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The ecology of the soft-bottom benthos of San Francisco Bay: a community profile

This profile, part of a series of profiles concerning coastal habitats of the United States, is a detailed examination of the soft-bottom benthos of San Francisco Bay. A U.S. Fish and Wildlife Service and California Department of Fish and Game report (1979) entitled "Protection and Restoration of San Francisco Bay Fish and Wildlife Habitat" provides clear recognition of the importance of intertidal and subtidal soft-bottom habitats and their associated organisms to the bay's birds and fishes and to the overall functioning of the estuary. The purpose of this profile is to provide a description of the structure and functioning of the benthic community in San Francisco Bay (exclusive of its tidal marshes, which are discussed by M. Josselyn [1983] in another profile). The habitats covered in this volume include all nonvegetated soft-bottom intertidal and subtidal areas of the bay between the Golden Gate and the mouths of the Sacramento and San Joaquin Rivers to the northeast, and to the southern extremity of the bay. The profile provides a reference to the scientific information concerning the animals and plants of the bay's benthic communities, their importance to the bay ecosystem, and their value as a resource measured in human terms. Because there have been few process-oriented studies of the benthos of San Francisco Bay (e.g., field and laboratory rate-measurement experiments), the material presented herein is largely descriptive. Nonetheless, we have described the processes that interconnect the various physical, chemical, and biological components of the benthic environment, and the important couplings between this environment and the water column above, with reference to research results from other estuaries where necessary. We consider the role of the benthic community as a food source for fish, aquatic birds, and humans; as a consumer or degrader of organic materials including wastes; as a recycler of minerals and nutrients; and as an accumulator of pollutants.

California↗

U.S. Geological Survey climate and land use change science strategy—A framework for understanding and responding to global change

Executive Summary The U.S. Geological Survey (USGS), a nonregulatory Federal science agency with national scope and responsibilities, is uniquely positioned to serve the Nation’s needs in understanding and responding to global change, including changes in climate, water availability, sea level, land use and land cover, ecosystems, and global biogeochemical cycles. Global change is among the most challenging and formidable issues confronting our Nation and society. Scientists agree that global environmental changes during this century will have far-reaching societal implications (Intergovernmental Panel on Climate Change, 2007; U.S. Global Change Research Program, 2009). In the face of these challenges, the Nation can benefit greatly by using natural science information in decisionmaking. Since the passage of the U.S. Global Change Research Act of 1990, the USGS has made substantial scientific contributions to understanding the interactive living and nonliving components of the Earth system. USGS natural science activities have led to fundamental advances in observing and understanding climate and land-cover change and the effects these changes have on ecosystems, natural-resource availability, and societal sustainability. Most of these major advances were pursued in partnership with other organizations within and outside the Department of the Interior. The inherent value of partnerships with other U.S. Global Change Research Program agencies and natural-resource managers is emphasized in all aspects of the planning and implementation of this Science Strategy for the coming decade. Over the next 10 years, the USGS will make substantial contributions to understanding how Earth systems interact, respond to, and cause global change. The USGS will work with science partners, decisionmakers, and resource managers at local to international levels (including Native American tribes) to improve understanding of past and present change; develop relevant forecasts; and identify those lands, resources, and communities most vulnerable to global change processes. Science will play an essential role in helping communities and land and resource managers understand local to global implications, anticipate effects, prepare for changes, and reduce the risks associated with decisionmaking in a changing environment. USGS partners and stakeholders will benefit from the data, predictive models, and decision-support products and services resulting from the implementation of this strategy. This Science Strategy recognizes core USGS strengths that are applied to key societal problems. It establishes seven goals for USGS global change science and strategic actions that may be implemented in the short term (1–5 years) and the longer term (5–10 years) to improve our understanding of the following areas of inquiry: Rates, causes, and impacts of past global changes; The global carbon cycle; Biogeochemical cycles and their coupled interactions; Land-use and land-cover change rates, causes, and consequences; Droughts, floods, and water availability under changing land-use and climatic conditions; Coastal response to sea-level rise, climatic change, and human development; and Biological responses to global change. In addition to the seven thematic goals, we address the central role of monitoring in accordance with the USGS Science Strategy recommendation that global change research should rely on existing “…decades of observational data and long-term records to interpret consequences of climate variability and change to the Nation’s biological populations, ecosystems, and land and water resources” (U.S. Geological Survey, 2007, p. 19). We also briefly describe specific needs and opportunities for coordinating USGS global change science among USGS Mission Areas and address the need for a comprehensive and sustained communications strategy.

Circular↗

Preliminary Surficial Geology of the Dove Spring Off-Highway Vehicle Open Area, Mojave Desert, California

Introduction As part of a U.S. Geological Survey (USGS) monitoring plan to evaluate the environmental impact of off-highway vehicle (OHV) use on Bureau of Land Management (BLM) land in California, this report presents results of geologic studies in the Dove Spring OHV Open Area. This study produced baseline data, which when combined with historic and current patterns of land use, forms the basis for vegetation and wildlife monitoring designed to address the following questions: 1. Is the density and length of OHV routes increasing? 2. Are there cumulative effects of past and current OHV use associated with changes in the environmental integrity of soils, plants, and wildlife? 3. Is the spread of invasive species associated with levels of OHV use? 4. Is there a threshold of OHV impact that might be translated to management action by the BLM? The monitoring studies will be used to collect baseline environmental information to determine levels of environmental impact of OHV use. This approach will use a low-impact area as a proxy for pre-impact conditions (substituting space for time) to determine thresholds of OHV impacts beyond which environmental integrity is affected. Indicators of environmental integrity will emphasize factors that are fundamental to ecosystem structure and function and likely to be sensitive to OHV impacts. Surficial geology is studied because material properties such as texture and chemistry strongly control soil moisture and nutrient availability and therefore affect plant growth and distribution. An understanding of surficial geology can be used to predict and extrapolate soil properties and improve understanding of vegetation assemblages and their distribution. In the present study, vegetation associations may be examined as a function of surficial geology as well as other environmental variables such as slope, aspect, NRCS (National Resources Conservation Service) soil classification, elevation, and land-use history. Ground measurements of vegetation, biological soil crusts, compaction, and other information may be correlated with land use to identify possible ecological thresholds in OHV use that require monitoring. Surficial geology is relevant for several other studies of OHV impact, such as soil compaction, dust emissions, and acceleration of erosion. Compaction, reduced infiltration, and accelerated erosion have been documented in Dove Spring Canyon because of OHV use (Snyder and others, 1976) and elsewhere in the Mojave Desert (e.g., Webb, 1983; Langdon, 2000). A surficial geologic map enables the use of geomorphic process models, which when combined with measured soil properties, such as texture, nutrient chemistry, and bulk density, allows spatial extrapolation of the properties. Maps can be produced that predict compaction susceptibility, moisture conditions, dust emissions, flood hazards, and erodibility, among other applications.

Open-File Report↗

Recommended methods for range-wide monitoring of prairie dogs in the United States

One of the greatest challenges for conserving grassland, prairie scrub, and shrub-steppe ecosystems is maintaining prairie dog populations across the landscape. Of the four species of prairie dogs found in the United States, the Utah prairie dog (Cynomys parvidens) is listed under the Endangered Species Act (ESA) as threatened, the Gunnison's prairie dog (C. gunnisoni) is a candidate for listing in a portion of its range, and the black-tailed prairie dog (C. ludovicianus) and white-tailed prairie dog (C. leucurus) have each been petitioned for listing at least once in recent history. Although the U.S. Fish and Wildlife Service (USFWS) determined listing is not warranted for either the black-tailed prairie dog or white-tailed prairie dog, the petitions and associated reviews demonstrated the need for the States to monitor and manage for self-sustaining populations. In response to these findings, a multi-State conservation effort was initiated for the nonlisted species which included the following proposed actions: (1) completing an assessment of each prairie dog species in each State, (2) developing a range-wide monitoring protocol for each species using a statistically valid sampling procedure that would allow comparable analyses across States, and (3) monitoring prairie dog status every 3-5 years depending upon the species. To date, each State has completed an assessment and currently is monitoring prairie dog status; however, for some species, the inconsistency in survey methodology has made it difficult to compare data year-to-year or State-to-State. At the Prairie Dog Conservation Team meeting held in November 2008, there was discussion regarding the use of different methods to survey prairie dogs. A recommendation from this meeting was to convene a panel in a workshop-type forum and have the panel review the different methods being used and provide recommendations for range-wide monitoring protocols for each species of prairie dog. Consequently, the Western Association of Fish and Wildlife Agencies (WAFWA), in coordination with USFWS and U.S. Geological Survey (USGS), hosted a prairie dog species survey methodology workshop January 25-28, 2010 in Fort Collins, Colorado. The workshop provided all WAFWA partners and interested parties the opportunity to present their survey methodology to a review panel made up of experts in the fields of quantitative biology, population biology, species biology, and biostatistics. This report presents the panel's survey methodology recommendations for each of the four species of prairie dogs found in the United States and, for the black-tailed prairie dog, a list of action items to facilitate implementation of the recommended methodology.

Scientific Investigations Report↗

Submersed aquatic vegetation in Chesapeake Bay: Sentinel species in a changing world

Chesapeake Bay has undergone profound changes since European settlement. Increases in human and livestock populations, associated changes in land use, increases in nutrient loadings, shoreline armoring, and depletion of fish stocks have altered the important habitats within the Bay. Submersed aquatic vegetation (SAV) is a critical foundational habitat and provides numerous benefits and services to society. In Chesapeake Bay, SAV species are also indicators of environmental change because of their sensitivity to water quality and shoreline development. As such, SAV has been deeply integrated into regional regulations and annual assessments of management outcomes, restoration efforts, the scientific literature, and popular media coverage. Even so, SAV in Chesapeake Bay faces many historical and emerging challenges. The future of Chesapeake Bay is indicated by and contingent on the success of SAV. Its persistence will require continued action, coupled with new practices, to promote a healthy and sustainable ecosystem.

Chesapeake Bay↗

Strategies for managing the effects of urban development on streams

Urban development remains an important agent of environmental change in the United States. The U.S. population grew by 17 percent from 1982 to 1997, while urbanized land area grew by 47 percent, suggesting that urban land consumption far outpaced population growth (Fulton and others, 2001; Sierra Club, 2003; American Farmland Trust, 2009). Eighty percent of Americans now live in metropolitan areas. Each American effectively occupies about 20 percent more developed land (for housing, schools, shopping, roads, and other related services) than 20 years ago (Markham and Steinzor, 2006). Passel and Cohn (2008) predict a dramatic 48 percent increase in the population of the United States from 2005 to 2050. The advantages and challenges of living in these developed areas—convenience, congestion, employment, pollution—are part of the day-to-day realities of most Americans. Nowhere are the environmental changes associated with urban development more evident than in urban streams. The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program investigation of the effects of urban development on stream ecosystems (EUSE) during 1999–2004 provides the most spatially comprehensive analysis of stream impacts of urban development that has been completed in the United States. A nationally consistent study design was used in nine metropolitan areas of the United States—Portland, Oregon; Salt Lake City, Utah; Birmingham, Alabama; Atlanta, Georgia; Raleigh, North Carolina; Boston, Massachusetts; Denver, Colorado; Dallas, Texas; and Milwaukee, Wisconsin. A summary report published as part of the EUSE study describes several of these impacts on urban streams ( Coles and others, 2012 ).

Alabama;Colorado;Georgia;Massachusetts;North Carol↗

Annotated bibliography of scientific research on pygmy rabbits published from 1990 to 2020

Integrating recent scientific knowledge into management decisions supports effective natural resource management and can lead to better resource outcomes. However, finding and accessing scientific knowledge can be time consuming and costly. To assist in this process, the U.S. Geological Survey (USGS) is creating a series of annotated bibliographies on topics of management concern for western lands. Previously published reports introduced a methodology for preparing annotated bibliographies to facilitate the integration of recent, peer-reviewed science into resource management decisions. Therefore, relevant text from those efforts is reproduced here to frame the presentation. Sagebrush ecosystems throughout North America face management challenges including habitat loss and fragmentation. Brachylagus idahoensis (pygmy rabbits) are a sagebrush-obligate species that has experienced population declines and range contraction in recent decades. A disjunct population of pygmy rabbits in the Columbia Basin in Washington was listed as federally endangered in 2003. Due to their specialized habitat requirements and low dispersal ability, pygmy rabbits are a high priority for managers throughout their range. We compiled and summarized peer-reviewed journal articles, data products, and formal technical reports (such as U.S. Forest Service General Technical Reports and U.S. Geological Survey Open-File Reports) on pygmy rabbits published between January 1, 1990 and December 31, 2020. We first conducted a structured search of three reference databases and three government databases using the phrase “pygmy rabbit” or “ Brachylagus idahoensis .” We refined the initial list of products by removing (1) duplicates, (2) products not written in English, (3) publications that were not focused on North America, (4) publications that were not published as research, data products, or scientific review articles in peer-reviewed journals or as formal technical reports, and (5) products for which pygmy rabbits were not a research focus or for which the study did not present new data or findings about pygmy rabbits. We summarized each product using a consistent structure (background, objectives, methods, location, findings, and implications) and identified the management topics (for example, captive breeding, habitat characteristics, and population estimates) addressed by each product. We also noted which publications included new publicly available geospatial data. The review process for this annotated bibliography included an initial internal colleague review of each summary, requesting input on each summary from an author of the original publication, and a formal peer review. Our initial searches resulted in 2,285 total products, of which 105 met our criteria for inclusion. Sensitive/rare wildlife, behavior or demographics, site-scale habitat characteristics, habitat selection, and effects distances or spatial scale were the management topics most commonly addressed. The online version of this bibliography, Science for Resource Managers, will be searchable by topic, location, and year; it will include links to each original publication, where available. The studies compiled and summarized here may inform planning and management actions that seek to maintain and restore sagebrush landscapes and associated native species across the western United States.

Open-File Report↗

Water-Quality and Fish-Community Data for the Niobrara National Scenic River, Nebraska, 2003-05

In 1991, a 76-mile reach of the Niobrara River in north-central Nebraska was designated as a National Scenic River (NSR). This reach of the river hosts a unique ecosystem that provides habitat for a diverse fish and wildlife population that include several threatened and endangered species. The Niobrara NSR also is a popular destination for campers, canoeists, kayakers, and tubers. Changes in surface-water quality, related to recreation, industrial and municipal discharge, and agricultural activities in the region have the potential to affect fish and wildlife populations within the Niobrara NSR. Additionally, water users may be at risk if elevated concentrations of chemical or biological contaminants are present in the waterway. The U.S. Geological Survey (USGS) and the National Park Service (NPS) began a 3-year cooperative study of water-quality characteristics in Niobrara NSR in 2003. During the study, water samples were collected for analysis of a suite of physical, chemical, and biological indicators of water quality in the Niobrara River. The resulting data have been published previously (Hitch and others, 2004; Hitch and others, 2005) and included: major ions, nutrients, trace elements, pesticides, organic (wastewater) compounds, bacteria, and suspended sediment. In addition to water-quality sampling, fish communities were sampled to identify the presence and diversity of species at selected sites (data available online in Annual Water Data Reports). These water-quality and fish-community data are summarized in this report. The data were collected to provide baseline information that will help NPS managers determine if changes in recreational activities, land-use practices, and other factors are affecting the Niobrara River.

Fact Sheet↗

Developing ecological criteria for prescribed fire in South Florida pine rockland ecosystems

The pine rocklands of South Florida, characterized by a rich herbaceous flora with many narrowly endemic taxa beneath an overstory of south Florida slash pine (Pinus elliottii var. densa), are found in three areas: the Miami Rock Ridge of southeastern peninsular Florida, the Lower Florida Keys, and slightly elevated portions of the southern Big Cypress National Preserve. Fire is an important element in these ecosystems, since in its absence the pine canopy is likely to be replaced by dense hardwoods, resulting in loss of the characteristic pineland herb flora. Prescribed fire has been used in Florida Keys pine forests since the creation of the National Key Deer Refuge (NKDR), with the primary aim of reducing fuels. Because fire can also be an effective tool in shaping ecological communities, we conducted a 4-year research study which explored a range of fire management options in NKDR. The intent of the study was to provide the Fish and Wildlife Service and other land managers with information regarding when and where to burn in order to perpetuate these unique forests. In 1998 we initiated a burning experiment in a randomized complete block design. Three treatments were to be carried out in a single well-defined block in each of two characteristic understory types during each year from 1998 through 2000. One understory type was characterized by a relatively sparse shrub layer and a well-developed herb layer ('open'), and the second had a dense shrub layer and poorly developed herb layer ('shrubby'). The three burn treatments were: (a) summer burn, (b) winter burn, and (c) no burn, or control. Three 1- ha plots were established in each block, and randomly assigned to the three treatments. Though the first year experimental burns were carried out without incident, constraints posed by external factors, including nationwide and statewide prohibitions on prescribed burning due to wildfires in other regions, delayed the experimental burns and precluded collection of postburn data on one third of the burns. Ultimately we burned only eleven plots, three in winter and eight in summer, over a four-year period from 1998 to 2001. Vegetation was sampled in a stratified, nested design within 18 plots. Trees were sampled in a 1.0-ha plot, shrubs in twenty 50-m2 circular (radius 4 m) subplots within the tree plot, and the herb layer in four circular 1-m2 quadrats (radius 0.57 m) within each subplot. The amount of fuel in the shrub layer was estimated by applying regression models to plant dimensional data, and ground layer fuel was estimated by a harvest method. The effects of Key deer herbivory on regeneration of the understory pine rockland plant community after fire was studied by monitoring inside and outside exclosures established within two of the six blocks. Pine trees constituted more than half (53.3%) of the biomass, but understory fine fuels comprised a surprisingly high proportion of total aboveground biomass. In the three blocks in which paired summer and winter burns were successfully conducted, the summer burns were more intense than the winter burns as judged by our indicators of fire intensity. Because of the differences in fire intensity between seasons, it was not possible to say whether observed differences in vegetation response between summer and winter burns were due to season or to fire intensity. The mortality of South Florida slash pine trees was greater after the summer burn than the winter burn in each block, but other vegetation responses were rarely as consistent. For instance, Metopium showed less recovery after summer burns in two blocks and after the winter burn in the third block. Moreover, there were instances in which alternative growth stages of the same species responded differently. Adult palms succumbed more frequently to summer than winter burns, and mortality of Coccothrinax exceeded that of Thrinax. In contrast, small palms recovered more readily after summer burns than winter burns. High in

Florida↗

Soil, environmental, and watershed measurements in support of carbon cycling studies in northwestern Mississippi

Measurements including soil respiration, soil moisture, soil temperature, and carbon export in suspended sediments from small watersheds were recorded at several field sites in northwestern Mississippi in support of hillslope process studies associated with the U.S. Geological Survey's Mississippi Basin Carbon Project (MBCP). These measurements were made to provide information about carbon cycling in agricultural and forest ecosystems to understand the potential role of erosion and deposition in the sequestration of soil organic carbon in upland soils. The question of whether soil erosion and burial constitutes an important net sink of atmospheric carbon dioxide is one hypothesis that the MBCP is evaluating to better understand carbon cycling and climate change. This report contains discussion of methods used and presents data for the period December 1996 through March 1998. Included in the report are ancillary data provided by the U.S. Department of Agriculture (USDA) ARS National Sedimentation Laboratory and U.S. Forest Service (USFS) Center for Bottomland Hardwoods Research on rainfall, runoff, sediment yield, forest biomass and grain yield. Together with the data collected by the USGS these data permit the construction of carbon budgets and the calibration of models of soil organic matter dynamics and sediment transport and deposition. The U.S. Geological Survey (USGS) has established cooperative agreements with the USDA and USFS to facilitate collaborative research at research sites in northwestern Mississippi.

Mississippi↗

Evidence for marine-driven, cyclical fluctuations in burrow-nesting seabird habitat on the Oregon Coast

Seabirds are among the most threatened birds globally, with the loss or deterioration of coastal breeding habitats posing a severe threat. Natural and anthropogenic disturbances substantially influence coastal ecosystems through erosion and vegetation loss, altering habitat for the wildlife species that depend on them. In addition to these disturbances, oceanographic processes may play an important role in shaping the vegetation at breeding habitats; however, there is limited information on how vegetative conditions for burrow nesting seabirds have changed over time, and whether these changes are related to specific oceanographic or climatic factors. The Oregon Coast National Wildlife Refuge Complex, USA (NWRC) is home to a diverse suite of 1.3 million nesting seabirds from 14 species, which provide valuable ecological, economic, and cultural services, including nutrient transfer to terrestrial habitats and ecotourism for local communities. Over the last 30 years, populations of several burrow nesting seabird species including tufted puffin ( Fratercula cirrhata ) and rhinoceros auklet ( Cerorhinca monocerata ), which breed on offshore islands, have sharply declined along the Oregon Coast. To better understand the potential factors driving these declines, we conducted a spatiotemporal analysis of an aspect of burrow nesting seabird habitat, vegetation cover, within the Oregon Coast NWRC. Specifically, we quantified vegetative cover on 16 islands from 1992 to 2022 using a combination of empirical data, historical aerial photography (1992–2005), and aerial photography from the National Agriculture Imagery Program (2005–2022). Results showed cyclical fluctuations in vegetation cover coast-wide, which were closely related to large scale oceanographic oscillations. Specifically, vegetation cover was negatively correlated with the winter Pacific Decadal Oscillation and positively correlated with the spring El Nino Southern Oscillation. We did not directly compare seabird population trends to vegetation trends; however, quantifying these long-term changes in vegetation at breeding habitats can contribute to our comprehensive understanding of the myriad factors influencing seabird population dynamics and conservation.

Oregon↗

Effects of current-use pesticides on amphibians

For many years, amphibians were understudied in the ecotoxicological literature. In 1989, the Canadian Wildlife Service published a comprehensive review of studies examining the effects of contaminants on amphibians (Power et al. 1989). Just 10 years later, the same organization published an updated review that included twice the number of studies (Pauli et al. 2000), indicating rapid growth in the field of amphibian ecotoxicology. However, Sparling et al. (2000) point out that the number of amphibian ecotoxicological studies remains modest relative to research utilizing other taxa. Relyea and Hoverman (2006) also report that amphibian data appear to be lagging behind other taxa, despite an increasing number of ecotoxicological studies involving freshwater ecosystems in general.

Book chapter↗

Patterns of water-quality variability in San Francisco Bay during the first six years of the regional monitoring program, 1993-1998

Monitoring Results presents data from the Status and Trends portion of the 1998 San Francisco Estuary Regional Monitoring Program for Trace Substances (RMP). A list of reports on Pilot and Special Studies, as well as other RMP related activities can be found at the end of this document. These reports provide perspective and insight on important contaminant issues identified by the RMP, and they describe results from projects that took advantage of RMP field operations. For a summary of the conditions of the Estuary see The Pulse . A print copy may also be ordered by contacting the San Francisco Estuary Institute (SFEI). In 1998, the San Francisco Regional Water Quality Control Board (Regional Board) and seventy-three federal, state, and local agencies and companies participated in the RMP as funders and service providers (Table 1.1). Participants also assist in directing the Program through input or participation on the Steering and Technical Review Committees. The RMP’s overall goal is to provide data and interpretation that helps to address certain information needs of the Regional Board. In general, these efforts fall under five major objectives which provide a framework for efforts to respond to more specific management questions. 1. Describe patterns and trends in contaminant concentration and distribution. 2. Describe general sources and loadings of contamination to the Estuary. 3. Measure contaminant effects on selected parts of the Estuary ecosystem. 4. Compare monitoring information to relevant water quality objectives and other guidelines. 5. Synthesize and distribute information from a range of sources to present a more complete picture of the sources, distribution, fates, and effects of contaminants in the Estuary ecosystem.

California↗

Deepwater Program: Studies of Gulf of Mexico lower continental slope communities related to chemosynthetic and hard substrate habitats

This report summarizes research funded by the U.S. Geological Survey (USGS) in collaboration with the University of North Carolina at Wilmington (UNCW) on the ecology of deep chemosynthetic communities in the Gulf of Mexico. The research was conducted at the request of the U.S. Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE; formerly Minerals Management Service) to complement a BOEMRE-funded project titled "Deepwater Program: Investigations of Chemosynthetic Communities on the Lower Continental Slope of the Gulf of Mexico." The overall research partnership, known as "Chemo III," was initiated to increase understanding of the distribution, structure, function, and vulnerabilities of these poorly known associations of animals and microbes for water depths greater than 1,000 meters (m) in the Gulf of Mexico. Chemosynthetic communities rely on carbon sources that are largely independent of sunlight and photosynthetic food webs. Despite recent research directed toward chemosynthetic and deep coral (for example, Lophelia pertusa) based ecosystems, these habitats are still poorly studied, especially at depths greater than 1,000 m. With the progression into deeper waters by fishing and energy industries, developing sufficient knowledge to manage these deep ecosystems is essential. Increased understanding of deep-sea communities will enable sound evaluations of potential impacts and appropriate mitigations.

Gulf Of Mexico↗

Acid rain in Shenandoah National Park, Virginia

Visitors to Shenandoah National Park (SNP) enjoy the animal and plant life and the scenery but may not realize how vulnerable these features are to various threats, such as invasion of exotic plants and insects, improper use of park resources by humans, and air and water pollution. The National Park Service strives to protect natural resources from such threats to ensure that the resources will be available for enjoyment now and in the future. Because SNP has limited influence over the air pollution that envelops the region, acidic deposition--commonly known as acid rain--is one of the more challenging threats facing park managers. With the help of U.S. Geological Survey (USGS) scientists, park managers can understand how acid rain interacts with ground- and surface-water resources, which enables them to explain why reductions in air pollution can help preserve park resources. Such understanding also provides essential insight into ecosystem processes, as managers strive to unravel and resolve other environmental problems that are interrelated to acid rain.

Virginia↗

Changes in nitrogen loading to the Northeast Creek Estuary, Bar Harbor, Maine, 2000 to 2010

Since 1999, the U.S. Geological Survey and the National Park Service have been monitoring land use and nitrogen loading in a 26.3-square-kilometer (10-square-mile) estuarine watershed at Acadia National Park, Mount Desert Island, Maine. The initial study linking land use and nitrogen loads entering the Northeast Creek estuary was completed in 2000, and findings were used to develop simulations of nitrogen loading to the estuary, thereby helping to inform local land-use planning decisions. At that time, the amount of nitrogen entering the Northeast Creek estuary was relatively small, and no evidence of nutrient-related degradation was observed in the Ruppia -dominated estuarine ecosystem. A new round of water-quality monitoring and streamflow measurements was conducted to determine nitrogen loading from 2008 to 2011 as a means to evaluate the effects of increased rural residential housing within the watershed since 2000. On the basis of a 2.6-percent increase in residential-housing land use in the watershed from 2000 to 2010, simulations of nitrogen export predicted a 7-percent increase in nitrogen loading to Northeast Creek. The measurement-based loads estimated for the Northeast Creek tributaries, however, increased much more than predicted, from 1.89 kilograms per hectare per year (kg/ha/yr) in 2000 to 3.12 kg/ha/yr in the time period centered on 2010—a 66-percent increase. This increase is likely primarily a result of the prevalence of much wetter conditions during the 2008–11 sampling period than during the earlier sampling period. In addition to increasing the physical transport of nitrogen in the watershed, wet climatic conditions have been shown in other studies to increase the rates of biotic and abiotic processes that control nitrogen export from northern-latitude forested watersheds. The new loading estimates, however, also support the possibility that some portion of the increase in nitrogen loading results from the observed land-use changes, and that the increase in residential housing has, in fact, contributed to the observed increase in nitrogen loading.

Maine↗

Bug flows: Don’t count your midges until they hatch

Usually when people hear about a “bug problem” it’s due to an undesirable overabundance of insects (think plague of locusts). In the Colorado River in Grand Canyon, however, we are faced with the opposite predicament: the river is essentially devoid of bugs. Aquatic insects are a fundamental component of a healthy river ecosystem. Most aquatic insects spend their juvenile life stages (egg, larva, pupa) in the river and their winged adult life stage flying along the riparian corridor. Throughout these metamorphoses one thing is for certain: aquatic insects are prey for fish, birds, bats, lizards, and even other invertebrates. In Grand Canyon, food web studies conducted by the US Geological Survey (USGS) have demonstrated that populations of both native and sport fish are food limited (Cross et al. 2013, Kennedy et al. 2013). In other words, fish in Grand Canyon are consistently facing a calorie deficit. Indeed, the US Fish and Wildlife Service has cited the inadequate and unreliable food supply as the single greatest problem facing endangered Humpback Chub populations in the Grand Canyon (USFWS 2019).

Boatman's Quarterly Review↗

Trip report: pilot study of factors linking watershed function and coastal ecosystem health in American Samoa

Coral reef resources in the territory of American Samoa face significant problems from overfishing, non-point source pollution, global warming, and continuing population growth and development. The islands are still relatively isolated relative to other parts of the Pacific and have managed to avoid some of the more devastating invasive species that have reached other archipelagoes. As a result, there are opportunities for collaborative and integrative research and monitoring programs to help restore and maintain biodiversity and functioning natural ecosystem in the archipelago. We found that the “Ridge to Reef” paradigm already exists in American Samoa, with a high degree of interagency cooperation and efficient use of limited resources already taking place in the Territory. USGS may be able to make contributions as a partner organization in the Coral Reef Advisory Group (CRAG) through deployment of sediment monitoring instrumentation to supplement stream monitoring by the American Samoa Environmental Protection Agency, by providing high resolution vegetation and land-use maps of main islands, by providing additional support to the American Samoa Department of Marine and Wildlife Resources and the National Park Service for monitoring of invasive species, by working with members of CRAG to initiate sediment transport studies on Samoan reefs, and by developing new projects on the effects of bacterial contamination and pollutants on coral reef physiology and demography.

Open-File Report↗