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At least 1,693 records · Page 94Linked to original sources
USGS2024

A strategic and science-based framework for management of invasive annual grasses in the sagebrush biome

In the last 20 years, the North American sagebrush biome has lost over 500,000 ha of intact and largely intact sagebrush plant communities on an annual basis. Much of this loss has been associated with expansion and infilling of invasive annual grasses (IAGs). These species are highly competitive against native perennial grasses in disturbed environments, and create fuel conditions that increase both the likelihood of fire ignition and the ease of wildfire spread across large landscapes. Given the current rate of IAG expansion in both burned and unburned rangelands, ameliorating the IAG threat will involve a range-wide paradigm shift from opportunistic and reactive management, to a framework that spatially prioritizes maintenance of largely intact, uninvaded areas and improvement of invaded habitats in strategic locations. We created a framework accompanied by biome-wide priority maps using geospatial overlays that target areas to MAINTAIN large, uninvaded areas as natural resource anchors through activities to prevent IAGs and IMPROVE areas to reduce invasions with the highest potential for management efforts to succeed in restoring large, intact landscapes. We then offer three case studies to illustrate the use of these concepts and map products at multiple scales. Our map products operate at the biome scale using regional data sources but additional data sources may be needed to inform local conservation planning. However, the basic strategic management principles of a) maintaining the intact and uninvaded areas that we can least afford to lose to IAGs and b) improving areas where we have a higher likelihood of restoration success, is timely, relevant, and scalable from the biome to local levels.

Rangeland Ecology & Management↗
USGS2017

Monitoring land surface albedo and vegetation dynamics using high spatial and temporal resolution synthetic time series from Landsat and the MODIS BRDF/NBAR/albedo product

Seasonal vegetation phenology can significantly alter surface albedo which in turn affects the global energy balance and the albedo warming/cooling feedbacks that impact climate change. To monitor and quantify the surface dynamics of heterogeneous landscapes, high temporal and spatial resolution synthetic time series of albedo and the enhanced vegetation index (EVI) were generated from the 500 m Moderate Resolution Imaging Spectroradiometer (MODIS) operational Collection V006 daily BRDF/NBAR/albedo products and 30 m Landsat 5 albedo and near-nadir reflectance data through the use of the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM). The traditional Landsat Albedo (Shuai et al., 2011) makes use of the MODIS BRDF/Albedo products (MCD43) by assigning appropriate BRDFs from coincident MODIS products to each Landsat image to generate a 30 m Landsat albedo product for that acquisition date. The available cloud free Landsat 5 albedos (due to clouds, generated every 16 days at best) were used in conjunction with the daily MODIS albedos to determine the appropriate 30 m albedos for the intervening daily time steps in this study. These enhanced daily 30 m spatial resolution synthetic time series were then used to track albedo and vegetation phenology dynamics over three Ameriflux tower sites (Harvard Forest in 2007, Santa Rita in 2011 and Walker Branch in 2005). These Ameriflux sites were chosen as they are all quite nearby new towers coming on line for the National Ecological Observatory Network (NEON), and thus represent locations which will be served by spatially paired albedo measures in the near future. The availability of data from the NEON towers will greatly expand the sources of tower albedometer data available for evaluation of satellite products. At these three Ameriflux tower sites the synthetic time series of broadband shortwave albedos were evaluated using the tower albedo measurements with a Root Mean Square Error (RMSE) less than 0.013 and a bias within the range of ±0.006. These synthetic time series provide much greater spatial detail than the 500 m gridded MODIS data, especially over more heterogeneous surfaces, which improves the efforts to characterize and monitor the spatial variation across species and communities. The mean of the difference between maximum and minimum synthetic time series of albedo within the MODIS pixels over a subset of satellite data of Harvard Forest (16 km by 14 km) was as high as 0.2 during the snow-covered period and reduced to around 0.1 during the snow-free period. Similarly, we have used STARFM to also couple MODIS Nadir BRDF Adjusted Reflectances (NBAR) values with Landsat 5 reflectances to generate daily synthetic times series of NBAR and thus Enhanced Vegetation Index (NBAR-EVI) at a 30 m resolution. While normally STARFM is used with directional reflectances, the use of the view angle corrected daily MODIS NBAR values will provide more consistent time series. These synthetic times series of EVI are shown to capture seasonal vegetation dynamics with finer spatial and temporal details, especially over heterogeneous land surfaces.

International Journal of Applied Earth Observation↗
USGS2021

Historical changes in plant water use and need in the continental United States

A robust method for characterizing the biophysical environment of terrestrial vegetation uses the relationship between Actual Evapotranspiration (AET) and Climatic Water Deficit (CWD). These variables are usually estimated from a water balance model rather than measured directly and are often more representative of ecologically-significant changes than temperature or precipitation. We evaluate trends and spatial patterns in AET and CWD in the Continental United States (CONUS) during 1980–2019 using a gridded water balance model. The western US had linear regression slopes indicating increasing CWD and decreasing AET (drying), while the eastern US had generally opposite trends. When limits to plant performance characterized by AET and CWD are exceeded, vegetation assemblages change. Widespread increases in aridity throughout the west portends shifts in the distribution of plants limited by available moisture. A detailed look at Sequoia National Park illustrates the high degree of fine-scale spatial variability that exists across elevation and topographical gradients. Where such topographical and climatic diversity exists, appropriate use of our gridded data will require sub-setting to an appropriate area and analyzing according to categories of interest such as vegetation communities or across obvious physical gradients. Recent studies have successfully applied similar water balance models to fire risk and forest structure in both western and eastern U.S. forests, arid-land spring discharge, amphibian colonization and persistence in wetlands, whitebark pine mortality and establishment, and the distribution of arid-land grass species and landscape scale vegetation condition. Our gridded dataset is available free for public use. Our findings illustrate how a simple water balance model can identify important trends and patterns at site to regional scales. However, at finer scales, environmental heterogeneity is driving a range of responses that may not be simply characterized by a single trend.

PLoS ONE↗
USGS1996

Holocene paleoenvironments of Northeast Iowa

This paper presents the biotic, sedimentary, geomorphic, and climatic history of the upper part of the Roberts Creek Basin, northeastern Iowa for the late—glacial and Holocene, and compares these records with a C—O isotopic sequence from Coldwater Cave, 60 km northwest of Roberts Creek. The biotic record (pollen, vascular plant and bryophyte macrofossils, and insects) is preserved in floodplain alluvium that underlies three constructional surfaces separated by low scarps. Each surface is underlain by a lithologically and temporally distinct alluvial fill. The highest surface is underlain by the Gunder Member of the Deforest Formation, dating from 11 000 to 4000 yr BP; beneath the intermediate level is the Roberts Creek Member, dating from 4000 to 400 yr BP; and the lowest level is underlain by the Camp Creek Member, deposited during the last 380 yr. Pollen and plant macrofossils in the alluvial fill show that a typical late—glacial spruce forest was replaced by Quercus and Ulmus in the early Holocene. This early—to—middle Holocene forest became dominated by mesic elements such as Acer saccharum, Tilia americana, Ostrya virginiana, and Carpinus caroliniana as late as 5500 yr BP; in contrast, the closest sites to the west and north were at their warmest and driest and were covered by prairie vegetation between 6500 and 5500 yr BP. After 5500 yr BP, the forest in the Roberts Creek area was replaced by prairie, as indicated by a rich assemblage of plant macrofossils, although only Ambrosia and Poaceae became abundant in the pollen record. The return of Quercus ≈ 3000 BP (while nonarboreal pollen percentages remained relatively high) indicates that oak savanna prevailed with little change until settlement time. The bryophyte assemblages strongly support the vascular plant record. Rich fen species characteristic of boreal habitats occur only in the late—glacial. They are replaced by a number of deciduous—forest elements when early—to—middle Holocene forests were present, but mosses of forest habitats completely disappear when prairie became dominant. A few deciduous—forest taxa return during the late—Holocene, when oak savanna prevailed. The C—O isotopic record from stalagmite s in Coldwater Cave indicates a relatively stable environment from ≈ 8000 to 5100 yr BP, when the δ 13 C values indicate a change in vegetation dominated by C 3 (predominantly forest) to C 4 (predominantly prairie) plants. About 4900 yr BP, the rise in 18 O values indicates a temperature increase of ≈ 1.5 ° C. The fact that the vegetational change suggested by the δ 13 C values preceded the temperature increase suggests that fire may have been an important factor in converting forest to prairie. Abundant charred seeds and other plant material at Roberts Creek 4830 yr BP support this hypothesis. The 18 O values remain constant from ≈ 5100 to ≈ 3000 yr BP, but the δ 13 C values gradually rise, indicating that soil formed under forest takes at least 2000 yr for its carbon to reach equilibrium after replacement by prairie vegetation. The return of oak to form savanna is reflected in the gradual decline of δ 13 C values in the last 3000 yr BP; O isotopic values drop sharply by ≈ 1 ° C ≈ 2800 yr BP and then were relatively stable. In contrast to the vegetational and isotopic records, the insect assemblages suggest little change in the local environments throughout most of the Holocene. All of the beetle taxa presently occur in eastern Iowa. The relative stability through the Holocene indicates that both open grassland and riparian woodland elements were present throughout. Settlement, land clearing, and land cultivation by EuroAmericans in the region caused rapid erosion of the upland landscape, the deposition of 1—2 m of sediment across the floodplain, a replacement of the native vegetation with ruderal species, a decimation of the native insect fauna, and a degradation of water quality in the stream. These changes in the landscape, vegetation, and insect faunas are as striking as those associated with glacial—interglacial transitions. The timing and direction of changes in the vegetation at Roberts Creek generally correlate well with the carbon and oxygen isotopic record in speleothems at nearby Coldwater Cave and indicate that climate was the main forcing function. However, the contrast between the vegetational change and the stability of the beetle population suggests that climatic changes were subtle. We hypothesize that the factors involved in the Holocene changes were seasonal changes in temperature and precipitation that may not have resulted in much mean annual change. Such changes may have affected the vegetation more than the insect fauna.

Iowa↗
USGS2011

Native and exotic plants of fragments of sagebrush steppe produced by geomorphic processes versus land use

Habitat fragmentation and invasion by exotic species are regarded as major threats to the biodiversity of many ecosystems. We surveyed the plant communities of two types of remnant sagebrush-steppe fragments from nearby areas on the Snake River Plain of southeastern Idaho, USA. One type resulted from land use (conversion to dryland agriculture; hereafter AG Islands) and the other from geomorphic processes (Holocene volcanism; hereafter kipukas). We assessed two predictions for the variation in native plant species richness of these fragments, using structural equation models (SEM). First, we predicted that the species richness of native plants would follow the MacArthur–Wilson (M–W) hypothesis of island biogeography, as often is expected for the communities of habitat fragments. Second, we predicted a negative relationship between native and exotic plants, as would be expected if exotic plants are decreasing the diversity of native plants. Finally, we assessed whether exotic species were more strongly associated with the fragments embedded in the agricultural landscape, as would be expected if agriculture had facilitated the introduction and naturalization of non-native species, and whether the communities of the two types of fragments were distinct. Species richness of native plants was not strongly correlated with M–W characteristics for either the AG Islands or the **kipukas. The AG Islands had more species and higher cover of exotics than the kipukas, and exotic plants were good predictors of native plant species richness. Our results support the hypothesis that proximity to agriculture can increase the diversity and abundance of exotic plants in native habitat. In combination with other information, the results also suggest that agriculture and exotic species have caused loss of native diversity and reorganization of the sagebrush-steppe plant community.

Idaho↗
USGS2013

Estimated sediment thickness, quality, and toxicity to benthic organisms in selected impoundments in Massachusetts

The U.S. Geological Survey and the Massachusetts Department of Fish and Game, Division of Ecological Restoration, collaborated to collect baseline information on the quantity and quality of sediment impounded behind selected dams in Massachusetts, including sediment thickness and the occurrence of contaminants potentially toxic to benthic organisms. The thicknesses of impounded sediments were measured, and cores of sediment were collected from 32 impoundments in 2004 and 2005. Cores were chemically analyzed, and concentrations of 32 inorganic elements and 108 organic compounds were quantified. Sediment thicknesses varied considerably among the 32 impoundments, with an average thickness of 3.7 feet. Estimated volumes also varied greatly, ranging from 100,000 cubic feet to 81 million cubic feet. Concentrations of toxic contaminants as well as the number of contaminants detected above analytical quantification levels (also known as laboratory reporting levels) varied greatly among sampling locations. Based on measured contaminant concentrations and comparison to published screening thresholds, bottom sediments were predicted to be toxic to bottom-dwelling (benthic) organisms in slightly under 30 percent of the impoundments sampled. Statistically significant relations were found between several of the contaminants and individual indicators of urban land use and industrial activity in the upstream drainage areas of the impoundments. However, models developed to estimate contaminant concentrations at unsampled sites from upstream landscape characteristics had low predictive power, consistent with the long and complex land-use history that is typical of many drainage areas in Massachusetts.

Massachusetts↗
USGS2015

Predicting Brook Trout occurrence in stream reaches throughout their native range in the eastern United States

The Brook Trout Salvelinus fontinalis is an important species of conservation concern in the eastern USA. We developed a model to predict Brook Trout population status within individual stream reaches throughout the species’ native range in the eastern USA. We utilized hierarchical logistic regression with Bayesian estimation to predict Brook Trout occurrence probability, and we allowed slopes and intercepts to vary among ecological drainage units (EDUs). Model performance was similar for 7,327 training samples and 1,832 validation samples based on the area under the receiver operating curve (∼0.78) and Cohen's kappa statistic (0.44). Predicted water temperature had a strong negative effect on Brook Trout occurrence probability at the stream reach scale and was also negatively associated with the EDU average probability of Brook Trout occurrence (i.e., EDU-specific intercepts). The effect of soil permeability was positive but decreased as EDU mean soil permeability increased. Brook Trout were less likely to occur in stream reaches surrounded by agricultural or developed land cover, and an interaction suggested that agricultural land cover also resulted in an increased sensitivity to water temperature. Our model provides a further understanding of how Brook Trout are shaped by habitat characteristics in the region and yields maps of stream-reach-scale predictions, which together can be used to support ongoing conservation and management efforts. These decision support tools can be used to identify the extent of potentially suitable habitat, estimate historic habitat losses, and prioritize conservation efforts by selecting suitable stream reaches for a given action. Future work could extend the model to account for additional landscape or habitat characteristics, include biotic interactions, or estimate potential Brook Trout responses to climate and land use changes.

Connecticut, Delaware, Maine, Maryland, Massachuse↗
USGS2010

Thresholds in forest bird occurrence as a function of the amount of early-seral broadleaf forest at landscape scales

Recent declines in broadleaf-dominated, early-seral forest globally as a function of intensive forest management and/or fire suppression have raised concern about the viability of populations dependent on such forest types. However, quantitative information about the strength and direction of species associations with broadleaf cover at landscape scales are rare. Uncovering such habitat relationships is essential for understanding the demography of species and in developing sound conservation strategies. It is particularly important to detect points in habitat reduction where rates of population decline may accelerate or the likelihood of species occurrence drops rapidly (i.e., thresholds). Here, we use a large avian point-count data set ( N = 4375) from southwestern and northwestern Oregon along with segmented logistic regression to test for thresholds in forest bird occurrence as a function of broadleaf forest and early-seral broadleaf forest at local (150-m radius) and landscape (500–2000-m radius) scales. All 12 bird species examined showed positive responses to either broadleaf forest in general, and/or early-seral broadleaf forest. However, regional variation in species response to these conditions was high. We found considerable evidence for landscape thresholds in bird species occurrence as a function of broadleaf cover; threshold models received substantially greater support than linear models for eight of 12 species. Landscape thresholds in broadleaf forest ranged broadly from 1.35% to 24.55% mean canopy cover. Early-seral broadleaf thresholds tended to be much lower (0.22–1.87%). We found a strong negative relationship between the strength of species association with early-seral broadleaf forest and 42-year bird population trends; species most associated with this forest type have declined at the greatest rates. Taken together, these results provide the first support for the hypothesis that reductions in broadleaf-dominated early-seral forest due to succession and intensive forest management have led to population declines of constituent species in the Pacific northwestern United States. Forest management treatments that maintain or restore even small amounts of broadleaf vegetation could mitigate further declines.

Oregon↗
USGS2019

Spatial patterns of meadow sensitivities to interannual climate variability in the Sierra Nevada

Conservation of montane meadows is a high priority for land and water managers given their critical role in buffering the effects of climate variability and their vulnerability to increasing temperatures and evaporative demands. Recent advances in cloud computing have provided new opportunities to examine ecological responses to climate variability over the past few decades, and at large spatial scales. In this study we characterized the sensitivities (magnitude and direction of the slope) of meadow vegetation responses to interannual variations in climate. We calculated sensitivity as the regression slope between a 35-year (1985-2016) time series of Landsat-derived vegetation indices characterizing late-season vegetation vigor and water balance variables from the Basin Characterization Model. We identified April 1 snowpack as the climate variable the majority of meadows were most sensitive to. We assessed how vegetation sensitivities to snowpack varied with hydrogeomorphic context (e.g., climate, geology, soils, watershed geometry and land cover) across the Sierra Nevada mountain range using factor analysis to reduce the dimensionality of the hydrogeomorphic data, and multiple linear regression to model sensitivity responses. We found that meadow sensitivities to snowpack varied with long-term average meadow climate, indicators of watershed subsurface water storage capacity, and indicators of meadow vegetation composition. Alpine and sub-alpine meadows with high average annual precipitation, but limited catchment subsurface storage exhibited the largest sensitivities. Our results provide a novel regional perspective on spatial patterns of meadow sensitivities to climate variability and the landscape-scale hydrogeomorphic factors that influence late-season water availability in meadow ecosystems in the Sierra Nevada.

Sierra Nevada↗
USGS2020

Cryptic lives of conspicuous animals: Otolith chemistry chronicles life histories of coastal lagoon fishes

Bar-built coastal lagoons are dynamic ecosystems at the land-sea interface that are important habitats for a variety of species. This study examined the habitat ecology of two lagoon species, the endangered Tidewater Goby ( Eucyclogobius newberryi ) and the Prickly Sculpin ( Cottus asper ) by reconstructing individual life histories from patterns in the concentration of the element Sr (as ratioed to Ca; Sr:Ca) in otoliths. Specific objectives were to (1) elucidate any movements of individual fishes among three primary habitat components of typical bar-built lagoon systems: coastal ocean, brackish lagoon, and freshwater watershed streams, and (2) determine if either species exhibited a consistent life history as defined by a stereotypical otolith Sr:Ca chronology, which could be indicative of a consistent range of salinity or temperature occupied through ontogeny. Results suggested that Tidewater Goby was a lagoon resident and that Prickly Sculpin exhibited migrations between lagoon and watershed stream habitats. There was no strong evidence in either species of ocean occupancy or of a stereotypical Sr:Ca chronology, the latter suggesting the full range of available lagoon habitat in terms of salinity and temperature was likely utilized at all life stages. These findings add to the body of evidence that bar-built lagoons are not isolated habitats, and holistic management of these habitats with adjoining watershed and marine environments could increase habitat connectivity across the landscape, with potential benefits to fishes.

California↗
USGS2025

Land use and soil characteristics are associated with increased risk of treponeme-associated hoof disease in elk

Environments can shape the occurrence and extent of disease outbreaks in wildlife. We studied the effects of environmental features on the occurrence of treponeme-associated hoof disease (TAHD), an emerging infectious disease of free-ranging elk ( Cervus canadensis ), in southwestern Washington, USA. During the 2016–2022 harvest seasons, successful elk hunters returned mandatory harvest reports and noted the presence or absence of hoof abnormalities indicative of TAHD. We used generalized linear models and an information-theoretic approach to model selection to relate (1) the spatial distribution of hoof abnormalities to features of landscapes (land cover, topography, and soil characteristics) and (2) the temporal distribution of hoof abnormalities to precipitation during the year preceding the harvest season. The probability of hoof disease increased with soil clay content and proportion of agricultural land (88% of model weight). We found no conclusive evidence for an effect of precipitation on the occurrence of TAHD, but this could relate to relatively high annual precipitation (>140 cm) in the study area. Nevertheless, disease cases may have been negatively associated with precipitation during February–June (55% of model weight). Soils and land management practices may increase the risk of hoof disease by promoting the survival of pathogens that cause TAHD, the susceptibility of elk to infection, or the intensity of pathogen transmission among elk when congregated. Focusing on areas where the risk of disease is greatest may facilitate the detection of TAHD during surveillance. Likewise, removing infected elk and dispersing uninfected elk from areas with the greatest risk of disease may enhance the effectiveness of efforts to reduce transmission. Basing this work on the knowledge that disease risk is modified by factors of hosts, pathogens, and environments, this study serves as an application of the epidemiological triad framework to better understand the ecology and epidemiology of an emerging infectious disease in wildlife.

Washington↗
USGS2018

Drivers of chaparral plant diversity

Chaparral diversity has marked spatial and temporal variation. Evolutionary diversity at the genetic, specific, and lineage level contribute to a very diverse flora. Ecological diversity is evident in life histories that comprise a range of physiological and morphological strategies for dealing with drought, and demographic patterns centered around different seedling recruitment strategies. Community or alpha diversity varies markedly through time. Mature chaparral ranges from monotypic stands of chamise ( Adenostoma fasciculatum ) to mixed chaparral often with up to a dozen shrub species. The understory contributes relatively little other than a few diminutive annuals and occasional herbaceous perennial resprouts. However, after fire, diversity increases dramatically and is often dominated by annuals that arise from a dormant seedbank with significant contribution of geophytes resprouting and flowering from dormant bulbs and corms. This flora has very diverse life histories, with some present only a year or two and then existing as a dormant seedbank or bulbs until the next fire. Others may persist much longer, often in gaps in the shrub canopy. Postfire dominance-diversity patterns fit a geometric model as most communities are dominated by a few species and the bulk of the flora comprise subordinates that occupy specific microhabitats. Postfire community assembly is a result of competitive interactions and environmental filtering effects. Beta diversity plays a role in community assembly for as heterogeneity of communities in the landscape increases, the potential species pool for a community increases. Gamma diversity is particularly high because species turnover across latitudinal and elevational gradients is high. The role of diversity in conferring community resilience is complex and a function of the life history of shrub dominants and the historical patterns of fires. Under some circumstances low diversity may be more resilient than high diversity, for example under high fire frequency monotypic stands of Adenostoma fasciculatum may resist change better than diverse stands that include obligate seeding shrubs sensitive to short interval fires. Postfire annuals also are sensitive to short interval fires as these disturbances enhance the invasion by more competitive non-native grasses. Expected increases in anthropogenic ignitions due to population growth are the biggest threat to biodiversity in chaparral.

Book chapter↗
USGS2015

Experimental evidence of spatial memory and home range affinity in White-tailed Deer ( Odocoileus virginianus )

The role of spatial memory in the movement of animals through landscapes remains elusive. To examine spatial memory and home range affinity of White-tailed Deer ( Odocoileus virginianus ) in northeastern Minnesota during 1995–2007, I translocated 17 adult does with known home ranges to unfamiliar sites and radio-tracked them after their release. Twelve does wearing transmitting radio-collars returned to their home ranges. Death and collar expiration precluded determination of whether the remaining five does would have returned to home ranges. Three of five does wearing global positioning system collars traveled throughout hundreds of square kilometres, circling, backtracking, and returning to release sites, while two others exhibited directional movement for tens of kilometres. Four does that survived to parturition stopped traveling and moved at hourly rates similar to those of control does during the first three weeks of the typical fawn-rearing period, but continued traveling later. Their aberrant extensive travel before and after interruption by parturition suggests that they recognized they were in unfamiliar areas, demonstrating both their capacity and propensity to search for and occupy the familiar space of their individual home ranges. Their successful return to home ranges provided experimental evidence of spatial memory and further elucidated its pervasive role in White-tailed Deer spatial ecology.

Canadian Field-Naturalist↗
USGS2019

Review of Sky dance of the woodcock: The habits and habitats of a strange little bird by Greg Hoch

American Woodcock ( Scolopax minor ) have enthralled conservationists (including Aldo Leopold), bird watchers, wildlife enthusiasts, hunters, and others interested in the natural world for centuries. No doubt, woodcock also have enthralled humans in North America for millennia prior to written descriptions of the woodcock’s courtship displays, habitat preferences, and curious behavior and anatomy. As perhaps the most extensively studied species of shorebird in the world, there is a rich and extensive literature, both scientific and popular, focused on woodcock ecology, behavior, and hunting. To that extensive body of literature, Sky Dance of the Woodcock provides an updated summary of their natural history, habitat relations, and conservation. Sky Dance of the Woodcock takes its title from the courtship display of male woodcock, which consists of an elaborate aerial flight incorporating sound produced both vocally and mechanically via highly modified flight feathers. The aerial displays are accompanied by similarly unusual behavior on the ground, including a distinctive ‘peent’ call. This courtship display happens across much of eastern North America each spring, and Hoch uses this wonder to capture the imagination of the readers of his text. Hoch begins the book with an overview of some of the mystery and fascination surrounding woodcock and builds from that opening to describe woodcock anatomy, natural history, and behavior, before describing their courtship display in greater detail. From there, Hoch describes woodcock-habitat relations, provides a historical overview of woodcock hunting, identifies current threats to woodcock populations, summarizes past and recent woodcock research, and finally, presents an updated overview of woodcock conservation and habitat management. Throughout, there is sometimes surprising information about things as simple as what woodcock eat, to more complex assessment of how woodcock use landscapes and migrate to and from spring and summer breeding areas. This book will undoubtedly appeal to woodcock enthusiasts of a variety to stripes. Woodcock hunters and bird watchers alike will learn something about woodcock-habitat relations, behavior, and conservation. Professional biologists and researchers will benefit from Hoch’s synthesis of a wide range of information about woodcock, and landowners and managers can use some of the concepts in this book to inform their decisions about how to manage lands under their control. Along the way, everyone who reads Sky Dance of the Woodcock is likely to come away with an enhanced appreciation of this captivating bird.

Prairie Naturalist↗
USGS2001

Interactions between fire and invasive plants in temperate grasslands of North America

A substantial number of invasive grasses, forbs and woody plants have invaded temperate grasslands in North America. Among the invading species are winter annuals, biennials, cool-season perennials, warm-season perennials, vines, shrubs, and trees. Many of these species have been deliberately introduced and widely planted; some are still used for range improvement, pastures, lawns, and as ornamentals, though many are listed as state or federal noxious weeds. Others have been greatly facilitated by widespread land disturbance. Historically, fire has been a major selective force in the evolution of temperate grasslands. Further, prescribed fire is commonly used as a method of ecological management for native grassland communities as well as in conjunction with restoration efforts. Within this context, it is important to understand how invasive species will interact with natural and prescribed fire regimes. In this paper, we consider what is known about how exotic species that invade temperate grasslands relate to fire. The primary issues addressed for each species are (1) Does fire appear to enhance colonization? (2) To what degree does fire affect the survival of plants? (3) Are plants that are burned able to regrow following fire and, if so, how rapidly can they recover? (4) How important is competition with native species to the response to fire? and (5) What effect does an invasive species have on the characteristics of the fire regime? For many species, results are preliminary, incomplete, or inconsistent among studies. For this reason, many of the conclusions drawn for individual species must be considered preliminary. Based on analyses of individual species, a conceptual framework is presented for considering how invasive plants may interact with fire when they invade an ecosystem. The major categories of influences are the native community, the fire regime, growth conditions for both invasive and native species, and influences that disturbances, human impacts, and landscape characteristics have had in the past and will have in the future. The examples considered in this paper provide support for a few, tentative generalizations. First, among our current worst invaders of temperate grasslands, adaptation to fire is quite variable. Some species are not well adapted to burning and can be easily eliminated; other species are better adapted but can still be eliminated if fire occurs during periods of particular vulnerability and/or at high frequency. There is a set of species that is extremely well adapted to fire and will not be eliminated through burning alone. Second, competitive interactions with native species play a crucial role in the success of nonnative invaders. In cases where differential burn responses between invasive and native species can be exploited, and adequate populations of native dominant species are present, fire can sometimes tip the competitive balance away from invasives. Third, there are a few invasive species that have exceptional attributes and for which there are no easy solutions. The ability of cheatgrass ( Bromus tectorum ) to enhance fire, the ability of Chinese tallow ( Triadica sebifera ) to suppress fire, and the ability of leafy spurge ( Euphorbia esula ) to resprout from repeated injury make these species exceptional threats to native diversity. Finally, the available information for many invasive species is very incomplete, partic- ularly with regard to how fire affects competitive interactions with the native community. There is much more we need to know if we are to consistently predict how invasive species will respond to fire and how burning can best be used to manage for natural diversity.

Conference Paper↗
USGS2003

Surface Water in Hawaii

Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source of drinking water in some places. Streams also are a source of hydroelectric power, provide important riparian and instream habitats for many unique native species, support traditional and customary Hawaiian gathering rights and the practice of taro cultivation, and possess valued aesthetic qualities. Streams affect the physical, chemical, and aesthetic quality of receiving waters, such as estuaries, bays, and nearshore waters, which are critical to the tourism-based economy of the islands. Streams in Hawaii pose a danger because of their flashy nature; a stream's stage, or water level, can rise several feet in less than an hour during periods of intense rainfall. Streams in Hawaii are flashy because rainfall is intense, drainage basins are small, basins and streams are steep, and channel storage is limited. Streamflow generated during periods of heavy rainfall has led to loss of property and human lives in Hawaii. Most Hawaiian streams originate in the mountainous interiors of the islands and terminate at the coast. Streams are significant sculptors of the Hawaiian landscape because of the erosive power of the water they convey. In geologically young areas, such as much of the southern part of the island of Hawaii, well-defined stream channels have not developed because the permeability of the surface rocks generally is so high that rainfall infiltrates before flowing for significant distances on the surface. In geologically older areas that have received significant rainfall, streams and mass wasting have carved out large valleys.

Fact Sheet↗
USGS2017

Field-trip guide to mafic volcanism of the Cascade Range in Central Oregon—A volcanic, tectonic, hydrologic, and geomorphic journey

The Cascade Range in central Oregon has been shaped by tectonics, volcanism, and hydrology, as well as geomorphic forces that include glaciations. As a result of the rich interplay between these forces, mafic volcanism here can have surprising manifestations, which include relatively large tephra footprints and extensive lava flows, as well as water shortages, transportation and agricultural disruption, and forest fires. Although the focus of this multidisciplinary field trip will be on mafic volcanism, we will also look at the hydrology, geomorphology, and ecology of the area, and we will examine how these elements both influence and are influenced by mafic volcanism. We will see mafic volcanic rocks at the Sand Mountain volcanic field and in the Santiam Pass area, at McKenzie Pass, and in the southern Bend region. In addition, this field trip will occur during a total solar eclipse, the first one visible in the United States in more than 25 years (and the first seen in the conterminous United States in more than 37 years). The Cascade Range is the result of subduction of the Juan de Fuca plate underneath the North American plate. This north-south-trending volcanic mountain range is immediately downwind of the Pacific Ocean, a huge source of moisture. As moisture is blown eastward from the Pacific on prevailing winds, it encounters the Cascade Range in Oregon, and the resulting orographic lift and corresponding rain shadow is one of the strongest precipitation gradients in the conterminous United States. We will see how the products of the volcanoes in the central Oregon Cascades have had a profound influence on groundwater flow and, thus, on the distribution of Pacific moisture. We will also see the influence that mafic volcanism has had on landscape evolution, vegetation development, and general hydrology.

Oregon↗
USGS2017

Simulating ungulate herbivory across forest landscapes: A browsing extension for LANDIS-II

Browsing ungulates alter forest productivity and vegetation succession through selective foraging on species that often dominate early succession. However, the long-term and large-scale effects of browsing on forest succession are not possible to project without the use of simulation models. To explore the effects of ungulates on succession in a spatially explicit manner, we developed a Browse Extension that simulates the effects of browsing ungulates on the growth and survival of plant species cohorts within the LANDIS-II spatially dynamic forest landscape simulation model framework. We demonstrate the capabilities of the new extension and explore the spatial effects of ungulates on forest composition and dynamics using two case studies. The first case study examined the long-term effects of persistently high white-tailed deer browsing rates in the northern hardwood forests of the Allegheny National Forest, USA. In the second case study, we incorporated a dynamic ungulate population model to simulate interactions between the moose population and boreal forest landscape of Isle Royale National Park, USA. In both model applications, browsing reduced total aboveground live biomass and caused shifts in forest composition. Simulations that included effects of browsing resulted in successional patterns that were more similar to those observed in the study regions compared to simulations that did not incorporate browsing effects. Further, model estimates of moose population density and available forage biomass were similar to previously published field estimates at Isle Royale and in other moose-boreal forest systems. Our simulations suggest that neglecting effects of browsing when modeling forest succession in ecosystems known to be influenced by ungulates may result in flawed predictions of aboveground biomass and tree species composition.

Ecological Modelling↗