Skip to main content
USGS - science for a changing world
Advanced Search

Filters: Categories: Publication (X) > Date Range: {"choice":"week"} (X)

69 results (55ms)   

Filters
Date Types (for Date Range)
Extensions
Types
Contacts
Categories
Tag Types
Tag Schemes
View Results as: JSON ATOM CSV
thumbnail
Arctic grayling (Thymallus arcticus) have a life-history strategy specifically adapted to the extreme climate of the North. These fish migrate to spawning grounds just after breakup in the spring, then migrate to feeding sites in early summer, and finally in the fall migrate back to their overwintering sites. The Kuparuk River is a perennial stream originating in the northern foothills of the Brooks Range on the North Slope of Alaska. Sections of the Kuparuk are periodically intermittent in that, during low flows in the system, these channel reaches appear dry. The flow varies between surface and subsurface in this permafrost-dominated environment, with subsurface flow being limited to the unfrozen thaw bulb around...
thumbnail
Watersheds draining the Arctic Coastal Plain (ACP) of Alaska are dominated by permafrostand snowmelt runoff that create abundant surface storage in the form of lakes, wetlands, and beaded streams. These surface water elements compose complex drainage networks that affect aquatic ecosystem connectivity and hydrologic behavior. The 4676 km2 Fishand Creek drainage basin is composed of three watersheds that represent a gradient of theACP landscape with varying extents of eolian, lacustrine, and fluvial landforms. In each watershed, we analyzed 2.5-m-resolution aerial photography, a 5-m digital elevationmodel, and river gauging and climate records to better understand ACP watershed structureand processes. We show that...
A genecological approach was used to explore genetic variation for survival in Artemisia tridentata (big sagebrush). Artemisia tridentata is a widespread and foundational shrub species in western North America. This species has become extremely fragmented, to the detriment of dependent wildlife, and efforts to restore it are now a land manage-ment priority. Common- garden experiments were established at three sites with seed-lings from 55 source- populations. Populations included each of the three predominant subspecies, and cytotype variations. Survival was monitored for 5 years to assess dif-ferences in survival between gardens and populations. We found evidence of adap-tive genetic variation for survival. Survival...
thumbnail
Drivers of environmental change in one location can have profound effects on ecosystem services and human well-being in distant locations, often across international borders. The telecoupling provides a conceptual framework for describing these interactions-for example, locations can be defined as sending areas (sources of flows of ecosystem services, energy, or information) or receiving areas (recipients of flows). However, the ability to quantify feedbacks between ecosystem change in one area and societal benefits in other areas requires analytical approaches. We use spatial subsidie-an approach developed to measure the degree to which a migratory species’ ability to provide services in one location depends on...
Categories: Publication; Types: Citation
thumbnail
There is a great deal of interest in whether and how Alaska’s precipitation is changing but little agreement in the existing peer-reviewed literature. To provide insight on this question, we have selected three commonly used 0.5° resolution gridded precipitation products that have long-term monthly data coverage (Climatic Research Unit TS3.10.1, Global Precipitation Climatology Centre Full Data Reanalysis version 5, and University of Delaware version 2.01) and evaluated their homogeneity and trends with multiple methods over two periods, 1950–2008 and 1980–2008. All three data sets displayed common broadscale features of Alaska’s precipitation climatology, but there were substantial differences between them in terms...
Bromus tectorum (cheatgrass) has widely invaded the Great Basin, U.S.A. The sporadic natural phenomenon of complete stand failure (‘die- off’) of this invader may present opportunities to restore native plants. A recent die-off in Nevada was precision-planted with seeds of the native grasses Poa secunda (Sandberg bluegrass) and Elymus elymoides (bottlebrush squirreltail), of both local and nonlocal origin, to ask: 1) Can native species be restored in recent B. tectorum die-offs? And 2) Do local and nonlocal seeds differ in performance? Additionally, we asked how litter removal and water addition affected responses. Although emergence and growth of native seeds was lower in die-off than control plots early in year...
Although biotic responses to contemporary climate change are spatially pervasive and often reflect synergies between climate and other ecological disturbances, the relative importance of climatic factors versus habitat extent for species persistence remains poorly understood. To address this shortcoming, we performed surveys for American pikas (Ochotona princeps) at > 910 locations in 3 geographic regions of western North America during 2014 and 2015, complementing earlier modern (1994–2013) and historical (1898–1990) surveys. We sought to compare extirpation rates and the relative importance of climatic factors versus habitat area for pikas in a mainland-versus-islands framework. In each region, we found widespread...
thumbnail
Floods, spatially complex water flows, and organism movements all generate important fluxes of aquatic-derived materials into terrestrial habitats, counteracting the gravity-driven downhill transport of matter from terrestrial-to-aquatic ecosystems. The magnitude of these aquatic subsidies isoften smaller than terrestrial subsidies to aquatic ecosystems but higher in nutritional quality, energy density, and nutrient concentration. The lateral extent of biological aquatic subsidies is typically small, extending only a few meters into riparian habitat; however, terrestrial consumers often aggregate on shorelines to capitalize on these high-quality resources. Although the ecological effects of aquatic subsidies remain...
thumbnail
How local geomorphic and hydrologic features mediate the sensitivity of stream thermal regimes to variation in climatic conditions remains a critical uncertainty in understanding aquatic ecosystem responses to climate change. We used stable isotopes of hydrogen and oxygen to estimate contributions of snow and rainfall to 80 boreal streams and show that differences in snow contribution are controlled by watershed topography. Time series analysis of stream thermal regimes revealed that streams in rain-dominated, low-elevation watersheds were 5–8 times more sensitive to variation in summer air temperature compared to streams draining steeper topography whose flows were dominated by snowmelt. This effect was more pronounced...
Rising temperatures have begun to shift flowering time, but it is unclear whether phenotypic plasticity canaccommodate projected temperature change for this century. Evaluating clines in phenological traits and the extentand variation in plasticity can provide key information on assessing risk of maladaptation and developing strategiesto mitigate climate change. In this study, flower phenology was examined in 52 populations of big sagebrush (Artemi-sia tridentata) growing in three common gardens. Flowering date (anthesis) varied 91 days from late July to lateNovember among gardens. Mixed-effects modeling explained 79% of variation in flowering date, of which 46% couldbe assigned to plasticity and genetic variation...
The loss of big sagebrush (Artemisia tridentata Nutt.) on sites disturbed by fire has motivated restoration seeding and planting efforts. However, the resulting sagebrush establishment is often lower than desired, especially in dry areas. Sagebrush establishment may be increased by addressing factors such as seed source and condition or management of the plant community. We assessed initial establishment of seeded sagebrush and four populations of small outplants (from different geographies, climates, and cytotypes) and small sagebrush outplants in an early seral community where mowing, herbicide, and seeding of other native plants had been experimentally applied. No emergence of seeded sagebrush was detected. Mowing...
Conservation Biology Institute (CBI) has been developing web applications to centralize and serve credible and usable information that allows natural resource managers, as well as the general public, to better understand the challenges posed by on-going environmental change. In particular CBI has designed a series of climate consoles that provide natural resource managers the most recent 5th Climate Model Intercomparison Program (CMIP5) climate projections, landscape intactness, and soil sensitivity for a series of reporting units over the western United States. The publically available web sites were refined based on feedback from a variety of users. In this paper, we describe each of the tools developed as open-source...
thumbnail
Interactions and feedbacks between abundant surface waters and permafrost fundamentally shapelowland Arctic landscapes. Sublake permafrost is maintained when the maximum ice thickness (MIT) exceedslake depth and mean annual bed temperatures (MABTs) remain below freezing. However, decliningMIT since the1970s is likely causing talik development below shallow lakes. Here we show high-temperature sensitivity towinter ice growth at the water-sediment interface of shallow lakes based on year-round lake sensor data.Empirical model experiments suggest that shallow (1m depth) lakes have warmed substantially over the last30years (2.4°C), withMABT above freezing5 of the last 7years.This is incomparison to slower ratesofwarming...
The tundra biome is the dominant terrestrial ecosystem of the circumpolar north, and its fate in a rapidly changing climate is of high scientific and socioeconomic concern. One of those concerns is that the majority of caribou herds throughout the circumpolar north are declining, perhaps as a result of climate change. The principal objective of this research is to reveal the connections between soil nutrient cycling, forage quality and caribou habitat selection. This framework is underpinned by the concept that tundra ecosystem productivity is ultimately driven by the thermodynamics of the system induced by climate.
thumbnail
In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lakesummer surface water temperatures rose rapidly (global mean = 0.34°C decade1) between 1985 and2009. Our analyses show that surface water warming rates are dependent on combinations of climate andlocal characteristics, rather than just lake location, leading to the counterintuitive result that regionalconsistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widelygeographically distributed, and their warming is associated with interactions among different climatic factors—from seasonally ice-covered lakes in areas where temperature and solar radiation are increasing whilecloud...
The phenomenon of cheatgrass die-off is a common and naturally- occurring stand failure that can eliminate the presence of this annual grass for a year or more, affecting tens to hundreds of thousands of acres in some years. We designed a study to determine if the temporary lack of cheatgrass caused by die-offs is a restoration opportunity. We seeded native perennial species at three die-offs in the Winnemucca, Nevada area. Native grass establishment in die-offs was almost three times higher in the first season at all sites, relative to adjacent areas without die-off. In the second season, establishment was five times higher in the die-off at two sites, and plants were notably larger in the die-off at the third...
thumbnail
Many Arctic shorebird populations are declining, and quantifying adult survival and the effects of anthropogenic factorsis a crucial step toward a better understanding of population dynamics. We used a recently developed, spatially explicitCormack–Jolly–Seber model in a Bayesian framework to obtain broad-scale estimates of true annual survival rates for 6species of shorebirds at 9 breeding sites across the North American Arctic in 2010–2014. We tested for effects ofenvironmental and ecological variables, study site, nest fate, and sex on annual survival rates of each species in thespatially explicit framework, which allowed us to distinguish between effects of variables on site fidelity versus truesurvival. Our...
thumbnail
The Arctic Coastal Plain (ACP) of Alaska is an important region for millions of migrating and nesting shorebirds. However, this region is threatened by climate change and increased human development (e.g., oil and gas production) that have the potential to greatly impact shorebird populations and breeding habitat in the near future. Because historic data on shorebird distributions in the ACP are very coarse and incomplete, we sought to develop detailed, contemporary distribution maps so that the potential impacts of climate-mediated changes and development could be ascertained. To do this, we developed and mapped habitat suitability indices for eight species of shorebirds (Black-bellied Plover [Pluvialis squatarola],...
Abstract (from PLOS One): Declining natural resources have led to a cultural renaissance across the Pacific that seeks to revive customary ridge-to-reef management approaches to protect freshwater and restore abundant coral reef fisheries. Effective ridge-to-reef management requires improved understanding of land-sea linkages and decision-support tools to simultaneously evaluate the effects of terrestrial and marine drivers on coral reefs, mediated by anthropogenic activities. Although a few applications have linked the effects of land cover to coral reefs, these are too coarse in resolution to inform watershed-scale management for Pacific Islands. To address this gap, we developed a novel linked land-sea modeling...
Categories: Publication; Types: Citation
The Adapt Alaska Collaborative grew out of a set of initiatives to promote climate resilience and adaptation in Alaska. On May 24 and 25, 2017 a group of participants (including representatives of Alaska regional, state and federal agencies and organizations) gathered at a work session to identify next steps to build on the momentum generated by these initiatives toward a more resilient Alaska. At the work session, three working groups formed around specific areas of effort, including a Planning Working Group with the task of identifying ways to streamline the many planning requirements associated with implementing climate resilience and adaptation strategies.The Adapt Alaska Planning Working Group looked at a range...


map background search result map search result map Linking North Slope of Alaska climate, hydrology, and fish migration Environmental and ecological conditions at Arctic breeding sites have limited effects on true survival rates of adult shorebirds Threshold sensitivity of shallow Arctic lakes and sublake permafrost to changing winter climate Reconciling precipitation trends in Alaska: 2. Gridded data analyses Rapid and highly variable warming of lake surface waters around the globe Watershed geomorphology and snowmelt control stream thermal sensitivity to air temperature Subsidies of Aquatic Resources in Terrestrial Ecosystems Predicting breeding shorebird distributions on the Arctic Coastal Plain of Alaska Drainage Network Structure and Hydrologic Behavior of Three Lake-Rich Watersheds on the Arctic Coastal Plain, Alaska Linking North Slope of Alaska climate, hydrology, and fish migration Threshold sensitivity of shallow Arctic lakes and sublake permafrost to changing winter climate Drainage Network Structure and Hydrologic Behavior of Three Lake-Rich Watersheds on the Arctic Coastal Plain, Alaska Rapid and highly variable warming of lake surface waters around the globe Watershed geomorphology and snowmelt control stream thermal sensitivity to air temperature Subsidies of Aquatic Resources in Terrestrial Ecosystems Predicting breeding shorebird distributions on the Arctic Coastal Plain of Alaska Reconciling precipitation trends in Alaska: 2. Gridded data analyses Environmental and ecological conditions at Arctic breeding sites have limited effects on true survival rates of adult shorebirds