SEARCH · USGS Science

Results for “Diversity and Distributions”

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 955 records · Page 53Linked to original sources

USGS1985

Stratigraphic and interregional changes in Pennsylvanian coal-swamp vegetation: Environmental inferences

Quantitative analysis of Pennsylvanian coal-swamp vegetation provides a means of inferring organization and structure of communities. Distribution of these communities further provides inferences about environmental factors, including paleoclimate. Our observations are based on in situ, structurally preserved peat deposits in coal-ball concretions from 32 coal seams in the eastern one-half of the United States and from several seams in western Europe and on spore assemblages from more than 150 seams. There were three times of particularly significant and nearly synchronous vegetational changes in the Midcontinent and Appalachian coal regions during the Pennsylvanian Period. Each was different in kind and magnitude. The first marked changes occurred during the early part of the Middle Pennsylvanian with the fluctuating decline in the high level of lycopod dominance. The abundance of cordaites increased. There was a rise in the occurrences of the lycopod herbs to form intercalated marshlands and an overall increase in floral diversity. Changes ensuing from this time also include shifts in dominant species of lycopod trees and a sustained rise in abundance and diversity of tree-fern spores. The next significant time of change was during the middle part of the Middle Pennsylvanian, representing both a culmination of earlier trends and expansions of cordaites in the Midcontinent where there was a maximum change in species without net loss of diversity. Tree ferns and medullosan pteridosperms attained subdominant levels of abundance and diverse lycopod species dominated except in the Atokan-Desmoinesian transition of the Midcontinent. The third and sharpest break occurred near the Middle—Late Pennsylvanian boundary when extinctionsof the dominant, coal-swamp lycopods allowed development of tree-fern dominance. The Late Pennsylvanian coal swamps apparently were colonized or recolonized mainly by species from outside coal swamps rather than by the survivor populations of the Middle Pennsylvanian swamps. Paralleling the changes in floras through the Pennsylvanian are changes in preservational aspects of the peat. These include a decline in shoot/root ratios from approximately 1 to < 1 during the first time of vegetational changes and a rise in this ratio during the second; there was a parallel rise and fall in fusain abundance and a rise in wood/periderm ratios. The stratigraphic distribution of identified coal resources in the United States is interpreted as largely dependent on net changes in relative wetness of Pennsylvanian coal swamps, a pattern of drying during the first period of vegetational change, followed by a concomitant increase in continuous wet climate with brackish influence in the Midcontinent during the second; this was followed by a time of extreme moisture stress bringing on the third, and most severe, vegetational change.

International Journal of Coal Geology↗

USGS2015

Climate change impacts on ecosystems and ecosystem services in the United States: Process and prospects for sustained assessment

The third United States National Climate Assessment emphasized an evaluation of not just the impacts of climate change on species and ecosystems, but also the impacts of climate change on the benefits that people derive from nature, known as ecosystem services. The ecosystems, biodiversity, and ecosystem services component of the assessment largely drew upon the findings of a transdisciplinary workshop aimed at developing technical input for the assessment, involving participants from diverse sectors. A small author team distilled and synthesized this and hundreds of other technical input to develop the key findings of the assessment. The process of developing and ranking key findings hinged on identifying impacts that had particular, demonstrable effects on the U.S. public via changes in national ecosystem services. Findings showed that ecosystem services are threatened by the impacts of climate change on water supplies, species distributions and phenology, as well as multiple assaults on ecosystem integrity that, when compounded by climate change, reduce the capacity of ecosystems to buffer against extreme events. As ecosystems change, such benefits as water sustainability and protection from storms that are afforded by intact ecosystems are projected to decline across the continent due to climate change. An ongoing, sustained assessment that focuses on the co-production of actionable climate science will allow scientists from a range of disciplines to ascertain the capability of their forecasting models to project environmental and ecological change and link it to ecosystem services; additionally, an iterative process of evaluation, development of management strategies, monitoring, and reevaluation will increase the applicability and usability of the science by the U.S. public.

Climatic Change↗

USGS2023

Evaluating regional length limits in freshwater fisheries

Length limits are often used in recreational fisheries management to prevent overharvest and manipulate fish size distributions. These regulations are ideally customized to meet water-specific stock dynamics and fishery objectives. However, in districts with numerous discrete waters, fisheries are commonly managed with a universal regional regulation. Evaluating alternative regional length limits requires consideration of management objectives that may not be important at the single-system level but that emerge as relevant at the regional scale, such as uniformity of regional harvest, diversity of average catch sizes, and opportunity to harvest. We developed a flexible tool for evaluating regional length limits. The tool joins the well-established Beverton–Holt yield-per-recruit model with elements of decision-support methods. The model quantifies regional management objectives as utility functions that are weighted and summed into a single value used to evaluate alternative length limits. The flexibility of the tool stems from its capacity to consider a mixture of stock parameters and associated uncertainty to evaluate multiple length limits, weighting an array of regional fishery objectives quantified by various performance metrics. This adjustability affords flexibility to consider a diversity of options that can stimulate innovation in setting regional length limits. We demonstrate the model by evaluating varying length limits on fishery objectives related to the management of hypothetical yellow perch ( Perca flavescens ) populations and real black crappie ( Pomoxis nigromaculatus ) populations.

Canadian Journal Fisheries and Aquatic Sciences↗

USGS2015

Arctic biodiversity: Increasing richness accompanies shrinking refugia for a cold-associated tundra fauna

As ancestral biodiversity responded dynamically to late-Quaternary climate changes, so are extant organisms responding to the warming trajectory of the Anthropocene. Ecological predictive modeling, statistical hypothesis tests, and genetic signatures of demographic change can provide a powerful integrated toolset for investigating these biodiversity responses to climate change, and relative resiliency across different communities. Within the biotic province of Beringia, we analyzed specimen localities and DNA sequences from 28 mammal species associated with boreal forest and Arctic tundra biomes to assess both historical distributional and evolutionary responses and then forecasted future changes based on statistical assessments of past and present trajectories, and quantified distributional and demographic changes in relation to major management regions within the study area. We addressed three sets of hypotheses associated with aspects of methodological, biological, and socio-political importance by asking (1) what is the consistency among implications of predicted changes based on the results of both ecological and evolutionary analyses; (2) what are the ecological and evolutionary implications of climate change considering either total regional diversity or distinct communities associated with major biomes; and (3) are there differences in management implications across regions? Our results indicate increasing Arctic richness through time that highlights a potential state shift across the Arctic landscape. However, within distinct ecological communities, we found a predicted decline in the range and effective population size of tundra species into several discrete refugial areas. Consistency in results based on a combination of both ecological and evolutionary approaches demonstrates increased statistical confidence by applying cross-discipline comparative analyses to conservation of biodiversity, particularly considering variable management regimes that seek to balance sustainable ecosystems with other anthropogenic values. Refugial areas for cold-adapted taxa appear to be persistent across both warm and cold climate phases and although fragmented, constitute vital regions for persistence of Arctic mammals.

Ecosphere↗

USGS2025

Evaluating mountain goat population structure in Glacier National Park and Waterton Lakes National Park

Mountain goats are an iconic, climate-sensitive species across their North American alpine range. Among its nearly complete complement of native wildlife, no single species embodies Glacier National Park (GNP) more than the mountain goat. They play an important role as an alpine food source for many of the park’s carnivores including wolverines, mountain lions, and grizzly bears. Mountain goats face many increasing threats, particularly at the southern extent of their range. These include changes in precipitation and temperature, shifts in forage and fire frequency and intensity, and rapidly increasing visitation and recreation. Although the high latitude and elevations of GNP offer refugia, the mountain goat population likely declined between 2008 and 2019 and may also have a smaller distribution. In Montana, many other native mountain goat populations are also declining or have disappeared entirely. Using a combination of staff and citizen scientists, we collected fecal pellets across GNP in Montana, USA, and adjoining Waterton Lakes National Park (WLNP) in Alberta, Canada, between 2019 and 2023. We used genotypes of 6 to 19 loci microsatellites to identify individuals and assess isolation by distance, genetic structure, and genetic diversity. We found no evidence of genetic structure and only limited isolation by distance. This suggests that mountain goats in GNP and WLNP can be considered a single population, so samples can be combined across the area to estimate a single population size. Genetic diversity was similar to recent mountain goat studies conducted in other regions; allelic richness was 3.54 and inbreeding coefficients ( F IS ) ranged from 0.01–0.19, with values >0.11 only in the Livingston Range in the northwest of the study area. The high F IS in the Livingston Range suggests several closely related groups with little interchange, and perhaps a recent decrease in gene flow, both of which are consistent with a recent population decline in that area. We detected a high number of closely related individuals throughout our study area, consistent with the high adult survival, low reproductive success life history of goats, but also suggesting that we sampled much of the overall population.

Alberta, Montana↗

USGS2013

Determination of flow losses in the Cape Fear River between B. Everett Jordan Lake and Lillington, North Carolina, 2008-2010

During 2008-2010, the U.S. Geological Survey conducted a hydrologic investigation in cooperation with the Triangle J Council of Governments Cape Fear River Flow Study Committee and the North Carolina Division of Water Resources to collect hydrologic data in the Cape Fear River between B. Everett Jordan Lake and Lillington in central North Carolina to help determine if suspected flow losses occur in the reach. Flow loss analyses were completed by summing the daily flow releases at Jordan Lake Dam with the daily discharges at Deep River at Moncure and Buckhorn Creek near Corinth, then subtracting these values from the daily discharges at Cape Fear River at Lillington. Examination of long-term records revealed that during 10,227 days of the 1983-2010 water years, 408 days (4.0 percent) had flow loss when conditions were relatively steady with respect to the previous day's records. The flow loss that occurred on these 40 days ranged from 0.49 to 2,150 cubic feet per second with a median flow loss of 37.2 cubic feet per second. The months with the highest number of days with flow losses were June (16. percent), September (16.9 percent), and October (19.4 percent). A series of synoptic discharge measurements made on six separate days in 2009 provided "snapshots" of overall flow conditions along the study reach. The largest water diversion is just downstream from the confluence of the Haw and Deep Rivers, and discharges substantially decrease in the main stem downstream from the intake point. Downstream from Buckhorn Dam, minimal gain or loss between the dam and Raven Rock State Park was noted. Analyses of discharge measurements and ratings for two streamgages-one at Deep River at Moncure and the other at Cape Fear River at Lillington-were completed to address the accuracy of the relation between stage and discharge at these sites. The ratings analyses did not indicate a particular time during the 1982-2011 water years in which a consistent bias occurred in the computations of discharge records that would indicate false flow losses. A total of 34 measured discharges at a streamgage on the Haw River below B. Everett Jordan Lake near Moncure were compared with the reported hourly flow releases from Jordan Lake Dam. Because 28 of 34 measurements were within plus or minus 10 percent of the hourly flow releases reported by the U.S Army Corps of Engineers, use of the current discharge computation tables for reporting Jordan Lake Dam flow releases is generally supported. A stage gage was operated on the Cape Fear River at Buckhorn Dam near Corinth to collect continuous stage-only records. Throughout the study period, flow over the dam was observed along its length, and flow loss within the study reach is not attributed to river-level fluctuations at the dam. Water-use information and (or) data were obtained for five industrial facilities, a regional power utility, two municipalities, one small hydropower facility on the Deep River, and one quarry operation also adjacent to the Deep River. The largest water users are the regional power producer, a small hydropower operation, and the two municipalities. The total water-use diversions for these facilities range from almost 25.5 to 38.5 cubic feet per second (39.5 to 59.5 million gallons per day) during the winter and summer periods, respectively. This range is equivalent to 69 to 104 percent of the 37 cubic feet per second median flow loss. The Lockville hydropower station is on the Deep River about 1 mile downstream from the streamgage near Moncure. Run-of-river operations at the facility do not appear to affect flow losses in the study reach. The largest water user in the study area is a regional power producer at a coal-fired power-generation plant located immediately adjacent to the Cape Fear River just downstream from the confluence of the Haw an Deep Rivers. Comparisons of daily water withdrawals, sup-plied by the regional power producer, and discharge records at a streamgage on the diversion canal indicated many days when consumption exceeded the producer's estimates for the cooling towers. Uncertainty surrounding reasonable estimates of consumption remained in effect at the end of the study. Data concerning evaporative losses were compiled using two approaches-an analysis of available pan-evaporation data from a National Weather Service cooperative observer station in Chapel Hill, North Carolina; and a compilation of reference open-water evaporation computed by the State Climate Office of North Carolina. The potential flow loss by evaporation from the main stem and the Deep River was estimated to be in the range of 4 to 14 cubic feet per second during May through October, equivalent to 10 to 38 percent of the 37 cubic feet per second median flow loss. Daily water-use diversions and evaporation losses were compared to flow-loss occurrences during the period April 2008 through September 2010. In comparing the surface-water, water-use, and evaporation data compiled for 2008-2010, it is evident that documented water diversions combined with flow losses by open-water evaporation can exceed the net flow gain in the study area and result in flow losses from the reach. Analysis of data from a streamgage downstream from the regional power plant on the diversion canal adjacent to the Cape Fear River provided insight into the occurrence of an apparent flow loss at the streamgage at Lillington. Assessment of the daily discharges and subsequent hydrographs for the canal streamgage indicated at least 24 instances during the study when the flows suddenly changed by magnitudes of 100 to more that 200 cubic feet per second, resulting in a noted time-lag effect on the downstream discharges at the Lillington streamgage, beginning 8 to 16 hours after the sudden flow change. A fiber-optic distributed temperature-sensing survey was conducted on the Cape Fear River at the Raven Rock State Park reach August 12-14, 2009, to determine if the presence of diabase dikes were preferentially directing groundwater discharge. No temperature anomalies of colder water were measured during the survey, which indicated that at the time of the survey that particular reach of the Cape Fear River was a "no-flow" or losing stream. An aerial thermal-infrared survey was conducted on the Haw and Cape Fear Rivers on February 27, 2010, from Jordan Lake Dam to Lillington to qualitatively delineate areas of groundwater discharge on the basis of the contrast between warm groundwater discharge and cold surface-water temperatures. Dis-charge generally was noted as diffuse seepage, but in a few cases springs were detected as inflow at a discrete point of discharge. Two reaches of the Cape Fear River (regional power plant and Bradley Road reaches) were selected for groundwater monitoring with a transect of piezometers installed within the flood plain. Groundwater-level altitudes at these reaches were analyzed for 1 water year (October 1, 2009, to September 30, 2010). Data collected as part of this study represent only a brief period of time and may not represent all conditions and all years; however, the data indicate that, during the dry summer months, the Cape Fear River within the study area is losing an undetermined quantity of water through seepage. Analyses completed during this investigation indicate a study reach with complex flow patterns affected by numerous concurrent factors resulting in flow losses. The causes of flow loss could not be solely attributed to any one factor. Among the factors considered, the occurrences of water diversions and evaporative losses were determined to be sufficient on some days (particularly during the base-flow period) to exceed the net gain in flows between the upstream and downstream ends of the study area. Losses by diversions and evaporation can exceed the median flow loss of 3 cubic feet per second, which indicates that flow loss from the study reach is real. Groundwater data collected during 2009-2010 indicate the possibility of localized flow loss during the summer, particularly in the impounded reach above Buckhorn Dam. However, no indication of unusual patterns was noted that would cause substantial flow loss by groundwater and surface-water interaction at the river bottom.

North Carolina↗

USGS2022

Seed menus: An integrated decision-support framework for native plant restoration in the Mojave Desert

The combination of ecosystem stressors, rapid climate change, and increasing landscape-scale development has necessitated active restoration across large tracts of disturbed habitats in the arid southwestern United States. In this context, programmatic directives such as the National Seed Strategy for Rehabilitation and Restoration have increasingly emphasized improved restoration practices that promote resilient, diverse plant communities and enhance native seed reserves. While decision-support tools have been implemented to support genetic diversity by guiding seed transfer decisions based on patterns in local adaptation, less emphasis has been placed on identifying priority seed mixes composed of native species assemblages. Well-designed seed mixes can provide foundational ecosystem services including resilience to disturbance, resistance to invasive species, plant canopy structure to facilitate natural seedling recruitment, and habitat to support wildlife and pollinator communities. Drawing from a newly developed dataset of species distribution models for priority native plant taxa in the Mojave Desert, we created a novel decision support tool by pairing spatial predictions of species habitat with a database of key species traits including life history, flowering characteristics, pollinator relationships, and propagation methods. This publicly available web application, Mojave Seed Menus, helps restoration practitioners generate customized seed mixes for native plant restoration in the Mojave Desert while emphasizing key species traits. Our application forms an essential part of an integrated Mojave Desert restoration program designed to help practitioners identify species to include in local seed mixes and nursery stock development while accounting for local adaptation by identifying appropriate seed sources within key restoration species.

Arizona, California, Nevada, Utah↗

USGS2015

Guidelines for evaluating performance of oyster habitat restoration

Restoration of degraded ecosystems is an important societal goal, yet inadequate monitoring and the absence of clear performance metrics are common criticisms of many habitat restoration projects. Funding limitations can prevent adequate monitoring, but we suggest that the lack of accepted metrics to address the diversity of restoration objectives also presents a serious challenge to the monitoring of restoration projects. A working group with experience in designing and monitoring oyster reef projects was used to develop standardized monitoring metrics, units, and performance criteria that would allow for comparison among restoration sites and projects of various construction types. A set of four universal metrics (reef areal dimensions, reef height, oyster density, and oyster size–frequency distribution) and a set of three universal environmental variables (water temperature, salinity, and dissolved oxygen) are recommended to be monitored for all oyster habitat restoration projects regardless of their goal(s). In addition, restoration goal-based metrics specific to four commonly cited ecosystem service-based restoration goals are recommended, along with an optional set of seven supplemental ancillary metrics that could provide information useful to the interpretation of prerestoration and postrestoration monitoring data. Widespread adoption of a common set of metrics with standardized techniques and units to assess well-defined goals not only allows practitioners to gauge the performance of their own projects but also allows for comparison among projects, which is both essential to the advancement of the field of oyster restoration and can provide new knowledge about the structure and ecological function of oyster reef ecosystems.

Restoration Ecology↗

USGS2005

Inventory of the mosses, liverworts, and lichens of Olympic National Park, Washington- Species list

The identification of non-vascular cryptogam species (lichens, mosses, liverworts, and hornworts) is especially challenging because of their small size, their often microscopic or chemical distinguishing features, and their enormous diversity. Consequently, they are a poorly known component of Olympic National Park, despite their ecological and aesthetic importance. This project is the first attempt at a systematic, comprehensive survey of non-vascular cryptogams in the Park and presents the current species list with descriptions of the substrate and vascular vegetation type where they were observed. The authors strove to collect from as many park environments as feasible, and distributed collections along important environmental gradients in different regions of the park using vascular vegetation as an environmental indicator. They also collected opportunistically when interesting habitats or microhabitats were encountered. Finally, the authors updated the nomenclature in the Park’s previous collection of nonvascular plants. This study identified approximately 13,200 bryophyte and lichen species, adding approximately 425 new species to the Olympic National Park Herbarium. These data, combined with select literature reports and personal data from Martin and Karen Hutten, added more than 350 species to the previously documented Olympic Peninsula lichen and bryophyte list. The authors discuss the list in a local, regional, and global context of rarity, as well as cryptogam conservation and further work needed in Olympic National Park. The improved inventory of Olympic National Park cryptogams represented by this project enables Olympic National Park to protect populations of rare and sensitive species, assess the damage caused by illegal harvest, and contribute information to the Bureau of Land Management and U.S. Forest Service Sensitive Species Programs.

Scientific Investigations Report↗

USGS2015

The importance of scaling for detecting community patterns: success and failure in assemblages of introduced species

Community saturation can help to explain why biological invasions fail. However, previous research has documented inconsistent relationships between failed invasions ( i.e ., an invasive species colonizes but goes extinct) and the number of species present in the invaded community. We use data from bird communities of the Hawaiian island of Oahu, which supports a community of 38 successfully established introduced birds and where 37 species were introduced but went extinct (failed invasions). We develop a modified approach to evaluate the effects of community saturation on invasion failure. Our method accounts (1) for the number of species present (NSP) when the species goes extinct rather than during its introduction; and (2) scaling patterns in bird body mass distributions that accounts for the hierarchical organization of ecosystems and the fact that interaction strength amongst species varies with scale. We found that when using NSP at the time of extinction, NSP was higher for failed introductions as compared to successful introductions, supporting the idea that increasing species richness and putative community saturation mediate invasion resistance. Accounting for scale-specific patterns in body size distributions further improved the relationship between NSP and introduction failure. Results show that a better understanding of invasion outcomes can be obtained when scale-specific community structure is accounted for in the analysis.

Hawaii↗

USGS2009

Thatcher Bay, Washington, Nearshore Restoration Assessment

The San Juan Archipelago, located at the confluence of the Puget Sound, the Straits of Juan de Fuca in Washington State, and the Straits of Georgia, British Columbia, Canada, provides essential nearshore habitat for diverse salmonid, forage fish, and bird populations. With 408 miles of coastline, the San Juan Islands provide a significant portion of the available nearshore habitat for the greater Puget Sound and are an essential part of the regional efforts to restore Puget Sound (Puget Sound Shared Strategy 2005). The nearshore areas of the San Juan Islands provide a critical link between the terrestrial and marine environments. For this reason the focus on restoration and conservation of nearshore habitat in the San Juan Islands is of paramount importance. Wood-waste was a common by-product of historical lumber-milling operations. To date, relatively little attention has been given to the impact of historical lumber-milling operations in the San Juan Archipelago. Thatcher Bay, on Blakely Island, located near the east edge of the archipelago, is presented here as a case study on the restoration potential for a wood-waste contaminated nearshore area. Case study components include (1) a brief discussion of the history of milling operations. (2) an estimate of the location and amount of the current distribution of wood-waste at the site, (3) a preliminary examination of the impacts of wood-waste on benthic flora and fauna at the site, and (4) the presentation of several restoration alternatives for the site. The history of milling activity in Thatcher Bay began in 1879 with the construction of a mill in the southeastern part of the bay. Milling activity continued for more than 60 years, until the mill closed in 1942. Currently, the primary evidence of the historical milling operations is the presence of approximately 5,000 yd3 of wood-waste contaminated sediments. The distribution and thickness of residual wood-waste at the site was determined by using sediment coring and GIS-based interpolation techniques. Additionally, pilot studies were conducted to characterize in place sediment redox, organic composition, and sulfide impacts to nearshore flora and fauna. We found that the presence of wood-waste in Thatcher Bay may alter the quality of the benthic habitat by contributing to elevated levels of total organic composition (TOC) of the sediment. Increased TOC favors anaerobic respiration in marine sediments, and sulfide, a toxic by-product of this process, was found at levels as high as 17.5 mg L-1 in Thatcher Bay. The Thatcher Bay sulfide levels are several orders of magnitude higher than those known to impact benthic invertebrates. Eelgrass, Zostera marina, located on the western margin of Thatcher Bay, was surveyed by using underwater video surveys. This baseline distribution will in part be used to measure the impact of any future remediation efforts. Additionally, the distribution and survey data can provide an estimate of propagule source for future colonization of restored sediment. Three restoration alternatives were considered, and a ranking matrix was developed to score each alternative against site-specific and regional criteria. The process identified the removal of wood-waste from a water-based platform as the preferred alternative. Our multidisciplinary investigation identified the location, thickness, and potential impacts of wood-waste that has persisted in the nearshore environment of Thatcher Bay since at least 1942. We also provide a process to efficiently evaluate alternatives to remediate the impact of this historical disturbance and to potentially contribute to an increase of nearshore diversity and productivity at this site. Elements of this approach could inform restoration planning at similarly impacted sites throughout the region.

Open-File Report↗

USGS2017

Examining fluvial fish range loss with SDMs

Fluvial fishes face increased imperilment from anthropogenic activities, but the specific factors contributing most to range declines are often poorly understood. For example, the range of the fluvial‐specialist shoal bass ( Micropterus cataractae ) continues to decrease, yet how perceived threats have contributed to range loss is largely unknown. We used species distribution models to determine which factors contributed most to shoal bass range loss. We estimated a potential distribution based on natural abiotic factors and a series of currently occupied distributions that incorporated variables characterizing land cover, non‐native species, and river fragmentation intensity (no fragmentation, dams only, and dams and large impoundments). We allowed interspecific relationships between non‐native congeners and shoal bass to vary across fragmentation intensities. Results from the potential distribution model estimated shoal bass presence throughout much of their native basin, whereas models of currently occupied distribution showed that range loss increased as fragmentation intensified. Response curves from models of currently occupied distribution indicated a potential interaction between fragmentation intensity and the relationship between shoal bass and non‐native congeners, wherein non‐natives may be favored at the highest fragmentation intensity. Response curves also suggested that >100 km of interconnected, free‐flowing stream fragments were necessary to support shoal bass presence. Model evaluation, including an independent validation, suggested that models had favorable predictive and discriminative abilities. Similar approaches that use readily available, diverse, geospatial data sets may deliver insights into the biology and conservation needs of other fluvial species facing similar threats.

Conservation Biology↗

USGS1979

Hydrologic data on channel adjustments, 1970 to 1975, on the Rio Grande downstream from Cochiti Dam, New Mexico before and after closure

Cross-section channel profiles, sediment transport and hydrologic data have been observed (before and after closure of the dam) and computed for a series of investigations from 1970 to 1975 at 37 cross sections established along a 59 mile (95 kilometer) study reach from Cochiti Dam to Isleta Diversion Dam, N. Mex. Cochiti Dam began impounding water in November 1973. Because the dam will trap virtually all of the sediment load originating upstream and water discharge will be controlled, it is expected that equilibrium values of channel width, depth, slope and sediment-transport capability in the existing main stem of the Rio Grande will change. Changes in cross sections with time and space and changes in size distribution of sediments are documented.

New Mexico↗

USGS2007

Grassland and shrubland birds of Gettysburg National Military Park and Eisenhower National Historic Site: Current status and management recommendations

Gettysburg National Military Park (NMP) and Eisenhower National Historic Site (NHS) were surveyed for grassland birds during the 2005 breeding season. These parks currently maintain a total of approximately 1,220 ha (3,015 ac) of grassland habitats within a mosaic of cultivated fields and woodlands. The grasslands are hayfields managed through agricultural leases and fields maintained by the National Park Service (NPS). Most grasslands are composed of introduced cool-season grasses, but Gettysburg NMP maintains a few fields dominated by switchgrass (Panicum virgatum) and is creating additional warm-season grasslands. Hayfields managed through agricultural leases support few grassland birds. The most numerous grassland bird communities are found between Seminary and Cemetery ridges in fields managed by the NPS. The parks discourage hay harvesting before July in all fields in an effort to improve the reproductive success of grassland birds. Shrub-dominated habitats were scarce in both parks. A few areas that were harvested recently for timber supported early successional communities in Gettysburg NMP. Other shrublands were limited to narrow corridors (<10 m [32 ft]) bordering fields and drainages. No shrublands were present on Eisenhower NHS, but an abandoned pasture along Willoughby Run was reverting into a mesic shrubland. Four species of obligate grassland birds were recorded during the 2005 surveys. A population of approximately 130 bobolinks (Dolichonyx oryzivorus) was primarily restricted to grasslands between Seminary and Cemetery ridges maintained by the NPS and a hayfield on Eisenhower NHS. This population is large for southeastern Pennsylvania and the surrounding region. Eastern meadowlarks (Sturnella magna) were most numerous in the same fields occupied by bobolinks but smaller numbers were scattered in other grasslands. Grasshopper sparrows (Ammodramus savannarum) were locally distributed in Conservation Reserve Program fields and other grasslands with more open vegetation. Savannah sparrows (Passervulus sandwichensis) were limited to one disturbed area undergoing conversion to warm-season grasses. When compared with other cultural parks in this region, the Gettysburg-Eisenhower complex supports a relatively abundant grassland bird community. This community is restricted to a portion of existing grassland habitats, but the potential exists to support a more diverse and abundant grassland avifauna. The following recommendations provide the most immediate benefits for breeding grassland birds in these parks under the current habitat conditions and management strategies. These recommendations are based on the assumption that the current policy of delayed mowing continues in both parks: improve grassland composition on leased hayfields; increase extent of early successional stages of grasslands; reduce fragmentation of grassland habitats; and improve grassland diversity by creating additional communities of native warm-season grasses. Because shrublands are currently scarce in both parks, the only recommendation is directed towards creating and maintaining shrub-dominated successional habitats: Explore opportunities for creating shrubby successional habitats in both parks.

Technical Report↗

USGS2006

Vascular Plant and Vertebrate Inventory of Casa Grande Ruins National Monument

Executive Summary This report summarizes results of the first comprehensive biological inventory of Casa Grande Ruins National Monument (NM) in southern Arizona. Surveys at the monument were part of a larger effort to inventory vascular plants and vertebrates in eight National Park Service units in Arizona and New Mexico. In 2001 and 2002 we surveyed for vascular plants and vertebrates (amphibians, reptiles, birds, and mammals) at Casa Grande Ruins NM to document the presence, and in some cases relative abundance, of species. By using repeatable study designs and standardized field techniques, which included quantified survey effort, we produced inventories that can serve as the basis for a biological monitoring program. Of the National Park Service units in the region, no other has experienced as much recent ecological change as Casa Grande Ruins NM. Once situated in a large and biologically diverse mesquite bosque near the perennially flowing Gila River, the monument is now a patch of sparse desert vegetation surrounded by urban and commercial development that is rapidly replacing agriculture as the dominant land use in the area. Roads, highways, and canals surround the monument. Development, and its associated impacts, has important implications for the plants and animals that live in the monument. The plant species list is small and the distribution and number of non-native plants appears to be increasing. Terrestrial vertebrates are also being impacted by the changing landscape, which is increasing the isolation of these populations from nearby natural areas and thereby reducing the number of species at the monument. These observations are alarming and are based on our review of previous studies, our research in the monument, and our knowledge of the biogeography and ecology of the Sonoran Desert. Together, these data suggest that the monument has lost a significant portion of its historic complement of species and these changes will likely intensify as urbanization continues. Despite isolation of the monument from nearby natural areas, we recorded noteworthy species or observations for all taxonomic groups: * Plants: night-blooming cereus * Amphibians: high abundance of Couch's spadefoot toads * Reptiles: high abundance of long-nosed snakes * Birds: 10 species of diurnal raptors including 4 species of falcons * Mammals: American badger This study is a first step in the process of compiling information about the biological resources of Casa Grande Ruins NM and surrounding areas. We recommend additional inventory and research studies, and we identify aspects of our effort that could be improved upon through application of new techniques or by extending the temporal (and possibly spatial) scope of our work.

Open-File Report↗

USGS2011

Carbonatite and alkaline intrusion-related rare earth element deposits–A deposit model

The rare earth elements are not as rare in nature as their name implies, but economic deposits with these elements are not common and few deposits have been large producers. In the past 25 years, demand for rare earth elements has increased dramatically because of their wide and diverse use in high-technology applications. Yet, presently the global production and supply of rare earth elements come from only a few sources. China produces more than 95 percent of the world's supply of rare earth elements. Because of China's decision to restrict exports of these elements, the price of rare earth elements has increased and industrial countries are concerned about supply shortages. As a result, understanding the distribution and origin of rare earth elements deposits, and identifying and quantifying our nation's rare earth elements resources have become priorities. Carbonatite and alkaline intrusive complexes, as well as their weathering products, are the primary sources of rare earth elements. The general mineral deposit model summarized here is part of an effort by the U.S. Geological Survey's Mineral Resources Program to update existing models and develop new descriptive mineral deposit models to supplement previously published models for use in mineral-resource and mineral-environmental assessments. Carbonatite and alkaline intrusion-related REE deposits are discussed together because of their spatial association, common enrichment in incompatible elements, and similarities in genesis. A wide variety of commodities have been exploited from carbonatites and alkaline igneous rocks, such as rare earth elements, niobium, phosphate, titanium, vermiculite, barite, fluorite, copper, calcite, and zirconium. Other enrichments include manganese, strontium, tantalum, thorium, vanadium, and uranium.

Open-File Report↗

USGS2013

Survey of bats on Columbia National Wildlife Refuge, Washington, December 2011-April 2012

Bats are diverse and abundant in many ecosystems worldwide. They perform important ecosystem functions, particularly by consuming large quantities of insects (Cleveland and others, 2006; Jones and others, 2009; Kuhn and others, 2011). The importance of bats to biodiversity and to ecosystem integrity has been overlooked in many regions, largely because the challenges of detecting and studying these small, nocturnal mammals have rendered a paucity of information on matters as basic as species distribution and natural history attributes. Recently, concern for bats has arisen in response to recognition of large-scale threats, such as white-nosed syndrome (WNS; Turner and others, 2009; Frick and others, 2010) and mortality at wind energy facilities (Arnett and others, 2008), factors that are causing unprecedented population declines of bats (Boyles and others, 2011). WNS is a fungal disease that has killed more than 1 million cave-hibernating bats in eastern North America since being discovered in New York State in 2006 (U.S. Fish and Wildlife Service, 2012). WNS has spread rapidly from northeastern U.S., and as of August 2012 has been confirmed as far west as eastern Missouri(U.S. Fish and Wildlife Service, 2013). Given the rapid spread of WNS, there is concern that the disease may soon affect western bat populations. Hibernating bats are particularly vulnerable to the effects of WNS (Blehert and others, 2009). Refuges in eastern Washington, including the Mid-Columbia River National Wildlife Refuge Complex (MCRNWRC) and Little Pend Oreille National Wildlife Refuge, support many potential hibernacula. Sixteen species of bats potentially occur on these refuges, including one federally listed species of concern (Townsend’s big-eared bat [Corynorhinus townsendii]; see table 1 for scientific names of bats), and 12 species that are of conservation concern in Washington and Oregon (table 1). However, little is known about bats on these refuges because few surveys have been done, and none have been done during winter. Refuge biologists are lacking even the most basic information, such as species presence, and location and status of hibernacula. In order to assess vulnerability and develop a strategy for management of WNS, refuge managers need to know where bats are hibernating, and which species are using each hibernaculum. The goal of this project was to provide information on the status of wintering bats to refuge biologists and managers in order to support decision-making that might minimize the threat of WNS in western bat populations. We conducted surveys of bat activity in winter and early spring as an initial step toward identifying bat species that may be over-wintering and locating potential hibernacula on these refuges. Our specific objectives were to identify bat species using the refuges, to identify areas of resident bat activity in autumn, winter, and early spring using acoustic bat detectors, and to try new methods for quick surveys of bat activity.

Oregon;Washington↗

USGS2012

Sediment loads in the Red River of the North and selected tributaries near Fargo, North Dakota, 2010--2011

Natural-resource agencies are concerned about possible geomorphic effects of a proposed diversion project to reduce the flood risk in the Fargo-Moorhead metropolitan area. The U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers collected data in the spring of 2010 and 2011, and from June to November 2011, during rainfall-runoff events and base-flow conditions to provide information on sediment transport. The data were used to examine sediment concentrations, loads, and particle-size distributions at nine selected sites in the Red River and its tributaries near the Fargo-Moorhead metropolitan area. Suspended-sediment concentration varied among sites in 2010 and 2011. The least suspended-sediment concentrations were measured at the Red River (site 1) and the Buffalo River (site 9), and the greatest concentrations were measured at the two Sheyenne River sites (sites 3 and 4). Estimated daily suspended-sediment loads were highly variable in 2010 and 2011 in the Red River and its tributaries, with the greatest loads occurring in the spring and the smallest loads occurring in the winter. For the Red River, daily suspended-sediment loads ranged from 26 to 3,500 tons per day at site 1 and from 30 to 9,010 tons per day at site 2. For the Sheyenne River, daily loads ranged from less than 10 to 10,200 tons per day at site 3 and from less than 10 to 4,530 tons per day at site 4. The mean daily load was 191 tons per day in 2010 and 377 tons per day in 2011 for the Maple River, and 610 tons per day in 2011 for the Wild Rice River (annual loads were not computed for 2010). For the three sites that were only sampled in 2011 (sites 7, 8 and 9), the mean daily suspended-sediment loads ranged from 40 tons per day at the Lower Branch Rush River (site 8) to 118 tons per day at the Buffalo River (site 9). For sites that had estimated loads in 2010 and 2011 (sites 1–5), estimated annual (March–November) suspended-sediment loads were greater in 2011 compared to 2010. In 2010, annual loads ranged from 68,650 tons per year at the Maple River (site 5) to 249,040 tons per year at the Sheyenne River (site 3). In 2011, when all nine sites were sampled, annual loads ranged from 8,716 tons per year at the Lower Branch Rush River (site 8) to 552,832 tons per year at the Sheyenne River (site 3). With the exception of the Sheyenne River (site 4), the greatest monthly loads occurred in March for 2010, with as little as 27 percent (site 1) and as much as 42 percent (site 3) of the annual load occurring in March. For 2011, the greatest monthly loads occurred in April, ranging from 33 percent (site 1) to 63 percent (site 7) of the 2011 annual load. A relatively small amount of sediment was transported past the nine sites as bedload in 2010 and 2011. For most of the samples collected at the nine sites, the bedload composed less than 1 percent of the calculated daily total sediment load.

North Dakota↗