Skip to main content
Advanced Search

Filters: Tags: Land use configuration (X)

114 results (11ms)   

Filters
Date Range
Extensions
Types
Contacts
Categories
Tag Types
Tag Schemes
View Results as: JSON ATOM CSV
Conclusions: Report outlines habitat-based biodiversity standards specific to the prairie ecozone. It is intended to contribute to the delivery of habitat-based biodiversity standards in the prairie region via landscape-level indicators and targets Thresholds/Learnings: Synopsis: This report synthesizes the work completed to date on habitat-based biodiversity standards specific to the prairie ecozone. The intent of this report is to contribute to the delivery of habitat-based biodiversity standards in the Prairie region via landscape-level indicators and targets. Examples of key landscape targets for prairie landscapes that were identified included: * A minimum of 3 to 7% (<10%) of each major watershed should be...
thumbnail
Synopsis: This study attempts to build a forest fragmentation database for the conterminous United States by utilizing high-resolution NLCD data, roads, and a series of fragmentation indices that quantify forest landscape patterns. The paper outlines a methodology for assessing forest fragmentation and provides a comprehensive data set to be used as a base for further investigation at smaller scales. Conclusions: A forest fragmentation database for the conterminous United States was built to quantify forest landscape patterns nationwide. The paper outlines a methodology for assessing forest fragmentation and provides a comprehensive data set to be used as a base for further investigation at smaller scales. Thresholds/Learnings:...
Conclusions:Influx of woody vegetation associated with fragmentation correlates with decline in grassland bird speciesThresholds/Learnings:When native grassland cover dropped below 60% at one site, and 30-40% at another site, the arrangement or habitat patches became more important to the survival of populations than habitat amount alone
Conclusions:Document serves as a guide to consistent reporting for Alberta’s State of the Watershed Reports. It outlines a framework for reporting watershed conditions by providing specific criteria and direction to guide consistency in reporting. Framework includes major indicators of watershed health, including section on land cover and pattern indicators which provide critical thresholds for road density impacts to wildlifeThresholds/Learnings:Road density thresholds: grizzly bears- 0.4 km/km2; elk- 0.62 km/km2; black bears- 1.25 km/km2. Road densities for bull trout: 0.0-0.1 km/km2 = low risk; 0.1-0.2 km/km2 = moderate risk; 0.2-0.6 km/km2 = high risk; 0.6-1.0 km/km2 = very high risk; >1.0 km/km2 = extripation....
thumbnail
Synopsis: The effects of the 17,400 ha Cerro Grande fire patch in New Mexico on erosion and sedimentation processes were analyzed by this study, located in the Jemez Mountains upstream of the Los Alamos Reservoir, New Mexico. This study provides a unique data set demonstrating post-fire erosion rates relative to pre-fire conditions. The fire affected a large fraction of the watershed, with 32% of the basin experiencing a moderate to high severity burn, including some of the steepest mountainous portions of the basin. Average sediment deposition was 150 m3/year prior to the fire, equivalent to an average basin-wide denudation rate of 0.009 mm/year. The year after the fire, over 21,800 m3 of sediment accumulated in...
thumbnail
Conclusions: Marten capture rates were negatively correlated with increasing proximity of open areas and increasing extent of high-contrast edges. Forested landscapes were unsuitable for martens when the average nearest-neighbor distance between open, non-forested patches was <100m. Thresholds/Learnings: Synopsis: This study aimed to determine whether American marten abundance changed with incremental increases in habitat fragmentation caused by the combined effects of natural openings and timber clearcuts. Researchers evaluated differences in marten capture rates in 18 study sites with different levels of fragmentation. Martens appeared to respond negatively to low levels of habitat fragmentation, even with remaining...
thumbnail
Conclusions: Elk habitat selection ratios varied in response to road pattern. Regularly spaced roads negatively influenced habitat selection, whereas a clumped pattern supported larger blocks of road-free habitat. Road density threshold at which elk could still occur in high numbers: 1.5 km/km⊃2; Thresholds/Learnings: Road density threshold at which elk could still occur in high numbers: 1.5 km/km⊃2; Synopsis: This study tested 3 aspects of an elk road density model to determine patterns of elk behavior relative to road density and configuration. The study compared model predictions with observed values of elk habitat selection at varying levels of road density. It also compared the effect of different spatial...
thumbnail
Synopsis: Agronomic intensification has transformed many agricultural landscapes into expansive monocultures with little natural habitat. A pervasive concern is that such landscape simplification results in an increase in insect pest pressure, and thus an increased need for insecticides. We tested this hypothesis across a range of cropping systems in the Midwestern United States, using remotely sensed land cover data, data from a national census of farm management practices, and data from a regional crop pest monitoring network. We found that, independent of several other factors, the proportion of harvested cropland treated with insecticides increased with the proportion and patch size of cropland and decreased...
thumbnail
Synopsis: Because recent bark beetle population eruptions have exceeded the frequencies, impacts, and ranges documented during the previous 125 years, researchers have been prompted to determine what factors trigger broad scale outbreaks, and how do these factors interact? How do human activities, such as forest management, alter these interactions, and thus the frequency, extent, severity, and synchrony of outbreaks? Extensive host tree abundance and susceptibility, concentrated beetle density, favorable weather, optimal symbiotic associations, and escape from natural enemies must occur jointly for beetles to surpass a series of thresholds and exert widespread disturbance. Eruptions occur when key thresholds are...
thumbnail
Synopsis: Large scale natural disturbances from wildfire and severe insect infestations can significantly impact water quality downstream of forested headwaters. Forest fires impact water quality due to sediment input of the ash and soot and by chemical changes to surface and groundwater. This has recently been extensively studied in southwestern Alberta, after the “Lost Creek” wildfire of 2003. Four years of comprehensive hydrology and water quality data from seven watersheds were evaluated and synthesized to assess the implications of wildfire and post-fire intervention (salvage logging) on downstream drinking water treatment. Burned and unburned reference watersheds were examined by the authors. Far more contaminants...
Conclusions:Bird and medium sized mammal population densities were affected by the arrangement and density of exurban housing developments, with both species groups avoiding developments up to 180 away. The composition of native wildlife is altered in the vicinity of exurban housing developments.Thresholds/Learnings:Avian densities were altered up to 180m away from homes on the perimeter of ex-urban developments.
Conclusions: Book provides a comprehensive introduction to the principles and theories in landscape ecology. Early chapters introduce basic concepts and terminology that build a foundation for understanding more complex issues such as landscape disturbance dynamics, formulas and metrics for quantifying landscape patterns, and predictive models of landscape change. Thresholds/Learnings:
Conclusions:The effects of adjacent land-use on wetland sediment and water quality can extend over comparatively large distances. As such, sustaining high wetland water quality will not be achieved merely through the creation of narrow buffer zones between wetlands and more intensive land-uses, but rather by maintaining a heterogeneous regional landscape containing relatively large areas of natural forest and wetlands.Thresholds/Learnings:Water nitrogen and phosphorous levels were negatively correlated with forest cover at 2250m from the wetland edge. Sediment phosphorous levels were negatively correlated with wetland size and forest cover at 4000m from the wetland edge, and positively correlated with the proportion...
thumbnail
Conclusions: In response to logging, songbirds demonstrated “habitat compensation” by moving into different adjacent habitats across a fragmented landscape. Thresholds/Learnings: Synopsis: This study investigates the degree to which species respond differently to logging across different scales in Alberta’s boreal mixed-wood forests. Researchers tracked changes in the composition and abundance of songbirds at the patch-level and landscape level, finding significant variation between the two spatial scales. The results suggest that predictions of organism response based on the island biogeographic model are limited, and that—while responses varied across species—songbirds demonstrated “habitat compensation” by moving...
thumbnail
Synopsis: This study investigated the magnitude of change in landscape structure resulting from road and logging since the onset of timber harvesting in 1950. Overall, roads were found to have had a greater impact on landscape structure than logging. A three-fold increase in road density between 1950 and 1993 accounted for most of the changes in landscape configuration including mean patch size, edge density, and core area. Change in landscape structure varied as a function of landscape extent. At a large scale of 228,000 ha, change in landscape change over time was trivial, suggesting that the landscape is capable of incorporating disturbances with minimal impact. At intermediate scales of 1000-10,000 ha, change...
Conclusions: Imperviousness can be used as a general indicator of potential development impacts on water resources when making land use decisions. Thresholds/Learnings: Threshold values of imperviousness on overall stream health are generalized from literature review: protected (less than 10%), impacted (10% - 30%), and degraded (more than 30%). However, as indicated in other studies, these thresholds are of questionable value.
Conclusions:Presents condition and pressure indicators for land, water quantity, water quality, and aquatic and riparian systems, as a series of categorized indicators of environmental quality. These broadly include: land quality condition indicators, land use pressure indicators, water quantity pressure indicators, water quality pressure indicators, and indicators of aquatic and riparian ecosystem health.Thresholds/Learnings:
Conclusions:Higher percentages of forest cover within the watershed and within a 30m buffer were related to healthy fish communities and water quality, while near stream grasslands and urban land cover in the watershed contributed negatively to the health of fish communities and water quality.Thresholds/Learnings:High percentages of forest cover within a 30m riparian buffer were related to healthy fish communities and water quality. Fish density increased with increase in the average length of riparian vegetation without gaps (>30m).
Conclusions:Unsuitable habitat surrounding a patch of suitable habitat creates islands of high species density from which successful dispersion becomes difficult. Therefore, habitat surrounding a patch, rather than the quality of the patch itself, may be a more important determining factor of species abundance.Thresholds/Learnings:
Conclusions:Patch area was shown to be an important determinant of species richness irrespective of habitat heterogeneity. Isolation in space was also a significant factors in determining the degree of species richness in a grassland landscape.Thresholds/Learnings:
map background search result map search result map The influence of forest fragmentation and landscape pattern on American martens. Fragments are not islands: patch vs landscape perspectives on songbird presence and abundance in a harvested boreal forest. Elk distribution and modeling in relation to roads A Five Year Record of Sedimentation in the Los Alamos Reservoir, New Mexico, Following the Cerro Grande Fire Implications of land disturbance on drinking water treatability in a changing climate: Demonstrating the need for source water supply and protection strategies. Forest fragmentation of the coterminous United States: assessing forest intactness through road density and spatial characteristics. Cross-scale drivers of natural disturbances prone to anthropogenic amplification: the dynamics of bark beetle eruptions Comparative evaluation of experimental approaches to the study of habitat fragmentation effects Agricultural landscape simplification and insecticide use in the Midwestern United States. A Five Year Record of Sedimentation in the Los Alamos Reservoir, New Mexico, Following the Cerro Grande Fire Elk distribution and modeling in relation to roads Implications of land disturbance on drinking water treatability in a changing climate: Demonstrating the need for source water supply and protection strategies. Fragments are not islands: patch vs landscape perspectives on songbird presence and abundance in a harvested boreal forest. The influence of forest fragmentation and landscape pattern on American martens. Comparative evaluation of experimental approaches to the study of habitat fragmentation effects Agricultural landscape simplification and insecticide use in the Midwestern United States. Forest fragmentation of the coterminous United States: assessing forest intactness through road density and spatial characteristics. Cross-scale drivers of natural disturbances prone to anthropogenic amplification: the dynamics of bark beetle eruptions