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 Spatial and Temporal Scales of Distribution and Demography in Breeding Songbirds written by Robert J. Fletcher and published by . This book was released on 2003 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tallgrass prairie has declined throughout the midwestern United States during the past two centuries, and migratory birds breeding in these habitats have also experienced precipitous population declines. One conservation strategy used to mitigate the effects of habitat loss and fragmentation is habitat restoration. I studied how both habitat fragmentation and restoration affect songbird populations breeding in grassland and wetland habitats in northern Iowa, 1999-2002. Most grassland birds tended to be less abundant near edges, yet birds avoided woodland edges more so than other types of edges. Edge avoidance could not be explained by changes in habitat structure. For Bobolinks (Dolichonyx oryzivorus), edge avoidance also increased near corners of sites, where multiple edges converged. These local patterns of edge avoidance were consistent with observed patterns of area sensitivity when scaling patterns up to fragmented landscapes using simulation modeling in neutral (randomized) landscapes. Moreover, regression modeling at landscape scales suggested that edge density metrics were better than landscape compositional metrics at explaining bird density within patches. Habitat restoration provided breeding habitat for many bird species, in which birds tended to occur at high densities in restored patches relative to other land cover types in the landscape. However, demographic data revealed a more complex pattern. In restored wetlands, reproduction was tied closely to interannual climate variation. In particular, nest predation was negatively correlated with water depth in wetlands. In restored grasslands, nest success tended to be relatively low for most species. Population projection models suggested that for Dickcissels (Spiza americana) and, to a lesser extent, Bobolinks, population growth rates were not high enough to be sustainable without immigration into the area ([mu]

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 Avian Nest Survival and Snake Abundance in Restored and Remnant Grasslands in Northwestern Iowa written by L. Embere Hall and published by . This book was released on 2005 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intensive agriculture in the Midwest has drastically reduced the amount of grassland on the landscape. Today less than 0.1% of the pre-settlement prairie remains. Consequently, native wildlife populations have declined. In recent years federal initiatives such as the Conservation Reserve Program and the North American Waterfowl Management Plan (now part of the North American Bird Conservation Initiative) have responded to these declines by providing incentives for large scale restoration of perennial grassland. Little is known, however, about how restored habitats function compared to remnant grasslands. I studied the impacts of restoration on grassland birds and snakes in northwestern Iowa though two distinct, though interconnected questions. First, I compared avian nest success on restored and remnant grasslands. During the 2003 and 2004 breeding seasons, I located nests in 10 restored and 6 remnant grasslands. Survival estimates were compared to examine the impact of current restoration efforts on local bird productivity. Dickcissels (Spiza americana), Bobolinks (Dolichonyx oryzivorus), Red-winged Blackbirds (Agelaius phoeniceus) and Clay-colored Sparrows (Spizella pallida) nested in both habitat types. We used logistic-exposure models and AIC model selection to examine variation in daily survival rates. The effect of habitat type was relatively weak, indicating restored grasslands in highly fragmented agricultural landscapes can provide comparable habitat for grassland-breeding birds, even if the restoration efforts do not mirror native habitat conditions. Second, I compared snake abundance within 100m of a gravel road to abundance in the interior of restored grasslands. Through the use of artificial shelters, we captured 694 individuals of four species during 16 survey weeks. Sixty-six percent of the captures were plains garter snakes (Thamnophis radix). We found no significant difference between interior and edge snake abundance, indicating that grassland snake abundance is not influenced by road edges at the scale we measured. Results from this study will help guide future efforts to develop high-quality habitat for grassland birds and snakes in agricultural landscapes.

Download or read book Grassland Butterfly Responses to Prairie Restoration written by Jennifer Amy Vogel and published by . This book was released on 2006 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fire and grazing are common methods used for prairie restoration and conservation. However, effects of restoration on grassland invertebrates have been evaluated with mixed results. We examined the effects of prairie restoration through fire and grazing and the relative contributions of the direct and indirect effects of time since fire on the grassland butterfly community of the Loess Hills of Iowa, USA. Both total and habitat-specialist (prairie-dependent) butterfly abundance were highest on prairies that were managed with grazing and burning, and lowest on those that were only burned. Butterfly species richness did not differ among any of the management types. Responses of individual butterfly species to management practices were variable. In the best predictive models, both habitat-specialist and total butterfly abundance were negatively associated with the percent cover of bare ground, total butterfly abundance was positively associated with the percent cover of forbs, and habitat-generalist butterfly abundance was positively associated with floral resource availability. Areas managed with fire, grazing, or a fire/grazing combination all maintained equally species rich, yet compositionally different, butterfly communities. Butterfly abundance increased as time since burn increased. The percent cover of warm season grasses and bare ground decreased while the cover of cool season grasses, forbs, and litter depth increased with time since burn. We used path analysis to examine direct and indirect effects of burning. For habitat-specialist species abundance path models, the total indirect effects of time since burn through floral resources, warm season grass cover, or bare ground were stronger relative to the direct effect of time since burn. The indirect pathway through bare ground had higher relative strength than other indirect paths in the models for habitat-specialist species. For the habitat-generalist species path models, the direct effect of time since burn was stronger relative to the indirect effects. Because of this variation in butterfly species responses to different management practices, we do not recommend a single type of management that would benefit all species or even all species within habitat-specialist or habitat-generalist habitat guilds. Our data illustrate the profound effects, both direct and indirect, of fire on grassland butterfly abundance.

Download or read book Breeding Bird Plant and Arthropod Responses to Restoration and Management of Riparian Conservation Easements in the Iowa River Corridor East central Iowa written by Thomas Jefferson Benson and published by . This book was released on 2003 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: As interfaces between terrestrial and aquatic systems, riparian areas are important for many wildlife species. Like other natural communities in the Midwest, however, riparian areas have been greatly altered. Recently, habitat restoration through farm-bill and flood-mitigation programs, such as the Wetlands Reserve Program (WRP) and Emergency Wetlands Reserve Program (EWRP), has substantially increased the amount of riparian habitat in the midwestern United States. Working on restored areas in the Iowa River Corridor of east-central Iowa, I assessed the effects of management on vegetation structure and composition, the abundance and biomass of arthropods, and bird use and reproductive success. For a better understanding of important habitat features, I also investigated the relationships between vegetation and arthropod variables and bird use. Lastly, I quantified the extent of alteration of the Iowa River Corridor since settlement, the effects of restoration on the landscape, and the contribution of restored areas to bird populations. Restoration of riparian grasslands provided habitat for many bird species, including 9 grassland or wetland species of conservation concern. Although burning may have negatively influenced density of some bird species by removing residual vegetation and decreasing food resources, disking led to increased density of several species, and increased species richness and conservation value. Disking decreased cover of grasses, and increased forb cover; it also increased abundance and biomass of potential arthropod food resources. Dickcissels, in particular, appeared to respond positively to the changes brought about by disking. Nest success in these riparian habitats was generally low. Burning and disking, however, appeared to have positive effects on reproductive success, possibly by affecting the habitat use or foraging efficiency of predators. Although vegetation variables explained variation in bird density, species richness, and conservation value, adding arthropod abundance improved most models. Restored riparian grasslands in the Iowa River Corridor provided habitat for several bird species of conservation concern. Accounting for the influences of vegetation and arthropods, and using burning and disking as management tools, however, can likely increase the conservation benefits of these habitats for birds in the Iowa River Corridor and other riparian systems throughout the Midwest.

Download or read book Grazing and Haying Effects on Habitats of Upland Nesting Birds written by Leo M. Kirsch and published by . This book was released on 1986 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Indirect Effects of Wind Energy Development on Grassland Bird Habitat Use and Reproductive Success written by Anika Mahoney and published by . This book was released on 2015 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind energy development is rapidly expanding in grassland habitat, but potential indirect effects to wildlife populations are largely unknown. As observed in other types of human development, wind energy infrastructure could alter plant and invertebrate communities, change soil and hydrology, generate visual and aural noise, and increase human activity in previously undeveloped areas. These changes to habitat can indirectly affect wildlife in many ways, for example, by altering trophic interactions or habitat use. Native grasslands in the United States have undergone extensive habitat loss and degradation, and subsequently, many grassland-associated bird species have experienced precipitous population declines. We assessed the indirect effects of wind energy development on the habitat use and reproductive success of two grassland songbirds, Horned Lark (Eremophila alpestris) and McCown’s Longspur (Rhynchophanes mccownii) in Wyoming. We modeled bird density in 2012 as a function of habitat characteristics and wind energy development. We estimated bird density at two scales of development- between two wind farms and two undeveloped sites, and within wind farms as a function of proximity to nearest wind turbine. Despite a general characterization of Horned Larks as disturbance-tolerant, the numbers of Horned Lark within wind farms were substantially lower near turbines. McCown’s Longspur numbers were higher near turbines in areas with high heterogeneity in bare ground, but showed no variation with heterogeneity of bare ground far from turbines. These responses indicate potential avoidance of turbines by Horned Lark, and a difference in habitat associations by McCown’s Longspur near turbines. We evaluated nest placement of Horned Lark and McCown’s Longspur in 2012 in relation to turbine proximity on three wind farm plots. The mean turbine proximity at each plot was no different than predicted by a random distribution, and the turbine-proximity values of observed nests were uniformly distributed, indicating no evidence of displacement of nests from turbines. Although Horned Lark occur in lower numbers near turbines, there was no evidence of avoidance of turbines in nest placement. We assessed the reproductive success of Horned Lark and McCown’s Longspur in 2011 and 2012 on 3 wind farms and 2 undeveloped sites. We evaluated multiple indices of nesting productivity (clutch size, size-adjusted nestling mass, daily nest survival rate, and number of young fledged per successful nesting attempt), and modeled these reproductive metrics as a function of habitat and wind energy development. We quantified wind energy development using several measures of disturbance: turbine proximity, turbine density, distance to developed edge, and the amount of developed and reclaimed area within the neighborhood of the nest, and identified which measure was most predictive of reproductive success. Turbine density was repeatedly the measure of wind energy development most strongly associated with avian reproductive success. The nestling mass and, in 2011, nest survival of Horned Lark were negatively related to increasing turbine density. Annual variation in the effect of infrastructure on nest survival indicates that infrastructure may only have negative consequences in correlation with other biotic or abiotic events, e.g., during years of high predator abundance. The nest survival of McCown’s Longspur was most strongly predicted by nest site and neighborhood habitat variables and turbine density within 1 km of the nest. Likelihood of McCown’s Longspur nest survival decreased from 54% to 5% as vegetation density increased, and the inclusion of turbine density and grassland area in the neighborhood amplified this relationship resulting in a 28% to

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 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 Post fire Successional Effects on Breeding Grassland Birds in Mesquite Savanna Habitats of the Texas Rolling Plains written by Stephanie L. Lee and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: North American grasslands and grassland birds have declined drastically due to habitat degradation by fire suppression (i.e., woody encroachment), fragmentation, and conversion to croplands. A better understanding is needed of the relationships among disturbance regimes (e.g., fire), resultant vegetation changes, and grassland bird communities to effectively manage remaining grasslands and grassland birds. I assessed the relationship between post-fire succession, and mean relative abundance and nesting ecology of breeding grassland birds (i.e., nest-site selection and nest success) in mesquite-dominated rangeland of the Texas Rolling Plains, where prescribed fire is used as a tool to manage shrub encroachment. Brush cover, grass cover, and visual obstruction generally increased with post-fire succession, and bare ground decreased with post-fire succession. Species richness, grasshopper sparrows (Ammodramus savannarum), Cassin's sparrows (Aimophila cassinii), and dickcissels (Spiza americana) responded positively to post-fire succession, and lark sparrows (Chondestes grammacus) responded negatively to post-fire succession.; abundance of these avian groups was low on the control sites. During 2004-2005, 90 grassland bird nests were monitored. I found conflicting results for vegetation parameters important to nest site selection and probability of nest success. For all species except lark sparrows, nest-site location was positively associated with visual obstruction and with grass or forb cover. However, the probability of nest success increased with lower visual obstruction, bare ground cover, or grass cover. Grassland bird abundance, nest-site location, and nest success had differing associations with vegetation variables. These results suggest that to effectively manage remaining grasslands for sustainable breeding grassland bird populations, managers should engage in practices that keep habitat in multiple vegetative successional stages.

Download or read book The Effects of Habitat Management on Grassland Birds in the Northern Tallgrass Prairie written by Jerry Sterling Cole (Jr.) and published by . This book was released on 2016 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluating the Success of Prairie Restorations in Southwest Illinois in Providing Suitable Habitat for Prairie Birds written by Aaron M. Alexander and published by . This book was released on 2017 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tallgrass prairie is one of the most endangered ecosystem types in North America, as over 99% of historic tallgrass prairie has been lost, even though it is one of the younger ecosystem types. The main factors behind the dramatic loss of tallgrass prairie include conversion to agriculture or development and a suppression of the natural fire regime in these grassland areas. Any natural prairies left are often too small and isolated to serve as viable habitat for grassland-dependent species, making the efforts at restoring these areas critical. Prairie restoration is crucial to grassland-dependent species because it increases the area of suitable habitat. Once a prairie restoration has taken place, it must be managed and evaluated to keep succession at bay and to help ensure that all restoration objectives have been met. Illinois has less than 1% of natural tallgrass prairie remaining, causing the grassland bird communities of the state to experience severe population declines within their ranges. Grassland bird species are important pollinators and dispersers of plants, and are under significant decline, which make them important priorities for conservation efforts. Birds in general are good ecological indicators of restoration success as they can be seen and heard easily, they have specific habitat requirements, and they are often the first animals to reach a restoration effort. Illinois has seen several prairie restoration attempts take place within the last 40 years, but very few studies have been conducted to assess the relative success or failure of these restoration efforts. The objectives of this study are to (1) examine temporal trends in the avian community composition, richness, and diversity among prairie restorations at The Nature Institute, (2) to test whether these trends are heading in the direction of the old growth reference prairie, and (3) to investigate which habitat attributes are the best predictors of the presence and abundance of prairie bird species. I hypothesize that (1) the restorations are on track to attain the bird community composition and diversity of an old growth prairie; (2) changes in vegetation structure over time during restoration provide suitable habitat for particular species of prairie birds. Five 20 m radius sampling plots were established in each of the study sites and utilized for both avian and vegetation sampling. Avian sampling took part in two periods, one spanning the entire avian breeding season from late May into early August, and the other corresponded with avian migration and lasted from September into late October. Plots were divided into regular distance intervals (0-5 m, 6-10 m, 11-15 m, 16-20 m) and all birds within as well as those flying over and outside of the plot were recorded. Vegetation characteristics (e.g., litter depth, forb coverage, and vegetation height) were measured along a 40 m transect within each study plot. Species richness, Antilog Shannon’s and Simpson’s diversity indices, and density (birds per hectare) for each plot was calculated. Non-metric multidimensional scaling ordination was utilized to visualize patterns within the avian community data and to assess whether or not the restorations were on track to achieve the avian community structure of the old-growth reference prairie. Diversity indices were highest in the youngest restorations before dropping off at the oldest restoration and the reference prairie. Indicator species analysis showed that the northern cardinal, willow flycatcher, indigo bunting, and the ruby-throated hummingbird were indicative of restored prairies less than seven years old, whereas species like the chipping sparrow, common yellowthroat, and the red-winged blackbird signaled older prairie restorations (15-29 years). Field sparrows were found to be indicator species of the old-growth reference prairie used in this study. Non-metric multidimensional scaling showed that each study prairie was different from one another based on their avian communities and that the restorations are not on track to achieve the avian community structure found in the reference prairie. The results of this research will provide valuable information to prairie managers across the region. Results from this study show that small isolated prairie restorations, although good for community outreach and public education on the topic, will not meet objectives related to stopping prairie bird declines in a region. Large and well-connected prairie restorations are ideal for grassland-dependent species when planning out future restoration efforts.

Download or read book Effects of Urbanization and Habitat Quality on the Songbirds of San Diego County Grasslands written by and published by . This book was released on 2017 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grasslands are one of the most threatened and altered ecosystems in the world. These ecosystems are also severely under protected. Grassland songbirds have suffered substantial population declines in response to the loss and degradation of grassland habitats. Previous urbanization studies investigated changes in avian species composition from rural to urban habitats. The results of these studies do not provide insight into effects of urbanization surrounding intact habitat patches. Grassland songbirds are unable to live directly within urban areas due to nesting requirements, however urbanization adjacent to grassland habitats may still influence grassland birds and ecosystems. Humans have had a tremendous effect on California’s native grasslands, which are now one percent of the original ∼9 million ha, and urbanization is the main threat to remaining fragments in San Diego County. My thesis addressed how grassland songbirds are affected by urbanization at varying scales and intensities. I sampled five grassland sites within San Diego County that differed in the intensity of urbanization. Songbird presence, abundance, and reproductive success were quantified. The relative density of grasshoppers, an important food source, was also measured as well as the vegetation structure and composition. A technique for quantifying the amount of urbanization in the landscape surrounding study sites was developed. This technique was designed to be repeatable in any context and does not use arbitrary nomenclature for the varying types of land use. Overall, the results of this study were complicated, sometimes in unexpected ways. As a result, a more nuanced interpretation of the results was needed. I found that the grassland habitats in San Diego County are idiosyncratic in nature likely due to the spatial patterns of development and land use history. Urbanization in the landscape was found to be correlated with higher quality grassland habitat. There was also a positive correlation among both grassland bird nesting success and abundance and urbanization. These data also show that habitat composition and structure are important for grassland songbirds regardless of urban intensity in the landscape. Finally, it is clear that some avian species will likely avoid urbanized areas even if they contain patches of high quality habitat.

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 Effects of Natural Gas Well Development on Songbird Reproductive Success in Mixed grass Prairies of Southeastern Alberta written by Jenny Yoo and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grassland songbird populations have experienced declines due to habitat loss. In Canada, gas well development continues to fragment and disturb prairie habitat. From 2010-2012, I monitored a total of 374 nests in mixed-grass prairie located in southeastern Alberta. I estimated the probabilities of nesting success relative to gas well infrastructure to test for effects on reproductive success. There was very little effect of well pads on nesting success, while roads had a greater impact. Savannah sparrow and chestnut-collared longspur clutch sizes and fledgling numbers per nest were lower near gas well pads and cattle water sources, suggesting lower quality habitat in these areas. Large-sized predators occurred less in areas with older well pads. Concentrations of new well pads may have greater effects on chestnut-collared longspur reproductive success. Minimizing habitat disturbance surrounding gas well pads, and reducing abundance of roads, should minimize impacts on reproductive success for most grassland songbirds.