Download or read book Relative Effects of Landscape and Local Habitat Characteristics on Grassland Songbird Abundance and Occurrence in Southwestern Manitoba written by Jessica Lockhart and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: I investigated the relative effects of grassland cover and fragmentation per se, and the relative influence of landscape and local habitat characteristics on grasslands songbirds in the moist mixed-grass prairies of Manitoba. In 2013, 361 avian point counts were conducted across 47, 2.4-km radii landscapes in the southwest part of the province. I used an information-theoretic approach to rank and select models describing effects of landscape and local-scale habitat variables on grassland songbird abundance and occurrence. Overall, my results indicate that grassland amount, fragmentation and quality, and matrix composition had relatively small and variable effects on grassland songbird abundance and occurrence, but that abundance of obligate species when pooled showed a strong negative response to grassland fragmentation. While fragmentation through edge effects may contribute to obligate species declines, my results suggest that these factors alone are unlikely to explain ongoing declines of grassland birds in southwestern Manitoba.

Download or read book Landscape effects on breeding songbird abundance in managed southern Appalachian forests written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many studies have demonstrated adverse effects of forest fragmentation on breeding forest songbirds in North America, and the viability of regional populations is thought to depend on large, unfragmented forests. However, we know relatively little about the landscape scale consequences of management in the forested landscapes that are presumed to be important to maintaining songbird metapopulations. The southern Appalachians, a mostly forested region, contains the largest network of public lands in the eastern U.S. Most of these public lands are managed by the U.S. Forest Service. To begin to understand the landscape scale effects of forest management in the southern Appalachians, I examined the relationship between the relative abundance of different species of breeding songbirds and local and landscape scale habitat variables in two predominately mid- to late-successional National Forests in the southern Appalachian Mountains, USA: the French Broad Ranger District of Pisgah National Forest (North Carolina) and the Nolichucky Ranger District of Cherokee National Forest (Tennessee). As part of the study, I explored two statistical problems frequently encountered in species-environment analysis: count data and spatial autocorrelation. Results from classical normal-errors regression models were similar to results from Poisson and negative binomial models that explicitly model counts. Normal-errors regression models were then modified to account for spatial autocorrelation using a conditional gaussian autoregressive model. Most species, especially Neotropical migrants, were significantly correlated with at least one landscape variable. These correlations included both landscape composition (i.e., the proportion of different landcover types) and landscape pattern (i.e., the spatial arrangement of landcover types) variables at 500 m to 2 km landscape scales. However, these landscape effects explained only a small fraction of the variation in bird relative abundance, and.

Download or read book Effects of Landscape Composition and Multi scale Habitat Characteristics on the Grassland Bird Community written by Timothy Dean McCoy and published by . This book was released on 2000 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measures of grassland bird demography on Conservation Reserve Program (CRP) fields were compared and modeled at several spatial scales to identify habitat factors associated with increased conservation value for grassland birds. Grassland bird populations and species richness were compared between fields located in landscapes with different amounts of CRP habitat and total grassland. Multi-scale habitat models were developed from and validated on two independent data sets to identify the primary habitat features that could predict the potential value of CRP and other idle grasslands for grassland bird conservation. The frequency of occurrence, abundance, and nest density of Henslow's sparrows (Ammodramus henslowii) and abundance of bobolinks (Dolichonyx oryzivorus) were higher in fields located in high grassland landscapes (55-75%) than low grassland landscapes (20-35%), whereas field sparrows (Spizella pusilla) were less likely to be present in high grassland landscapes. However, field sparrow reproductive performance was similar between high CRP, high grassland landscapes and the seemingly preferred low CRP, low grassland landscapes. Dickcissel (Spiza americana) and sedge wren (Cistothorus platensis) occurrence, song sparrow (Melospiza melodia) abundance, and red-winged blackbird (Agelaius phoeniceus) nesting success were higher in landscapes with high levels of CRP enrollment (20-35%) than those with low levels (5-12%). Multi-scale habitat models were useful for predicting occurrence and abundance of grassland birds, but not for predicting nesting success. The amount of woody edge around fields was negatively related to presence and abundance of several grasslandnesting species, whereas field sparrows (Spizella pussilla) were positively associated with the amount of woody edge around fields. Grasshopper sparrow (Ammodramus savannarum) and eastern meadowlark (Sturnella magna) occurrence and abundance increased with shorter, less dense vegetation, whereas common yellowthroat (Geothlypis trichas) presence and abundance and red-winged blackbird (Agelaius phoeniceus) abundance increased with taller, more dense vegetation. Grassland conservation and management efforts must recognize that habitat factors from several spatial scales may limit the conservation value of specific sites for grassland birds.

Download or read book The Influence of Patch Size Landscape Composition and Edge Proximity on Songbird Densities and Species Richness in the Northern Tall grass Prairie written by Laurel McDonald and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Area sensitivity of North American grassland birds is a significant conservation concern; yet, its causes are not known. I used point count data from 20 tall-grass prairie patches in Southern Manitoba to assess the relative importance of patch size, edge proximity, and landscape composition on the densities and species richness of grassland songbirds. The degree to which the landscape surrounding point count plots was open, as opposed to forested or urban, had a positive effect on species richness and the densities of most focal species, and was more important than patch size, edge proximity, or habitat amount. These results suggest that landscape openness, not patch size (with which it is usually correlated) drives area sensitivity. Small grassland patches embedded in open landscapes are less susceptible to area sensitivity and may be of high conservation value for grassland birds.

Download or read book Conspecific Attraction and Area Sensitivity of Grassland Songbirds in Northern Tall grass Prairie written by David Bruinsma and published by . This book was released on 2012 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many grassland songbird species exhibit sensitivity to patch size in North America's fragmented prairie ecosystems, but the mechanisms explaining this area sensitivity are not well understood. I tested the effects of patch size and artificial conspecific location cues (song playback and decoys) on grassland songbird abundance in 23 northern tall-grass prairies in Manitoba, Canada, in 2010 and 2011. Richness and relative abundances increased with patch area; this effect was not explained by differences in local habitat structure, patch configuration, and adjacent matrix. Artificial cues elicited putative territory prospecting in small, previously unoccupied treatment patches from two focal species, Savannah Sparrow (Passerculus sandwichensis; n=3 treatment sites) and Le Conte's Sparrow (Ammodramus leconteii; n=4 treatment sites), but not in control patches (n=3 for both focal species). Social information may influence the focal species' settlement decisions, but the lack of permanent settlement response suggests social cues are unable to reverse their area sensitivity.

Download or read book Developing Grassland Songbird Management Targets for Multi Species Conservation on Native Mixed Grass Prairie written by Phillip Kelsey Rose and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grassland birds are declining at steeper rates than birds from nearly every other habitat type, and the primary reasons for these declines are loss and degradation of native grasslands. Moisture, along with other environmental conditions such as soil type, topography, fire, and grazing, play important roles in determining the extent of habitat features important to grassland songbirds. I examined the associations between the abundance/occurrence of 14 grassland songbird species and vegetation characteristics along a moisture gradient in southwest Saskatchewan. Associations with at least one vegetation characteristic changed along the moisture gradient for 12 of the 14 species. Songbird abundance/occurrence was typically greater in areas with dense cover at drier sites along the moisture gradient when overall cover was sparse and greater in areas with sparser cover at wetter sites when overall cover was dense; however, absolute values for vegetation characteristics associated with peak abundance/occurrence often remained similar along the moisture gradient. The umbrella species concept is based on the premise that the conservation of a single species can also aid in conservation of a wide range of other co-occurring species with overlapping habitat requirements. I examined how the vegetation attributes of greater sage-grouse (Centrocercus urophasianus) critical habitat influenced grassland songbirds, and whether sage-grouse could potentially serve as an umbrella species for the grassland songbird community at the northern extent of the sage-grouse range. I found that abundance of Sprague's pipit (Anthus spragueii) and Baird's sparrow (Ammodramus bairdii) was lower and abundance of lark bunting (Calamospiza melanocorys) was higher within greater sage-grouse critical habitat in comparison to a 1.6 km buffer surrounding critical habitat. The abundance of all endemic grassland songbirds, except lark bunting, was negatively associated with vegetation attributes that characterized sage-grouse critical habitat (i.e., shrub and sagebrush cover). The vegetation characteristics associated with shrub-steppe songbirds and several grassland generalists overlapped with vegetation characteristics that defined greater sage-grouse critical habitat. Greater sage-grouse conservation is likely to have a positive influence on shrub-tolerant species, such as lark bunting, and a neutral or positive effect on generalist grassland species, but will provide few benefits to other grassland species at risk.

Download or read book The Influence of Habitat Features on Grassland Birds Nesting in the Prairie Pothole Region of North Dakota written by David Joseph Horn and published by . This book was released on 2000 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of habitat fragmentation studies on grassland and wetland birds are not consistent. Some studies have found positive relationships among abundance, nest success, field size, and distance to edges, whereas others have found no relationship. One reason for differing results may be the landscape composition in which the study took place. I examined how landscape composition influenced relations among: 1) occurrence and abundance of grassland songbirds and field size and 2) nest success of ducks, field size, and edges. I also investigated the effects of mowing on grassland songbirds, and how landscape features, such as amount of perennial grassland, and predator community composition influenced the nest success of ducks in fields. The study took place in the Prairie Pothole Region of central North Dakota during the 1996-1997 breeding seasons. Two types of 6.4 x 6.4 km study areas were selected based on the amount of perennial grassland they contained: 15-20% and 51-55%. The remaining portion of the study areas was primarily cropland and wetland.

Download or read book Demographic Responses of Grassland Songbirds to Rangeland Management in the Tallgrass Prairie written by Bram Hendrik Ferdinand Verheijen and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Grasslands are among the most rapidly declining ecosystems in the world. The Flint Hills ecoregion contains one of the largest remaining tracts of tallgrass prairie, but most of the area is managed with high densities of grazing animals and frequent prescribed burns, thereby reducing variation in vegetative structure. A homogeneous landscape leads to lower diversity and abundance of wildlife species, including grassland songbirds. Patch-burn grazing management has been proposed to more closely match the historical interaction between fire and selective grazing by native ungulates. Pastures managed with patch-burn grazing have a greater variety of vegetative structure and plant species composition, and as a result, higher species diversity, abundance, and reproductive success of grassland birds. However, past work has not considered potential effects of regional variation in predation risk and rates of brood parasitism by Brown-headed Cowbirds (Molothrus ater), or annual variation in climatic conditions on the effects of patch-burn grazing management on the reproductive success of grassland songbirds. Over a six year period and at two tallgrass prairie sites, I tested the effects of patch-burn grazing on the reproductive success of three native grassland songbird species, Dickcissels (Spiza americana), Eastern Meadowlarks (Sturnella magna), and Grasshopper Sparrows (Ammodramus savannarum), as well as subsequent effects on the space use, movements, and survival of fledgling Dickcissels. I found only minor effects of patch-burn grazing on the reproductive success of grassland songbirds, supporting previous studies that show that patch-burn grazing does not have negative effects on demographic rates of grassland songbirds. Management regime did not affect densities or territory size of male Dickcissels, but bird densities tended to be higher and territories tended to be smaller on patches within the patch-burn grazing treatment that were burned in the previous year. Thus, patch-burn grazing management might benefit Dickcissel populations by providing higher quality breeding habitat in unburned patches. Last, I found evidence for a potential tradeoff between habitat selection for nests vs. fledglings of Dickcissels in some rangeland management strategies. Parents that realized high reproductive success by nesting in pastures with lower cowbird densities, produced fledglings that faced high rates of depredation by snakes and showed greater movements away from those pastures. Survival rates and movements of Dickcissel fledglings were low, especially during the first week after leaving the nest, which stresses the importance of local habitat conditions. At a larger spatial scale, I tested whether regional differences in habitat structure could drive variation in apparent survival of grassland songbirds. I found that grassland- and shrubland-breeding species had higher estimates of apparent survival than forest-breeding species, contrary to the prevailing viewpoint that birds breeding in dynamic landscapes, such as frequently burned grasslands, should show lower apparent survival than species that breed in woody habitats. The results of my field study show that restoring the historical interaction between fire and grazing on the landscape via patch-burn grazing management could benefit grassland songbirds. Moreover, my dissertation is the first study that tests the effects of patch-burn grazing management on the survival and movements of fledgling Dickcissels, and shows that high cowbird densities can cause a tradeoff between different life-stages. Future conservation efforts should take into account regional variation in species abundance, predator community composition and abundance of Brown-headed Cowbirds when assessing the effects of rangeland management on the demography of grassland songbirds.

Download or read book Grassland Songbird Use of Waterfowl Nesting Cover in Southwestern Manitoba written by Kristina Menges Chouinard and published by . This book was released on 1999 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Oil Development on Grassland Songbirds and Their Avian Predators in Southeastern Saskatchewan written by Jason Howard Unruh and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The quantity and quality of Saskatchewan's remaining grassland may be threatened by energy development such as oil extraction. Grassland songbird populations are declining and increased oil development may be contributing to their declines through habitat loss and degradation. More quantitative research is needed to inform our understanding of how grassland songbirds are affected by oil development. I examined grassland songbird abundance, vegetation structure, habitat type (native and planted grasslands), and avian predator occurrence across a gradient of oil disturbance to determine the extent to which oil well proximity, density, and cumulative habitat disturbance influences the abundance of grassland songbirds and the occurrence of avian predators. I conducted 486 point counts in 243 sample sites (259 ha) at varying distances from oil wells, and in areas with varying well densities (0-48 wells/259 ha). The abundance of seven songbird species was reduced near oil wells or in areas with higher well densities, the abundance of two species was not influenced by oil wells, and the abundance of two species increased in the presence of oil wells or with greater well density. Three species also exhibited reduced abundance with greater cumulative disturbance, while two species exhibited reduced abundance when the area covered by well pads or oil access roads increased. I also found evidence that the abundance of four species was lowest in planted grassland compared to native grassland in the presence of oil development. My results indicate that oil development influenced vegetation structure, which likely influenced grassland songbird abundance to some degree. However, structural changes in vegetation did not account for all observed variation in songbird abundance. Finally, my results provide evidence that Northern Harrier occurrence is negatively influenced by oil development but that buteos and corvids are not affected. Northern Harrier occurrence is possibly influenced by habitat fragmentation caused by oil development since they are known to be area sensitive. As oil development increases in grassland habitat, its negative impacts on grassland songbirds will likely become more pronounced. Efforts should be made to limit well density and the cumulative area of disturbance on the landscape.

Download or read book Effects of Habitat Restoration on Breeding Grassland Songbird Habitat Use in Remnant Prairies of the Loess Hills Iowa written by Tracy A. Walker and published by . This book was released on 2005 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the central US, land use change has resulted in the loss and fragmentation of grassland habitats. We examined the influence of different restoration practices (burning and grazing, both separately and in combination) on native plants and grassland birds within the Loess Hills, Iowa at Broken Kettle Grasslands (BKG) Preserve in 2003-04. Vegetation characteristics varied significantly with treatment. Burned-only plots had more native plant species and a higher percentage of bare ground compared to other treatments, while grazed plots tended to have fewer shrubs, higher litter depth, and greater litter cover. Bird response to habitat restoration varied with treatment and species life history traits. Obligate grassland species, such as Grasshopper Sparrows (Ammodramus savannarum) and Western Meadowlarks (Sturnella neglecta), were consistently less abundant in burned-only treatments. In contrast, Dickcissels (Spiza americana), showed no difference among treatments, and woodland edge species, such as Lark Sparrows (Chondestes grammacus), were more abundant in these areas. Grasshopper Sparrows selected nest sites with short vegetation and a shallow litter layer, whereas Dickcissels selected nesting habitat closer to and with a higher percentage of tall shrubs. Patterns in nest success and seasonal productivity were opposite those shown in relative abundance. Grasshopper Sparrows preferred to nest in habitat that had been grazed, yet nest success and seasonal productivity were highest in burned-only treatments. These results suggest that grazing may have a negative effect on grassland bird populations at BKG. Consequently, we recommend a restoration approach that includes both burning and grazing, considering timing and distribution of grazing regimes, for sustaining populations of threatened grassland bird species with varying habitat preferences.

Download or read book Grassland Songbird Community Relationships Mediated by Cattle Stocking Rates and Plant Community Composition in Two Habitats in a Northern Mixed Grass Prairie written by Kelsey Molloy and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grassland birds are experiencing the most significant declines of any avian guild in North America. Grazing is an important tool to manage habitats for these species, as they respond to structural changes in vegetation, and grazing affects vegetation structure. I studied the impact of cattle stocking rates grassland songbird abundances, with upland and lowland habitats in Grasslands National Park, Saskatchewan, Canada, 2006 to 2012. I also examined relationships between songbird abundance and plant community composition. Generalized linear mixed models were used for analyses. Species differed in responses to increased grazing (0 to 0.85 AUM/ha); Sprague's pipit responded negatively, whereas chestnut-collared longspur responded positively. Above average precipitation during the study likely reduced the grazing effects. Overall, a range of cattle stocking rates makes habitat available for a complete songbird community. Efforts focused on prairie conservation should manage grazing at stocking rates that produce habitats that are under-represented relative to surrounding grasslands.

Download or read book Songbird Habitat Models on the Landscape scale in Southeast Ohio s Public Forestland written by Kaley Jean Donovan and published by . This book was released on 2016 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the Appalachian Foothills Region of Ohio, active timber management provides an opportunity for sustainable management of forest resources and conservation for the long term viability of songbirds. This region also contains the highest biodiversity of birds within the state. With continued declines in bird populations and increased conservation attention placed on songbirds, it is important to capture how forest management and wildlife responses are linked. Birds have been the focus of critical research that provides essential information of how fine scale patterns such as vegetation structure influence population processes. However, if and how these patterns transfer to the broader landscape where forest management decisions are made remains unclear. The aim of this research was to add to current knowledge of habitat relationships of songbirds by sampling across a broad extent to identify the relative influence of landscape and local features on bird species occurrence. In addition, by considering unique disturbance histories implemented at the state forest scale, I quantified how these activities influence occupancy of focal species. Birds were surveyed at 280 point count locations in 2015 and 2016 in Southeast Ohio across Tar Hollow and Zaleski State Forests, and Vinton Furnace State Experimental Forest. Comprehensive habitat models were developed for five focal species of conservation concern representative of varying forest successional stages using occurrence data, detailed vegetation data, and remotely sensed data for land cover composition and landform variables. I found the majority of focal species were affected by management and structural variables, but relationships varied in direction and magnitude. Early-successional habitat, classified as even-aged timber harvests ten years old or younger, strongly positively affected Prairie Warblers (Setophaga discolor), weakly positively affected Eastern Towhees (Pipilo erythrophthalmus), strongly negatively affected Cerulean Warblers (Setophaga cerulean), and weakly negatively affected Wood Thrushes (Hylocichla mustelina). For example, with an increase from 20% to 100% early-successional habitat within 75-m of a point count, an increase from 37% to 99% probability of occurrence was predicted for Prairie Warblers. Kentucky Warblers (Geothlypis formosa) did not show associations with any variables. I also found that occupancy of Cerulean Warblers was greater while Prairie Warbler and Eastern Towhee occupancy was less in Zaleski State forest compared to Vinton Furnace State Experimental Forest, which can be attributed to the greater amount of early-successional habitat within the landscape at Vinton (~21% compared to ~6%). To bring these two analyses together, I projected habitat suitability across the forests to illustrate how these focal species’ associations with land cover overlap in space. These results provide an informative component towards planning for conservation at the landscape level within state forestland in Southeast Ohio, and lend support to providing a mosaic of conditions to optimize habitat for a variety of forest songbirds.

Download or read book Landscape Characteristics Affecting Grassland Birds on Fields Enrolled in the Conservation Reserve Program written by Mary Ann Cunningham and published by . This book was released on 2001 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Natural Gas Development and Grassland Songbird Abundance in Southwestern Saskatchewan written by Holly Jayne Kalyn Bogard and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Marcellus Shale Development on Songbird Abundance and Habitat Use in Northcentral Pennsylvania Forests written by Ethan Barton and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to recent instability in the international petroleum products market, American industries are seeking to develop domestic sources of energy, and foremost among these domestic sources is natural gas. The Marcellus Shale formation in the northeastern portion of the United States contains a vast portion of the natural gas reserve of North America; the northeastern US also contains many large core forest reserves important for breeding songbirds. Within the last decade, development of wells within the Marcellus has rapidly expanded, and the number of wells permitted for drilling has increased steadily. In forested areas, Marcellus development creates large disturbances and causes substantial fragmentation, but the landscape matrix remains dominated by stands of mature forest. I examined the effects of Marcellus Shale gas development on songbird abundance and habitat use surrounding 30 well pads, mean size 2 hectares, placed within an extensive forest landscape in northcentral Pennsylvania. I used fixed-radius point counts to assess songbird abundance relative to well pads at four distances from the pad edge: two points in new edge habitat (0m and 50m) created by pad development and two points in remnant post-development interior habitat (150m and 250m), which served as a reference. I conducted bird and vegetation surveys in both northern hardwood and mixed oak habitat. To determine whether bird abundance and species composition differed between edge and reference points, I analyzed the aggregate avian community at edge and interior points and also built linear mixed models for three guilds of species based upon habitat preference: forest interior, early-successional, and synanthropic species. I also constructed linear mixed models for individual bird species within the guilds observed at >=50% of field sites. Avian communities differed between forest interior and pad edge, and they also differed by forest habitat type (northern hardwood or oak) overall and at interior reference points. However, communities did not differ by forest habitat type at edge points, indicating biotic homogenization may be occurring near well pads. Forest interior species were significantly less abundant near the pad edge relative to interior reference points. Interior habitat associates such as black-throated green warblers (Setophaga virens), black-throated blue warblers (Setophaga caerulescens), ovenbirds (Seiurus aurocapilla), red-eyed vireos (Vireo olivaceus), hermit thrushes (Catharus guttatus), and scarlet tanagers (Piranga olivacea) were less abundant at edge points than within the forest interior. In contrast, synanthropic species were more abundant near pad edges than at interior points. American robins (Turdus migratorius) were more abundant within 100m of well pad edges than at reference points within the forest interior surrounding well pads. Distance from edge was not a significant predictor of abundance for the early successional species guild or individual species associated with the guild. Common yellowthroats (Geothlypus trichas) and eastern towhees (Pipilo erythrophthalmus), two species associated with early successional habitat, did not exhibit a detectable response to development. I took nested-plot vegetation samples at points surrounding well sites to assess vegetative changes near well pads as a possible explanation for bird distribution. Average canopy cover, mean litter depth, the number of tree stems >8cm diameter at breast height, and the number of small sapling stems

Download or read book Effects of Shallow Gas Development on Relative Abundances of Grassland Songbirds in a Mixed grass Prairie written by Jennifer Anne Rodgers and published by . This book was released on 2013 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mixed-grass prairie -- grassland songbirds.