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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...
This dataset is the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3800 observations representing 27 temperature manipulation studies, spanning nine biomes and nearly two decades of warming experiments. Data for this study were obtained from a combination of unpublished data and published literature values. We find that although warming increases soil respiration rates, there is limited evidence for a shifting respiration response with experimental warming. We also note a universal decline in the temperature sensitivity of respiration at soil temperatures >25°C. This dataset includes 3817 observations, from control (n=1812), first (i.e., lowest or sole) level...
Conclusions:distance from edge and the habitat heterogeneity were the most important variables affecting bryophyte and lichen species richnessThresholds/Learnings:Temperature and light intensity decreased, and humidity increased up to 15m from the edge of fragments in the study.
We examined the effects of fire disturbance on permafrost degradation and thaw settlement across a series of wildfires (from ~1930 to 2010) in the forested areas of collapse-scar bog complexes in the Tanana Flats lowland of interior Alaska. Field measurements were combined with numerical modeling of soil thermal dynamics to assess the roles of fire severity and climate history in postfire permafrost dynamics. Field-based calculations of potential thaw settlement following the loss of remaining ice-rich permafrost averaged 0.6 m. This subsidence would cause the surface elevations of forests to drop on average 0.1 m below the surface water level of adjacent collapse-scar features. Up to 0.5 m of thaw settlement was...
Carbon release from thawing permafrost soils could significantly exacerbate global warming as the active-layer deepens, exposing more carbon to decay. Plant community and soil properties provide a major control on this by influencing the maximum depth of thaw each summer (active-layer thickness; ALT), but a quantitative understanding of the relative importance of plant and soil characteristics, and their interactions in determine ALTs, is currently lacking. To address this, we undertook an extensive survey of multiple vegetation and edaphic characteristics and ALTs across multiple plots in four field sites within boreal forest in the discontinuous permafrost zone (NWT, Canada). Our sites included mature black spruce,...
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...
Conclusions:Results indicated that system and species-specific considerations are important when assessing the potential outcome of habitat loss and fragmentation on regional biotaThresholds/Learnings:
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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...
We examined the effects of fire disturbance on permafrost degradation and thaw settlement across a series of wildfires (from ~1930 to 2010) in the forested areas of collapse-scar bog complexes in the Tanana Flats lowland of interior Alaska. Field measurements were combined with numerical modeling of soil thermal dynamics to assess the roles of fire severity and climate history in postfire permafrost dynamics. Field-based calculations of potential thaw settlement following the loss of remaining ice-rich permafrost averaged 0.6 m. This subsidence would cause the surface elevations of forests to drop on average 0.1 m below the surface water level of adjacent collapse-scar features. Up to 0.5 m of thaw settlement was...
Carbon release from thawing permafrost soils could significantly exacerbate global warming as the active-layer deepens, exposing more carbon to decay. Plant community and soil properties provide a major control on this by influencing the maximum depth of thaw each summer (active-layer thickness; ALT), but a quantitative understanding of the relative importance of plant and soil characteristics, and their interactions in determine ALTs, is currently lacking. To address this, we undertook an extensive survey of multiple vegetation and edaphic characteristics and ALTs across multiple plots in four field sites within boreal forest in the discontinuous permafrost zone (NWT, Canada). Our sites included mature black spruce,...
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Conclusions: Caribou mortalities attributed to wolf predation were generally closer to a corridor, indicating that linear corridors may enhance wolf predation efficiency. Therefore, caribou existing closer to linear corridors are at a higher risk of depredation than those farther from corridors. Thresholds/Learnings: Synopsis: This study tested the hypothesis that linear corridors affect caribou and wolf activities by examining the distribution of telemetry locations of caribou and wolves, as well as locations of caribou mortality and caribou predation by wolves relative to linear corridors caused by roads, seismic lines, power lines, and pipeline rights-of-way. Caribou mortalities attributed to wolf predation...
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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...
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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...
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...
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.
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;...
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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...
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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...
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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...
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;...
map background search result map search result map Chronic industrial noise affects pairing success and age structure of ovenbirds Seiurus aurocapilla. Distribution of caribou and wolves in relation to linear corridors Distribution of bark beetle, Trypodendron lineatum in a harvested landscape Potential conflict between future development of natural resources and high-value wildlife habitats in boreal landscapes Asynchronous recruitment dynamics of snowshoe hares and white spruce in a boreal forest Stage-dependent effects of browsing by snowshoe hares on successional dynamics in a boreal forest ecosystem Stage-dependent effects of browsing by snowshoe hares on successional dynamics in a boreal forest ecosystem Distribution of bark beetle, Trypodendron lineatum in a harvested landscape Distribution of caribou and wolves in relation to linear corridors Potential conflict between future development of natural resources and high-value wildlife habitats in boreal landscapes Asynchronous recruitment dynamics of snowshoe hares and white spruce in a boreal forest Chronic industrial noise affects pairing success and age structure of ovenbirds Seiurus aurocapilla.