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At least 1,423 records · Page 79Linked to original sources

Flood resilience in paired US–Mexico border cities: A study of binational risk perceptions

Disastrous floods in the twin cities of Nogales, Arizona, USA, and Nogales, Sonora, Mexico (collectively referred to as Ambos Nogales) occur annually in response to monsoonal summer rains. Flood-related hazards include property damage, impairment to sewage systems, sewage discharge, water contamination, erosion, and loss of life. Flood risk, particularly in Nogales, Sonora, is amplified by informal, “squatter” settlements in the watershed floodplain and associated development and infrastructure. The expected increase in precipitation intensity, resulting from climate change, poses further risk to flooding therein. We explore binational community perceptions of flooding, preferences for watershed management, and potential actions to address flooding and increase socio-ecological resilience in Ambos Nogales using standardized questionnaires and interviews to collect data about people and their preferences. We conducted 25 semi-structured interviews with local subject matter experts and gathered survey responses from community members in Ambos Nogales. Though survey response was limited, expected frequencies were high enough to conduct Chi-squared tests of independence to test for statistically significant relationships between survey variables. Results showed that respondents with previous experience with flooding corresponded with their level of concern about future floods. Additionally, respondents perceived greater flood-related risks from traveling across town and damage to vehicles than from inundation or damages to their homes or neighborhoods. Binationally, women respondents felt less prepared for future floods than men. On both sides of the border, community members and local experts agreed that Ambos Nogales lacks adequate preparation for future floods. To increase preparedness, they recommended flood risk education and awareness campaigns, implementation of green infrastructure, additional stormwater infrastructure (such as drainage systems), enhanced flood early warning systems, and reduction of flood flows through regulations to reduce the expansion of hard surfaces. This study contributes systematic collection of information about flood risk perceptions across an international border, including novel data regarding risks related to climate change and gender-based assessments of flood risk. Our finding of commonalities across both border communities, in perceptions of flood risk and in the types of risk reduction solutions recommended by community members, provides clear directions for flood risk education, outreach, and preparedness, as well as measures to enhance cross-border cooperation.

Arizona, Sonora↗

Modeled streamflow response to scenarios of Tundra Lake water withdrawal and seasonal climate extremes, Arctic Coastal Plain, Alaska

On the Arctic Coastal Plain (ACP) in Northern Alaska (USA), permafrost and abundant surface-water storage define watershed hydrological processes, which are increasingly subject to changes both in climate and land-use. In the last decades, the ACP landscape experienced extreme climate events and increased lake water withdrawal (LWW) for construction of infrastructure related to resource extraction (primarily ice roads and industrial operations). However, their potential (combined) effects on streamflow are relatively underexplored. Here, we applied the process-based, spatially distributed hydrological and thermal Water Balance Simulation Model (WaSiM) (10 m spatial resolution) to the 30 km² Crea Creek watershed located on the ACP. The impacts of documented seasonal climate extremes and LWW were evaluated on seasonal runoff (May-August), including minimum 7-day mean flow (MQ7), the recovery time of MQ7 to pre-perturbation conditions and the duration of streamflow conditions that prevents fish passage. Low-rainfall scenarios (21% of normal, 1 to 3 summers in a row) caused a larger reduction in MQ7 (56 - 69%) than LWW alone (44 - 58%). Decadal-long consecutive LWW resulted in a new equilibrium in low-flow and seasonal runoff after the third year of LWW that included a disconnected stream network, a reduced contributing area (54% of the watershed area) and limited fish passage throughout summer. Our results highlight that LWW is not offset by same-year snowmelt for lake water levels and streamflow as currently assumed in land management regulations. Effective land management would therefore benefit from considering the combined impact of climate change and industrial lake water withdrawals.

Alaska↗

Climate change in the federated states of Micronesia: Food and water security, climate risk management, and adaptive strategies

This is a report of findings following research and a three-week field assessment (April 2009) of the Federated States of Micronesia (FSM) in response to nation-wide marine inundation by extreme tides (December 2007, September 2008, December 2008).3 The study was conducted at the request of the US Department of Agriculture Forest Service and the state and federal governments of FSM.

Report↗

Quantifying the response of nitrogen speciation to hydrology in the Chesapeake Bay Watershed using a multilevel modeling approach

Excessive nitrogen (N) inputs to coastal waters can lead to severe eutrophication and different chemical forms of N exhibit varying levels of effectiveness in fueling primary production. Efforts to mitigate N fluxes from coastal watersheds are often guided by models that predict changes in N loads as a function of changes in land use, management practices, and climate. However, relatively little is known on the impacts of such changes on the relative fractions of different N forms. We leveraged a long-term dataset of N loads from over 100 river stations to investigate how the fraction, that is, the ratio of to total N ( /TN), changes as a function of spatio-temporal changes in TN loads in the Chesapeake Bay watershed. We built a hierarchical model that separates the response of to changes in TN load occurring at different scales: Across river stations, where differences in TN loads are largely driven by spatial differences in anthropogenic inputs, and within stations, where inter-annual variability in hydrology is a key driver of changes in TN loads. Results suggest that while increases in TN loads resulting from changes in anthropogenic inputs lead to an increase in the fraction, a decrease in the fraction may occur when increases in TN loads are driven by increased streamflow. These results are especially relevant in watersheds that may experience changes in N loads due to both management decisions and climate-driven changes in hydrology.

Chesapeake Bay watershed↗

Response of Everglades tree islands to environmental change

Tree islands are centers of biodiversity within the Florida Everglades, USA, but the factors controlling their distribution, formation, and development are poorly understood. We use pollen assemblages from tree islands throughout the greater Everglades ecosystem to reconstruct the timing of tree island formation, patterns of development, and response to specific climatic and environmental stressors. These data indicate that fixed (teardrop-shaped) and strand tree islands developed well before substantial human alteration of the system, with initial tree island vegetation in place between 3500 and 500 calibrated years before present (cal yr BP), depending on the location in the Everglades wetland. Tree island development appears to have been triggered by regional- to global-scale climatic events at 2800 cal yr BP, 1600–1500 cal yr BP, 1200–1000 cal yr BP (early Medieval Warm Period), and 500–200 cal yr BP (Little Ice Age). These periods correspond to drought intervals documented in Central and South America and periods of southward displacement of the Intertropical Convergence Zone. The records indicate a coherence of climate patterns in both subtropical North America and the Northern Hemisphere Neotropics. Water management practices of the 20th century altered plant communities and size of tree islands throughout the Everglades. Responses range from loss of tree islands due to artificially long hydroperiods and deep water to expansion of tree islands after flow reductions. These data provide evidence for the rapidity of tree island response to specific hydrologic change and facilitate prediction of the response to future changes associated with Everglades restoration plans.

Florida↗

Consolidation drainage and climate change may reduce Piping Plover habitat in the Great Plains

Many waterbird species utilize a diversity of aquatic habitats; however, with increasing anthropogenic needs to manage water regimes there is global concern over impacts to waterbird populations. The federally threatened Piping Plover (Charadrius melodus; hereafter plovers) is a shorebird that breeds in three habitat types in the Prairie Pothole Region of North Dakota, South Dakota, and Canada: riverine sandbars; reservoir shorelines; and prairie wetlands. Water surface areas of these habitats fluctuate in response to wet-dry periods; decreasing water surface areas expose shorelines that plovers utilize for nesting. Climate varies across the region so when other habitats are unavailable for plover nesting because of flooding, prairie wetlands may periodically provide habitat. Over the last century, many of the wetlands used by plovers in the Prairie Pothole Region have been modified to receive water from consolidation drainage (drainage of smaller wetlands into another wetland), which could eliminate shoreline nesting habitat. We evaluated whether consolidation drainage and fuller wetlands have decreased plover presence in 32 wetlands historically used by plovers. We found that wetlands with more consolidation drainage in their catchment and wetlands that were fuller had a lower probability of plover presence. These results suggest that plovers could have historically used prairie wetlands during the breeding season but consolidation drainage and/or climate change have reduced available shoreline habitat for plovers through increased water levels. Prairie wetlands, outside of some alkali wetlands in the western portion of the region, are less studied as habitat for plovers when compared to river and reservoir shorelines. Our study suggests that these wetlands may have played a larger role in plover ecology than previously thought. Wetland restoration and conservation, through the restoration of natural hydrology, may be required to ensure that adequate habitat exists among the three habitat types in the face of existing or changing climate and to ensure long-term conservation.

North Dakota↗

Recent changes in annual area burned in interior Alaska: The impact of fire management

The Alaskan boreal forest is characterized by frequent extensive wildfires whose spatial extent has been mapped for the past 70 years. Simple predictions based on this record indicate that area burned will increase as a response to climate warming in Alaska. However, two additional factors have affected the area burned in this time record: the Pacific decadal oscillation (PDO) switched from cool and moist to warm and dry in the late 1970s and the Alaska Fire Service instituted a fire suppression policy in the late 1980s. In this paper a geographic information system (GIS) is used in combination with statistical analyses to reevaluate the changes in area burned through time in Alaska considering both the influence of the PDO and fire management. The authors found that the area burned has increased since the PDO switch and that fire management drastically decreased the area burned in highly suppressed zones. However, the temporal analysis of this study shows that the area burned is increasing more rapidly in suppressed zones than in the unsuppressed zone since the late 1980s. These results indicate that fire policies as well as regional climate patterns are important as large-scale controls on fires over time and across the Alaskan boreal forest.

Alaska↗

U.S. Geological Survey activities related to American Indians and Alaska Natives: Fiscal years 2009 and 2010

The U.S. Geological Survey is the earth and natural science bureau within the U.S. Department of the Interior. The U.S. Geological Survey provides impartial information on the health of our ecosystems and environment, the natural hazards that threaten us, the natural resources we rely on, the negative effects of climate and land-use change, and the core science systems that help us provide timely, relevant, and usable information. The U.S. Geological Survey is not responsible for regulations or land management. In the late 1800s, John Wesley Powell the second director of the U.S. Geological Survey, followed his interest in the Tribes of the Great Basin and Colorado Plateau and studied their cultures, languages, and surroundings. From that early time, the U.S. Geological Survey has recognized the importance of Native knowledge as a complement to the U.S. Geological Survey mission to better understand the Earth and its systems. Collaboration allows the U.S. Geological Survey and Native American governments, organizations, and peoples to increase their mutual understanding of the increasing challenges facing our natural world. Although this report uses the term “resources,” the U.S. Geological Survey, through its interdisciplinary research, acknowledges the interconnectedness of the Earth and all the life forms that live upon it.

Circular↗

The U.S. Geological Survey Land Remote Sensing Program

The fundamental goals of the U.S. Geological Survey's Land Remote Sens-ing (LRS) Program are to provide the Federal Government and the public with a primary source of remotely sensed data and applications and to be a leader in defining the future of land remote sensing, nationally and internationally. Remotely sensed data provide information that enhance the understand-ing of ecosystems and the capabilities for predicting ecosystem change. The data promote an understanding of the role of the environment and wildlife in human health issues, the requirements for disaster response, the effects of climate variability, and the availability of energy and mineral resources. Also, as land satellite systems acquire global coverage, the program coordinates a network of international receiving stations and users of the data. It is the responsibility of the program to assure that data from land imaging satellites, airborne photography, radar, and other technologies are available to the national and global science communities.

Fact Sheet↗

Precipitation-runoff modeling system; user's manual

The concepts, structure, theoretical development, and data requirements of the precipitation-runoff modeling system (PRMS) are described. The precipitation-runoff modeling system is a modular-design, deterministic, distributed-parameter modeling system developed to evaluate the impacts of various combinations of precipitation, climate, and land use on streamflow, sediment yields, and general basin hydrology. Basin response to normal and extreme rainfall and snowmelt can be simulated to evaluate changes in water balance relationships, flow regimes, flood peaks and volumes, soil-water relationships, sediment yields, and groundwater recharge. Parameter-optimization and sensitivity analysis capabilites are provided to fit selected model parameters and evaluate their individual and joint effects on model output. The modular design provides a flexible framework for continued model system enhancement and hydrologic modeling research and development. (Author 's abstract)

Water-Resources Investigations Report↗

Predicting the effects of climate change on ecosystems and wildlife habitat in northwest Alaska

We used a modeling framework and a recent ecological land classification and land cover map to predict how ecosystems and wildlife habitat in northwest Alaska might change in response to increasing temperature. Our results suggest modest increases in forest and tall shrub ecotypes in Northwest Alaska by the end of this century thereby increasing habitat for forest-dwelling and shrub-using birds and mammals. Conversely, we predict declines in several more open low shrub, tussock, and meadow ecotypes favored by many waterbird, shorebird, and small mammal species.

Alaska↗

Managing native and non-native sea lamprey ( Petromyzon marinus ) through anthropogenic change: A prospective assessment of key threats and uncertainties

Sea lamprey ( Petromyzon marinus ) is a species of conservation concern in their native range of the Atlantic coasts of Europe (Near Threatened to Critically Endangered) and North America (Secure to Critically Imperiled), and an invasive species of great economic and ecological concern in the Laurentian Great Lakes. Despite differences in life history strategy (anadromous natives vs adfluvial non-natives), the biology of sea lamprey is sufficiently similar to expect comparable responses to large-scale environmental change. We take a prospective look at the future (50 to 100 years) of sea lamprey management in an era of considerable environmental disturbance, and consider biological responses, management actions, and the future status of populations across the native and non-native ranges. Based on facilitated discussion by a diverse group of international experts, two major but poorly characterized classes of threats to sea lamprey were identified: climate change and socio-political issues. We discuss how climate induced changes affect growth, bioenergetics, and phenology of sea lamprey, and associated effects on control tactics (pesticides and barriers) and conservation. We consider tensions surrounding improving connectivity in the Great Lakes while controlling invasive sea lamprey, and discuss supplements and alternatives to pesticides and their wider effect, as well as the effects of new invasive species. To prevent the extirpation of native sea lamprey populations, or the re-expansion of non-native populations, we conclude with a call for new and ongoing dialogue and collaboration among all sea lamprey biologists and managers across the native and non-native range.

Journal of Great Lakes Research↗

Ecosystem implications of conserving endemic versus eradicating introduced large herbivores in the Galapagos Archipelago

Restoration of damaged ecosystems through invasive species removal and native species conservation is an increasingly common practice in biodiversity conservation. Estimating the degree of ecosystem response attributable specifically to eradication of exotic herbivores versus restoration of native herbivores is often difficult and is complicated by concurrent temporal changes in other factors, especially climate. We investigated the interactive impacts of native mega-herbivores (giant tortoises) and the eradication of large alien herbivores (goats) on vegetation productivity across the Galapagos Archipelago. We examined archipelago-wide patterns of Normalized Difference Vegetation Index (NDVI) as a proxy for vegetation productivity between 2001 and 2015 and evaluated how goat and historical and current tortoise occurrence influenced productivity. We used a breakpoint analysis to detect change in trends in productivity from five targeted areas following goat eradication. We found a positive association between tortoise occurrence and vegetation productivity and a negative association with goat occurrence. We also documented an increase in plant productivity following goat removal with recovery higher in moister regions than in arid region, potentially indicating an alternate stable state has been created in the latter. Climate variation also contributed to the detected improvement in productivity following goat eradication, sometimes obscuring the effect of eradication but more usually magnifying it by up to 300%. Our work offers perspectives regarding the effectiveness and outcomes of eradicating introduced herbivores and re-introducing native herbivores, and the merits of staging them simultaneously in order to restore critical ecosystem processes such as vegetation productivity.

Galapagos Islands↗

Thinking outside the rocks: Subsurface water storage, topography, and land cover are key modulators of large-scale riverine dissolved silicon dynamics

Riverine dissolved silicon (DSi) dynamics reflect integrated geologic, hydrologic, climatic, and ecological controls. We compiled annual DSi data for 337 rivers across four continents and trained interpretable machine-learning models to predict concentrations and yields from 28 watershed variables. Both models reproduced testing data ( R 2 = 0.85 for concentration and 0.96 for yield) and withheld-site validation ( R 2 = 0.91 and 0.93). Lithology, especially volcanic rock fraction, strongly controlled DSi while subsurface storage, topography, and land cover further shaped DSi dynamics. DSi concentrations and yields exhibited nonlinear responses to basin slope, recession-curve slope, proportion of open-water cover, and nutrient availability. Concentrations showed sharper threshold responses to hydrologic and biotic variables, whereas yields varied more gradually with climate and lithology. These results provide a framework for forecasting DSi under land cover and climate change and for embedding realistic, nonlinear processes in mechanistic models.

Geophysical Research Letters↗

National wildlife refuge visitor survey results: 2010/2011

The U.S. Fish and Wildlife Service (Service) collaborated with the U.S. Geological Survey to conduct a national survey of visitors regarding their experiences on national wildlife refuges. The survey was conducted to better understand visitor needs and experiences and to design programs and facilities that respond to those needs. The survey results will inform Service performance planning, budget, and communications goals. Results will also inform Comprehensive Conservation Plan (CCPs), Visitor Services, and Transportation Planning processes. The survey was conducted on 53 refuges across the National Wildlife Refuge System (Refuge System) to better understand visitor needs and experiences and to design programs and facilities that respond to those needs. A total of 14,832 visitors agreed to participate in the survey between July 2010 and November 2011. In all, 10,233 visitors completed the survey for a 71% response rate. This report provides a summary of visitor and trip characteristics; visitor opinions about refuges and their offerings; and visitor opinions about alternative transportation and climate change, two Refuge System topics of interest. The Refuge System, established in 1903 and managed by the Service, is the leading network of protected lands and waters in the world dedicated to the conservation of fish, wildlife and their habitats. There are 556 National Wildlife Refuges and 38 wetland management districts nationwide, encompassing more than 150 million acres. The Refuge System attracts more than 45 million visitors annually, including 25 million people per year to observe and photograph wildlife, over 9 million to hunt and fish, and more than 10 million to participate in educational and interpretation programs. Understanding visitors and characterizing their experiences on national wildlife refuges are critical elements of managing these lands and meeting the goals of the Refuge System. These combined results are based on surveying at 53 participating refuges during 2010/2011 and contain the following information: * Synopsis: Brief summary of the survey results. * Introduction: An overview of the Refuge System and the goals of the national surveying effort. * Methods: The procedures for the national surveying effort, including selecting refuges, developing the survey instrument, contacting visitors, and guidance for interpreting the results. * Survey Results: Key findings from the survey, including: - Visitor and trip characteristics - Visitors opinions about refuges - Visitor opinions about alternative transportation - Visitor opinions about climate change * Conclusion * References Individual results for each of the 53 participating refuges are available at http://pubs.usgs.gov/ds/643/ as part of USGS Data Series 643.

Data Series↗

Approaches for using CMIP projections in climate model ensembles to address the ‘hot model’ problem

Several recent generation global-climate models were found to have anomalously high climate sensitivities and may not be useful for certain applications. Four approaches for developing ensembles of climate projections for applications that address this issue are: Using an “all models” approach; Screening using equilibrium climate sensitivity and (or) transient climate response; Bayesian model averaging; and Using global warming levels. Advantages and disadvantages of each approach are described by using example applications to study the effects of climate change on an imaginary at-risk species. Choosing the right approach is dependent on the location, goals, and system focus of each application and the risk-tolerance and resource-management context.

Open-File Report↗

Assessing risk for enhanced cyanobacteria, phytoplankton, and pathogens with changes in water level regime with potential application to Lake Powell and Lake Mead: A mixed methods literature review

Water levels in freshwater reservoirs worldwide are changing due to altered climate, management practices, and increasing human demand for water. In the desert southwestern USA, managers are considering significant changes to reservoir operation strategies and water management in response to consumptive use and ongoing drought. To inform reservoir management decision-making, we reviewed current peer-reviewed literature to identify the effects of decreasing or increasing water level on phytoplankton, cyanobacteria, Escherichia coli , and Naegleria spp. We identified 34 studies containing 42 individual waterbodies that investigated the effects of water level increases or decreases on phytoplankton or cyanobacteria. We found that water level decreases resulted in a higher likelihood of increased cyanobacteria, and that phytoplankton were more likely to decrease in response to water level increases. Most of the waterbodies included in the literature review were eutrophic or hypereutrophic, underscoring the need to explore the effects of water level fluctuations on oligotrophic systems. We only identified five studies on E. coli through our review, and no studies on Naegleria spp. We supplemented our review with regional white papers and case studies within the Colorado River Basin and the Rio Grande River Basin to highlight relevant research. Prior and ongoing research highlights the need to explore impacts of water level fluctuations on phytoplankton and cyanobacteria to guide future management decision-making.

Arizona, Utah, Nevada↗

Hydrological regime and climate interactively shape riparian vegetation composition along the Colorado River, Grand Canyon

Question How closely do riparian plant communities track hydrological and climatic variation in space, and how do interactions among hydrological and climatic filters influence success of flow management strategies? Location Grand Canyon, Arizona, USA. Methods Multi‐year vegetation surveys were conducted across three hydrological zones – active channel, active floodplain and inactive floodplain – within each of 42 sandbars that vary geographically in temperature and precipitation along a 400‐km river segment. Ecological niche models were used to estimate locally optimal conditions of maximum inundation duration, elevation above daily peak flow, mean annual precipitation, and mean maximum and minimum temperature for 16 of the most abundant woody and 58 most abundant herbaceous plant species. These estimates were used to calculate community‐weighted mean (CWM) environmental preferences, which were used to determine how closely vegetation preferences tracked local variation in environmental factors, and to assess interactive responses of species and communities to variation in hydrology and climate. Results Communities closely tracked hydrological variation across zones, but less so within zones. Communities tracked variation in minimum temperature more closely than maximum temperature or precipitation. At the species level, woody plants that were more abundant in wetter hydrological conditions were also more abundant in wetter climatic conditions, and vice versa. This relationship was even stronger at the community level, where there were significant negative relationships between CWM preferences of inundation duration and temperature for both woody and herbaceous vegetation. Conclusions The climate‐hydrology linkages found in this system suggest that increasing temperatures and drought are likely to reduce the inundation tolerance of riparian vegetation within the Grand Canyon. Increasing the duration of high flow events would likely reduce the abundance of encroaching woody vegetation, but could also reduce the resilience of remaining vegetation to heat waves and drought. The reinforcing effects of climatic and hydrological filters are likely to generally result in greater sensitivity of species composition to environmental change than if those environmental filters acted independently. These results have implications for predicting resource responses to environmental change, as well as prescriptions for direct vegetation management to enhance resilience.

Colorado River, Grand Canyon↗