Filters: Tags: boreal forest (X)
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Fire can be a significant driver of permafrost change in boreal landscapes, altering the availability of soil carbon and nutrients that have important implications for future climate and ecological succession. However, not all landscapes are equally susceptible to fire-induced change. As fire frequency is expected to increase in the high latitudes, methods to understand the vulnerability and resilience of different landscapes to permafrost degradation are needed. We present a combination of multiscale remote sensing, geophysical, and field observations that reveal details of both near-surface (<1 m) and deeper (>1 m) impacts of fire on permafrost. Along 11 transects that span burned-unburned boundaries in different...
Categories: Project;
Types: Journal Citation;
Tags: Boreal forest,
Disturbance,
Fire,
Nonuniform permafrost degradation,
Permafrost
Data were compiled on the seed production of white spruce in order to assess the long-term trends in seed production over the past 60 years in North American boreal forests. Data on cone production was merged with annual weather, teleconnection indices such as ENSO, and historical fires in boreal forests.
Biome-wide forest cover loss hotspot maps were created using annual MODIS imagery from 2000 to 2005. The regression tree algorithm related forest cover loss training data to the MODIS inputs, resulting in a per pixel 5-year change fraction map. We applied a 5% change fraction threshold to produce a per pixel forest change hotspot map. These data represent areas of intensive forest cover clearing. MODIS data alone are inadequate for accurate change area estimation because most forest clearing occurs at sub-MODIS pixel scales. For forest cover and forest cover loss area calculation please use the calibrated products at 18.5 km resolution. Data is in ESRI GRID format.
Chronic industrial noise affects pairing success and age structure of ovenbirds Seiurus aurocapilla.
Conclusions: There was a significant reduction in ovenbird pairing success at compressor sites (77%) compared with noiseless wellpads (92%). These differences were apparent regardless of territory quality or individual male quality. Noise interferes with a male's song, such that females may not hear the male's song at greater distances and/or females may perceive males to be of lower quality because of distortion of song characteristics Thresholds/Learnings: Synopsis: Anthropogenic noise is rapidly increasing in wilderness areas as a result of industrial expansion. This study assessed pairing success and age distribution of male ovenbirds, Seiurus aurocapilla, in the boreal forest of Alberta, Canada, in areas around...
Categories: Publication;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Land use configuration,
Landscape fragmentation,
Northern Alberta,
age structure,
birds,
Herbivores have the capacity to modify plant community composition and ecosystem structure and function via browsing. For example, moose and snowshoe hare facilitate succession in Alaska’s boreal forest by preferentially browsing early successional species over late successional conifers. Snowshoe hares also eat conifers, including white spruce, and this browsing may affect the pattern of spruce establishment over time. We measured over 800 spruce at 18 locations along the Tanana River floodplain in interior Alaska, USA and demonstrated that the proportion of spruce browsed annually positively correlates with annual hare abundance. Nearly all seedlings sampled had been browsed. Further, we modeled the pattern of...
Categories: Data,
Publication;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Alaska,
Boreal forest,
Herbivory,
Snowshoe hare,
Succession,
(le français suit)These spatial data are the basis for the paper written by J.P. Brandt entitled "The extent of the North American boreal zone" and related map published in the journal Environmental Reviews (17: 101-161, 2009). The circumpolar boreal zone is one of the world's major biogeoclimatic zones, covering much of North America and Eurasia with forests, woodlands, wetlands, and lakes. It regulates climate, acts as a reservoir for biological and genetic diversity, plays a key role in biogeochemical cycles, and provides renewable resources, habitat, and recreational opportunities. Poor agreement exists amongst scientists regarding this zone's delimitation and the areal extent of boreal forests, even though...
Spatial patterns in carbon (C) and nitrogen (N) cycles of high-latitude catchments have been linked to climate and permafrost, and used to infer potential changes in biogeochemical cycles under climate warming. However, inconsistent spatial patterns across regions indicate that factors in addition to permafrost and regional climate may shape responses of C and N cycles to climate change. We hypothesized that physical attributes of catchments modify responses of C and N cycles to climate and permafrost. We measured dissolved organic C (DOC) and nitrate (NO3–) concentrations, and composition of dissolved organic matter (DOM) in 21 streams spanning boreal to arctic Alaska, and assessed permafrost, topography, and attributes...
Categories: Publication;
Types: Citation;
Tags: 0414 Biogeochemical cycles,
0428 Carbon cycling,
0469 Nitrogen cycling,
0475 Permafrost,
0706 Active layer,
Conclusions:The occurence of bull trout in mid-boreal stream is negatively related to two metrics of industrial activity: percent forest harvesting and road density. Bull trout abundance was positively related to elevation, and negatively related to stream width, slope, and levels of forest harvesting.Thresholds/Learnings:Timber harvest on up to 35% or more of individual subbasins is projected to result in the extripation of bull trout from up to 43% of stream reaches, especially those that support high densities of bull trout.
Categories: Publication;
Types: Citation;
Tags: Land use configuration,
Landscape fragmentation,
Natural cover amount,
Western Alberta,
boreal forest,
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;...
Synopsis: This study monitored the response of a species of pine bark beetle, Trypodendron lineatum, to direct and indirect measures of habitat availability in a forest subjected to various levels of harvest intensities. Four stand types (conifer dominated, mixed, deciduous dominated, and deciduous dominated with conifer understory) were treated with four levels of harvest intensity (unharvested, 50%, 80%, and 90% harvested). Prior to harvest, the pine bark beetle was most abundant in stands with many host trees (conifer dominated stands). In the first and second summers after harvest, pine beetle abundance increased exponentially with percent spruce cover and the number of spruce stumps in the stand. Beetles were...
Categories: Publication;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Alberta,
Land use configuration,
Landscape fragmentation,
Natural cover amount,
Natural cover heterogeneity,
This dataset represents forest cover extent for the biome for year 2000. Forests were defined as areas with tree canopy cover greater than 25%. The Landsat-analyzed sample block classification results were used to calibrate biome-wide MODIS-derived forest extent. The relationship between Landsat-based forest cover area and mean VCF tree canopy density per sample block 18.5 km per side was used to derive forest extent for year 2000. A simple linear regression (no intercept) model was used with mean VCF tree canopy density per block as the independent variable. Data is displayed in grid format, with the value being percent forest cover per pixel.
Herbivores transform landscapes and affect succession via selective foraging that alters vegetation composition. In the boreal forest, mammalian herbivores, mainly moose, facilitate a shift toward the dominance of heavily defended species over time, such as white spruce. The effects of moose herbivory are intensified by the browsing of snowshoe hares. However, unlike moose, snowshoe hares also browse seedlings of white spruce. We quantified herbivory by snowshoe hares on white spruce along the Tanana River, interior Alaska, and assessed the effects on white spruce demography via two different herbivore exclosure experiments. We hypothesized that both experiments would show reduced plant density and height growth...
Categories: Data,
Publication;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Alaska,
Lepus americanus,
Picea glauca,
alternative successional trajectories,
boreal forest,
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;...
We used the Muskwa-Kechika Management Area in northeast British Columbia, Canada as a case study to determine potential conflicts between future resource development and high-value habitats of large mammals in an undeveloped boreal landscape. More than 50 % of high-value habitats for caribou, moose, elk, wolves and grizzly bears were located in Special Resource Management Zones, where natural resource developments could occur. We developed geographic information system (GIS) layers of potential forest resources, oil and gas, minerals, wind power, all resources combined, and roads; and quantified the proportions of high-value habitats overlapping these potentials. Greater proportions of high-value habitats across...
Categories: Data,
Publication;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Boreal forest,
British Columbia,
Habitat conservation,
Muskwa-Kechika Management Area,
Resource development,
The role of lynx dispersal in maintaining their populations at the landscape scale is unclear. A large proportion of local lynx populations are known to disperse following a snowshoe hare population crash, but whether these dispersal events contribute to the cyclic dynamics of neighboring populations is not well understood. If lynx dispersal does play an important role in lynx population dynamics then the conservation of dispersal corridors is critical to maintaining those dynamics. However, we currently have no information on the habitat requirements of dispersing lynx in relation to human land use, such as housing developments, road building, timber harvest, and mining, all of which could have a substantial impact...
Categories: Data,
Project;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: BIOSPHERE,
BIOSPHERE,
BOREAL FOREST/TIAGA,
EARTH SCIENCE,
EARTH SCIENCE,
This dataset represents 2000-2005 gross forest cover loss due to wildfires. A separate regression estimator (i.e. separate regression models and parameter estimates allowed for each stratum) and post-stratification were employed to estimate Landsat-calibrated forest cover loss area. For sample blocks with intensive change a simple linear regression model was applied using the proportion of area within the sample block classified as MODIS-derived forest loss as the auxiliary variable. For low-change blocks post-stratification based on VCF tree canopy cover and road density data was implemented to partition blocks into areas of nearly zero change and areas of some change. The forest cover loss area estimates were...
Conclusions: In response to logging, songbirds demonstrated “habitat compensation” by moving into different adjacent habitats across a fragmented landscape. Thresholds/Learnings: Synopsis: This study investigates the degree to which species respond differently to logging across different scales in Alberta’s boreal mixed-wood forests. Researchers tracked changes in the composition and abundance of songbirds at the patch-level and landscape level, finding significant variation between the two spatial scales. The results suggest that predictions of organism response based on the island biogeographic model are limited, and that—while responses varied across species—songbirds demonstrated “habitat compensation” by moving...
Categories: Publication;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Alberta,
Land use configuration,
Landscape fragmentation,
Natural cover amount,
birds,
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...
Categories: Publication;
Types: Journal Citation;
Tags: Alaska,
Boreal forest,
Chronosequence,
Machine learning,
Organic layer thickness,
Conclusions: Increasing seismic line density from 0 to 8 km/km2 resulted in a 38% decline and an 82% decline in bird abundance when individuals used lines as territory boundaries or avoided edges by 50 m, respectively. When tested with ovenbirds, male ovenbirds showed a distinct use of one side of the seismic line, suggesting lines acted as territory boundaries. Ovenbirds declined with seismic line density when a threshold seismic line density of 8.5 km/km2 was reached. Above the threshold, Ovenbirds declined 19% for each 1 km/km2 increase in seismic line density. Thresholds/Learnings: Synopsis: In the boreal plains of Alberta, Canada, energy sector exploration has resulted in extensive dissection of the landscape...
Categories: Publication;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Land use configuration,
Landscape fragmentation,
Northern Alberta,
bird abundance,
birds,
The study examined the effects of forest harvest practices that approximate natural disturbance processes to evaluate whether these practices help conserve biodiversity. Past research has shown that management practices that mimic natural disturbance events such as forest fires is a successful habitat conservation strategy, particularly for boreal forest bird communities. The study investigated how bird communities differed between postharvest and postfire stands in the mid-boreal region of Alberta. The research found that the most significant difference between postfire and postharvest landscapes is the amount and orientation of residual live and dead trees. Postfire stands consist largely of standing dead trees...
Categories: Publication;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Natural cover amount,
Northern Alberta,
birds,
boreal forest,
forest fire,
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