Skip to main content
Advanced Search

Filters: Tags: {"type":"Organization","name":"national casc"} (X) > Date Range: {"choice":"year"} (X) > Extensions: Citation (X) > Types: Citation (X)

25 results (165ms)   

View Results as: JSON ATOM CSV
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
Abstract: The Land Transformation Model (LTM) is hierarchically coupled with meso-scale drivers to project urban growth across the conterminous USA. Quantity of urban growth at county and place (i.e., city) scales is simulated using population, urban density and nearest neighbor dependent attributes. We compared three meso-scale LTMs to three null models that lack meso-scale drivers. Models were developed using circa 1990–2000 data and validated using change in the 2001 and 2006 National Land Cover Databases (NLCD). LTM and null models were assessed using the mean difference in quantity between simulated and actual growth measured at multiple spatial scales. We found that LTM models performed relatively well at...
Categories: Publication; Types: Citation; Tags: National CASC
Changes in the Earth’s climate are expected to impact freshwater habitats around the world by altering water temperatures, water levels, and streamflow. These changes will have consequences for inland fish – those found within lakes, rivers, streams, canals, reservoirs, and other landlocked waters – which are important for food, commerce, and recreation around the world. According to the U.S. Fish and Wildlife Service, in 2011, 33.1 million people fished and spent $41.8 billion in the United States alone. Yet to date, little comprehensive research has been conducted to investigate the effects of climate change on inland fisheries at a large scale. The aim of this project was to summarize the current state of knowledge,...
Abstract: Coastal mangrove–freshwater marsh ecotones of the Everglades represent transitions between marine salt-tolerant halophytic and freshwater salt-intolerant glycophytic communities. It is hypothesized here that a self-reinforcing feedback, termed a “vegetation switch,” between vegetation and soil salinity, helps maintain the sharp mangrove–marsh ecotone. A general theoretical implication of the switch mechanism is that the ecotone will be stable to small disturbances but vulnerable to rapid regime shifts from large disturbances, such as storm surges, which could cause large spatial displacements of the ecotone. We develop a simulation model to describe the vegetation switch mechanism. The model couples vegetation...
Abstract (from ScienceDirect): We present the first high resolution (1:20,000) river centerlines shapefiles from 50 large rivers across the world. Rivers were selected based on the criteria of having more than 1000 km length and which have been reported to have a significant contribution to global fishery production. Since large rivers often span multiple countries, the degree of changes (i.e., anthropogenic or climate derived) varies from region to region. These high-resolution layers were developed to enable researchers to delineate accurate river length, from headwaters regions to their delta and assess or visualize the ongoing changes more accurately in these river systems. Further, these polylines could be...
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
Abstract: Macrophyte removal by lakefront property owners occurs on glacial lakes throughout the range of Largemouth Bass Micropterus salmoides, yet little information exists on how it affects recruitment of these fish populations. We hypothesized that with greater prey availability in macrophytes, age‐0 Largemouth Bass consumption and growth would increase. To test this hypothesis, we conducted an in‐lake experiment with age‐0 Largemouth Bass in twelve 9.29‐m2 littoral mesocosms in glacial Chancellor Lake, Michigan, during summer and fall 2014. We removed macrophytes from mesocosm substrates to produce low‐coverage, high‐coverage, and vegetation edge treatments and determined treatment effects on consumption and...
Abstract: Field observations and numerical simulations indicate that the 6-to-30-km-wide mangrove forest along the Gulf Coast of South Florida effectively attenuated storm surges from a Category 3 hurricane, Wilma, and protected the inland wetland by reducing an inundation area of 1800 km2 and restricting surge inundation inside the mangrove zone. The surge amplitude decreases at a rate of 40–50 cm/km across the mangrove forest and at a rate of 20 cm/km across the areas with a mixture of mangrove islands with open water. In contrast, the amplitudes of storm surges at the front of the mangrove zone increase by about 10–30% because of the “blockage” of mangroves to surge water, which can cause greater impacts on structures...
Natural selection may result in local adaptation to different environmental conditions across the range of a species. Understanding local adaptation, in turn, informs management decisions such as translocation to restore locally-extinct populations. We used a landscape genomics approach to detect genetic signatures of selection related to climatic variation among desert bighorn sheep populations across their indigenous range in the western United States. This approach allowed us to investigate broad patterns of both neutral and adaptive genetic variation across very different environments. Analyses suggested that ancestry and isolation by distance were the most significant forces driving genetic variation in desert...
Abstract: Population persistence across broad spatial scales (e.g., watersheds) can depend on asynchronous dynamics among populations at finer scales (e.g., streams or habitats). We applied a von Bertalanffy growth model and closed N‐mixture abundance model in a hierarchical Bayesian framework to examine effects of fine‐scale variability in temperature and density dependence on growth and abundance as well as within‐ versus among‐stream variability in growth and abundance of Rio Grande Cutthroat Trout Oncorhynchus clarkii virginalis (RGCT) in northern New Mexico streams. An accumulation of degree‐days positively influenced instantaneous growth rates and, to a lesser extent, negatively affected asymptotic body length....
Scenario planning is one decision support method that can help natural resource managers incorporate information about uncertain future changes in climate into management decisions. To provide a proof of concept of the value of scenario planning in helping managers prepare for climate change, we conducted a pilot scenario planning effort aimed at helping state agencies in the northeastern United States develop climate-informed moose management goals and actions. To encourage participation by wildlife managers, we provided several opportunities for them to learn about scenario planning and examples of its application in natural resource management. We shared this information via guidance documents on incorporating...
Northeastern boreal forests are an important habitat for many wildlife species, including migratory birds and moose. These animals play vital roles in the boreal forest ecosystem, are a source of pleasure for bird and wildlife watchers, and contribute to tourism revenue for many communities. However, moose and migratory birds are thought to be particularly vulnerable to the impacts of climate change. For example, in New York’s Adirondack State Park, six species of boreal birds have shown population declines over the past ten years. Meanwhile, moose in many parts of the northeast are threatened by winter ticks that thrive in warmer climates and spread disease. Building upon earlier work related to climate impacts...
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
Abstract (from AFS): Many Bluegill Lepomis macrochirus populations are dominated by fish ≤125 mm total length (TL) that may be underrepresented when using standard sampling gears. To identify efficient sampling methods for these populations, we compared catch per unit effort (CPUE) and TL frequency distributions of Bluegill captured in cloverleaf traps, boat electrofishing, mini‐fyke nets, and beach seine hauls from two northern Wisconsin lakes supporting populations dominated by fish ≤125 mm TL. Mean Bluegill CPUE ranged from 41 (SE = 11) fish per cloverleaf trap lift to 16 (SE = 8) fish per beach seine haul. Cloverleaf traps generally captured smaller Bluegill relative to other gears and were the only gear to...
Abstract (from AFS): Managing recreational fisheries in lake‐rich landscapes with diverse fish communities and anglers alike presents a social and biological challenge for managers. Understanding angler preferences is central to navigating these challenges and can aid in predicting shifts in angler behavior in response to management actions or changing fish populations. Species‐specific angler surveys do not incorporate tradeoffs inherent in multispecies fisheries, thus limiting their application to real‐world management issues. To better understand angler preferences in relation to realistic tradeoffs among different fishing opportunities, we conducted a survey of Wisconsin anglers in 2013–2014 that included questions...
Managers of public lands in the western U.S. face enormous challenges under recent warmer, drier conditions that are expected to worsen. This enhanced aridity can lead to permanent degradation of wildlife habitat and ecological services upon which humans depend. To help managers confront these challenges, our project used a network of vegetation monitoring data that managers already collect from the ground and air (satellite imagery) with climate conditions to determine which types of habitat are vulnerable to drought and elevated temperatures, what habitat changes may occur, and where across the landscape these changes will be most pronounced. We employed new assessment tools to determine how soils, topography,...
Abstract (from ScienceDirect): Rarity and life history traits inform multiple dimensions of intrinsic risk to climate and environmental change and can help systematically identify at-risk species. We quantified relative geographic rarity (area of occupancy), climate niche breadth, and life history traits for 114 freshwater fishes, amphibians, and reptiles in the U.S. Pacific Northwest. Our approach leveraged presence-only, publicly available data and traits-based inference to evaluate area of occupancy, climate sensitivity (i.e., climate niche breadth), and a Rarity and Climate Sensitivity (RCS) index of all species across multiple geographic extents, grain sizes, and data types. The RCS index was relatively stable...
Abstract (from http://afs.tandfonline.com/doi/abs/10.1080/03632415.2016.1186016): Climate is a critical driver of many fish populations, assemblages, and aquatic communities. However, direct observational studies of climate change impacts on North American inland fishes are rare. In this synthesis, we (1) summarize climate trends that may influence North American inland fish populations and assemblages, (2) compile 31 peer-reviewed studies of documented climate change effects on North American inland fish populations and assemblages, and (3) highlight four case studies representing a variety of observed responses ranging from warmwater systems in the southwestern and southeastern United States to coldwater systems...
Abstract (from Canadian Science Publishing): We used redd count data from 88 bull trout (Salvelinus confluentus) populations in the upper Columbia River basin to quantify local and regional patterns in population dynamics, including adult abundance, long-term trend, and population synchrony. We further used this information to assess conservation risk of metapopulations using eight population dynamic metrics associated with persistence. Local population abundances were generally low (<20 redds annually) and the majority of trends were either stable (85%) or declining (13%). Evidence of synchrony among populations was apparent but not related to fluvial distance between streams. Variability in annual abundances was...
Abstract: We present a new, non-flux corrected AOGCM, GENMOM, that combines the GENESIS version 3 atmospheric GCM (Global Environmental and Ecological Simulation of Interactive Systems) and MOM2 (Modular Ocean Model version 2) nominally at T31 resolution. We evaluate GENMOM by comparison with reanalysis products (e.g., NCEP2) and three models used in the IPCC AR4 assessment. GENMOM produces a global temperature bias of 0.6 °C. Atmospheric features such as the jet stream structure and major semi-permanent sea level pressure centers are well simulated as is the mean planetary-scale wind structure that is needed to produce the correct position of stormtracks. Most ocean surface currents are reproduced except where...
Categories: Publication; Types: Citation; Tags: National CASC