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Road features were identified using TIGER line data and those features mapped as freeways, secondary roads and local roads were selected. A moving window analysis was applied, which used a window area of 640 acres to determine the miles of road per 640 acres. Output from the analysis was scored where road density values less than 3 miles/640acres were scored as a 3 (“preferred”) and road density values greater than 3 miles/640acres received a score of 1 (“lower quality”).
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Conclusions: Caribou subpopulation persistence and landscape occupancy depends highly on the degree of forest cover, cover type, and distance from human presence. Thresholds/Learnings: Synopsis: This study evaluates factors influencing the persistence and landscape occupancy of caribou subpopulations in southern British Columbia. Data from 235 radio-collared caribou across 13 subpopulations were used to derive a landscape occupancy index. The index was analyzed against 33 landscape variables including, land cover, terrain, climate, and human influence. At the metapopulation level, the persistence of subpopulations correlated with the extent of wet climate conditions and the distribution of old forests and alpine...
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Image of lenth of roads per 1 km-square pixel, derived from streets and roads layers of Census Bureau TIGER 98 files. Pixel values are sum lengths of streets and major roads (including interstate highways) in units of meters. For more information about the TIGER files see the following url: http://www.census.gov/geo/www/tiger/
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This dataset depicts indices of forest fragmentation within the U.S. Northeast region. This dataset can help inform prioritization of landscapes for conservation through identification of more intact forested areas. Forest fragmentation was assessed using information derived from the National Land Cover Dataset (NLCD) and USGS 1:100,000 scale roads. Within each forested ecoregion in the World Wildlife Fund ecoregions dataset, landscape units (land units) were defined using U.S. Census Bureau TIGER highway networks. Land units were blocks of forested land bounded by highways and were required to be at least 2,000 hectares in size. Land units smaller than 2,000 hectares or areas within urban areas were excluded from...
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Road densities derived from the TIGER data were analyzed to determine the relationship between road density and Bald eagle potential suitable habitat. The quality of a HUC in relation to road density was defined as good (3), fair (2), or poor (1). The score indicates the threat level for each attribute. A low score indicates a low threat, a medium score indicates a medium threat, and a high score indicates a high threat to the species. The values for each score were characterized in relation to road density by >10 km/km2 = good, 5-10 km/km2 = fair, and 2 = poor.
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This tabular data set represents select basin characteristics compiled for two spatial components of the NHDPlus version 2 data suite (NHDPlusv2) for the conterminous United States; 1) individual reach catchments and 2) reach catchments accumulated upstream through the river network. The select variables in this data set are parsed out into six different file themes as follows: BASIN_CHAR_XXX_CONUS.txt (where XXX is CAT flowline catchment value, ACC is divergence routed accumulated value, and TOT is total upstream routed accumulated value) contains information on stream slope (percent rise, also referred to as the percent slope), basin slope (percent rise, also referred to as the percent slope), basin area, minimum...
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The 2000 Rogue River aquatic integrity analysis used road density, road-stream intersections, forest change and fish barriers as surrogate indicators of watershed integrity. High road density contributes to increased levels of erosion and sedimentation and consequent alterations to hydrological patterns and degradation of water quality (OCSRI 1997). In addition, watersheds with higher road densities provide easier human access and are correlated with higher levels of disturbances from human activities that degrade water quality and aquatic habitat integrity (Frissell et al. 1996, Roth et al. 1996).
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This road density dataset can inform the Clearwater Basin Collaborative about where to establish "working areas" of more active timber management across the Basin.
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Road features were identified using TIGER line data and those features mapped as freeways, secondary roads and local roads were selected. A moving window analysis was applied, which used a window area of a square kilometer to determine kilometers of road per square kilometer. Output from the analysis was scored based on the following criteria where road density values less than 0.18km/km2 were scored as a 3 (“preferred”), densities between .18 and 1.0518 km/km2 scored as a 2, and road density values greater than 1.0518km/km2 received a score of 1 (“lower quality”)
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Road density can inform "working areas" of more intensive harvest activities within the Clearwater Basin Collaborative
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Simple road density calculated as miles of road per square mile. Thus, a 1 square mile circular window was used to sum the length of road for each 30 meter cell. I relied only on Clearwater and Nez Perce National Forest roads datasets.
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Conclusions: Report describes the development of a multi-metric, fish-based Index of Biological Integrity (IBI) to assess the health of aquatic ecosystems on the Battle River, Alberta. The IBI was highly sensitive to cumulative anthropogenic disturbance. Impaired integrity of fish assemblages was detectable at road densities as low as 0.7km/km2 Thresholds/Learnings: Impaired integrity of fish assemblages was detectable at road densities as low as 0.7km/km2. Synopsis: Report describes the development of a multi-metric, fish-based Index of Biological Integrity (IBI) to assess the health of aquatic ecosystems on the Battle River, Alberta. The IBI was highly sensitive to cumulative anthropogenic disturbance. Impaired...
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Conclusions: Reduction in landscape carrying capacity for wolf population distribution and viability depends largely on the degree of road density, public land ownership, amount of forest cover and high elk densities (another indicator of suitable habitat). Synopsis: This study employed two types of spatial models to evaluate the potential of wolf reintroduction in the southern Rocky Mountain region. A multiple logistic regression was used to develop a resource-selection function relating wolf distribution in the Greater Yellowstone region with regional-scale habitat variables. Researchers also used a spatially explicit population model to predict wolf distribution and viability at several potential reintroduction...
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This road density dataset can inform "working areas" that are appropriate for more active timber harvest according to the Clearwater Basin Collaborative
We attempted a complete review of the empirical literature on effects of roads and traffic on animal abundance and distribution. We found 79 studies, with results for 131 species and 30 species groups. Overall, the number of documented negative effects of roads on animal abundance outnumbered the number of positive effects by a factor of 5; 114 responses were negative, 22 were positive, and 56 showed no effect. Amphibians and reptiles tended to show negative effects. Birds showed mainly negative or no effects, with a few positive effects for some small birds and for vultures. Small mammals generally showed either positive effects or no effect, mid-sized mammals showed either negative effects or no effect, and large...
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Low Road Density This layer is one of the South Atlantic LCC indicators in the landscapes “habitat aggregate”, which is intended to capture connections across all terrestrial ecosystems. It is an index of areas with few roads. Reason for Selection Large areas with few roads are favorable for conservation of numerous species, including reptiles and amphibians, birds, and large mammals. Roads can cause negative impacts by promoting dispersal of invasive species and inhibiting water flow. Road density, as well as urban expansion in areas of low road density, are straightforward to measure and monitor. Road density has been used in other broad-scale conservation planning efforts and is widely used and understood by...
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.
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Conclusions: Habitat associations of prairie rattlesnakes appear to differ depending on whether snakes are hibernating, foraging, or reproducing. Most rattlesnake hibernacula occur within 4 km of a major river, drainage, or coulee, on relatively gentle slopes, but they migrate as far as 25 km away from dens in summer. High road densities present unfavorable habitat conditions for snakes because they are a significant cause of mortality. *Note that this study generated landscape level models with coarse variables, and the thresholds and values used may not be directly applicable to other areas or for site-specific analysis. Thresholds: Most rattlesnake hibernacula occur within 4 km of a major river, drainage, or...
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Conclusions: Results offer support for the use of land cover as an indicator of biotic integrity estimated by both vegetation and bird communities. Strong, significant predictions of IBI scores in plant and bird communities were achieved using land cover data from every spatial extent. Plant-based IBI scores were best predicted using data from 100 m buffers and bird-based IBI scores were best predicted using data extracted from 500 m buffers. Road density and measures of the proportion of disturbed land were consistent predictors of IBI score, suggesting their universal importance to plant and bird communities. Thresholds/Learnings: Road effects on bird communities were most pronounced at the 500m spatial extent....
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Road densities derived from the TIGER data were analyzed to determine the relationship between road density and Bald eagle potential suitable habitat. The quality of a HUC in relation to road density was defined as good (3), fair (2), or poor (1). The score indicates the threat level for each attribute. A low score indicates a low threat, a medium score indicates a medium threat, and a high score indicates a high threat to the species. The values for each score were characterized in relation to road density by >10 km/km2 = good, 5-10 km/km2 = fair, and 2 = poor.


map background search result map search result map Factors influencing the dispersion and fragmentation of endangered mountain caribou populations Impacts of landscape change on wolf restoration success: planning a reintroduction program based on static and dynamic spatial models. A fish-based index of biological integrity for assessing river condition in Central Alberta The accuracy of land cover-based wetland assessments is influenced by landscape extent. Prairie Rattlesnake. Road density (length in meters/sq. kilometer) for the contiguous U.S. Greater than 7 Miles of Road per Square Mile within the Clearwater Basin Road Density Greater Than 3 Miles of Road per Square Mile in the Clearwater Basin Road Density Greater Than 2 miles of Road per Square Mile within the Clearwater Basin Road Density Across the Clearwater Basin National Forests Aquatic integrity scores based on road density for watersheds of the Lower/Middle Klamath and Sacramento Rivers U.S. Forest Fragmentation - Northeast Indicator V 2.1: Landscapes - Low Road Density Attributes for NHDPlus Version 2.1 Catchments and Modified Routing of Upstream Watersheds for the Conterminous United States: Select Basin Characteristics BLM REA NGB 2011 Road Density near Bald Eagle suitable habitat (GAP) (Winter) BLM REA NGB 2011 Road Density Score for Modeled Pronghorn Habitat BLM REA NGB 2011 Road Density near Bald Eagle suitable habitat (GAP) (Summer) BLM REA NGB 2011 Road Density for Modeled Mule Deer Summer and Year long Habitat Prairie Rattlesnake. The accuracy of land cover-based wetland assessments is influenced by landscape extent. Aquatic integrity scores based on road density for watersheds of the Lower/Middle Klamath and Sacramento Rivers Road Density Across the Clearwater Basin National Forests A fish-based index of biological integrity for assessing river condition in Central Alberta Greater than 7 Miles of Road per Square Mile within the Clearwater Basin Road Density Greater Than 3 Miles of Road per Square Mile in the Clearwater Basin Road Density Greater Than 2 miles of Road per Square Mile within the Clearwater Basin Factors influencing the dispersion and fragmentation of endangered mountain caribou populations BLM REA NGB 2011 Road Density Score for Modeled Pronghorn Habitat BLM REA NGB 2011 Road Density for Modeled Mule Deer Summer and Year long Habitat BLM REA NGB 2011 Road Density near Bald Eagle suitable habitat (GAP) (Winter) BLM REA NGB 2011 Road Density near Bald Eagle suitable habitat (GAP) (Summer) Impacts of landscape change on wolf restoration success: planning a reintroduction program based on static and dynamic spatial models. U.S. Forest Fragmentation - Northeast Indicator V 2.1: Landscapes - Low Road Density Attributes for NHDPlus Version 2.1 Catchments and Modified Routing of Upstream Watersheds for the Conterminous United States: Select Basin Characteristics Road density (length in meters/sq. kilometer) for the contiguous U.S.