freeman, Ph.D.
Biography
Mary Freeman is a research ecologist with the Patuxent Wildlife Research Center and is stationed in 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
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...
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...
Fish
The health of freshwater fish populations is tied closely to competing demands and uses for this resource. Patuxent scientists are applying mark-recapture science and other methods developed for the adapative management of waterfowl to help manage freshwater fish and their habitats.
Freshwater
Our nation’s rivers have many uses. People have altered the flow of some rivers through diversions, dams, and water use. Such changes can affect fish populations and our scientist work to understand these effects by answering such questions as “How is survival of young fish affected by streamflow patterns?” and “How do fish communities respond to changes in water management?”
Occupancy
Many wildlife studies seek to understand changes or differences in the proportion of sites occupied by a species of interest. These studies are hampered by imperfect detection of these species, which can result in some sites appearing to be unoccupied that are actually occupied. Occupancy models solve this problem and produce unbiased estimates of occupancy (ie, occurrence) and related...
Capture-Mark-Recapture Science
Capture-Mark-Recapture (CMR) can be viewed as an animal survey method in which the count statistic is the total number of animals caught, and the associated detection probability is the probability of capture. The method involves capturing a number of animals, marking them, releasing them back into the population, and then determining the ratio of marked to unmarked animals in the population...
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...
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...
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...
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...
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).
A Bayesian framework for assessing extinction risk based on ordinal categories of population condition and projected landscape change
Many at-risk species lack standardized surveys across their range or quantitative data capable of detecting demographic trends. As a result, extinction risk assessments often rely on ordinal categories of risk based on explicit criteria or expert elicitation. This study demonstrates a Bayesian approach to assessing extinction risk based on this...
Fitzgerald, Daniel Bruce; Henderson, Andrew R; Maloney, Kelly O.; Freeman, Mary; Young, John A.; Rosenberger, Amanda E.; Kazyak, David; Smith, David R.
Ecological forecasting—21st century science for 21st century management
Natural resource managers are coping with rapid changes in both environmental conditions and ecosystems. Enabled by recent advances in data collection and assimilation, short-term ecological forecasting may be a powerful tool to help resource managers anticipate impending near-term changes in ecosystem conditions or dynamics. Managers may use the...
Bradford, John B.; Weltzin, Jake F.; Mccormick, Molly; Baron, Jill; Bowen, Zack; Bristol, Sky; Carlisle, Daren; Crimmins, Theresa; Cross, Paul; DeVivo, Joe; Dietze, Mike; Freeman, Mary; Goldberg, Jason; Hooten, Mevin; Hsu, Leslie; Jenni, Karen; Keisman, Jennifer; Kennen, Jonathan; Lee, Kathy; Lesmes, David; Loftin, Keith; Miller, Brian W.; Murdoch, Peter; Newman, Jana; Prentice, Karen L.; Rangwala, Imtiaz; Read, Jordan; Sieracki, Jennifer; Sofaer, Helen; Thur, Steve; Toevs, Gordon; Werner, Francisco; White, C. LeAnn; White, Timothy; Wiltermuth, Mark Incorporating spatial synchrony in the status assessment of a threatened species with multivariate analysis
Spatial synchrony—correlated abundance fluctuations among distinct populations—is associated with increased extinction risk but is not a component of widely-used extinction risk assessments (e.g., IUCN Red List, U.S. Fish and Wildlife Service’s Species Status Assessment). Alongside traditional viability metrics (i.e., the number of populations,...
Stowe, Edward; Wenger, Seth J.; Freeman, Mary; Freeman, Byron J. Rethinking foundation species in a changing world: The case for Rhododendron maximum as an emerging foundation species in shifting ecosystems of the southern Appalachians
“Foundation species” are widespread, abundant species that play critical roles in structuring ecosystem characteristics and processes. Ecosystem change in response to human activities, climate change, disease introduction, or other environmental conditions may promote the emergence of new foundation species or the decline of previously important...
Dudley, Maura P.; Freeman, Mary; Wenger, Seth J.; Jackson, Rhett; Pringle, Catherine M. Freshwater crabs (Decapoda: Pseudothelphusidae) increase rates of leaf breakdown in a neotropical headwater stream
Freshwater crabs are the largest macroconsumers in many neotropical headwater streams, but few studies have examined their roles in ecosystem processes such as leaf litter breakdown. As omnivorous macroconsumers, freshwater crabs affect multiple trophic levels. They may directly increase leaf breakdown through fragmentation and consumption or...
Yang, Carol; Wenger, Seth J.; Rugenski, Amanda; Wehrtmann, Ingo S.; Connelly, Scott; Freeman, Mary Identifying life history traits that promote occurrence for four minnow (Leuciscidae) species in intermittent Gulf Coastal Plain streams
- Life history traits of stream fishes partly reflect adaptations to disturbance regimes, which in turn shape assemblage composition via environmental filters. In this study, we focused on life history traits of four morphologically similar leuciscid species in coastal plain streams of southwestern GA that are shifting from historically perennial...
Davis, Jessica L.; Freeman, Mary; Golladay, Stephen W. Water velocity regulates macro-consumer herbivory on the benthic macrophyte Podostemum ceratophyllum Michx.
1) Macrophytes influence aquatic ecosystems by increasing habitat complexity and providing trophic resources for aquatic fauna. While herbivory on freshwater macrophytes is widely documented in lakes, low-velocity riverine habitats, the influence of herbivory on macrophytes in higher-velocity habitats has rarely been examined. 2) We...
Wood, James L; Skaggs, Jon W; Conn, Caitlin C; Freeman, Mary Long-term (37 years) impacts of low-head dams on freshwater shrimp habitat connectivity in northeastern Puerto Rico
Freshwater migratory shrimp in Puerto Rico depend on watershed connectivity, from stream headwaters to the ocean, to complete their life cycle. Moreover, shrimp populations in different watersheds are known to be connected in an island-wide metapopulation. However, low-head dams paired with water intakes on streams draining the El Yunque National...
Chappell, Jessica; S. Kyle McKay; Freeman, Mary; Catherine M. Pringle
Adaptive management of flows from R.L. Harris Dam (Tallapoosa River, Alabama)—Stakeholder process and use of biological monitoring data for decision making
Adaptive management has been applied to problems with multiple conflicting objectives in various natural resources settings to learn how management actions affect divergent values regarding system response. Hydropower applications have only recently begun to emerge in the field, yet in the specific example reported herein, stakeholders invested in...
Irwin, Elise R.; Irwin, Elise R.; Freeman, Mary; Peterson, James; Kennedy, Kathryn D.M.; Lloyd, M. Clint; Ouellette Coffman, Kristie M.; Kosnicki, Ely; Hess, Tom Annual survival, site fidelity, and longevity in the eastern coastal population of the Painted Bunting (Passerina ciris) based on a 20-year mark-recapture/resighting study
A long-term study of annual survival, longevity, and site fidelity in the eastern coastal population of the Painted Bunting (Passerina ciris) during the breeding season was conducted from 1999 through 2018 in the outer coastal plain of the southeastern Atlantic coast of the United States. Painted Buntings were uniquely color-banded from 1999...
Sykes, Paul W. Jr; Freeman, Mary; Sykes, Joan J.; Seginak, John T.; M. David Oleyar; Egan, Joshua P. The missing dead: The lost role of animal remains in nutrient cycling in North American Rivers
While leaf litter, wood, and other plant remnants are known to play a central role in lotic ecosystems, animal remains (carcasses, bones, shells) have received less attention. We propose a simple classification scheme for animal remains in rivers based on origin (authochthonous vs. allochthonous) and frequency (pulsed vs continuous). We then...
Wenger, Seth J.; Subalusky, Amanda L.; Freeman, Mary Stream fish colonization but not persistence varies regionally across a large North American river basin
Many species have distributions that span distinctly different physiographic regions, and effective conservation of such taxa will require a full accounting of all factors that potentially influence populations. Ecologists recognize effects of physiographic differences in topography, geology and climate on local habitat configurations, and thus...
Wheeler, Kit; Wenger, Seth J.; Walsh, Stephen J.; Martin, Zachary P.; Jelks, Howard L.; Freeman, Mary