Download or read book Competitive Interactions and Resource Partitioning Between Northern Spotted Owls and Barred Owls in Western Oregon written by J. David Wiens and published by . This book was released on 2012 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: The federally threatened northern spotted owl (Strix occidentalis caurina) is the focus of intensive conservation efforts that have led to much forested land being reserved as habitat for the owl and associated wildlife species throughout the Pacific Northwest of the United States. Recently, however, a relatively new threat to spotted owls has emerged in the form of an invasive competitor: the congeneric barred owl (Strix varia). As barred owls have rapidly expanded their populations into the entire range of the northern spotted owl, mounting evidence indicates that they are displacing, hybridizing with, and even killing spotted owls. The barred owl invasion into western North America has made an already complex conservation issue even more contentious, and a lack of information on the ecological relationships between the 2 species has hampered conservation efforts. During 2007-2009 I investigated spatial relationships, habitat selection, diets, survival, and reproduction of sympatric spotted owls and barred owls in western Oregon, USA. My overall objective was to determine the potential for and possible consequences of competition for space, habitat, and food between the 2 species. My study included 29 spotted owls and 28 barred owls that were radio-marked in 36 neighboring territories and monitored over a 24-month tracking period. Based on repeated surveys of both species, the number of territories occupied by pairs of barred owls in the 745 km2 study area (82) greatly outnumbered those occupied by pairs of spotted owls (15). Estimates of mean size of home-ranges and core-use areas of spotted owls (1,843 ha and 305 ha, respectively) were 2-4 times larger than those of barred owls (581 ha and 188 ha, respectively). Individual spotted and barred owls in adjacent territories often had overlapping home ranges, but inter-specific space sharing was largely restricted to broader foraging areas in the home range with minimal spatial overlap among core-use areas. I used an information-theoretic approach to rank discrete choice models representing alternative hypotheses about the influence of forest conditions and interspecific interactions on species-specific patterns of nighttime habitat selection. Spotted owls spent a disproportionate amount of time foraging on steep slopes in ravines dominated by old (>120 yrs old) conifer trees. Barred owls used available forest types more evenly than spotted owls, and were most strongly associated with patches of large hardwood and conifer trees that occupied relatively flat areas along streams. Spotted and barred owls differed in the relative use of old conifer forest (higher for spotted owls) and slope conditions (steeper slopes for spotted owls). I found no evidence that the 2 species differed in their use of young, mature, and riparian-hardwood forest types, and both species avoided forest-nonforest edges. The best resource selection function for spotted owls indicated that the relative probability of a location being selected was reduced if the location was within or in close proximity to a core-use area of a barred owl. I used pellet analysis and measures of food niche overlap to examine the potential for dietary competition between spatially associated pairs of spotted owls and barred owls. I identified 1,223 prey items from 15 territories occupied by pairs of spotted owls and 4,299 prey items from 24 territories occupied by pairs of barred owls. Diets of both species were dominated by nocturnal mammals, but diets of barred owls included many terrestrial, aquatic, and diurnal prey species that were rare or absent in diets of spotted owls. Northern flying squirrels (Glaucomys sabrinus), woodrats (Neotoma fuscipes, N. cinerea), and lagomorphs (Lepus americanus, Sylvilagus bachmani) were particularly important prey for both owl species, accounting for 81% and 49% of total dietary biomass for spotted owls and barred owls, respectively. Dietary overlap between pairs of spotted and barred owls in adjacent territories ranged from 28-70% (mean = 42%) In addition to overlap in resource use, I also identified strong associations between the presence of barred owls and the behavior of spotted owls, as shown by changes in space-use, habitat selection, and reproductive output of spotted owls exposed to different levels of spatial overlap with barred owls in adjacent territories. Barred owls in my study area displayed both numeric and demographic superiority over spotted owls; the annual survival probability of radio-marked spotted owls from known-fate analyses (0.81, SE = 0.05) was lower than that of barred owls (0.92, SE = 0.04), and barred owls produced over 6 times as many young over a 3-year period as spotted owls. Survival of both species was positively associated with an increasing proportion of old (>120 yrs old) conifer forest within the home range, which suggested that availability of old forest was a potential limiting factor in the competitive relationship between the 2 species. When viewed collectively, my results support the hypothesis that interference competition with a high density of barred owls for territorial space can act to constrain the availability of critical resources required for successful recruitment and reproduction of spotted owls. My findings have broad implications for the conservation of spotted owls, as they suggest that spatial heterogeneity in survival and reproduction may arise not only because of differences among territories in the quality of forest habitat, but also because of the spatial distribution of an invasive competitor.
Download or read book Competitive Interactions and Resource Partitioning Between Northern Spotted Owls and Barred Owls in Western Oregon written by J. David Wiens and published by . This book was released on 2012 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: The federally threatened northern spotted owl (Strix occidentalis caurina) is the focus of intensive conservation efforts that have led to much forested land being reserved as habitat for the owl and associated wildlife species throughout the Pacific Northwest of the United States. Recently, however, a relatively new threat to spotted owls has emerged in the form of an invasive competitor: the congeneric barred owl (Strix varia). As barred owls have rapidly expanded their populations into the entire range of the northern spotted owl, mounting evidence indicates that they are displacing, hybridizing with, and even killing spotted owls. The barred owl invasion into western North America has made an already complex conservation issue even more contentious, and a lack of information on the ecological relationships between the 2 species has hampered conservation efforts. During 2007-2009 I investigated spatial relationships, habitat selection, diets, survival, and reproduction of sympatric spotted owls and barred owls in western Oregon, USA. My overall objective was to determine the potential for and possible consequences of competition for space, habitat, and food between the 2 species. My study included 29 spotted owls and 28 barred owls that were radio-marked in 36 neighboring territories and monitored over a 24-month tracking period. Based on repeated surveys of both species, the number of territories occupied by pairs of barred owls in the 745 km2 study area (82) greatly outnumbered those occupied by pairs of spotted owls (15). Estimates of mean size of home-ranges and core-use areas of spotted owls (1,843 ha and 305 ha, respectively) were 2-4 times larger than those of barred owls (581 ha and 188 ha, respectively). Individual spotted and barred owls in adjacent territories often had overlapping home ranges, but inter-specific space sharing was largely restricted to broader foraging areas in the home range with minimal spatial overlap among core-use areas. I used an information-theoretic approach to rank discrete choice models representing alternative hypotheses about the influence of forest conditions and interspecific interactions on species-specific patterns of nighttime habitat selection. Spotted owls spent a disproportionate amount of time foraging on steep slopes in ravines dominated by old (>120 yrs old) conifer trees. Barred owls used available forest types more evenly than spotted owls, and were most strongly associated with patches of large hardwood and conifer trees that occupied relatively flat areas along streams. Spotted and barred owls differed in the relative use of old conifer forest (higher for spotted owls) and slope conditions (steeper slopes for spotted owls). I found no evidence that the 2 species differed in their use of young, mature, and riparian-hardwood forest types, and both species avoided forest-nonforest edges. The best resource selection function for spotted owls indicated that the relative probability of a location being selected was reduced if the location was within or in close proximity to a core-use area of a barred owl. I used pellet analysis and measures of food niche overlap to examine the potential for dietary competition between spatially associated pairs of spotted owls and barred owls. I identified 1,223 prey items from 15 territories occupied by pairs of spotted owls and 4,299 prey items from 24 territories occupied by pairs of barred owls. Diets of both species were dominated by nocturnal mammals, but diets of barred owls included many terrestrial, aquatic, and diurnal prey species that were rare or absent in diets of spotted owls. Northern flying squirrels (Glaucomys sabrinus), woodrats (Neotoma fuscipes, N. cinerea), and lagomorphs (Lepus americanus, Sylvilagus bachmani) were particularly important prey for both owl species, accounting for 81% and 49% of total dietary biomass for spotted owls and barred owls, respectively. Dietary overlap between pairs of spotted and barred owls in adjacent territories ranged from 28-70% (mean = 42%) In addition to overlap in resource use, I also identified strong associations between the presence of barred owls and the behavior of spotted owls, as shown by changes in space-use, habitat selection, and reproductive output of spotted owls exposed to different levels of spatial overlap with barred owls in adjacent territories. Barred owls in my study area displayed both numeric and demographic superiority over spotted owls; the annual survival probability of radio-marked spotted owls from known-fate analyses (0.81, SE = 0.05) was lower than that of barred owls (0.92, SE = 0.04), and barred owls produced over 6 times as many young over a 3-year period as spotted owls. Survival of both species was positively associated with an increasing proportion of old (>120 yrs old) conifer forest within the home range, which suggested that availability of old forest was a potential limiting factor in the competitive relationship between the 2 species. When viewed collectively, my results support the hypothesis that interference competition with a high density of barred owls for territorial space can act to constrain the availability of critical resources required for successful recruitment and reproduction of spotted owls. My findings have broad implications for the conservation of spotted owls, as they suggest that spatial heterogeneity in survival and reproduction may arise not only because of differences among territories in the quality of forest habitat, but also because of the spatial distribution of an invasive competitor.
Download or read book Experimental Removal of Barred Owls to Benefit Threatened Northern Spotted Owls written by and published by . This book was released on 2012 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Competitive Interactions Between Spotted and Barred Owls in Western Oregon written by Dr. Robert Anthony and published by . This book was released on 2007 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wildlife Habitat Conservation written by Michael L. Morrison and published by JHU Press. This book was released on 2015-05-15 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: A book that emphasized the concept of wildlife habitat for a generation of students and professionals is now available to even more readers. "Habitat" is probably the most common term in ecological research. Elementary school students are introduced to the term, college students study the concept in depth, hunters make their plans based on it, nature explorers chat about the different types, and land managers spend enormous time and money modifying and restoring habitats. Although a broad swath of people now have some notion of what habitat is, the scientific community has by and large failed to define it concretely, despite repeated attempts in the literature to come to meaningful conclusions regarding what habitat is and how we should study, manipulate, and ultimately conserve it. Wildlife Habitat Conservation presents an authoritative review of the habitat concept, provides a scientifically rigorous definition, and emphasizes how we must focus on those critical factors contained within what we call habitat. The result is a habitat concept that promises long-term persistence of animal populations. Key concepts and items in the book include: • Rigorous and standard conceptual definitions of wildlife and their habitat. • A discussion of the essential integration of population demographics and population persistence with the concept of habitat. • The importance of carryover and lag effects, behavioral processes, genetics, and species interactions to our understanding of habitat. • An examination of spatiotemporal heterogeneity, realized through fragmentation, disruption to eco-evolutionary processes, and alterations to plant and animal assemblages. • An explanation of how anthropogenic effects alter population size and distribution (isolation), genetic processes, and species diversity (including exotic plants and animals). • Advocacy of proactive management and conservation through predictive modeling, restoration, and monitoring. Each chapter is accessibly written in a style that will be welcomed by private landowners and public resource managers at local, state, and federal levels. Also ideal for undergraduate and graduate natural resource and conservation courses, the book is organized perfectly for a one-semester class. Published in association with The Wildlife Society.
Download or read book Wildlife Management and Conservation written by Paul R. Krausman and published by JHU Press. This book was released on 2022-09-20 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: The definitive textbook for students of wildlife management, now updated to cover the latest techniques, tools, and topics. Wildlife Management and Conservation presents a clear overview of the management and conservation of animals, their habitats, and how people influence both. The relationship among these three components of wildlife management is explained in chapters written by leading experts and is designed to prepare students for careers in which they will be charged with maintaining healthy animal populations. To be successful wildlife professionals, they will need to find ways to restore depleted populations, reduce overabundant, introduced, or pest species, and manage relationships among various human stakeholders. This book gives them the basic knowledge necessary to accomplish these goals. This second edition, which is updated throughout, features several new and expanded topics, including communication in the wildlife profession, fire science, Indigenous models of management and conservation, plant–animal interactions, quantitative analysis of wildlife populations, and a detailed glossary. The book also covers: • Human dimensions of wildlife management • Animal behavior • Predator–prey relationships • Structured decision making • Issues of scale in wildlife management • Wildlife health • Historical context of wildlife management and conservation • Hunting and trapping • Nongame species • Nutrition ecology • Water management • Climate change • Conservation planning The most widely used foundational text in the field, this is the perfect resource not only for students but also for early career professionals and those in related fields who need to understand the core tenets and tools of wildlife conservation and management. Contributors: C. Jane Anderson, Bart M. Ballard, Warren B. Ballard, John A. Bissonette, Clint Boal, Scott B. Boyle, Leonard A. Brennan, Robert D. Brown, James W. Cain III, Tyler A. Campbell, Michael J. Cherry, Michael R. Conover, Daniel J. Decker, Randall W. DeYoung, Jonathan B. Dinkins, W. Sue Fairbanks, Selma N. Glasscock, James B. Grand, Michael J. Haney, James R. Heffelfinger, Scott E. Henke, Fidel Hernandez, Davie G. Hewitt, C. L. Hoving, David A. Jessup, Heather E. Johnson, Winifred B. Kessler, John L. Koprowski, Paul R. Krausman, William P. Kuvlesky, Jr., Roel R. Lopez, R. W. Mannan, Melissa J. Merrick, L. Scott Mills, Michael S. Mitchell, Michael L. Morrison, Anna M. Muñoz, John F. Organ, Katherine L. Parker, William F. Porter, Shawn J. Riley, Steven S. Rosenstock, Michael C. Runge, Susan P. Rupp, William F. Siemer, Robert J. Steidl, Kelley M. Stewart
Download or read book Biodiversity and Conservation in Forests written by Diana F. Tomback and published by MDPI. This book was released on 2019-01-18 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Biodiversity and Conservation in Forests" that was published in Forests
Download or read book Ecological Challenges and Conservation Conundrums written by John A. Wiens and published by John Wiley & Sons. This book was released on 2016-02-22 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Short, compelling, but mostly thought-provoking essys that encompass many of the central issues shaping ecology and conservation in the changing world Collected essays from one of the best known ecologists and conservationists in the world Includes all issues at the cutting edge of the interface between ecology and conservation Attractive to a broad audience of ecologists, conservationists, natural resource managers, policy makers, and naturalists
Download or read book Influence of Habitat Abundance and Fragmentation on Northern Spotted Owls in Western Oregon written by Joseph S. Meyer and published by . This book was released on 1998 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Current management for the northern spotted owl (Strix occidentalis caurina) is largely driven by metapopulation models or individually-based models that assume the success of juvenile dispersal in a fragmented landscape is a primary factor determining the future existence of spotted owls in the Pacific Northwest. We tested hypotheses about fragmentation by comparing sites known to be occupied by spotted owls with random sites to determine if relationships existed between landscape indices and spotted owl presence and productivity in western Oregon"--Page 5
Download or read book Conservation Science and Advocacy for a Planet in Peril written by Dominick A. DellaSala and published by Elsevier. This book was released on 2021-08-18 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conservation Science and Advocacy for a Planet in Peril: Speaking Truth to Power helps equip scientists working on environmental and sustainability challenges with new tactics for success. Global efforts and cooperation by member states of environmental conventions have steadily increased but lack efficient and scalable mechanisms of translating conservation science to policy. The gap between science and policy is growing and very little time remains before the climate change and biodiversity lossess trigger widespread disruptions of the planet's life support systems. This book covers these important topics, providing a must read for environmental and conservation scientists, climate change activists, students, social scientists, economic professionals, sustainable businesses and policymakers. - Provides an unprecedented collection of local, regional, and national case studies from scientists and practitioners engaged in outreach to decision makers and the public - Covers personal accounts that bring science into policymaking, providing usable guidelines for those working to bridge this gap - Includes the requisite information needed for effective communications and campaign strategies by sharing lessons learned
Download or read book Ornithology written by Michael L. Morrison and published by Johns Hopkins University Press. This book was released on 2018-09-03 with total page 1017 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wood, Robert M. Zink, Benjamin Zuckerberg
Download or read book Owls of North America and the Caribbean written by Scott Weidensaul and published by Houghton Mifflin Harcourt. This book was released on 2015 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: "With detailed information about identification, calls, habitat, breeding, nesting, and behavior, this reference guide has the most up-to-date information about natural history, taxonomy, biology, ecology, migration and conservation status."--Book jacket.
Download or read book Advances in Renewable Energy and Sustainable Development written by Zhoufu Liang and published by CRC Press. This book was released on 2022-12-07 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Renewable Energy and Sustainable Development focuses on cutting-edge research areas including renewable energy and sustainable development. As a leader in the global megatrend of science and technology innovation, China has been creating an increasingly open environment for science and technology innovation, increasing the depth and breadth of academic cooperation, and building an innovation community that benefits all people. These efforts make a new contribution to globalization and the building of a community for a shared future. The proceedings feature the most cutting-edge research directions and achievements related to Renewable Energy and Sustainable Development. Subjects in the proceedings include: Hydraulic Engineering Environmental Science and Environmental Engineering Energy Engineering and Energy Technologies Green Manufacturing Energy Policy and Economics Energy Security and Clean Use Geothermal Energy
Download or read book How Birds Evolve written by Douglas J. Futuyma and published by Princeton University Press. This book was released on 2024-10-29 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Why are male birds often so brightly colored? Why do some birds lay more eggs than others? Will bird species adapt to climate change? In How Birds Evolve, Douglas Futuyma invites readers into the amazing world of bird evolution to answer these and other questions. Futuyma's goal in this book is not to offer a comprehensive evolutionary history of birds, but to explore how the processes of evolution produced the distinctive features and behaviors we observe in birds today as well as their impressive diversity. Using one or two birds per chapters as a lens into broader questions, Futuyma explores how a bird's evolutionary history helps us understand the diversity of species and the bird tree of life and how natural selection explains most of the characteristics of birds from how populations adapt to sexual selection and birds' amazing social behavior. Futuyma concludes by discussing the future of birds, particularly patterns of extinction and whether they can adapt to a changing climate. Ultimately, Futuyman wants readers to see that evolutionary biology helps us to better understand birds, and that the reverse is also true: studies of birds have informed almost every aspect of evolutionary biology, from Darwin to today"--
Download or read book Habitat Utilization by Spotted Owls in the West Central Cascades of Oregon written by Eric D. Forsman and published by . This book was released on 1980 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eight adult spotted owls (Strix occidentalis) on the west slope of the Cascade Range in Oregon were fitted with radio transmitters and observed for periods ranging from 271 to 383 days. Mean home range size for the owls was 1,177 ha (range = 920-1,376 ha). There was no significant difference between home range size of males and females. On the average, home ranges of individuals occupying adjacent territories overlapped by 12 percent (range = 3-25 percent). Home ranges of paired individuals overlapped by 50 to 73 percent. The size and shape of home ranges varied on a seasonal basis; generally, the largest home ranges were observed during winter. Nest sites were centrally located within the home ranges utilized by the owls. On the radiotelemetry study area, the mean nearest neighbor distance between nests of adjacent pairs was 2.88 km. On 11 other areas in western Oregon where suitable habitat was available, mean nearest neighbor distances ranged from 1.68 to 3.04 km. The overall mean nearest neighbor distance for the 12 areas was 2.42 km. Home ranges occupied by the radio tagged owls were so large that consistent defense of the entire home range was impossible. Territorial defense appeared to take the form of a decreasing zone of influence centered around the nest; areas near each nest were defended consistently, but defense became increasingly inconsistent with distance from the nest. Discrete territorial boundaries could not be determined and probably did not exist. Territorial interactions between individuals of the same sex were much more aggressive than interactions between individuals of opposite sex. Spotted owls may have responded less aggressively toward individuals of the opposite sex because the advantage of allowing potential mate replacements to remain within the territory outweighed other considerations. Except for a few instances in which 2 of the owls foraged in recently clear-cut areas or in rock talus, virtually all foraging occurred in forests over 30 years old. Old-growth forests, which covered 36 to 64 percent of the area on individual owl home ranges, were strongly preferred for foraging by all of the owls; 92 percent of all foraging occurred in such forests. Utilization of younger forests (30 to 200 years old) was generally either less than or not significantly different than expected, indicating that younger forests were less desirable for foraging than old-growth stands. Old-growth forests were also preferred for roosting (97 percent of all roosts). Large old trees apparently were preferred for roosting during inclement weather because they provided better overhead protection from rain and snow. Small trees in the understory were preferred during warm weather because they provided greater protection from high temperatures and solar radiation. Spotted owls were primarily nocturnal. On the average, they left their day roasts to begin foraging at 14 minutes after sunset and stopped foraging at 21 minutes before sunrise. Diurnal foraging was limited primarily to opportunistic attempts to capture animals that wandered into roost areas. The usual method of foraging was to move from perch to perch at night, watching and listening for potential prey. The average rate of movement while foraging in this manner was 247 m/hr, and the average distance moved per nightly foraging period was 2,782 meters (range = 320-8,895 m). Seven species of mammals comprised the nucleus of the diet, the northern flying squirrel (Glaucomys sabrinus), red tree vole (Phenacomys longicaudus), western red-backed vole (Clethrionomys occidentalis), deer mouse (Peromyscus maniculatus), western pocket gopher (Thomomys mazama), snowshoe hare (Lepus americanus), and bushy-tailed woodrat (Neotoma cinerea). The flying squirrel, the most common animal in the diet, comprised 42 percent of all prey captured. During mid-winter, 85 percent of the prey captured were arboreal mammals. During the rest of the year, terrestrial prey became more abundant in the diet, but the flying squirrel remained the most common animal in the diet. Mean prey size and dietary composition for male and female spotted owls were not significantly different; this suggested that males and females did not partition the prey resource on the basis of size or species. Estimates of biomass consumed per owl per day on the study area ranged from 77.6 to 164.8 g, but the latter estimate was probably inflated. Four hypotheses are presented to explain why spotted owls foraged primarily in older forests and avoided recently cutover areas: (1) the biomass of prey preferred by the owls may have been greater in older forests than in cutover areas, (2) switching from arboreal mammals in older forests to terrestrial mammals in cutover areas might have resulted in increased competition with other nocturnal predators, (3) prey may have been less accessible in the dense vegetation that developed on cutover areas, and (4) spotted owls may have been more susceptible to predation in cutover areas where escape cover was absent.
Download or read book Final Environmental Impact Statement on Management for the Northern Spotted Owl in the National Forests written by and published by . This book was released on 1992 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Development of Management Plans for Spotted Owls in Western Oregon by the Forest Service and Bureau of Land Management written by Sharon Elaine Churchill and published by . This book was released on 1989 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
