SEARCH · Geology Reports

Results for “Ecological Engineering”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources

USGS2009

Geomorphic segmentation, hydraulic geometry, and hydraulic microhabitats of the Niobrara River, Nebraska — Methods and initial results

The Niobrara River of Nebraska is a geologically, ecologically, and economically significant resource. The State of Nebraska has recognized the need to better manage the surface- and ground-water resources of the Niobrara River so they are sustainable in the long term. In cooperation with the Nebraska Game and Parks Commission, the U.S. Geological Survey is investigating the hydrogeomorphic settings and hydraulic geometry of the Niobrara River to assist in characterizing the types of broad-scale physical habitat attributes that may be of importance to the ecological resources of the river system. This report includes an inventory of surface-water and ground-water hydrology data, surface water-quality data, a longitudinal geomorphic segmentation and characterization of the main channel and its valley, and hydraulic geometry relations for the 330-mile section of the Niobrara River from Dunlap Diversion Dam in western Nebraska to the Missouri River confluence. Hydraulic microhabitats also were analyzed using available data from discharge measurements to demonstrate the potential application of these data and analysis methods. The main channel of the Niobrara was partitioned into three distinct fluvial geomorphic provinces: an upper province characterized by open valleys and a sinuous, equiwidth channel; a central province characterized by mixed valley and channel settings, including several entrenched canyon reaches; and a lower province where the valley is wide, yet restricted, but the river also is wide and persistently braided. Within the three fluvial geomorphic provinces, 36 geomorphic segments were identified using a customized, process-orientated classification scheme, which described the basic physical characteristics of the Niobrara River and its valley. Analysis of the longitudinal slope characteristics indicated that the Niobrara River longitudinal profile may be largely bedrock-controlled, with slope inflections co-located at changes in bedrock type at river level. Hydraulic geometry relations indicated that local (at-a-station) channel adjustments of the Niobrara River to changing discharge are accommodated mainly by changes in velocity, and streamwise adjustments are accommodated through changes in channel width. Downstream hydraulic geometry relations are in general agreement with values previously published for rivers of the Great Plains, but coefficients are likely skewed low because the locations of the streamflow-gaging stations used in this analysis are located at natural or engineered constrictions and may not be accurately representing downstream adjustment processes of the Niobrara River. A demonstration analysis of hydraulic microhabitat attributes at a single station indicated that changes in velocity-related habitat types is the primary microhabitat adjustment over a range of discharges, but the magnitude of that adjustment for any particular discharge is temporally variable.

Nebraska↗

USGS2024

A heuristic method to evaluate consequences for flight control and stability induced by attachment of biologging devices to birds and bats

Biologging is central to the study of wildlife, but questions remain about the minimization of effects of biologging devices. Rarely considered are changes biologging devices induce on an animal's centre of mass (COM) and resulting losses of flight control and stability. We applied established aeronautical principles to estimate how the COM of a flying bird or bat may be affected by the typical positioning of a biologging device on the neck, back, hips or tail. We then adopted modified thresholds from aerospace engineering to estimate limits beyond which changes to COM result in fitness-relevant alterations to flight control and stability. Generic models illustrate a trade-off between the placement and mass of a biologging device that influences flight control and stability. Seven species-specific examples show the substantial differences in consequences of changes to COM for animals of different sizes and body types. Placement of a device on the tail always resulted in the greatest shift in COM and placement in the centre of the back resulted in the smallest shift. The 5% weight threshold some use for a biologging device provides little room for error in terms of stability and can easily cause dangerous changes to COM. The 3% weight threshold others use causes considerably smaller changes in the COM, but when placed away from the natural COM, still can affect flight control and stability. Researchers interested in minimizing the effects to fitness of wildlife should consider weight, balance and COM when affixing biologging devices. The farther a device is from the natural COM, the smaller it should be relative to the mass of the animal.

Methods in Ecology and Evolution↗

USGS2012

An environmental streamflow assessment for the Santiam River basin, Oregon

The Santiam River is a tributary of the Willamette River in northwestern Oregon and drains an area of 1,810 square miles. The U.S. Army Corps of Engineers (USACE) operates four dams in the basin, which are used primarily for flood control, hydropower production, recreation, and water-quality improvement. The Detroit and Big Cliff Dams were constructed in 1953 on the North Santiam River. The Green Peter and Foster Dams were completed in 1967 on the South Santiam River. The impacts of the structures have included a decrease in the frequency and magnitude of floods and an increase in low flows. For three North Santiam River reaches, the median of annual 1-day maximum streamflows decreased 42–50 percent because of regulated streamflow conditions. Likewise, for three reaches in the South Santiam River basin, the median of annual 1-day maximum streamflows decreased 39–52 percent because of regulation. In contrast to their effect on high flows, the dams increased low flows. The median of annual 7-day minimum flows in six of the seven study reaches increased under regulated streamflow conditions between 60 and 334 percent. On a seasonal basis, median monthly streamflows decreased from February to May and increased from September to January in all the reaches. However, the magnitude of these impacts usually decreased farther downstream from dams because of cumulative inflow from unregulated tributaries and groundwater entering the North, South, and main-stem Santiam Rivers below the dams. A Wilcox rank-sum test of monthly precipitation data from Salem, Oregon, and Waterloo, Oregon, found no significant difference between the pre-and post-dam periods, which suggests that the construction and operation of the dams since the 1950s and 1960s are a primary cause of alterations to the Santiam River basin streamflow regime. In addition to the streamflow analysis, this report provides a geomorphic characterization of the Santiam River basin and the associated conceptual framework for assessing possible geomorphic and ecological changes in response to river-flow modifications. Suggestions for future biomonitoring and investigations are also provided. This study was one in a series of similar tributary streamflow and geomorphic studies conducted for the Willamette Sustainable Rivers Project. The Sustainable Rivers Project is a national effort by the USACE and The Nature Conservancy to develop environmental flow requirements in regulated river systems.

Oregon↗

USGS2000

Louisiana coastal ecosystem

Louisiana's coast and its degradation and restoration are major environmental issues being studied at the National Wetlands Research Center. Coastal ecosystems are vulnerable because of the tremendous amount of human activity that takes place along the coast. Information on ecological processes is essential to guide the development along the coast as well as to protect and restore wildlife habitat. Louisiana has about 40% of coastal wetlands in the lower 48 states; they support fish, waterfowl, and fur-bearing animals as well as unique cultures like that of the Acadians. The fish and wildlife resources of Louisiana's coast produce over $1 billion each year in revenues. But Louisiana has the highest coastal loss rate because of natural and human causes. Over the past three decades, Louisiana has lost as much as 35-40 mi 2 (90-104 km 2 ) of coastal wetlands a year. The National Wetlands Research Center is qualified to assess and monitor this ecosystem because of its proximity to the study area, a staff chosen for their expertise in the system, and a number of established partnerships with others who study the areas. The Center is often the lead group in partnerships with universities, other federal agencies, and private entities who study this ecosystem. Most of the Center's research and technology development performed for coastal wetlands are done at the Lafayette headquarters; some work is performed at the National Wetlands Research Center's project office in Baton Rouge, LA.

Fact Sheet↗

USGS2011

Engineering a future for amphibians under climate change

1. Altered global climates in the 21st century pose serious threats for biological systems and practical actions are needed to mount a response for species at risk. 2. We identify management actions from across the world and from diverse disciplines that are applicable to minimizing loss of amphibian biodiversity under climate change. Actions were grouped under three thematic areas of intervention: (i) installation of microclimate and microhabitat refuges; (ii) enhancement and restoration of breeding sites; and (iii) manipulation of hydroperiod or water levels at breeding sites. 3. Synthesis and applications. There are currently few meaningful management actions that will tangibly impact the pervasive threat of climate change on amphibians. A host of potentially useful but poorly tested actions could be incorporated into local or regional management plans, programmes and activities for amphibians. Examples include: installation of irrigation sprayers to manipulate water potentials at breeding sites; retention or supplementation of natural and artificial shelters (e.g. logs, cover boards) to reduce desiccation and thermal stress; manipulation of canopy cover over ponds to reduce water temperature; and, creation of hydrologoically diverse wetland habitats capable of supporting larval development under variable rainfall regimes. We encourage researchers and managers to design, test and scale up new initiatives to respond to this emerging crisis.

Journal of Applied Ecology↗

USGS2007

Poplar Island Environmental Restoration Project: Challenges in waterbird restoration on an island in Chesapeake Bay

At 460 hectares, the Paul Sarbanes Environmental Restoration Project at Poplar Island, Talbot County, Maryland, represents the largest 'beneficial use' dredged material project of the U. S. Army Corps of Engineers (a cooperative project with Maryland Port Administration). Begun in 1998, the 15-year restoration project will ultimately consist of roughly 220 ha of uplands and 220 ha of tidal wetland habitats, with limited areas of dike roads, perimeter riprap, and unvegetated mudflats. Wetland restoration began in one small section (or 'cell') in 2002, but not all cells will be filled with dredged material until at least 2013. As a major objective of the restoration, six species of waterbirds were identified as 'priority species' for Chesapeake Bay: American black duck ( Anas rubripes ), snowy egret ( Egretta thula ), cattle egret ( Bubulcus ibis ), osprey ( Pandion haliaetus ), common tern ( Sterna hirundo ), and least tern ( S. antillarum ). Monitoring of nesting activities of these species from 2002 to 2005 indicated that all species except black ducks colonized the site rapidly. More than 800 pairs of common terns nested in 2003 to 2004. Because of predation by red fox ( Vulpes vulpes ) and great horned owl ( Bubo virginianus ), reproductive success was very low for the terns. Trapping was effective in removing the foxes, and other controls have been applied to opportunistic nesting species including herring gulls ( Larus argentatus ) and Canada geese ( Branta canadensis ). An effective public education program on the island has helped address concerns about animal control.

Maryland↗

USGS2026

Variation in diet and lipid content of age-0 sturgeon (Scaphirhynchus sp.) in the lower Missouri River basin

Shovelnose sturgeon ( Scaphirhynchus platorynchus ) and related endangered pallid sturgeon ( S. albus ) are species of interest in the highly modified Missouri River. Scaphirhynchus sturgeon require long distances of riverine habitat for the development of drifting free embryos along with suitable foraging habitat during the subsequent transition to exogenous feeding. Working with specimens collected by the US Army Corps of Engineers and Nebraska Game and Parks Commission, we examined diet composition of age-0 (<12 cm) sturgeon at four reaches in the lower Missouri River to examine the potential role of prey acquisition at this vulnerable life stage. In general, Ephemeroptera were more represented at reaches further upstream in the lower Missouri River, whereas Diptera larvae were the dominant prey item in reaches downstream. Body condition, as measured by total lipid content and length‒weight regressions, exhibited spatial differences in 2016 but not in 2017. Even with differences in prey frequencies and numbers consumed, percent consumption regardless of prey type remained consistent among reaches within years, but was overall higher in 2016 when river discharge was greater. Although temporal and spatial differences were observed in condition, comparisons using previous data from 2014 and 2015 suggest that these condition results were not driven by the longitudinal variability in prey composition as the reaches below Kansas city yielded relatively high and low lipid values despite the limited consumption of ephemeropteran prey relative to upstream reaches. Although it is unknown if any of the observed differences affected survival, our results, coupled with previous work, suggest that age-0 sturgeon can opportunistically forage in the lower Missouri River.

Missouri River↗

USGS2026

Single receiver target localization in mobile marine acoustic telemetry

Many marine ecological studies track animal movement and migration using acoustic telemetry, in which animals are implanted with acoustic transmitters broadcasting a unique ID code. Receivers detect and decode these transmissions and provide an estimate of the animal’s location. As transmissions can be detected at distances of hundreds of meters to even several kilometers, localization performed using binary detection information is very coarse. Fine-scale localization can be performed using time difference of arrival systems, but such systems are costlier and require a greater number of receivers. We present a Bayesian method for target localization using only binary detection information collected by a single receiver mounted on a mobile platform. The approach reduces error in the location estimate by considering the distance-dependent probability of detection (detection efficiency curve), which must first be characterized. Stationary receivers are used to infer failed detections. This localization method is then used to inform waypoint selection for the mobile platform, using the second nondominated sorting genetic algorithm considering the tradeoff between the travel distance of the platform and localization error. Simulation results examine the effects of detection efficiency curve characteristics, number of transmissions, and travel distance on the localization error. The proposed method is further supported by experimental results from field trials conducted with an autonomous surface vehicle in Lake Huron.

IEEE Journal of Oceanic Engineering↗

USGS2010

A Natural History Summary and Survey Protocol for the Southwestern Willow Flycatcher

The Southwestern Willow Flycatcher (Empidonax traillii extimus) has been the subject of substantial research, monitoring, and management activity since it was listed as an endangered species in 1995. When proposed for listing in 1993, relatively little was known about the flycatcher's natural history, and there were only 30 known breeding sites supporting an estimated 111 territories rangewide (Sogge and others, 2003a). Since that time, thousands of presence/absences surveys have been conducted throughout the historical range of the flycatcher, and many studies of its natural history and ecology have been completed. As a result, the ecology of the flycatcher is much better understood than it was just over a decade ago. In addition, we have learned that the current status of the flycatcher is better than originally thought: as of 2007, the population was estimated at approximately 1,300 territories distributed among approximately 280 breeding sites (Durst and others, 2008a). Concern about the Southwestern Willow Flycatcher on a rangewide scale was brought to focus by Unitt (1987), who described declines in flycatcher abundance and distribution throughout the Southwest. E. t. extimus populations declined during the 20th century, primarily because of habitat loss and modification from activities, such as dam construction and operation, groundwater pumping, water diversions, and flood control. In 1991, the U.S. Fish and Wildlife Service (USFWS) designated the Southwestern Willow Flycatcher as a candidate category 1 species (U.S. Fish and Wildlife Service, 1991). In July 1993, the USFWS proposed to list E. t. extimus as an endangered species and to designate critical habitat under the Act (U.S. Fish and Wildlife Service, 1993). A final rule listing E. t. extimus as endangered was published in February 1995 (U.S. Fish and Wildlife Service, 1995); critical habitat was designated in 1997 (U.S. Fish and Wildlife Service, 1997). The USFWS Service released a Recovery Plan for the Southwestern Willow Flycatcher in 2002 (U.S. Fish and Wildlife Service, 2002), and re-designated critical habitat in 2005 (U.S. Fish and Wildlife Service, 2005).

Techniques and Methods↗

USGS2022

Poplar Island: Understanding the development of a beneficial use restoration site

Poplar Island, like many other islands throughout the Chesapeake Bay, eroded from 460 hectares in 1847 to only 1.5 hectares by the 1990’s. However, the U.S. Army Corps of Engineers, Maryland Department of Transportation, and numerous other state and federal agencies selected this site as the location of a beneficial use project aimed at restoring remote island habitat in the Chesapeake Bay using clean dredge material. While monitoring efforts since the beginning of restoration efforts have documented extensive use of Poplar Island by numerous species across multiple taxa, these efforts have previously lacked context regarding underlying habitat patterns. However, such information is especially important on a site like Poplar Island where habitat distribution and availability can change dramatically between years due to ongoing construction efforts. To address this information gap we digitized annual aerial imagery of Poplar Island from 2006-2017 into 20 habitat classes. The resulting data layers demonstrate the transition of cells along the eastern side of the island from undeveloped cells to planted marsh cells, which matches trends seen in avian monitoring data. Similarly, our data display changes in the distribution of specific resources such as sand across the island, and how individual locations of interest such as constructed habitat islands have evolved over time. We believe that these data will provide critical insight into the factors influencing wildlife distribution patterns on Poplar Island, and will allow for the identification of management actions that may either be targeted or avoided in the planning of future beneficial use projects.

Maryland↗

USGS2012

Monitoring of endangered Roanoke logperch ( Percina rex ) in Smith River upstream from the Philpott Reservoir on U.S. Army Corps of Engineers property near Martinsville, Virginia

The purpose of this study was to continue annual monitoring of Roanoke logperch ( Percina rex ), an endangered fish, in the Smith River immediately upstream from Philpott Reservoir. This river reach is owned by the U.S. Army Corps of Engineers (USACE), which must ensure that appropriate actions are undertaken to aid in recovery of logperch. Monitoring of fish abundance and habitat conditions provides a means for assessing the species’ status and its responses to USACE management actions. The Roanoke logperch is a large darter (Percidae: Etheostomatinae) endemic to the Roanoke, Dan, and Nottoway River basins of Virginia and North Carolina, where it occupies third- to sixth-order streams containing relatively silt-free substrate (Jenkins and Burkhead, 1994). Because of its rarity, small range, and vulnerability to siltation, the Roanoke logperch was listed in 1989 as endangered under the U.S. Endangered Species Act (ESA) (U.S. Federal Register 54:34468-34472). Within the Dan basin, Roanoke logperch have long been known to occupy the Smith River and one of its largest tributaries, Town Creek (Jenkins and Burkhead, 1994). Logperch also recently were discovered in other tributaries of the Dan River, including North Carolina segments of the Mayo River, Cascade Creek, Big Beaver Island Creek, Wolf Island Creek (William Hester, U.S. Fish and Wildlife Service, personal commun., 2012). Within the Smith River, Roanoke logperch are present both upstream and downstream from Philpott Reservoir, a hydroelectric and water storage project owned and operated by the USACE. Although logperch have not been observed in the reservoir itself, the species is relatively abundant in a free-flowing, ≈ 2.5-km-long segment of Smith River upstream from the reservoir on USACE property (Lahey and Angermeier, 2006). This segment is bounded on the downstream end by the lentic conditions of the reservoir and on the upstream end by White Falls, a natural waterfall that presumably allows fish passage during all but the lowest streamflow (Roberts and Angermeier, 2009). The ESA stipulates that USACE must ensure that its actions do not jeopardize Roanoke logperch and ensure that appropriate actions are taken to aid in the recovery of Roanoke logperch. USACE recognized that additional information was needed to assess compliance with these stipulations, including data on baseline population levels, habitat availability, and potential threats to the species on USACE property. USACE therefore contracted with Virginia Tech (VT) and the U.S. Geological Survey via the Virginia Cooperative Fisheries and Wildlife Research Unit (VCFWRU) to continue ecological monitoring that was initiated in a pilot study in 2005 (Lahey and Angermeier, 2006). The VCFWRU is jointly sponsored by the U.S. Geological Survey, Virginia Tech, Virginia Department of Game and Inland Fisheries, and Wildlife Management Institute. This final report summarizes results of biological monitoring performed by VT and the VCFWRU in 2011, and compares these data to data collected during 2006–2010 (Roberts and Angermeier, 2011). Where appropriate, a comparison was made to data on Roanoke logperch collected previously in the study reach (Lahey and Angermeier, 2006) and in the upper Roanoke River (Roberts and Angermeier, 2011). This work was performed under the auspices of VT’s Institutional Animal Care and Use Committee (IACUC) protocol 11-035-FIW. Specifically, the following objectives were addressed: * Estimate population density of Roanoke logperch on USACE property; * Measure and map by suitability class the distribution of habitat suitable for Roanoke logperch in the project area; * Assess water quality relative to Roanoke logperch habitat in the project area; * Use the data on logperch abundance, habitat suitability, and water quality to test the general validity of correlates of logperch abundance from other locations; * Identify opportunities and threats related to protecting and enhancing Roanoke logperch habitat; and * Provide suggestions on the necessity and scale of future studies and monitoring related to logperch in and near USACE waters.

Virginia↗

USGS2017

Cobalt

Cobalt is a silvery gray metal that has diverse uses based on certain key properties, including ferromagnetism, hardness and wear-resistance when alloyed with other metals, low thermal and electrical conductivity, high melting point, multiple valences, and production of intense blue colors when combined with silica. Cobalt is used mostly in cathodes in rechargeable batteries and in superalloys for turbine engines in jet aircraft. Annual global cobalt consumption was approximately 75,000 metric tons in 2011; China, Japan, and the United States (in order of consumption amount) were the top three cobalt-consuming countries. In 2011, approximately 109,000 metric tons of recoverable cobalt was produced in ores, concentrates, and intermediate products from cobalt, copper, nickel, platinum-group-element (PGE), and zinc operations. The Democratic Republic of the Congo (Congo [Kinshasa]) was the principal source of mined cobalt globally (55 percent). The United States produced a negligible amount of byproduct cobalt as an intermediate product from a PGE mining and refining operation in southeastern Montana; no U.S. production was from mines in which cobalt was the principal commodity. China was the leading refiner of cobalt, and much of its production came from cobalt ores, concentrates, and partially refined materials imported from Congo (Kinshasa). The mineralogy of cobalt deposits is diverse and includes both primary (hypogene) and secondary (supergene) phases. Principal terrestrial (land-based) deposit types, which represent most of world’s cobalt mine production, include primary magmatic Ni-Cu(-Co-PGE) sulfides, primary and secondary stratiform sediment-hosted Cu-Co sulfides and oxides, and secondary Ni-Co laterites. Seven additional terrestrial deposit types are described in this chapter. The total terrestrial cobalt resource (reserves plus other resources) plus past production, where available, is calculated to be 25.5 million metric tons. Additional resources of cobalt are known to occur on the modern sea floor in aerially extensive deposits of Fe-Mn(-Ni-Cu-Co-Mo) nodules and Fe-Mn(-Co-Mo-rare-earth-element) crusts. Legal, economic, and technological barriers have prevented exploitation of these cobalt resources, which lie at water depths of as great as 6,000 meters, although advances in technology may soon allow production of these resources to be economically viable. Environmental issues related to cobalt mining concern mainly the elevated cobalt contents in soils and waters. Although at low levels cobalt is essential to human health (it is the central atom in the critical nutrient vitamin B12), overexposure to high levels of cobalt may cause lung and heart dysfunction, as well as dermatitis. The ecological impacts of cobalt vary widely and can be severe for some species of fish and plants, depending on various environmental factors.

Professional Paper↗

USGS2019

A spatial model of streaked horned lark breeding habitat in the Columbia River, USA

The streaked horned lark (hereafter “lark”; Eremophila alpestris strigata ) is a federally listed bird subspecies of the Pacific Northwest that occupies open landscapes with short vegetation and abundant bare ground. Across its breeding range, which has contracted dramatically, the lark relies primarily on human-modified habitats maintained in early successional states (e.g., agricultural fields, airfields, deposition islands). The focus of our study is the lower Columbia River where larks primarily occupy deposition islands created as a byproduct of shipping channel deepening (dredging) projects. The U.S. Army Corps of Engineers has proactively adopted a shifting-habitat-mosaic management approach when placing dredge (sand) materials to maintain lark habitat throughout the project area. To help achieve their goal, we created a geospatial tool capable of quantifying and tracking habitat suitability for larks throughout the project area with satellite imagery. We created spatial models of lark breeding habitat by incorporating lark survey data, Sentinel-2 satellite imagery, dredge-deposition maps, and surface-elevation models. We built candidate predictive models of lark breeding habitat after combining survey data (years 2016 and 2017), predictor variables, and logistic regression. In addition, we created a novel seral-stage predictor variable to identify young, mature, old, and unsuitable locations; critical information for lark conservation planning and dredge-disposal operational planning. We challenged probability models the year they were constructed (2016) and the following year (2017) with set-aside survey data. The best model contained terrain ruggedness, deposition age, vegetation greenness (e.g., lushness and density of vegetation) inside a 10-m cell, and heterogeneity in greenness within a 100-m radius. Verification accuracy ranged from 75 to 83% depending on the model tested and year. Importantly, the seral-stage variable allowed us to quantify and locate early, optimal, and late habitats. Model results will facilitate conservation planning decisions by informing real-time management decisions. Furthermore, they provide a foundation for application in other human-modified habitats across the species’ range.

Oregon↗

USGS2025

Developing biocrust field cultivation techniques for soil restoration: An assessment of bacterial communities

Biological soil crusts (biocrusts) are a coherent, thin soil surface layer, engineered and inhabited by a diverse community of moss, lichen, cyanobacteria, and other microorganisms. Biocrusts provide critical functions in dryland systems and may be lost from the ecosystem through physical disturbance or other global change drivers. Once biocrusts are lost, natural recovery can occur very slowly. This has led to the development of biocrust rehabilitation strategies, including cultivation of biocrust propagules to inoculate degraded sites. As the need for biocrust restoration grows in scale and across different regions, inoculum cultivation and application methods are being asked to keep up. In this work, we evaluate cyanobacterial community composition and abundance in greenhouse and field cultivation systems, with and without growth substrate and shade treatments. We also consider cultivation of locally and non-locally sourced biocrust inocula at a single cultivation facility on the Colorado Plateau. We found that field cultivation is a viable option for biocrust cultivation. For almost all cyanobacteria, habitat amelioration was necessary for growth in the field. Despite differences in inocula composition following cultivation, restoration outcomes five months after inoculation were poor with no significant increases in cyanobacterial abundance, soil chlorophyll a , or soil exopolysaccharide content. Thus, more work is needed to boost the initial growth and survival of biocrust inocula, regardless of the method of cultivation (i.e., greenhouse or field). Future work focused on assessing opportunities for habitat amelioration during application to improve biocrust establishment during this critical restoration phase would be highly valuable.

Utah↗

USGS2022

Machine learned daily life history classification using low frequency tracking data and automated modelling pipelines: Application to North American waterfowl

Background Identifying animal behaviors, life history states, and movement patterns is a prerequisite for many animal behavior analyses and effective management of wildlife and habitats. Most approaches classify short-term movement patterns with high frequency location or accelerometry data. However, patterns reflecting life history across longer time scales can have greater relevance to species biology or management needs, especially when available in near real-time. Given limitations in collecting and using such data to accurately classify complex behaviors in the long-term, we used hourly GPS data from 5 waterfowl species to produce daily activity classifications with machine-learned models using “automated modelling pipelines”. Methods Automated pipelines are computer-generated code that complete many tasks including feature engineering, multi-framework model development, training, validation, and hyperparameter tuning to produce daily classifications from eight activity patterns reflecting waterfowl life history or movement states. We developed several input features for modeling grouped into three broad categories, hereafter “feature sets”: GPS locations, habitat information, and movement history. Each feature set used different data sources or data collected across different time intervals to develop the “features” (independent variables) used in models. Results Automated modelling pipelines rapidly developed easily reproducible data preprocessing and analysis steps, identification and optimization of the best performing model and provided outputs for interpreting feature importance. Unequal expression of life history states caused unbalanced classes, so we evaluated feature set importance using a weighted F1-score to balance model recall and precision among individual classes. Although the best model using the least restrictive feature set (only 24 hourly relocations in a day) produced effective classifications (weighted F1 = 0.887), models using all feature sets performed substantially better (weighted F1 = 0.95), particularly for rarer but demographically more impactful life history states (i.e., nesting). Conclusions Automated pipelines generated models producing highly accurate classifications of complex daily activity patterns using relatively low frequency GPS and incorporating more classes than previous GPS studies. Near real-time classification is possible which is ideal for time-sensitive needs such as identifying reproduction. Including habitat and longer sequences of spatial information produced more accurate classifications but incurred slight delays in processing.

Movement Ecology↗

USGS2013

Trajectory of the arctic as an integrated system

Although much remains to be learned about the Arctic and its component processes, many of the most urgent scientific, engineering, and social questions can only be approached through a broader system perspective. Here, we address interactions between components of the Arctic System and assess feedbacks and the extent to which feedbacks (1) are now underway in the Arctic; and (2) will shape the future trajectory of the Arctic system. We examine interdependent connections among atmospheric processes, oceanic processes, sea-ice dynamics, marine and terrestrial ecosystems, land surface stocks of carbon and water, glaciers and ice caps, and the Greenland ice sheet. Our emphasis on the interactions between components, both historical and anticipated, is targeted on the feedbacks, pathways, and processes that link these different components of the Arctic system. We present evidence that the physical components of the Arctic climate system are currently in extreme states, and that there is no indication that the system will deviate from this anomalous trajectory in the foreseeable future. The feedback for which the evidence of ongoing changes is most compelling is the surface albedo-temperature feedback, which is amplifying temperature changes over land (primarily in spring) and ocean (primarily in autumn-winter). Other feedbacks likely to emerge are those in which key processes include surface fluxes of trace gases, changes in the distribution of vegetation, changes in surface soil moisture, changes in atmospheric water vapor arising from higher temperatures and greater areas of open ocean, impacts of Arctic freshwater fluxes on the meridional overturning circulation of the ocean, and changes in Arctic clouds resulting from changes in water vapor content.

Ecological Applications↗

USGS2023

Approaching the upper boundary of driver-response relationships: Identifying factors using a novel framework integrating quantile regression with interpretable machine learning

The identification of factors that may be forcing ecological observations to approach the upper boundary provides insight into potential mechanisms affecting driver-response relationships, and can help inform ecosystem management, but has rarely been explored. In this study, we propose a novel framework integrating quantile regression with interpretable machine learning. In the first stage of the framework, we estimate the upper boundary of a driver-response relationship using quantile regression. Next, we calculate “potentials” of the response variable depending on the driver, which are defined as vertical distances from the estimated upper boundary of the relationship to observations in the driver-response variable scatter plot. Finally, we identify key factors impacting the potential using a machine learning model. We illustrate the necessary steps to implement the framework using the total phosphorus (TP)-Chlorophyll a (CHL) relationship in lakes across the continental US. We found that the nitrogen to phosphorus ratio (N:P), annual average precipitation, total nitrogen (TN), and summer average air temperature were key factors impacting the potential of CHL depending on TP. We further revealed important implications of our findings for lake eutrophication management. The important role of N:P and TN on the potential highlights the co-limitation of phosphorus and nitrogen and indicates the need for dual nutrient criteria. Future wetter and/or warmer climate scenarios can decrease the potential which may reduce the efficacy of lake eutrophication management. The novel framework advances the application of quantile regression to identify factors driving observations to approach the upper boundary of driver-response relationships.

Frontiers of Environmental Science & Engineering↗

USGS2000

Enrichment of Geobacter species in response to stimulation of Fe(III) reduction in sandy aquifer sediments

Engineered stimulation of Fe(III) has been proposed as a strategy to enhance the immobilization of radioactive and toxic metals in metal-contaminated subsurface environments. Therefore, laboratory and field studies were conducted to determine which microbial populations would respond to stimulation of Fe(III) reduction in the sediments of sandy aquifers. In laboratory studies, the addition of either various organic electron donors or electron shuttle compounds stimulated Fe(III) reduction and resulted in Geobacter sequences becoming important constituents of the Bacterial 16S rDNA sequences that could be detected with PCR amplification and denaturing gradient gel electrophoresis (DGGE). Quantification of Geobacteraceae sequences with a PCR most-probable-number technique indicated that the extent to which numbers of Geobacter increased was related to the degree of stimulation of Fe(III) reduction. Geothrix species were also enriched in some instances, but were orders of magnitude less numerous than Geobacter species. Shewanella species were not detected, even when organic compounds known to be electron donors for Shewanella species were used to stimulate Fe(III) reduction in the sediments. Geobacter species were also enriched in two field experiments in which Fe(III) reduction was stimulated with the addition of benzoate or aromatic hydrocarbons. The apparent growth of Geobacter species concurrent with increased Fe(III) reduction suggests that Geobacter species were responsible for much of the Fe(III) reduction in all of the stimulation approaches evaluated in three geographically distinct aquifers. Therefore, strategies for subsurface remediation that involve enhancing the activity of indigenous Fe(III)-reducing populations in aquifers should consider the physiological properties of Geobacter species in their treatment design.

Microbial Ecology↗