Joan C Hagar
I am a Research Wildlife Biologist at the U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center. My research focuses on providing information to support management and conservation of native wildlife species and their habitats.
My research interests include forest and wildlife ecology, conservation of biodiversity in managed forests, conservation and management of native Willamette Valley ecosystems, and riparian songbird response to floodplain restoration. Much of my work has focused on the biologically and economically important conifer forests of the PNW that are intensively managed for multiple uses and represent a large area in public domain. My research projects are designed to increase understanding of how conifer forest management affects biodiversity across a range of spatial and temporal scales, and to provide science-based information that can be directly applied in an adaptive management framework.
Professional Experience
2003-Present: Research Wildlife Biologist, USGS, Forest and Rangeland Ecosystem Science Center, Corvallis, OR
1998-2004: Graduate Research Assistant, Department of Forest Science, Oregon State University, Corvallis, OR
1993-1998: Sr. Faculty Research Assistant, Department of Forest Science, Oregon State University, Corvallis, OR
Education and Certifications
Ph.D., Forest Ecology, Oregon State University, Corvallis, OR (2004)
M.S., Forest Ecology, Oregon State University, Corvallis, OR (1993)
B.S., Biological Aspects of Conservation, University of Wisconsin, Madison, WI (1984)
Affiliations and Memberships*
2004-Present: Affiliate Faculty, Oregon State University, Forest Ecosystems and Society
2008-Present: Graduate Faculty, Oregon State University, Master of Natural Resources Program
American Ornithological Society
Association of Field Ornithologists
Oregon Birding Association
Science and Products
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If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Estimating riparian understory vegetation cover with beta regression and copula models
Use of non-alpine anthropogenic habitats by American pikas (Ochotona princeps) in western Oregon, USA
Geostatistical modeling of riparian forest microclimate and its implications for sampling
Thresholds in forest bird occurrence as a function of the amount of early-seral broadleaf forest at landscape scales
Young Stand Thinning and Diversity Study: Response of Songbird Community One Decade Post-Treatment
Assessment and management of dead-wood habitat
Pygmy rabbit surveys on state lands in Oregon
Rainforest birds: A land manager's guide to breeding bird habitat in young conifer forests in the Pacific Northwest
Arthropod prey of Wilson's Warblers in the understory of Douglas-fir forests
Wildlife species associated with non-coniferous vegetation in Pacific Northwest conifer forests: A review
Arthropod prey of Wilson's Warblers in the understory of Douglas-fir forests
Short-term response of songbirds to experimental thinning of young Douglas-fir forests in the Oregon Cascades
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
To request an interview, contact fresc_outreach@usgs.gov or call (541) 750-1030.
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Filter Total Items: 38Estimating riparian understory vegetation cover with beta regression and copula models
Understory vegetation communities are critical components of forest ecosystems. As a result, the importance of modeling understory vegetation characteristics in forested landscapes has become more apparent. Abundance measures such as shrub cover are bounded between 0 and 1, exhibit heteroscedastic error variance, and are often subject to spatial dependence. These distributional features tend to beAuthorsBianca N.I. Eskelson, Lisa Madsen, Joan C. Hagar, Hailemariam TemesgenUse of non-alpine anthropogenic habitats by American pikas (Ochotona princeps) in western Oregon, USA
The American pika (Ochotona princeps Richardson) has long been characterized in field guides and popular literature as an obligate inhabitant of alpine talus and as having relatively low dispersal capability. However, recent work reveals pikas to have broader habitat associations than previously reported. Over a large portion of the western slope of the Cascade Range in Oregon, pikas inhabit relatAuthorsTom Manning, Joan C. HagarGeostatistical modeling of riparian forest microclimate and its implications for sampling
Predictive models of microclimate under various site conditions in forested headwater stream - riparian areas are poorly developed, and sampling designs for characterizing underlying riparian microclimate gradients are sparse. We used riparian microclimate data collected at eight headwater streams in the Oregon Coast Range to compare ordinary kriging (OK), universal kriging (UK), and kriging withAuthorsB.N.I. Eskelson, P. D. Anderson, J.C. Hagar, H. TemesgenThresholds in forest bird occurrence as a function of the amount of early-seral broadleaf forest at landscape scales
Recent declines in broadleaf-dominated, early-seral forest globally as a function of intensive forest management and/or fire suppression have raised concern about the viability of populations dependent on such forest types. However, quantitative information about the strength and direction of species associations with broadleaf cover at landscape scales are rare. Uncovering such habitat relationshAuthorsM.G. Betts, J.C. Hagar, J.W. Rivers, J.D. Alexander, K. McGarigal, B.C. McCombYoung Stand Thinning and Diversity Study: Response of Songbird Community One Decade Post-Treatment
The response of songbird assemblages to commercial thinning is likely to change as vegetation develops over time after thinning. The influence of thinning intensity and pattern on the timing of transitions in bird community composition following thinning is of interest to managers when a goal is to maintain diversity and accelerate the development of late-seral forest structure. We investigated chAuthorsJoan Hagar, Cheryl FriesenAssessment and management of dead-wood habitat
The Bureau of Land Management (BLM) is in the process of revising its resource management plans for six districts in western and southern Oregon as the result of the settlement of a lawsuit brought by the American Forest Resource Council. A range of management alternatives is being considered and evaluated including at least one that will minimize reserves on O&C lands. In order to develop the basAuthorsJoan HagarPygmy rabbit surveys on state lands in Oregon
The pygmy rabbit (Brachylagus idahoensis) is classified by the federal government as a species of concern (i.e., under review by the U.S. Fish and Wildlife Service for consideration as a candidate for listing as threatened or endangered under the Endangered Species Act) because of its specialized habitat requirements and evidence of declining populations. The Oregon Department of Fish and WildlifeAuthorsJoan Hagar, George LienkaemperRainforest birds: A land manager's guide to breeding bird habitat in young conifer forests in the Pacific Northwest
This document (hereafter Guide) has been prepared to assist land managers interested in conducting conservation and management activities to benefit breeding birds associated with young conifer forests in the Pacific Northwest. Audiences targeted for use of the Guide include land trusts, watershed councils, non-commercial private land owners, forest products companies, land-managing conservation oAuthorsBob Altman, Joan HagarArthropod prey of Wilson's Warblers in the understory of Douglas-fir forests
Availability of food resources is an important factor in avian habitat selection. Food resources for terrestrial birds often are closely related to vegetation structure and composition. Identification of plant species important in supporting food resources may facilitate vegetation management to achieve objectives for providing bird habitat. We used fecal analysis to describe the diet of adult WilAuthorsJoan C. Hagar, Kate Dugger, Edward E. StarkeyWildlife species associated with non-coniferous vegetation in Pacific Northwest conifer forests: A review
Non-coniferous vegetation, including herbs, shrubs, and broad-leaved trees, makes a vital contribution to ecosystem function and diversity in Pacific Northwest conifer forests. However, forest management has largely been indifferent or detrimental to shrubs and trees that have low commercial value, in spite of a paradigm shift towards more holistic management in recent decades. Forest management pAuthorsJ.C. HagarArthropod prey of Wilson's Warblers in the understory of Douglas-fir forests
Availability of food resources is an important factor in avian habitat selection. Food resources for terrestrial birds often are closely related to vegetation structure and composition. Identification of plant species important in supporting food resources may facilitate vegetation management to achieve objectives for providing bird habitat. We used fecal analysis to describe the diet of adult WilAuthorsJ.C. Hagar, K.M. Dugger, E. E. StarkeyShort-term response of songbirds to experimental thinning of young Douglas-fir forests in the Oregon Cascades
Commercial thinning has the potential to increase structural diversity in managed conifer stands and redirect development of young stands towards structure characteristic of late-seral habitats. Thinning to increase diversity, however, is likely to require different strategies than thinning to maximize timber production. To prescribe thinning regimes that will promote diversity, managers need moreNon-USGS Publications**
Hagar, J.C., Howlin, S., Ganio, L., 2004, Short-term response of songbirds to experimental thinning of young Douglas-fir forests in the Oregon Cascades: Forest Ecology and Management, v. 199, p. 333-347.Hagar, J.C., Stern, M.A., 2001, Avifauna in oak woodlands of the Willamette Valley, Oregon: Northwestern Naturalist, v. 82, p. 12-15.Hagar, J.C., McComb, W.C., Emmingham, W.H., 1996, Bird communities in commercially thinned and unthinned Douglas-fir stands of western Oregon: Wildlife Society Bulletin, v. 24, no. 2, p. 353-366.Dellasala, D.A., Hagar, J.C., Engel, K.A., McComb, W.C., Fairbanks, R.L., Campbell, E.G., 1996, Effects of silvicultultural modifications of temperate rainforest on breeding and wintering bird communities, Prince of Wales Island, southeast Alaska: The Condor, v. 98, p. 706-721.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government