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USGS2012

Effects of spatial subsidies and habitat structure on the foraging ecology and size of geckos

While it is well established that ecosystem subsidies—the addition of energy, nutrients, or materials across ecosystem boundaries—can affect consumer abundance, there is less information available on how subsidy levels may affect consumer diet, body condition, trophic position, and resource partitioning among consumer species. There is also little information on whether changes in vegetation structure commonly associated with spatial variation in subsidies may play an important role in driving consumer responses to subsidies. To address these knowledge gaps, we studied changes in abundance, diet, trophic position, size, and body condition of two congeneric gecko species ( Lepidodactylus spp.) that coexist in palm dominated and native (hereafter dicot dominated) forests across the Central Pacific. These forests differ trongly both in the amount of marine subsidies that they receive from seabird guano and carcasses, and in the physical structure of the habitat. Contrary to other studies, we found that subsidy level had no impact on the abundance of either gecko species; it also did not have any apparent effects on resource partitioning between species. However, it did affect body size, dietary composition, and trophic position of both species. Geckos in subsidized, dicot forests were larger, had higher body condition and more diverse diets, and occupied a much higher trophic position than geckos found in palm dominated, low subsidy level forests. Both direct variation in subsidy levels and associated changes in habitat structure appear to play a role in driving these responses. These results suggest that variation in subsidy levels may drive important behavioral responses in predators, even when their numerical response is limited. Strong changes in trophic position of consumers also suggest that subsidies may drive increasingly complex food webs, with longer overall food chain length.

Palmyra Atoll↗

USGS2015

Landscape-level terrestrial methane flux observed from a very tall tower

Simulating the magnitude and variability of terrestrial methane sources and sinks poses a challenge to ecosystem models because the biophysical and biogeochemical processes that lead to methane emissions from terrestrial and freshwater ecosystems are, by their nature, episodic and spatially disjunct. As a consequence, model predictions of regional methane emissions based on field campaigns from short eddy covariance towers or static chambers have large uncertainties, because measurements focused on a particular known source of methane emission will be biased compared to regional estimates with regards to magnitude, spatial scale, or frequency of these emissions. Given the relatively large importance of predicting future terrestrial methane fluxes for constraining future atmospheric methane growth rates, a clear need exists to reduce spatiotemporal uncertainties. In 2010, an Ameriflux tower (US-PFa) near Park Falls, WI, USA, was instrumented with closed-path methane flux measurements at 122 m above ground in a mixed wetland–upland landscape representative of the Great Lakes region. Two years of flux observations revealed an average annual methane (CH 4 ) efflux of 785 ± 75 mg C CH 4 m −2 yr −1 , compared to a mean CO 2 sink of −80 g C CO 2 m −2 yr −1 , a ratio of 1% in magnitude on a mole basis. Interannual variability in methane flux was 30% of the mean flux and driven by suppression of methane emissions during dry conditions in late summer 2012. Though relatively small, the magnitude of the methane source from the very tall tower measurements was mostly within the range previously measured using static chambers at nearby wetlands, but larger than a simple scaling of those fluxes to the tower footprint. Seasonal patterns in methane fluxes were similar to those simulated in the Dynamic Land Ecosystem Model (DLEM), but magnitude depends on model parameterization and input data, especially regarding wetland extent. The model was unable to simulate short-term (sub-weekly) variability. Temperature was found to be a stronger driver of regional CH 4 flux than moisture availability or net ecosystem production at the daily to monthly scale. Taken together, these results emphasize the multi-timescale dependence of drivers of regional methane flux and the importance of long, continuous time series for their characterization.

Wisconsin↗

USGS2022

Avian community response to a novel environment: Commercial forestry in the Campos grasslands of South America

Establishing commercial tree plantations in native grassland ecosystems introduces a different structural and functional vegetation cover type, with expected implications for biodiversity. To better understand biodiversity responses to afforestation, we conducted a resource-use study with birds as a focal group, during the 2013–2014 breeding season in the Northern Campos grasslands of Uruguay. We sampled birds in native environments and plantations of loblolly pine ( Pinus taeda ) and flooded gum ( Eucalyptus grandis ) at different rotation stages. We recorded 103 species during 1,573 visits (10-min, 50-meter radius point counts) to 570 stratified sampling units. Native grasslands and forests exhibited greater diversity and had greater variability in species composition than structurally homogeneous plantations. Avian communities in plantations had distinct species combinations and relative abundances not found in native conditions. Avian communities in older plantations were more similar to native forests while those of newly-planted stands were more like grasslands. However, plantations were dominated by habitat generalists and some forest-dependent species, with negligible use by grassland specialist birds. Our results suggest the best conservation opportunities for grassland-dependent birds in afforested systems of the Campos of Uruguay may depend on diverse landscape-level measures rather than stand-level management practices. Albeit our research constituted a comprehensive assessment of bird taxonomic alpha and beta diversity, research on complementary diversity facets and multi-scale resource selection and demographic studies are needed to better understand the fitness implications for conserving and managing grassland birds in afforested landscapes.

Campos grasslands↗

USGS2023

Spatial variation in density of American black bears in northern Yellowstone National Park

The quality and availability of resources are known to influence spatial patterns of animal density. In Yellowstone National Park, relationships between the availability of resources and the distribution of grizzly bears ( Ursus arctos ) have been explored but have yet to be examined in American black bears ( Ursus americanus ). We conducted non-invasive genetic sampling during 2017–2018 (mid-May to mid-July) and applied spatially explicit capture-recapture models to estimate density of black bears and examine associations with landscape features. In both years, density estimates were higher in forested vegetation communities, which provide food resources and thermal and security cover preferred by black bears, compared with non-forested areas. In 2017, density also varied by sex, with female densities being higher than males. Based on our estimates, the northern range of Yellowstone National Park supports one of the highest densities of black bears (20 black bears/100 km 2 ) in the northern Rocky Mountains (6–12 black bears/100 km 2 in other regions). Given these high densities, black bears could influence other wildlife populations more than previously thought, such as through displacement of sympatric predators from kills. Our study provides the first spatially explicit estimates of density for black bears within an ecosystem that contains the majority of North America's large mammal species. Our density estimates provide a baseline that can be used for future research and management decisions of black bears, including efforts to reduce human–bear conflicts.

Montana, Wyoming↗

USGS2019

Invasive buffelgrass detection using high-resolution satellite and UAV imagery on Google Earth Engine

Methods to detect and monitor the spread of invasive grasses are critical to avoid ecosystem transformations and large economic costs. The rapid spread of non‐native buffelgrass (Pennisetum ciliare) has intensified fire risk and is replacing fire intolerant native vegetation in the Sonoran Desert of the southwestern US. Coarse‐resolution satellite imagery has had limited success in detecting small patches of buffelgrass, whereas ground‐based and aerial survey methods are often cost prohibitive. To improve detection, we trained 2 m resolution DigitalGlobe WorldView‐2 satellite imagery with 12 cm resolution unmanned aerial vehicle (UAV) imagery and classified buffelgrass on Google Earth Engine, a cloud computing platform, using Random Forest (RF) models in Saguaro National Park, Arizona, USA. Our classification models had an average overall accuracy of 93% and producer's accuracies of 94–96% for buffelgrass, although user's accuracies were low. We detected a 2.92 km 2 area of buffelgrass in the eastern Rincon Mountain District (1.07% of the total area) and a 0.46 km 2 area (0.46% of the total area) in the western Tucson Mountain District of Saguaro National Park. Buffelgrass cover was significantly greater in the Sonoran Paloverde‐Mixed Cacti Desert Scrub vegetation type, on poorly developed Entisols and Inceptisol soils and on south‐facing topographic aspects compared to other areas. Our results demonstrate that high‐resolution imagery improve on previous attempts to detect and classify buffelgrass and indicate potential areas where the invasive grass might spread. The methods demonstrated in this study could be employed by land managers as a low‐cost strategy to identify priority areas for control efforts and continued monitoring.

Arizona↗

USGS2008

Fire and nonnative invasive plants in the central bioregion

The Central bioregion is a vast area, stretching from Canada to Mexico and from the eastern forests to the Rocky Mountains, dominated by grasslands and shrublands, but inclusive of riparian and other forests. This bioregion has been impacted by many human induced changes, particularly relating to agricultural practices, over the past 150 years. Also changed are fire regimes, first by native peoples who used fire for a variety of purposes and then by European settlers, who directly and indirectly contributed to a great reduction in the frequency of fire on the landscape. Perhaps of even greater importance has been the introduction of nonnative plant species, which have come to impact every community type to some degree. Nonnative plants have a wide array of impacts on native ecosystems and populations in the Central bioregion, and these impacts continue to mount and evolve. Many long-time invaders, such as smooth brome (Bromus inermis), and leafy spurge (Euphorbia esula), have already spread to large areas, and their ranges may still be expanding. Others, such as tamarisk or saltcedar (Tamarix spp.) and buffelgrass (Pennisetum ciliare), are rapidly spreading at the present time, while still others have likely not yet shown their full potential for expansion. In this volume, as well as in this chapter, our emphasis is on the interaction of nonnatives with fire, how it affects them and how they affect it. The ecosystems of the Central bioregion have been shaped by fire, including fires associated with natural ignitions and those deliberately set by humans. Both grasslands and shrublands in this bioregion experienced frequent and widespread fires during their evolution (Stewart 2002). Prescribed fire is now widely used to manage some areas for their natural characteristics. Thus, while changed in character, both by conditions that now limit wildfire occurrence and spread and by prescribed burning, the Central bioregion remains one with a high fire frequency (Wade and others 2000). Fire interactions with nonnative plants can have important impacts. In some cases, fire can be a means of reducing impacts of nonnative species (chapter 4). In other cases, fire may facilitate the establishment and spread of nonnatives (chapter 2). Some nonnative species can radically change the fire regime itself (chapter3). Because of the widespread use of prescribed fire in this bioregion, it is important to know how nonnative species interact with fire and whether there are means whereby these interactions can be controlled.

Great Plains↗

USGS2020

The response of streams to changes in atmospheric deposition of sulfur and nitrogen in the Adirondack Mountains

Acidic deposition is the result of upwind sulfur (S) and nitrogen (N) emissions into the atmosphere from human activities. Environmental impacts from acidic deposition across forested landscapes include acidification of soil and drainage water, depletion of available soil nutrient bases, and impacts to and changes in forest and aquatic species composition and biodiversity. Acidic deposition can mobilize aluminum (Al) from soil-to-soil solution and subsequently to drainage water in forms that can be toxic to aquatic life. When exposed to decreasing levels of acidic deposition, which has been occurring in New York since the late 1970s, some soils and drainage waters have become gradually less acidic. Remaining questions relate to effects on stream resources, anticipated resource recovery under increasingly lower levels of deposition, and the levels of deposition (target loads, TLs) needed to reach a range of stream ecosystem recovery targets. Environmental scientists commonly estimate thresholds of air pollutant emissions and resulting atmospheric deposition at which adverse ecological effects are manifested. This analysis is often done using critical loads (CL) and/or TLs, using approaches that account for the spatial and temporal aspects of acidification and recovery. Exceedance represents the extent to which current levels of acidic deposition exceed the level expected to cause ecological harm. The research reported here is intended to help address S and N deposition TLs and ecosystem recovery of Adirondack streams, a resource that has been less thoroughly investigated than lakes. The overarching goal of this work is to highlight key considerations that will help inform decision-makers and ecosystem managers who are responsible for environmental policy in New York State and beyond. Salient aspects of stream TL modeling are discussed with an aim of informing not only scientists, but also policymakers, ecosystem managers, and nonscientists who are required to make decisions related to the effects of acidic deposition on natural ecosystems. Analyses reported herein quantify relations among chemical indicators and metrics of fish community health and biodiversity in streams of the Adirondack Park. This information is used to indicate levels of atmospheric deposition necessary to alleviate harmful effects on fish populations. Results of this investigation provide a framework that can be applied to better understand how modeled stream acid neutralizing capacity (ANC) values that are developed to support TL investigations can be adjusted to reflect high-flow ANC values that may be associated with toxic conditions. Since process models are often calibrated to a low-flow or average flow condition, the magnitude and spatial extent of TL exceedances increase substantially when episodic acidification is considered.

New York↗

USGS2024

A review of the ecology and conservation biology of Sali (Micronesian Starling, Aplonis opaca guami) on Guam

The accidental introduction of the Brown Treesnake (BTS, Boiga irregularis ) to Guam following World War II led to the extinction, extirpation, or severe decline of most of Guam’s native avifauna. One forest bird species that managed to persist is the cavity-nesting Såli (Micronesian Starling, Aplonis opaca guami ), a once-ubiquitous native omnivore whose current Guam distribution is restricted primarily to urbanized areas in the northern half of the island, with a second much smaller population on Cocos Island off southern Guam. Såli on Guam breed year-round and are habitat generalists with large home ranges. Besides arthropods and small vertebrates, they consume fruit from a wide range of native and introduced plant species and are key seed dispersers within the local ecosystem. Såli on Guam suffer extremely high post-fledging mortality due to predation by BTS and cats, leading to a population age structure strongly skewed towards adult birds. Other threats include habitat loss and degradation, extreme weather events, and sea level rise. Key management activities aimed at restoring this species include predator control, while non-native ungulate removal and vegetation management may be undertaken to support broader ecological recovery. This species account on Såli provides a review of the literature on this species, synthesizing information on habitat use, life history, and demographics to provide a biological foundation for future recovery efforts.

Micronesica↗

USGS2024

Non-native Rhizophora mangle as sinks for coastal contamination on Moloka'i, Hawai'i

Coastal mangrove forests provide a suite of environmental services, including sequestration of anthropogenic contamination. Yet, research lags on the environmental fate and potential human health risks of mangrove-sequestered contaminants in the context of mangrove removal for development and range shifts due to climate change. To address this, we conducted a study on Moloka'i, Hawai'i, comparing microplastic and pesticide contamination in coastal compartments both at areas modified by non-native red mangroves ( Rhizophora mangle ) and unmodified, open coastline. Sediment, porewater, and mangrove plant tissues were collected to quantify microplastic and pesticide concentrations across ecosystem type. Average microplastics were similar between mangrove (8.89 items/kg) and non-mangrove areas (9.01 items/kg) in sediment and porewater, but mangrove roots were a substantial reservoir of microplastics (2004 items/kg). Additionally, there was a strong relationship between proximity to urban development and microplastics detected. Six pesticides were detected, most commonly the insecticide bifenthrin, found in most sediment samples (11.3 ng/g), all root samples (243.3 ng/g), and one propagule sample (8.60 ng/g). Other pesticides detected with appreciable concentrations include the neonicotinoid insecticide imidacloprid and the legacy insecticide transformation product, p,p’-DDE. The other detections, all at concentrations < 1 ng/g, were p,p’-DDT, trifluralin, and permethrin. The high concentrations of bifenthrin in roots compared to lower concentrations detected in sediment suggest that mangrove roots strongly accumulate some pesticides, indicating mangrove roots as a sink for organic contaminants. Study methods could be applied to other Hawaiian Islands and other locations where mangroves have been introduced to further examine the observed trends. Additional information is needed to investigate the fate and cycling of pesticides and microplastics adhered to mangrove roots, to better inform non-native mangrove removal efforts on Moloka'i and elsewhere.

Hawaii↗

USGS2000

Hurricanes, coral reefs and rainforests: resistance, ruin and recovery in the Caribbean

The coexistence of hurricanes, coral reefs, and rainforests in the Caribbean demonstrates that highly structured ecosystems with great diversity can flourish in spite of recurring exposure to intense destructive energy. Coral reefs develop in response to wave energy and resist hurricanes largely by virtue of their structural strength. Limited fetch also protects some reefs from fully developed hurricane waves. While storms may produce dramatic local reef damage, they appear to have little impact on the ability of coral reefs to provide food or habitat for fish and other animals. Rainforests experience an enormous increase in wind energy during hurricanes with dramatic structural changes in the vegetation. The resulting changes in forest microclimate are larger than those on reefs and the loss of fruit, leaves, cover, and microclimate has a great impact on animal populations. Recovery of many aspects of rainforest structure and function is rapid, though there may be long-term changes in species composition. While resistance and repair have maintained reefs and rainforests in the past, human impacts may threaten their ability to survive.

Ambio↗

USGS2019

The long-term effects of Hurricanes Wilma and Irma on soil elevation change in Everglades mangrove forests

Mangrove forests in the Florida Everglades (USA) are frequently affected by hurricanes that produce high-velocity winds, storm surge, and extreme rainfall, but also provide sediment subsidies that help mangroves adjust to sea-level rise. The long-term influence of hurricane sediment inputs on soil elevation dynamics in mangrove forests are not well understood. Here, we assessed the effects of sediment deposition during Hurricanes Wilma (2005) and Irma (2017) on soil elevation change at two mangrove forests located along the Shark and Lostmans Rivers in Everglades National Park. We used surface elevation change data from a sixteen-year period (2002-2018), measured with the surface elevation table-marker horizon (SET-MH) approach. At the Shark River mangrove forest, we used marker horizons and a combination of deep, shallow, and original SETs to quantify the contributions of four soil zones to net soil elevation change. Rates of elevation change were greatly influenced by storm sediments. Abrupt increases in elevation due to sediment inputs and subsurface expansion during Hurricane Wilma were followed by: (1) an initial post-hurricane period of elevation loss due to erosion of hurricane sediments and subsurface contraction; (2) a secondary period of elevation gain due primarily to accretion; and (3) an abrupt elevation gain due to new sediment inputs during Hurricane Irma. Our findings suggest that elevation change in hurricane-affected mangrove forests can be cyclical or include disjunct phases, which is critical information for advancing the understanding of wetland responses to accelerated sea-level rise given the expectation of increasing storm intensity due to climate change.

Florida↗

USGS2023

The effects of landscape and yard features on mammal diversity in residential yards within Northwest Arkansas, USA

The human footprint is rapidly expanding, and wildlife habitat is continuously being converted to human residential properties. Surviving wildlife that reside in developing areas are displaced to nearby undeveloped areas. However, some animals can co-exist with humans and acquire the necessary resources (food, water, shelter) within the human environment. This ability to coexist may be particularly true when development is low intensity, as in residential suburban yards. Yards are individually managed “greenspaces” that can provide a range of food (e.g., bird feeders, compost, gardens), water (bird baths and garden ponds), and shelter (e.g., brush-piles, outbuildings) resources and are surrounded by varying landscape cover. To evaluate which residential landscape and yard features influence the richness and diversity of mammalian herbivores and mesopredators; we deployed wildlife game cameras throughout Northwestern Arkansas, USA in 46 residential yards in summer 2021 and 96 yards in summer 2022. We found that mesopredator diversity had a negative relationship with fences and was positively influenced by the number of bird feeders present in a yard. Mesopredator richness increased with the amount of forest within 400 m of the camera. Herbivore diversity and richness were positively correlated to the area of forest within 400 m surrounding yard and by garden area within yards, respectively. Our results suggest that while landscape does play a role in the presence of wildlife in a residential area, homeowners also have agency over the richness and diversity of mammals using their yards based on the features they create or maintain on their properties.

Arkansas↗

USGS2009

Using LiDAR and quickbird data to model plant production and quantify uncertainties associated with wetland detection and land cover generalizations

Spatiotemporal data from satellite remote sensing and surface meteorology networks have made it possible to continuously monitor global plant production, and to identify global trends associated with land cover/use and climate change. Gross primary production (GPP) and net primary production (NPP) are routinely derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard satellites Terra and Aqua, and estimates generally agree with independent measurements at validation sites across the globe. However, the accuracy of GPP and NPP estimates in some regions may be limited by the quality of model input variables and heterogeneity at fine spatial scales. We developed new methods for deriving model inputs (i.e., land cover, leaf area, and photosynthetically active radiation absorbed by plant canopies) from airborne laser altimetry (LiDAR) and Quickbird multispectral data at resolutions ranging from about 30??m to 1??km. In addition, LiDAR-derived biomass was used as a means for computing carbon-use efficiency. Spatial variables were used with temporal data from ground-based monitoring stations to compute a six-year GPP and NPP time series for a 3600??ha study site in the Great Lakes region of North America. Model results compared favorably with independent observations from a 400??m flux tower and a process-based ecosystem model (BIOME-BGC), but only after removing vapor pressure deficit as a constraint on photosynthesis from the MODIS global algorithm. Fine-resolution inputs captured more of the spatial variability, but estimates were similar to coarse-resolution data when integrated across the entire landscape. Failure to account for wetlands had little impact on landscape-scale estimates, because vegetation structure, composition, and conversion efficiencies were similar to upland plant communities. Plant productivity estimates were noticeably improved using LiDAR-derived variables, while uncertainties associated with land cover generalizations and wetlands in this largely forested landscape were considered less important.

Remote Sensing of Environment↗

USGS2005

Environmental impacts of oil production on soil, bedrock, and vegetation at the U.S. Geological Survey Osage-Skiatook Petroleum Environmental Research site A, Osage County, Oklahoma

The U.S. Geological Survey is investigating the impacts of oil and gas production on soils, groundwater, surface water, and ecosystems in the United States. Two sites in northeastern Oklahoma (sites A and B) are presently being investigated under the Osage–Skiatook Petroleum Environmental Research project. Oil wells on the lease surrounding site A in Osage County, Oklahoma, produced about 100,000 bbl of oil between 1913 and 1981. Prominent production features on the 1.5-ha (3.7-ac) site A include a tank battery, an oil-filled trench, pipelines, storage pits for both produced water and oil, and an old power unit. Site activities and historic releases have left open areas in the local oak forest adjacent to these features and a deeply eroded salt scar downslope from the pits that extends to nearby Skiatook Lake. The site is underlain by surficial sediments comprised of very fine-grained eolian sand and colluvium as much as 1.4 m (4.6 ft) thick, which, in turn, overlie flat-lying, fractured bedrock comprised of sandstone, clayey sandstone, mudstone, and shale. A geophysical survey of ground conductance and concentration measurements of aqueous extracts (1:1 by weight) of core samples taken in the salt scar and adjacent areas indicate that unusual concentrations of NaCl-rich salt are present at depths to at least 8 m (26 ft) in the bedrock; however, little salt occurs in the eolian sand. Historic aerial photographs, anecdotal reports from oil-lease operators, and tree-ring records indicate that the surrounding oak forest was largely established after 1935 and thus postdates the majority of surface damage at the site. Blackjack oaks adjacent to the salt scar have anomalously elevated chloride ( 400 ppm) in their leaves and record the presence of NaCl-rich salt or salty water in the shallow subsurface. The geophysical measurements also indicate moderately elevated conductance beneath the oak forest adjoining the salt scar.

Oklahoma↗

USGS2022

Within-marsh and landscape features structure ribbed mussel distribution in Georgia, USA, marshes

Ribbed mussels, Geukensia demissa , are marsh fauna that are used in coastal management and restoration due to the ecosystem services they provide. Ribbed mussel restoration efforts may be improved with a greater understanding of the environmental drivers of ribbed mussel distribution at multiple spatial scales to predict areas where restoration could be successful. This study sought to estimate the effects of within-marsh (4 m) and landscape (500 m) factors on ribbed mussel distribution. Ribbed mussel densities were surveyed at 11 sites along the coast of Georgia, USA, and overlaid with spatial data for within-marsh factors (elevation, distance to marsh features, slope) as well as landscape factors (percent cover by subtidal creek, forest, and development within a 500-m radius). The distribution model was then validated using three previously unsurveyed marshes and explained 55% of the variance in ribbed mussel abundance. Ribbed mussel abundances and occupancy were most sensitive to changes in within-marsh factors (elevation and distance to subtidal creeks, bodies of water inundated during the full tidal cycle) but were also sensitive to landscape features (percent landcover of forests and development). The highest ribbed mussel densities were found in mid-elevation areas (~ 0.7 m NAVD88), far from subtidal creeks, and in marshes surrounded with forest and development. These results contrast with distributions in the northeastern USA, where ribbed mussels are distributed along subtidal creek banks. This work suggests that restoration may be most effective when focused on appropriate elevations and at locations away from the marsh-creek ecotone.

Georgia↗

USGS2003

Mapping vegetation in Yellowstone National Park using spectral feature analysis of AVIRIS data

Knowledge of the distribution of vegetation on the landscape can be used to investigate ecosystem functioning. The sizes and movements of animal populations can be linked to resources provided by different plant species. This paper demonstrates the application of imaging spectroscopy to the study of vegetation in Yellowstone National Park (Yellowstone) using spectral feature analysis of data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). AVIRIS data, acquired on August 7, 1996, were calibrated to surface reflectance using a radiative transfer model and field reflectance measurements of a ground calibration site. A spectral library of canopy reflectance signatures was created by averaging pixels of the calibrated AVIRIS data over areas of known forest and nonforest vegetation cover types in Yellowstone. Using continuum removal and least squares fitting algorithms in the US Geological Survey's Tetracorder expert system, the distributions of these vegetation types were determined by comparing the absorption features of vegetation in the spectral library with the spectra from the AVIRIS data. The 0.68 μm chlorophyll absorption feature and leaf water absorption features, centered near 0.98 and 1.20 μm, were analyzed. Nonforest cover types of sagebrush, grasslands, willows, sedges, and other wetland vegetation were mapped in the Lamar Valley of Yellowstone. Conifer cover types of lodgepole pine, whitebark pine, Douglas fir, and mixed Engelmann spruce/subalpine fir forests were spectrally discriminated and their distributions mapped in the AVIRIS images. In the Mount Washburn area of Yellowstone, a comparison of the AVIRIS map of forest cover types to a map derived from air photos resulted in an overall agreement of 74.1% (kappa statistic=0.62).

Wyoming↗

USGS2016

A review of the relationships between drought and forest fire in the United States

The historical and pre-settlement relationships between drought and wildfire are well documented in North America, with forest fire occurrence and area clearly increasing in response to drought. There is also evidence that drought interacts with other controls (forest productivity, topography, fire weather, management activities) to affect fire intensity, severity, extent, and frequency. Fire regime characteristics arise across many individual fires at a variety of spatial and temporal scales, so both weather and climate—including short- and long-term droughts—are important and influence several, but not all, aspects of fire regimes. We review relationships between drought and fire regimes in United States forests, fire-related drought metrics and expected changes in fire risk, and implications for fire management under climate change. Collectively, this points to a conceptual model of fire on real landscapes: fire regimes, and how they change through time, are products of fuels and how other factors affect their availability (abundance, arrangement, continuity) and flammability (moisture, chemical composition). Climate, management, and land use all affect availability, flammability, and probability of ignition differently in different parts of North America. From a fire ecology perspective, the concept of drought varies with scale, application, scientific or management objective, and ecosystem.

Global Change Biology↗

USGS2011

Cougar space use and movements in the wildland-urban landscape of western Washington

The wildland-urban interface lies at the confluence of human-dominated and wild landscapes, creating a number of management and conservation challenges. Because wildlife ecology, behavior, and evolution at this interface are shaped by both natural and human phenomena, this requires greater understanding of how diverse factors affect ecosystem and population processes. We illustrate the challenge of understanding and managing a frequent and often undesired inhabitant of the wildland-urban landscape, the cougar (Puma concolor). In wildland and residential areas of western Washington State, USA, we captured and radiotracked 27 cougars to model space use and understand the role of landscape features in interactions (sightings, encounters, and depredations) between cougars and humans. Resource utilization functions (RUFs) identified cougar use of areas with features that were probably attractive to prey, influential on prey vulnerability, and associated with limited or no residential development. Early-successional forest (+), conifer forest (+), distance to road (-), residential density (-), and elevation (-) were significant positive and negative predictors of use for the population, whereas use of other landscape features was highly variable. Space use and movement rates in wildland and residential areas were similar because cougars used wildland-like forest patches, reserves, and corridors in residential portions of their home range. The population RUF was a good predictor of confirmed cougar interactions, with 72% of confirmed reports occurring in the 50% of the landscape predicted to be medium-high and high cougar use areas. We believe that there is a threshold residential density at which the level of development modifies the habitat but maintains enough wildland characteristics to encourage moderate levels of cougar use and maximize the probability of interaction. Wildlife managers trying to reduce interactions between cougars and people should incorporate information on spatial ecology and landscape characteristics to identify areas with the highest overlap of human and cougar use to focus management, education, and landscape planning. Resource utilization functions provide a proactive tool to guide these activities for improved coexistence with wildlife using both wildland and residential portions of the landscape. ??2011 by the Ecological Society of America.

Ecological Applications↗