Geology topics

Research about Canada, United States

Source-linked reports with geographic coverage including Canada, United States.

At least 145 records · Page 8Linked to original sources

USGS2025

Assessing shifting technology in genetic monitoring of the North American plains bison Federal conservation herds

Human expansion is a major driver of both declining wildlife abundance and the contraction of species’ distributions, increasing the risk of genetic erosion and the need for genetic monitoring. Rapidly advancing technology has expanded the types of genetic data that are available for wildlife conservation. However, inferences from different genetic markers could result in different management decisions and, thus, must be considered carefully. Rebounding from near extinction in the early 1900s, the majority of North American plains bison ( Bison bison bison ) are managed as small and isolated herds. Microsatellite-based analyses have been used to inform management of the US Federal bison conservation herds since the early 2000s. Transitioning from monitoring with tens of multiallelic loci (e.g., microsatellite loci) to thousands of biallelic loci (e.g., single nucleotide polymorphisms [SNPs]) could increase genotyping efficiency and improve the precision of population genetic inference but would require an understanding of the inferential differences between genetic marker types. We compared microsatellite-based measures of genetic diversity, differentiation, and population structure for 20 bison conservation herds (17 Federal, 1 Tribal, 2 Canadian) to inference from SNP-based analyses for the Tribal herd and 15 of the Federal herds. Data from both genetic marker types found that all herds have remarkably high genetic diversity given the severity of the bottleneck from which these populations recovered, and that population structure was consistent with founding histories. Importantly, SNPs had greater power to describe differences in genetic diversity and groups of related herds, but only if analyses are based on 250 or more loci. Overall, we found that microsatellite and SNP data can provide comparable conservation insight, but SNPs must be carefully selected to ensure continuity in genetic monitoring and to achieve the increased precision in genetic diversity and differentiation among herds that we observed in this study.

Conservation Genetics↗

USGS2025

Upriver migrating sea lamprey exhibit similar responses to hydrodynamic features as other up and downriver-moving species

Identifying commonalities in how fish navigate rivers near infrastructure will enhance water operations and design by improving our ability to predict engineering outcomes (e.g., barrier construction/removal, fish passage installation) in novel settings before the cost of real-world implementation. Evidence from intermediate-scale computer models (time scales of minutes to days and spatial scales <2 km) suggests that fish movement behavior in rivers is frequently governed by responses to one or more of the following hydrodynamic features: (1) flow direction (i.e., rheotaxis), (2) flow velocity magnitude, (3) turbulence, and (4) depth, plus (5) the integration of information over recent time periods (i.e., memory/experience). However, the lack of consistent modeling approaches, infrequent assessment of each response in isolation and combination, and a focus on a limited number of species means the generality of these responses is uncertain. We use a computer model, specifically a pattern-oriented modeling approach incorporating individual based models (IBMs), to apply responses to the four hydrodynamic features plus memory/experience in different combinations to study their value for reproducing the movement of an infrequently modeled species and lifestage, upriver migrating adult sea lamprey, Petromyzon marinus . The study site was the region downstream of the Sault Ste. Marie lock and dam complex located between Canada and the U.S.A on the St. Marys River joining Lake Superior and Lake Huron. Our analysis indicates that rheotaxis and a response to velocity magnitude as well as recent past experience improve sea lamprey spatio-temporal movement prediction compared to other, simpler forms of modeled behavior. Sea lamprey movement is also biased toward lower levels of turbulence (e.g., turbulent kinetic energy) or its precursor (i.e., the spatial gradient in water speed). A response to water depth was not found to be important, but the modeled domain was two-dimensional which limited our assessment. As similar responses to hydrodynamic features are found in very different fish, commonalities appear to underlie river navigation across a range of species and life stages that share the goal-oriented behavior of upriver and downriver movement. The systematic approach of our analysis highlights the accuracy trade-offs of each response, individually and in combination, that often accompany alternative behavioral formulations in a computer model of fish movement. The model structure provides a framework to which future findings from the analyses of additional species in different contexts can be added.

Sault Ste. Marie lock and dam complex in the St. M↗

USGS2025

Greater sage-grouse seasonal habitat associations: A review and considerations for interpretation and management applications

Habitat features needed by wildlife can change in composition throughout the year, particularly in temperate ecosystems, leading to distinct seasonal spatial-use patterns. Studies of species-habitat associations therefore often focus on understanding relationships within discrete seasonal periods with common goals of prediction (e.g., habitat mapping) and inference (e.g., interpreting model coefficients). Across the range of the greater sage-grouse ( Centrocercus urophasianus ) of western North America, the increasing use of high-frequency tracking devices has led to a surge in habitat association studies covering multiple temporal periods and spatial extents. We reviewed the literature for seasonal habitat association studies corresponding to the second and third orders of selection (Johnson 1980). Our objectives were to summarize the methodological approaches used to estimate habitat associations to aid understanding in cross-study comparisons and identify common habitat features reported as selected or avoided within different seasonal periods. We reviewed 71 second- and third-order studies published from 2007–2023 that evaluated covariates collected in a geographic information system (GIS) and modeled probability of selection or intensity of use. The most common study design evaluated a single level of selection (third-order) and was multi-scale (i.e., covariates were measured at varying spatial grains). The most common model approach estimated habitat associations using resource selection functions (RSFs) fit with logistic regression. Studies mostly focused on the breeding periods and winter, but all seasons throughout the annual cycle were covered. There was clear support for selection of sagebrush and avoidance of trees and rugged terrain across seasons, and strong selection of mesic conditions in summer. However, habitat associations for most covariates were mixed, with proportionally equivalent selection and avoidance reported, even within the same seasons. Different factors hampered cross-study comparisons, including variation in study design, but additional contributors likely included important context-dependent habitat associations, such as functional responses to changing habitat availability. We suggest collaborative studies leveraging multiple datasets can help improve seasonal habitat inference by removing the effects of variable study designs.

Journal of Wildlife Management↗

USGS2025

Sea Lamprey control reduction during the COVID-19 pandemic corresponds to rapid increase in Sea Lamprey abundance

The Sea Lamprey Petromyzon marinus control program in the Laurentian Great Lakes is one of the longest-running and most successful invasive species suppression programs in the world. Although several techniques are used to suppress Sea Lamprey, the control program relies heavily on regular application of lampricide to kill stream-dwelling larvae. The COVID-19 pandemic disrupted lampricide application from 2020 to 2022, which provided a unique opportunity to test how Sea Lamprey populations and wound counts on fishes would respond. We evaluated the consequences of decreased control effort at a basin-wide level using standard control program metrics and through a focused analysis of multispecies wounding in Lake Ontario, which experienced the greatest disruption in Sea Lamprey control. The reduction in control effort corresponded to increased basin-wide adult Sea Lamprey abundance but was only weakly associated with Lake Trout Salvelinus namaycush wounding. However, the novel multispecies wounding rate metric calculated for Lake Ontario increased and was consistent with observations by anglers and managers regarding a sharp increase in Sea Lamprey abundance following reduced effort. Ultimately, our research highlights that consistent treatment is critically important for preventing damage stemming from Sea Lamprey and that reductions in suppression could quickly lead to a resurgence in abundance.

Great Lakes↗

USGS2025

Retrospective stepwise prioritization of chemicals detected in Great Lakes tributaries (2008–2018)

Through the U.S. Great Lakes Restoration Initiative, a 10-year, multiagency chemical monitoring effort was undertaken across the Great Lakes. In this effort, 586 chemicals were monitored and 334 were detected in grab/composite water samples. To help inform potential future actions, a stepwise prioritization framework was used to identify compounds for which publicly accessible water quality guidelines or effects information suggested there was potential aquatic ecotoxicity. Because water quality guidelines were only available for some chemicals, this framework used apical toxicity data collated from publicly accessible databases (e.g., the ECOTOXicology Knowledgebase) and alternative data, including literature-derived non-apical effect concentrations, in vitro bioactivities from high-throughput screening, and modeled ecotoxicity. To account for the diverse levels of confidence in these data, chemicals were prioritized within specific action categories, which suggested potential management or experimental activities that may be considered based on the types of data available for each compound. Overall, 11 detected chemicals were identified as high priority in different action categories. This included four chemicals prioritized for environmental management or targeted risk assessment, three chemicals prioritized for effects-based monitoring, one chemical prioritized for apical effects assessment, and three chemicals targeted for non-apical effects evaluation. This framework also identified 164 low-priority chemicals, among which more than 50% were prioritized based on water quality guidelines or apical effect concentrations (thus could be considered low priority for future risk assessment or management activities). Results aim to help regulatory agencies, environmental managers, and other stakeholders focus available resources on carrying out monitoring, experimental, and risk assessments for the chemicals that display the greatest potential to adversely impact Great Lakes ecosystems.

Great Lakes↗

USGS2025

Leveraging invasive mussel contaminant survey data for stepwise prioritization of chemicals of potential concern in the Great Lakes basin

Historical and ongoing anthropogenic activities coupled with advancements in analytical techniques have led to the detection of large numbers of contaminants in the Laurentian Great Lakes. Consequently, identifying and prioritizing chemicals likely to cause ecological harm represents a challenge for natural resource managers. Previous prioritization efforts have focused on contaminants in sediment, water, and passive samplers, which may not be representative of compounds that bioaccumulate in aquatic organisms. Consequently, this study adopted a stepwise method to prioritize chemicals of potential concern detected in dreissenid mussels from samples collected across the Great Lakes from 2009–2018. The stepwise method considered environmental fate, detection frequency, and exceedance of toxicity quotients based on ecotoxicological effect concentrations. Overall, 153 compounds out of 267 analyzed were detected in dreissenid mussels, 47 of which had water quality effect concentrations, 56 had apical effect concentrations (Tier 1 ECOTOX or apical screening), 17 had nonapical effect concentrations (Tier 2 ECOTOX, Cytotoxic Burst, and ToxCast) and 33 had estimated effect concentrations (quantitative structure-activity relationship, estimated screening, and pharmacological potency). Of the compounds with water quality effect concentrations, nine were designated as high priority, including the herbicide atrazine and five polycyclic aromatic hydrocarbons that were previously identified as potentially hazardous within other matrices. Similar contaminants were identified as high priority in a related study of native unionid mussels in the Great Lakes. A total of 27 compounds were low priority, suggesting that these contaminants do not warrant further action based on this dataset. Overall, these findings will facilitate the development of management strategies to mitigate the effects of contaminants on aquatic organisms within the Great Lakes.

Great Lakes basin↗

USGS2025

Evaluating drought risk of the Red River of the North Basin using historical and stochastic streamflow upstream from Emerson, Manitoba

Drought and its effect on streamflow are important to understand because of the potential to adversely affect water supply, agricultural production, and ecological conditions. The Red River of the North Basin in north-central United States and central Canada is susceptible to dry conditions. During an extended drought, streamflow conditions in the Red River of the North may become inadequate to support existing water supply needs in the basin for agriculture, industry, human use, and aquatic life. To understand potential future low-streamflow conditions in the Red River of the North Basin, the U.S. Geological Survey, in cooperation with the International Joint Commission, North Dakota Department of Water Resources, Red River Joint Water Resource District, and Red River Watershed Management Board, developed a water-balance model of the Red River of the North Basin upstream from Emerson, Manitoba, Canada, and coupled the model with stochastic weather inputs to simulate possible future low-streamflow conditions. Historical changes in low-streamflow conditions were characterized across the Red River of the North Basin using multiple change-point analysis for 12 streamgages. Across these stations, significant change-point years in 1943 and 1994 marked increases in the magnitude of low-streamflow conditions. During 1920–2015, conversion of primary land (not affected by human use) to agricultural and secondary land was followed by a conversion from smalls grains to corn and soybeans as the dominant crop type. From land-use analysis, 1940–2000 was determined to have relatively stable land use and therefore was used as the calibration period for the water-balance model. A deterministic water-balance model was developed for the Red River of the North Basin upstream from Emerson, Manitoba. The water-balance model was calibrated with data from 37 U.S. Geological Survey streamgages for 1940–2000 and verified using data for 2001–15. The calibrated water-balance model simulated streamflow distributions that mirrored the seasonal patterns of the observed mean monthly streamflow and the standard deviation of the monthly streamflow data, especially during the fall and winter months when streamflow was lowest. For the verification period, during the low-streamflow months of December through January, the difference between simulated and observed data was similar to the calibration comparison and successfully reproduced seasonal trends in the distribution of streamflow, even when using weather data that were outside the calibration period. To determine the future risk of low-streamflow conditions in the Red River of the North Basin, a block-bootstrap method was used to generate multiple possible future climates. These stochastically generated weather time series were then input to a water-balance model to simulate a distribution of possible streamflows. Three sets of experiments were performed, with each experiment containing a set of scenarios. The first set of experiments from the stochastic streamflow model were designed to investigate how changes in reservoir management would affect the distribution of low streamflow. Relative to scenario 1 (present-day [2023] reservoir operation), scenario 2 (no reservoir operation) shifted the low-streamflow frequency curves downward, reducing the annual minimum monthly streamflow for the Emerson subbasin. Subbasins were defined by the contributing area upstream from a selected streamgage station. Relative to scenario 1, scenario 3 (regulated streamflow with an increased reservoir capacity of 10 percent) shifted the low-streamflow frequency curves upward for the Emerson subbasin. The magnitude of this upward shift, caused by increased reservoir capacity, was lower than the magnitude of the shift caused by the absence of the reservoirs, which indicates that the streamflow was most affected when the reservoirs were first constructed. The second set of experiments from the stochastic streamflow model included two scenarios that were performed to better understand how the Red River of the North Basin responds to long periods of low or high precipitation. The results indicate that the model consistently overestimated streamflow, but the relative change between a wet and dry climate state of simulated streamflow distribution reasonably matched the relative change of historical streamflow. Across the subbasins, the model was most accurate for low-streamflow conditions associated with nonexceedance probabilities between 20 and 40 percent. The third set of experiments from the stochastic streamflow model were done to investigate low-streamflow response across the basin to several drought events. Low-end streamflow was reduced when the basin was exposed to a drought, and the magnitude of the reduction increased with longer or more intense droughts. Compared to the low-intensity drought scenarios, the range of percent reductions (as indicated by the interquartile range) was larger for the high-intensity drought scenarios for all subbasins, and the subbasins of Grand Forks and Emerson had a smaller range of reductions compared to the other three subbasins. The larger drainage area—combined with the large contribution of the Red Lake River and several other Minnesota tributaries that generally experience wetter climate conditions—upstream from the Emerson and Grand Forks subbasins may contribute to the smaller range in reductions under the high intensity scenarios. Comparison of the percent reduction in low-end streamflow among subbasins also indicated that the effects of drought duration and intensity could be cumulative. Combining factors of time and intensity produced a larger reduction in streamflow than when each effect was isolated. The array of drought scenarios can be used to determine how a subbasin would respond to multiple possible future conditions. Based on climate predictions, the drought scenario that best matches a future anticipated drought scenario can be used to estimate a low streamflow response for a given subbasin.

Manitoba, Minnesota, North Dakota↗

USGS2025

Freshwater gastropod (Mollusca: Gastropoda) assemblages, habitat, and the first detection of an invasive gastropod species in two large, dreissenid-influenced, connecting rivers

Native freshwater gastropods are a highly diverse and imperiled group of mollusks in North America and are influenced by a growing number of problematic invasive species. Consequently, there has been an increased need for understanding aquatic gastropod assemblages throughout North America to implement conservation and management strategies. In the Laurentian Great Lakes, gastropod surveys have been sparse, and most surveys have focused on invasive species. To investigate gastropod assemblages in two large connecting rivers of the Great Lakes, the Detroit and St. Clair rivers, benthic surveys were conducted in 2019 and 2021. Sites in the Detroit River (n = 56) and the St. Clair River (n = 51) were surveyed using petite PONAR grabs from which gastropod shells were identified and quantified to family or a group of two combined families. In both the Detroit and St. Clair rivers, the gastropod family Pleuroceridae (37 % and 56 % total composition, respectively) and combined families Amnicolidae + Hydrobiidae (42 % and 23 % total composition, respectively) contributed the most to overall gastropod composition. Invasive Potamopyrgus antipodarum shells were identified at 4 (7 %) Detroit River sites and 10 (20 %) St. Clair River sites and represent the first documented occurrence in the Detroit River. Although this study was limited to quantifying densities based on shells and cannot assume live-collected snail densities, these results provide a baseline knowledge of the gastropod assemblages and habitat use in these two large river systems which can be used to implement conservation and management strategies.

Detroit River, St. Clair River↗

USGS2025

Range-wide ecology, conservation, and research needs for yellow lampmussel (Lampsilis cariosa)

The freshwater mussel yellow lampmussel ( Lampsilis cariosa ) is declining throughout its range along the Atlantic Slope of the eastern United States and Canada, and the species is a target for proactive conservation to avoid federal listing. This paper synthesizes information about the ecology (physiology and life history, host fishes, and habitat), species distribution, genetics, and threats to L. cariosa . Identified threats include climate change, habitat alteration, and invasive species, dependent on location. We outline 16 emergent research and conservation management needs based on literature review and discussion with stakeholders (state and federal mussel biologists, researchers, and tribal groups). These needs range from research on the basic physiology and behavior of the species, to creating standardized protocols for surveys and DNA sampling, to ultimately developing a range-wide species conservation and restoration plan. Addressing these information gaps and incorporating the findings into future management may facilitate the implementation and success of large-scale restoration and conservation initiatives such as habitat protection and reintroduction of L. cariosa to historical locations.

Hydrobiologia↗

USGS2025

What is a specialist? Quantifying host breadth enables impact prediction for invasive herbivores

Herbivores are commonly classified as host specialists or generalists for various purposes, yet the definitions of these terms, and their intermediates, are often imprecise and ambiguous. We quantified host breadth for 240 non-native, tree-feeding insects in North America using phylogenetic diversity. We demonstrated that a partitioning of host breadth: (1) causes 67% of non-native insects to shift from a generalist to specialist category, (2) displays a reduction in host breadth from the native to introduced range, (3) identifies an inflection point in a model predicting the likelihood of non-native insect ecological impact, with a corresponding change in behaviour associated with specialists versus generalists, and (4) enables three models for strong prediction of whether a non-native forest insect will cause high impacts. Together, these results highlight the primacy of how herbivore host recognition and plant defences mediate whether novel host interactions will result in high impact after invasion.

Ecology Letters↗

USGS2025

Sensitivity of benthic biota and toxicity of cadmium, cobalt, copper, nickel, lead, and zinc mixtures in Washington, United States, and British Columbia, Canada

Relative sensitivities and responses of juvenile white sturgeon ( Acipenser transmontanus ), Hyalella azteca , two families of mayfly (Ephemerellidae, Heptageniidae), one family of caddisfly (Brachycentridae), and a natural community of benthic macroinvertebrates (BMI) to multiple metals are predicted using previously collected laboratory and field samples and a metal mixture model. Biological responses in single metal exposures are used to parameterize toxicity functions, which include accumulations of hydrogen and selected metals on biological receptors, intrinsic potencies of hydrogen and metals, sensitivities of organisms, and times of exposure. The model then is used to predict responses in multiple metal laboratory exposures and field-collected porewater. The following sensitivity sequence in porewater was determined based on endpoints of survival or total abundance: juvenile white sturgeon greater than (>) Ephemerellidae family > Hyalella azteca > Heptageniidae family about equal to (~) benthic macroinvertebrate community > Brachycentridae family. The fraction of porewater samples that are predicted to have adverse impacts on benthic biota (20-percent or greater negative response) depends on organism sensitivities and metal toxicities, and ranges from 44 to 48 percent for juvenile white sturgeon, 23 to 26 percent for the Ephemerellidae family, 16 to 22 percent for Hyalella azteca , 5 to 8 percent for the Heptageniidae family and BMI community, and 0 percent for the caddisfly family. The most toxic porewater in the upper Columbia River Basin (UCR) is at the backwater bar site at Deadmans Eddy and China Bend. The model also indicates that the element responsible for the most toxic conditions in UCR porewater is copper for all organisms, except Hyalella azteca and the metal-insensitive Brachycentridae family. Copper and lead result in the most toxic conditions for Hyalella azteca . This approach and results can aid in assessing metal toxicity and its potential risk to aquatic biota in ecosystems impacted by historical mining activities.

British Columbia, Washington↗

USGS2025

A high-resolution 3-D P-wave velocity structure of the south-central Cascadia subduction zone from wide-angle shore-crossing seismic refraction data

This study addresses a significant gap in understanding the features of the south-central Cascadia subduction zone, a region characterized by complex geologic, tectonic, and seismic transitions both offshore and onshore. Unlike other segments along this margin, this area lacks a 3-D velocity model to delineate its structural and geological features on a fine scale. To address this void, we developed a high-resolution 3-D P-wave velocity model using active source seismic data from ship-borne seismic shots recorded on temporary and permanent onshore seismic stations and ocean-bottom seismometers. Our model shows velocity variations across the region with distinct velocity-depth profiles for the Siletz, Franciscan, and Klamath terranes in the overlying plate. We identified seaward dipping high-velocity static backstops associated with the Siletz and Klamath terranes, situated near the shoreline and further inland, respectively. Regions of reduced crustal velocity are associated with crustal faults. Moreover, there is significant along-strike depth variation in the subducting slab, which is about 4 km deeper near the thick, dense Siletz terrane and becomes shallower near the predominantly less-dense Franciscan terrane. This highlights a sudden tectonic and geologic transition at the southern boundary of the Siletz terrane. Our velocity model also indicates slightly increased hydration, though still minimal, in both the oceanic crust and the upper mantle of the subducting plate compared to other parts of the margin.

British Columbia, California, Oregon, Washington↗

USGS2025

A fire deficit persists across diverse North American forests despite recent increases in area burned

Rapid increases in wildfire area burned across North American forests pose novel challenges for managers and society. Increasing area burned raises questions about whether, and to what degree, contemporary fire regimes (1984–2022) are still departed from historical fire regimes (pre-1880). We use the North American tree-ring fire-scar network (NAFSN), a multi-century record comprising >1800 fire-scar sites spanning diverse forest types, and contemporary fire perimeters to ask whether there is a contemporary fire surplus or fire deficit, and whether recent fire years are unprecedented relative to historical fire regimes. Our results indicate, despite increasing area burned in recent decades, that a widespread fire deficit persists across a range of forest types and recent years with exceptionally high area burned are not unprecedented when considering the multi-century perspective offered by fire-scarred trees. For example, ‘record’ contemporary fire years such as 2020 burned 6% of NAFSN sites—the historical average—well below the historical maximum of 29% sites that burned in 1748. Although contemporary fire extent is not unprecedented across many North American forests, there is abundant evidence that unprecedented contemporary fire severity is driving forest loss in many ecosystems and adversely impacting human lives, infrastructure, and water supplies.

Nature Communications↗

USGS2025

Combining multisite tsunami and deformation modeling to constrain slip distributions for the 1700 C.E. Cascadia earthquake

A major earthquake ruptured the Cascadia subduction zone (CSZ) on 26 January 1700. Key paleoseismic evidence associated with this event include tsunami deposits, stratigraphic evidence of coastal coseismic subsidence, written Japanese records of a tsunami unaccompanied by earthquake shaking, and margin‐wide turbidites found offshore and in lacustrine environments. Despite this wealth of independent clues, important details about this event remain unresolved. Dating uncertainties do not conclusively establish whether the proxies are from one earthquake or a sequence of them, and we have limited knowledge of the likely slip distributions of the event or events. Here, we use a catalog of 37,500 candidate synthetic ruptures between M w 7.8 and 9.2 and simulate their resulting coseismic deformation and tsunami inundation. Each model is then compared against estimated Japan tsunami arrivals, regional coastal subsidence records, and local paleotsunami deposits mapped at six different coastal marshes and one coastal lake along the CSZ. We find that seven full‐margin ruptures with a median magnitude of M w 9.1 satisfy all three constraints. We favor one M w 9.11 model that best matches all site paleoseismic observations and suggests that the Cascadia megathrust slipped up to ∼30 m and must have shallow geodetic coupling. We also find that some sequences composed of three or four ruptures can still satisfy the observations, yet no sequences of two ruptures can. Sequences are differentiated into three groups based on whether they contain a mainshock rupture located in the south (>44° N) or further north. All sequences contain unruptured portions of the megathrust and most contain mainshocks with peak slip above 40 m. The fit of the geologic evidence from sequences is poor in comparison to single‐event models. Therefore, sequences are generally less favored compared to full‐margin events.

British Columbia, California, Oregon, Washington↗

USGS2025

Lake Superior fish community and fisheries, 2001–2022: An era of stability

Lake Superior is the least anthropogenically impacted of the Laurentian Great Lakes ecosystems, yet dramatic changes to the fish community are evident. Previous published works chronicled those changes and the efforts to rehabilitate the fish community through the year 2000. Here, we review through the year 2022, where post-rehabilitation stability was driven by lean lake trout ( Salvelinus namaycush namaycush) as the most abundant piscivore in nearshore waters, siscowet lake trout ( Salvelinus namaycush siscowet) as the most abundant piscivore in offshore waters, and a healthy, intact assemblage of native prey species, which created ecological redundancies and helped stabilize the food web. Stocking of non-native salmonines was reduced 74%, and populations of Chinook salmon ( Oncorhynchus tshawytscha) and coho salmon ( Oncorhynchus kisutch) were maintained through natural reproduction. Despite reduced stocking, yield from recreational fisheries was stable. Likewise, developments in population modeling led to evaluations and refinement of management strategies that helped create stability for lake trout, lake whitefish ( Coregonus clupeaformis ), and cisco ( Coregonus artedi ) fisheries. With lake trout rehabilitation achieved, focus shifted toward rehabilitation of native brook trout ( Salvelinus fontinalis ), lake sturgeon ( Acipenser fulvescens ), and walleye ( Sander vitreus ). Despite continued control efforts, sea lamprey ( Petromyzon marinus ) abundance increased considerably, and estimates of fish killed by lampreys averaged 2.65 million kg annually. Environmental changes have benefited sea lampreys and fostered thermal habitats more suitable to non-native organisms, posing new challenges for managers and researchers. Nevertheless, the post-rehabilitation stability in the contemporary fish community will help provide resilience to future perturbations in the ecosystem.

Lake Superior↗

USGS2025

Mountain sentinels in a changing world: Review and conservation implications of weather and climate effects on mountain goats (Oreamnos americanus)

Climate change is occurring at an accelerated rate in high-elevation alpine and mountain ecosystems. Cold-adapted, mountain species are at risk due to forecasted change and knowledge is needed to respond to current and future conservation challenges. Mountain goats ( Oreamnos americanus ) are an iconic species of North American mountain cultures and landscapes, and due to specialized adaptations for life in cold, mountainous environments they are particularly sensitive to changes in weather and climate. As sentinels of change in alpine ecosystems, the study of mountain goats offers insight into the ecological effects and conservation challenges associated with climate change in these sensitive and biodiverse environments. Here, we synthesize existing knowledge about how climate change is expected to influence environmental conditions experienced by mountain goats and associated mechanistic changes to behavior, nutritional ecology, demography, health, and interspecific interactions. In many instances, climate change effects are likely to be negative and additive to existing threats (such as human disturbance, hunting, disease, predation) though benefits are expected in some cases. Changes in climate and mountain environments will necessitate re-examination and modification of population monitoring, management, and conservation strategies. Specifically, spatiotemporal (and other) aspects of monitoring and management may need to be adjusted to accommodate emerging and novel conservation challenges. Yet, key data and knowledge gaps remain and should be addressed to advance conservation and decision-making capabilities. For mountain goats and similarly climate-sensitive alpine herbivores, effective conservation will ultimately benefit from collaborations among diverse networks guided by well-planned, strategic visions focused on common ground – namely the resiliency and persistence of culturally and ecologically significant mountain species and the alpine environment they inhabit.

Alaska, Alberta, British Columbia, Idaho, Montana,↗

USGS2025

Wetland hydrologic dynamics and duck productivity are declining in the Prairie Pothole Region, and they are linked

The Prairie Pothole Region (PPR) of North America is a globally important area hosting >50 % of North America’s breeding ducks. Ducks in the PPR depend on wetlands and grasslands which have experienced accelerated losses in extent and quality due to agriculture. While other bird populations have declined, duck abundance reached record highs recently (2013–2017). We explored this discontinuity by examining monitoring data for trends in pond numbers (wetlands with ponded water) and interannual dynamics (water-level dynamics indexed by interannual change in pond numbers) and how those factors influenced duck productivity in the PPR during 1976–2019. Over time, pond numbers increased but their interannual dynamics declined, indicating stabilization of an ecosystem evolved with a dynamic climate. Our models accounted for 67 and 71 % of variation in productivity of PPR-obligate gadwall ( Mareca strepera ) and redheads ( Aythya americana ), respectively. Breeding productivity of these sentinel species was positively correlated with pond abundance and dynamics, and systematically declined. Accordingly, our analyses revealed sensitivity of breeding ducks to systematic change in the PPR previously obscured by increasingly abundant pond numbers. Interannual pond dynamics improved duck productivity and pond dynamics have declined indicating a de facto 44-year decline in duck productivity which is likely driven by water-level stabilization decreasing quality of brood-rearing wetlands. Residual temporal effects indicated that productivity has also declined for other reasons, such as agricultural land use changes. While mechanisms behind these correlations are speculative, they demonstrate the importance of further understanding land use and climate changes in the PPR for conservation of these important species and ecosystems.

Alberta, Iowa, Manitoba, Minnesota, Montana, North↗

USGS2025

Decision analysis of Integrated Pest Management: A case study on invasive sea lamprey in the Great Lakes Basin

Integrated Pest Management (IPM) provides a powerful framework for addressing threats to human well-being caused by nuisance species including invasives. We examined the hypothesis that adaptive management could erode barriers to IPM implementation by developing a decision-analytic adaptive management framework for invasive sea lamprey ( Petromyzon marinus ) IPM in the Laurentian Great Lakes of North America. The framework addressed objectives associated with coordinating multiple sea lamprey control actions at the regional scale and objectives associated with internal validity of control actions. We reduced the scope of possible management actions by orders of magnitude to the set of 6432 alternatives expected to be both socially acceptable and technically feasible. Using utility theory, we identified the management actions that optimized expected utility for all possible objective weighting schemes that considered tradeoffs between maximizing learning about control tactic efficacy and minimizing cost to the IPM program. Sensitivity analyses revealed that assumptions about the social acceptability of deploying electric weirs to control invasive sea lamprey influenced selection of the optimal control action, suggesting that resolving this source of uncertainty through iterative application of the framework may lead to improved sea lamprey control outcomes. Overall, we found that adaptive management enabled learning processes useful for overcoming barriers to IPM of invasive sea lamprey. It formalized learning about sea lamprey control tactic efficacy as an objective of the IPM institution, questioned previously held assumptions about what constitutes a viable control strategy, and enabled a management experiment with temporal and spatial replication.

Michigan, Ontario, Wisconsin↗