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 Responses of Grassland Birds to Patch burn Grazing in the Flint Hills of Kansas written by Amy Nicole Erickson and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Grassland birds are declining throughout their native range. The Flint Hills of eastern Kansas and Oklahoma contain large tracts of tallgrass prairie, but intensification of agricultural practices may be contributing to ongoing population declines. Common rangeland management practices include annual burning coupled with heavy grazing by cattle. This system, known as intensive early stocking and burning, promotes homogeneous utilization of forage by cattle but may not provide habitat for some grassland bird species. Patch-burn grazing is an alternative management system that aims to restore heterogeneity on rangelands by recreating the fire-grazing interaction that would have historically occurred throughout the Great Plains. From 2011-2013, we examined responses of grassland birds to traditional rangeland management and patch-burn grazing by conducting vegetation surveys, line transect surveys, and nest monitoring on privately-owned pastures in Chase County and Greenwood County, Kansas. Vegetative heterogeneity was higher on patch-burned pastures, with unburned patches having higher visual obstruction and less bare ground. Densities of grassland birds differed by species and among habitat strata. Unburned patches on patch-burned pastures were associated with increased densities of Dickcissels (Spiza americana), Eastern Meadowlarks (Sturnella magna) and Grasshopper Sparrows (Ammodramus savannarum). Henslow's Sparrows (A. henslowii) were only detected on patch-burned pastures. Nest survival of grassland songbirds was similar among management systems but varied by year. Probability of nest parasitism by Brown-headed Cowbirds (Molothrus ater) varied among years and between treatments for Dickcissels and Grasshopper Sparrows, with overall lower rates on burned areas and during drought years. For Dickcissels and Grasshopper Sparrows, there was a significant reduction in host clutch size between parasitized versus unparasitized nests. Overall, nest survival of grassland songbirds in managed rangelands was low. Patch-burn grazing improved rangeland conditions and provided habitat for more species of birds, but did not increase nest survival. Drought conditions in 2012 and 2013 may have influenced the results of this study, as many landowners were unable to burn as planned. Further study is needed to determine underlying factors driving variation in nest success and parasitism rates for grassland birds, particularly on private lands which make up the vast majority of remnant tallgrass prairies.

Download or read book Eastern Tallgrass Prairie Management and Its Impact on Grassland Birds written by Heather Herakovich and published by . This book was released on 2019 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: The majority of tallgrass prairie has been converted to agriculture over the past two centuries, making it one of the most threatened ecosystems globally. Agricultural conversion of prairie fragmented the landscape, causing declines and local extirpation of many grassland birds. Restoration projects have sought to increase the quality and size of prairie fragments by converting cultivated land back to prairie through revegetation and management with prescribed fire, hypothetically increasing breeding habitat for grassland birds. Bison and other grazers are now being reintroduced to prairie restorations as a final step in the restoration process to increase habitat heterogeneity. The goal of my dissertation was to determine how a recent bison reintroduction at Nachusa Grasslands impacted grassland bird nest success, nest predator composition, and grassland bird detection frequency and to see if it is similar to other studies. I measured daily survivorship rate, visual obstruction of vegetation around nests, and species composition of fourteen species of known avian breeders in areas with and without bison from 2014 to 2018 (Chapter 2). Reduced vegetation obstruction and Brown-headed Cowbird parasitism resulted in decreased nest success overall. Generalist nesters did not differ with respect to any measured variables, including presence of bison. In contrast, facultative and obligate grassland nesting birds occurred at lower nest densities and experienced reduced and more variable nest success in areas with bison. In addition, I constructed artificial nests and placed them at a set density in sites with and without bison and with varying fire frequencies over the same time period (Chapter 3). I found that nest success decreased, and total proportion of depredation events and proportion of Cricetid depredation events increased with prescribed fire. Yearly differences influenced nest success the most and were not related to precipitation during the experiment. I found less nest depredation in the sites with bison, but I found no interaction between fire and grazing. Lastly, I sought to quantify overall species richness and the detection frequency as a proxy for relative abundance of certain grassland bird species that are thought to be impacted by bison grazing (Henslow's Sparrows, Grasshopper Sparrows, Eastern Meadowlarks, Dickcissels, and Brown-headed Cowbirds) from 2016- 2018 (Chapter 4). I used stationary bioacoustics recorders to record the soundscape just after dawn and just before dusk during the summer breeding season in areas with and without bison. I found that species richness and detection frequency of the majority of my target species were not influenced by bison presence. Grasshopper Sparrows were the only species to respond to bison presence and prescribed fire with increase detection frequency in areas burned and grazed. Henslow's Sparrows also showed a species-specific response, but only to prescribed fire, where detection frequency was lower in areas burned. These results are consistent with other research in remnant prairie with both cattle and bison grazing. Site age was the predominant influence on detection frequency of Henslow's Sparrows, Dickcissels, and Eastern Meadowlarks likely due to the vegetation differences in sites that are planted versus remnant sites, with Brown-headed Cowbird abundance only influenced by year. My results suggest that nesting success and detection frequency may be being impacted by bison

Download or read book Rangeland Systems written by David D. Briske and published by Springer. This book was released on 2017-04-12 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is open access under a CC BY-NC 2.5 license. This book provides an unprecedented synthesis of the current status of scientific and management knowledge regarding global rangelands and the major challenges that confront them. It has been organized around three major themes. The first summarizes the conceptual advances that have occurred in the rangeland profession. The second addresses the implications of these conceptual advances to management and policy. The third assesses several major challenges confronting global rangelands in the 21st century. This book will compliment applied range management textbooks by describing the conceptual foundation on which the rangeland profession is based. It has been written to be accessible to a broad audience, including ecosystem managers, educators, students and policy makers. The content is founded on the collective experience, knowledge and commitment of 80 authors who have worked in rangelands throughout the world. Their collective contributions indicate that a more comprehensive framework is necessary to address the complex challenges confronting global rangelands. Rangelands represent adaptive social-ecological systems, in which societal values, organizations and capacities are of equal importance to, and interact with, those of ecological processes. A more comprehensive framework for rangeland systems may enable management agencies, and educational, research and policy making organizations to more effectively assess complex problems and develop appropriate solutions.

Download or read book Prairie Conservation written by Fred B. Samson and published by Island Press. This book was released on 1996-08 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: The area of native prairie known as the Great Plains once extended from Canada to the Mexican border and from the foothills of the Rocky Mountains to western Indiana and Wisconsin. Today the declines in prairie landscape types, estimated to be as high as 99%, exceed those of any other major ecosystem in North America. The overwhelming loss of landscape and accompanying loss of species constitute a real threat to both ecological and human economic health.Prairie Conservation is a comprehensive examination of the history, ecology, and current status of North American grasslands. It presents for the first time in a single volume information on the historical, economic, and cultural significance of prairies, their natural history and ecology, threats, and conservation and restoration programs currently underway. Chapters cover: environmental history of the Great Plains the economic value of prairie prairie types -- tallgrass, mixed grass, shortgrass, wetlands -- and the ecological processes that sustain each type prairie fauna -- invertebrates, fish and other aquatic creatures, amphibians and reptiles, birds, and mammals conservation programs such as the Great Plains Partnership, Canada's Prairie Conservation Action Plan, the U.S. Prairie Pothole Joint Venture, and others The book brings together knowledge and insights from a wide range of experts to describe and explain the importance of prairies and to position them in the forefront of North American conservation efforts. Praire Conservation is an essential reference for anyone interested in prairie ecology and conservation and will play a critical role in broadening our awareness and understanding of prairie ecosystems.

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 Direct and Indirect Effects of Livestock Grazing Intensity on Processes Regulating Grassland Bird Populations written by Tracey N. Johnson and published by . This book was released on 2011 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: In grasslands, grazing by large ungulates can influence vegetation structure, composition, primary productivity, and ultimately, ecosystem functioning. While grazing represents a complex disturbance, grazing intensity largely determines the effects of grazing on vegetation. Structural and compositional changes in the plant community caused by grazing could have bottom-up effects on species and interactions at higher trophic levels. Thus, particular management strategies for domestic livestock in rangeland systems could exert a strong affect on grassland wildlife. Grassland-dependent songbirds may be particularly susceptible to the effects of domestic grazers because they depend on grassland vegetation for foraging and nesting. Domestic livestock may influence grassland-breeding bird populations by affecting settlement decisions, resource availability, or reproductive success. We investigated the effects of grazing intensity on grassland vegetation structure and songbird demography in a northwestern bunchgrass prairie using paddocks with experimentally-manipulated cattle stocking rates. We compared effects of four stocking rates (0, 14.4, 28.8, and 43.2 animal unit months) on songbirds using a randomized complete block design with four replicates of each stocking rate to address hypotheses regarding demography of grassland songbirds. Overall paddock-level vegetation structure decreased and structural heterogeneity of vegetation increased with higher stocking rates, and those effects carried over one-year post-grazing. However, most bird species were able to locate nesting sites with similar vegetation structure regardless of paddock-level effects of stocking rate. The exceptions were western meadowlarks and vesper sparrows; nests of these species in paddocks with higher stocking rates had less vegetative cover. Apparent nest density for grasshopper sparrows was negatively affected by higher stocking rates. Grazing treatment effects on songbird population density were restricted to negative effects of higher stocking rates on savannah sparrows, but this relationship was not observed until the post-treatment year. Songbird community composition differed between control and heavily-grazed paddocks, but diversity was not affected by stocking rate. Nest fates were evaluated to determine whether stocking rate influenced nest survival or cause-specific nest failure. Other variables such as vegetation structure and predator community, date, year, and nest age were included to help clarify which mechanisms might be responsible for differences in nest survival or failure rates among treatments. For our analysis, we introduce the use of a novel software package, McNestimate, to estimate the daily probability of nest survival and failure from specific causes. McNestimate estimates the probability of nest failure from competing causes when the exact dates of failure are unknown using a Markov Chain framework, and incorporates a model selection approach which allows the use of covariates to help identify variables important in explaining variation in the daily probability of nest failure. Nest predation rates increased with the age of the nest and throughout the breeding season, but were not affected by stocking rate. The probability of nest failure from adverse weather declined throughout the season, but the rate of decline depended on year. Nest failure rates due to trampling were higher in paddocks with higher stocking rates, but also depended on the number of days cattle were present during the nesting period. Patterns of overall probability of nest success were driven by predation patterns in the first year, but in the second year were strongly influenced by the chances of weather-related nest failure. Although starvation was not identified as a significant source of nest failure, grazing-induced changes to vegetation structure and composition could influence food availability for breeding songbirds, ultimately affecting the composition of nestling diets and nestling condition. To better understand the relationship between grazing intensity, nestling diet composition, and subsequent effects on nestling condition, we examined the invertebrate composition of nestling fecal samples. All species showed strong preferences for Lepidoptera (moths and butterflies) larvae, and partial preferences for Coleoptera (beetles) and Araneae (spiders). The proportion of preferred prey items was not affected by stocking rate. There were effects of bird species on the proportion of Araneae and Coleoptera and the proportion of Acrididae (short-horned grasshoppers) in the diet of western meadowlark nestlings decreased with high stocking rates. Growth rates for western meadowlarks and vesper sparrows were negatively affected by higher stocking rates. These results suggest that stocking rates can have variable effects on grassland songbird population and nest density depending on each species' habitat requirements. However, negative effects of high stocking rates on nest survival and nestling condition could have consequences for juvenile survival and recruitment. Overall, low-to-moderate stocking rates are likely compatible with many grassland bird species in northwest bunchgrass prairie, and although heavier livestock grazing may help create suitable vegetation structure for some songbird species, high stocking rates may influence grassland songbird diet quality, or have negative effects on nestling condition. We hypothesized that grazing intensity could influence the grassland songbird community through "bottom-up" effects on vegetation, but effects of grazing at different intensities did not translate directly through the food web to influence songbird populations as strongly as lower trophic levels. Processes responsible for changes in community composition such as immigration or emigration may not have had time to ensue during our short-term experiment; alternatively, sufficient spatial or temporal heterogeneity remained in the system, even at the highest grazing intensity, such that grazing-induced changes in lower trophic levels were irrelevant for most songbird species. Our results contribute to understanding grassland songbird demographic responses to different grazing intensities and identify specific mechanisms by which conservation measures for declining grassland bird populations can be improved.

Download or read book Effects of Hayfield Management on Grassland and Songbirds written by Noah G. Perlut and published by . This book was released on 2007 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study provides information on how agricultural management affects the ecology, evolution, and viability of grassland birds. It will help inform landowners, managers, and law-makers about management practices and habitat requirements needed to sustain populations.

Download or read book Direct and Indirect Drivers of Grassland Bird Population Declines and Settlement Decisions Over Broad Spatial and Temporal Scales written by Dylan J. Smith and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many North American bird populations are declining, and of those, grassland bird populations are declining most rapidly, having been reduced by about half since 1970. Such declines are difficult to study, both because grasslands are characterized and maintained by disturbance, and because grassland birds have a high propensity for dispersal. The primary cause for population declines is habitat loss. For example, only ~14% of pre-European colonization eastern tallgrass prairie remains intact. Even where habitat remains, many species continue to decline, and these declines may be due to reductions in reproductive success. One potential cause of these local declines is the encroachment of woody vegetation on grasslands, which for grassland birds reduces the overall amount and degrades the quality of usable habitat. In addition, local demographic changes cause-and are caused by-regional- or continental-scale patterns. Thus, broad spatial approaches are needed to best understand the drivers of demographic change. In my first chapter, I sought to identify whether woody encroachment, via reductions in reproductive success, can explain changes in population abundance. I compiled and analyzed data on nest contents and nest success collected at Konza Prairie Biological station over nearly five decades. Nest success did not change since 1971, but the frequency of Brown-headed Cowbird (Molothrus ater) brood parasitism increased. In addition, grassland obligates were harder hit than species that prefer woodier habitat, supporting the idea that grassland degradation most strongly affects birds that rely on pristine prairie. In chapter 2, I tested alternative mechanisms linking the high degree of climatic variability in the Great Plains to inter-annual fluctuations breeding distribution and local abundance of a common grassland bird species, Grasshopper Sparrows (Ammodramus savannarum perpallidus). I used 11 years of citizen science data from eBird spanning the entire Great Plains to determine whether overwinter mortality, temperature during migration, or precipitation during the preceding year's growing season and vegetation phenology best predicted local abundance. The start date of the growing season and the total precipitation in the preceding year's growing season correlated most strongly with sparrows' interannual settlement decisions. Local abundance was highest in areas where the growing season started before March and where the preceding year's growing season precipitation was low. The drivers of population declines and movement decisions in grassland birds are complex and often indirect or delayed. As grasslands face ongoing anthropogenic threats ranging from agricultural development to fire suppression and climate change, identifying the distributional and demographic responses of grassland birds will be crucial to conserving this declining group of species.

Download or read book Perspectives in Grassland Ecology written by N.R. French and published by Springer. This book was released on 1979-05 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grassland primary production: North American grasslands in perspective. Processes controlling blue grama production on the shortgrass prairie. Analysis of the response of a grassland ecosystem to stress. Grassland biomass trophic pyramids. Patterns of consumption in grasslands. An ecosystem-level tropic-group arthropod and nematode bioenergetics model. Factors influencing imput and output of nitrogen in grasslands. Simulated impact of management practices upon the tallgrass prairie. Data-based, empirical, dynamic matrix modeling of rangeland grazing systems. Principal subsystem Interactions in grasslands.

Download or read book Ecology of the Shortgrass Steppe written by W. K. Lauenroth and published by Oxford University Press. This book was released on 2008-08-28 with total page 537 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecology of the Shortgrass Steppe: A Long-Term Perspective summarizes and synthesizes more than sixty years of research that has been conducted throughout the shortgrass region in North America. The shortgrass steppe was an important focus of the International Biological Program's Grassland Biome project, which ran from the late 1960s until the mid-1970s. The work conducted by the Grassland Biome project was preceded by almost forty years of research by U.S. Department of Agriculture researchers-primarily from the Agricultural Research Service-and was followed by the Shortgrass Steppe Long-Term Ecological Research project. This volume is an enormously rich source of data and insight into the structure and function of a semiarid grassland.

Download or read book Grassland Bird and Arthropod Responses to USDA Filter Strip Characteristics in Southwestern Minnesota written by Nicole Marie Davros and published by . This book was released on 2005 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: The once vast grasslands of the Northern Tallgrass Prairie region have undergone substantial modification since European settlement. Concomitantly, grassland birds have experienced drastic population declines. Since 1996, the United States Department of Agriculture (USDA) has actively promoted conservation buffers through its Continuous Enrollment Conservation Reserve Program (CCRP). A particularly popular buffer practice in the Midwest, filter strips are 6-36 m wide strips of herbaceous vegetation established along waterways to reduce soil erosion and improve water quality. Created in 1997, the Conservation Reserve Enhancement Program (CREP) provides opportunities to widen filter strips and diversify seeding mixtures. Understanding how filter strip design influences bird use of these habitats can provide conservation partners with information on how to better accommodate grassland bird species of concern into management objectives. During 2003 and 2004, 1 sampled 39 filter strips in southwestern Minnesota in order to assess the local- and landscape-level characteristics influencing bird use of USDA filter strips. I also investigated the local-level characteristics influencing arthropod occurrences in filter strips; emphasis was placed on taxa important to breeding bird diets. Arthropod richness, abundance, and drymass were negatively correlated with standing dead vegetation. Filter strip width, vegetation vertical density, and forb cover were not as important in my arthropod models as I had predicted. A nested analysis of local habitat variables showed that filter strip width, standing dead vegetation, forb cover, and vegetation vertical density were important in explaining variation in bird abundance and species richness, but adding arthropod drymass variables improved most models. Separate landscape models showed that bird occurrences were positively associated with herbaceous cover but negatively associated with developed areas and the density of herbaceous habitat edges in the 1 km radius surrounding filter strips. Logistic-exposure models showed that daily survival rates of songbird nests were negatively affected by filter strip width and standing dead vegetation. Adding arthropod information did not improve nest models. Predation was the major cause of nest failure for all nesting species. Though the primary purpose of filter strips will remain soil conservation, several opportunities exist for incorporating grassland bird conservation objectives into filter strip design.

Download or read book Restored Heterogeneity as a Conservation Strategy for Grassland Birds written by Torre James Hovick and published by . This book was released on 2014 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grasslands are inherently dynamic in space and time evolving with frequent disturbance from fire and herbivores. Throughout much of the world, grasslands have been converted and fragmented and many remaining grasslands have become homogenous as a consequence of human actions. As a result, ecosystem function has declined and biodiversity loss has led to decreased ecological services. Of particular concern are highly imperiled grassland birds which have experienced greater population declines than any other habitat associated guild of birds in North America. Conservation efforts that restore heterogeneity to grasslands through the re-coupling of fire and grazing may be an effective strategy for stabilizing or increasing grassland bird populations. We examined Greater Prairie-Chicken (Tympanuchus cupido) ecology, breeding bird community diversity and stability, and non-breeding bird community diversity and patch occupancy in tallgrass prairie with restored structural and compositional heterogeneity. We found that Greater Prairie-Chickens selected for patches with greater time since fire and grazing and that taller vegetation increased nest survival. Additionally, nests that survived were in cooler environments and prairie-chickens displayed fine scale thermal habitat selection as nest sites were nearly 4°C cooler than micro-sites within 2 meters of nests. We found that heterogeneity increased breeding bird community diversity and that increased heterogeneity resulted in greater community stability over time. Finally, non-breeding bird community diversity increased as a result of structural heterogeneity and occupancy modeling revealed that certain species selected for varying patches along a disturbance gradient (i.e, recently disturbed to relatively undisturbed) that resulted from fire and grazing dependent heterogeneity. Our findings add to a growing body of literature supporting the use of fire and grazing to create a shifting grassland mosaic that increases vegetation structural and compositional heterogeneity and maximizes native biodiversity within rangeland ecosystems through the conservation of natural patterns and processes. Additionally, these data provide evidence that variation in grassland structure resulting from the fire-grazing interaction may be important in moderating thermal environments and highlights the complex and interactive effects of restored ecological processes on ecosystems. We recommend future management efforts in rangelands focus on restored disturbance process to increase heterogeneity and improve grassland bird conservation.

Download or read book The Influence of Patch burn Management on the Nesting Ecology of Grassland Birds at the Tallgrass Prairie Preserve Oklahoma written by Roy Thomas Churchwell and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessment of Grassland Ecosystem Conditions in the Southwestern United States without special title written by and published by . This book was released on 2004 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessment of grassland ecosystem conditions in the southwestern United States written by and published by . This book was released on 2004 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Interactive Effects of Annual Climatic Variability and Rangeland Management on the Reproductive Success of Dickcissels Spiza Americana written by Lauren A. Spahr and published by . This book was released on 2017 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grassland songbird populations have declined due to poor rangeland management and habitat fragmentation. Few studies have taken into account variation in climatic conditions in tallgrass prairie systems when determining the factors contributing to songbird reproductive success. During a six year study we measured reproductive success in Dickcissels on five rangeland treatments. We estimated daily survival rates (DSRs) and linked estimates of daily survival to rangeland management type and climate data. DSRs were best predicted by the model including mean temperature, winter season precipitation, and interactions, which had 7.5 times more support than the constant model. Mean annual temperature was negatively correlated with daily survival rates. Thus climate conditions play important roles in the health and stability of grassland songbird populations.