Download or read book Effects of Grassland Restoration on Avian Assemblage Characteristics and Dickcissel Nesting Success in Texas written by Christopher M. Lituma and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The prairies of North America have undergone substantial changes since European settlement in the 1800's, with some estimates suggesting that 96% of the tallgrass prairie has been converted. Multiple factors contributed to reduction in prairie, including: grazing, row-crop farming, depressed fire regimes, and exotic grass species introduction. In Texas, 35% of the historic grassland ecosystems have been either altered or converted. Introduced in the 1940's, exotic grass species such as Bermuda grass (Cynodon sp) have displaced native grass species throughout Texas. Introduced grass species can alter the existing plant communities degrading habitat for birds and other animals. Grassland birds are declining faster than any other bird group within North America; due in part to a reduction in suitable breeding habitat. I addressed this issue by comparing nesting success of grassland birds between exotic grass sites and restored native grass sites in the blackland prairie region of east-central Texas during 2007-2008 breeding seasons. I conducted point counts and nest searching from March - July. Point count data indicate no difference in species richness between sites. Dickcissel (Spiza americana) nests represented 89% of the nests found (n = 104). Dickcissel abundance was 44% higher in restored sites and 76% of nests were located in restored sites. Daily survival (DSR) for dickcissels in restored sites was 0.895 (SE = 0.013) and for exotic sites was 0.930 (SE = 0.017). I used an independent samples t-test to compare mean nest height, which was 56% higher in restored sites than exotic sites (n = 83, x bar = 38.0 cm "1.90; x bar = 15.2 cm plus/minus 2.19, df = 81, t = -6.31, P = 0.001), and mean nest substrate height which was 58% higher in restored sites than in exotic sites (n = 83, x bar = 118.8 cm " 6.50; x bar = 46.5 cm " 4.77, df = 81, t = -6.08, P = 0.001). Although dickcissel abundance was greater in restored sites than exotic sites, their observed nesting success and DSR was lower in restored sites. This is indicative of an ecological trap, which occurs when an organism is attracted to a habitat that negatively impacts the organism. Some research suggests that restored fields in other states are acting as traps for dickcissels, and according to my results restored sites I sampled may also be acting as ecological traps for dickcissels in Texas.
Download or read book Nesting Success of Dickcissel Spiza Americana and Non breeding Grassland Bird Use of Northwest Arkansas Remnant and Restored Tallgrass Prairies written by Alyssa Lauren DeRubeis and published by . This book was released on 2019 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dwindling populations of North American grassland birds are linked to habitat loss. Tallgrass prairie only covers 3% of its pre-settlement-era range. Small-scale restoration projects attempt to increase acreage for prairie avifauna, and while some breeding grassland species are present at these sites, nesting success and non-breeding use are still largely unknown. Both life history aspects are required for effective grassland bird conservation. My first objective was to access nest success of the Dickcissel (Spiza americana) at two remnant and two restored tallgrass prairies in Northwest Arkansas. From May-August 2017 and 2018, I found 114 nests that I monitored to determine ultimate fate. I selected vegetative characteristics collected at nest and random sites combined with site-level variables to inform a logistic exposure model. Mean nest success was 8.5%, which varied by site but appeared unaffected by restoration status. Excluding predator presence, the most important predictors of nest success were site size size and brood parasitism. Prairie Kingsnake (Lampropeltis calligaster) was the primary nest predator. My second objective was to identify field site characteristics and vegetation use by non-breeding grassland-obligate birds in two remnant and three restored tallgrass prairies in Northwest Arkansas. Between September 2017 and May 2018, I tallied 44 species. Only eight species were grassland-obligate, but this assemblage accounted for about half of all detections. Grassland-obligate diversity was similar across seasons and between sites, except for a small isolated restored prairie which hosted much lower diversity. Dickcissel and Sedge Wren (Cistothorus platensis) detection rates increased significantly with distance to woody edge, indicating area sensitivity. Some species used primarily grass and forb, others utilized burned areas, and Le Conte's Sparrow (Ammodramus lecontei) frequented shrubs. Northwest Arkansas' remnant and restored tallgrass prairies are valuable for nesting Dickcissel and a suite of non-breeding grassland birds. Special consideration for maintaining large parcels with fire that are distant from paved roads should be given for breeding Dickcissel. Acquiring large parcels and maintaining a shifting vegetation mosaic while retaining some woody vegetation could satisfy diverse habitat preferences for non-breeding grassland avifauna.
Download or read book Nesting Ecology of Dickcissels on Reclaimed Surface mined Lands in Freestone County Texas written by Thomas Pingul Dixon and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface mining and subsequent reclamation often results in the establishment of large areas of grassland that can benefit wildlife. Grasslands have declined substantially over the last 150 years, resulting in declines of many grassland birds. The dickcissel (Spiza americana), a neotropical migrant, is one such bird whose numbers have declined in the last 30 years due to habitat loss, increased nest predation and parasitism, and over harvest (lethally controlled as an agricultural pest on its wintering range in Central and South America). Reclaimed surface-mined lands have been documented to provide important breeding habitat for dickcissels in the United States, emphasizing the importance of reclamation efforts. Objectives were to understand specific aspects of dickcissel nesting ecology (i.e., nest-site selection, nest success, and nest parasitism, and identification of nest predators) on 2 spatial scales on TXU Energy's Big Brown Mine, near Fairfield, Texas, and to subsequently provide TXU Energy with recommendations to improve reclaimed areas as breeding habitat for dickcissels. I examined the influence of nest-site vegetation characteristics and the effects of field-level spatial factors on dickcissel nesting ecology on 2 sites reclaimed as wildlife habitat. Additionally, I developed a novel technique to identify predators at active nests during the 2003 field season. During 2002-2003, 119 nests were monitored. On smaller spatial scales, dickcissels were likely to select nest-sites with low vegetation, high densities of bunchgrasses and tall forbs, and areas with higher clover content. Probability of nest success increased with nest heights and vegetation heights above the nest, characteristics associated with woody nesting substrates. Woody nesting substrates were selected and bunchgrasses were avoided. Oak (Quercus spp.) saplings remained an important nesting substrate throughout the breeding season. On a larger scale, nest-site selection was likely to occur farther from wooded riparian areas and closer to recently-reclaimed areas. Nest parasitism was likely to occur near roads and wooded riparian areas. Results suggest reclaimed areas could be improved by planting more bunchgrasses, tall forbs (e.g., curly-cup gumweed [Grindelia squarrosa] and sunflower [Helianthus spp.]), clover (Trifolium spp.), and oaks (a preferred nesting substrate associated with higher survival rates). Larger-scale analysis suggests that larger tracts of wildlife areas should be created with wooded riparian areas comprising a minimal portion of a field's edge.
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 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 Effects of Landscape Characteristics on Nesting Ecology of Cavity nesting Birds written by Sara Harrod and published by . This book was released on 2014 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Effect of Habitat Fragmentation on Grassland nesting Birds in Southwestern Missouri written by Maiken Winter and published by . This book was released on 1998 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Habitat loss and fragmentation on the breeding grounds appears to be a major cause of the apparent decline of many North American bird species. Habitat fragmentation can decrease bird populations through decreases of patch size, increase of edge habitat, and isolation of habitat fragments. These effects of habitat fragmentation have been well documented in forest-nesting birds. However, grassland-nesting birds are experiencing even greater and more consistent population declines, and the reasons for these declines are still poorly understood. Factors that can potentially influence density and nesting success of grassland-nesting birds on their breeding grounds can act at three spatial scales: within-patch scale (vegetation structure and management regime), local scale (patch size and proximity to edge habitat), and landscape scale (habitat surrounding the patch). Between 1995 and 1997 I investigated how factors on each of these three spatial scales affected density and nesting success of grassland-nesting birds in 13 fragments of native tallgrass prairie in southwestern Missouri, focusing on two severely declining passerines, the Henslow's Sparrow (Ammodramus henslowii) and the Dickcissel (Spiza americana). The goal of this thesis was not merely to show that environmental factors at different scales affect density and nesting success of grassland birds; the simultaneous measurement of landscape at multiple scales has additionally allowed me to demonstrate an interaction between the factors measured at these different scales, which has not previously been investigated. Further, most studies on the effects of habitat fragmentation on grassland-nesting birds have based their conclusions on census data only, although census data do not reliably indicate how a species is affected by habitat fragmentation. Low litter depth (particularly the result of haying), small patch size, close proximity (
Download or read book Ecology and Conservation of Grassland Birds of the Western Hemisphere written by Peter D. Vickery and published by . This book was released on 1999 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Conservation by Proxy written by Tim Caro and published by Island Press. This book was released on 2010-06-23 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vast scope of conservation problems has forced biologists and managers to rely on "surrogate" species to serve as shortcuts to guide their decision making. These species-known by a host of different terms, including indicator, umbrella, and flagship species-act as proxies to represent larger conservation issues, such as the location of biodiversity hotspots or general ecosystem health. Synthesizing an immense body of literature, conservation biologist and field researcher Tim Caro offers systematic definitions of surrogate species concepts, explores biological theories that underlie them, considers how surrogate species are chosen, critically examines evidence for and against their utility, and makes recommendations for their continued use. The book clarifies terminology and contrasts how different terms are used in the real world considers the ecological, taxonomic, and political underpinnings of these shortcuts identifies criteria that make for good surrogate species outlines the circumstances where the application of the surrogate species concept shows promise Conservation by Proxy is a benchmark reference that provides clear definitions and common understanding of the evidence and theory behind surrogate species. It is the first book to review and bring together literature on more than fifteen types of surrogate species, enabling us to assess their role in conservation and offering guidelines on how they can be used most effectively.
Download or read book Handbook of Field Methods for Monitoring Landbirds written by and published by . This book was released on 1993 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Managing Habitat for Grassland Birds written by David W. Sample and published by . This book was released on 1997 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book PRAIRIEMAP a GIS Database for Prairie Grassland Management in Western North America written by and published by . This book was released on 2003 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The PRAIRIEMAP web site (http://prairiemap.wr.usgs.gov) contains links to partners, documentation of the data, and a directory of GIS data that can be downloaded.
Download or read book The Desert Grassland written by Mitchel P. McClaran and published by University of Arizona Press. This book was released on 2023-05-23 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mixed grass and shrub vegetation known to scientists as desert grassland is common to the basins and valleys that skirt the mountain ranges throughout southwestern North America, extending from Arizona, New Mexico and Texas down through thirteen Mexican states. This variegated ground cover is crucial to life in an arid environment. The Desert Grassland offers the most comprehensive study to date of these flora and the rich biotic communities they support. Leading experts in geography, biology, botany, zoology, and geoscience present new research on the desert grassland and review a vast amount of earlier work. They reveal that present-day grasses once grew in the ice-age forests that existed in these areas before the climate dried and the trees vanished and how the intensity and frequency of fire can influence the plant and animal species of the grassland. They also document how the influence of humans—from Amerindians to contemporary ranchers, public land managers, and real estate developers—has changed the relative abundance of woody and herbaceous species and how the introduction of new plants and domesticated animals to the area has also affected biodiversity. The book concludes with a review of the attempts, both failed and successful, to reestablish plants in desert grasslands affected by overgrazing, drought, and farm abandonment. Meticulously researched and copiously illustrated, The Desert Grassland is a major contribution to ecological literature. For advanced lay readers as well as students and scholars of history, geography, and ecology, it will be a standard reference work for years to come.
Download or read book An International Borderland of Concern written by D. M. Leslie and published by . This book was released on 2016 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt:
