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USGS2023

Stream restoration milestones: Monitoring scales determine successes and failures

Urban stream restoration is growing globally, but there is much to learn from successes, failures, and evaluating tradeoffs in restoration practices. Significant time and resources have been invested towards restoring the structure and function of urban ecosystems and understanding and slowing the drivers of degradation. However, the rapid pace of urbanization and its effects on urban waters present an ever-growing challenge to environmental managers and restoration practitioners when identifying and prioritizing effective strategies for restoration and monitoring outcomes. Here, we synthesize major findings and papers originating from the 5th Symposium on Urbanization and Stream Ecology (SUSE5) and propose a new concept for monitoring restoration based on lessons learned. Efforts from SUSE5 showed that urban disturbances and restoration activities have strong localized impacts that can be challenging to detect and disentangle across broader watershed scales and longitudinal flowpaths. Most urban stream restoration projects are monitored at only one or a few locations that do not capture significant variability across stream reaches and longer flowpaths. Based on knowledge from SUSE5, we present a new concept called ‘restoration milestones.’ The restoration milestones concept proposes that the scale of stream monitoring over space and time can influence whether a stream restoration project is considered a success or failure. Therefore, answers to questions regarding restoration effectiveness and durability can be affected by spatial and temporal monitoring scales. Setting realistic restoration milestones involves establishing monitoring strategies that account for spatial and temporal variability. Tracking restoration performance through time across stream reaches along longitudinal flowpaths could aid in more accurately assessing project performance. We explore applications for evaluating restoration milestones along longitudinal stream flowpaths including: (1) identifying target areas of improvement along drainage networks, (2) accurately accounting for tradeoffs in habitat, protection of infrastructure, and water quality along flowpaths, and (3) detecting how far downstream the effects of stream restoration and stormwater management can be propagated. Monitoring across different spatial and temporal scales is an overlooked but critical factor in determining restoration success. Additionally, the scale of the restoration project itself can determine the type and magnitude of improvements. Expectations for what a restoration project can accomplish in terms of water quality improvements should be calibrated to the project’s spatial scale and evolution over time. Longitudinal studies of stream restoration help identify successes and failures along flowpaths.

Urban Ecosystems↗

USGS2016

A long-term study of ecological impacts of river channelization on the population of an endangered fish: Lessons learned for assessment and restoration

Projects to assess environmental impact or restoration success in rivers focus on project-specific questions but can also provide valuable insights for future projects. Both restoration actions and impact assessments can become “adaptive” by using the knowledge gained from long-term monitoring and analysis to revise the actions, monitoring, conceptual model, or interpretation of findings so that subsequent actions or assessments are better informed. Assessments of impact or restoration success are especially challenging when the indicators of interest are imperiled species and/or the impacts being addressed are complex. From 1997 to 2015, we worked closely with two federal agencies to monitor habitat availability for and population density of Roanoke logperch ( Percina rex ), an endangered fish, in a 24-km-long segment of the upper Roanoke River, VA. We primarily used a Before-After-Control-Impact analytical framework to assess potential impacts of a river channelization project on the P. rex population. In this paper, we summarize how our extensive monitoring facilitated the evolution of our (a) conceptual understanding of the ecosystem and fish population dynamics; (b) choices of ecological indicators and analytical tools; and (c) conclusions regarding the magnitude, mechanisms, and significance of observed impacts. Our experience with this case study taught us important lessons about how to adaptively develop and conduct a monitoring program, which we believe are broadly applicable to assessments of environmental impact and restoration success in other rivers. In particular, we learned that (a) pre-treatment planning can enhance monitoring effectiveness, help avoid unforeseen pitfalls, and lead to more robust conclusions; (b) developing adaptable conceptual and analytical models early was crucial to organizing our knowledge, guiding our study design, and analyzing our data; (c) catchment-wide processes that we did not monitor, or initially consider, had profound implications for interpreting our findings; and (d) using multiple analytical frameworks, with varying assumptions, led to clearer interpretation of findings than the use of a single framework alone. Broader integration of these guiding principles into monitoring studies, though potentially challenging, could lead to more scientifically defensible assessments of project effects.

Water↗

USGS2025

Wet meadow regeneration through restoration of biophysical feedbacks

Wet meadows are globally significant ecosystems that provide critical hydrological, ecological, and biogeochemical functions, yet their extent has declined dramatically due to land use changes and hydrologic alteration. These sedge-dominated wetlands exist at the drier end of the wetland gradient, maintained by shallow groundwater and periodic inundation. This paper is a global synthesis of the ecological, geomorphic, and hydrological dynamics of wet meadows, with an emphasis on alluvial systems, to inform effective restoration strategies. We compare wet meadows to other wetlands, classify them into palustrine, lacustrine, and alluvial types, then focus on alluvial wet meadows and discuss how their formation and persistence depend on ground and surface water interactions, sediment deposition and flow obstructions, all mediated by biological processes. In particular, we highlight the role of hydric graminoids in resisting erosion and maintaining soil cohesion, how beaver promote meadow persistence, and the significance of wet meadows as carbon sinks. We also present stratigraphic evidence demonstrating that incision, often triggered by anthropogenic activity or changing climate, is the primary mechanism of alluvial wet meadow degradation, resulting in water table decline and shifts in vegetation composition. Restoration requires reversing these incisional processes through techniques that elevate water tables, disperse flow and retain sediment—methods traditionally associated with either soil conservation or stream restoration. These include nature-based solutions that create obstructions such as beaver dams and their analogues, rock and wood-based obstructions and incision trench or gully filling and grading. Given their multifunctional value—including but not limited to flood attenuation, biodiversity support, and carbon sequestration—wet meadows warrant a focused restoration framework. This review advocates for a valley-floor scale restoration paradigm that integrates hydrological reconnection, sediment retention, and biological reinforcement to ensure long-term resilience of these systems in the face of changing climate and land use pressures.

Frontiers in Environmental Science↗

USGS2019

Influence of salinity on relative density of American crocodiles (Crocodylus acutus) in Everglades National Park: Implications for restoration of Everglades ecosystems

The status of the American crocodile (Crocodylus acutus) has long been a matter of concern in Everglades National Park (ENP) due to its classification as a federal and state listed species, its recognition as a flagship species, and its function as an ecosystem indicator. Survival and recovery of American crocodiles has been linked with regional hydrological conditions, especially freshwater flow to estuaries, which affect water levels and salinities. We hypothesize that efforts to restore natural function to Everglades ecosystems by improving water delivery into estuaries within ENP will change salinities and water levels which in turn will affect relative density of crocodiles. Monitoring ecological responses of indicator species, such as crocodiles, with respect to hydrologic change is necessary to evaluate ecosystem responses to restoration projects. Our objectives were to monitor trends in crocodile relative density within ENP and to determine influences of salinity on relative density of crocodiles. We examined count data from 12 years of crocodile spotlight surveys in ENP (2004 to 2015) and used a hierarchical model of relative density that estimated relative density with probability of detection. The mean predicted value for relative density (λ) across all surveys was 2.9 individuals/km (95% CI: 2.0 – 4.2); relative density was estimated to decrease with increases in salinity. Routes in ENP’s Flamingo/Cape Sable area had greater crocodile relative density than routes in the West Lake/Cuthbert Lake area and Northeast Florida Bay areas. These results are consistent with the hypothesis that restored flow and lower salinities will result in an increase in crocodile population size and provide support for the ecosystem management recommendations for crocodiles, which currently are to restore more natural patterns of freshwater flow to Florida Bay. Thus, monitoring relative density of American crocodiles will continue to be an effective indicator of ecological response to ecosystem restoration.

Florida↗

USGS2025

How high? Identifying elevation thresholds to guide coastal marsh restoration

Introduction Coastal marshes are highly valuable ecosystems facing threats from rising sea levels and intensifying storm events. To elevate marsh surfaces and prevent loss of ecosystem services, the beneficial use of dredged material (BUDM) is increasingly being implemented across the United States. Objectives The objective of this study was to aid decision-makers and restoration practitioners by identifying elevation thresholds that control the optimal function of Spartina patens -dominated marshes along the Texas Coast. Methods This study was conducted in the coastal marshes of the J.D. Murphree Wildlife Management Area (Texas). We collected elevation and vegetation cover data along ecological transition zones in marshes nourished with BUDM to identify elevation thresholds that define zones of optimal plant survivorship and growth. Results We identified lower (−0.05 m mean high water, MHW) and upper (0.26 m MHW) elevation thresholds that defined transitions to open water and unvegetated bare ground, respectively. Elevation targets ( T ) and elevation target zones, which defined areas with the greatest vegetation cover, were determined for S. patens ( T : 0.11 m, target zone: −0.06 to 0.26 m MHW), S. alterniflora ( T : 0.00 m, target zone: −0.12 to 0.10 m MHW), and Distichlis spicata ( T : 0.17 m, target zone: 0.07–0.25 m MHW). Conclusions Our analyses provide species-specific elevation targets for coastal marsh restoration through BUDM, which can improve restoration outcomes for coastal wetlands.

Texas↗

USGS2025

Quantifying regional ecological dynamics using agency monitoring data, ecological site descriptions, and ecological site groups

Information about what ecological conditions are likely, causes or drivers of degradation, and potential management actions to restore degraded lands may support land conservation and restoration decisions. State-and-transition models (STMs) describe persistent plant and ecological conditions that are possible (the “state”) within a given abiotic setting and drivers or actions that can cause shifts between states (the “transitions”). These primarily conceptual models are widely used to inform resource and conservation decisions. Data-driven STMs have been developed for some lands, but not at regional or national scales. Here, we demonstrate a new repeatable workflow for developing data-driven STMs in the United States (US). The approach leverages predictive maps of Ecological Site Groups (ESGs), extensive field-based Federal monitoring databases, information from Ecological Site Description (ESD) STMs, soil erosion models, remotely sensed productivity, and other available spatial information (fire, land protection, and drought) to provide context and descriptions of the data-driven states, including likely drivers of transitions. Results of this workflow applied to one dryland ESG in the Upper Colorado River Basin in the southwestern US suggest that an Invaded state (16% of 1352 plots) and some occurrences of a Grassland state (30% of plots) are in a degraded or at-risk condition with reduced ecosystem services. The most common drivers of state transitions in the associated ESDs ( n = 26) are related to livestock grazing and fire. The Invaded state in the ESG has evidence of degraded habitat quality and accelerated run-off while the Grassland state occurrences show reduced richness, productivity, and elevated erosion risk by wind. Areas subject to wildfire and with lower protection status had greater probability of Invaded state occurrence, generally supporting drivers in ESDs. The workflow presented here can serve as a template for describing ecological dynamics at regional scales, and support prioritization of land for conservation and climate adaptation activities.

Rangeland Ecology & Management↗

USGS2022

Ten-year ecological responses to fuel treatments within semiarid Wyoming big sagebrush ecosystems

Sagebrush ecosystems of western North America are threatened by invasive annual grasses and wildfires that can remove fire-intolerant shrubs for decades. Fuel reduction treatments are used ostensibly to aid in fire suppression, conserve wildlife habitat, and restore historical fire regimes, but long-term ecological impacts of these treatments are not clear. In 2006, we initiated fuel reduction treatments (prescribed fire, mowing, and herbicide applications [tebuthiuron and imazapic]) in six Artemisia tridentata ssp. wyomingensis communities. We evaluated long-term effects of these fuel treatments on: (1) magnitude and longevity of fuel reduction; (2) Greater Sage-grouse habitat characteristics; and (3) ecological resilience and resistance to invasive annual grasses. Responses were analyzed using repeated-measures linear mixed models. Response variables included plant biomass, cover, density and height, distances between perennial plants, and exposed soil cover. Prescribed fire produced the greatest reduction in woody fuel over time. Mowing initially reduced woody biomass, which recovered by year 10. Tebuthiuron did not significantly reduce woody biomass compared to controls. All woody fuel treatments reduced sagebrush cover to below 15% (recommended minimum for Greater Sage-grouse habitat), but only prescribed fire reduced cover to below controls. Median mowed sagebrush height remained above the recommended 30 cm. Cheatgrass ( Bromus tectorum ) cover increased to above the recommended maximum of 10% across all treatments and controls. Ecological resilience to woody fuel treatments was lowest with fire and greatest with mowing. Low resilience over the 10 posttreatment years was identified by: (1) poor perennial plant recovery posttreatment with sustained reductions in cover and density of some perennial plant species; (2) sustained reductions in lichen and moss cover; and (3) increases in cheatgrass cover. Although 10 years is insufficient to conclusively describe final ecological responses to fuel treatments, mowing woody fuels has the greatest potential to reduce woody fuel, minimize shrub mortality and soil disturbance, maintain lichens and mosses, and minimize long-term negative impacts on Greater Sage-grouse habitat. However, maintaining ecological resilience and resistance to invasion may be threatened by increases in cheatgrass cover, which are occurring regionally.

Idaho, Nevada, Oregon, Utah, Washington↗

USGS2024

Incorporating climate change into restoration decisions: Perspectives from dam removal practitioners

Incorporating climate change into conservation and restoration decisions is increasingly important for natural resource managers and restoration practitioners to effectively address the underlying drivers of ecosystem change. Small dam removal is an example of a restoration tool that may offer multiple socioeconomic and ecological benefits in streams, including promoting climate resilience. With the pace of dam removals increasing, practitioners and researchers are well-poised to incorporate climate change into future dam removal decisions. Therefore, we surveyed dam removal practitioners across 14 states in the eastern United States to understand current practices of small dam removals, factors driving restoration decisions, and how climate change knowledge is incorporated into these decisions. We also aimed to identify barriers to and opportunities for knowledge exchange between practitioners and researchers. Of the 100 respondents, most (79%) consider climate change in their dam removal decisions to some extent. Despite this, many reported a lack of clear, relevant, and accessible data linking small dam removal to climate resilience benefits. Dam removal practitioners also indicated that they most often rely on climate change information garnered from conversations with colleagues, rather than from scientific research products. These results suggest that the co-production of relevant, salient research questions and readily accessible and interpretable research products (e.g., technical summaries, open access articles) may encourage practitioners to incorporate climate change science more consistently and efficiently into dam removal decisions. These findings may also translate to other stream restoration efforts to inform knowledge exchange and improve restoration outcomes in a changing climate.

Connecticut, Delaware, Kentucky, Maine, Maryland, ↗

USGS2016

Endangered species management and ecosystem restoration: Finding the common ground

Management actions to protect endangered species and conserve ecosystem function may not always be in precise alignment. Efforts to recover the California Ridgway’s Rail ( Rallus obsoletus obsoletus ; hereafter, California rail), a federally and state-listed species, and restoration of tidal marsh ecosystems in the San Francisco Bay estuary provide a prime example of habitat restoration that has conflicted with species conservation. On the brink of extinction from habitat loss and degradation, and non-native predators in the 1990s, California rail populations responded positively to introduction of a non-native plant, Atlantic cordgrass ( Spartina alterniflora ). California rail populations were in substantial decline when the non-native Spartina was initially introduced as part of efforts to recover tidal marshes. Subsequent hybridization with the native Pacific cordgrass ( Spartina foliosa ) boosted California rail populations by providing greater cover and increased habitat area. The hybrid cordgrass ( S. alterniflora × S. foliosa ) readily invaded tidal mudflats and channels, and both crowded out native tidal marsh plants and increased sediment accretion in the marsh plain. This resulted in modification of tidal marsh geomorphology, hydrology, productivity, and species composition. Our results show that denser California rail populations occur in invasive Spartina than in native Spartina in San Francisco Bay. Herbicide treatment between 2005 and 2012 removed invasive Spartina from open intertidal mud and preserved foraging habitat for shorebirds. However, removal of invasive Spartina caused substantial decreases in California rail populations. Unknown facets of California rail ecology, undesirable interim stages of tidal marsh restoration, and competing management objectives among stakeholders resulted in management planning for endangered species or ecosystem restoration that favored one goal over the other. We have examined this perceived conflict and propose strategies for moderating harmful effects of restoration while meeting the needs of both endangered species and the imperiled native marsh ecosystem.

California↗

USGS2005

Implications of global climatic change and energy cost and availability for the restoration of the Mississippi delta

Over the past several thousand years, inputs from the Mississippi River formed the Mississippi delta, an area of about 25,000 km 2 . Over the past century, however, there has been a high loss of coastal wetlands of about 4800 km 2 . The main causes of this loss are the near complete isolation of the river from the delta, mostly due to the construction of flood control levees, and pervasive hydrological disruption of the deltaic plain. There is presently a large-scale State-Federal program to restore the delta that includes construction of water control structures in the flood control levees to divert river water into deteriorating wetlands and pumping of dredged sediment, often for long distances, for marsh creation. Global climate change and decreasing availability and increasing cost of energy are likely to have important implications for delta restoration. Coastal restoration efforts will have to be more intensive to offset the impacts of climate change including accelerated sea level rise and changes in precipitation patterns. Future coastal restoration efforts should also focus on less energy-intensive, ecologically engineered management techniques that use the energies of nature as much as possible. Diversions may be as important for controlling salinity as for providing sediments and nutrients for restoring coastal wetlands. Energy-intensive pumping-dredged sediments for coastal restoration will likely become much more expensive in the future.

Louisiana↗

USGS2008

Application of a geomorphic and temporal perspective to wetland management in North America

The failure of managed wetlands to provide a broad suite of ecosystem services (e.g., carbon storage, wildlife habitat, ground-water recharge, storm-water retention) valuable to society is primarily the result of a lack of consideration of ecosystem processes that maintain productive wetland ecosystems or physical and social forces that restrict a manager's ability to apply actions that allow those processes to occur. Therefore, we outline a course of action that considers restoration of ecosystem processes in those systems where off-site land use or physical alterations restrict local management. Upon considering a wetland system, or examining a particular management regime, there are several factors that will allow successful restoration of wetland services. An initial step is examination of the political/social factors that have structured the current ecological condition and whether those realities can be addressed. Most successful restorations of wetland ecosystem services involve cooperation among multiple agencies, acquisition of funds from non-traditional sources, seeking of scientific advice on ecosystem processes, and cultivation of good working relationships among biologists, managers, and maintenance staff. Beyond that, in on-site wetland situations, management should examine the existing hydrogeomorphic situation and processes (e.g., climatic variation, tides, riverine flood-pulse events) responsible for maintenance of ecosystem services within a given temporal framework appropriate for that wetland's hydrologic pattern. We discuss these processes for five major wetland types (depressional, lacustrine, estuarine, riverine, and man-made impoundments) and then provide two case histories in which this approach was applied: Seney National Wildlife Refuge with a restored fen system and Bosque del Apache National Wildlife Refuge where riverine processes have been simulated to restore native habitat. With adequate partnerships and administrative and political support, managers faced with degraded and/or disconnected wetland processes will be able to restore ecosystem services for society in our highly altered landscape by considering wetlands in their given hydrogeomorphic setting and temporal stage. ?? 2008 The Society of Wetland Scientists.

Wetlands↗

USGS2023

Trends, impacts, and cost of catastrophic and frequent wildfires in the sagebrush biome

Fire regimes in sagebrush ( Artemisia spp.) ecosystems have been greatly altered across the western United States. Broad-scale invasion of non-native annual grasses, climate change, and human activities have accelerated wildfire cycles, increased fire size and severity, and lengthened fire seasons in many sagebrush ecosystems to the point that current wildfire-management practices and postfire restoration efforts cannot keep pace to ameliorate the ecological consequences of sagebrush ecosystem loss. The greatest impact of uncharacteristically frequent fire is the transition from native sagebrush-perennial grass communities to invasive, non-native, annual grasslands that are highly flammable. These community transitions are often permanent, owing to the low probability of reestablishing native perennial plants in non-native annual grass−dominated communities. Moreover, these grasses can form extensive and continuous fine fuel loads that promote more frequent fire and the continued expansion of invasive, non-native annuals. More frequent, larger, and severe wildfires necessitate greater resources for fire-prevention, fire-suppression, and postfire restoration activities, while decreasing critical ecosystem services, economic and recreational opportunities, and cultural traditions. Increased flexibility and better prioritization of management activities based on ecological needs, including commitment to long-term prefire and postfire management, are needed to achieve notable reductions in uncharacteristic wildfire activity and associated negative impacts. Collaboration and partnerships across jurisdictional boundaries, agencies, and disciplines can improve consistency in sagebrush-management approaches and thereby contribute to this effort. Here, we provide a synthesis on sagebrush wildfire trends and the impacts of uncharacteristic fire regimes on sagebrush plant communities, dependent wildlife species, fire-suppression costs, and ecosystem services. We also provide an overview of wildland fire coordination efforts among federal, state, and tribal entities.

Rangeland Ecology and Management↗

USGS2013

Response of palila and other subalpine Hawaiian forest bird species to prolonged drought and habitat degradation by feral ungulates

Extinction has claimed half of all historically-known Hawaiian passerines, and today many extant species are increasingly threatened due to the combined effects of invasive species and climate change. Habitat disturbance has affected populations of feeding specialists most profoundly, and our results indicate that specialists continue to be most vulnerable, although even some abundant, introduced, generalist species also may be affected. Surveys of passerines during 1998–2011 in subalpine woodland habitat on Mauna Kea Volcano, Island of Hawai′i, revealed that the abundance of the critically endangered palila ( Loxioides bailleui ), a seed specialist, declined by 79% after 2003. The ′akiapōlā′au ( Hemignathus munroi ), an endangered specialist insectivore, was not detected in the survey area after 1998. The Hawai′i ′amakihi ( Hemignathus virens virens ), a generalist feeder and the most abundant species on Mauna Kea, was the only native species to maintain a stable population. The Japanese white-eye ( Zosterops japonicus ), a well-entrenched generalist and one of the three most common introduced species, declined. Drought prevailed in 74% of months during 2000–2011, and dry conditions contributed to the recent decline of the palila by reducing the annual māmane ( Sophora chrysophylla ) seed pod crop, which influences palila breeding and survival. Sustained browsing by introduced ungulates also lowered habitat carrying capacity, and their elimination should reduce the effects of drought and promote forest restoration. Our results illustrate how the feeding ecology of a species can influence its response to interacting environmental perturbations, and they underscore the value of long-term monitoring to detect population trends of sensitive species.

Hawai'i↗

USGS2002

The impact of buffer strips and stream-side grazing on small mammals in southwestern Wisconsin

The practice of continuously grazing cattle along streams has caused extensive degradation of riparian habitats. Buffer strips and managed intensive rotational grazing (MIRG) have been proposed to protect and restore stream ecosystems in Wisconsin. However, the ecological implications of a switch from traditional livestock management to MIRG or buffer strip establishment have not been investigated. Differences in small mammal communities associated with riparian areas on continuously grazed and MIRG pastures, as well as vegetative buffer strips adjacent to row crops, were investigated in southwestern Wisconsin during May-September 1997 and 1998. More species (mean of 6-7) were found on the buffer sites than on the pasture sites (mean of 2-5). Total small mammal abundance on buffer sites was greater than on the pastures as well: there were 3-5 times as many animals on the buffer sites compared to the pasture sites, depending on year. There were no differences in species richness or total abundance between MIRG and continuously grazed pastures in either year. Total small mammal abundance was greater near the stream than away from the stream, regardless of farm management practice but there were no differences in species richness. Buffer strips appear to support a particularly rich and abundant small mammal community. Although results did not detect a difference in small mammal use between pasture types, farm-wide implications of a conversion from continuous to MIRG styles of grazing may benefit small mammals indirectly by causing an increase in the prevalence of pasture in the agricultural landscape.

Agriculture, Ecosystems and Environment↗

USGS2005

Speciation of mercury and mode of transport from placer gold mine tailings

Historic placer gold mining in the Clear Creek tributary to the Sacramento River (Redding, CA) has highly impacted the hydrology and ecology of an important salmonid spawning stream. Restoration of the watershed utilized dredge tailings contaminated with mercury (Hg) introduced during gold mining, posing the possibility of persistent Hg release to the surrounding environment, including the San Francisco Bay Delta. Column experiments have been performed to evaluate the extent of Hg transport under chemical conditions potentially similar to those in river restoration projects utilizing dredge tailings such as at Clear Creek. Physicochemical perturbations, in the form of shifts in column influent ionic strength and the presence of a low molecular weight organic acid, were applied to coarse and fine sand placer tailings containing 109-194 and 69-90 ng of Hg/g, respectively. Significant concentrations of mercury, up to 16 ??g/L, leach from these sediments in dissolved and particle-associated forms. Sequential chemical extractions (SCE) of these tailings indicate that elemental Hg initially introduced during gold mining has been transformed to readily soluble species, such as mercury oxides and chlorides (3-4%), intermediately extractable phases that likely include (in)organic sorption complexes and amalgams (75-87%), and fractions of highly insoluble forms such as mercury sulfides (6-20%; e.g., cinnabar and metacinnabar). Extended X-ray absorption fine structure (EXAFS) spectroscopic analysis of colloids obtained from column effluent identified cinnabar particles as the dominant mobile mercury-bearing phase. The fraction of intermediately extractable Hg phases also likely includes mobile colloids to which Hg is adsorbed. ?? 2005 American Chemical Society.

Environmental Science & Technology↗

USGS2019

The ecology of chronic wasting disease in wildlife

Prions are misfolded infectious proteins responsible for a group of fatal neurodegenerative diseases termed transmissible spongiform encephalopathy or prion diseases. Chronic Wasting Disease (CWD) is the prion disease with the highest spillover potential, affecting at least seven Cervidae (deer) species. The zoonotic potential of CWD is inconclusive and cannot be ruled out. A risk of infection for other domestic and wildlife species is also plausible. Here, we review the current status of the knowledge with respect to CWD ecology in wildlife. Our current understanding of the geographic distribution of CWD lacks spatial and temporal detail, does not consider the biogeography of infectious diseases, and is largely biased by sampling based on hunters' cooperation and funding available for each region. Limitations of the methods used for data collection suggest that the extent and prevalence of CWD in wildlife is underestimated. If the zoonotic potential of CWD is confirmed in the short term, as suggested by recent results obtained in experimental animal models, there will be limited accurate epidemiological data to inform public health. Research gaps in CWD prion ecology include the need to identify specific biological characteristics of potential CWD reservoir species that better explain susceptibility to spillover, landscape and climate configurations that are suitable for CWD transmission, and the magnitude of sampling bias in our current understanding of CWD distribution and risk. Addressing these research gaps will help anticipate novel areas and species where CWD spillover is expected, which will inform control strategies. From an ecological perspective, control strategies could include assessing restoration of natural predators of CWD reservoirs, ultrasensitive CWD detection in biotic and abiotic reservoirs, and deer density and landscape modification to reduce CWD spread and prevalence.

Biological Reviews↗

USGS2007

Temporal changes of populations and trophic relationships of wintering diving ducks in Chesapeake Bay

Population and trophic relationships among diving ducks in Chesapeake Bay are diverse and complex as they include five species of bay ducks (Aythya spp.), nine species of seaducks (Tribe Mergini), and the Ruddy Duck (Oxyura jamaicensis). Here we considered the relationships between population changes and diet over the past half century to assess the importance of prey changes to wintering waterfowl in the Bay. Food habits of 643 diving ducks collected from Chesapeake Bay during 1999-2006 were determined by analyses of their gullet (esophagus and proventriculus) and gizzard contents and compared to historical data (1885-1979) of 1,541 diving ducks. Aerial waterfowl surveys, in general, suggest that six species of seaducks were more commonly located in the meso- to polyhaline areas of the Bay, whereas five species of bay ducks and Ruddy Ducks were in the oligo- to mesohaline areas. Seaducks fed on a molluscan diet of Hooked Mussel (Ischadium recurvum), Amethyst Gemclam (Gemma gemma), and Dwarf Surfclarn (Mulinia lateralis). Bay ducks and Ruddy Ducks fed more on Baltic Macoma (Macoma balthica), the adventive Atlantic Rangia (Rangia cuneata), and submerged aquatic vegetation (SAV). Mergansers were found over the widest salinity range in the Bay, probably because of their piscivorous diet. Each diving duck species appears to fill a unique foraging niche, although there is much overlap of selected prey. When current food habits are compared to historic data, only the Canvasback (Aythya valisineria) has had major diet changes, although SAV now accounts for less food volume for all diving duck species, except the Redhead (Aythya americana). Understanding the trophic-habitat relationships of diving ducks in coastal wintering areas will give managers a better understanding of the ecological effects of future environmental changes. Intensive restoration efforts on SAV and oyster beds should greatly benefit diving duck populations.

Waterbirds↗

USGS2019

Wildland fire science at the U.S. Geological Survey—Supporting wildland fire and land management across the United States postcard

The U.S. Geological Survey’s Wildland Fire Science Program produces information to identify the causes of wildfires, understand the impacts and benefits of both wildfires and prescribed fires, and help prevent and manage larger, catastrophic events. USGS fire scientists provide information and develop tools that are widely used by stakeholders to make decisions before, during, and after wildfires in desert, grassland, tundra, wetland, and forest ecosystems across the United States. Active areas of research include— Wildland fire behavior and risk management Fire ecology, fire effects, and post-fire restoration of ecosystems Risk assessments for human health, public safety, and the Nation’s infrastructure Remote sensing and geospatial tools and data.

General Information Product↗