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Conclusions: Valleys are the only areas capable of sustaining sufficient habitat for the butterfly species, Weidemeyer's Admiral. Consequently, all other areas (i.e. plains, uplands, benches, escarpments, plateaus) were deemed unsuitable. Additionally, areas devoid of shrub cover did not meet the habitat requirements of this specialized species. Thresholds/Learnings: Synopsis: Two variables were selected to model potential habitat for the butterfly species, Weidemeyer's Admiral. Topographical features derived from the Agricultural Region of Alberta Soils Inventory Database (AGRASID) and percent shrub cover derived from the Native Prairie Vegetation Baseline Inventory developed by Alberta Environment were used to...
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Synopsis: This study examines the influence of landscape fragmentation on trophic cascades in southern California. Results indicate that, as habitat fragmentation negatively affects the persistence of coyote populations, the abundance of smaller meso-predators increase, resulting in higher mortality rates in scrub-breeding birds. Fragment size was a strong indicator of coyote abundance, and coyote abundance was a strong indicator of bird diversity, as coyotes kept down the number of meso-predators that prey on birds. The positive effect of fragment area and the negative effect of fragment age were the strongest determinants of bird diversity in this system. Conclusions: Fragment size correlates with coyote abundance,...
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Conclusions: Summarizes findings from a review of literature intended to identify critical thresholds for conservation based in empirical studies of landscape fragmentation. Presents a conceptual overview of landscape fragmentation and habitat loss, as well as guidelines and thresholds relating to landscape indicators such as patch size, habitat amount, edge effects, riparian buffers, and habitat connectivity. Thresholds/Learnings: Many. See Kennedy et al. 2003. Synopsis: This report summarizes findings from a review of literature intended to identify critical thresholds for conservation based in empirical studies of landscape fragmentation. In presenting a conceptual overview of landscape fragmentation and habitat...
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Conclusions: Richardson's ground squirrels prefer short grass native prairie / pasture but can also occupy small isolated islands within cropland. These squirrels prefer open prairies and tend to select against heavily forested areas. *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: A threshold amount of 20% graminoid coverage is the minimum suitable proportion for habitat suitability for Richarson's ground squirrel. Areas with less than 20% forest/shrub cover were considered sutiable habitat, while those greater than 40% were considered unsuitable*. ...
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Synopsis: The short-horned lizard is Alberta's only lizard. It is indigenous to semi-arid, short grass portions of the northern Great Plains and usually found in rather rough terrain. This report evaluated habitat suitability requirements for the short-horned lizard according to the following parameters: Topographical Features: Most of the daily movement patterns during the summer rarely exceeded 30m, and generally occurred along the slopes of the valleys or valley bottoms. Consequently, all valleys and all prairie habitat within 100m of valleys are considered the best potential habitat. Native Prairie Class: Native Prairie Class (NPC) is derived from the Native Prairie Vegetation Baseline Inventory developed...
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Synopsis: The objective of this study was to examine initial effects of the 2003 Lost Creek wildfire (southwestern Rocky Mountains of Alberta) on concentrations and production (yield and total export) of several nitrogen (N) forms, and to explore initial recovery of these effects within the first 3 years after the fire. During the first postfire year, nitrate (NO3–), dissolved organic nitrogen (DON), and total nitrogen (TN) concentrations in severely burned watershed streams were 6.5, 4.1, and 5.3 times greater, respectively, than those in reference streams. Weaker effects were evident for concentrations of ammonium (NH4+; 1.5 times) and total particulate nitrogen (TPN; 3.0 times). A rapid decline in mean watershed...
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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: Elk consistently selected for big basin sagebrush, greasewood, and tree cover; and consistently selected against Wyoming sagebrush, mixed shrub, and bare ground/sand. Selection patterns were similar during the winter, except big basin sagebrush and mixed shrubs were selected in proportion to their availability. Elk tend to prefer areas characterized by edge habitat where quality forage and cover habitats are in close proximity to one another. Thresholds/Learnings: Elk use was highest in summer in areas characterized by diverse habitats and >2800m away from major roads. High use areas during winter were similar, although elk tended to use areas slightly closer to roads (>2100m away), which is largely...
Conclusions: Assessments of metapopulation structure must consider landscape pattern, but also the non-linear responses of organisms to such patterns Thresholds/Learnings: Synopsis: This study used beetles to empirically test the reliability of neutral percolation models to predict critical thresholds of landscape connectivity. Beetle movements declined sharply when grass cover dropped below 20% of the experimental plot. The findings of this study differed from what was predicted by the model, indicating that landscape connectivity is not dependent on spatial pattern alone, but is also highly dependent how individual organisms move within and among patches depending on the amount of cover. The results suggest that...
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Conclusions: At small spatial scales, where extirpation risks are high, landscape fragmentation will likely have long-term negative consequences on the genetic variation of individual assemblages of coastal cutthroat trout. Thresholds/Learnings: Synopsis: This study aimed to determine if coastal cutthroat trout were genetically structured within streams and to assess the effects of habitat fragmentation on coastal cutthroat trout genetic variation. Habitat fragmented by roads and other human disturbances acted as dispersal barriers, which strongly influenced coastal cutthroat trout genetic structure, diversity, and differentiation. At range-wide spatial scales, fragmentation potentially contributes to coastal cutthroat...
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Conclusions: There was a significant reduction in ovenbird pairing success at compressor sites (77%) compared with noiseless wellpads (92%). These differences were apparent regardless of territory quality or individual male quality. Noise interferes with a male's song, such that females may not hear the male's song at greater distances and/or females may perceive males to be of lower quality because of distortion of song characteristics Thresholds/Learnings: Synopsis: Anthropogenic noise is rapidly increasing in wilderness areas as a result of industrial expansion. This study assessed pairing success and age distribution of male ovenbirds, Seiurus aurocapilla, in the boreal forest of Alberta, Canada, in areas around...
Synopsis: This book provides important foundational concepts in landscape ecology, with a particular focus on the effects of land use and landscape fragmentation. Building on Forman’s patterns of landscape change, the book cites the McIntyre and Hobbs model of landscape change, which suggests that landscape modification often increases through time. Four broad classes of landscape condition can therefore be identified along a continuum of increasing human landscape modification: intact, variegated, fragmented, and relictual (figure 3). Similarly to Forman’s model, these classes represented correspond to different spatial patterns in the landscape. Therefore, as the extent of human land use increases, the amount...
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Conclusions: Prescribed burns did not supply the stream ecosystem with potentially important nutrient pulses that are often observed after wildfires. Prescribing higher severity burns to more closely mimic wildfires would enhance N cycling in productivity in N-limited headwater watersheds. Thresholds/Learnings: Synopsis: This study aimed to compare the short-term effects of spring prescribed burns and wildfires on Nitrogen cycling dynamics in headwater watersheds of central Idaho. Fire affected N dynamics in both terrestrial and aquatic components of the watershed ecosystem after wildfires but were limited to the terrestrial ecosystem after prescribed burns. Streamwater NO3 concentrations were affected significantly...
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Synopsis: Natural habitats are considered inherently indispensable to the global economy by conservationists, but few natural ecosystems afford direct and quantifiable economic benefits. Quantification of natural land value can provide compelling evidence favoring preservation over development. Wild bees are important pollinators of many crop plants, and natural patches in agroecosystems enhance pollinator services and crop yield. Bee abundance was greatest in canola fields that had more uncultivated land within 750 m of field edges and seed set was greater in fields with higher bee abundance. A cost–benefit model that estimates profit in canola agroecosystems with different proportions of uncultivated land is presented....
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Conclusions: The nature of the surrounding matrix contributes significantly to the degree of patch isolation; matrix modification may improve habitat connectivity and genetic distribution in fragmented landscapes. Thresholds/Learnings: Synopsis: This study challenges traditional assumptions about the uniform nature of the matrix, and the reliance on distance alone as an indicator of patch isolation, by testing whether the type of inter-patch matrix contributes significantly to patch isolation in butterfly populations. The author tracked the movement of six butterfly species between patches of meadow habitat through two natural matrix types (conifer forest and willow thicket). All taxa of butterflies studied responded...
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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...
Conclusions:When riparian vegetation is maintained in areas of intensive agriculture, suspended solids levels are generally lower due to reduced in-stream organic production. Sediment deposition in near stream areas and stream bank scour are also reduced when riparian vegetation is present.Thresholds/Learnings:
Conclusions:Over time, native species richness increased slightly, but dropped dramatically after several years of burning. Year-to-year change in community composition was found to be affected by time since fire and fluctuations in growing season temperature and rainfall. Examining successional trajectory showed that the restoration has been most successful at reducing exotic species and increasing species heterogeneity, but has largely failed to increase native species richness at the level of remnant prairies, largely due to interspecies resource competition.Thresholds/Learnings:
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: Although there was not a detectable decrease in bird communitiy species richness resulting from experimental forest fragmentation, community structure was altered, and maintaining connections between fragments significantly mitigated these effects. Thresholds/Learnings: Synopsis: This study examined the effects of forest fragmentation on the richness, diversity, turnover, and abundance of breeding bird communities in old boreal mixed-wood forest by creating experimental forest fragments of 1, 10, 40, and 100 ha. Connected fragments were linked by 100 m wide buffer strips. The study detected no significant change in species richness as a result of forest harvesting, except in the 1 ha connected fragments...
map background search result map search result map Are boreal birds resilient to forest fragmentation? An experimental study of short-term community responses. Chronic industrial noise affects pairing success and age structure of ovenbirds Seiurus aurocapilla. The matrix matters: effective isolation in fragmented landscapes. Weidemeyer's Admiral Conservation Thresholds for Land Use Planners Influences of barriers to movement on within-watershed genetic variation of coastal cutthroat trout Effects of spring prescribed burning and wildfires on watershed nitrogen dynamics of central Idaho headwater areas Seasonal distribution and habitat use patterns of elk in the Jack Morrow Hills Planning Area Richardson's Ground Squirrel. A fish-based index of biological integrity for assessing river condition in Central Alberta Short-horned Lizard Pollinators provide economic incentive to preserve natural land in agroecosystems Wildfire Impacts on nitrogen concentration and production from headwater streams in southern Alberta's Rocky Mountains. Prairie Rattlesnake. Mesopredator release and avifaunal extinctions in a fragmented system. Influences of barriers to movement on within-watershed genetic variation of coastal cutthroat trout The matrix matters: effective isolation in fragmented landscapes. Wildfire Impacts on nitrogen concentration and production from headwater streams in southern Alberta's Rocky Mountains. Are boreal birds resilient to forest fragmentation? An experimental study of short-term community responses. Seasonal distribution and habitat use patterns of elk in the Jack Morrow Hills Planning Area Effects of spring prescribed burning and wildfires on watershed nitrogen dynamics of central Idaho headwater areas A fish-based index of biological integrity for assessing river condition in Central Alberta Mesopredator release and avifaunal extinctions in a fragmented system. Chronic industrial noise affects pairing success and age structure of ovenbirds Seiurus aurocapilla. Pollinators provide economic incentive to preserve natural land in agroecosystems Richardson's Ground Squirrel. Conservation Thresholds for Land Use Planners