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Conclusions:The Sprague's pipit tends to occupy native grassland habitats containing very little or no woody vegetation, with non-native areas populated to a significantly lower extentThresholds/Learnings:
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Synopsis: The purpose of this model is to indicate potential habitat for olive-backed pocket mice (Perohnathus fasciatus) within the Milk River Basin. As this is a landscape level model with course variaqbles, it may not be directly applicable to other areas for site-specific analysis. Conclusions: Olive-backed pocket mice require high proportions of grassland habitat and low proportions of shrub cover. Sites with low densities of shrubs are preferred because they provide cover from large and aerial predators, such as owls. A threshold of below 40% shrub coverage represents ideal shrub cover proportions.
Conclusions:Landscapes dominated by woody vegetation had significantly more patches, smaller patches and patch core areas, more total edge, and higher patch diversity than landscapes dominated by anthropogenic cover types. Results indicate that expanding juniper is exacerbating the fragmentation process initiated by previous human activityThresholds/Learnings:
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Synopsis: Using multi-scale seasonal models, this study explored how broad scale landscape context and local resource heterogeneity influenced local resource selection among threatened forest-dwelling woodland caribou in southern Quebec. Caribou consistently avoided roads, however researchers identified thresholds in road proximity effects. The threshold distance at which caribou avoid roads is 1.25 km for active roads and 0.75 km from derelict roads. Open lichen woodlands were an important cover type for caribou during winter and spring, whereas deciduous forests, wetlands, and even young disturbed stands became important during calving and summer. Landscape cover type and amount explained more variation in habitat...
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Synopsis: In an attempt to better characterize the influence of human settlement patterns on wolf distribution, this paper examined how radio-collared gray wolves responded to different road types and human presence at the boundaries of Kenai National Wildlife Refuge in south-central Alaska. Wolves tended to avoid oilfield access roads that were open to the public, but were attracted to gated pipeline access roads and secondary gravel roads with limited human use. The low use access and secondary roads likely provided an easy travel corridor for wolves. Prior to intensive trapping and hunting from 1978-1979, wolves demonstrated little territorial adjustment in response to a heavily used highway. However, only after...
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Synopsis: This study evaluates whether previous observations of a higher percentage of parasitism and parasitoid diversity in a complex agricultural landscape, relative to a simple landscape, represent a general phenomenon. Rates of parasitism and parasitoid diversity of the armyworm (Pseudaletia unipuncta) were assessed in three replicate (Onondaga, Ingham, and Benton) regions in southern Michigan. Within each region, a simple landscape (primarily cropland) and a complex landscape (cropland intermixed with mid and late successional noncrop habitats) were identified through analysis of aerial photographs. In each landscape, three maize fields were selected, and second to fourth instar P. unipuncta were released...
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Conclusions: Grizzly bears can use roaded habitats, but spatial avoidance will increase and survival will decrease as traffic levels, road densities and human settlement increases. Road density standards and road closure programmes should be developed and that these programmes incorporate seasonal habitat requirements of grizzly bears. Thresholds/Learnings: More than 80% of bear sitings occurred in blocks of undisturbed habitat >900 ha Synopsis: The study examined the relationships between grizzly bears, habitat and roads in the Swan Mountains, Montana. The study showed complex spatial and temporal relationships between grizzly bears and habitat resources. Resource selection was expressed relative to strength...
Conclusions:Report presents draft outcomes, indicators, and targets for the Red Deer River Basin in three topic areas: wetlands, riparian areas, and land use. Targets established were based on a detailed literature review, combined with Geographic Information Systems (GIS) queries of existing conditions.Thresholds/Learnings:Specific thresholds for the region include: wetland cover should comprise >7.5% of the watershed; peatland cover should comprise > 6.0% in the upper headwaters; 82% of all riparian areas (variable width) in the watershed should have perennial vegetation cover; 97% of all riparian areas (variable width) in the Upper Headwaters should have perennial vegetation cover
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Synopsis: Remotely sensed data and GIS were used to compare the effects of clear-cutting and road-building on the landscape pattern of the Bighorn National Forest, Wyoming. Landscape patterns were quantified for each of 12 watersheds on a series of four maps that differed only in the degree of clear-cutting and road density. Researchers analyzed several landscape pattern metrics for the landscape as a whole and for the lodgepole pine and spruce/fir cover classes across the four maps to determine the relative effects of clear-cutting and road building on the pattern of each watershed. At both the landscape and cover class scales, clear-cutting and road building resulted in increased fragmentation as represented...
Conclusions:Landscape features affect rates of brood parasitism. Rates of parasitism correlate with proximity to woody vegetation along patch edges. Influx of woody vegetation is associated with roadsides and grazing.Thresholds/Learnings:
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Synopsis: This study investigates the relationships of landscape disturbance, altered prey resources, and rattlesnake populations in the Upper Snake River Plain of southeastern. Researchers used radio telemetry to track rattlesnakes while concurrently conducting habitat sampling and small mammal trapping in areas used by snakes and in random locations. Disturbed areas (by grazing and/or burning) were characterized by lower biological crust cover, shrub cover, shrub height, and shrub dispersion, as well as higher grass and bare soil cover. Disturbed areas were also characterized by lower proportions of small animal biomass, abundance, and large prey species (such as chipmunks), while the proportions Conclusions:...
Synopsis: One recent study examining Eurasian watermilfoil (Myriophyllum spicatum L., hereafter milfoil) invasions using landscape-level variables found that the amount of forest land cover in the catchment is consistently negatively related to milfoil presence (Buchan and Padilla, 2000). These results suggest that further research is needed to examine the relationships between natural and anthropogenic landscape features and macrophyte cover. The ability of lake and landscape features to predict a variety of macrophyte cover metrics using 54 north temperate lakes were examined. Univariate regression analyses demonstrated that these macrophyte cover metrics are predicted by a wide range of predictor variables, most...
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Synopsis: This report evaluates habitat requirements of the American badger according to parameters of soil texture, graminoid cover, slope, and proximity to roads. Badgers tend to prefer sandy loam and silty loam, medium and moderately coarse textured soils. In terms of graminoid coverage, badgers generally prefer open grassland habitat, but can also be found in agriculturally dominated landscapes containing isolated pockets of Richardson 's ground squirrel colonies. Graminoid coverage of 23% was chosen as the minimum requirement for suitable badger habitat. As slope increases, habitat suitability decreases to a point at which the likelihood of badgers existing there (i.e. cliffs and badlands) is extremely low...
Conclusions:High proportions of native grass and low proportions of shrub cover are critical habitat components for maintaining viable sharp tailed grouse populations. *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/Learnings:Ideal shrub cover ranges from 5% to 15% and the ideal proportion of native grassland cover is >75% for sharp-tailed grouse*.
Conclusions:Forest clearcutting differentialy affects birds of different ages. There is a threshold distance between reserves below which birds do not mind crossing clear cuts, making corridors more important as clearcut area and distance between forest reserves expandsThresholds/Learnings:
Conclusions:Report summarizes studies on the impacts of agricultural land use on water quality within Alberta. The impacts of agricultural activities on water quality depend strongly on the amount and distribution of land under cultivation, as well as other measures of agricultural intensity such as fertilizer expenses, chemical expenses and animal unit densities. Generally, streams draining watersheds with more agriculture had higher concentrations of nutrients, bacteria, and pesticides.Thresholds/Learnings:
Conclusions:The effects of landscape fragmentation depend on habitat structure, landscape context, the predator community, and the impact of parasitism. Because these factors differ substantially in western ecosystem compared to eastern forest ecosystems, it is difficult to make universal generalizations about the effects of landscape fragmentation on ecosystem processes and wildlife dynamicsThresholds/Learnings:
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Conclusions: The study recorded flushing responses (whether or not an animal fled in response to disturbance) and flush distances of 6 species of diurnal raptors exposed to walking and vehicle disturbances in order to calculate minimum distances for species-specific buffer zones. In general, walking disturbances resulted in more flushing than vehicle disturbances for all species except the prairie falcon. For walking disturbances, a linear relationship existed between flight distance and body mass, with lighter species flushing at shorter distances; however, this trend did not hold for vehicle disturbance. Birds flushed at much shorter distances in response to approaching vehicles. Thresholds/Learnings: Buffer...
Conclusions:Report reviews how forests and their management affect the quality and quantity of downstream municipal water supplies in the state of OregonThresholds/Learnings:When >25% of the watershed's forest cover is clearcut in a short period of only a few months, there is a measurable increase in annual streamflows from the watershed.
Conclusions:Within a watershed, about 10% of development is not subject to drainage regulations resulting in cumulative effects from urbanization that significantly degrade watersheds. Instead of regulatory thresholds (e.g. 10% EIA), process controls are required to mitigate the impacts of urbanization on aquatic systems. Without these controls, strict development limits are the only way to limit watershed degradation.Thresholds/Learnings:The study cautions against the use of discrete “thresholds” to predict specific physical and biological effects, but does suggest that thresholds are appropriate indicators for when the perception and tolerance of watershed impacts triggers a regulatory response.
map background search result map search result map Assessing the influence of resource co-variates at multiple spatial scales: an application to forest-dwelling caribou faced with intensive human activity. Gray wolf response to refuge boundaries and roads in Alaska. Linking landscape disturbance to the population ecology of Great Basin rattlesnakes (Crotalus oreganus lutosus) in the Upper Snake River Plain Relationships among grizzly bears, roads, and habitat in the Swan Mountains, Montana. Watershed analysis of forest fragmentation by clearcuts and roads in a Wyoming forest Does agricultural landscape structure affect parasistism and parasitoid diversity? Olive-backed Pocket Mouse. Response of wintering grassland raptors to human disturbance. American Badger. American Badger. Assessing the influence of resource co-variates at multiple spatial scales: an application to forest-dwelling caribou faced with intensive human activity. Relationships among grizzly bears, roads, and habitat in the Swan Mountains, Montana. Response of wintering grassland raptors to human disturbance. Olive-backed Pocket Mouse. Does agricultural landscape structure affect parasistism and parasitoid diversity? Gray wolf response to refuge boundaries and roads in Alaska. Watershed analysis of forest fragmentation by clearcuts and roads in a Wyoming forest Linking landscape disturbance to the population ecology of Great Basin rattlesnakes (Crotalus oreganus lutosus) in the Upper Snake River Plain