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Studying Birds to Inform Stewardship on National Forest Lands

Hitching Science and Management in the Sierra

Ryan Burnett, Nat Seavy, and Jay Roberts

The Sierra Nevada mountains, with their oak woodlands, alpine meadows, majestic conifer forests, snow-capped peaks, and sagebrush flats, are a natural treasure. Today, Yosemite National Park is globally recognized, in part through the writings of John Muir and photographs of Ansel Adams, for its dramatic landscapes and the biodiversity it protects. Less well-recognized, but covering a much larger area, are vast expanses of public land managed by the U.S. Forest Service. While these lands once were managed primarily for the extraction of natural resources (timber and minerals, for example), management today is shifting toward a more holistic approach. Newer strategies recognize the importance of biodiversity and of ecosystem services (the benefits of natural processes to human society). This shift requires new sources of information that can be used in shaping decisions about management.
A young Lewis's Woodpecker, fresh out of the nest cavity, surveys its world. Photo by Tom Grey (

Integrating results from avian research into management actions is at the heart of conservation science and one of its greatest challenges. For 13 years, PRBO has been working with public land managers to weave results from avian monitoring into the fabric of Sierra Nevada management. As part of this process, we have produced many tools: interactive web-based programs that enable managers to view and explore our data in a timely manner; statistical models that help managers identify important areas for birds; user-friendly management guides; and traditional reports and peer-reviewed publications. Without a doubt, however, our most important contributions have been through direct, face-to-face interactions with land managers.

These direct interactions have been paramount in our effort to integrate PRBO's science into on-the-ground management. The process requires not only regular engagement with land managers but also that our staff have a detailed understanding of the ecological systems in which we work. This local knowledge ensures that our recommendations are targeted, relevant, timely, and trustworthy. Whether evaluating aspen restoration or helping design fuel reduction treatments, our long-term data sets and consistent presence in the places where we work have helped us build bridges between research and management.

This is an exciting time in PRBO's Sierra Nevada program, as we embark on two new projects in which we will work with land managers throughout this huge mountain region. Our ambitious Sierra-wide Management Indicator Species project spans approximately six million acres of national forest land that extends from the Oregon border south more than 400 miles. In addition, a new post-fire habitat study on the Lassen and Plumas national forests aims to answer "burning" questions about how to manage post-fire habitats for birds.

The following sections survey the goals and scope of two Sierra Nevada projects that are beginning in summer 2009.

Valuable Post-fire Habitats

As we know from the evening news, wildfires occur throughout the Sierra Nevada forests each summer. While media coverage of these events often describes them with words such as "catastrophic" and "devastating," many birds that reside in the Sierra would consider wildfire anything but devastating. Fire serves a vital function in supporting biodiversity. Fire and post-fire management alike have important consequences for wildlife, including some birds that are now declining—Chipping Sparrow and Lewis's Woodpecker, for example. In the first few years after a fire, management decisions shape the composition and structure of the forest into the future.
Post-wildfire habitat in the Sierra Nevada. Photo by Brendan McGarry.

To improve conditions for birds and other wildlife, PRBO is setting out to use our research results to help guide the management of post-fire environments to best sustain healthy bird populations.

After every forest fire, managers make a complex set of decisions about how to treat the burned area. Actions may include removing dead and dying trees for timber (salvage logging), planting young trees, and removing shrubs and other understory vegetation to hasten the return to forested conditions. It is certainly important that great Sierran conifer forests persist into the future—for many reasons, including the ecosystem services they provide (carbon sequestration, timber products, oxygen production and water storage, for example).

Within the Sierran sea of conifers, however, a suite of wildlife species relies upon the islands of non-conifer forest habitats that fire creates. PRBO's current work on post-fire habitats will help ensure this valuable diversity is maintained.
Chipping Sparrow is among the species affected by fire and post-fire management. Photo by Tom Grey.

One component of our work involves understanding what types of dead and dying trees—snags—are important to birds. As many as ten woodpecker species occur within post-fire habitats in our Lassen and Plumas national forest study area; so do other cavity-nesting birds, such as the Mountain Bluebird.

Not only do snags provide nesting habitat for many species: seen through a woodpecker's eyes, they must seem like vertical pole-shaped dinner plates. Snags and dying trees are teeming with bark beetles and other insects that many avian species eat. By understanding what types and quantities of snags are needed by woodpeckers and other cavity-nesting birds, we aim to provide land managers with information they can use to plan salvage logging operations that retain habitat for post-fire bird species.

In addition to creating snags, wildfires in the Sierra Nevada allow broadleaf trees and shrubs—oaks, California lilacs (ceanothus) and manzanita, for example—to proliferate. Often, managers promote the establishment of conifer trees by removing broadleaf plants. Many shrub-associated birds, though, reach their greatest abundance in these post-fire broadleaf-dominated habitats. Some examples are Lazuli Bunting, Nashville Warbler, Chipping Sparrow, and Fox Sparrow. We are developing quantitative habitat models1 for such species and management guidelines that address habitat needs of broadleaf-associated birds.

PRBO is in its second decade of work in the Sierra Nevada, providing the Forest Service with feedback to help manage conifer forests, hardwoods, and meadows. By focusing attention on post-fire habitats, our new effort will enlarge the scientific basis for managing this ecologically diverse system.

Birds as Management Indicators

For a vast portion of the Sierra Nevada's expanse—more than ten million acres—the U.S. Forest Service (USFS) has natural resource management responsibilities. Each year, natural events and human activities throughout the region influence wildlife habitat: fires burn; timber is harvested, roads are built and maintained, and cattle are grazed. While the managers of each forest unit are responsible for evaluating the impacts of specific activities on wildlife habitat, to date there have been few efforts to track the cumulative effects across the entire region. This year, PRBO has entered into an exciting new partnership with the USFS to monitor certain bird species as indicators of management practices across the entire Sierra Nevada—no small task!

"Our partnership with PRBO is very much a relationship to have pride in." —Tom Frolli, Lassen National Forest
Hairy Woodpecker at nest cavity. Photo by Tom Grey.

The Forest Service chose species that represent habitat types within national forest boundaries and are thought to be sensitive to USFS management activities. Among the birds to be surveyed are Yellow Warbler (an indicator of riparian habitat), Mountain Quail (conifer forest at middle stages of succession), Fox Sparrow (chaparral), and Hairy Woodpecker (forest snags).

Jay Roberts, PhD, joined our staff in January 2009 to lead this new project along with PRBO's Sierra Program Director Ryan Burnett. From day one, Jay took on a remarkably large study area. "This collaborative project is notable in many ways," he explains, "especially its spatial scale. Using maps of target habitats, we've selected over 2,000 survey locations in over six million acres of USFS land, from Modoc National Forest in the north to Sequoia National Forest in the south." In May of this year, Jay deployed 12 PRBO field biologists to begin surveys on nine National Forests and the Lake Tahoe Basin Management Unit.

The project's goal is to help the USFS track patterns in the distribution of the indicator species over time—to help the agency better manage their lands. Planners and managers will use PRBO's results to modify management activities as needed: a decline in the population of Fox Sparrows, for example, could suggest that management strategies for chaparral habitats need to be modified. Revised management plans for each of these national forests can directly incorporate recommendations derived from our studies of bird indicators.

Also affecting wildlife habitats and species, there are complex forces at work from within and beyond national forest boundaries. These forces include climate change, development, private land management, and invasive species. So, in addition to providing feedback to the USFS on their management activities, PRBO aims to identify other factors influencing bird populations across the entire Sierra Nevada ecosystem over time.
Aspen groves and meadows are among the habitats within the "conifer sea" in the Sierra. Photo by Ryan Burnett.

Notes Jay Roberts, "Since our samples are spread out over ten distinct national forest management areas, we can use Sierra-wide patterns to inform decisions on the local or forest-unit scale—decisions that are typically made independently."

Managing diverse habitats for birds, other wildlife, and healthy ecosystems in the Sierra Nevada is not an easy proposition. This effort requires an understanding of how management activities will change habitats and the bird species they support, and also how these local and regional changes are influenced by large-scale environmental change. The ambitious collaboration between USFS managers and PRBO scientists holds the promise for effective and coordinated management across the entire Sierra Nevada region—and is one powerful mechanism that can help make the effort succeed.

Also contributing to this Observer were Tom Gardali (Associate Director, Terrestrial Ecology) and Melissa Pitkin (Director, Education and Outreach).