Filters: Tags: M1-Ecosystems (X)
817 results (12ms)|
Filters
Date Range
Extensions Types
Contacts Categories |
Categories: Publication;
Types: Citation;
Tags: M1-Ecosystems,
R1-Vulnerability Forest Species and Communities to Climate Change
Categories: Publication;
Types: Citation;
Tags: M1-Ecosystems,
P2-Changes in Plant and Animal Species Due to Climate Change
Categories: Publication;
Types: Citation;
Tags: M1-Changes in Plant and Animal Distributon,
M1-Ecosystems
Categories: Publication;
Types: Citation;
Tags: M1-Changes in Plant and Animal Distributon,
M1-Ecosystems
Abstract. We compared the species composition and species density of vascular plants in the understorey vegetation of boreal forest between Picea mariana (Black spruce) and Populus tremuloides (Trembling aspen) stands in British Columbia, Canada, and related differences in species composition and species density between the two forest types to dominant canopy tree species as well as a wide variety of environmental factors. We analysed 231 stands, distributed in three different climatic regions representing drier, wetter, and milder variations of montane boreal climate. Of these stands 118 were dominated by P. mariana and 113 by P. tremuloides. P. tremuloides stands had higher species density than P. mariana stands...
Categories: Publication;
Types: Citation;
Tags: B4-Ecological Land Classification Scheme,
M1-Ecosystems,
M1-Flora
The importance of large woody debris (LWD) in forested stream ecosystems is well documented. However, little is known about LWD in northern boreal forest streams. We investigated the abundance, characteristics, and function of LWD in 13 small tributary streams of the upper Yukon River basin, Yukon Territory, Canada. LWD abundance was similar to values reported from temperate regions, whereas LWD size and total volume were well below values for the Pacific Northwest. LWD formed 28% of the pools, which provide important habitat for juvenile chinook salmon (Oncorhynchus tshawytscha Walbaum). The median diameter of pool-forming pieces was 17 cm, and ring counts on fallen riparian trees indicated that pool-forming pieces...
Assists professionals in applying the hydrogeomorphic approach in functional assessment modelling of precipitation/shallow ground water driven slope/flat complexes in the Cook Inlet basin ecoregion. Intended to be used with the National action plan to develop the hydrogeomorphic approach for assessing wetland functions (Federal register, v. 61, no. 160). ill. (some col.), col. maps ; 28 cm.; Note(s): Additional authors on t.p.: Jim Powell, Stan Carrick, Ted Rockwell, Garry Hollands, Todd Walter, Joe White./ "Developed for: State of Alaska, Department of Environmental Conservation"--Cover./ "June 2003."/ Includes bibliographical references (p. 103-104).; Other Titles: Wetland assessment guidebook for slope/flat wetland...
Categories: Publication;
Types: Citation;
Tags: B1-High Resolution Land Cover Imaging,
M1-Ecosystems
The North America boreal forest extends across more than 10° of latitude from central Labrador to interior Alaska. Periods of major climate fluctuations, including glacial and interglacial cycles, drove major migrations in the Quaternary history of the boreal forest. Beringia, the unglaciated region between the Lena and Mackenzie rivers, is recognized as an important refugium for arctic plants during the last ice age, but its role for boreal trees remains controversial. The paleobotanical record indicates Populus balsamifera (balsam poplar) survived within Beringia during the last glacial. My research employed an interdisciplinary approach, combining techniques in the fields of ecology, evolution and population...
1.?Ecosystem properties may be determined by the number of different species or groups of species in a community, the identity of those groups, and their relative abundance. The mass ratio theory predicts that the effect of species or groups of species on ecosystem properties will be dependent on their proportional abundance in a community. 2.?Single plant functional groups (graminoids, legumes, non-leguminous forbs) were removed from a natural grassland in northern Canada to examine the role of group identity in determining both ecosystem properties and biomass compensation by remaining species. Removals were conducted across two different environmental treatments (fertilization and fungicide) to examine the context...
Categories: Publication;
Types: Citation;
Tags: B4-Ecological Land Classification Scheme,
M1-Ecosystems,
M1-Flora
Our objective was to determine how Picea glauca (Moench) Voss trees on the Yukon plateau developed over time through the analysis of tree trunks. Our general null hypothesis was: if year-to-year climatic variation is the primary factor determining the magnitude of yearly radial growth, then within-tree and between-tree dendrochronological comparisons of annual ring width should generate Pearson product-moment correlation coefficients (PMCCs) near 1 for similar timberline position and, plausibly, lower PMCCs when comparing trees at different positions. Ring widths of nine trees were sequentially measured across the four cardinal direction radii of disks taken from 1 m trunk intervals. PMCCs of those radial series...
The objective of this study was to examine the impact of summer throughfall on the growth of trees, at upland and floodplain locations, in the vicinity of Fairbanks, Alaska. Corrugated clear plastic covers were installed under the canopy of floodplain balsam poplar/white spruce stands and upland hardwood/white spruce stands to control soil moisture recharge as a result of summer precipitation. The covers were installed in 1989 and tree growth measurements were conducted through 2005. Soil moisture dynamics were measured using TDR techniques. Tree basal area growth at dbh in the control plots was approximately twice as high on the floodplain compared to the upland. Summer throughfall exclusion significantly decreased...
At northern high latitudes, biosphere responses to and interactions with climate warming are expected to be significant during the 21st century. Most predictions of climate?biosphere interactions rely on experiments and observations in contemporary landscapes, e.g., modern distributions of vegetation types and their structural features are used to delimit potential biosphere?atmosphere feedbacks. Paleorecords look beyond the present to examine vegetation configurations under climatic regimes that approximate future scenarios. To enhance the knowledge of arctic and subarctic ecosystems under varying climatic conditions, we analyzed pollen and macrofossil data from Beringia (northeast Siberia, Alaska, and northwest...
|
