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At least 991 records · Page 55Linked to original sources
USGS2016

Mountain goat abundance and population trends in the Olympic Mountains, northwestern Washington, 2016

Executive Summary We estimated abundance and trends of non-native mountain goats ( Oreamnos americanus ) in the Olympic Mountains of northwestern Washington, based on aerial surveys conducted during July 13–24, 2016. The surveys produced the seventh population estimate since the first formal aerial surveys were conducted in 1983. This was the second population estimate since we adjusted survey area boundaries and adopted new estimation procedures in 2011. Before 2011, surveys encompassed all areas free of glacial ice at elevations above 1,520 meters (m), but in 2011 we expanded survey unit boundaries to include suitable mountain goat habitats at elevations between 1,425 and 1,520 m. In 2011, we also began applying a sightability correction model allowing us to estimate undercounting bias associated with aerial surveys and to adjust survey results accordingly. The 2016 surveys were carried out by National Park Service (NPS) personnel in Olympic National Park and by Washington Department of Fish and Wildlife (WDFW) biologists in Olympic National Forest and in the southeastern part of Olympic National Park. We surveyed a total of 59 survey units, comprising 55 percent of the 60,218-hectare survey area. We estimated a mountain goat population of 623 ±43 (standard error, SE). Based on this level of estimation uncertainty, the 95-percent confidence interval ranged from 561 to 741 mountain goats at the time of the survey. We examined the rate of increase of the mountain goat population by comparing the current population estimate to previous estimates from 2004 and 2011. Because aerial survey boundaries changed between 2004 and 2016, we recomputed population estimates for 2011 and 2016 surveys based on the revised survey boundaries as well as the previously defined boundaries so that estimates were directly comparable across years. Additionally, because the Mount Washington survey unit was not surveyed in 2011, we used results from an independent survey of the Mount Washington unit conducted by WDFW biologists in 2012 and combined it with the 2011 survey results to produce a complete survey conducted over 2 years. The revised estimates of mountain goat abundance occurring at elevations above 1,520 m were 230 ±19 (SE) in 2004, 350 ±41 (SE) in 2011, and 584 ±39 (SE) in 2016. The difference between the overall 2016 population estimate (623 ±43 [SE]) and the smaller estimate (584 ±39 [SE]) reflected the number of mountain goats counted in the expanded survey areas added in 2011. Based on comparisons within the standardized survey boundary, the mountain goat population in the Olympic Mountains increased at an average finite rate of 6 percent annually from 2004 to 2011, 11 percent annually from 2011 to 2016, and 8 percent annually over the combined period. We caution that the population may have been underestimated in 2011 because of record heavy snows persisting into the survey season. Therefore, the rate of population increase from 2011 and 2016 may be overestimated. The rate of increase measured over the combined period (2004–16) may be more representative of the recent population growth. We conclude that the abundance of mountain goats has increased for more than a decade, and if the recent average rate of population growth were sustained, the population would increase by 45 percent over the next 5 years.

Washington↗
USGS2020

Northward migration of the Oregon forearc on the Gales Creek fault

The Gales Creek fault (GCF) is a 60-km-long, northwest-striking dextral fault system (west of Portland, Oregon) that accommodates northward motion and uplift of the Oregon Coast Range. New geologic mapping and geophysical models confirm inferred offsets from earlier geophysical surveys and document ∼12 km of right-lateral offset of a basement high in Eocene Siletz River Volcanics since ca. 35 Ma and ∼8.8 km of right-lateral separation of Miocene Columbia River Basalt at Newberg, Oregon, since 15 Ma (∼0.62 ± 0.12 mm/yr, average long-term rate). Relative uplift of Eocene Coast Range basalt basement west of the fault zone is at least 5 km based on depth to basement under the Tualatin Basin from a recent inversion of gravity data. West of the city of Forest Grove, the fault consists of two subparallel strands ∼7 km apart. The westernmost, Parsons Creek strand, forms a linear valley southward to Henry Hagg Lake, where it continues southward to Newberg as a series of en echelon strands forming both extensional and compressive step-overs. Compressive step-overs in the GCF occur at intersections with ESE-striking sinistral faults crossing the Coast Range, suggesting the GCF is the eastern boundary of an R′ Riedel shear domain that could accommodate up to half of the ∼45° of post–40 Ma clockwise rotation of the Coast Range documented by paleomagnetic studies. Gravity and magnetic anomalies suggest the western strands of the GCF extend southward beneath Newberg into the Northern Willamette Valley, where colinear magnetic anomalies have been correlated with the Mount Angel fault, the proposed source of the 1993 M 5.7 Scotts Mills earthquake. The potential-field data and water-well data also indicate the eastern, Gales Creek strand of the fault may link to the NNW-striking Canby fault through the E-W Beaverton fault to form a 30-km-wide compressive step-over along the south side of the Tualatin Basin. LiDAR data reveal right-lateral stream offsets of as much as 1.5 km, shutter ridges, and other youthful geomorphic features for 60 km along the geophysical and geologic trace of the GCF north of Newberg, Oregon. Paleoseismic trenches document Eocene bedrock thrust over 250 ka surficial deposits along a reverse splay of the fault system near Yamhill, Oregon, and Holocene motion has been recently documented on the GCF along Scoggins Creek and Parsons Creek. The GCF could produce earthquakes in excess of Mw 7, if the entire 60 km segment ruptured in one earthquake. The apparent subsurface links of the GCF to other faults in the Northern Willamette Valley suggest that other faults in the system may also be active.

Oregon↗
USGS2005

Habitats used by black and surf scoters in eastern North America as determined by satellite radio telemetry

Satellite radio telemetry was used to determine the movements and habitats of black scoters (Melanitta nigra) and surf scoters (Melanitta perspicillata) in eastern North America. A total of 21 surf scoters were instrumented during five years (2001-05) and 32 black scoters were instrumented during three years (2002-04) with implanted PTT 100 satellite transmitters (39 g) with external antenna. Nesting habitat of black scoters was more open than surf scoters (44% vs. 11%), whereas nesting habitat for surf scoters was located in more forested areas (66% vs. 20%). Locations of black scoters in breeding areas on average were at significantly higher latitude and lower elevations than sites used by surf scoters. Satellite telemetry determined that James Bay was the major molting area for male black and surf scoters, although some males molted along the coast of Labrador-Newfoundland. Black scoters instrumented on the Restigouche River, which is a major staging area, were widely distributed along the Atlantic Coast from Cape Cod to Georgia during winter. Major wintering areas for black scoters were Cape Cod (Martha's Vineyard and Nantucket Island), Long Island, and New Jersey. In these northern marine wintering areas, black scoters were located farther from shore (4.2 km) and in deeper water (8.3 m) than black scoters in more southern estuarine areas, where distance from shore was 3.1 km and water depth was 5.2 m. Surf scoters instrumented in Chesapeake Bay in late winter showed a strong tendency to return to the Bay the following winter after they had migrated to and from breeding areas. In Chesapeake Bay, black scoters and surf scoters were located mostly in mesohaline areas that had similar water depths (5.1 m vs. 7.5 m) and distances from shore (3.0 km vs. 2.9 km). Distance from shore and depth of water increased over time during the winter for both species. Updated information from the ARGOS Systems aboard the NOAA satellites on scoter movements was made accessible on the Patuxent Website.

Book chapter↗
USGS2014

Trails through time: A geologist's guide to Jefferson County open space parks

Introduction Jefferson County straddles one of the most conspicuous and important geographic and geologic boundaries in western North America, the eastern flank of the Rocky Mountains. To the east you can travel 1,100 miles across Great Plains and Central Lowlands before you sight the western foothills of the Appalachians. If you travel in the other direction you will cross or skirt mountain range after mountain range until you sight the Coast Range near San Francisco, more than 900 miles to the west. Many of these mountains have different ages and origins than the Colorado mountains, but they are all part of the great mountain belt called the North American Cordillera that extends along the western edge of the continent from Alaska through Mexico. What is the reason for the remarkably straight and abrupt eastern flank of the Colorado Front Range? The brief answer is that it marks the edge of a block of ancient metamorphic and igneous rocks that has been uplifted relative to younger flat-laying sedimentary rocks that underlie the plains to the east. During the uplift, the sedimentary rocks along the boundary have been uplifted and tilted eastward to form the discontinuous line of hogback ridges that parallel the mountain front. Erosion during and after the uplift has removed the sedimentary rocks that once lay above the harder rocks of the mountain uplift, carved the scenic peaks and mountain canyons in the hard crystalline rocks of uplifted block, and worn away the softer layers of sedimentary rocks of the plains, but left a few of the harder upturned layers along the mountain front as hogback ridges. Jefferson County Open Space Parks, as well as other nearby parks and National Forest lands, offer marvelous opportunities to explore the geologic story behind this singular landscape. At first the distribution of rocks of different ages and types seems almost random, but careful study of the rocks and landscape features reveals a captivating geologic story, a history that tells of the building of the foundations of the continent, the rise and destruction of longvanished mountain ranges, the ebb and flow of ancient seas, and the constant shaping and reshaping of the landscape in response to the never-ending interplay between uplift and erosion. This historical account is constantly being improved and expanded as new evidence accumulates and new interpretations evolve.

Colorado↗
USGS2019

Recreational impacts to wildlife: Managing visitors and resources to protect wildlife

Publication Abstract: Visitor use management is essential for maximizing benefits for visitors while achieving and maintaining desired resource conditions and visitor experiences on federally managed lands and waters. Visitor capacity, a component of visitor use management, is defined as the maximum amounts and types of visitor use that an area can accommodate while achieving and maintaining the desired resource conditions and visitor experiences that are consistent with the purposes for which the area was established. This visitor capacity guidebook, in combination with the “Visitor Use Management Framework” (the framework), provides managers with processes to collaboratively develop long-term strategies to manage the amounts and types of visitor use to protect resources, improve access, connect visitors to key experiences, and achieve desired conditions. The purpose of this guidebook is to provide cohesive guidance on identifying and implementing visitor capacity on federally managed lands and waters. Similar to the framework, the sliding scale of analysis is discussed throughout this guidebook to ensure the investment of time, money, and other resources for a project is commensurate with the complexity of the project and the consequences of the decision. Overall, this guidebook is meant to expand on the framework and guide a professional and consistent approach to identifying and implementing visitor capacity. Paper Abstract: Most protected natural areas, including parks, forests, and wildlife refuges, are managed under a dual mandate to preserve predominantly natural settings and processes while also accommodating recreational visitation. Visitor activities can have deleterious impacts to protected area vegetation, soil, water, wildlife, and cultural resources. The term impact denotes undesirable visitor-related effects to natural resources and/or wildlife. This paper reviews the management of recreation impacts to wildlife, including discussions of influential factors, impact indicators, and the range of management responses. This information is provided to assist recreation and land managers in avoiding or minimizing visitor impact to wildlife, particularly related to decision-making within the new Visitor Use Management (VUM) framework. Such decision-making requires a thorough understanding of the different types of wildlife impact and the use-related, environmental, and managerial factors that influence them.

Report↗
USGS2007

Paleoenvironmental Assessment and Deglacial Chronology of the Onondaga Trough, Onondaga County, New York

Introduction The U.S. Geological Survey, in cooperation with the Onondaga Lake Partnership and Onondaga Environmental Institute, has been studying the hydrogeology of the Onondaga Trough since 2002 to determine the movement and concentration of naturally occurring brine in the glacial valley-fill aquifer. Numerous shallow and deep test holes have been drilled to determine the glacial and water-quality stratigraphy in the Onondaga Trough. Organic materials were recovered from the Onondaga Creek, Ninemile Creek, and Harbor Brook valleys, and from lakebed sediments in Onondaga Lake (fig. 1) and age-dated with carbon-isotope analysis techniques. This report summarizes the carbon-isotope data collected from 1996 through 2006 in the Onondaga Trough. The results of these analyses provide a means to understand the deglaciation of the watershed and the development of the watershed from barren glacial sediment to a forested ecosystem.

Open-File Report↗
USGS2019

Shining light on the storm: In-stream optics reveal hysteresis of dissolved organic matter character

The quantity and character of dissolved organic matter (DOM) can change rapidly during storm events, affecting key biogeochemical processes, carbon bioavailability, metal pollutant transport, and disinfection byproduct formation during drinking water treatment. We used in situ ultraviolet–visible spectrophotometers to concurrently measure dissolved organic carbon (DOC) concentration and spectral slope ratio, a proxy for DOM molecular weight. Measurements were made at 15-minute intervals over three years in three streams draining primarily agricultural, urban, and forested watersheds. We describe storm event dynamics by calculating hysteresis indices for DOC concentration and spectral slope ratio for 220 storms and present a novel analytical framework that can be used to interpret these metrics together. DOC concentration and spectral slope ratio differed significantly among sites, and individual storm DOM dynamics were remarkably variable at each site and among the three sites. Distinct patterns emerged for storm DOM dynamics depending on land use/land cover (LULC) of each watershed. In agricultural and forested streams, DOC concentration increased after the time of peak discharge, and spectral slope ratio dynamics indicate that this delayed flux was of relatively higher molecular weight material compared to the beginning of each storm. In contrast, DOM character during storms at the urban stream generally shifted to lower molecular weight while DOC concentration increased on the falling limb, indicating either the introduction of lower molecular weight DOM, the exhaustion of a higher molecular weight DOM sources, or a combination of these factors. We show that the combination of high-frequency DOM character and quantity metrics have the potential to provide new insight into short-timescale DOM dynamics and can reveal previously unknown effects of LULC on the chemical nature, source, and timing of DOM export during storms.

Vermont↗
USGS2018

Ecological drought: Accounting for the non-human impacts of water shortage in the Upper Missouri Headwaters Basin, Montana, USA

Water laws and drought plans are used to prioritize and allocate scarce water resources. Both have historically been human-centric, failing to account for non-human water needs. In this paper, we examine the development of instream flow legislation and the evolution of drought planning to highlight the growing concern for the non-human impacts of water scarcity. Utilizing a new framework for ecological drought, we analyzed five watershed-scale drought plans in southwestern Montana, USA to understand if, and how, the ecological impacts of drought are currently being assessed. We found that while these plans do account for some ecological impacts, it is primarily through the narrow lens of impacts to fish as measured by water temperature and streamflow. The latter is typically based on the same ecological principles used to determine instream flow requirements. We also found that other resource plans in the same watersheds (e.g., Watershed Restoration Plans, Bureau of Land Management (BLM) Watershed Assessments or United States Forest Service (USFS) Forest Plans) identify a broader range of ecological drought risks. Given limited resources and the potential for mutual benefits and synergies, we suggest greater integration between various planning processes could result in a more holistic consideration of water needs and uses across the landscape.

Montana↗
USGS2019

Paleoclimate of the subtropical Andes during the latest Miocene, Lauca Basin, Chile

Uplift of the Andean Cordillera during the Miocene and Pliocene produced large-scale changes in regional atmospheric circulation that impacted local ecosystems. The Lauca Basin (northern Chilean Altiplano) contains variably fluvial and lacustrine sedimentary sequences spanning the interval from 8.7 to 2.3 Ma. Field samples were collected from paleo-lacustrine sediments in the basin. Sediments were dated using detrital zircon geochronology on volcanic tuffs, yielding an age range between ~5.57 and 5.44 Ma. These new age constraints provided an opportunity to evaluate changes in the Lauca Basin ecosystem across this dynamic Miocene-Pliocene transition. We employed multiple proxies (lithofacies analysis, diatoms, pollen, and oxygen stable isotopes of authigenic carbonates) to interpret ancient lacustrine and terrestrial paleoenvironments. Alternations among mudstone, carbonate, and evaporitic facies indicate lake-level variability through time. The diatom assemblage is characterized by meso- to hypersaline and alkaline-tolerant taxa typical of shallow lakes. The δ 18 O values ranged from −8.96 to −2.22‰ indicating fluctuations in water balance. Pollen taxa in the outcrop are typical of a transitional stage between seasonal cloud forest and open grassland. Together, these proxies indicate that the Lauca paleolake sediments were deposited under a wetter-than-modern climate with high temporal variability. Our results refine previous studies in the Lauca Basin and are consistent with other regional studies suggesting that the South American summer monsoon at the Miocene-Pliocene transition was more intense than it is at present.

Palaeogeography, Palaeoclimatology, Palaeoecology↗
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.

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