About

Professor Paul Angermeier is a faculty member in the Fish and Wildlife Conservation department at Virginia Tech. His research broadly focuses on the ecology and conservation of freshwater ecosystems, with particular emphasis on the population dynamics of imperiled fishes, habitat associations of stream fishes, ecosystem services provided by watersheds, use of biotic communities to assess water quality, and impacts of invasive species. His work applies multiple analytical approaches, including field surveys, experiments, and simulations, across various spatial scales such as regional landscapes, watersheds, stream reaches, and habitat patches. The overarching goal of his research is to advance scientific understanding of how ecosystems operate and to make this knowledge accessible to resource managers and stakeholders to promote sustainability.

Research topics

• Ecology
• Biology
• Geotechnical engineering
• Geomorphology
• Cartography
• Environmental science
• Geography
• Geology

Selected publications

• Stream macroinvertebrate responses vary with region, land use and management practice type

  Journal of Environmental Management · 2026-03-06

  articleOpen access

  Intensive land use alters hydrology and water quality, threatening freshwater benthic macroinvertebrates. Over 200,000 management practices (MPs) have been implemented across the Chesapeake Bay watershed since the 1980s, yet biological responses remain inconsistent. We synthesized 29 studies from 4 physiographic provinces covering 8 MP categories and evaluated macroinvertebrate responses along MP gradients using structural (richness), functional (biomass), tolerance, and biotic metrics. We hypothesized that MPs enhancing habitat complexity or restoring flow regimes would benefit taxa sensitive to sediment, hydrologic instability and organic pollution, with outcomes shaped by regional context, land use, and chosen metrics. Four themes emerged. (i) Agricultural Riparian Forest Buffers (RFBs) consistently improved sensitive metrics related to abundance, biomass and richness. (ii) Urban streams with Stream Habitat Improvement and Management (SHIM) showed improved richness and diversity, but biomass and tolerance metrics declined or remained neutral, indicating unresolved hydrologic and pollutant stress. (iii) Structural and functional responses diverged: effect sizes for total and feeding-group biomasses (functional metrics) were negative, whereas genus-level Ephemeroptera-Plecoptera-Trichoptera (EPT) richness (structural metric) was positive, indicating that structural shifts may not track underlying production changes. (iv) Physiographic comparisons showed counterintuitive patterns, as RFBs improved EPT richness in Piedmont streams but had negative effects in the Coastal Plain. Evaluating MP effectiveness requires distinguishing a no-MP pathway (stressors → instream conditions → assemblages → responses) from an MP-mediated pathway (practice regime → modified stressors → instream conditions → assemblages → responses), underscoring the need for region-specific, multi-metric monitoring and improved understanding of MP density thresholds and recovery lags.

  PublisherDOI

• Igniting the transition from water quality to biological condition and ecological health

  Fisheries · 2026-01-01

  article1st authorCorresponding
  PublisherDOI

• Predicting invasiveness of freshwater fishes imported into North America: regional differences in models and outcomes

  Biological Invasions · 2025-03-22 · 1 citations

  articleOpen access

  Abstract Biological invasions driven by international trade heighten the urgency for development of invasion risk models, as the traits and parameters that consistently predict successful invasion remain unresolved. For four regions of North America that include parts of the United States and Canada (Sacramento-San Joaquin River Basins, Lower Colorado River Basin, Great Lakes Region, Mid-Atlantic Region), we construct and compare classification tree models to reveal robust predictors for the establishment and ecological impact stages of freshwater fish invasion. We subsequently apply the models to identify invasive fish species in trade and conduct pathway analyses to determine which trades (aquarium, biological supply, live bait, live food, water garden) and source continents pose the greatest risk to each region. Model results differed by invasion stage and region. Across regions, establishment models shared climate-related predictors including climate match and temperature tolerance. Three of the four impact models contained prior establishment success. The greatest number of species (548) were predicted to establish in the Sacramento-San Joaquin while the fewest (5) were predicted to establish in the Mid-Atlantic. Forty species were predicted to establish in multiple regions, five of which were also predicted to have high impact. The aquarium trade and Asia supplied the most species predicted to establish. Taken together, the results highlight region-specific models, indicating no universal model predicts invasion. Climate-related and prior establishment variables were most useful to risk assessments. The regional models, and identified high-risk pathways and potential invaders, could be applied to prevent future fish invasions in North America.

  PublisherOA PDFDOI

• Management strategy evaluation to assess trade-offs associated with invasive Blue Catfish fisheries and predation impacts

  Marine and Coastal Fisheries · 2025-01-01 · 1 citations

  articleOpen access

  ABSTRACT Objective Many species are intentionally introduced beyond their native range to provide benefits to humans (e.g., food, recreation, or biocontrol). However, introduced species can become invasive and can harm native species, prompting resource managers to explore options to simultaneously conserve native biota and enhance fishing opportunities. Management of Chesapeake Bay Blue Catfish Ictalurus furcatus is complicated because the species supports a renowned trophy fishery and commercial and recreational harvest but also negatively affects native species. Consequently, there is uncertainty and disagreement on how to balance trade-offs associated with varying stakeholder interests. Methods We used a management strategy evaluation to project Blue Catfish population dynamics into the future under different fishery policies to understand whether fishery yield, trophy fishing opportunities, and predation on the economically and ecologically important blue crab Callinectes sapidus could be optimized in the James River, a Chesapeake Bay subestuary. Results Simulated population trajectories indicated that objectives related to maintaining fisheries and conserving prey populations were in conflict. Policies that increased the yield and abundance of trophy-size Blue Catfish (≥100 cm total length) generally increased predation on the blue crab, which supports a valuable fishery. Intense harvest of smaller length-classes and protection of larger Blue Catfish yielded outcomes in which trophy fish abundance increased and blue crab predation declined compared to baseline conditions. However, these outcomes were generally associated with lower Blue Catfish yields after 25 years. There were zero scenarios in which the fishery yield increased and blue crab predation decreased after 25 years. Policies limiting the harvest of small Blue Catfish resulted in large population abundances, suggesting that reducing the abundance of small fish could be important for reducing impacts on native species. Conclusions This study supports the importance of management planning to develop objectives and performance measures based on an improved understanding of trade-offs associated with harvest management for a nonnative fish with economic value.

  PublisherDOI

• Landowners' cognitions and motivations coupled with practice durability influence persistence in grazing agricultural conservation practices in southwest Virginia

  Conservation Science and Practice · 2025-12-29

  articleOpen accessSenior author

  Abstract Agricultural conservation practices are often used to protect stream health while continuing food production. However, recovery of stream health is often not as rapid or extensive as planned. The efficacy of practices may be improved by promoting their continued use by landowners (i.e., persistence) after cost‐share contracts with government agencies end. Persistence rates and their drivers are typically unknown. Therefore, we mail‐surveyed 889 landowners to understand persistence in grazing practices in southwest Virginia. Survey responses were analyzed quantitatively using logistic regression and qualitatively via coding. We found that persistence rates for vegetative practices, cattle‐exclusion fencing, off‐stream watering structures, and pasture management were 74%, 84%, 94%, and 94%, respectively. Both the quantitative and qualitative analyses indicated that landowner cognitions (i.e., attitudes toward practices, environment, and agencies), environmental motivations, and practice durability influence persistence. Our results highlight that persistence could be encouraged by: (1) providing targeted messaging that demonstrates persistence benefits and aligns with landowners' motivations, (2) ensuring that responsibility to maintain practices is transferred during land‐tenure changes, and (3) allocating more agency funding to practice maintenance.

  PublisherOA PDFDOI

• Deposited sediment influences occurrence of functional traits of stream fishes

  Ecology Of Freshwater Fish · 2024-03-07 · 2 citations

  articleOpen access

  Abstract To better understand stream‐fish sensitivity to fine sediment, we documented assemblage‐wide responses by selected traits along a sedimentation gradient. We then discuss the management implications of these ‘dose–response’ relations in the contexts of biotic assessments and conservation of sediment‐sensitive species. We identified a spatial gradient in sediment deposition among streams within the upper Piedmont of the Roanoke River basin in North Carolina and Virginia. We assessed fine‐sediment sensitivity of 81 species based on eight species traits stratified by four attributes: food preference, feeding location, spawning substrate and spawning behaviour. We then ranked each trait and scored each species with respect to its sediment sensitivity. Using data from electrofishing surveys during 2018–2019, we calculated proportional abundances of traits observed at 30 sites throughout the study area and grouped species by their aggregate sensitivity scores. We assessed relations between embeddedness and silt cover and occurrences of species and traits using a combination of regression and ordination approaches. All traits tested responded to embeddedness or silt cover, or both. Feeding traits exhibited the strongest responses to embeddedness, while reproductive traits exhibited the strongest responses to silt cover. Our findings indicate that negative responses of the probability of presence for high‐sensitivity traits to embeddedness and silt cover were linear, with no apparent thresholds. Additionally, proportional abundances of species with multiple high‐sensitivity traits were inversely related to embeddedness and silt cover. Overall, our findings regarding population‐level responses to sedimentation were consistent with our findings for trait‐specific responses. Our analysis of species sensitivity to fine sediment corroborated the patterns we saw in our trait‐specific analyses, indicating that population responses to sedimentation can be predicted from combinations of species traits. The ‘dose–response’ relations we documented may be applicable to managing sediment impacts on fishes, especially in the contexts of biotic assessments and conservation of sediment‐sensitive species.

  PublisherOA PDFDOI

• Connecting conservation practices to local stream health in the Chesapeake Bay watershed

  Fact sheet · 2024-01-01 · 2 citations

  articleOpen access

  First posted July 19, 2024 For additional information, contact: Chesapeake Bay ActivitiesU.S. Geological Survey5522 Research Park DriveBaltimore, MD 21228Contact Pubs Warehouse The Chesapeake Bay Partnership is implementing conservation practices (CPs) throughout the Chesapeake Bay watershed to reduce nutrient and sediment delivery to the Bay. This study intends to provide an integrated and detailed understanding of how local streams respond to these CP-driven management efforts.Key issue: To what extent do CPs positively affect the health of local streams in the nontidal watershed (cobenefits)?Critical unknown: How do CPs change water quality and the stressors that affect stream aquatic life? Which CPs improve stream health more effectively?Critical knowledge to be delivered to stakeholders includes—the effects of CPs on local water-quality conditions,the degree to which these same CPs also provide local stream-ecosystem benefits, anda deeper understanding of local stream-ecosystems, including stressors and CPs, to guide the selection of management efforts that enhance both water quality and overall stream-ecosystem health.

  PublisherOA PDFDOI

• Genetic Structure across Isolated Virginia Populations of the Endangered Candy Darter (Etheostoma osburni)

  Fishes · 2023-10-01

  articleOpen access

  Candy darter Etheostoma osburni, a federally endangered non-game fish, has been extirpated from most of its historic range in Virginia and now occurs in four isolated populations in the New River drainage. Understanding of population genetic structure will provide insights into the recent natural history of the species and can inform conservation management. Our objectives were to: characterize population genetic structure, estimate and compare effective population sizes (Ne), and use this information to infer recent population history. Variation at mitochondrial cytochrome b sequences among 150 individuals showed 10 haplotypes separated by 1–14 mutational steps, some shared and some unique to particular populations. Variation at 12 microsatellite loci among 171 individuals showed lower variation in Dismal Creek than in other populations. All populations showed evidence of having experienced a genetic bottleneck and were highly differentiated from one another based on both types of DNA markers. Population genetic structure was related to stream position in regard to the New River, suggesting that populations were once connected. Ne estimates for all populations were less than the 500 recommended to maintain evolutionary potential, but most estimates were greater than the 100 needed for use as source populations. Our findings indicate that habitat management to allow expansion of populations, and translocations to exchange genetic material among populations, may be effective tactics to promote conservation of candy darter in Virginia.

  PublisherOA PDFDOI

• Global review reveals how disparate study motivations, analytical designs, and focal ions limit understanding of salinization effects on freshwater animals

  The Science of The Total Environment · 2023 · 17 citations

  • Ecology
  • Biology

  . Collectively, concentrations of the ions examined typically spanned five orders of magnitude. Species' invasiveness was a key motivation for studying mollusks, crustaceans, and fishes; threats of urbanization and road salts were key motivations for studying NAI, zooplankton, and amphibians. Laboratory studies were more common than field studies for most taxa. Focal life stages in laboratory studies varied widely but juveniles and adults were represented similarly in field studies. Studies of mollusks, NAI, and crustacean focused on adults; studies of zooplankton, insects, fishes, and amphibians focused on juveniles. Organismal- and population-level responses measuring solute uptake, internal chemistry, body condition, or ion concentrations predominated laboratory studies; population- and assemblage-level responses measuring abundance, spatial distribution, or assemblage composition predominated field studies. Negative responses to salinization predominated but positive and unimodal responses were apparent across all taxa and organizational levels. Key topics for further research include a) salinity responses by more taxa, b) responses to especially toxic ions (i.e., potassium, bicarbonate, sulfate, magnesium), c) mechanisms causing positive and unimodal responses, d) traits underpinning responses, e) effects transcending organizational levels, f) ion-specific response thresholds, and g) interactions between salinity and other stressors. Our review suggests inter-taxa variation in sensitivity to salinization reflects occurrence of certain biological traits, including gill-breathing, semi-permeable skin, multiple life stages, and limited mobility. We propose a traits-based framework to predict salinization sensitivity from shared traits. This evolutionary approach could inform management aimed at preventing or reducing adverse impacts of freshwater salinization.

  PublisherDOI

• Direct and Molecular Observation of Movement and Reproduction by Candy Darter, Etheostoma osburni, an Endangered Benthic Stream Fish in Virginia, USA

  Fishes · 2022-01-27 · 4 citations

  articleOpen accessSenior author

  Direct and indirect measures of individual movement provide valuable knowledge regarding a species’ resiliency to environmental change. Information on patterns of movement can inform species management and conservation but is lacking for many imperiled fishes. The Candy Darter, Etheostoma osburni, is an endangered stream fish with a dramatically reduced distribution in Virginia in the eastern United States, now known from only four isolated populations. We used visual implant elastomer tags and microsatellite DNA markers to directly describe movement patterns in two populations. Parentage analysis based on parent-offspring pairs was used to infer movement patterns of young-of-year and age-1 individuals, as well as the reproductive contribution of certain adults. Direct measurements of movement distances were generally similar between methods, but microsatellite markers revealed greater distances moved, commensurate with greater spatial frames sampled. Parent-offspring pairs were found throughout the species’ 18.8-km distribution in Stony Creek, while most parent-offspring pairs were in 2 km of the 4.25-km distribution in Laurel Creek. Sibship reconstruction allowed us to characterize the mating system and number of spawning years for adults. Our results provide the first measures of movement patterns of Candy Darter as well as the spatial distribution of parent-offspring pairs, which may be useful for selecting collection sites in source populations to be used for translocation or reintroductions. Our results highlight the importance of documenting species movement patterns and spatial distributions of related individuals as steps toward understanding population dynamics and informing translocation strategies. We also demonstrate that the reproductive longevity of this species is greater than previously described, which may be the case for other small stream fishes.

  PublisherOA PDFDOI

Frequent coauthors

• James H. Roberts

  Culham Centre for Fusion Energy

  35 shared

• Eric M. Hallerman

  Virginia Tech

  23 shared

• Emmanuel A. Frimpong

  Virginia Tech

  19 shared

• Amy M. Villamagna

  19 shared

• Richard J. Neves

  Marine Conservation Institute

  17 shared

• Matthew Winston

  14 shared

• Amanda E. Rosenberger

  Tennessee Technological University

  13 shared

• C. Andrew Dolloff

  Virginia Tech

  12 shared

Labs

• Paul Angermeier LabPI