Geology topics

Research about Minnesota

Source-linked reports with geographic coverage including Minnesota.

At least 37 records · Page 2Linked to original sources

USGS2025

Exposure to ultraviolet radiation induces escape hatching of Cisco (Coregonus artedi) embryos

Cisco (Otoonapii in Ojibwe; Coregonus artedi Lesueur, 1818), is a widely distributed stenothermic freshwater fish whose embryos typically incubate under ice and in the dark. We used Cisco as a model organism for testing the potential of UV-induced escape hatching behaviour. Owing to reduced ice cover and increased water transparency in north temperate lakes, these experiments provide insights into the resilience of coregonine embryos if exposed to ultraviolet radiation (UV-B; 280–320 nm). Eyed Cisco embryos were exposed to artificially sourced UV-B through a series of experiments that measured the hatching rate and fitness (heart rate and pigmentation pattern) 2 days after hatching and under cold [6.6°C] and warm [8.6°C] conditions. These experiments supported an extension of the escape hatching behaviour hypothesis, whereby UV-B exposure induced earlier (ca 30 days) and more punctuated hatching of Cisco embryos, independent of an increase in water temperature. UV-B exposure produced more larvae with irregular pigmentation patterns and reduced heart rates (by about 20%) – both of which could be indicative of reduced fitness. UV-induced escape hatching adusts the fundamental framework in which we characterise fish embryo resilience to increased UV-B exposure and the potential consequences of reduced ice cover. Earlier hatching from UV-B exposure could increase the recruitment bottleneck of these fish by reducing survivorship of the post-hatched larvae.

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USGS2025

Groundwater budget for the surficial aquifer surrounding Lake Nokomis, Minneapolis, Minnesota

During prolonged periods of above-average precipitation, rising groundwater levels have the potential to cause damage to and interfere with underground infrastructure and building foundations. To understand the relations between precipitation and groundwater in the vicinity of Lake Nokomis, the U.S. Geological Survey, in collaboration with the University of Minnesota, quantified five components of the groundwater budget: groundwater recharge, change in surficial aquifer storage, surficial aquifer groundwater discharge to Lake Nokomis, groundwater evapotranspiration, and groundwater discharge to underlying bedrock aquifers. Field data, geologic records, and empirical calculation methods were used to quantify groundwater budget components for April 2023 through April 2024. Lake water budget data indicate that Lake Nokomis is a flowthrough system during periods with no outflow through the weir, with groundwater inputs equal to outputs. Roughly 40 percent of precipitation that fell in the study area was added to the surficial aquifer as recharge. Uncertainty in the vertical hydraulic conductivity resulted in wide-ranging estimates (spanning three orders of magnitude) of water discharging from the surficial aquifer to the underlying bedrock aquifer. Drought conditions persisted for the duration of this study and were not representative of the conditions that motivated this study. This study is a start towards understanding relations between precipitation, Lake Nokomis levels, and groundwater levels that could affect local underground infrastructure.

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USGS2025

Suspended sediment and bedload transport along the Main and South Branches, Wild Rice River, northwestern Minnesota, 1979 through 2023

The geologic history and anthropogenic modifications of Minnesota’s Wild Rice River have caused major morphological adjustments, which induce erosion and excess fluvial sediment transport. The excess sediment deposits in the lower Wild Rice River, exacerbating flooding. To help mitigate these problems, the Wild Rice Watershed District has future plans to implement a river restoration on the lower Wild Rice River. The Wild Rice Watershed District collaborated with the U.S. Geological Survey to measure and analyze sediment transport along the Wild Rice River’s Main and South Branches to assess any potential changes in sediment transport among sites and time periods. Time differencing results indicated that all suspended-sediment constituents showed a significant difference between the two sampling periods at one South Branch site but not at the Main Branch site. Piecewise regression analysis better matched the suspended-sediment constituents transport process at most sites by differentiating no relation between suspended-sediment constituents at lower streamflows and a positive relation at higher streamflows at most Wild Rice River sites. Five of the sites showed elevated sediment transport with increasing streamflow. In contrast, the site farthest downstream showed a negative relation with increasing streamflow, indicating that that the lower Wild Rice River is supply limited and deposition is likely occurring upstream and (or) near the site. Overall, the uncertainty in results indicates the complexity of sediment transport in a river when using streamflow as the sole explanatory variable and suggests a need for multisite, multiyear, and multifaceted data.

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USGS2025

Variable phenology but consistent loss of ice cover of 1213 Minnesota lakes

Lake ice cover is declining globally with important implications for lake ecosystems. Ice loss studies often rely on small numbers of lakes with long-term data. We analyzed variation and trends in ice cover phenology from 1,213 lakes over 74 years (1949-2022) in Minnesota (USA), during which ice cover duration declined at a rate of 2 days per decade (14 days total) and became more variable. Despite variation in phenology, just 10-20% of lakes differed from statewide phenological trends. Accounting for synchronous annual variation and estimating trends over long time periods (e.g., >40 years) were critical for obtaining robust estimates of ice loss. The constant rates estimated here were consistent with recent global estimates (1.7-1.9 days per decade) and suggest that, even if present, accelerating rates of ice loss would be difficult to detect in the midst of shorter-term periods of warming and increasing variability.

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USGS2025

Assessment of effects of channelization mitigation alternatives of Stoney Brook, Carlton and St. Louis Counties, Minnesota

The U.S. Geological Survey, in cooperation with the Fond du Lac Band of Lake Superior Chippewa (FDLB), studied the effects of channel modification alternatives on lake levels and floodplain inundation in the Stoney Brook watershed in northeast Minnesota. Northern wild rice ( Zizania palustris ), also referred to as manoomin by the Ojibwe/Chippewa people, is a natural and cultural resource to the FDLB and is sensitive to water levels and rates of water-level changes, particularly during the early stages of growth. Drainage ditches constructed in the early 1900s in the Stoney Brook watershed lowered lake-water levels, caused greater fluctuations in the lakes, and created a loss in wetland coverage. The FDLB is committed to minimizing large fluctuations of the lakes with natural wild rice production in the Stoney Brook watershed and restoring a more natural hydrology to Stoney Brook. The hydrologic response of these lakes and floodplain storage to simulated channel modification alternatives were examined. Hydrologic and hydraulic models were developed for the watershed and calibrated to historical rainfall events. The models used probabilistic frequency rainfall events of 24-hour duration for 1-, 2-, 5-, and 10-year annual recurrence intervals (100-, 50-, 20-, and 10-percent annual exceedance probability) to simulate watershed management scenarios with existing and alternative conditions. The hydraulic model outputs for peak flows, volume accumulation, water levels, and inundation duration and depths were assessed to quantify the effects of the channel modification alternatives. The channel modification alternatives were simulated with four different terrain conditions: existing conditions, bank spoil breach, original channel reconnection, and original channel reconnection with bank spoil breach. Hydrologic characteristics from six distinct areas were used in the model to evaluate the effects from the channel modification alternatives. The simulated results of two lakes in which wild rice was planted demonstrated that the lakes would take longer to draw down following an event with the channel modification alternatives compared to existing conditions with little change to peak water-surface elevations. The alternatives provided minor to no increases in flows or conveyances at the downstream reference location at Pine Drive bridge. The restored floodplain locations had increased flows and conveyances for the channel modification alternatives that could be considered substantial when compared to flows with existing conditions. The inundation extent, duration, and water-depth distribution were assessed within selected floodplain areas. Generally, the channel modification alternatives produced increases in the higher depth (3–4 and greater than 4 feet) and duration (10–14 and greater than 14 days) categories for these areas, which may be beneficial to increases in wetland coverage and floodplain storage.

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USGS2025

Peak streamflow trends in Minnesota and their relation to changes in climate, water years 1921–2020

This report chapter summarizes the effect of hydroclimatic variability of annual peak streamflow in Minnesota and is part of a larger U.S. Geological Survey multistate study to assess potential nonstationarity in annual peak streamflows across the Midwest. Spatial and temporal patterns were examined for nonstationarity in annual peak streamflow, daily mean streamflow, and modeled climatic data in four analysis periods: (1) a 100-year period, 1921–2020; (2) a 75-year period, 1946–2020; (3) a 50-year period, 1971–2020; and (4) a 30-year period, 1991–2020. Upward trends in annual peak streamflow were detected in northwest to southeast and north to south directions. Downward trends in annual peak streamflow were detected in northeastern and southeastern areas. Trends in peak-flow timing indicated that peak streamflows are being detected later in the water year (the period from October 1 to September 30 designated by the year in which it ends) mainly in the southern areas and earlier in the water year mainly in the northern areas. Changes in climate data point to wetter conditions in southern areas and drier conditions in northern areas. Annual precipitation was determined to be increasing in a northwest to southeast direction and in the east. In contrast, some areas in the north and northwest indicated decreasing annual precipitation. Annual snowfall was determined to be decreasing except in the extreme northeast, where annual snowfall was determined to be increasing. Decreases in annual potential evapotranspiration were detected in the south, and increases were detected in the north. Annual soil moisture increased in southern areas and decreased in northern and eastern areas. The potential spatial and temporal nonstationarity violations detected in the four analysis periods have important implications for flood-frequency analysis and point to the need for guidance on how to incorporate nonstationarities into future flood-frequency analysis in Minnesota.

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USGS2025

Possible influence of water level management on nutrient flux in nearshore sediments of Kabetogama Lake, Minnesota, USA

Lake water level fluctuations are an important factor driving variation in many ecosystem processes. The nearshore sediments that are periodically exposed and re-inundated can develop distinct physical and chemical characteristics, especially in relationship to the organic matter content of the sediments and the particle size distribution. These sediment characteristics in turn can alter the flux of nitrogen (N) and phosphorus (P) from sediments into the water column when sediments are inundated. Here, we used intact sediment core experiments across a range of sediment inundation frequencies to estimate the effect of inundation frequency on sediment nutrient flux in Kabetogama Lake, Minnesota, USA. We observed associations between elevation or inundation frequency and some sediment characteristics, but in a structural equation model, inundation frequency and the sediment properties we measured were poorly related to inorganic nutrient flux. On the other hand, inundation frequency did have a moderate association with organic N and P flux from sediments, which could be due to decay of terrestrial organic matter that accumulates on exposed sediments. We used our parameterized structural equation model to estimate how three different water level management regimes employed over the past 50 years could influence organic N and P flux from sediments. The models suggested more recent water level management regimes reduced organic N and P flux by 9%–13% and 5.9%–9.8%, respectively. Nearshore sediment flux could sustain and influence harmful algal blooms that occur in this lake, and these fluxes could be influenced by water level management.

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USGS2025

Using machine learning in Minnesota’s StreamStats to predict fluvial sediment

A thorough understanding of fluvial sediment transport is essential for addressing key environmental issues such as aquatic habitat degradation, flooding, excess nutrients, and challenges with river restoration. Fluvial sediment samples are valuable for addressing these concerns, but their collection is often impractical across all rivers and timeframes of interest. In addition, previously used analytical and numerical methods have not allowed for the transfer of knowledge from sites that have data to sites that do not have data. To overcome this limitation, the U.S. Geological Survey developed machine learning models to predict suspended-sediment concentrations and bedload transport in Minnesota rivers that lack physical sediment data and integrated them into the U.S. Geological Survey StreamStats web application.

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USGS2025

Relatedness of white-tailed deer from culling efforts within chronic wasting disease management zones in Minnesota

In white-tailed deer ( Odocoileus virginianus ), closely related females form social groups, avoiding other social groups. Consequently, females infected with chronic wasting disease (CWD) are more likely to infect social group members. Culling has been used to reduce CWD transmission in high-risk areas; however, its effectiveness in removing related individuals has not been assessed. We analyzed 11 microsatellites and a mitochondrial DNA fragment to assess: (1) the genetic structure in white-tailed deer in Minnesota, USA and (2) the effectiveness of localized culling to remove related deer. For (1), we genotyped deer culled in 2019 and 2021 in three CWD management zones, and deer collected in between zones. For (2), we only included culled deer, defining “culled groups” as deer obtained in the same township-range-section and year. We compared mean relatedness among deer from the same culled group (intra-group relatedness) and among deer from different culled groups (inter-group relatedness). We did not find evidence of genetic structure, suggesting that an outbreak in any of the management zones could naturally spread to the others. Culling removed deer that were on average more related than expected by chance (intra-group relatedness > inter-group relatedness), and most highly-related deer were culled in the same bait site.

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USGS2024

Per- and polyfluoroalkyl substances in the Duluth, MN area: Exposure to and biomarker responses in tree swallows relative to known fire-fighting foam sources

Tree swallow nest boxes were deployed at sites proximal to two putative aqueous film forming foam (AFFF) sources in the Duluth, MN area, as well as along the St. Louis River and a reference lake for comparative purposes in 2019, 2020 and 2021. The two AFFF sites were the current Duluth Air National Guard Base (ANG) and the Lake Superior College Emergency Response Training Center. Between 13 and 40 per- and polyfluoroalkyl substances (PFAS), depending on year, were detected and quantified in tree swallow egg, nestling carcasses, and stomach contents. Assessments were made of oxidative stress and ethoxyresorufin-O-dealkylase activity in liver tissue, thyroid hormone levels in plasma and thyroid glands, DNA damage in red blood cells, and two measures of immune response (haptoglobin-like activity and immunoglobulin) in plasma of the nestlings. Additionally, other contaminants, such as polychlorinated biphenyls, legacy organochlorine pesticides, and trace elements, were assessed at sites with no previous data. Total egg PFAS concentrations at the ANG site and north of that site were 30–40 times higher than at the reference lake, while nestling PFAS concentrations were 10–15 times higher. In contrast, the St. Louis River sites had slightly, but non-statistically significant, elevated egg and nestling PFAS concentrations relative to the reference lake (2–5 times higher). One PFAS, perfluorohexane sulfonate (PFHxS), was higher, as a proportion of total PFAS, at sites with a known AFFF source compared to the reference lake, as well as compared to sites along the St. Louis River with mainly urban and industrial sources of PFAS. The ratio of total carboxylates to total sulfonates also distinguished between PFAS sources. There were few to no differences in biomarker responses among sites, and no association with PFAS exposure.

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USGS2024

Factors influencing larval coregonine spatial distribution in Lake Geneva (Europe) and Lake Superior (North America) during a single season near known spawning sites

Survival rate of the larval stage is an important driver of fish recruitment. To understand mechanisms regulating larval survival it is important to understand the relative importance of abiotic and biotic factors that shape larval spatial distributions. We studied larval Coregonus distributions in surface waters (surface to 1 m) by repeatedly sampling study sites in two lakes that varied greatly in trophic state and regional climate. We evaluated the importance of bathymetric depth, Julian Day, edible zooplankton densities (EZ, ind. L −1 ) and wind vectors on larval spatial distributions using generalized additive modeling. In both systems, larval counts declined in a negative exponential fashion with bathymetric depth, indicating shallow depths are critical nursery habitat. The north-south wind vectors and Julian Day (which was positively correlated with surface temperature) influenced larval distributions in Lake Geneva with larval counts related to both variables linearly, whereas the east-west wind vector and EZ were unimportant. Highest larval counts were during an offshore south wind and declined slightly with Julian Day. In Lake Superior, bathymetric depth and the east-west wind vector influenced larval distributions and were unrelated to EZ, Julian Day, and the north-south wind vector. Larval counts were highest when onshore southwest winds preceded sampling. Differences in how wind affected larval distribution (offshore vs. onshore) might be related to larval size with Lake Superior larvae considerably smaller (average length 12.9 mm vs. 15.9 mm); thus, more apt to be subjected to advection. Within coastal waters, Julian Day and wind vectors influence distributions, but their importance seemingly varies lake-to-lake.

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USGS2024

Restoration of common loon (Gavia immer) in Minnesota—2023 annual report

The Deepwater Horizon mobile drilling platform exploded on April 20, 2010. The resulting massive oil spill injured natural resources in the Gulf of Mexico, including wintering common loons ( Gavia immer ). We report on activities completed under the “Restoration of Common Loons in Minnesota” project in calendar year 2023, which was funded by the Open Ocean Trustee Implementation Group. In 2022, a subset of monitored breeding territories was identified as focal territories, which are sampling units for the study. The U.S. Geological Survey, in cooperation with the Minnesota Department of Natural Resources, monitored 98 common loon focal territories and an additional 43 nonfocal territories in 2023 across 56 study lakes in Minnesota. We collaborated with lake associations and private citizens to deploy 42 artificial nesting platforms within 44 focal treatment territories. The remaining 54 focal territories were controls. Territorial surveys were completed from May 8 to August 11, 2023, to evaluate occupancy, nest success, and chick survival. At least one nest attempt was observed in 31 of 44 treatment territories and a second nest attempt was observed after a failed initial attempt in 6 treatment territories. However, only one nest was on an artificial nesting platform in a treatment territory; the remaining nest locations were natural. At least one nest attempt was observed in 37 of 54 control territories, and a second nest attempt was observed after a failed initial attempt in 5 control territories. Chicks or other evidence of hatching were observed in 17 of 54 control territories and 17 of 44 treatment territories, with 1 of those successful treatment nests occurring on an artificial nesting platform. This report includes no formal analysis, but we plan to analyze data after collection of all field data in subsequent years.

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USGS2024

Predicting responses to climate change using a joint species, spatially dependent physiologically guided abundance model

Predicting the effects of warming temperatures on the abundance and distribution of organisms under future climate scenarios often requires extrapolating species–environment correlations to climatic conditions not currently experienced by a species, which can result in unrealistic predictions. For poikilotherms, incorporating species' thermal physiology to inform extrapolations under novel thermal conditions can result in more realistic predictions. Furthermore, models that incorporate species and spatial dependencies may improve predictions by capturing correlations present in ecological data that are not accounted for by predictor variables. Here, we present a joint species, spatially dependent physiologically guided abundance (jsPGA) model for predicting multispecies responses to climate warming. The jsPGA model uses a basis function approach to capture both species and spatial dependencies. We apply the jsPGA model to predict the response of eight fish species to projected climate warming in thousands of lakes in Minnesota, USA. By the end of the century, the cold-adapted species was predicted to have high probabilities of extirpation across its current range—with 10% of lakes currently inhabited by this species having an extirpation probability >0.90. The remaining species had varying levels of predicted changes in abundance, reflecting differences in their thermal physiology. Though the model did not identify many strong species dependencies, the variation in estimated spatial dependence across species suggested that accounting for both dependencies was important for predicting the abundance of these fishes. The jsPGA model provides a new tool for predicting changes in the abundance, distribution, and extirpation probability of poikilotherms under novel thermal conditions.

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USGS2024

Low rate of population establishment of a freshwater invertebrate (Gammarus lacustris) in experimental conservation translocations

Conservation translocations may be a useful tool for the restoration of declining freshwater invertebrates, but they are poorly represented in the literature. We conducted a before-after/control-impact (BACI) experiment to test the efficacy of conservation translocation for re-establishing abundant populations of the amphipod Gammarus lacustris , a declining species and wildlife food resource in depressional wetlands in the upper Midwest of the United States of America. Each study site ( n = 19) contained at least one treatment wetland receiving translocated G. lacustris from a local donor and one control wetland. We selected study wetlands based on a suite of wetland characteristics and randomly assigned recipient versus control treatment. Gammarus lacustris was detected post-translocation at only 2 of 22 recipient wetlands (1 of 19 sites). Overall, there was a statistical increase in G. lacustris density in recipient wetlands compared to controls; however, the results were of minimal biological significance due to being driven by a single site with low G. lacustris densities. Accordingly, our results suggest that future conservation translocations of amphipods might be successful if limited to recently restored wetlands or informed by a more complex habitat suitability model to differentiate dispersal limitations from habitat limitations. To develop such a model would involve identifying the fewest, most influential physical and biological factors (e.g. wetland size/structure, fish, aquatic vegetation, and water chemistry) from the numerous inter-related factors that correlate with the abundance of naturally occurring G. lacustris ; candidate wetlands to receive amphipods would be those for which the model predicts abundant G. lacustris but in which they do not presently occur.

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USGS2024

Infectivity of wild-bird origin Influenza A viruses in Minnesota wetlands across seasons

The environmental tenacity of influenza A viruses (IAVs) in the environment likely plays a role in their transmission; IAVs are able to remain infectious in aquatic habitats and may have the capacity to seed outbreaks when susceptible wild bird hosts utilize these same environments months or even seasons later. Here, we aimed to assess the persistence of low-pathogenicity IAVs from naturally infected ducks in Northwestern Minnesota through a field experiment. Viral infectivity was measured using replicate samples maintained in distilled water in a laboratory setting as well as in filtered water from four natural water bodies maintained in steel perforated drums (hereafter, mesocosms) within the field from autumn 2020 to spring 2021. There was limited evidence for the extended persistence of IAVs held in mesocosms; from 65 initial IAV-positive samples, only six IAVs persisted to at least 202 days in the mesocosms compared to 17 viruses persisting at least this long when held under temperature-controlled laboratory settings in distilled water. When accounting for the initial titer of samples, viruses detected at a higher concentration at the initiation of the experiment persisted longer than those with a lower starting titer. A parallel experimental laboratory model was used to further explore the effects of water type on viral persistence, and the results supported the finding of reduced tenacity of IAVs held in mesocosms compared to distilled water. The results of this investigation provide evidence that many factors, including temperature and physicochemical properties, impact the duration of viral infectivity in natural settings, further extending our understanding of the potential and limitations of environmental-based methodologies to recover infectious IAVs.

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USGS2024

Prion forensics: A multidisciplinary approach to investigate CWD at an illegal deer carcass disposal site

Infectious prions are resistant to degradation and remain infectious in the environment for several years. Chronic wasting disease (CWD) has been detected in cervids inhabiting North America, the Nordic countries, and South Korea. CWD-prion spread is partially attributed to carcass transport and disposal. We employed a forensic approach to investigate an illegal carcass dump site connected with a CWD-positive herd. We integrated anatomic, genetic, and prion amplification methods to discover CWD-positive remains from six white-tailed deer ( Odocoileus virginianus ) and, using microsatellite markers, confirmed a portion originated from the CWD-infected herd. This approach provides a foundation for future studies of carcass prion transmission risk.

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USGS2024

Effects of insecticide spray drift on arthropod prey resources of birds in grasslands in Minnesota

Soybean aphid ( Aphis glycines ) insecticides are used throughout the Upper Midwest and Great Plains regions of North America, including the farmland region of Minnesota, USA, to combat insect pests. These broad-spectrum, foliar spray insecticides have the potential to drift beyond target fields into nearby grassland cover where birds and other insectivores forage. Arthropods serve important roles in grassland ecology and are susceptible to mortality and sublethal effects from exposure to these pesticides. Our objective was to assess effects of soybean aphid insecticides on grassland arthropods, especially those that are important in grassland bird diets. We measured the abundance, consumable biomass, and family richness of insects and spiders in grasslands adjacent to soybean fields in an agricultural landscape. Soybean fields were treated with chlorpyrifos and lambda-cyhalothrin, which were the 2 most common foliar pesticides used to control soybean aphids in Minnesota. We compared measures at focal sites to samples collected at reference sites adjacent to corn fields not sprayed for aphids during 3 periods in mid-to-late summer: 1–3 days before spraying, 3–5 days post-spraying, and 19–21 days post-spraying. The abundance of arthropods in focal grasslands was lower 3–5 days after pesticide applications. Coleoptera family richness at focal sites was also lower than at reference sites 3–5 days after pesticide applications. These measures 19–21 days after application were similar to pre-spraying levels, indicating that arthropod populations rebounded during this period. Measures of consumable dry biomass, bird prey abundance, bird prey biomass, family richness of Araneae, family richness of Hemiptera, and family richness of Orthoptera were not different between focal and reference sites after spraying. Our results reveal that reductions in arthropod food abundance for grassland birds are associated with pesticide applications up to 5 days after spraying. We suggest that natural resource managers factor proximity to row crop fields and susceptibility to pesticide drift into decisions about where to add grassland cover to landscapes.

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USGS2024

Bird-habitat associations and local-scale vegetation structure in lowland brushlands

Brushlands support a diverse suite of bird species, including species of conservation concern in the western Great Lakes region of central North America. Information on how to effectively manage lowland brushlands for birds and associations between breeding birds and local-scale vegetation structure and composition is lacking. We surveyed lowland brushlands from 2016–2018 in Minnesota, USA, to assess bird-habitat associations using avian point-count surveys and fixed-radius vegetation plots. We used Poisson regression models to assess the associations between breeding bird species richness, total abundance, and abundance of frequently detected species (using counts as an index for abundance) to woody stem density and height, patchiness of woody stem density, variation of woody stem height, and number of woody plant species. Sedge wrens ( Cistothorus stellaris ), the most abundant species, were negatively associated with multiple woody plant metrics and positively associated with patchiness. Common yellowthroats ( Geothlypis trichas ) were the second-most abundant species and associated with low-stature woody plants (<1 m based on average heights in study sites). Bird species richness, alder flycatchers ( Empidonax alnorum ), chestnut-sided warblers ( Setophaga pensylvanica ), swamp sparrows ( Melospiza georgiana ), veeries ( Catharus fuscescens ), and yellow warblers ( Setophaga petechia ) increased with woody vegetation height. Chestnut-sided warbler and Nashville warbler ( Leiothlypis ruficapilla ) abundances also increased with woody stem density. We suggest that managing lowland brushlands to promote diverse woody plant structure, including tall shrubs and areas with patchy, open herbaceous cover, by implementing temporally and spatially variable disturbance regimes, may benefit bird species that rely on lowland brushlands with a range of vegetation structure requirements.

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