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Author: Eric Forsman
Publisher: Univ of California Press
ISBN: 0520950593
Category : Science
Languages : en
Pages : 119
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Book Description
The Northern Spotted Owl, a threatened species that occurs in coniferous forests in the western United States, has become a well-known environmental symbol. But how is the owl actually faring? This book contains the results of a long-term effort by a large group of leading researchers to document population trends of the Northern Spotted Owl. The study was conducted on 11 areas in the Pacific Northwest from 1985 to 2008, and its objectives were both to evaluate population trends and to assess relationships between reproductive rates and recruitment of owls and covariates such as weather, habitat, and the invasion of a closely related species, the Barred Owl. Among other findings, the study shows that fecundity was declining in five populations, stable in three, and increasing in three areas. Annual apparent survival rates of adults were declining in 10 out of 11 areas. This broad, synthetic work provides the most complete and up-to-date picture of the population status of this inconspicuous forest owl, which is at the center of the complex and often volatile debate regarding the management of forest lands in the western United States. Researchers: Steven H. Ackers Lawrence S. Andrews David R. Anderson Robert G. Anthony Brian L. Biswell Kenneth P. Burnham Peter C. Carlson Raymond J. Davis Lowell V. Diller Katie M. Dugger Eric D. Forsman Alan B. Franklin Elizabeth M. Glenn Scott A. Gremel Dale R. Herter J. Mark Higley James E. Hines Robert B. Horn Joseph B. Lint James D. Nichols Janice A. Reid James P. Schaberl Carl J. Schwarz Thomas J. Snetsinger Stan G. Sovern Gary C. White
Author: Eric Forsman
Publisher: Univ of California Press
ISBN: 0520950593
Category : Science
Languages : en
Pages : 119
Get Book Here
Book Description
The Northern Spotted Owl, a threatened species that occurs in coniferous forests in the western United States, has become a well-known environmental symbol. But how is the owl actually faring? This book contains the results of a long-term effort by a large group of leading researchers to document population trends of the Northern Spotted Owl. The study was conducted on 11 areas in the Pacific Northwest from 1985 to 2008, and its objectives were both to evaluate population trends and to assess relationships between reproductive rates and recruitment of owls and covariates such as weather, habitat, and the invasion of a closely related species, the Barred Owl. Among other findings, the study shows that fecundity was declining in five populations, stable in three, and increasing in three areas. Annual apparent survival rates of adults were declining in 10 out of 11 areas. This broad, synthetic work provides the most complete and up-to-date picture of the population status of this inconspicuous forest owl, which is at the center of the complex and often volatile debate regarding the management of forest lands in the western United States. Researchers: Steven H. Ackers Lawrence S. Andrews David R. Anderson Robert G. Anthony Brian L. Biswell Kenneth P. Burnham Peter C. Carlson Raymond J. Davis Lowell V. Diller Katie M. Dugger Eric D. Forsman Alan B. Franklin Elizabeth M. Glenn Scott A. Gremel Dale R. Herter J. Mark Higley James E. Hines Robert B. Horn Joseph B. Lint James D. Nichols Janice A. Reid James P. Schaberl Carl J. Schwarz Thomas J. Snetsinger Stan G. Sovern Gary C. White
Author: Robert Gene Anthony
Publisher:
ISBN:
Category : Northern spotted owl
Languages : en
Pages : 52
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Book Description
"We analyzed demographic data from northern spotted owls (Strix occidentalis caurina) from 12 study areas in Washington, Oregon, California for 1985-2003. The purpose of our analyses was to provide an assessment of the status and trends of northern spotted owl populations throughout most of their geographic range"--Page 2.
Author: Eric D. Forsman
Publisher:
ISBN:
Category : Nature
Languages : en
Pages : 132
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Book Description
Author: J. David Wiens
Publisher:
ISBN:
Category : Barred owl
Languages : en
Pages : 0
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Book Description
Evidence indicates that competition with newly established barred owls (Strix varia) is causing rapid declines in populations of northern spotted owls (Strix occidentalis caurina), and that the long-term persistence of spotted owls may be in question without additional management intervention. A pilot study in California showed that lethal removal of barred owls in combination with habitat conservation may be able to slow or even reverse population declines of spotted owls at local scales, but it remains unknown whether similar results can be obtained in larger areas with different forest conditions and where barred owls are more abundant. In 2015, we implemented a before-after-control-impact (BACI) experimental design on two study areas in Oregon and Washington with at least 20 years of pre-treatment demographic data on spotted owls to determine if removal of barred owls can improve population trends of spatially associated spotted owls. Here we provide an overview of our research accomplishments and preliminary results in Oregon and Washington in 2015.
Author: Joseph Lint
Publisher:
ISBN:
Category : Spotted owl
Languages : en
Pages : 52
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Book Description
Author: Joseph Lint
Publisher:
ISBN:
Category : Northern spotted owl
Languages : en
Pages : 188
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Book Description
Author: Elizabeth M. Glenn
Publisher:
ISBN:
Category : Northern spotted owl
Languages : en
Pages : 598
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Book Description
Since the early 1990s, declines in northern spotted owl (Strix occidentalis caurina) populations have been documented through extensive field surveys and range-wide demographic analyses. Although loss of late-successional forest has been credited as the primary cause for spotted owl population declines, environmental variation has also been shown to influence vital rates of many avian species, including spotted owls. Weather and climate are often the most important sources of environmental variation for many species, and population processes can be affected by both large-scale climate fluctuations as well as by local variation in weather. My objectives were to identify associations between weather and climate and demographic rates of northern spotted owls using data collected from marked spotted owls on 6 long-term study areas in Washington and Oregon. I used an information-theoretic approach to rank statistical models representing a priori hypotheses regarding effects of weather and climate on annual survival, reproduction, and realized rate of population change. Annual survival was negatively associated with drier-than-normal conditions on a regional scale at 3 areas, but was also associated with local weather conditions at 3 areas. Number of young fledged per pair per year was negatively associated with cold, wet nesting seasons at 3 areas, although larger-scale weather patterns were associated with reproduction as well. Climate accounted for moderate to high amounts of temporal variation for both survival and reproduction, but little of the spatial variation. My analyses of realized rates of population change indicated continued declines in populations at the 6 study areas, with climate accounting for 3-85% of the temporal variation in lambda. My results suggest that spotted owl populations may face additional challenges if climate in the Pacific Northwest follows the current predictions of year-round warming with warmer, wetter winters and hotter, drier summers in the 21st century.
Author: J. David Wiens
Publisher:
ISBN:
Category : Barred owl
Languages : en
Pages : 17
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Book Description
Author: Joseph Lint
Publisher:
ISBN:
Category : Northern spotted owl
Languages : en
Pages : 176
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Book Description
Author: Richard S. Holthausen
Publisher:
ISBN: 9780756706494
Category :
Languages : en
Pages : 68
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Book Description
Analyzes likely patterns of distribution & persistence of northern spotted owls on the Olympic Peninsula. Focuses on the effects of Federal habitat under provisions of the Northwest Forest Plan; additional benefits to the owl populations of different levels of habitat retention on non-Federal lands; effect of establishing a habitat connection between the Olympic Peninsula & other parts of the owl's range; the likely rate of habitat re-growth in the National Forest & its effect on the owl population; & the likely effect of a worst-case fire. A spatially explicit population model for northern spotted owls was used for the analysis. Reviews current information on demographics & likely owl population numbers on the Olympic Peninsula. Illustrations.
