Download or read book Drivers of Vegetation Response to Interactive Effects of Disturbance in a Sagebrush Steppe written by Lauren Cathleen Connell and published by . This book was released on 2018 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Globally, vegetation structure and patch variability in grasslands and savannas are strongly driven by natural disturbance regimes. These disturbances influence height and cover of herbaceous and woody plants, and often within a variable spatio-temporally regime that results in a heterogeneous landscape. In North America, semi-arid rangelands include grasslands and sagebrush (Artemisia spp.)-dominated shrublands that evolved with spatially and temporally variable disturbance regimes of wildfire, large ungulate herbivory, and colonial burrowing mammals. Moreover, interactions among multiple disturbances, including wildfire, herbivory by wild and domestic ungulates and colonial burrowing mammals, are driving forces of plant community structure and composition. The effects of these multiple, interactive disturbances are particularly less understood in shrubland-grassland ecotone regions, where divergent climate regimes, disturbance-sensitive vegetation communities, and historic disturbance regimes are juxtaposed and interact to create unique ecosystem responses. My study objectives were thus designed to investigate the effects of multiple, interactive disturbances and their implications for livestock and wildlife management. I addressed these topics in the Thunder Basin National Grassland in northeast Wyoming, U.S.A. In Chapter 1, I investigate the separate and interactive effects of livestock, native ungulates, fire, and small mammals on vegetation structure through a three-tiered, large-scale manipulative experiment. I used nested grazing exclosures to isolate the effects of herbivory from livestock, wild ungulates, or small mammals within areas affected by either historical wildfire, black-tailed prairie dog (Cynomys ludovicianus) colonies, or neither disturbance. I replicated this sampling design four times. I evaluated the interactive effects of herbivory and historical disturbance on vegetation structure by quantifying vegetation height, visual obstruction, shrub density, shrub canopy, and shrub leader growth. The exclusion of wild ungulates and lightly-to-moderately stocked livestock for two years did not affect herbaceous vegetation structure, shrub density, or shrub canopy cover. Maximum vegetation height, visual obstruction, heights of grasses and forbs, and shrub density were all negatively affected by prairie dogs. Both wildfire and black-tailed prairie dogs had lower canopy cover of shrubs and Wyoming big sagebrush, when compared to undisturbed sites. Shrub leaders experienced over 3-times more browsing on prairie dog colonies, when compared to undisturbed areas and the combined presence of livestock and native ungulates on prairie dog colonies caused significantly more leader browsing than in the presence of native ungulates alone. In Chapter 2, I assessed the effects of prairie dog herbivory on forage in a northern mixed-grass prairie. Black-tailed prairie dogs have high dietary overlap with livestock, which can cause forage-centric conflicts between agriculture and conservation. Research suggests prairie dogs can enhance forage quality, but it remains unclear how the strength of trade-offs between quality and quantity varies throughout the growing season, or the degree to which increased forage quality is caused by altered species composition versus altered plant physiology. I collected samples on prairie dog colonies and at sites without prairie dogs during June, July, and August 2016 – 2017 for forage quality, and August 2015 – 2017 for biomass. I collected both composite samples of all herbaceous species and also samples of western wheatgrass ( Pascopyrum smithii [Rydb.] Á. Löve) to isolate mechanisms affecting forage quality. Across years and plant sample types, crude protein, phosphorus, and fat were greater and neutral detergent fiber was lower on prairie dog colonies than at sites without prairie dogs. The effects of prairie dogs on forage quality persisted throughout the season for western wheatgrass samples. Across years, aboveground biomass did not differ significantly between prairie dog colonies and sites without prairie dogs and the effects of prairie dogs on herbaceous biomass were significantly influenced by spring precipitation. My results demonstrate season-long enhanced forage quality on prairie dog colonies due to both compositional and phenological shifts associated with prairie dog herbivory. Across years, enhanced forage quality may help to offset reductions in forage quantity for agricultural producers. In Chapter 3, I evaluated the use of conspecific acoustic signals as a potential management tool for prairie dogs. Black-tailed prairie dogs are a major driver of vegetation structure and heterogeneity in northeastern Wyoming, in addition to being highly influential on forage quality and production. The management of prairie dogs in this region is a great priority by the U.S. Forest Service and private landowners and thus I sought to explore the influence of acoustic signals on prairie dog behavior and its fitness implications. Researchers have demonstrated cues of conspecifics including acoustic signals can be successfully used in the conservation and management of avian species but it has rarely, if ever, been applied to free-roaming small mammals. The black-tailed prairie dog is a colonial, small mammal whose gregarious vocalizations create fitness benefits of group vigilance against predation and increased foraging time.
Download or read book Disturbance Vegetation Co occurrence and Human Intervention as Drivers of Plant Species Distributions in the Sagebrush Steppe written by Fiona Claire Schaus Noonan and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Changes in fire regimes, invasive species dynamics, human land use, and drought conditions have shifted important plant species in the Northern Great Basin (NGB)—including big sagebrush (Artemisia tridentata ssp.), conifers (e.g., Juniperus spp.) and invasive annual grasses (e.g., Bromus tectorum). Characterizing how these overlapping disturbances influence species distributions is critical for land management decision-making. Previous research has explored the individual effects of drought, wildfire, restoration, and invasive species on sagebrush steppe communities, but the specific effects of these disturbances in context with one another remain poorly understood at a landscape scale. To address this gap, I constructed multilevel conditional autoregressive (CAR) species distribution models (SDMs) to map the distributions of big sagebrush, juniper, and cheatgrass on lands managed for grazing in the NGB, both with and without a history of fire. These models illuminate the concurrent influences of species co-occurrences, drought, wildfire characteristics (e.g., fire size, time since fire, and number of fires), and restoration treatments. For all SDMs, results indicate that species co-occurrence exhibits the strongest effect—between 1.23 and 19.2 times greater than the next strongest predictor—on all species’ probability of occurrence, suggesting that vegetation co-occurrence meaningfully influences landscape-scale species distributions. In portions of the NGB both with and without historical fire, number of fires and maximum vapor pressure deficit (VPD) also exert substantial influence on the likelihood of species presence, and results indicate that restoration treatments have broadly met desired outcomes for both sagebrush and juniper Narrowing down to only areas that have previously burned, however, models do not support the efficacy of post-fire restoration. All versions of the SDMs, which rely on Bureau of Land Management-administered grazing allotments as a spatial varying intercept, also explicitly point to the differential influence of long-term management regimes on species distributions. These model predictions capture post-disturbance vegetation outcomes under changing fire, climate, and invasive species regimes and in the context of human decision-making, in turn defining a plausible ecological space as these disturbance and management processes play out into the future."--Boise State University ScholarWorks.
Download or read book Drivers of Plant Community Dynamics in Sagebrush Steppe Ecosystems written by Michael D. Reisner and published by . This book was released on 2011 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sagebrush steppe ecosystems are one of the most widespread but endangered ecosystems in North America. A diverse array of human-related stressors has gradually compromised these ecosystems' resilience to disturbance and invasion by Bromus tectorum (cheatgrass). The role of the foundational shrub Artemisia as a driver of herbaceous community structure and dynamics during this degradation process is poorly understood. Many of the individual factors driving B. tectorum invasions are well documented. However a predictive understanding of the relative importance of complex, interacting factors in the causal network of simultaneously occurring processes determining invasibility has proven elusive. I examined these issues at the landscape level across 75 sites capturing a range of soil and landscape properties and cattle grazing levels similar to those found across the Great Basin. Cumulative cattle herbivory stress levels were a predominant component of both the overlapping heat and water stress gradients driving the structure of Artemisia interactions with herbaceous species. Consistent with the stress gradient hypothesis, Artemisia facilitation of herbaceous species was most frequent and strongest at the highest stress levels, and competition was most frequent and strongest at the lowest stress levels. The two species with the highest competitive response abilities, Elymus elymoides and Poa secunda, showed the strongest facilitation at the upper limits of their stress tolerances. The structure of Artemisia interactions with the invasive B. tectorum was strikingly different than those with native bunchgrasses. Artemisia interactions with native bunchgrasses shifted from competition to facilitation with increasing heat, water, and herbivory stress, but its interactions remained competitive with B. tectorum along the entire stress gradient. Shifts in the structure of interactions between Artemisia and native bunchgrasses were associated with both an increase and decrease in community compositional and functional stability. I report the first evidence of native species facilitation decreasing community invasibility. Artemisia facilitation increased native bunchgrass composition, which reduced the magnitude of B. tectorum invasion in under-shrub compared to interspace communities. This decreased invasibility did not translate into lower invasibility at the community level because of the limited spatial scale over which such facilitation occurs. Artemisia facilitation increased community compositional and functional stability at intermediate stress levels but decreased community stability at high stress levels. Facilitation became a destabilizing force when native bunchgrass species became "obligate" beneficiaries, i.e. strongly dependent on Artemisia facilitation for their continued persistence in the community. Structural equation modeling assessed the structure of the causal network and relative importance of factors and processes predicted to drive community invasibility. The linchpin of ecosystem invasibility was the size of and connectivity between basal gaps in perennial vegetation, driven by shifts in the structure and spatial aggregation of the native bunchgrass community. Landscape orientation and soil physical properties determined inherent risk to invasion. Resident bunchgrass and biological soil crust communities provided biotic resistance to invasion by reducing the size of and connectivity between basal gaps and thereby limiting available resources and reducing safe sites for B. tectorum establishment. High levels of cattle grazing reduced ecosystem resilience by reducing native bunchgrass and biological soil crust abundance and altering bunchgrass community composition and facilitated B. tectorum invasion. Conserving and restoring resilience and resistance of these imperiled ecosystems will require reducing cumulative stress levels. As global climate change increases heat and water stress, reducing cumulative cattle grazing intensities by altering utilization rates and/or seasons of use may be the only effective means of accomplishing these goals.
Download or read book The Solitary Bees written by Bryan N. Danforth and published by Princeton University Press. This book was released on 2019-08-27 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most up-to-date and authoritative resource on the biology and evolution of solitary bees While social bees such as honey bees and bumble bees are familiar to most people, they comprise less than 10 percent of all bee species in the world. The vast majority of bees lead solitary lives, surviving without the help of a hive and using their own resources to fend off danger and protect their offspring. This book draws on new research to provide a comprehensive and authoritative overview of solitary bee biology, offering an unparalleled look at these remarkable insects. The Solitary Bees uses a modern phylogenetic framework to shed new light on the life histories and evolution of solitary bees. It explains the foraging behavior of solitary bees, their development, and competitive mating tactics. The book describes how they construct complex nests using an amazing variety of substrates and materials, and how solitary bees have co-opted beneficial mites, nematodes, and fungi to provide safe environments for their brood. It looks at how they have evolved intimate partnerships with flowering plants and examines their associations with predators, parasites, microbes, and other bees. This up-to-date synthesis of solitary bee biology is an essential resource for students and researchers, one that paves the way for future scholarship on the subject. Beautifully illustrated throughout, The Solitary Bees also documents the critical role solitary bees play as crop pollinators, and raises awareness of the dire threats they face, from habitat loss and climate change to pesticides, pathogens, parasites, and invasive species.
Download or read book Invasive Species in Forests and Rangelands of the United States written by Therese M. Poland and published by Springer Nature. This book was released on 2021-02-01 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book describes the serious threat of invasive species to native ecosystems. Invasive species have caused and will continue to cause enormous ecological and economic damage with ever increasing world trade. This multi-disciplinary book, written by over 100 national experts, presents the latest research on a wide range of natural science and social science fields that explore the ecology, impacts, and practical tools for management of invasive species. It covers species of all taxonomic groups from insects and pathogens, to plants, vertebrates, and aquatic organisms that impact a diversity of habitats in forests, rangelands and grasslands of the United States. It is well-illustrated, provides summaries of the most important invasive species and issues impacting all regions of the country, and includes a comprehensive primary reference list for each topic. This scientific synthesis provides the cultural, economic, scientific and social context for addressing environmental challenges posed by invasive species and will be a valuable resource for scholars, policy makers, natural resource managers and practitioners.
Download or read book Quantifying Legacy Effects of Managed Disturbance on Sagebrush Steppe Resilience and Diversity written by Julie Ripplinger and published by . This book was released on 2010 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Land-use legacies can affect landscapes for decades to millennia. A long history of shrub management exists in the sagebrush steppe of the Intermountain West where shrub-removal treatments, a type of managed disturbance, have been implemented for over 50 years to reduce sagebrush cover. The assumption behind managed disturbances is that they will increase forage for domestic livestock and improve wildlife habitat. However, the long-term effects of managed disturbance on plant community composition and diversity are not well understood. We investigated the legacy effects of three common types of managed disturbance (chemical, fire, and mechanical treatments) on plant community diversity and composition. We also examined sagebrush steppe resilience to managed disturbance. Based on management assumptions and resilience theory, we expected within-state phase shifts characterized by an initial reduction in biodiversity followed by a return to prior state conditions. We also expected changes in species proportions, characteristic of within-state shifts in state-and-transition models. We also expected an increase in non-native contribution to overall diversity. We found that plant communities experienced a fundamental shift in composition following disturbance, and responded in a flat linear fashion, giving no indication of return to prior community composition or diversity. As expected, we found post-disturbance increases in the number of non-native grass species present. However, native forb species made the largest contribution to altered diversity. Disturbance modified functional group composition, so contrary to our expectations, within-state changes did not occur as a result of disturbance. Our results indicated that sagebrush steppe plant communities are not resilient to chemical, fire, and mechanical treatments, and subsequent to managed disturbance, community composition tips over a threshold into an alternate stable state.
Download or read book Fire Regimes in Desert Ecosystems Drivers Impacts and Changes written by Eddie John Van Etten and published by Frontiers Media SA. This book was released on 2022-10-14 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Sagebrush Steppe of Montana and Southeastern Idaho Shows Evidence of High Native Plant Diversity Stability and Resistance to the Detrimental Effects of Nonnative Plant Species written by Ryan Lane Quire and published by . This book was released on 2013 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: The premise of this study is that plant diversity is a neglected aspect of the North American sagebrush steppe, a once expansive biome that is now highly degraded. What kind of plant diversity is expected in the sagebrush steppe when it is not regularly physically disturbed? What ecological gradients most affect how plant diversity changes over large spatial scales? The answers to these questions could have implications for invasive plant management and the reclamation and restoration of the sagebrush steppe. Methods included sampling four regions of the sagebrush steppe in the northeastern portion of this biome. The Pryor Mountains, the Charles M. Russell National Wildlife Refuge, and the region of the Yellowstone Plateau were sampled in mostly Montana. These high-native-cover sagebrush sites were compared with those sampled in the Upper Snake River Plains region of southeastern Idaho. One hectare transects were established in high-native cover sagebrush steppe. These were paired with transects established in immediately adjacent disturbance-prone settings (e.g., roadsides) where sagebrush steppe vegetation remained intact. Geographically adjacent transects were sampled where they differed in at least one important ecological attribute. Key findings included that mountain big sagebrush steppe is evolutionarily distinct from Wyoming big sagebrush steppe and that the maximum temperature during the warmest month of the year was an important gradient for shaping species and phylogenetic beta diversity. Geographical proximity also had a large influence on the local species composition. The degree of disturbance also had less of an effect perhaps because of the influence of geography. The effects of physical disturbance were still detectable using descriptive approaches that compared infrequent with frequently disturbed transects. Regardless, native species diversity was distinctly diminished by physical disturbance, which is argued to be evidence that the sagebrush steppe is inherently ecologically stable. The implications of this research include the identification of specific taxonomic groups at and above the species level that may serve as benchmarks for sagebrush steppe reclamation or restoration. Long term stable conditions (infrequent disturbance regimes) are very much required for the successful restoration of the sagebrush steppe.
Download or read book Grasslands and Climate Change written by David J. Gibson and published by Cambridge University Press. This book was released on 2019-03-21 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive assessment of the effects of climate change on global grasslands and the mitigating role that ecologists can play.
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 The Most Important Invasive Plants in Hungary written by Zoltán Botta-Dukát and published by . This book was released on 2008 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Nature of Plant Communities written by J. Bastow Wilson and published by Cambridge University Press. This book was released on 2019-03-21 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a comprehensive review of the role of species interactions in the process of plant community assembly.
Download or read book Carbon Dioxide and Environmental Stress written by Luo Yiqi and published by Elsevier. This book was released on 1999-04-13 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the interactive effects of environmental stresses with plant and ecosystem functions, especially with respect to changes in the abundance of carbon dioxide. The interaction of stresses with elevated carbon dioxide are presented from the cellular through whole plant ecosystem level. The book carefully considers not only the responses of the above-ground portion of the plant, but also emphasizes the critical role of below-ground (rhizosphere) components (e.g., roots, microbes, soil) in determining the nature and magnitude of these interactions. * Will rising CO2 alter the importance of environmental stress in natural and agricultural ecosystems?* Will environmental stress on plants reduce their capacity to remove CO2 from the atmosphere?* Are some stresses more important than others as we concern ourselves with global change?* Can we develop predictive models useful for scientists and policy-makers?* Where should future research efforts be focused?
Download or read book Plant Strategies Vegetation Processes and Ecosystem Properties written by J. Philip Grime and published by John Wiley & Sons. This book was released on 2006-08-11 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plant Strategies, Vegetation Processes, and Ecosystem Properties, Second Edition, is a thoroughly updated and comprehensive new edition of the very successful Plant Strategies and Vegetative Processes, which controversially proposed the existence of widely-recurring plant functional types with predictable relationships to vegetation structure and dynamics. This second edition uses evidence from many parts of the world to re-examine these concepts in the light of the enormous expansion in the literature. Features include: * A new section covering all aspects of ecosystem properties * New chapters on Assembling of Communities Rarification and Extinction Colonisation and Invasion * Principles and methodologies of a range of international tests including case study examples * Chapter summaries for a quick reference guide * Index of species names Written in a very readable style, this book is an invaluable reference source for researchers in the areas of plant, animal, and community ecology, conservation and land management. 'Written by one of the foremost authorities in the field, summarising over 35 years of research. A book all plant ecologists will want to read.' - Jonathan Silvertown, Department of Biological Sciences, The Open University, UK. 'The coverage is outstanding and comprehensive.' - Simon A. Levin, Department of Ecology and Evolutionary Biology, Princeton University, USA
Download or read book Primary Succession and Ecosystem Rehabilitation written by Lawrence R. Walker and published by Cambridge University Press. This book was released on 2003-02-13 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Table of contents
Download or read book Operationalizing the Concepts of Resilience and Resistance for Managing Ecosystems and Species at Risk written by Jeanne C. Chambers and published by Frontiers Media SA. This book was released on 2020-07-17 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large Herbivore Ecology Ecosystem Dynamics and Conservation written by Kjell Danell and published by Cambridge University Press. This book was released on 2006-05-25 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most large herbivores require some type of management within their habitats. Some populations of large herbivores are at the brink of extinction, some are under discussion for reintroduction, whilst others already occur in dense populations causing conflicts with other land use. Large herbivores are the major drivers for forming the shape and function of terrestrial ecosystems. This 2006 book addresses the scientifically based action plans to manage both the large herbivore populations and their habitats worldwide. It covers the processes by which large herbivores not only affect their environment (e.g. grazing) but are affected by it (e.g. nutrient cycling) and the management strategies required. Also discussed are new modeling techniques, which help assess integration processes in a landscape context, as well as assessing the consequences of new developments in the processes of conservation. This book will be essential reading for all involved in the management of both large herbivores and natural resources.
