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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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A person holding a small yellow bird with dark feathers on wings, forest in the background

Birds as Indicators of Ecosystem Health

Birds are excellent indicators of ecosystem condition because they are responsive to environmental change, have important ecological functions – such as seed dispersal and insect consumption, and are easy to observe.
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Species Management Research Program, Forest and Rangeland Ecosystem Science Center
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Birds as Indicators of Ecosystem Health

Birds are excellent indicators of ecosystem condition because they are responsive to environmental change, have important ecological functions – such as seed dispersal and insect consumption, and are easy to observe.
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USGS science for a changing world

Habitat Mapping and Modeling

Accurately quantifying and mapping wildlife habitat is critical to investigations of species distribution and habitat relationships, and can greatly facilitate management of forests for multiple resources. However acquiring field-based, empirical data is often costly and labor intensive. Modeling provides an alternative technique for describing and mapping habitat, but the usefulness of models...
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Ecosystems Mission Area, Species Management Research Program, Forest and Rangeland Ecosystem Science Center
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Habitat Mapping and Modeling

Accurately quantifying and mapping wildlife habitat is critical to investigations of species distribution and habitat relationships, and can greatly facilitate management of forests for multiple resources. However acquiring field-based, empirical data is often costly and labor intensive. Modeling provides an alternative technique for describing and mapping habitat, but the usefulness of models...
Learn More
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USGS science for a changing world

Effects of Management on Wildlife and Habitats

Conifer forests in the Pacific Northwest are biologically and economically important, are intensively managed for multiple uses, and represent a large area in public domain. Therefore, understanding how management of conifer forests affects biodiversity across a range of spatial and temporal scales is critical for land management agencies.
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Land Management Research Program, Forest and Rangeland Ecosystem Science Center
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Effects of Management on Wildlife and Habitats

Conifer forests in the Pacific Northwest are biologically and economically important, are intensively managed for multiple uses, and represent a large area in public domain. Therefore, understanding how management of conifer forests affects biodiversity across a range of spatial and temporal scales is critical for land management agencies.
Learn More
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USGS science for a changing world

Ecology of Rare and Declining Species and Communities of Conservation Concern

Special status species and habitats are often sentinels of accelerated ecosystem change and, by definition, are priorities for protection, restoration, or focused management.
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Ecosystems Mission Area, Species Management Research Program, Forest and Rangeland Ecosystem Science Center
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Ecology of Rare and Declining Species and Communities of Conservation Concern

Special status species and habitats are often sentinels of accelerated ecosystem change and, by definition, are priorities for protection, restoration, or focused management.
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Small bird in a bush

Disentangling the Effects of Climate and Landscape Change on Bird Population Trends in the Western U.S. and Canada

Climate change has been implicated in the range shifts and population declines of many species, but the confounding of climate change with other variables, particularly landscape change, hampers inference about causation. Climate envelope models have been used to predict population trends and future distributions, but the reliability of such predictions remains relatively unknown; without tests of
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Climate Adaptation Science Centers
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Disentangling the Effects of Climate and Landscape Change on Bird Population Trends in the Western U.S. and Canada

Climate change has been implicated in the range shifts and population declines of many species, but the confounding of climate change with other variables, particularly landscape change, hampers inference about causation. Climate envelope models have been used to predict population trends and future distributions, but the reliability of such predictions remains relatively unknown; without tests of
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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.

Forest stands and LiDAR derived model estimates of marbled murrelet (Brachyramphus marmoratus) occupancy in the Coos Bay BLM District, Southwestern Oregon

We used murrelet occupancy data collected by the Bureau of Land Management Coos Bay District and canopy metrics calculated from discrete return airborne LiDAR data to fit a logistic regression model predicting the probability of occupancy. Our final model for stand-level occupancy included distance to coast and 5 LiDAR-derived variables describing canopy structure. This dataset is a shapefile of f
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Forest and Rangeland Ecosystem Science Center

Bird Responses to Young Stand Thinning in Western Oregon in 2013

The US Forest Service, Pacific Northwest Research Station, and Oregon State University established the Young Stand Thinning and Diversity Study (YSTDS) in 1990 to demonstrate and test options for young stand management in western Oregon. The YSTDS is designed to determine if different thinning, underplanting, and snag creation treatments in 35-50 year-old plantations can accelerate the development
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Forest and Rangeland Ecosystem Science Center

Mesocarnivore Survey of Crater Lake National Park, Klamath Network, 2016

Remote camera stations were set up in Crater Lake National Park from June to October 2016 to document occurrence of mesocarnivores and other wildlife. 124 cameras were set up at 31 primary sampling units (clusters of 4 cameras) throughout the park. Random locations for primary sampling units were chosen using a 3-km sampling grid over the park area. The dataset contains all species observed within
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Forest and Rangeland Ecosystem Science Center

Mesocarnivore Survey of Lava Beds National Monument, Klamath Network, 2018 (ver. 2.0, April 2022)

Remote camera stations were set up in Lava Beds National Monument and Modoc National Forest from January to May 2018 to document occurrence of mesocarnivores and other wildlife. Thirty-three cameras were set up at 12 primary sampling units (clusters of one to four cameras) throughout the park. Potentially suitable habitat occurred in small patches in Lava Beds National Monument with cameras were p
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Forest and Rangeland Ecosystem Science Center

Mesocarnivore Survey of Lassen Volcanic National Park, Klamath Network, 2017-2018 (ver. 2.0, April 2022)

Remote camera stations were set up in Lassen Volcanic National Park from August to October 2017 and June to September 2018 to document occurrence of mesocarnivores and other wildlife. 126 cameras were set up at 32 primary sampling units (clusters of two to four cameras) throughout the park. Random locations for primary sampling units were chosen using a 3-km sampling grid over the park area. The d
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Forest and Rangeland Ecosystem Science Center

Mesocarnivore Survey of Whiskeytown National Recreation Area, Klamath Network, 2018-2019

Remote camera stations were set up in Whiskeytown National Recreation Area from October 2018 to January 2019 to document occurrence of mesocarnivores and other wildlife. Forty-five single-camera sampling stations were setup throughout the park. Camera locations were chosen based on the Klamath Monitoring Network vegetation plots. The dataset contains all species observed within the study time-fram
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Forest and Rangeland Ecosystem Science Center

Mesocarnivore Survey of Oregon Caves National Monument and Preserve, Klamath Network, 2017 (ver. 2.1, July 2022)

Remote camera stations were set up in Oregon Caves National Monument and Preserve from February through April 2017 to document occurrence of mesocarnivores and other wildlife. Fifteen cameras were set up at four primary sampling units (clusters of three to four cameras) throughout the park. Random locations for primary sampling units were chosen using a 3-km sampling grid over the park area. The d
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Forest and Rangeland Ecosystem Science Center

Forest management and cervid herbivory data from Western Oregon, USA, 2012

Land management practices often directly alter vegetation structure and composition, but the degree to which ecological processes such as herbivory interact with management to influence biodiversity is less well understood. We hypothesized that intensive forest management and large herbivores have compounding effects on early-seral plant communities and plantation establishment (i.e., tree surviva
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Forest and Rangeland Ecosystem Science Center

Estimated Probabilities from Lidar Models for Marbled Murrelet (Brachyramphus marmoratus) Occupancy in Forest Vegetation Stands in the Siuslaw National Forest, Oregon

We developed a LiDAR-based habitat model for the threatened Marbled Murrelet (MAMU) in the Siuslaw National Forest, Oregon, using a two-step approach. First, we tested the applicability of the LiDAR-based model developed for the Coos Bay District of the Bureau of Land Management (BLM) to the Siuslaw N.F. In the second step, we tested alternative habitat models developed with forest structural data
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Forest and Rangeland Ecosystem Science Center

Created snag characteristics and cavity-nesting bird associations in the CFIRP stands, McDonald-Dunn Research Forest, Corvallis, OR, USA, 2016

Snags provide critical habitat for nearly one-third of wildlife species in forests of the Pacific Northwest, so historic declines in snags are thought to have had a strong impact on biodiversity. Resource managers often create snags to mitigate the scarcity of snags within managed forests, but information regarding the function and structure of created snags across long time periods (20 years) is
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Forest and Rangeland Ecosystem Science Center

Avian abundance and oak mistletoe survey data from the Willamette Valley, Oregon, 2013-2015

This dataset includes two spreadsheets: The "Avian_abundance_oak_mistletoe_bird_data" spreadsheet contains data regarding Oregon White Oak tree (Quercus garryana) measurements such as height, diameter and crown volume along with microhabitat data including number of mistletoe infections, number of cavities, amount of dead wood, amount of loose/missing bark, amount of poison oak, amount of bole cra
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Forest and Rangeland Ecosystem Science Center

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.

USGS
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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.

Filter Total Items: 37

Level and pattern of overstory retention shape the abundance and long-term dynamics of natural and created snags

Standing dead trees, or snags, serve myriad functions in natural forests, but are often scarce in forests managed for timber production. Variable retention (VR), the retention of live and dead trees through harvest, has been adopted globally as a less intensive form of regeneration harvest. In this study, we explore how two key elements of VR systems — level (amount) and spatial pattern of live-tr
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Charles B. Halpern, Allison K. Rossman, Joan Hagar
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Ecosystems Mission Area, Species Management Research Program, Forest and Rangeland Ecosystem Science Center

Monitoring framework to evaluate effectiveness of aquatic and floodplain habitat restoration activities for native fish along the Willamette River, northwestern Oregon

Since 2008, large-scale restoration programs have been implemented along the Willamette River, Oregon, to address historical losses of floodplain habitats caused by dam construction, bank protection, large wood removal, land conversion, and other anthropogenic influences. The Willamette Focused Investment Partnership (WFIP) restoration initiative brings together more than 16 organizations to impro
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Mackenzie K. Keith, J. Rose Wallick, Rebecca L Flitcroft, Tobias J. Kock, Laura A. Brown, Rich Miller, Joan C. Hagar, Kathleen Guillozet, Krista L. Jones
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Ecosystems Mission Area, Water Resources Mission Area, Forest and Rangeland Ecosystem Science Center, Oregon Water Science Center

Evaluating the role of active management in mature Douglas-fir (Pseudotsuga menziesii) stands for songbird conservation

Forest birds, particularly those associated with late-successional forests, are of widespread conservation interest. Although birds are among the more widely studied taxa of forest wildlife, relatively few studies have examined the long-term effects of active management (i.e., intentional stand density reduction) on the forest bird assemblage. This is an important omission, as changes in stand str
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Neil Williams, Joan Hagar, Matthew Powers
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Ecosystems Mission Area, Forest and Rangeland Ecosystem Science Center

Diet composition of Fishers (Pekania pennanti) reintroduced on the Olympic Peninsula, Washington

Knowledge of diet composition can inform management strategies and efforts to recover endangered carnivore populations in vacant portions of their historic ranges. One such species, the Fisher (Pekania pennanti), was extirpated in Washington State prior to any formal documentation of its food habits in the coastal coniferous forests of western Washington. Fisher recovery efforts in Washington, bas
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Patricia J. Happe, Shelby H. Pace, Laura R. Prugh, Kurt Jenkins, Jeffrey C. Lewis, Joan Hagar
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Ecosystems Mission Area, Forest and Rangeland Ecosystem Science Center

Western purple martin (Progne subis arboricola) occurrence on the Siuslaw National Forest, Summer 2019

The western subspecies of the purple martin (Progne subis arboricola) is currently listed as a “critically” sensitive species in four ecoregions of western Oregon: Coast Range, Klamath Mountains, West Cascades, and Willamette Valley (Oregon Department of Fish and Wildlife, 2019). Importantly distinct from the abundant and widespread eastern subspecies (Progne subis subis), the western subspecies i
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Joan Hagar, Eric Branch
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Ecosystems Mission Area, Forest and Rangeland Ecosystem Science Center

The snag’s the limit: Habitat selection modeling for the western purple martin in a managed forest landscape

The western purple martin (Progne subis arboricola), an avian insectivore, is a species of conservation concern throughout the Pacific Northwest. Compared to the well-studied eastern subspecies (Progne subis subis), little is known of the life history and biology of the western subspecies. Availability of breeding habitat is believed to be a major limiting factor for western purple martins in fore
Authors
Lorelle M. Sherman, Joan Hagar
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Ecosystems Mission Area, Forest and Rangeland Ecosystem Science Center

Removal of cattle grazing correlates with increases in vegetation productivity and in abundance of imperiled breeding birds

Livestock grazing is the most prevalent land use practice in the western United States and a widespread cause of degradation of riparian vegetation. Riparian areas provide high-quality habitat for many species of declining migratory breeding birds. We analyzed changes in vegetation and bird abundance at a wildlife refuge in southeastern Oregon over 24 years, following cessation of 120 years of liv
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Sharon Poessel, Joan Hagar, Patricia Haggerty, Todd E. Katzner
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Ecosystems Mission Area, Forest and Rangeland Ecosystem Science Center

Herbicides and herbivory interact to drive plant community and crop‐tree establishment

Land management practices often directly alter vegetation structure and composition, but the degree to which ecological processes such as herbivory interact with management to influence biodiversity is less well understood. We hypothesized that large herbivores compound the effects of intensive forest management on early seral plant communities and plantation establishment (i.e., tree survival and
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Thomas D. Stokely, Jake Verschuyl, Joan Hagar, Matthew G. Betts
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Ecosystems Mission Area, Forest and Rangeland Ecosystem Science Center

Use of created snags by cavity‐nesting birds across 25 years

Snags are important habitat features for many forest‐dwelling species, so reductions in the number of snags can lead to the loss of biodiversity in forest ecosystems. Intentional snag creation is often used in managed forests to mitigate the long‐term declines of naturally created snags, yet information regarding the use of snags by wildlife across long timescales (>20 yr) is lacking and prevents
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Amy M. Barry, Joan Hagar, James W. Rivers
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Ecosystems Mission Area, Forest and Rangeland Ecosystem Science Center

Modeling habitat for Marbled Murrelets on the Siuslaw National Forest, Oregon, using lidar data

Habitat models using lidar-derived variables that quantify fine-scale variation in vegetation structure can improve the accuracy of occupancy estimates for canopy-dwelling species over models that use variables derived from other remote sensing techniques. However, the ability of models developed at such a fine spatial scale to maintain accuracy at regional or larger spatial scales has not been te
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Joan C. Hagar, Ramiro Aragon, Patricia Haggerty, Jeff P. Hollenbeck
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Ecosystems Mission Area, Forest and Rangeland Ecosystem Science Center

Long-term dynamics and characteristics of snags created for wildlife habitat

Snags provide essential habitat for numerous organisms and are therefore critical to the long-term maintenance of forest biodiversity. Resource managers often use snag creation to mitigate the purposeful removal of snags at the time of harvest, but information regarding how created snags change over long timescales (>20 y) is absent from the literature. In this study, we evaluated the extent to wh
Authors
Amy M. Barry, Joan Hagar, James W. Rivers
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Ecosystems Mission Area, Forest and Rangeland Ecosystem Science Center

Oak mistletoe (Phoradendron villosum) is linked to microhabitat availability and avian diversity in Oregon white oak (Quercus garryana) woodlands

Mistletoes are parasitic or hemi-parasitic flowering plants that parasitize woody plants around the globe. Important food and cover resources provided by mistletoes have been related to strong patterns of positive association between wildlife diversity and mistletoe density. Mistletoes also create microhabitat features known to be important to wildlife by causing deformations in their host trees.
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Kyle R. Pritchard, Joan Hagar, David C. Shaw
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Ecosystems Mission Area, Forest and Rangeland Ecosystem Science Center

Non-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.

To request an interview, contact fresc_outreach@usgs.gov or call (541) 750-1030.

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The Snag’s the Limit: Habitat Suitability Modeling for the Western Purple Martin in a Managed Forest Landscape

The western purple martin is a species of conservation concern throughout the Pacific Northwest. 

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Excluding Grazing has Positive Effects on Riparian Vegetation, Migratory Birds

Livestock grazing can degrade riparian vegetation, altering habitat for many species of declining migratory breeding birds. At Hart Mountain National...

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New LiDAR Metrics Help Identify Habitat for the Northern Spotted Owl

The development of metrics derived from LiDAR to study forest structure has advanced wildlife-habitat modeling. 

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Herbicides and Herbivory Interactions Affect Plant Communities and Tree Survival

Land management practices often directly alter vegetation structure and composition, but the degree to which ecological processes such as herbivory...

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Use of Created Snags by Cavity-Nesting Birds Across 25 Years

Managers often intentionally create snags to mitigate the long-term declines of natural snags, yet information regarding use of created snags by...

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Science and Products

*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