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Section M261E
Sierra Nevada
This
section is the temperate to very cold parts of the Sierra Nevada, which
is a north-northwest aligned mountain range that is much steeper on the
east than on the west side.� It is in MLRA 22.
Geomorphology.� Block mountain range tilted west; accordant
crests.� Sierra Nevada Range geomorphic province.
Lithology.� Mesozoic granitic and ultramafic rocks, Paleozoic
and Mesozoic strongly metamorphosed sedimentary and volcanic rocks, and
Cenozoic volcanic rocks.
Soil Taxa.� Alfisols, Andisols, Aridisols, Entisols, Inceptisols,
Mollisols and Ultisols in combination with mesic, frigid or cryic soil
temperature regimes and xeric, udic, aridic or aquic soil moisture regimes.
Vegetation.� Predominant potential natural communities include
the Mixed conifer series, Ponderosa pine series, Jeffrey pine series, White
fir series, Red fir series, Lodgepole pine series, Huckleberry oak series,
Western Juniper series, Aspen series, Big sagebrush series, Mixed subalpine
forest series, Mountain hemlock series, Whitebark pine series and Giant
sequoia series.
The following series are found throughout the section and are not restricted
to or extensive in any subsection. Series dominated by exotic plants are
not listed under subsections unless they are extensive and stable.
Series dominated by exotic plants: Broom series, California
annual grassland series, Cheatgrass series, Introduced perennial grassland
series, Kentucky bluegrass series and Tamarisk series.
Series that can occur in all subsections, but are not extensive:
Bulrush series, Bulrush - cattail series, Bur-reed series, Common reed
series, Cattail series, Creeping ryegrass series, Ditch-grass series, Duckweed
series, Holodiscus series, Mosquito fern series, One-sided bluegrass series,
Pondweeds with floating leaves series, Pondweeds with submerged leaves
series, Quillwort series, Saltgrass series, Sedge series, Spikerush series,
Tufted hairgrass series and Yellow pond-lily series.
Series restricted to riparian settings: Black cottonwood series,
Mixed willow series, Montane wetland shrub habitat, Mountain alder series,
Narrowleaf willow series, Pacific willow series, and Red willow series.
Fauna.� Mammals include black-tail and mule deer, black bear,
mountain lion, coyote, bobcat, red and gray fox, ringtail, weasels, skunks,
badger, mountain sheep, yellow-bellied marmot, marten, fisher, wolverine
and porcupine.� Grizzly bear, native to the western slope became extinct
in 1924.� Birds include eagles, hawks, owls, woodpeckers, falcons,
osprey, stellar jay, herons, quail, kingfisher, goshawk and blue grouse.�
Species of concern include the California spotted owl.� Introduced
species include turkey and beaver.
Elevation.� 1,000 to 14,495 feet.� Local relief ranges
from 500 to 2000 feet.
Precipitation.� 10 to 90 inches during fall, winter and
spring.� Occurs mostly as snow above 6000 feet.� Rain on snow
is common.� Summers are commonly dry with low humidity.
Temperature.� 25� to 60�F.
Growing Season.� 10 to 200 days.
Surface Water Characteristics.� Many rapid flowing rivers
and streams.� Rivers flow west from the crest in deeply incised canyons
with bedrock controlled channels to the Great Valley section and Pacific
Ocean.� Rivers flow east from the crest in mostly bedrock controlled
channels terminating in basins in the Mojave Desert, Mono or Northwestern
Basin and Range sections.� There are numerous lakes and wet meadows
associated with glaciated areas above 5,000 feet.
Disturbance Regimes.
Fire: At lower and mid-elevations, historic occurrence has changed
from frequent, low intensity ground fires to infrequent, high intensity
stand replacing fires.� At higher elevations, historic occurrence
has changed from infrequent, low and moderate intensity ground fires to
infrequent, low, moderate and high intensity surface or stand replacing
fires.
Seismic Activity: Seismically active areas along eastern boundary
with strong shaking and ground rupture.
Climate: Wide fluctuations in precipitation and temperature
for periods of years result in significant or catastrophic changes in biological
communities.� Snow avalanches are common at higher elevations.
Land Use. Composition and successional sequence of some communities
has changed because of plant and animal species introduced between the
mid 1800�s and early 1900�s related to mining, grazing, forestry and recreational
activities.� Expanding urban uses occur scattered throughout foothills
and some high elevation areas.� Water diversions for hydroelectric
power, agriculture, and municipal and domestic use are common within and
between river systems.
Cultural Ecology.� Humans have been utilizing the Sierra
Nevada for about 10,000 years, and have been an integral part of its ecology
for 3,000 to 5,000 years, particularly with documented use of fire to facilitate
gathering and to generate species preferred for foodstuffs, basketry materials,
and other needs.� Extensive procurement and processing of lithic,
acorn, pine nut, basketry fiber, and other resources resulted in innumerable
areas of lithic quarry, bedrock mortar, pinyon, Jeffrey pine, sugar pine,
oak grove, and other resource alteration.� Contemporary attitudes
and beliefs are dichotomized between emphasis on amenity/newcomer and commodity/long-time
resident values.� Human environment is characterized by a rural lifestyle
of open space and outdoor leisure activity.� Recreation is the primary
economic emphasis, trailed by government employment, lumbering, mining,
and grazing.� The Sierra is experiencing rapid retiree and commuter
resident growth, and large transient recreation populations that provide
constant resource pressures.
Subsections.� The Sierra Nevada Section is divided into
21 subsections.
To
obtain information about a particular subsection, click the subsection.
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