Great Basin Desert
Central Basin and Range Great Basin shrub steppe | |
---|---|
cold semi-arid (BSk) | |
Conservation | |
Habitat loss | 90%[3] |
Protected | 76.62%[2] |
The Great Basin Desert is part of the
The ecology of the desert varies across geography also. The desert's high elevation and location between mountain ranges influences regional climate: the desert formed by the rain shadow of the Sierra Nevada that blocks moisture from the Pacific Ocean, while the Rocky Mountains create a barrier effect that restricts moisture from the Gulf of Mexico.[9] Different locations in the desert have different amounts of precipitation depending on the strength of these rain shadows. The environment is influenced by Pleistocene lakes that dried after the last ice age: Lake Lahontan and Lake Bonneville. Each of these lakes left different amounts of salinity and alkalinity.
Definition and boundaries
The Great Basin Desert is defined by its animals and plants,[4] yet the boundaries are unclear.[11]
Scientists have different definitions of the Great Basin Desert, which are often defined by negatives. J. Robert Macey defines the "Great Basin scrub desert as lacking
The study and definition of ecoregions can also indicate the boundaries of the Great Basin Desert. In 1987 J.M. Omernik defined a desert ecoregion between the Sierra Nevada and Wasatch Range, naming it the "Northern Basin and Range" ecoregion.[13] In 1999, the U.S. EPA renamed the "Northern Basin and Range" the "Central Basin and Range" and the "(Snake River) High Desert" the "Northern Basin and Range".[14][a] The World Wildlife Fund adopted the Basin and Range ecoregions from Omernik,[15] but excised a small region of high-altitude areas which contain Holocene refugia,[16] from the former "Northern Basin and Range" ecoregion and renamed it the "Great Basin Shrub Steppe".[3][15] Although the EPA had refined the boundaries of the Central Basin and Range ecoregion by 2003,[14][b] when USGS geographer Christopher Soulard wrote his reports on the region, his maps used the 1999 boundary for the "Central Basin and Range",[1] which is essentially the same as the "Great Basin Shrub Steppe".[c] He states that the Great Basin Desert is "encompassed within" that area.[1]
This article describes the general ecology of the region, including the high-elevation areas, and does not rely on minor differences in the definitions of the ecoregion or desert. See Great Basin montane forests for more specific details on the high-elevation ecoregion.
Climate
The climate of the Great Basin desert is characterized by extremes: hot, dry summers and cold, snowy winters; frigid alpine ridges and warm, windy valleys; days over 90 °F (32 °C) followed by nights near 40 °F (4 °C). This is the climate of the high desert.[18]
The Great Basin desert climate begins with the Sierra Nevada in
On any given day, the weather across the Great Basin desert is variable. The region is extremely mountainous, and the temperatures vary depending on the elevation. In general, temperature
This dry climate and rugged topography proves too harsh for many plant and animal species; however, genetic adaptations to these conditions have led to reasonably high species richness within the ecoregion.[7]
The Great Basin National Park, located in a central part of the Great Basin desert, provides perhaps the best example of a typical climate for the region.
Climate data for Great Basin National Park - Lehman Caves Visitor Center (elevation 6,840 feet (2,080 m)) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
Record high °F (°C) | 67 (19) |
66 (19) |
74 (23) |
81 (27) |
91 (33) |
97 (36) |
100 (38) |
96 (36) |
93 (34) |
83 (28) |
77 (25) |
67 (19) |
100 (38) |
Mean daily maximum °F (°C) | 40.5 (4.7) |
42.8 (6.0) |
48.7 (9.3) |
56.7 (13.7) |
66.5 (19.2) |
77.4 (25.2) |
85.7 (29.8) |
83.3 (28.5) |
74.5 (23.6) |
61.7 (16.5) |
48.4 (9.1) |
41.1 (5.1) |
60.6 (15.9) |
Mean daily minimum °F (°C) | 18.9 (−7.3) |
21.2 (−6.0) |
25.5 (−3.6) |
31.5 (−0.3) |
40.0 (4.4) |
49.0 (9.4) |
57.4 (14.1) |
55.8 (13.2) |
47.0 (8.3) |
37.1 (2.8) |
25.9 (−3.4) |
19.6 (−6.9) |
35.7 (2.1) |
Record low °F (°C) | −20 (−29) |
−15 (−26) |
−2 (−19) |
0 (−18) |
6 (−14) |
14 (−10) |
32 (0) |
32 (0) |
10 (−12) |
6 (−14) |
−12 (−24) |
−19 (−28) |
−20 (−29) |
Average precipitation inches (mm) | 1.05 (27) |
1.18 (30) |
1.37 (35) |
1.21 (31) |
1.24 (31) |
0.87 (22) |
0.97 (25) |
1.18 (30) |
1.08 (27) |
1.24 (31) |
0.97 (25) |
0.96 (24) |
13.33 (339) |
Average snowfall inches (cm) | 12.8 (33) |
13.8 (35) |
13.2 (34) |
7.1 (18) |
2.1 (5.3) |
0.2 (0.51) |
0 (0) |
0 (0) |
0.2 (0.51) |
3.7 (9.4) |
8.7 (22) |
10.7 (27) |
72.6 (184) |
[citation needed] |
Climate data for Fallon, Nevada. (Elevation 3,960 feet (1,210 m)) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
Record high °F (°C) | 71 (22) |
78 (26) |
84 (29) |
90 (32) |
102 (39) |
106 (41) |
108 (42) |
105 (41) |
100 (38) |
92 (33) |
81 (27) |
72 (22) |
108 (42) |
Mean daily maximum °F (°C) | 44.3 (6.8) |
51.3 (10.7) |
58.9 (14.9) |
65.9 (18.8) |
73.9 (23.3) |
83.1 (28.4) |
92.2 (33.4) |
90.1 (32.3) |
81.1 (27.3) |
69.2 (20.7) |
55.4 (13.0) |
45.4 (7.4) |
67.6 (19.8) |
Mean daily minimum °F (°C) | 18.1 (−7.7) |
23.2 (−4.9) |
27.8 (−2.3) |
33.9 (1.1) |
41.4 (5.2) |
47.9 (8.8) |
54.0 (12.2) |
51.4 (10.8) |
43.2 (6.2) |
33.8 (1.0) |
24.8 (−4.0) |
18.9 (−7.3) |
34.9 (1.6) |
Record low °F (°C) | −25 (−32) |
−27 (−33) |
1 (−17) |
13 (−11) |
20 (−7) |
27 (−3) |
35 (2) |
33 (1) |
21 (−6) |
12 (−11) |
0 (−18) |
−21 (−29) |
−27 (−33) |
Average precipitation inches (mm) | 0.54 (14) |
0.54 (14) |
0.46 (12) |
0.51 (13) |
0.60 (15) |
0.43 (11) |
0.16 (4.1) |
0.22 (5.6) |
0.28 (7.1) |
0.41 (10) |
0.38 (9.7) |
0.48 (12) |
4.98 (126) |
Average snowfall inches (cm) | 1.8 (4.6) |
0.9 (2.3) |
0.8 (2.0) |
0.2 (0.51) |
0.1 (0.25) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0.1 (0.25) |
0.5 (1.3) |
1.3 (3.3) |
5.7 (14) |
Source: The Western Regional Climate Center[19] |
The
Climate data for Knolls, Great Salt Lake Desert, Utah. (Elevation 4,250 feet (1,300 m)) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
Record high °F (°C) | 63 (17) |
63 (17) |
79 (26) |
87 (31) |
98 (37) |
104 (40) |
106 (41) |
103 (39) |
99 (37) |
89 (32) |
71 (22) |
66 (19) |
106 (41) |
Mean daily maximum °F (°C) | 36.5 (2.5) |
41.4 (5.2) |
54.4 (12.4) |
62.3 (16.8) |
72.3 (22.4) |
83.5 (28.6) |
92.8 (33.8) |
90.9 (32.7) |
80.0 (26.7) |
64.3 (17.9) |
46.5 (8.1) |
36.5 (2.5) |
63.4 (17.4) |
Mean daily minimum °F (°C) | 16.9 (−8.4) |
19.3 (−7.1) |
29.1 (−1.6) |
36.6 (2.6) |
44.9 (7.2) |
54.7 (12.6) |
62.1 (16.7) |
59.5 (15.3) |
48.0 (8.9) |
34.4 (1.3) |
23.3 (−4.8) |
14.5 (−9.7) |
37.0 (2.8) |
Record low °F (°C) | −16 (−27) |
−17 (−27) |
−1 (−18) |
14 (−10) |
24 (−4) |
35 (2) |
43 (6) |
39 (4) |
25 (−4) |
8 (−13) |
−3 (−19) |
−25 (−32) |
−25 (−32) |
Average precipitation inches (mm) | 0.61 (15) |
0.46 (12) |
0.91 (23) |
1.01 (26) |
1.23 (31) |
0.68 (17) |
0.36 (9.1) |
0.31 (7.9) |
0.56 (14) |
0.77 (20) |
0.61 (15) |
0.38 (9.7) |
7.88 (200) |
Average snowfall inches (cm) | 0.3 (0.76) |
0.1 (0.25) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0.1 (0.25) |
0.5 (1.3) |
Source: The Western Regional Climate Center[20] |
Biological communities
The pattern of 'basin and range' with adjacent basins and ranges in this region results in incredible biological diversity. Climate, elevation, soil type, and many anthropogenic variables greatly influence the diversity and distribution of shrubland, grassland, and woodland communities in the desert. Across the high desert there are numerous sub-climates correlating to the varied elevations. Heading from the valley bottoms to the mountain peaks one will encounter constantly changing combinations of plant and animal species making up some 200 distinct biological communities. These communities can be generally grouped into six general communities or "life zones".[21]
Shadscale zone
In the lower valley bottoms where mountain run off evaporates to create saline soils is the
Sagebrush zone
The drop in soil salinity and increase in moisture as elevation increases leads to a transition to sagebrush (
Pinyon-Juniper community
The
The elevational range of this zone varies, but it is usually found between 6,000 and 8,000 feet (1,800 and 2,400 m), with lower limits determined by lack of moisture and the upper limits determined by temperature. The pinyon-juniper community consists of short evergreen trees that rarely grow over 20 feet in height.[21] This zone of dense vegetation, made possible by thermal inversions and increased precipitation, is important to a wide variety of isolated animals that rely on this vegetation interface for survival (for example, Eutamias palmeri).[7][11]
The trees are widely spaced and have an understory of a mixture of shrubs and herbaceous plants, often with nearly bare ground. These characteristics have led this zone to be named the "pygmy forest" by many scientists. The lower end of this zone is dominated by juniper; the middle is a combination of both species, and the upper end is dominated by pinyon.[21]
Montane community
The taller ranges of the Great Basin desert have a montane community. Due to the great distances created by basins between these small forest habitats, various rock substrates, and local climates, montane forests are tremendously varied across the desert.[21]
Isolated from one mountain range to the next, montane communities in the region have long individual histories, each one affected differently by chance factors of migration over vast expanses of desert. Smaller communities are also vulnerable to adverse effects of climate change and to genetic drift.[21]
The bristlecone pine is an important species that is indicative of the Great Basin desert. Bristlecones live a long time, some for thousands of years. The harsh areas they occupy are often devoid of other plant life, so there is little competition and reduced risk of fire. The trees grow very slowly, producing very dense, disease-resistant wood. These factors contribute to the bristlecone's long life.[21]
Alpine community
Some mountain ranges in the Great Basin desert are high enough to have an
Riparian community
The
Subregions
The U.S.
Salt deserts
The Salt desert ecoregion is composed of nearly level
Shadscale-dominated saline basins
The Shadscale-dominated saline basins ecoregion is arid, internally drained and gently sloping to nearly flat. These basins are in, or are characteristic of, the
Lahontan and Tonopah playas
The nearly level and often barren Lahontan and Tonopah playas contain
Lahontan salt shrub basin
The Lahontan salt shrub basin is an expansive dry plain that was once below Pleistocene Lake Lahontan. The
Lahontan sagebrush slopes
Hills,
Lahontan uplands
The Lahontan uplands are restricted to the highest elevations of the mountains ranges within the Lahontan salt shrub basin. Slopes vary in elevation from 6,400 to 8,800 feet (2,000 to 2,700 m) and are covered in sagebrush, grasses, and scattered
Upper Humboldt Plain
The Upper Humboldt Plains ecoregion is an area of rolling plains punctuated by occasional
Carbonate Sagebrush Valleys
The basins and semi-arid uplands of the Carbonate Sagebrush Valleys surround the carbonate ranges of eastern Nevada. These valleys are underlain by
Central Nevada high valleys
The Central Nevada high valleys ecoregion contains sagebrush-covered rolling valleys that are generally over 5,000 feet (1,500 m) in elevation.
Central Nevada mid-slope woodland and brushland
The Central Nevada mid-slope woodland and brushland ecoregion at 6,500 to 8,000 feet (2,000 to 2,400 m) of elevation is analogous in altitudinal range to other woodland areas in Nevada. However, continuous woodland is not as prevalent on the mountains of central Nevada as in other woodland ecoregions, such as ecoregions 13d and 13q. Pinyon-
Central Nevada Bald Mountains
The Central Nevada Bald Mountains are dry and mostly treeless. Although they rise only 100 miles (160 km) east of the
Tonopah Basin
The Tonopah Basin lies in the transition between the Great Basin Desert and the more southerly
Endangered species
The topography of the Great Basin desert ("island" mountain tops separated from one another by vast expanses of desert valleys) renders it vulnerable to extinctions. Populations that occupy the high peaks are isolated from one another; therefore, they cannot interbreed. Small populations are more vulnerable to the forces of extinction - generally small populations have less genetic diversity and therefore a lesser ability to adapt to changing conditions. Groundwater pumping, road and home construction, grazing, and mining are all activities that alter habitat; as more habitat is affected, the threat of extinction increases. The Great Basin desert is home to many threatened and endangered species:[21]
- Birds
- Least tern (Sterna antillarum athalassos)
- Plants
- Sodaville milkvetch (Astragalas lentiginosus var. sesquimetralis)
- Ute lady's tresses (Spiranthes diluvialis)
- Fish
- Lahontan cutthroat trout (Oncorhynchus clarki henshawi)
- Desert dace (Eremichthys acros)
- White River spinedace (Lepidomeda albivallis)[26]
- Mammals
- Utah prairie dog (Cynomys parvidens)[27]
See also
- Becky Peak Wilderness (BLM)
- Bristlecone Wilderness (BLM)
- Goshute Canyon Wilderness (BLM)
- Government Peak Wilderness (BLM)
- Great Basin
- Great Basin National Park
- Highland Ridge Wilderness (BLM)
- Humboldt-Toiyabe National Forest
- Bald Mountain Wilderness (Humboldt NF)
- Currant Mountain Wilderness (Humboldt NF)
- East Humboldt Wilderness (Humboldt NF)
- High Schells Wilderness (Humboldt NF)
- Jarbidge Wilderness (Humboldt NF)
- Quinn Canyon Wilderness (Humboldt NF)
- Red Mountain Wilderness (Humboldt NF)
- Shellback Wilderness (Humboldt NF)
- White Pine Range Wilderness (Humboldt NF)
- Mount Grafton Wilderness (BLM)
- Mount Moriah Wilderness (Humboldt NF / BLM)
- South Egan Range Wilderness (BLM)
- Fish Springs National Wildlife Refuge
- Ruby Lake National Wildlife Refuge
- Fallon National Wildlife Refuge
- Stillwater National Wildlife Refuge
Notes
- ^ The map on this website illustrates the boundaries of the "(Snake River) High Desert", which had been split off earlier from Ormernik's "Snake River Basin/High Desert".[14]
- ^ The Northern Basin and Range ecoregion was extended further east, contracting the eastern portion of the Central Basin and Range to the south, separating it from the Snake River Plain ecoregion.[17]
- ^ Both areas correspond to Omernik's Northern Basin and Range ecoregion.
References
- ^ a b c Soulard, Christopher E. (2012). "20. Central Basin and Range Ecoregion" (PDF). In Sleeter, Benjamin M.; Wilson, Tamara S.; Acevedo, William (eds.). Status and Trends of Land Change in the Western United States—1973 to 2000. U.S. Geological Survey. Professional Paper 1794–A.
- ^ a b c
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. ISBN 978-0-520-26256-0.
- ^ a b c "Great Basin shrub steppe". Terrestrial Ecoregions. World Wildlife Fund.
- ^ a b "What is the Great Basin?". National Park Service. Retrieved 2015-07-14.
- ^ "Deserts - Great Basin National Park (U.S. National Park Service)".
- ^ OCLC 668191550.
- ^ a b c d e f g h This article incorporates public domain material from Christopher E. Soulard. Land-Cover Trends of the Central Basin and Range Ecoregion (PDF). United States Geological Survey.
- .
- OCLC 8388381.
- ^ a b Level III and IV Ecoregions of the Continental United States, EPA, archived from the original on 2016-01-23
- ^ a b c d e f g Brussard, P.F.; Charlet, D.A.; Dobkin, D.S.; Ball, L.C. (1998). "Great Basin-Mojave Desert Region" (PDF). In Mac, M.J.; Opler, P.A.; Puckett Haeker, C.E.; et al. (eds.). Status and trends of the nation's biological resources. Vol. 2. Reno, Nevada: U.S. Geological Survey. Archived from the original (PDF) on 2007-07-14.
- ^ a b Macey, J. Robert (May 28, 1986). The Biogeography of a Herpetofaunal Transition Between the Great Basin and Mojave Deserts (PDF) (Report). Retrieved 2011-11-22.
Banta & Tanner (1964) felt that the Great Basin Desert [sic] deserved recognition…and defined it…as the interior drainage lying between the Sierra Nevada and the Wasatch Mountains of Utah. For the purpose of this study I am defining the Great Basin Desert as the high elevation desert that lacks Creosote Bush.
- ^ Omernik, James M. (1995). "Ecoregions: a framework for managing ecosystems" (PDF). The George Wright Forum. 12 (1): 35–51.
- ^ a b c "Ecoregional Boundaries; Omernik Ecoregions Level 3, Metadata". NV Geospatial Data Browser. EPA. 2003. Archived from the original on 2014-01-12.
- ^ ISBN 978-0-520-26747-3.
- ^ a b "Great Basin montane forests". Terrestrial Ecoregions. World Wildlife Fund.
- ^ "Level III Ecoregions of the Continental United States (revised 2003)" (PDF).
- ^ a b c This article incorporates public domain material from Climate: Past & Present (PDF). National Park Service. Retrieved 2015-07-20.
- ^ "Seasonal Temperature and Precipitation Information". Western Regional Climate Center. Retrieved April 1, 2013.
- ^ "Seasonal Temperature and Precipitation Information". Western Regional Climate Center. Retrieved August 28, 2013.
- ^ a b c d e f g h i j k l m This article incorporates public domain material from Ecology of the Great Basin (PDF). National Park Service. Retrieved 2015-07-13.
- OCLC 43401391.
- .
- OCLC 32333902. Biological Report 28.
- ^ a b c d e f g h i j k l This article incorporates public domain material from Level IV Ecoregions of Nevada--poster front side (PDF). United States Geological Survey. Retrieved 2015-07-18.
- ^ "White River Spinedace (Lepidomeda albivallis)". Nevada Fish & Wildlife Office. U.S. Fish & Wildlife Service.
- ^ "Utah prairie dog (Cynomys parvidens)". Nevada Fish & Wildlife Office. U.S. Fish & Wildlife Service. [permanent dead link]
Further reading
- Trimble, Stephen (1999). The Sagebrush Ocean: A Natural History Of The Great Basin. Reno: University of Nevada Press. ISBN 0874173434.
External links
- Media related to Great Basin Desert at Wikimedia Commons