Klamath Mountains (ecoregion)

This article is about the Klamath Mountains ecoregion. For the mountain range, see Klamath Mountains.

Klamath Mountains
Bear Mountain in the Siskiyou Wilderness of California

Ecology
Biome	Temperate coniferous forests
Borders	Coast Range Willamette Valley Cascades Sierra Nevada Southern and Central California Chaparral and Oak Woodlands Eastern Cascades Slopes and Foothills
Bird species	220^[1]
Mammal species	87^[1]
Geography
Area	50,245 km² (19,400 sq mi)
Country	United States
States	California and Oregon
Coordinates	41°30′N 123°18′W / 41.5°N 123.3°W / 41.5; -123.3Coordinates: 41°30′N 123°18′W / 41.5°N 123.3°W / 41.5; -123.3
Conservation
Habitat loss	4.4045%^[1]
Protected	56.99%^[1]

The Klamath Mountains ecoregion of Oregon and California lies inland of the Coast Range ecoregion, extending from the Umpqua Valley in the north to the Sacramento Valley in the south. It encompasses the highly dissected ridges, foothills, and valleys of the Klamath and Siskiyou Mountains. It corresponds to the Level III ecoregion designated by the United States Environmental Protection Agency (EPA) and to the Klamath-Siskiyou forests ecoregion designated by the World Wide Fund for Nature.^[2]

The ecoregion was unglaciated during the Pleistocene epoch, when it served as a refuge for northern plant species. Its mix of granitic, sedimentary, metamorphic, and extrusive rocks contrasts with the predominantly volcanic rocks of the Cascades ecoregion to the northeast. The mild, subhumid climate of the region is characterized by a lengthy summer drought. It supports a mosaic of both northern Californian and Pacific Northwestern conifers and hardwoods.^[3]

The Klamath Mountains ecoregion is a vast, well-protected region that is sparsely populated. While the Klamath Mountains do not have the charismatic mega-fauna that make other National Parks or vast wilderness areas attractive to visitation, the plant diversity offers an enjoyable hiking experience.

Ecology

The ecoregion harbors rich biodiversity,^[4] with several distinct plant communities, including temperate rain forests, moist inland forests, oak forests and savannas, high elevation forests, and alpine grasslands. Thirty conifer species inhabit the region, including seven endemic species, making the region one of the richest coniferous forest regions of the world in species diversity. The region also has several edaphic plant communities, adapted to specific soil types, notably serpentine outcrops.

Conifer species include Coast Douglas-fir (Pseudotsuga menziesii subsp. menziesii), Lawson's Cypress (also known as Port Orford Cedar, Chamaecyparis lawsoniana), Ponderosa Pine (Pinus ponderosa), Sugar Pine (Pinus lambertiana), Mountain Hemlock (Tsuga mertensiana), White Fir (Abies concolor subsp. lowiana), Red Fir (A. magnifica subsp. shastensis), Weeping Spruce (Picea breweriana), Coast Redwood (Sequoia sempervirens), and Pacific Yew (Taxus brevifolia). These forests mark the northern extent of the range for California Buckeye.^[5]

Level IV ecoregions

Level IV ecoregions in the Klamath Mountains in Oregon. Contiguous areas in California have not been mapped yet. (Full map).

The Oregon portion of the ecoregion has been subdivided into seven Level IV ecoregions, as described below.

Rogue/Illinois Valleys (78a)

The Rogue/Illinois Valleys ecoregion includes terraces and floodplains in the Rogue and Illinois river valleys at an elevation of 900 to 2,000 feet (274 to 610 m). Historically, the valleys supported Oregon white oak and California black oak woodland, with Pacific madrone, ponderosa pine, and grassland. Common understory plants included California fescue, snowberry, and serviceberry. Riparian areas supported willow and cottonwood. Much of the land has been developed for agricultural or residential use, and little of the original vegetation remains. Remnants of oak savanna, prairie vegetation, and seasonal ponds persist on the mesa tops of the Table Rocks north of Medford. Elsewhere, land uses include orchards, cropland, and pastureland. Climate, vegetation, and resulting land use are more similar to Northern California’s inland valleys than to the Willamette Valley ecoregion to the north. The region covers 285 square miles (738 km²) in Oregon, in three separate areas around Medford and Ashland, Grants Pass, and Cave Junction.^[3]

Oak Savanna Foothills (78b)

The Oak Savanna Foothills ecoregion consists of moderately sloping mountain foothills bordering the Rogue and Illinois river valleys and sharing their Mediterranean climate. Elevation varies from 1,400 to 4,000 feet (427 to 1,219 m). The driest area, east of Medford, is dominated by Oregon white oak and California black oak woodlands, grassland-savanna, ponderosa pine, and Coast Douglas-fir. The wetter foothills flanking the Illinois Valley support Douglas-fir, madrone, and California incense-cedar. Understory species include oceanspray, Western poison-oak, snowberry, Idaho fescue, California brome, roughstalk bluegrass, and ceanothus. The region is lower and less dissected, with more oak woodland and less closed-canopied forest than the Inland Siskiyous. It covers 818 square miles (2,119 km²) in Oregon.^[3]

Umpqua Interior Foothills (78c)

The Umpqua Interior Foothills ecoregion is a complex of foothills and narrow valleys containing fluvial terraces and floodplains. Elevation varies from 400 to 2,800 feet (122 to 853 m). It is drier than the foothills of the Willamette Valley, partly because the summer Pacific high pressure system arrives earlier and remains longer than in ecoregions to the north. Summers are hot and dry, and soils have a xeric moisture regime in contrast to the udic soils of the Mid-Coastal Sedimentary ecoregion to the west. The slopes are covered by Oregon white oak woodland, Douglas-fir, grand fir, ponderosa pine, madrone, tanoak, and chinkapin, with an understory chaparral community that includes snowberry, salal, Oregon grape, poison oak, oceanspray, and swordfern. Many areas have been converted to pastureland, vineyards, orchards, and row crops. It covers 921 square miles (2,385 km²) in Oregon in the Umpqua Valley, including the city of Roseburg.^[3]

Waldo rockcress is an uncommon endemic member of the serpentine soils flora of the Serpentine Siskiyous.

Serpentine Siskiyous (78d)

The Serpentine Siskiyous ecoregion consists of highly dissected mountains containing perennial, high gradient streams at an elevation of 1,500 to 4,300 feet (457 to 1,311 m). It is lithogically distinct from the rest of the Klamath Mountains ecoregion. Many plants have difficulty growing in its serpentine soils due to a shortage of calcium and high levels of magnesium, nickel, and chromium. As a result, vegetation is often sparse and composed of specialist species that have evolved to grow in the potentially toxic and nutrient-poor serpentine soils. It supports a mixed conifer forest of Jeffrey pine, tanoak, incense-cedar, Douglas-fir, and montane chaparral composed of manzanita, ceanothus, Idaho fescue, and Lemmon needlegrass. Historic gold, nickel, chromite, copper, and mercury mining have contributed to water quality problems. The region covers 440 square miles (1,140 km²) in Oregon, including portions of the Rogue River – Siskiyou National Forest and the Kalmiopsis and Wild Rogue wildernesses. Contiguous areas in California have not been mapped yet.^[3]

Inland Siskiyous (78e)

Preston Peak, Siskiyou Wilderness

The Inland Siskiyous ecoregion is higher and more mountainous than the neighboring foothill and valley ecoregions, with an elevation of 800 to 7,000 feet (244 to 2,134 m). It has a higher fire frequency, less annual precipitation, and longer summer droughts than the Coastal Siskiyous. Forest cover is a diverse and multi-layered mix of conifers, broadleaf evergreens, and deciduous trees and shrubs, featuring Douglas-fir, ponderosa pine, Oregon white oak, California black oak, madrone, serviceberry, snowberry, Oregon grape, California fescue, and poison oak. The largest of the Klamath Mountains subregions mapped so far, it covers 2,610 square miles (6,760 km²) in Oregon, including public lands within the Rogue River – Siskiyou National Forest. Contiguous areas in California have not been mapped yet.^[3]

Coastal Siskiyous (78f)

The Coastal Siskiyous ecoregion consists of highly dissected mountains with a wetter and milder maritime climate than elsewhere in the Klamath Mountains ecoregion. Elevation varies from 600 to 5,300 feet (183 to 1,615 m). Productive forests composed of tanoak, Douglas-fir, bigleaf maple, California laurel, and some Port Orford cedar cover its mountainous landscape, with chinkapin, salal, rhododendron, and swordfern; tanoak is more common than elsewhere in Oregon. Broadleaf evergreens, such as tanoak and madrone, quickly colonize disturbed areas, making it difficult to regenerate conifer forest growth. Xeric soils derived from Siskiyou rock types are characteristic; udic soils which support western hemlock and Sitka spruce are present but are less common than in the wetter Coast Range ecoregion to the west. The region covers 853 square miles (2,209 km²) in Oregon, including portions of the Rogue River – Siskiyou National Forest and the Kalmiopsis and Wild Rogue Wilderness wildernesses. Contiguous areas in California have not been mapped yet.^[3]

Klamath River Ridges (78g)

The Klamath River Ridges is characterized by highly dissected mountains, with a dry, continental climate. Elevation varies from 3,800 to 7,500 feet (1,158 to 2,286 m). Vegetation varies with slope, aspect, and elevation. Higher altitudes and north-facing slopes have Douglas-fir and white fir; lower elevations and south-facing slopes are covered in ponderosa pine and western juniper, species that are more drought-resistant than other vegetation types found within the region. The chaparral features Oregon grape, western fescue, snowberry, bluebunch wheatgrass, and ceanothus. The region covers 121 square miles (313 km²) in Oregon near the Siskiyou Summit, including portions of the Rogue River – Siskiyou National Forest and the Cascade–Siskiyou National Monument. Contiguous areas in California have not been mapped yet.^[3]

References

↑ 1.0 1.1 1.2 1.3 Hoekstra, J. M.; Molnar, J. L.; Jennings, M.; Revenga, C.; Spalding, M. D.; Boucher, T. M.; Robertson, J. C.; Heibel, T. J.; Ellison, K. (2010). Molnar, J. L., ed. The Atlas of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. University of California Press. ISBN 978-0-520-26256-0.
↑ "Klamath-Siskiyou forests". Terrestrial Ecoregions. World Wildlife Fund.
↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 This article incorporates public domain material from the United States Geological Survey document: Thorson, T.D., Bryce, S.A., Lammers, D.A. et al. "Ecoregions of Oregon". (color poster with map, descriptive text, summary tables, and photographs; with a Reverse side).
↑ Norse, Elliott A.; Raven, Peter H. (1989). Ancient Forests of the Pacific Northwest: Sustaining Biological Diversity and Timber Production in a Changing World. Wilderness Society (U.S.). Washington, D.C.: Island Press. ISBN 1-55963-016-7.
↑ Hogan, C.Michael (2008). "Aesculus californica". Globaltwitcher.com. N. Stromberg.

External links

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Klamath Mountains (category)

Level III Ecoregions in Oregon

Marine West Coast Forest	1 Coast Range 3 Willamette Valley

Northwestern Forested Mountains	4 Cascades 9 Eastern Cascades Slopes and Foothills 11 Blue Mountains 78 Klamath Mountains

North American Deserts	10 Columbia Plateau 12 Snake River Plain 80 Northern Basin and Range

as defined by the United States Environmental Protection Agency

Level III Ecoregions in the United States

Marine West Coast Forest	1 Coast Range 2 Puget Lowland 3 Willamette Valley 111 Ahklun and Kilbuck Mountains 113 Alaska Peninsula Mountains 115 Cook Inlet 119 Pacific Coastal Mountains 120 Coastal Western Hemlock-Sitka Spruce Forests

Northwestern Forested Mountains	4 Cascades 5 Sierra Nevada 9 Eastern Cascades Slopes and Foothills 11 Blue Mountains 15 Northern Rockies 16 Idaho Batholith 17 Middle Rockies 19 Wasatch and Uinta Mountains 21 Southern Rockies 41 Canadian Rockies 77 North Cascades 78 Klamath Mountains 105 Interior Highlands 116 Alaska Range 117 Copper Plateau 118 Wrangell Mountains

Mediterranean California	6 Southern and Central California Chaparral and Oak Woodlands 7 Central California Valley 8 Southern California Mountains

North American Deserts	10 Columbia Plateau 12 Snake River Plain 13 Central Basin and Range 14 Mojave Basin and Range 18 Wyoming Basin 20 Colorado Plateaus 22 Arizona/New Mexico Plateau 24 Chihuahuan Deserts 80 Northern Basin and Range 81 Sonoran Basin and Range

Temperate Sierras	23 Arizona/New Mexico Mountains

Great Plains	25 Western High Plains 26 Southwestern Tablelands 27 Central Great Plains 28 Flint Hills 29 Central Oklahoma/Texas Plains 30 Edwards Plateau 31 Southern Texas Plains 34 Western Gulf Coastal Plain 40 Central Irregular Plains 42 Northwestern Glaciated Plains 43 Northwestern Great Plains 44 Nebraska Sand Hills 45 Piedmont 46 Northern Glaciated Plains 47 Western Corn Belt Plains 48 Lake Agassiz Plain

Eastern Temperate Forest	32 Texas Blackland Prairies 33 East Central Texas Plains 35 South Central Plains 36 Ouachita Mountains 37 Arkansas Valley 38 Boston Mountains 39 Ozark Highlands 51 North Central Hardwood Forests 52 Driftless Area 53 Southeastern Wisconsin Till Plains 54 Central Corn Belt Plains 55 Eastern Corn Belt Plains 56 Southern Michigan/Northern Indiana Drift Plains 57 Huron/Erie Lake Plains 59 Northeastern Coastal Zone 60 Northern Appalachian Plateau and Uplands 61 Erie Drift Plain 63 Middle Atlantic Coastal Plain 64 Northern Piedmont 65 Southeastern Plains 66 Blue Ridge 67 Ridge and Valley 68 Southwestern Appalachians 69 Central Appalachians 70 Western Allegheny Plateau 71 Interior Plateau 72 Interior River Valleys and Hills 73 Mississippi Alluvial Plain 74 Mississippi Valley Loess Plains 75 Southern Coastal Plain 82 Laurentian Plains and Hills 83 Eastern Great Lakes and Hudson Lowlands 84 Atlantic Coastal Pine Barrens

Northern Forests	49 Northern Minnesota Wetlands 50 Northern Lakes and Forests 58 Northeastern Highlands 62 North Central Appalachians

Tropical Wet Forests	76 Southern Florida Coastal Plain

Southern Semi-Arid Highlands	79 Madrean Archipelago

Taiga	101 Arctic Coastal Plain 102 Arctic Foothills 103 Brooks Range 104 Interior Forested Lowlands and Uplands 106 Interior Bottomlands 107 Yukon Flats 108 Ogilvie Mountains

Tundra	109 Subarctic Coastal Plains 110 Seward Peninsula 112 Bristol Bay-Nushagak Lowlands 114 Aleutian Islands

as defined by the United States Environmental Protection Agency