Skip to main content
Advanced Search

Filters: Tags: western North America (X)

17 results (66ms)   

Filters
Date Range
Extensions
Types
Contacts
Categories
Tag Types
Tag Schemes
View Results as: JSON ATOM CSV
Modern pollen assemblages from 18 small ponds and wetlands on the spatially isolated and forested Kaibab Plateau were studied to determine how the pollen assemblages recorded vegetation patterns. Vegetation of the Plateau consists of an inner core of subalpine Picea/Abies forests, surrounded by mixed Abies/Picea/Pseudotsuga/Pinus ponderosa forests, which are in turn surrounded by extensive Pinus ponderosa forests. The flanks of the Plateau are vegetated by Pinus edulis/Juniperus woodlands, with scattered Quercus populations. Arboreal pollen assemblages were dominated by Pinus (70-98%), which was most abundant in the P. ponderosa forests. Picea, Abies, Pseudotsuga and Populus pollen were abundant only at sites in...
thumbnail
Please contact fresc_outreach@usgs.gov if you have difficulty downloading the data files. We will explore alternative arrangements to deliver the data.
thumbnail
Genetic networks can characterize complex genetic relationships among groups of individuals, which can be used to rank nodes most important to the overall connectivity of the system. Ranking allows scarce resources to be guided towards nodes integral to connectivity. The greater sage-grouse (Centrocercus urophasianus) is a species of conservation concern that breeds on spatially discrete leks that must remain connected by genetic exchange for population persistence. We genotyped 5,950 individuals, from 1,200 greater sage-grouse leks distributed across the entire species’ geographic range.
Aim The influence of anthropogenic climate change on organisms is an area of great scientific concern. Increasingly there is recognition that abrupt climate transitions have occurred over the late Quaternary; studies of these shifts may yield insights into likely biotic responses to contemporary warming. Here, we review research undertaken over the past decade investigating the response of Neotoma (woodrats) body size and distribution to climate change over the late Quaternary (the last 40,000 years). By integrating information from woodrat palaeomiddens, historical museum specimens and field studies of modern populations, we identify potential evolutionary responses to climate change occurring over a variety of...
This map depicts the distribution of sagebrush and associated shrub-steppe habitat types using readily available data from a variety of source maps from WA, OR, CA, UT, NV, CO, WY, MT, ND, SD, AZ, NM, AB, and BC. Habitat was grouped from map sources that were classified with detailed information on specific sagebrush types, as well as coarse-scale maps that classified vegetation as only "shrub" in the case of ND and the Canadian provinces. This map is a 90-meter grid, but source material included 30 to 90-meter grids, and 1:24,000 and 1:100,000 polygon coverages.
Aim The influence of anthropogenic climate change on organisms is an area of great scientific concern. Increasingly there is recognition that abrupt climate transitions have occurred over the late Quaternary; studies of these shifts may yield insights into likely biotic responses to contemporary warming. Here, we review research undertaken over the past decade investigating the response of Neotoma (woodrats) body size and distribution to climate change over the late Quaternary (the last 40,000 years). By integrating information from woodrat palaeomiddens, historical museum specimens and field studies of modern populations, we identify potential evolutionary responses to climate change occurring over a variety of...
thumbnail
Heat load, a unitless value from 0 (low incident radiation) to around 1 (high incident radiation), is calculated using aspect, slope, and latitude (McCune and Dylan 2002). For the purposes of the exploration tool, the data are binned into 6 classes using Geometric Interval. Classes range from very low to very high and are designed to allow the classification of a polygon into its heat load types. McCune, B. and Keon, D., 2002, Equations for potential annual direct incident radiation and heat load: Journal of Vegetation Science, v. 13, no. 4, p. 603-606, https://doi.org/10.1111/j.1654-1103.2002.tb02087.x.
thumbnail
Functional connectivity, quantified using landscape genetics, can inform conservation through the identification of factors linking genetic structure to landscape mechanisms. We used breeding habitat metrics, landscape attributes and indices of grouse abundance, to compare fit between structural connectivity and genetic differentiation within five long-established Sage Grouse Management Zones (MZ) I-V using microsatellite genotypes from 6,844 Greater Sage-Grouse (Centrocercus urophasianus) collected across their 10.7 million-km2 range. We estimated structural connectivity using a circuit theory based approach where we built resistance surfaces using thresholds dividing the landscape into ‘habitat’ and ‘non-habitat’....
thumbnail
This dataset presents observations and measurements of riparian plant invasion, community composition, and environmental conditions at 238 bridge crossings in four western USA river basins: the Colorado Headwaters, upper/middle Rio Grande, upper Arkansas River, and South Platte River (281,946 square kilometers). The 238 sites are a stratified random sample of all bridge crossings in the river basins, with roughly equal numbers of sites in landscapes dominated by (1) urban and residential (developed) land-use, (2) agricultural (cultivated) land-use, and (3) undeveloped land cover. The dataset includes field observations of stem counts for three non-native riparian woody plant taxa (Tamarix ramosissima x T. chinensis...
Aim The geographical extent and climatic tolerances of one- and two-needled pinyon pines (Pinus subsect. Cembroides) are the focus of questions in taxonomy, palaeoclimatology and modelling of future distributions. The identification of these pines, traditionally classified by one- versus two-needled fascicles, is complicated by populations with both one- and two-needled fascicles on the same tree, and the description of two more recently described one-needled varieties: the fallax-type and californiarum-type. Because previous studies have suggested correlations between needle anatomy and climate, including anatomical plasticity reflecting annual precipitation, we approached this study at the level of the anatomy...
A new compilation of pollen and packrat midden data from western North America provides a refined reconstruction of the composition and distribution of biomes in western North America for today and for 6000 and 18,000 radiocarbon years before present (14C yr bp). Modern biomes in western North America are adequately portrayed by pollen assemblages from lakes and bogs. Forest biomes in western North America share many taxa in their pollen spectra and it can be difficult to discriminate among these biomes. Plant macrofossils from packrat middens provide reliable identification of modern biomes from arid and semiarid regions, and this may also be true in similar environments in other parts of the world. However, a...
thumbnail
"Vector Ruggedness Measure (VRM) measures terrain ruggedness as the variation in three-dimensional orientation of grid cells within a neighborhood. Vector analysis is used to calculate the dispersion of vectors normal (orthogonal) to grid cells within the specified neighborhood. This method effectively captures variability in slope and aspect into a single measure. Ruggedness values in the output raster can range from 0 (no terrain variation) to 1 (complete terrain variation). Typical values for natural terrains range between 0 and about 0.4. VRM was adapted from a method first proposed by Hobson (1972). VRM appears to decouple terrain ruggedness from slope better than current ruggedness indices, such as TRI or...
thumbnail
"Vector Ruggedness Measure (VRM) measures terrain ruggedness as the variation in three-dimensional orientation of grid cells within a neighborhood. Vector analysis is used to calculate the dispersion of vectors normal (orthogonal) to grid cells within the specified neighborhood. This method effectively captures variability in slope and aspect into a single measure. Ruggedness values in the output raster can range from 0 (no terrain variation) to 1 (complete terrain variation). Typical values for natural terrains range between 0 and about 0.4. VRM was adapted from a method first proposed by Hobson (1972). VRM appears to decouple terrain ruggedness from slope better than current ruggedness indices, such as TRI or...
thumbnail
Aim The recent concern that quaking aspen (Populus tremuloides Michx.) has been declining in parts of western North America due to fire suppression is largely based on trends during the latter part of the 20th century. The aim of the current study was to compare the extent of aspen in the modern landscape with its extent in the late 19th century prior to fire suppression, and to assess the effects of elevation, late-19th century fires, and pre-fire forest composition on the successional status of aspen. Location North-west Colorado, USA. Methods We used a georeferenced 1898 map and modern maps to examine trends in aspen dominance since the late 19th century in a 348,586 ha area of White River and Routt National...
Pacific trout Oncorhynchus spp. in western North America are strongly valued in ecological, socioeconomic, and cultural views, and have been the subject of substantial research and conservation efforts. Despite this, the understanding of their evolutionary histories, overall diversity, and challenges to their conservation is incomplete. We review the state of knowledge on these important issues, focusing on Pacific trout in the genus Oncorhynchus. Although most research on salmonid fishes emphasizes Pacific salmon, we focus on Pacific trout because they share a common evolutionary history, and many taxa in western North America have not been formally described, particularly in the southern extent of their ranges....
thumbnail
This data set depicts federal lands having restrictions on access or activities -- that is, lands mangaed by the National Park Service, Defense Department, or Energy Department -- in western North America. The data set was created by reformatting and merging state- and province-based ownership data layers originally acquired from diverse sources (including state GAP programs, USBLM state offices and other sources). For each original dataset 3 additional fields, "Pub_Pvt", "CA_OWN", and "SOURCE" were added and populated based on the specific ownership information contained in the source data. The original coverages were then merged based on the "CA_OWN" field. Finally, NPS, DOD, and DOE lands were selected out of...
thumbnail
Projected current and future distributions of Abies amabilis (Pacific silver fir), Abies grandis (Grand fir), Abies procera (Noble fir), Acer macophylla (Big leaf maple), Larix lyallii (Subalpine larch), Larix occidentalis (Western larch), Pinus albicaulis (Whitebark pine), Quercus garryana (Garry oak), Taxus brevifolia (Pacific yew), Thuja plicata (Western red cedar) based on empirical bioclimatic models. Tree distributions models were built using 42 climate and bioclimatic variables from Climate Western North America climate dataset (www.climatevulnerability.org). I used random forest to project USGS range maps (http://esp.cr.usgs.gov/data/little/) for historical (1961-1990) and five general circulation models...


    map background search result map search result map Influences of infrequent fire, elevation and pre-fire vegetation on the persistence of quaking aspen (Populus tremuloides Michx.) in the Flat Tops area, Colorado, USA Restricted Access Federal Lands in Western North America Distribution of Sagebrush and Associated Shrub-steppe Habitats in Western North America Projected baseline and future tree distributions in the Pacific Northwest for 10 species under five SRES A2 CMIP3 GCMs for 2070-2099 Western United States 30m Heatload Values Sample collection information and microsatellite data for greater sage-grouse across the species range generated 2013 - 2016 Western US Ruggedness Reclassified into 6 Classes Western United States 30m Raw Heatload Values Western United States Ruggedness Raw Values Woody riparian invasive plant presence, stem density, and rank dominance and environmental conditions in 2012 at 238 bridge crossings in the Colorado Headwaters, upper/middle Rio Grande, upper Arkansas, and South Platte River Basins, USA Sample collection information and microsatellite data used in a Network analysis of greater sage-grouse across the species range generated 2013 - 2016 Influences of infrequent fire, elevation and pre-fire vegetation on the persistence of quaking aspen (Populus tremuloides Michx.) in the Flat Tops area, Colorado, USA Woody riparian invasive plant presence, stem density, and rank dominance and environmental conditions in 2012 at 238 bridge crossings in the Colorado Headwaters, upper/middle Rio Grande, upper Arkansas, and South Platte River Basins, USA Sample collection information and microsatellite data for greater sage-grouse across the species range generated 2013 - 2016 Sample collection information and microsatellite data used in a Network analysis of greater sage-grouse across the species range generated 2013 - 2016 Restricted Access Federal Lands in Western North America Distribution of Sagebrush and Associated Shrub-steppe Habitats in Western North America Western United States 30m Raw Heatload Values Western United States 30m Heatload Values Western United States Ruggedness Raw Values Western US Ruggedness Reclassified into 6 Classes Projected baseline and future tree distributions in the Pacific Northwest for 10 species under five SRES A2 CMIP3 GCMs for 2070-2099