Geology topics

Wayne E. Thogmartin

Publications and source records attributed to Wayne E. Thogmartin.

At least 19 recordsLinked to original sources

USGS2026

Status and trend of white-cheeked geese wintering in coastal Nestucca Valley, Oregon

The status and trend of wintering goose populations along the coast of the Pacific Northwest is relatively unstudied. We estimated the status and trends of 6 subspecies of white-cheeked geese wintering in Nestucca Valley, Oregon, USA. Surveys conducted from 2007 to 2019 revealed significant variability in weekly counts among subspecies and years. Dusky ( Branta canadensis occidentalis ) and Cackling ( B . hutchinsii minima ) Geese typically arrived by mid-October and stayed until mid-April, while Aleutian Geese showed lower autumn numbers but doubled in spring. Trends indicated a significant delay in Dusky Geese arrival in recent years, with departure dates remaining constant. Total goose use-days averaged 903,899, with notable declines over the period for Aleutian ( B. h. leucopareia ), Taverner's ( B. h. taverneri )/Lesser ( B. c. parvipes ), and Western ( B. c. moffitti ) Geese. Supporting approximately 6000 geese daily, these results underscore the importance of Nestucca Bay National Wildlife Refuge and adjacent lands for wintering geese. These findings also highlight Nestucca Valley's role as a critical late-winter staging ground, particularly for Aleutian Geese, and emphasize that continued monitoring and adaptive management are essential to sustain these populations.

Oregon↗

USGS2026

Leveraging socioeconomic flows to inform shared, migratory species conservation

Migratory species, and the many cultural and economic values they provide, are declining worldwide. Previous research has quantified ecosystem service flows for single migratory species to provide valuable information on the dynamics of socio-ecological systems to inform cross-jurisdictional management. There are efficiencies in implementation to be gained from considering the dynamics of multiple species (e.g., ecological guilds) simultaneously. As proof of concept, this paper demonstrates how ecosystem service flows can be aggregated spatially for a group of three North American migratory species. We further present a flexible approach to estimating how conservation funding can be allocated equitably between regions of the migratory range. Results show that most benefits from these three migratory species are supported locally by habitat within each region, but net interregional flows exist, including a $33.1M annual subsidy from Mexico to the U.S. and Canada. Results also suggest that directing 18% of net conservation funding raised for these species in the U.S. and Canada toward conservation projects in Mexico would redress inequities in shared management responsibility. Considering the values provided by multiple species simultaneously has the potential to broaden coalitions and expedite negotiation of international agreements by providing a better shared understanding of the benefits to each party.

North America↗

USGS2026

Bird migration and energetics simulations incorporating oil spill effects

Oil spills are well-known for causing acute mortality of birds, but sublethal and delayed impacts are less understood. Focusing on the mallard ( Anas platyrhynchos ), we used simulation modeling to explore how sublethal oiling may affect avian survival and breeding ground body condition. We used empirically informed migration and energetics simulations to model hypothetical spills occurring in northern Arkansas, USA occurring in either January to simulate thermoregulatory stress or March to simulate pre-migration effects. We modeled trace and lightly oiled female mallards (≤5% or 6 to 20% of feather area oiled, respectively), incorporating oiling-induced energetic effects on thermoregulation, flight, and energetic gain. We found that mortality was generally higher for simulated spills occurring in January versus March. In the simulations, mallards lost body mass due to oiling, but surviving individuals could partially recover body mass before arriving at the breeding grounds. Including oiling-induced energetic gain effects in simulations increased mortality as well as increased overall variability of simulation results. This modeling effort identified an important gap in knowledge regarding oiled bird energetics, specifically a need to better quantify oiling-induced energetic gain changes. Although the model is currently limited to a specific species and geographic area, it serves as a proof-of-concept for future research and modeling efforts aimed at understanding more broadly the impacts of oil spills on avian populations.

Prairie Pothole region↗

USGS2026

Nonstationary demographic state-space models using unreplicated counts for species undergoing environmental stressors

A fundamental task in ecological statistics is to estimate abundance and growth rate distributions from wildlife monitoring data to inform conservation management. Modeling time series of wildlife populations presents a number of challenges from both statistical and ecological perspectives, including discreteness; lack of replication; nonstationarity; and observation, demographic, and other phenomenological processes. Nonstationary dynamics are often exhibited by populations undergoing environmental stressors. Models must account for these characteristics to produce reliable estimates of abundance and trends, yet estimation can be challenging with unreplicated data. We propose nonstationary demographic state-space models using unreplicated counts for populations undergoing environmental stressors. A reduced growth rate model matches the complexity of the unreplicated count data, and a fecundity bound on growth rate distributions allows the separation of processes affecting growth rates like environmental stressors from those affecting abundance external to growth rates like migration. NDSSMs allow for the embedding of nonstationary model components, and we explore the use of changepoints, volatility clustering, and migration processes. We apply the proposed nonstationary models in case studies of herons affected by predator/competitor reestablishment and three bat species affected by a fungal pathogen causing white-nose syndrome. Nonstationary models outperform stationary models and generalized linear mixed effects models according to model scoring and visual inspection of predictions, and provide estimates more consistent with published values. Incorporating migration improves model fit universally, even with approximate one-way immigration, most likely because populations are extirpated, recolonized, and increase multiple-fold over the upper bound set by species fecundity. In addition, estimates of the timing and severity of the environmental stressor differed for models with migration. Including nonstationary and demographic components in a fecundity-bounded growth rate model improves inference and benefits interpretability of hyperparameters. In turn, this adjusts uncertainties in predictions of abundance and growth rates over time, providing the ingredients needed for informed conservation analysis and for directing future monitoring of at-risk species.

Journal of Agricultural, Biological and Environmen↗

USGS2026

Hierarchical mixture models and high-resolution monitoring data can inform siting and operational strategies to mitigate bat fatalities at wind turbines

Bats provide critical ecosystem services, but bat fatalities due to wind energy development may imperil some bat populations. Statistical models are used to estimate the total fatalities that occur based on carcasses observed during monitoring surveys. Current models often estimate fatalities aggregated across species, time, and/or turbines, but fall short of reliably informing siting and operational collision mitigation strategies that account for species-specific fatality patterns on a fine spatiotemporal scale. We developed a hierarchical mixture model for estimating species-specific covariate effects and total fatalities per species at each turbine on weekly intervals. We applied the model to a high-resolution dataset of bat carcasses found during turbine searches across nineteen wind facilities in Iowa over two years. Our model explains species-specific variation in bat fatalities at individual wind turbines according to turbine proximity to bat habitat, turbine design specifications, seasonal trends, and weather conditions such as nightly air temperature, air pressure, and wind speed. Turbines located on the edge of wind facilities had higher fatalities, and proximity to roosting and foraging habitat accounted for variation in species-specific fatality estimates. These insights into turbine placement effects can inform siting strategies. We also discovered species-specific relationships with average nightly wind speed and air temperature, among other weather conditions, that could inform operational mitigation strategies such as smart curtailment. Our model can transform observations of carcasses found during turbine searches across multiple facilities, years, and variable search efforts into estimates of total fatalities per species associated with species-specific spatial, temporal, and environmental covariate effects.

Ecological Informatics↗

USGS2025

Twenty years (2000-2020) of butterfly monitoring data across the contiguous United States

We present the most comprehensive, integrated, butterfly monitoring dataset ever assembled for the United States. It contains over 1.2 million count records, from 65,000 surveys, representing over 12.6 million individual butterflies. To compile this dataset, we integrated data and harmonized taxonomy across 19 butterfly monitoring programs in the United States – one national, 13 statewide, and 5 local (e.g. individual county or National Park) in scale. In addition to the data, we also provide the taxonomic dictionary used to crosswalk butterfly taxonomy across programs, and the code used to assemble the integrated dataset. The publication of this dataset will inspire new analyses of butterfly population trends and drivers that help to identify solutions to the biodiversity crisis.

contiguous United States↗

USGS2025

Apparent annual survival of adult Golden-winged Warblers (Vermivora chrysoptera) may not differ by sex or region

Understanding range-wide demographic, spatial, and temporal variation in annual survival is essential for managing species of conservation concern. Multi-population models are useful tools for integrating diverse datasets, reducing biases, and deriving survival estimates across differing spatial scales. We conducted a range-wide, multi-population apparent annual survival analysis for a declining songbird, Vermivora chrysoptera (Golden-winged Warbler), using data from 18 sites across its breeding and nonbreeding grounds. This Nearctic-Neotropical migrant breeds in 2 disjunct regional populations, the Great Lakes and Appalachian Mountains, which are experiencing different rates of decline. We aimed to quantify regional-, site-, and sex-specific apparent annual survival estimates to identify geographic patterns or demographic factors influencing population declines. We used simulations to assess the precision of our estimates. Our models did not reveal a substantial difference in apparent annual survival between the Great Lakes (0.41, 95% credible interval (CrI):0.31–0.50) and the Appalachian regions (0.49, 95% CrI: 0.36–0.60), as CrIs overlapped. Site-specific estimates also showed no clear differences in apparent annual survival among sites representing both regional populations. Male apparent annual survival tended to be greater than female apparent annual survival in both regions, though CrI’s overlapped. Our study suggests demographic factors other than adult annual survival likely play a larger role in recent regional and range-wide population declines, such as productivity, juvenile/immature survival, or recruitment. Simulations indicate that improving recapture probability and study duration of datasets could lead to more precise apparent annual survival estimates. However, our model produced CrI ranges comparable to the most ideal data collection scenario, suggesting the lack of trends we found was not due to variability in our estimates. We stress the importance of addressing inherent biases in survival datasets and the need for standardized collaborative efforts to inform species conservation on a range-wide scale.

Ornithology↗

USGS2025

Density dependence and weather drive dabbling duck spatiotemporal distributions and intercontinental migration

Understanding migratory waterfowl spatiotemporal distributions is important because, in addition to their economic and cultural value, wild waterfowl can be infectious reservoirs of highly pathogenic avian influenza virus (HPAIV). Waterfowl migration has been implicated in regional and intercontinental HPAIV dispersal, and predictive capabilities of where and when HPAIV may be introduced to susceptible spillover hosts would facilitate biosecurity and mitigation efforts. To develop forecasts for HPAIV dispersal, an improved understanding of how individual birds interact with their environment and move on a landscape scale is required. Using an agent-based modeling approach, we integrated individual-scale energetics, species-specific morphology and behavior, and landscape-scale weather and habitat data in a mechanistic stochastic framework to simulate Mallard ( Anas platyrhynchos ) and Northern Pintail ( Anas acuta ) annual migration across the Northern Hemisphere. Our model recreated biologically realistic migratory patterns using a first principles approach to waterfowl ecology, behavior, and physiology. Conducting a limited structural sensitivity analysis comparing reduced models to eBird Status and Trends in reference to the full model, we identified density dependence as the main factor influencing spring migration and breeding distributions, and wind as the main factor influencing fall migration and overwintering distributions. We show evidence of weather patterns in Northeast Asia causing significant intercontinental pintail migration to North America. By linking individual energetics to landscape-scale processes, we identify key drivers of waterfowl migration while developing a predictive model responsive to daily weather patterns. This model paves the way for future waterfowl migration research predicting HPAIV transmission, climate change impacts, and oil spill effects.

Avian Research↗

USGS2025

Three decades of declines restructure butterfly communities in the Midwestern United States

Insects are declining worldwide, yet gaps remain in our understanding of how declines are distributed across species within communities. Using three decades of butterfly monitoring data aggregated from the Midwestern United States, we found that no butterfly species increased in abundance from 1992 to 2023. 59 out of 136 species declined (annual mean trend: −1.2 to −6.9% per year) with losses distributed across all functional groups including residents, migrants, rare, and common species. Community composition changed such that abundance is now more even across species, driven by more severe losses in abundance—but not richness—of common species compared to rare species. These widespread declines are likely cascading across ecosystems. Conservation efforts that focus on entire communities could mitigate butterfly biodiversity loss.

Illinois, Indiana, Iowa, Michigan, Minnesota, Miss↗

USGS2025

U.S. Geological Survey Pollinator Science Strategy, 2025–35—A Review and Look Forward

This “U.S. Geological Survey Pollinator Science Strategy, 2025–35—A Review and Look Forward” (“Pollinator Science Strategy”) describes the science vision of the U.S. Geological Survey (USGS) to support management, conservation, and policy decisions on animal pollinators and their habitats. As the science arm of the Department of the Interior, the USGS has a primary role in providing scientific information to natural resource managers and policymakers across the United States. This “Pollinator Science Strategy” was drafted by a team of USGS pollinator researchers and was further developed through feedback from Federal, State, Tribal, nongovernmental organizations, and industry partners. This “Pollinator Science Strategy” highlights the USGS’s role in the research to promote healthy pollinator populations and address partner information gaps so they can make more informed management decisions. By outlining the importance of USGS science in addressing the information needs of other agencies, organizations, and the public, the “Pollinator Science Strategy” reaffirms the USGS’s commitment to pollinator research and showcases our research priorities for 2025–35. With more than 300 research centers nationally, the USGS is equipped to address pollinator science across scales of complexity and geographic range. USGS pollinator science is organized according to the following five thematic areas: Assessing species ecology, distributions, and natural history requirements. Tracking species status and trends. Understanding species threats and stressors. Informing restoration and management actions. Developing novel methods for improving pollinator research, monitoring, and population outcomes that can benefit our Nation. Our pollinator information products and associated data are made widely available to the public to ensure scientific transparency and accessibility. This “Pollinator Science Strategy” concludes with several research goals that the USGS will work towards from 2025 to 2035, representing our vision for USGS science. These research goals include synthesizing and modernizing the latest information on pollinator threats, developing research that assists managers with habitat design and restoration, providing training to partners on native bee identification and monitoring design, and developing new technologies for assessing the status and trends of our nation’s pollinators.

Circular↗

USGS2025

Quantifying the substantive influence of public comment on United States federal environmental decisions under NEPA

A citizen’s right to comment on, and criticize, government decisions makes a difference. The U.S. National Environmental Policy Act of 1969 (NEPA) institutionalized public engagement in environmental review in the belief it would lead to better decisions and more sustainable outcomes. But, 50 years later, NEPA’s public comment process has been criticized as costly and slow, while doing little to change outcomes. Data science now makes it possible to track progress and evaluate the influence of public participation. We examined 108 environmental impact statement (EIS) processes spanning 22 years. Our analysis revealed that public comments resulted in substantive decision alterations in 62% of cases, with 64% showing modifications to alternatives, 42% showing modifications to mitigation plans and 11% leading to the selection of an entirely new preferred alternative. When federal agencies changed project alternatives (78 EISs), 88% of the time (69 of the 78 EISs) they credited public comments as the reason. In 45 of the 108 EISs, agencies modified mitigation plans and credited public comments as the reason 100% of the time. Agencies only occasionally selected a new preferred alternative (21 out of 104 EISs), but when they did, they credited public comments as the reason 100% of the time. As the United States and the 190+ states and countries that have adopted NEPA’s example consider how to address environmental change, it is important to assess the role of public participation in environmental decision making. Our data say public comments matter.

Environmental Research Letters↗

USGS2025

Additional common milkweed would help Canada meet its share of the trinational eastern migratory monarch butterfly recovery target

The eastern migratory monarch butterfly ( Danaus plexippus ) population has declined by ∼84% between 1993 and 2024. Population recovery in the Midwestern United States is limited by the availability of the monarch's main host plant for egg laying—common milkweed ( Asclepias syriaca ). The extent to which common milkweed availability is limiting in other breeding regions is unknown. Our objective was to determine whether Canada has enough common milkweed to support its share of the trinational eastern migratory monarch population recovery target, given ∼29 stems of common milkweed are needed to contribute one adult monarch into the fall migratory population. To meet this objective, we estimated the number of common milkweed stems in Canada using published common milkweed availability estimates by land cover type. We also estimated the size of the Canadian monarch population if the recovery target was achieved using published estimates of wintering monarch density in Mexico, fall migration survival rates, and the relative proportion of monarchs entering fall migration from Canada. We estimate that Canada currently has 484 million common milkweed stems (range: 111 million–1 billion stems) and increasing this amount by 1.61 times (i.e., by ∼295 million stems), or equivalently, by 61%, would support the recovery target.

Facets↗

USGS2025

A tiered assessment framework for interregional flows of ecosystem services from migratory species

The Intergovernmental Science–Policy Platform on Biodiversity and Ecosystem Services has called for assessments explicitly accounting for interregional flows of ecosystem services (ESs) across geographic scales. An important type of interregional ES flow is generated by the long-distance movements of migratory species. Many migratory species provide important benefits to people, and due to migration dynamics, ESs provided in one location may be affected by habitat conservation, or lack thereof, in other locations. The state of the science on interregional flows of ESs from migratory species, however, is nascent and lacks structure needed to consistently characterize flows. We developed a 4-tiered system for categorizing assessments and the conclusions they can support based on 4 levels of ecological and socioeconomic information, ranging from incomplete to high, and how they are combined. The 4 tiers of assessment are based on differing levels of detail in the estimation of system-level ecological and socioeconomic information on a species and the services it provides: telecoupled ESs, qualitative flows, quantitative static flows, and quantitative dynamic flows. Recent assessment studies largely fall within the first tier, which does not quantify flows. Socioeconomic and ecological information are needed to achieve each tier. Our framework can be used to identify and classify a range of methods, with varying time and data requirements, that can be used to maximize the information content and relevance of ES assessments for migratory species based on available resources.

Conservation Biology↗

USGS2025

A case for assemblage-level conservation to address the biodiversity crisis

Traditional conservation efforts have centred on safeguarding individual species, but these strategies have limitations in a world where entire ecosystems are rapidly changing. Ecosystem conservation can maintain critical ecological functions, but often lacks the detail necessary for the effective conservation of threatened or endangered species. The conservation of such species is mandated by policies and remains a dominant focus of natural resource management. In this Perspective, we propose that assemblage-level conservation targeting groups of taxonomically related or functionally similar species can bridge the gap between species and ecosystems and help to address global biodiversity loss. This approach has previously been limited by data and methodological constraints, but the ongoing growth of biodiversity data, advances in ecological modelling and breakthroughs in computational power have now made effective assemblage-level conservation feasible. Community models provide insights at both the species level and the assemblage level while appropriately accounting for species variability in detection during sampling and uncertainty in biological inferences. Assemblage-level conservation can link both species-specific needs and broader ecological dynamics, ultimately enabling effective strategies for conserving threatened species, ecological communities and ecosystem functions.

Nature Reviews Biodiversity↗

USGS2025

Pesticide contamination detected across five wildlife refuges in the Sacramento Valley of California

An important goal for the applied ecological sciences is to understand the extent to which the biodiversity on conserved or managed lands is exposed to anthropogenic stressors. Among the various categories of conserved lands in the United States, the National Wildlife Refuge System is focused on the protection and management of native wildlife and plant populations. Refuge lands can be associated with wetlands and, especially in California, tend to be near areas of intense human use, including agriculture. The proximity of refuges to cultivated lands results in potential exposure to pesticide drift, which increases the possibility of non-target effects on plants and wildlife. We used a passive sampler approach to quantify aerial pesticide deposition during 28 days in spring of 2023, across five refuges in the Sacramento Valley of California. Pesticides were detected across all refuges and plots within the study area, with 36 individual compounds identified, including insecticides, herbicides, and fungicides, from 176 silicone bands from 49 plots. Distance to agriculture was not an important predictor in our models for most indices of contamination. However, our models revealed that the nearest crop type was an important mediator of the importance of distance to agriculture, as fungicide contamination decreased with distance to agriculture only when orchards were the nearest crop type. The overall lack of distance effects suggests that the interior of refuges in the study area do not necessarily provide more protection from pesticides than refuge edges, although larger refuges could offer more protection. We currently lack information on how the level of contamination found herein is biologically relevant to wildlife, and ongoing monitoring efforts have found productive communities of insects in the study area. The results of this study provide a foundation for future investigations on refuges to analyze impacts of specific pesticide compounds on plants and wildlife.

California↗

USGS2025

Rapid butterfly declines across the United States during the 21st century

Reports of declining insect populations have received widespread media attention, but evidence for declines has been variable across regions and taxonomic groups. Edwards et al . examined trends in the most surveyed taxon: butterflies (see the Perspective by Inouye). Combining data from 35 citizen science programs across the continental US, the authors found declines in overall butterfly abundance over the past 20 years across almost all major regions. Two-thirds of studied species showed declines of more than 10%. Many insects have the potential for rapid population growth and recovery, but habitat restoration, species-specific interventions, and reducing pesticide use are all likely needed to curb population declines.

contiguous United States↗

USGS2024

Potential for spatial coexistence of a transboundary migratory species and wind energy development

Global expansion in wind energy development is a notable achievement of the international community’s effort to reduce carbon emissions during energy production. However, the increasing number of wind turbines have unintended consequences for migratory birds and bats. Wind turbine curtailment and other mitigation strategies can reduce fatalities, but improved spatial and temporal data are needed to identify the most effective way for wind energy development and volant migratory species to coexist. Mexican free-tailed bats ( Tadarida brasiliensis mexicana ) account for a large proportion of known bat fatalities at wind facilities in the southwestern US. We examined the geographic concordance between existing wind energy generation facilities, areas of high wind potential amenable for future deployment of wind facilities, and seasonally suitable habitat for these bats. We used ecological niche modeling to determine species distribution during each of 4 seasons. We used a multi-criteria GIS-based approach to produce a wind turbine siting suitability map. We identified seasonal locations with highest and lowest potential for the species’ probability of occurrence, providing a potential explanation for the higher observed fatalities during fall migration. Thirty percent of 33,606 wind turbines within the southwestern US occurred in highly suitable areas for Mexican free-tailed bats, primarily in west Texas. There is also broad spatial overlap between areas of high wind potential and areas of suitable habitat for Mexican free-tailed bats. Because of this high degree of overlap, our results indicate that post-construction strategies, such as curtailing the timing of operations and deterrents, would be more effective for bat conservation than strategic siting of new wind energy installations.

Scientific Reports↗

USGS2024

Using mobile acoustic monitoring and false-positive N-mixture models to estimate bat abundance and population trends

Estimating the abundance of unmarked animal populations from acoustic data is challenging due to the inability to identify individuals and the need to adjust for observation biases including detectability (false negatives), species misclassification (false positives), and sampling exposure. Acoustic surveys conducted along mobile transects were designed to avoid counting individuals more than once, where raw counts are commonly treated as an index of abundance. More recently, false-positive abundance models have been developed to estimate abundance while accounting for imperfect detection and misclassification. We adapted these methods to model summertime abundance and trends of three species of bats at multiple spatial scales using acoustic recordings collected along mobile transects by partners of the North American Bat Monitoring Program (NABat) from 2012 to 2020. This multiscale modeling spanned individual transect routes, larger NABat grid cells (10 km × 10 km), and across the entire extent of modeled species ranges. We estimated relationships between species abundances and a suite of abiotic and biotic predictors (landcover types, climatological variables, physiographic diversity, building density, and the impacts of white-nose syndrome [WNS]) and found varying levels of support between species. We present clear evidence of substantial declines in populations of tricolored bats ( Perimyotis subflavus ) and little brown bats ( Myotis lucifugus ), declines that corresponded in space and time with the progression of WNS, a devastating disease of hibernating bats. In contrast, our analysis revealed that similar population-wide declines probably have not occurred in big brown bats ( Eptesicus fuscus ), a species known to be less affected by WNS. This study provides the first abundance-based species distribution predictions and population trends for bats in their summer ranges in North America. These models will probably be applicable to assessing wildlife populations in other monitoring programs where acoustic data are used or where false-negative and false-positive detections are present. Finally, our abundance framework (as a spatial point pattern process) can serve as a foundation from which more sophisticated integrated species distribution models that incorporate additional streams of monitoring data (e.g., stationary acoustics, captures) can be developed for North American bats.

Ecological Monographs↗