Ecoregions

Blue Mountains forests

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Blue Mountains, Oregon, USA. (Photograph by Daren H. Spencer)

Introduction

caption WWF

The Blue Mountains ecoregion lies within northeastern Oregon and extreme southeastern Washington. This ecoregion consists of several basin and range areas, alluvial fans at the base of mountain ranges, and floodplains along streams draining valleys. Mountainous areas include the Strawberry, Greenhorn, Elkhorn, Aldrich, and Maury Ranges, and the Ochoco, Blue, and Wallowa Mountains. Relief is highly variable, ranging from moderate slopes in the Blue and Ochoco Mountains to the deeply dissected and glaciated Wallowa Mountains. Elevations in mountainous areas range from 2,100-2,900 meters (m), with basin areas ranging from 750-900 m. Hells Canyon is an exceptionally deep (1,660 m, deeper than the Grand Canyon) and wide (24 kilometers) canyon along the eastern boundary of the ecoregion where the Snake River cuts across the ecoregion. The western Blue Mountains contain some of the oldest rocks in Oregon dated to the Paleozoic formation. Much of the area in the central and northern portions of the ecoregion has experienced volcanic activity at some time. Soil types include regosols, fragiorthods, argixerolls, haploxerolls, and palexerolls. Major hydrologic regimes primarily influencing basin areas include the John Day, Grande Ronde, Powder, and Malheur rivers; however, low annual precipitation (305 millimeters (mm) - 1,270 mm) has limited formation of perennial streams. The ecoregion contains 11 of 116 forest and range ecosystems, including sagebrush (Artemisia tridentata), Pinyon-juniper (Juniperus occidentalis), ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii), western larch (Larix occidentalis), spruce (Picea spp.)-fir (Abies spp.), lodgepole pine (P. contorta), chaparral-mountain shrub, mountain meadows, mountain grasslands, and alpine.

Primary disturbance events include fire (various intensities and frequencies) and epizootics. A century of intensive management has created an anthropogenic landscape that bears little resemblance to the natural ecology or disturbance patterns that once shaped the region's ecosystems.

Biological Distinctiveness

In general, this ecoregion contains intermediate levels of species richness (466 species) when compared to other ecoregions within the Temperate Coniferous Forest major habitat type. Bird species make up the majority (42%) of taxa evaluated, followed by butterflies (25%), and mammals (14%). Total endemism (9 species) was relatively low compared to other ecoregions within this major habitat type.

Riparian and old growth forests represent important habitats in this region that receive disproportionate use by many fish and wildlife species. For instance, 285 of 378 (75%) terrestrial vertebrate species known to occur in the Blue Mountains either directly depend on riparian areas or use them more than other habitat types. Wildlife use riparian areas as travel corridors (e.g., for seasonal movements of ungulates between summer and winter range), as areas with favorable microclimates (e.g., shading and cooling properties benefit herpetofauna and fish), for perch and nest sites (e.g., bald eagles (Haliaeetus lecocephalus), and as feeding and roosting areas (e.g., bats, carnivores, neotropical migrants). Similarly, 174 species reproduce and 192 species feed in old growth mixed conifer forests in the region. While the total number of species in old growth is lower than in some other seral stages (e.g., grass-forb), these forests provide important refugia for 19 vertebrate species, including bald eagle, northern spotted owl (Strix occidentalis caurina), flammulated owl (Otus flammeolus), boreal owl (Aegolius funereus), Vaux's swift (Chaetura vauxi), northern goshawk (Accipiter gentilis), black-backed woodpecker (Picoides arcticus), pileated woodpecker (Dryocopus pileatus), white-headed woodpecker (P. albolarvatus), three-toed woodpecker (P. tridactylus), red-breasted nuthatch (Sitta canadensis), pygmy nuthatch (S. pygmae), brown creeper (Certhia americana), golden-crowned kinglet (Regulus satrapa), Swainson's thrush (Catharus ustulatus), hermit thrush (C. guttatus), Townsend's warbler (Dendroica townsendi), pine marten (Martes americana), and fisher (M. pennanti). Many of these species feed on insects and depend on large snags found primarily in older forests. Old growth forests also provide important source pools for species recolonization of disturbed areas and are more likely to contain intact ecological processes (e.g., nutrient cycling, hydrologic and fire regimes) and complex structural attributes (e.g., snags, down logs, diverse tree size classes) than intensively managed forests. Both riparian and old growth forest types are being rapidly depleted throughout the region because of extensive logging, livestock grazing, flood abatement, hydroelectric dams, and fire suppression.

Conservation Status

Habitat Loss

Habitat loss has been extensive, with approximately 10 percent of the region still intact (based on workshop participants’ evaluation of threats). Losses have been greatest in old growth forest types, fire-dependent forests (e.g., parklike ponderosa pine forests), riparian zones, and stream areas. Based on comparisons between current and 1936 timber inventories in the Blue Mountains, Henjum et al. document nearly a 90 percent decline in old growth ponderosa pine. Originally, virgin forests of this type extended the length of Oregon along the east slopes of the Cascade Range, from within a few kilometers of the summit to the desert's edge, interrupted only by small openings of non-forest land. Fire suppression and livestock grazing has resulted in shifts in species composition from parklike (open grassy understories) stands of large ponderosa pine to dense fir understories with accumulations of fuel loadings and more frequent conflagrations. Additional losses in low elevation old growth Douglas-fir and mixed-conifer forest types have been nearly as dramatic with most (75-90%) of remaining old-growth restricted to national forests averaging less than 0.4 square kilometers (km2). Notably, less than 8 percent of 2,888 km2 of forested roadless areas have been administratively protected. Because of their relative size (roadless areas defined by the Rare II roadless area inventory are greater than 20 km2) and composition, roadless areas represent one of the last remaining opportunities to conserve large-scale ecological processes, intact hydrologic regimes, and species that are intolerant of road-related impacts (e.g., large carnivores). Roadless areas are also important benchmarks for gaging the effectiveness of restoration and ecosystem management activities.

In addition to losses in the above forested types, aquatic areas also have been highly degraded throughout the region. Forty-three taxa of resident fish have been identified as at risk of extinction within the region due to extensive habitat degradation. For instance, since 1941, 60 percent of the pool habitat for fish on the Grande Ronde River in Oregon has been degraded and more than 70 percent of the streams in the Wallowa Whitman National Forest on the Upper Grande Ronde fail to meet forest plan standards. On the John Day River in Oregon, fall chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) appear to be extinct and spring chinook salmon and steelhead (O. mykiss) numbers have dropped precipitously. The bull trout (Salvelinus confluentus) has experienced extensive declines in spawning habitat and is a species of concern and a candidate for listing under the Endangered Species Act. Additional threats in this region include exotic species invasions, shifts in plant community composition related to fire suppression and livestock grazing, and changes in hydrologic and stream temperature regimes that have disrupted food webs and ecological processes within riparian zones, aquatic areas, and adjacent uplands.

Remaining Blocks of Intact Habitat

As discussed, few old growth areas in this region are large enough to sustain dependent species or ecological processes; however, roadless areas represent the best opportunities for maintaining examples of relatively intact ecosystems. Workshop participants listed the following priority areas for conserving representative blocks of intact habitat:

  • Eagle Gap Wilderness, Wallow Whitman National Forest - northeastern Oregon - 1,280 km2
  • Hells Canyon National Recreation Area - northeastern Oregon - 1,370 km2
  • North Fork of the John Day River - north-central Oregon - 454 km2
  • Wenaha-Tucannon area, Umatilla National Forest - northeastern Oregon and southeastern Washington - 714 km2
  • Strawberry Mountain, Malheur National Forest - eastern Oregon - 280 km2

Additional roadless areas, wilderness areas, and old growth forests requiring protection are provided in Henjum et al. Henjum et al. provide the foundation for restoration and conservation planning activities within the region.

Degree of Fragmentation

Habitat fragmentation has been extensive in this ecoregion; however, the southern portion is more heavily fragmented and altered than the northern portion (based on workshop participants’ evaluation of threats). Most forests in this ecoregion could be restored if logging were curtailed (especially in old growth and other declining types), livestock grazing were greatly reduced (especially in riparian areas and parklike ponderosa pine forests), if some fires were allowed to burn (e.g., in wilderness areas and forests that have not had fire regimes significantly altered by fire suppression), and prescribed fires were used to return fire cycles to historic conditions. Restoration activities should use remaining native habitats (e.g., roadless areas, old growth) as benchmarks in adaptive management approaches combined with prescribed fire and limited thinning in fire-suppressed forest types (e.g., thinning-from-below the dominant canopy). Such activities would be useful in directing landscape trajectories to recreate patch and disturbance patterns more characteristic of pre-European settlement conditions.

Degree of Protection

According to Henjum et al., unless logging ceases in old growth ponderosa pine this forest type will decline below 10 percent of its historic extent within the foreseeable future. Although President Clinton commissioned the Forest Service and Bureau of Land Management to conduct a basin-wide (Columbia River basin planning includes the Blue Mountains) scientific assessment and environmental impact statement, salvage logging and fire suppression activities continue to threaten remaining old growth and roadless areas, further jeopardizing opportunities for restoration and conservation. While some remaining roadless areas and old growth have ostensibly been evaluated for their contribution in maintaining biodiversity, it is unclear whether these areas will be administratively protected or will be subject to Congressional attempts to overturn forest planning (e.g., forest health legislation proposed by Senator Craig continues to threaten roadless and old growth areas).

Type and Severity of Threats

Workshop participants identified the rapid rate of logging in remaining old growth and roadless areas as the greatest threat to biodiversity in the ecoregion, followed by overgrazing. Forest health measures legislated by Congress (e.g., salvage logging law, PL 104-19) and conducted by federal agencies as part of ecosystem management approaches continue to focus narrowly on tree mortalities at the expense of ecosystem functions, processes, and integrity. Large-scale salvage logging as a treatment for perceived forest health emergencies continues to pose the greatest threat to ecosystem integrity in the region. The Blue Mountains have received the most attention regarding forest health because of recent increases in conflagrations and epizootics. However, much of the forest health problems in this region have been caused by a century of intensive management that has reduced ecosystem resiliency, eliminated complex structural features important to insectivorous species (e.g. snags, large trees) and fire resistant trees, and substantially altered fire and hydrologic regimes. Other threats to biodiversity in the region include exotic species invasions and potential regional shifts in climatic patterns related to predicted global climate change. These threats are similar to threats identified in surrounding ecoregions within this major habitat type.

Suite of Priority Activities to Enhance Biodiversity Conservation

Workshop participants identified the following priority activities that along with recommendations of Henjum et al. and DellaSala et al. provide a basis for restoration and conservation planning in this ecoregion:

  • Protect all remaining large, relatively intact blocks, including Hells Canyon and Eagle Cap; John Day wilderness and surrounding areas; Wenaha-Tucannon wilderness; Aldrich Mountain (northwest corner of Malheur National Forest has old growth but most is unprotected); and Ochoco National Forest (northern block has unprotected old growth).
  • Protect all old growth, roadless areas, and aquatic diversity areas identified by Henjum et al. and do not construct roads in any roadless areas, particularly those of more than 2.5 km2.
  • Cut no trees of any species older than 150 years or with a diameter-at-breast height greater than 50 centimeters (cm), and no ponderosa pine dominant or codominants from any forest.
  • Conduct restoration activities, including thinning-from-below and prescribed fire management in areas where fire suppression has caused excessive accumulation of fuels and dense fir understories (e.g., fire-suppressed ponderosa pine forests).
  • Conduct restoration activates in riparian areas, including road closures, road obliteration, and reductions in livestock grazing pressure.
  • Establish protected corridors along streams, rivers, lakes, and wetlands and restrict logging and grazing activities within these corridors.
  • Halt salvage logging activities in ecologically sensitive areas, including areas recovering from intense fire, unstable slopes, fragile soils, riparian areas, and old growth.
  • Base forest health assessments on the health and integrity of entire ecosystems and not only tree mortalities.
  • Establish a forest health monitoring program that is based on appropriate indices of ecological integrity (e.g., degree of fragmentation, presence of intact terrestrial and hydrological processes) and biodiversity conservation.

The above recommendations also apply to surrounding ecoregions within this major habitat type.

Conservation Partners

  • Association of Forest Service Employees for Environmental Ethics
  • Clearwater Forest Watch
  • Inland Empire Public Lands Council
  • Kettle Range Conservation Group
  • Klamath Forest Alliance
  • National Wildlife Federation
  • Northwest Ecosystem Alliance
  • Pacific Rivers Council, Oregon
  • Selkirk-Priest Basin Association
  • Key individuals include: Dr. James Karr, Dr. Bill Romme, and Dr. Dave Perry

Relationship to Other Classification Schemes

The Blue Mountain ecoregion mapped in this assessment was based on Omernik's ecoregion #11. This ecoregion is roughly concordant with Bailey's classification, with the exception of the southeast and northwest corners that were split into different ecoregions by Bailey. The ecoregion generally corresponds to Franklin and Dyrness' description of the Blue Mountains Province and Thomas' et al. description of wildlife and plant communities in the Blue Mountains.

Additional Information on this Ecoregion

 

 

 

Disclaimer: This article is taken wholly from, or contains information that was originally published by, the World Wildlife Fund. Topic editors and authors for the Encyclopedia of Earth may have edited its content or added new information. The use of information from the World Wildlife Fund should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.

 

Glossary

Citation

Fund, W. (2014). Blue Mountains forests. Retrieved from http://www.eoearth.org/view/article/150702

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