Skip to main content
Advanced Search

Filters: Tags: tundra (X)

12 results (53ms)   

Filters
Date Range
Extensions
Types
Contacts
Categories
Tag Types
Tag Schemes
View Results as: JSON ATOM CSV
We investigated experimental warming and simulated grazing (clipping) effects on rangeland quality, as indicated by vegetation production and nutritive quality, in winter-grazed meadows and summer-grazed shrublands on the Tibetan Plateau, a rangeland system experiencing climatic and pastoral land use changes. Warming decreased total aboveground net primary productivity (ANPP) by 40 g.m?�.yr?� at the meadow habitats and decreased palatable ANPP (total ANPP minus non-palatable forb ANPP) by 10 g.m?�.yr?� at both habitats. The decreased production of the medicinal forb Gentiana straminea and the increased production of the non-palatable forb Stellera chamaejasme with warming also reduced rangeland quality. At the shrubland...
The global mean surface temperature increased 0.85°C during the period 1880 – 2012. Some climate models predict an additional warming of up 2 to 4 ◦ C over the next 100 years for the primary breeding grounds for North American ducks. Such an increase has been predicted to reduce mid - continent breeding duck populations by >70%. Managing continental duck populations in the face of climate change requires understanding how waterfowl have responded to historical spatio - temporal climatic variation. However, such responses to climate may be obscured by how ducks respond to variation in land cover. We estimated effects of climate on settlement patterns of breeding ducks in the Prairie - Parkland Region (PPR), boreal...
thumbnail
Conclusions: Caribou demonstrated patterns of avoidance near linear features such as pipelines, roads, and other oil field structures. Females demonstrated heightened avoidance, especially during calving seasons. Thresholds/Learnings: Synopsis: This study documented the behavioural reactions of caribou to oil development in the circumpolar regions of the northern hemisphere. Researchers observed patterns of avoidance near linear features such as pipelines, roads, and other oil field structures. Female caribou, especially those accompanied by calves avoided these areas in particular. Male caribou were more apt to occupy areas influenced by oil field structures and activity. In summary, the patterns oil field development...
Shrubs have increased in abundance and dominance in arctic and alpine regions in recent decades. This often dramatic change, likely due to climate warming, has the potential to alter both the structure and function of tundra ecosystems. The analysis of shrub growth is improving our understanding of tundra vegetation dynamics and environmental changes. However, dendrochronological methods developed for trees, need to be adapted for the morphology and growth eccentricity of shrubs. Here, we review current and developing methods to measure radial and axial growth, estimate age, and assess growth dynamics in relation to environmental variables. Recent advances in sampling methods, analysis and applications have improved...
thumbnail
This map shows the Alpine Dwarf Shrub Tundra conservation element data in the CYR study area. Layers include: Distribution map of the alpine dwarf shrub tundra CE; Current, near-term, and long-term status of alpine dwarf shrub tundra in the CYR study area. These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. These data may not have the accuracy, resolution, completeness, timeliness, or other characteristics appropriate for applications that potential users of the data may contemplate. The User...
Shrubs have increased in abundance and dominance in arctic and alpine regions in recent decades. This often dramatic change, likely due to climate warming, has the potential to alter both the structure and function of tundra ecosystems. The analysis of shrub growth is improving our understanding of tundra vegetation dynamics and environmental changes. However, dendrochronological methods developed for trees, need to be adapted for the morphology and growth eccentricity of shrubs. Here, we review current and developing methods to measure radial and axial growth, estimate age, and assess growth dynamics in relation to environmental variables. Recent advances in sampling methods, analysis and applications have improved...
thumbnail
This map shows the Alpine and Arctic Tussock Tundra conservation element data in the CYR study area. Layers include: Distribution map of the alpine and Arctic tussock tundra CE; Summer Warmth Index for alpine dwarf shrub tundra and alpine and Arctic tussock tundra for the current condition and long-term future; Current, near-term, and long-term status of alpine and Arctic tussock tundra in the CYR study area. These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. These data may not have the accuracy,...
To assess the North American high-latitude vegetation response to the rising temperature, we derived NDVI trend for 91.2% of the non-water, non-snow land area of Canada and Alaska using the peak-summer Landsat surface reflectance data of 1984–2012. Our analysis indicated that 29.4% and 2.9% of the land area of Canada and Alaska showed statistically significant positive (greening) and negative (browning) trends respectively, at significance level p < 0.01, after burned forest areas were masked out. The area with greening trend dominated over that with browning trend for all land cover types. The greening occurred primarily in the tundra of western Alaska, along the north coast of Canada and in northeastern Canada;...
thumbnail
Changes in Arctic coastal ecosystems in response to global warming may be some of the most severe on the planet. A better understanding and analysis of the rates at which these changes are expected to occur over the coming decades is crucial in order to delineate high-priority areas that are likely to be affected by climate changes. The data provided in this release are part of a study that assessed the likelihood of changes to a barrier island – lagoon systems in response to projected changes in atmospheric and oceanographic forcing associated with Arctic warming. Arey Lagoon and the surrounding area near Barter Island, Alaska, were focused upon as part of this pilot study. The study investigates the dominance...
To assess the North American high-latitude vegetation response to the rising temperature, we derived NDVI trend for 91.2% of the non-water, non-snow land area of Canada and Alaska using the peak-summer Landsat surface reflectance data of 1984–2012. Our analysis indicated that 29.4% and 2.9% of the land area of Canada and Alaska showed statistically significant positive (greening) and negative (browning) trends respectively, at significance level p < 0.01, after burned forest areas were masked out. The area with greening trend dominated over that with browning trend for all land cover types. The greening occurred primarily in the tundra of western Alaska, along the north coast of Canada and in northeastern Canada;...
Understanding of the organic layer thickness (OLT) and organic layer carbon (OLC) stocks in subarctic ecosystems is critical due to their importance in the global carbon cycle. Moreover, post-fire OLT provides an indicator of long-term successional trajectories and permafrost susceptibility to thaw. To these ends, we 1) mapped OLT and associated uncertainty at 30 m resolution in the Yukon River Basin (YRB), Alaska, employing decision tree models linking remotely sensed imagery with field and ancillary data, 2) converted OLT to OLC using a non-linear regression, 3) evaluate landscape controls on OLT and OLC, and 4) quantified the post-fire recovery of OLT and OLC. Areas of shallow (< 10 cm), moderate (≥ 10 cm and...
    map background search result map search result map Caribou in the Changing North Surficial geology of the Dalton Highway (Itkillik-Sagavanirktok rivers) area, southern Arctic foothills, Alaska Modeled 21st century storm surge, waves, and coastal flood hazards and supporting oceanographic and geological field data (2010 and 2011) for Arey and Barter Islands, Alaska and vicinity BLM REA CYR 2013 Alpine and Arctic Tussock Tundra BLM REA CYR 2013 Alpine Dwarf Shrub Tundra Modeled 21st century storm surge, waves, and coastal flood hazards and supporting oceanographic and geological field data (2010 and 2011) for Arey and Barter Islands, Alaska and vicinity Surficial geology of the Dalton Highway (Itkillik-Sagavanirktok rivers) area, southern Arctic foothills, Alaska BLM REA CYR 2013 Alpine and Arctic Tussock Tundra BLM REA CYR 2013 Alpine Dwarf Shrub Tundra Caribou in the Changing North