By CIRCulator Editorial Staff
Reprinted from: The Climate CIRCulator
RANGING IN ELEVATION from 267 to 3,000 meters (roughly 875 to 10,000 feet) and nestled in the corner of northeast Oregon and southeast Washington, the Blue Mountains are a collection of small mountain ranges that comprise a rich, complex ecosystem of forests, streams, and snow-capped peaks. As with other mountain ecosystems in the U.S. West and Northwest, the Blue Mountains face impacts from a warming and changing climate that threatens to lower snowpack and increase the risk of wildfires.
The U.S. Forest Service is responding to these and other climate threats to the Blue Mountains with an ambitious effort called the Blue Mountains Adaptation Partnership, or BMAP. Recently project mangers for BMAP released a comprehensive climate assessment and adaptation plan for the mountain ecosystem. Here are some of the highlights from the study’s findings on impacts and possible adaptation strategies.
As with other mountain ecosystems across the U.S. West, the Blue Mountains’ climate change impacts revolve to a large extent around how a warming climate is expected to change the region’s mountain hydrology. Compared to the historical record, temperatures in the region are expected to be anywhere from 3.2° to 6.3° Celsius (5.7° to 11.3° Fahrenheit) warmer by the year 2100, and 2.4° to 3.1° C (4.3° to 5.6° F) warmer by the middle of this century. This increased warming is expected to make it far more likely for precipitation to fall as rain instead of as snow, producing far-reaching effects ranging from washed out roads to making streams potentially too warm for salmon as well as leading to especially dry summers that are expected to greatly increase the likelihood of forest fires. For each impact they note, the researchers proposed a series of adaptation strategies.
Water Availability and Infrastructure
- Impacts: Much of the West and Northwest rely on melting snowpack to get through the long, dry summers. This is true of fish, farmers, and forests. The Blue Mountains are no exception. Declining snowpack is expected to disrupt the mountains’ hydrologic processes, with summer flows in the mountains expected to decline. The annual timing of steam flows will also change, with greater flows expected during the rainy season in the winter and the spring.
- Impacts: The increase in the magnitude of wintertime stream flows (winter is already the period of peak stream flows) is expected to overwhelm area infrastructure, leading to damaged roads near streams. Damage will range from minor erosion to the complete loss of roads, according to the report’s authors.
- Adaptations: To lessen the effects of these impacts, the report suggests that resource managers should respond by restoring—by as much as they can—the function of area watersheds and reducing the drainage from higher elevations where possible. To do this, the report suggests adaptation strategies such as adding wood to streams, restoring beaver populations, reconnecting floodplains, and reducing fire hazards by thinning tree stands. To shore up the region’s infrastructure, the authors recommend moving roads away from streams and strengthening and increasing the size of culverts.
- Impacts: Disappearing snowpack and the havoc it will produce—increasing winter peak stream flows and further lowering summer low flows—are expected to combine with higher air temperatures to increase stream temperatures. This is expected to be detrimental to cold-water fish species such as salmon and trout. In particular, current populations of Chinook salmon and redband and steelhead trout will be especially hard hit, seeing significant reductions in their numbers. (Here, the researchers’ work relied in part on that of biologist Dan Isaak. See the CIRCulator article “Trout Need Cold, Wide, Connected Waters.”)
- Adaptations: Possible ways to lessen the impacts on fish proposed by the authors include: keeping area stream networks connected so fish can migrate as needed, repairing riparian habitats, maintaining summer base flow by reintroducing and aiding beaver populations, instituting strategies to reduce forest fires via thinning, and replanting in burned areas to help prevent runoff and sediment loading from occurring in the streams.
Forests and Vegetation
- Impacts: Rising temperatures are expected to impact soil moisture, gradually changing the number, distribution, and type of trees and other plants growing throughout the Blue Mountains. Other drivers of vegetation change in the region will include wildfires and insect outbreaks.
- Adaptations: Potential adaptations to the above impacts revolve around ways to reduce the severity and size of disturbances. Here, the authors recommend tree management techniques such as thinning and revising grazing practices to reduce fuel loads. A more far-reaching suggestion includes changing where trees and other plants are replanted following a disruption to reflect changes in ranges due to a warming climate. It’s widely understood that under climate change rising temperatures are expected to create less favorable climates for existing vegetation, potentially rearranging plant species in the Northern Hemisphere.
Within their boundaries, the Blue Mountains contain three national forests, Malheur National Forest, Umatilla National Forest, and Wallowa-Whitman National Forest. Starting roughly two years ago, representatives from these forests teamed up with researchers from CIRC, the University of Washington, and the U.S. Forest Service Pacific Northwest Station, including Jessica Halofsky, the BMAP report’s lead author, and research biologist Dave Peterson, to create a comprehensive climate change assessment and adaptation plan for the forests. Peterson is this month’s featured researcher.
BMAP is part of a larger effort by Peterson and the Forest Service called Adaptation Partners, an endeavor that seeks to connect Forest Service researchers and resource managers with regional climate scientists and stakeholders in order to help resource managers in the Forest Service adapt to climate change on a forest-by-forest basis. In total, six adaptation partnerships have been kicked off and are in various states of completion as part of the Adaptation Partners project. A seventh partnership, the Olympic Adaptation Partnership, was also completed as a kind of beta run for the current six projects. Along with the Blue Mountain Adaptation Partnership, CIRC also participated in the Northern Rockies Adaptation Partnership. Results from that project are expected next year.
Citation: Halofsky, J.E., Peterson, D.L. “Climate Change Vulnerability and Adaptation in the Blue Mountains Region (final report).” U.S. Department of Agriculture, Forest Service, Pacific Northwest Station. (2015)