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At least 865 records · Page 48Linked to original sources
USGS2025

Canopy and surface fuels measurement using terrestrial lidar single-scan approach in the Mogollon highlands of Arizona

Background Fuel monitoring data are essential to evaluate wildfire risk, plan management activities and evaluate fuel treatment effects. Terrestrial light detection and ranging (lidar) is a field-based 3D scanning technology with great potential to reduce labor-intensive field measurements and provide new depths of vegetation structure data. Aims To facilitate the integration of terrestrial lidar into fuel monitoring programs, we developed a model, training process, and Python program that produces canopy fuel, surface fuel and terrain metrics commonly used in fire behavior and fire risk modeling. Methods We estimated canopy and surface fuel metrics from terrestrial lidar using a semi-empirical model incorporating physically based modeling of leaf area density and occlusion and a non-destructive model calibration process leveraging Bayesian regression. We compared lidar-derived fuel estimates with conventional fuel estimates across diverse conditions in semi-arid shrubland, woodland and forest in Arizona. We also compared estimates using single- and multiple-scan modes. Key results In single-scan mode, our lidar-derived fuel estimates were significantly related to conventional estimates of total canopy fuel load, maximum canopy bulk density, downed surface fuel load and standing surface fuel load. Implications Our methods provide opportunities to increase the scalability of fuel monitoring to better understand wildfire risk and treatment effectiveness.

Arizona↗
USGS2010

Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: NLCD 2001 Imperviousness

This data set represents the mean percent impervious surface from the Imperviousness Layer of the National Land Cover Dataset 2001 (LaMotte and Wieczorek, 2010), compiled for every catchment of NHDPlus for the conterminous United States. The source data set represents imperviousness for the conterminous United States for 2001. The Imperviousness Layer of the National Land Cover Data Set for 2001 was produced through a cooperative project conducted by the Multi-Resolution Land Characteristics (MRLC) Consortium. The MRLC Consortium is a partnership of Federal agencies (http://www.mrlc.gov), consisting of the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), the U.S. Environmental Protection Agency (USEPA), the U.S. Department of Agriculture (USDA), the U.S. Forest Service (USFS), the National Park Service (NPS), the U.S. Fish and Wildlife Service (USFWS), the Bureau of Land Management (BLM), and the USDA Natural Resources Conservation Service (NRCS). The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, contains NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the Missouri River basins, contains NHDPlus Production Units 10-lower and 10-upper. MRB5, covering the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins, contains NHDPlus Production Units 8, 11 and 12. MRB6, covering the Rio Grande, Colorado and Great Basin River basins, contains NHDPlus Production Units 13, 14, 15 and 16. MRB7, covering the Pacific Northwest River basins, contains NHDPlus Production Unit 17. MRB8, covering California River basins, contains NHDPlus Production Unit 18.

Data Series↗
USGS2010

Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: NLCD 2001 Land Use and Land Cover

This data set represents the estimated area of land use and land cover from the National Land Cover Dataset 2001 (LaMotte, 2008), compiled for every catchment of NHDPlus for the conterminous United States. The source data set represents land use and land cover for the conterminous United States for 2001. The National Land Cover Data Set for 2001 was produced through a cooperative project conducted by the Multi-Resolution Land Characteristics (MRLC) Consortium. The MRLC Consortium is a partnership of Federal agencies (http://www.mrlc.gov), consisting of the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), the U.S. Environmental Protection Agency (USEPA), the U.S. Department of Agriculture (USDA), the U.S. Forest Service (USFS), the National Park Service (NPS), the U.S. Fish and Wildlife Service (USFWS), the Bureau of Land Management (BLM), and the USDA Natural Resources Conservation Service (NRCS). The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, contains NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the Missouri River basins, contains NHDPlus Production Units 10-lower and 10-upper. MRB5, covering the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins, contains NHDPlus Production Units 8, 11 and 12. MRB6, covering the Rio Grande, Colorado and Great Basin River basins, contains NHDPlus Production Units 13, 14, 15 and 16. MRB7, covering the Pacific Northwest River basins, contains NHDPlus Production Unit 17. MRB8, covering California River basins, contains NHDPlus Production Unit 18.

Data Series↗
USGS1995

USGS supports ecosystem management in the San Francisco bay and delta

In the past several years, the Department of the Interior has ,l?laced particular emphasis on "ecosystem management" - the integration of scientific knowledge of ecological relationships with resource management practices to sustain ecological, cultural, and economic systems in broad habitat areas; eg., forest, desert, and aquatic habitats. The goal of ecosystem management is to understand the habitat requirements of many species and thereby assess the impact of a variety of human activities on regional biodiversity rather than to manage for individual species. In support of the management of the natural resources of San Francisco Bay and the delta, the USGS is augmenting its ongoing research program to provide additional research, monitoring, and assessment information and to improve the availability of that information. Following a workshop with resource and regulatory agency representatives, hosted by the USGS in early 1994, USGS researchers identified specific areas where existing and new scientific information could contribute to resolving some of the critical bay and delta land and aquatic management issues. The "ecosystems initiative" effort now underway addresses questions in three areas: Freshwater flow, including sediment and contaminant transport. Wetlands. Information and data access. Following is a brief description of activities being supported by this initiative.

Interagency Ecological Program Newsletter↗
USGS2015

Landscape characteristics influencing the genetic structure of greater sage-grouse within the stronghold of their range: a holistic modeling approach

Given the significance of animal dispersal to population dynamics and geographic variability, understanding how dispersal is impacted by landscape patterns has major ecological and conservation importance. Speaking to the importance of dispersal, the use of linear mixed models to compare genetic differentiation with pairwise resistance derived from landscape resistance surfaces has presented new opportunities to disentangle the menagerie of factors behind effective dispersal across a given landscape. Here, we combine these approaches with novel resistance surface parameterization to determine how the distribution of high- and low-quality seasonal habitat and individual landscape components shape patterns of gene flow for the greater sage-grouse ( Centrocercus urophasianus ) across Wyoming. We found that pairwise resistance derived from the distribution of low-quality nesting and winter, but not summer, seasonal habitat had the strongest correlation with genetic differentiation. Although the patterns were not as strong as with habitat distribution, multivariate models with sagebrush cover and landscape ruggedness or forest cover and ruggedness similarly had a much stronger fit with genetic differentiation than an undifferentiated landscape. In most cases, landscape resistance surfaces transformed with 17.33-km-diameter moving windows were preferred, suggesting small-scale differences in habitat were unimportant at this large spatial extent. Despite the emergence of these overall patterns, there were differences in the selection of top models depending on the model selection criteria, suggesting research into the most appropriate criteria for landscape genetics is required. Overall, our results highlight the importance of differences in seasonal habitat preferences to patterns of gene flow and suggest the combination of habitat suitability modeling and linear mixed models with our resistance parameterization is a powerful approach to discerning the effects of landscape on gene flow.

Ecology and Evolution↗
USGS2024

Mapping riparian vegetation response to climate change on the San Carlos Apache Reservation and Upper Gila River watershed to inform restoration priorities: 1935 to Present

The riparian vegetation within the San Carlos Apache Reservation (hereafter Reservation), within the Upper Gila River watershed extending from southwestern New Mexico into southeastern Arizona, provides immense ecological and cultural value to the people of the San Carlos Apache Tribe (hereafter referred to as the Tribe/Tribal) but has experienced substantial changes and stresses over the past century because of fluctuations in climate and a series of human-induced and natural disturbances. This research addresses these challenges by analyzing the riparian vegetation within the Upper Gila River watershed using aerial and satellite imagery, and by documenting the direct relationship to fluctuations in climate conditions. Results from this study would be provided to the Tribe to help the Tribe develop a restoration plan for their riparian forests. We show that the riparian vegetation has largely increased overall in greenness throughout the study period (i.e., 1985 through 2021), despite periods of drought conditions. This extends to the end of our study period particularly with native vegetation in the upper watershed. However, non-native and invasive tamarisk vegetation within much of the lower watershed has shown declining trends and increasing vegetative stress. Furthermore, these areas have experienced a large increase in wildfire presence and other disturbances. Nevertheless, Tribal restoration applications have been shown to increase native vegetation plant cover, suggesting that restoration activities have been successful overall.

Arizona, New Mexico↗
USGS2017

Revised age of deglaciation of Lake Emma based on new radiocarbon and macrofossil analyses

Previous radiocarbon ages of detrital moss fragments in basal organic sediments of Lake Emma indicated that extensive deglaciation of the San Juan Mountains occurred prior to 14,900 yr B.P. (Carrara et al., 1984). Paleoecological analyses of insect and plant macrofossils from these basal sediments cast doubt on the reliability of the radiocarbon ages. Subsequent accelerator radiocarbon dates of insect fossils and wood fragments indicate an early Holocene age, rather than a late Pleistocene age, for the basal sediments of Lake Emma. These new radiocarbon ages suggest that by at least 10,000 yr B.P. deglaciation of the San Juan Mountains was complete. The insect and plant macrofossils from the basal organic sediments indicate a higher-than-present treeline during the early Holocene. The insect assemblages consisted of about 30% bark beetles, which contrasts markedly with the composition of insects from modern lake sediments and modern specimens collected in the Lake Emma cirque, in which bark beetles comprise only about 3% of the assemblages. In addition, in the fossil assemblages there were a number of flightless insect species (not subject to upslope transport by wind) indicative of coniferous forest environments. These insects were likewise absent in the modern assemblage. ?? 1991.

Quaternary Research↗
USGS2015

Geological processes and orchid biogeography with applications to southeast central America

This contribution owes its origins to a paper presentation by Dr. Calloway H. Dodson at the Second International Conference on Neotropical Orchidology held in San José, Costa Rica in May of2003 (Dodson 2003). Dr. Dodson outlined some ofthe reasons to suspect that regional geological fac-tors may play important roles in orchid speciation and biogeography and gave examples from the northwestern South America. He also suggested that evolutionary change in orchid might occur over fairly short time periods, perhaps even as short as decades, centuries or millennia (Dodson 2003, SHK lecture notes). These ideas stimulated the author, a professional earth scientist, to begin thinking about how these exciting ideas could begin to be tested in Costa Rica neighboring and Central American countries, an area that has drawn him to return frequently over the last decade. The present contribution is a proposal for integrating geological observations, such as the chronology of arc volcanic activity in Nicaragua,Costa Rica, and Panama, in hypothesis forming and testing of the geographic distribution of orchids (and possibly other biota). I initially focus on comparisons between orchid inventories on the windward slopes of mountainous regions (elevation > 1000 m)with high rainfall (> 1-2 m) in tropical regions, the so-called tropical cloud forests. These regions represent the tropical pre-montane rain forestto lower montane tropical rain forest life zones of Holdridge(1967) and the montane vegetation zone applied to Costa Rica and Panama by Dressler (1993). An important message of this paper is that such tropical mountainous regions are not necessarily static, but may change in elevation over geologic time due to active tectonic deformation and uplift and that the presence of active volcanism in a mountain range may also introduce additional chemical factors, such as volcanic gases, acid rain, and volcanic soils, and also physical factors, such as interruption of gene flow by explosive eruptions and coverage by their air fall products such as ash (tephra), lava flows, and lahars (volcanic mudflows). Thus over a given geological time interval, forests may be slowly increasing in elevation by tectonic uplift or by the accumulation of volcanic products such as steep-sided strato volcanoes (built from both lavas and tephra), or by down-slope accumulations of lava flows or lahars. Mountains may also lose elevation by erosion or by tectonic subsidence. As we shall see, tropical Central America shows an extraordinarily high level of tectonic and volcanic history that has changed its geography and, by implication, climate, life zones,and likely orchid distribution. My working hypo thesis put forward for testing is that orchid adaptations to these changes may have led to the development of new species and endemism in this region.

Lankesteriana↗
USGS2005

Public access management as an adaptive wildlife management tool

Wildlife populations across the United States are benefiting from improved wildlife management techniques. However, these benefits also create new challenges including overpopulation, disease, increased winter kill, and forage degradation. These issues have become the challenges for natural resource managers and landowners. Specifically, elk (Cervus elaphus) populations in the Gunnison River Valley of Colorado are growing and causing increased resource damage on public and private lands. On public lands elk threaten sage grouse habitat and compete with domestic livestock for available forage; on private lands they diminish available livestock forage. Management of elk and elk habitat in this area is a shared responsibility of the NPS (Black Canyon of the Gunnison National Park and Curecanti National Recreation Area), BLM (Uncompahgre Field Office), USFS (Gunnison National Forest), and the CDOW (Colorado Division of Wildlife). All of these agencies participate in this research and adaptive management project. One key issue in the Black Mesa – Black Canyon area is the interaction between motorized vehicles and. The working hypothesis for this study is that early season elk movement onto private lands and the National Park is precipitated by increased use of Off Highway Vehicles (OHV’s). Data on intensity of motorized use is extremely limited. In this study, we monitor intensity of motorized vehicle and trail use on elk movements and habitat usage and analyze interactions. If management agencies decide to alter accessibility, we will monitor wildlife responses to changes in the human-use regime. This provides a unique opportunity for adaptive management experimentation based on coordinated research and monitoring. The products from this project will provide natural resource managers across the nation with tools and information to better meet these resource challenges.

Open-File Report↗
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↗
USGS2008

Questa baseline and pre-mining ground-water quality investigation. 17. Geomorphology of the Red River Valley, Taos County, New Mexico, and influence on ground-water flow in the shallow alluvial aquifer

In April 2001, the U.S. Geological Survey (USGS) and the New Mexico Environment Department (NMED) began a cooperative study to infer the pre-mining ground-water chemistry at the Molycorp molybdenum mine site in the Red River Valley of north-central New Mexico. This report is one in a series of reports that can be used to determine pre-mining ground-water conditions at the mine site. Molycorp’s Questa molybdenum mine in the Red River Valley, northern New Mexico, is located near the margin of the Questa caldera in a highly mineralized region. The bedrock of the Taos Range surrounding the Red River is composed of Proterozoic rocks of various types, which are intruded and overlain by Oligocene volcanic rocks associated with the Questa caldera. Locally, these rocks were altered by hydrothermal activity. The alteration zones that contain sulfide minerals are particularly important because they constitute the commercial ore bodies of the region and, where exposed to weathering, form sites of rapid erosion referred to as alteration scars. Over the past thousand years, if not over the entire Holocene, erosion rates were spatially variable. Forested hillslopes eroded at about 0.04 millimeter per year, whereas alteration scars eroded at about 2.7 millimeters per year. The erosion rate of the alteration scars is unusually rapid for naturally occurring sites that have not been disturbed by humans. Watersheds containing large alteration scars delivered more sediment to the Red River Valley than the Red River could remove. Consequently, large debris fans, as much as 80 meters thick, developed within the valley. The geomorphology of the Red River Valley has had several large influences on the hydrology of the shallow alluvial aquifer, and those influences were in effect before the onset of mining within the watershed. Several reaches where alluvial ground water emerges to become Red River streamflow were observed by a tracer dilution study conducted in 2001. The aquifer narrows where erosion-resistant bedrock, which tends to form vertical cliffs, restricts the width of the valley bottom. Although the presence of a shallow bedrock sill, overlain by shallow alluvium, is a plausible cause of ground-water emergence, this cause was not demonstrated in the study area. The water-table gradient can locally decrease in the downstream direction because of changes in the hydraulic properties of the alluvium, and this may be a contributing cause of ground-water emergence. However, at one site (near Cabin Springs), ground-water emergence could not be explained by spatial changes in geometric or hydraulic properties of the aquifer. Furthermore, the available evidence demonstrates that ground water flowing through bedrock fractures or colluvium entered the north side of the alluvial aquifer, and is the cause of ground-water emergence. At that location the alluvial aquifer was already flowing full, causing the excess water to emerge into the stream. An indirect consequence of altered rock in the tributary watersheds is the rapid erosion rate of alteration scars combined with the hydraulic properties of sediments shed from those scars. Where alteration scars are large the debris fans at the mouths of the tributary watersheds substantially encroach into the Red River Valley. At such locations debris-fan materials dominate the width and thickness of the alluvium in the valley and reduce the rate of flow of ground water within the Red River alluvial aquifer. Most sites of groundwater emergence are located immediately upstream from or along the margins of debris fans. A substantial fraction of the ground water approaching a debris fan can emerge to become streamflow. This last observation has three implications. First, very little water can flow the entire length of the study area entirely within the alluvial aquifer because the ground water repeatedly contacts debris-fan sediments over that length. Second, it follows that emerging water containing unique elemental constituents must have entered the alluvial aquifer at a relatively short distance upstream. Third, a gravel aquifer downstream from a large debris fan can transmit more ground water than flows into it through the debris fan. This observation explains how the water table can be naturally, and permanently, located well beneath the level of the bed of a perennial stream.

New Mexico↗
USGS2022

Application of a soil-water-balance model to estimate annual groundwater recharge for Long Island, New York, 1900–2019

A soil-water-balance (SWB) model was developed for Long Island, New York, to estimate the potential amount of annual groundwater recharge to the Long Island aquifer system from 1900 to 2019. The SWB model program is a computer code based on a modified Thornthwaite-Mather SWB approach and uses spatially and temporally distributed meteorological, land-cover, and soil properties as input to compute potential daily groundwater recharge. Simulated outputs indicate that island-wide potential groundwater recharge trends, as a percentage of precipitation, have increased approximately 3 percent during the 120-year period. The simulated results account for both climatic and land-cover changes that have occurred during the period. A change from undeveloped (forested land cover) to low- and medium-density residential land cover or land use increased potential groundwater recharge because of a decrease in evapotranspiration. During the 30-year period from 1900 to 1930, the simulated potential average groundwater recharge rate on Long Island was estimated to be 18.50 inches per year (in/yr), or a total of 1,243 million gallons per day, during the 30-year period from 1985 to 2015, the simulated potential average groundwater recharge rate estimate increased to 20.73 in/yr (a total of around 1,393 million gallons per day). During the 1900–2019 simulation period, the potential average annual groundwater recharge rate was about 19.24 in/yr. The data for that period included values for a 3-year meteorological drought from 1963 to 1965, where the mean precipitation was about 26.5 percent lower than the long-term average of 46.7 in/yr, and the potential groundwater recharge rate was about 12.3 in/yr. During a 3-year wet period from 1982 to 1984, where mean precipitation was about 19.6 percent higher than the long-term average, the estimated potential groundwater recharge rate was about 26.8 in/yr.

New York↗
USGS2017

Evaluation of the streamgage network for estimating streamflow statistics at ungaged sites in Pennsylvania and the Susquehanna River Basin in Pennsylvania and New York

The current (2015) streamgage network in Pennsylvania and the Susquehanna River Basin in Pennsylvania and New York was evaluated in order to design a network that would meet the hydrologic needs of many partners and serve a variety of purposes and interests, including estimation of streamflow statistics at ungaged sites. This study was done by the U.S. Geological Survey, in cooperation with the Pennsylvania Department of Environmental Protection and the Susquehanna River Basin Commission. The study area includes the Commonwealth of Pennsylvania and the Susquehanna River Basin in Pennsylvania and New York. For this study, 229 streamgages were identified as reference streamgages that could be used to represent ungaged watersheds. Criteria for a reference streamgage are a minimum of 10 years of continuous record, minimally altered streamflow, and a drainage area less than 1,500 square miles. Some of the reference streamgages have been discontinued but provide historical hydrologic information valuable in the determination of streamflow characteristics of ungaged watersheds. Watersheds in the study area not adequately represented by a reference streamgage were identified by examining a range of basin characteristics, the extent of geographic coverage, and the strength of estimated streamflow correlations between gaged and ungaged sites. Basin characteristics were determined for the reference streamgage watersheds and the 1,662 12-digit hydrologic unit code (HUC12) subwatersheds in Pennsylvania and the Susquehanna River Basin using a geographic information system (GIS) spatial analysis and nationally available GIS datasets. Basin characteristics selected for this study include drainage area, mean basin elevation, mean basin slope, percentage of urbanized area, percentage of forested area, percentage of carbonate bedrock, mean annual precipitation, and soil thickness. A GIS spatial analysis was used to identify HUC12 subwatersheds outside the range of basin characteristics of the reference streamgages. There were 320 HUC12 subwatersheds, or 19 percent of the study area, with basin characteristics outside the range represented by the reference streamgage watersheds. A GIS spatial analysis was used to identify geographic gaps in the streamgage network. For each streamgage, a watershed area, called the gage statistical area (GSA), was delineated. The GSA shows the drainage area within a specific drainage-area ratio of the streamgage for transfer of streamflow statistics from that streamgage to ungaged sites on the valid statistical reach of the GSA for a streamgage. In Pennsylvania, a drainage-area ratio of 0.33–3 times the drainage area of the ungaged site was found to perform as well as, if not better than, more traditional ratios such as 0.5–1.5 (or 2) for transfer of selected streamflow statistics. A total of 1,102 HUC12 subwatersheds, or 66 percent of the study area, are outside the GSA for a reference streamgage. The USGS Baseline Streamflow Estimator (BaSE) program was used to determine how well HUC12 subwatersheds outside the streamgage GSAs are represented by the reference streamgage network in Pennsylvania, based on estimated streamflow correlation. The centroid of each HUC12 subwatershed was run through the BaSE program to determine the reference streamgage with the highest estimated streamflow correlation. There were 929 HUC12 subwatersheds in Pennsylvania, or 56 percent of the State, with an estimated correlation coefficient less than 0.96. The results from the basin characteristic, geographic, and streamflow correlation analyses were combined to identify 1,405 HUC12 subwatersheds in Pennsylvania and the Susquehanna River Basin in Pennsylvania and New York that lack a representative reference, based on at least one identified gap. Of the 1,405 HUC12 subwatersheds, 139 exhibited all three gaps, indicating a 8-percent gap in the reference streamgage network. Streamgages in areas with similar hydrologic characteristics and in close proximity to one another can potentially provide similar information (termed streamgages with high substitution potential). Streamgages were considered to have a high substitution potential with a nearby streamgage(s) if (1) the streamflow correlation coefficient was equal to or greater than 0.96, (2) the streamgages had 10 years of concurrent record, and (3) the streamgages are in the same watershed within the GSA of the streamgage. Seventy-four current (2015) streamgages with high substitution potential with at least one other streamgage were identified in the study area. Although these identified streamgages have a high substitution potential, they provide valuable streamflow information to a stakeholder. Selected primary uses of these streamgages were identified to determine the overall need for an individual streamgage.

New York, Pennsylvania↗
USGS2015

Habitat influences distribution of chronic wasting disease in white-tailed deer

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy that was first detected in 1967 in a captive research facility in Colorado. In the northeastern United States, CWD was first confirmed in white-tailed deer ( Odocoileus virginianus ) in 2005. Because CWD is a new and emerging disease with a spatial distribution that had yet to be assessed in the Northeast, we examined demographic, environmental, and spatial effects to determine how each related to this spatial distribution. The objectives of our study were to identify environmental and spatial effects that best described the spatial distribution of CWD in free-ranging white-tailed deer and identify areas that support deer that are at risk for CWD infection in the Northeast. We used Bayesian hierarchical modeling that incorporated demographic covariates, such as sex and age, along with environmental covariates, which included elevation, slope, riparian corridor, percent clay, and 3 landscapes (i.e., developed, forested, open). The model with the most support contained landscape covariates and spatial effects that represented clustering of CWD in adjacent grid cells. Forested landscapes had the strongest relationship with the distribution of CWD, with increased risk of CWD occurring in areas that had lesser amounts of forest. Our results will assist resource managers in understanding the spatial distribution of CWD within the study area, and in surrounding areas where CWD has yet to be found. Efficiency of disease surveillance and containment efforts can be improved by allocating resources used for surveillance in areas with deer populations that are at greatest risk for infection.

Journal of Wildlife Management↗
USGS2011

Chemical ecology of red mangroves, Rhizophora mangle, in the Hawaiian Islands

The coastal red mangrove, Rhizophora mangle L., was introduced to the Hawaiian Islands from Florida 100 yr ago and has spread to cover many shallow intertidal shorelines that once were unvegetated mudflats. We used a field survey approach to test whether mangroves at the land-ocean interface could indicate watershed inputs, especially whether measurements of leaf chemistry could identify coasts with high nutrient inputs and high mangrove productivities. During 2001-2002, we sampled mangroves on dry leeward coasts of southern Moloka'i and O'ahu for 14 leaf variables including stable carbon and nitrogen isotopes (delta 13 C, delta 15 N), macronutrients (C, N, P), trace elements (B, Mn, Fe, Cu, Zn), and cations (Na, Mg, K, Ca). A new modeling approach using leaf Na, N, P, and delta 13 C indicated two times higher productivity for mangroves in urban versus rural settings, with rural mangroves more limited by low N and P nutrients and high-nutrient urban mangroves more limited by freshwater inputs and salt stress. Leaf chemistry also helped identify other aspects of mangrove dynamics: especially leaf delta 15 N values helped identify groundwater N inputs, and a combination of strongly correlated variables (C, N, P, B, Cu, Mg, K, Ca) tracked the mangrove growth response to nutrient loading. Overall, the chemical marker approach is an efficient way to survey watershed forcing of mangrove forest dynamics.

Hawai'i↗
USGS2011

Changes in monoterpene mixing ratios during summer storms in rural New Hampshire (USA)

Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA). Emitted from vegetation, monoterpenes are a product of photosynthesis and act as a response to a variety of environmental factors. Most parameterizations of monoterpene emissions are based on clear weather models that do not take into account episodic conditions that can drastically change production and release rates into the atmosphere. Here, the monoterpene dataset from the rural Thompson Farm measurement site in Durham, New Hampshire is examined in the context of a set of known severe storm events. While some storm systems had a negligible influence on ambient monoterpene mixing ratios, the average storm event increased mixing ratios by 0.59 ± 0.21 ppbv, a factor of 93% above pre-storm levels. In some events, mixing ratios reached the 10's of ppbv range and persisted overnight. These mixing ratios correspond to increases in the monoterpene emission rate, ranging from 120 to 1240 g km −2 h −1 compared to an estimated clear weather rate of 116 to 193 g km −2 h −1 . Considering the regularity of storm events over most forested areas, this could be an important factor to consider when modeling global monoterpene emissions and their resulting influence on the formation of organic aerosols.

New Hampshire↗
USGS2011

Changes in monoterpene mixing ratios during summer storms in rural New Hampshire (USA)

Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA). Emitted from vegetation, monoterpenes are a product of photosynthesis and act as a response to a variety of environmental factors. Most parameterizations of monoterpene emissions are based on clear weather models that do not take into account episodic conditions that can drastically change production and release rates into the atmosphere. Here, the monoterpene dataset from the rural Thompson Farm measurement site in Durham, New Hampshire is examined in the context of a set of known severe storm events. While some storm systems had a negligible influence on ambient monoterpene mixing ratios, the average storm event increased mixing ratios by 0.59 ± 0.21 ppbv, a factor of 93 % above pre-storm levels. In some events, mixing ratios reached the 10’s of ppbv range and persisted overnight. These mixing ratios correspond to increases in the monoterpene emission rate, ranging from 120 to 1240 g km−2 h −1 compared to an estimated clear weather rate of 116 to 193 g km−2 h −1 . Considering the regularity of storm events over most forested areas, this could be an important factor to consider when modeling global monoterpene emissions and their resulting influence on the formation of organic aerosols.

New Hampshire↗
USGS1996

Systematics of wolves in eastern North America

Cranial morphology of Recent wolves throughout northern and western North America is remarkably consistent. Statistical analysis indicates the presence of four subspecies of gray wolf (Canis lupus) there, which are always distinguishable from the sympatric coyote (C. latrans). A fifth gray wolf subspecies, lycaon, occurs in southeastern Canada, and the red wolf (C. rufus), is found in the southeast. During the early 1900s the coyote moved east of the prairies and hybridized with the native wolves, thereby creating much confusion. Nonetheless, analysis of every available specimen of wild Canis, dating from before the coyote invasion in the region east of the Mississippi River and south of Wisconsin, Michigan, and New York, does indicate the presence of a small wolf, distinct from the coyote and showing the statistical consistency of other wolf populations. That series also has close affinity to specimens of the red wolf collected in Louisiana and Missouri prior to 1925, and to Pleistocene fossils from the east. There was a sharp line of morphological distinction between the wolves of the eastern United States and those of the prairies, but a closer approach by the former to the subspecies lycaon, which in turn intergrades with gray wolf populations in western Ontario and Minnesota. Although gaps in our knowledge remain, a reasonable hypothesis is that the entire forested region from southeastern Canada to the Gulf Coast originally was inhabited by populations of small wolves, with a subspecific or specific line just south of the eastern Great Lakes. There is no evidence that southeastern North America ever was occupied by large gray wolves and coyotes that hybridized to form the red wolf.

Book chapter↗