Ecology of the Rocky Mountains
Encyclopedia
The ecology of the Rocky Mountains is diverse, due to the effects of a variety of environmental factors. The Rocky Mountains
are the major mountain range in western North America
, running from the far north of British Columbia
in Canada
to New Mexico
in the southwestern United States
, climbing from the Great Plains
at or below 1800 feet (548.6 m) to peaks of over 14000 feet (4,267.2 m). Temperature and rainfall varies greatly also and thus the Rockies are home to a mixture of habitats including the alpine
, subalpine
and boreal
habitats of the Northern Rocky Mountains
in British Columbia and Alberta
, the coniferous forests of Montana
and Idaho
, the wetland
s and prairie
where the Rockies meet the plains, a different mix of conifers on the Yellowstone Plateau
in Wyoming
and in the high Rockies of Colorado
and New Mexico
, and finally the alpine tundra of the highest elevations.
These habitats are home to a great deal of wildife from large grazing mammals such as the large herds of elk
, moose
and mule
, smaller mountain goat
s and bighorn sheep
, predators like black bear
, grizzly bear
, wolves, and coyote
along with a great variety of small mammals, fish, reptiles and amphibians, hundreds of bird species, and tens of thousands of species of terrestrial and aquatic invertebrates and soil organisms.
Permanent human settlement of the Rocky Mountains has caused numerous species to go into decline, including species of trout, birds, and sheep. Gray wolves
and grizzly bears have been completely eliminated from the United States portion of the range, but are returning due to conservation measures.
range in latitude between the Liard River
in British Columbia (at 59° N) and the Rio Grande
in New Mexico (at 35° N), and in height up to the highest peak, Mount Elbert
at 14440 feet (4,401.3 m), taking in great valleys such as the Rocky Mountain Trench
. Precipitation ranges from 10 inches (254 mm) per year in the southern valleys to 60 inches (1,524 mm) per year locally in the northern peaks. Average January temperatures can range from 20 °F (-6.7 °C) in Prince George, British Columbia
to 43 °F (6.1 °C) in Trinidad, Colorado
.
. Areas of the Rockies that do not support or have few trees include the prairie of the eastern foothills and the Alpine tundra. The foothill prairie grassland lies to the east of the Rockies where the mountains fall to meet the Great Plains
at the Rocky Mountain Front
(below roughly 1800 feet (548.6 m)). Alpine tundra meanwhile occurs in regions above the treeline, which varies from 12000 feet (3,657.6 m) in New Mexico to 2500 feet (762 m) at the northern end (near the Yukon).
The USGS defines ten forested zones in the Rocky Mountains. The more southern, warmer, drier zones are defined by the presence of pinyon pine
s/juniper
s, ponderosa pine
s, or oak
s mixed with pine
s. The more northern, colder, wetter zones are defined by Douglas-fir
s, Cascadian
species (such as western hemlock
), lodgepole pine
s/quaking aspens, or fir
s mixed with spruce
. Near the treeline, zones can consist of white pines (such as whitebark pine
or bristlecone pine
); or a mixture of white pine, fir, and spruce that appear as shrub-like krummholz
. Finally, rivers and canyons are home to unique forest habitats even in the more arid parts of the mountain range.
Biotic zones and vegetation types in the Rocky Mountains can be explained by elevation
, aspect
, and precipitation
. Merriam
recognized that two-dimensional diagrams of elevation and aspect described plant community distribution in the southern Rocky Mountains. Other ecologists generally embraced this two-dimensional view until the complexities of environmental gradients such as temperature
, precipitation, solar radiation, wind
, soil
s, and hydrology
could be described and modeled. Peet provided the most complete description of 10 major forest community types, which are summarized here. Two nonforested vegetation types, plains and alpine tundra, described by Sims and Billings, are added. Because of the variations in latitude and precipitation along this huge mountain range, the elevations presented here are gross generalizations.
Extensive investigations have been made of the forests of the Rocky Mountains. Weber cautioned that the vegetation zones "overlap and telescope into each other considerably" in a landscape that is "always full of surprises." The resulting patchwork mosaic of vegetation types and disturbance regimes leads to a complex of side-by-side communities, wildlife habitats, and species distributions.
to the north and by short-grass prairie to the south. The prairie, some of which has been described as the Montana Valley and Foothill grasslands
generally extends to elevations of 1800 metres (5,905.5 ft). Dominant plants of the mixed grass prairie include little bluestem
, needlegrass
es, wheatgrass
es, sand-reeds, and gramas
, with dropseeds and cottonwoods in riparian zones. Short-grass prairie species include little bluestem, buffalo grass
, western wheatgrass
, sand dropseed, ringgrass, needle-and-thread, Junegrass, and galleta. Extensions of these vegetation types reach well into the Rocky Mountains along the valleys and on dry slopes. Plant species composition varies locally with changes in soil characteristics and topographic position—that is, from hilltops to valley bottoms.
s, and willow
s line streamsides and canyons. The herbaceous layer in riparian communities is often more diverse than upslope areas and adjacent forests. Riparian and canyon vegetation types are generally too thin or too small to be displayed on regional vegetation maps, but the habitat is extremely important in the arid West.
s. Mexican pinyon
s and singleleaf pinyons are found in western Utah, alligator junipers
and Rocky Mountain junipers grow to the south, and Utah junipers grow to the north. Many shrubs and grasses of the plains occupy the gaps between tree outcrops. Heavy livestock grazing is associated with the spread of junipers (by reducing competition from grasses), and fire suppression is partly responsible for their continued dominance.
woodlands varies from scattered individuals in low-elevation or rocky areas to dense forests at higher elevations or on deeper soils. Although ponderosa pines dominate the biomass of this community, other tree species such as Douglas-fir
and Rocky Mountain juniper, shrubs (for example, raspberries
, big sagebrush, gooseberries, currants
, bitterbrush), and herb layers (such as mountain muhly
, sedges
, and sagebrush
es) can develop. Typical intervals between natural fires are less than 40 years in most ponderosa pine forests.
In geological time, ponderosa pine ecosystems are relatively new to the foothills of the central Rocky Mountains. An even newer addition to the ecosystem, European-American settlers, devastated the ponderosa pine forests through logging for houses, fencing, firewood, mine timbers, and railroad ties, and with fire. The ponderosa pine forests were close to the developing population centers at the forest-prairie edge. The scale of the loss of ponderosa pine habitat is demonstrated best in several hundred paired photographs from the early 20th century and 1980s. However, nearly all the paired photographs also reveal that the most important feature of the ponderosa pine ecosystem is its resilience. Ponderosa pine seedlings establish quickly in disturbed sites. Research in the Front Range of Colorado shows a tenfold increase in ponderosa pine biomass since 1890 in many stands. This regeneration has restored habitat for many wildlife species.
s, other oak species (for example, Emory oak
s, silverleaf oaks, netleaf oaks), and shrubs (such as sumac
s, buckbrushes
, and mountain-mahoganies). In the absence of fire, the oak stands may be invaded by pines.
, or lodgepole pine
. Like ponderosa pine, Douglas-fir is tolerant of frequent, low-intensity surface fires. Fire intervals in Douglas-fir forests in Wyoming average 50–100 years.
, western redcedar, grand fir
, mountain hemlock
, and larch
es. These forests are subject to infrequent, high-intensity fires.
and balsam poplar
. In the northern Canadian Rockies, black spruce
also occurs in this biotic zone.
Intervals between fires typically range from 100 to 300 years. As evidenced by the fires in the Yellowstone National Park in 1988
, lodgepole pine forests are rejuvenated by crown fires that replace tree stands. Although aspen stands generally cover less than 1% of the landscape (for example, Rocky Mountain National Park, Grand Teton National Park), they are keystone communities
for hundreds of birds and mammals and are especially important forage for deer and elk.
s and fir
s and are floristically and structurally similar to the boreal conifer forests to the north. Dominant tree species in the Colorado Rocky Mountains subalpine forests include Engelmann spruce
and subalpine fir
. In the Black Hills of South Dakota, white spruce
replaces Engelmann spruce. Further north are the lodgepole pine
, Engelmann spruce, and alpine fir mix of the Alberta Mountain forests
above 1675 metres (5,495.4 ft) of elevation. Stand-replacing fires typically occur at 200- to 400-year intervals. Widespread insect outbreaks in spruce-fir forests occur more frequently.
in the northern Rocky Mountains, limber pine
in the central and north-central Rocky Mountains, and bristlecone pine
in the southern Rocky Mountains. Typical intervals between fires range from 50 to 300 years. The white pines are tolerant of extreme environmental conditions and can be important postfire successional species. The whitebark pine is a keystone species
in upper subalpine forests of the northern Rocky Mountains. However, the whitebark pine has been in decline due to White Pine Blister Rust: whitebark pine mortality in some areas exceeds 90%. Entire forest vistas, like that at Avalanche Ridge near Yellowstone National Park’s east gate, are expanses of dead, gray whitebarks.
. Krummholz islands may actually move about 2 centimeters per year in response to the wind; they reproduce by vegetative layering on their lee sides, while dying back from wind damage on their windward sides. Under favorable climatic conditions, krummholz can assume an upright treelike form or can increase their cone crops and seedling establishment.
is a complex of high-elevation meadow
s, fell (barren) field
s, and talus
(rock) slopes above treeline. Depending on latitude, treeline occurs between 3400 and 4000 m (11,154.9 and 13,123.4 ft) in the United States, and 2200 and 2450 m (7,217.8 and 8,038.1 ft) in Canada. Grasses and sedges dominate the meadow communities, and fe
ns (a type of wet meadow) and willows exist in wet soils. Vegetation in the alpine zone is similar to that in the Arctic: 47% of the plant species in the alpine zone of the Beartooth Mountains in Wyoming and Montana are also found in the Arctic. This high-diversity area includes alpine sagebrush, tufted hairgrass, clover
s, pussytoes, and succulents, and hundreds of grasses and wildflower species.
, moose
, mule
and white-tailed deer
, pronghorns, mountain goat
s, bighorn sheep
, black bears
, grizzly bear
s, wolves, coyote
s, lynx
es, and wolverine
s. For example, North America's largest herds of moose is in the Alberta-British Columbia foothills forests
. The status of most species in the Rocky Mountains is unknown however, due to incomplete information. Even basic regional information is not available on many nocturnal species (for example, bat
s, raccoon
s, and so forth); invertebrate
s; lichen
s, moss
es, and fungi; and soil microorganisms.
European-American settlement of the mountains has adversely impacted native species. Examples of some species that are known to have declined include western toad
s, greenback cutthroat trout
s, white sturgeon
s, white-tailed ptarmigan
s, trumpeter swan
s, and bighorn sheep
. In the United States portion of the mountain range, apex predator
s such as grizzly bear
s and gray wolves had been extirpated from their original ranges, but have partially recovered due to conservation measures and reintroduction. Other recovering species include the bald eagle
and the peregrine falcon
. Species such as the black bear and mountain
lion, many small mammals, and common bird and plant species are described as stable because, in most instances, the populations are persistent and not rapidly increasing or declining.
s and butterflies. Most of the Rocky Mountain states and the Front Range of Colorado
in particular support high species richness of butterflies and moths. In Colorado, the diverse habitats—from prairie to tundra—support about 2,000 species of butterflies, moths, and skipper
s; more than 1,000 species are in the Front Range. Some species of grasshopper
s are unique to individual mountaintops in Colorado, New Mexico, Arizona, Nevada, and Utah. The Rocky Mountain locust
, a common pest to farmers in the 19th century, is now extinct. Heavy grazing along river valleys in Montana and Idaho is thought to have irreparably destroyed locust breeding areas.
, increased ultraviolet
radiation, and disease. The widespread declines of amphibian populations throughout the Rocky Mountains mirror these global trends. Western toad
s, once common between altitudes of 2300 and 4200 m (7,545.9 and 13,779.5 ft) throughout the central and northern Rocky Mountains, now occupy less than 20% of their previous range, from southern Wyoming to northern New Mexico. Eleven populations of western toads disappeared from the West Elk Mountains
of Colorado between 1974 and 1982 because of a bacterial infection and, perhaps, multiple sublethal environmental causes. In the past two decades, western toads disappeared from 83% of their historical range in Colorado and from 94% of Wyoming sites. Populations of northern leopard frog
s are significantly declining throughout the Rocky Mountains.
Greenback cutthroat trout
historically inhabited the cold-water streams in the mountains of Colorado. The species was near extinction by the early 20th century because of broad-scale stocking of these streams with nonindigenous brown trout from Europe and rainbow trout from the Pacific Coast, and because of land and water exploitation, mining, and logging. Native genetic diversity is now lost in greenback cutthroat trout because this species hybridizes with the introduced fishes. Interagency efforts began in 1959 to save the species. With viable populations now at 48 sites, the greenback cutthroat trout is one of the few species that will be removed from the endangered species list. Three of the four other native subspecies of the cutthroat trout are extinct.
Most aquatic ecosystems in the Rocky Mountains are now influenced by nonindigenous brown trout
and rainbow trout
. One of the more subtle, yet devastating, trends in the Rocky Mountain fishery is loss of genetic diversity in native fishes resulting from introductions of nonindigenous fishes. For example, only 15 of 32 lakes in Glacier National Park, Montana, contain pure genetic strains of the native cutthroat trout. The others contain totally nonindigenous fishes or hybrids with the introduced Yellowstone cutthroat trout or rainbow trout. Introductions of nonindigenous fishes to improve the sport fishery have compromised about 84% of the historical range of the native cutthroat trout.
Yellowstone Lake
in Yellowstone National Park
, Wyoming, is the site of the most recent catastrophic species invasion. The Washington Post reported that the nonindigenous lake trout
, a native of the Great Lakes, had been insidiously introduced into one of the nation's premier fisheries. The native Yellowstone cutthroat trout
may not compete well with lake trout because lake trout eat cutthroat trout. The potential ecological repercussions are staggering. If populations of cutthroat trout decline, grizzly bears could lose an important posthibernation food because the native cutthroat trout spawn in the streams and are easy prey for the bears, whereas the nonindigenous lake trout spawn in deep water.
historically ranged from the mouth of the Columbia River
to the Kootenai River upstream to Kootenai Falls, Montana. The Kootenai River population of the white sturgeon is unstable and declining in size; fewer than 1,000 remain, 80% are older than 20 years, and virtually no recruitment has occurred since 1974, soon after Libby Dam in Montana began regulating flows.
The coniferous and deciduous forests of North America have long been the home of bald eagle
s. Bald eagle populations are now recovering after years of hunting, habitat destruction, and pesticide
-induced deaths. In the early 1970s, Colorado had just one breeding pair of bald eagles but by 1993 biologists counted 19 breeding pairs. In Wyoming nesting attempts increased from 20 in 1978 to 42 in 1988. The bald eagle is not yet fully recovered, however; pesticide residues continue to inhibit bald eagle reproduction, and habitat loss and lead poisoning remain serious threats.
s are cliff-dwelling raptors that once ranged through most of North America. Like the bald eagle, this species was driven to near extinction by pesticides. By 1965 fewer than 20 breeding pairs were known west of the Great Plains
. Even in the Greater Yellowstone ecosystem
, federal spruce budworm
control relied on DDT
, which accumulates in the food chain, causing eggshell thinning and reduced reproductive success in raptors. Six breeding pairs of American peregrine falcons were found in Colorado in the early 1970s. By 1994, 53 pairs were breeding in Colorado. In Wyoming, Montana, and Idaho combined, 8 of 59 historical sites were used by falcons in 1987. Low breeding densities, reproductive isolation, habitat loss, and pesticide poisoning on wintering grounds remain threats to peregrine falcon recovery.
White-tailed ptarmigan
s have been monitored in Rocky Mountain National Park
, Colorado, since 1966. Short-term population cycles are well documented in populations that are not hunted but not in populations outside the park, which are hunted. Although detailed population size data are available from more than 28 years of monitoring, scant information is available on habitat change, predator populations, or other potential causes of change in ptarmigan populations. A 2-year study revealed lower ptarmigan densities where elk use was greater, although characteristics of willow, which is ptarmigan habitat, did not significantly differ in the high- and low-use elk sites. Furthermore, a 2-year study of ptarmigan habitat cannot explain 28-year trends in population size. Habitat loss and other factors partly responsible for ptarmigan deaths—such as predation and competition—were not studied during the 28-year period.
Trumpeter swan
populations were seriously threatened in the 1930s; fewer than 70 birds were thought to exist. Now protected from hunting, more than 1,500 swans winter in the Greater Yellowstone ecosystem, but the size of the breeding population has declined in recent years because of habitat loss.
s breed in the Rocky Mountains and winter in Central and South America. Wildlife biologists suspect that population size declines in the songbirds may be partly the result of increased predation and brood parasitism. Brood parasitism by brown-headed cowbird
s, for example, increases as a result of nearby logging. In conifer forests in west-central Idaho, common songbirds benefited from timber harvest, whereas the abundances declined of rare species that inhabit old-growth forests (hermit thrush, Swainson's thrush, and pileated woodpecker).
Grizzly bear
s once roamed throughout the Rocky Mountains and the western Great Plains. They were hunted relentlessly by European settlers in the 19th century and early 20th century. The last known grizzly bear in Colorado was killed in 1979. The decline of the bears to just 2% of their original range tells of the human-caused extirpation of large predators in the Rocky Mountain region. Only 700-900 grizzly bears may be alive today in the conterminous United States. During the last 20 years, about 88% of all grizzly bears studied in the northern Rocky Mountains were killed by humans.
2005 estimates of wolf populations in the two recovery zones reflect the success the species has had in both areas:
These numbers, added with the estimated number of wolves in northwestern Montana (130), puts the total number of wolves in the Northern Rocky Mountain recovery area at over 1000 individuals. This includes approximately 134 packs (two or more wolves traveling together) and 71 breeding pairs (male and female that successfully rear a litter of at least two until Dec. 31). The recovery goal for the area was 30 breeding pairs total, and this number has been surpassed for some time.
The restoration of the gray wolf to the Yellowstone National Park not only restores an important ecosystem component (the wolf) and process (predation by wolves) to bring the park into better ecological balance, but it also is economically sound. After weighing the costs (including full reimbursement to ranchers for the loss of livestock) and benefits (increased revenues from hunting and tourism), economists estimated (before the actual restoration took place) a net $18 million return during the first year after the wolves were returned, and about $110 million in 20 years. More tourists are expected to visit the area of the Yellowstone National Park and to stay longer in hope of hearing or seeing wolves in the wild. Compensatory payments to ranchers for the loss of cattle and sheep to wolves averaged about $1,800 per year in northwestern Montana.
Population trends in North American elk and deer (mule deer
and white-tailed deer
combined) may be heading in opposite directions. The number of elk has increased steadily in Colorado and Wyoming, whereas the abundances of deer are showing signs of decline. Elk on U.S. Forest Service lands in the Rocky Mountains increased from 268,000 in 1965 to 372,000 in 1984. Similarly, the number of elk on Bureau of Land Management lands rose from 35,000 in 1966 to 114,000 in 1985. Meanwhile, the number of deer on U.S. Forest Service lands declined from 1,742,000 in 1965 to 1,197,000 in 1984. Deer populations also declined on Bureau of Land Management lands. Thus, in some areas in the last 20 years, the abundances of elk have increased by about 40%, whereas deer have decreased by about 30%. Possible reasons for the increase in elk populations include mild winters, range extension into lowlands and highlands, increased adaptability to human-modified landscapes, and lack of predation in spite of increased hunting. The causes of the deer population declines remain unknown but may include excessive harvest in the 1970s and habitat overlap with elk, intensifying competition for similar resources. Note, however, that deer population in the rest of the United States has increased fiftyfold between 1900 and 2005, as hunting has been limited and open space has been preserved.
Pronghorn populations have fluctuated but generally have increased in the past 20 years in Colorado and Wyoming. Moose populations have increased 50% since 1980 in Wyoming and have been rapidly increasing since the introduction into Colorado in 1978 and 1979.
Populations of bighorn sheep
are at only about 2% to 8% of their sizes at the time of European settlement. Causes for the rapid decline from 1870 through 1950 included unregulated harvesting, excessive grazing of livestock on rangeland
s, and diseases transmitted by domestic sheep
. In recent years, 115 translocations were made to restore bighorn sheep into the Rocky Mountains and into many national parks. Only 39% of the 115 bighorn sheep translocations are persisting in 6 Rocky Mountain states. Populations of 100 or more sheep now occur in 10 national park units, populations of 100-200 sheep in 5 units, and populations of more than 500 sheep in 5 units. Populations of fewer than 100 animals exist in 5 other park units.
s once played important roles in shaping vegetation patterns in riparian and meadow communities in the Rocky Mountains. Studies of beaver populations in one small area in Yellowstone National Park (Tower Junction area) in the early 1920s reported 232 beavers and extensive beaver dams. Repeated surveys in the same area in the early 1950s and in 1986 revealed no beavers or dams. Beavers need aspen
s or tall willow
s for food and building materials—resources that are made scarce by lack of both fires and floods and by herbivory by elk, moose, and domestic livestock. Beaver ponds are known to maintain fish and invertebrate populations and to create and maintain riparian zones that are critical to wildlife, yet the beaver is virtually absent in many areas.
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
are the major mountain range in western North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, running from the far north of British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
to New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
in the southwestern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, climbing from the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
at or below 1800 feet (548.6 m) to peaks of over 14000 feet (4,267.2 m). Temperature and rainfall varies greatly also and thus the Rockies are home to a mixture of habitats including the alpine
Alpine
The term alpine refers to the Alps, a European mountain range.Alpine may also refer to:- Geography and geology :* Alpine tundra, the biological community that occurs above the tree line at high altitude...
, subalpine
Subalpine
The subalpine zone is the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.Trees in the...
and boreal
Boreal
Boreal may refer to*Boreal ecosystem**Boreal climate, the climate found in a region of boreal forests, and designated Dfc, Dwc or Dsc in the Köppen climate classification scheme.*boreal forest*Boreal forest of Canada*Boreal Bluet...
habitats of the Northern Rocky Mountains
Northern Rocky Mountains
The Northern Rocky Mountains, usually referred to as the Northern Rockies, are a subdivision of the Canadian Rockies comprising the northern half of the Canadian segment of the Rocky Mountains...
in British Columbia and Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, the coniferous forests of Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
and Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
, the wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
s and prairie
Prairie
Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...
where the Rockies meet the plains, a different mix of conifers on the Yellowstone Plateau
Yellowstone Plateau
The Yellowstone Plateau volcanic field is a geological feature found in the U.S. state of Wyoming. It is a popular site for tourists.The plateau developed through three volcanic cycles spanning two million years that included some of the world's largest known eruptions...
in Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
and in the high Rockies of Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
and New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, and finally the alpine tundra of the highest elevations.
These habitats are home to a great deal of wildife from large grazing mammals such as the large herds of elk
Elk
The Elk is the large deer, also called Cervus canadensis or wapiti, of North America and eastern Asia.Elk may also refer to:Other antlered mammals:...
, moose
Moose
The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...
and mule
Mule Deer
The mule deer is a deer indigenous to western North America. The Mule Deer gets its name from its large mule-like ears. There are believed to be several subspecies, including the black-tailed deer...
, smaller mountain goat
Mountain goat
The Mountain Goat , also known as the Rocky Mountain Goat, is a large-hoofed mammal found only in North America. Despite its vernacular name, it is not a member of Capra, the genus of true goats...
s and bighorn sheep
Bighorn Sheep
The bighorn sheep is a species of sheep in North America named for its large horns. These horns can weigh up to , while the sheep themselves weigh up to . Recent genetic testing indicates that there are three distinct subspecies of Ovis canadensis, one of which is endangered: Ovis canadensis sierrae...
, predators like black bear
American black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...
, grizzly bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...
, wolves, and coyote
Coyote
The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
along with a great variety of small mammals, fish, reptiles and amphibians, hundreds of bird species, and tens of thousands of species of terrestrial and aquatic invertebrates and soil organisms.
Permanent human settlement of the Rocky Mountains has caused numerous species to go into decline, including species of trout, birds, and sheep. Gray wolves
Gray Wolf
The gray wolf , also known as the wolf, is the largest extant wild member of the Canidae family...
and grizzly bears have been completely eliminated from the United States portion of the range, but are returning due to conservation measures.
Setting
The Rocky MountainsRocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
range in latitude between the Liard River
Liard River
The Liard River flows through Yukon, British Columbia and the Northwest Territories, Canada. Rising in the Saint Cyr Range of the Pelly Mountains in southeastern Yukon, it flows southeast through British Columbia, marking the northern end of the Rocky Mountains and then curving northeast back...
in British Columbia (at 59° N) and the Rio Grande
Rio Grande
The Rio Grande is a river that flows from southwestern Colorado in the United States to the Gulf of Mexico. Along the way it forms part of the Mexico – United States border. Its length varies as its course changes...
in New Mexico (at 35° N), and in height up to the highest peak, Mount Elbert
Mount Elbert
Mount Elbert is the highest peak in the Rocky Mountains of North America, at , the highest of the fourteeners in Colorado, and the high point of the Sawatch Range. It is located in Lake County, approximately southwest of Leadville...
at 14440 feet (4,401.3 m), taking in great valleys such as the Rocky Mountain Trench
Rocky Mountain Trench
The Rocky Mountain Trench, or the Trench or The Valley of a Thousand Peaks, is a large valley in the northern part of the Rocky Mountains. It is both visually and cartographically a striking physiographic feature extending approximately from Flathead Lake, Montana, to the Liard River, just south...
. Precipitation ranges from 10 inches (254 mm) per year in the southern valleys to 60 inches (1,524 mm) per year locally in the northern peaks. Average January temperatures can range from 20 °F (-6.7 °C) in Prince George, British Columbia
Prince George, British Columbia
Prince George, with a population of 71,030 , is the largest city in northern British Columbia, Canada, and is known as "BC's Northern Capital"...
to 43 °F (6.1 °C) in Trinidad, Colorado
Trinidad, Colorado
The historic City of Trinidad is a Home Rule Municipality that is the county seat and the most populous city of Las Animas County, Colorado, United States...
.
Biotic zones
Ecologists divide the Rocky Mountain into a number of biotic zones, defined by whether they can support trees, and the presence of one or more indicator speciesIndicator species
An indicator species is any biological species that defines a trait or characteristic of the environment. For example, a species may delineate an ecoregion or indicate an environmental condition such as a disease outbreak, pollution, species competition or climate change...
. Areas of the Rockies that do not support or have few trees include the prairie of the eastern foothills and the Alpine tundra. The foothill prairie grassland lies to the east of the Rockies where the mountains fall to meet the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
at the Rocky Mountain Front
Rocky Mountain Front
The Rocky Mountain Front is an area extending over 100 miles from the central regions of the U.S. state of Montana to southern Alberta, Canada. Here, the Rocky Mountains meet the Great Plains and Canadian Prairie in an abrupt elevation rise of between 4,000 to 5,000 feet...
(below roughly 1800 feet (548.6 m)). Alpine tundra meanwhile occurs in regions above the treeline, which varies from 12000 feet (3,657.6 m) in New Mexico to 2500 feet (762 m) at the northern end (near the Yukon).
The USGS defines ten forested zones in the Rocky Mountains. The more southern, warmer, drier zones are defined by the presence of pinyon pine
Pinyon pine
The pinyon pine group grows in the southwestern United States and in Mexico. The trees yield edible pinyon nuts, which were a staple of the Native Americans, and are still widely eaten...
s/juniper
Juniper
Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...
s, ponderosa pine
Ponderosa Pine
Pinus ponderosa, commonly known as the Ponderosa Pine, Bull Pine, Blackjack Pine, or Western Yellow Pine, is a widespread and variable pine native to western North America. It was first described by David Douglas in 1826, from eastern Washington near present-day Spokane...
s, or oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
s mixed with pine
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
s. The more northern, colder, wetter zones are defined by Douglas-fir
Douglas-fir
Douglas-fir is one of the English common names for evergreen coniferous trees of the genus Pseudotsuga in the family Pinaceae. Other common names include Douglas tree, and Oregon pine. There are five species, two in western North America, one in Mexico, and two in eastern Asia...
s, Cascadian
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...
species (such as western hemlock
Western Hemlock
Tsuga heterophylla. the Western Hemlock, is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Sonoma County, California.-Habitat:...
), lodgepole pine
Lodgepole Pine
Lodgepole Pine, Pinus contorta, also known as Shore Pine, is a common tree in western North America. Like all pines, it is evergreen.-Subspecies:...
s/quaking aspens, or fir
Fir
Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...
s mixed with spruce
Spruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
. Near the treeline, zones can consist of white pines (such as whitebark pine
Whitebark Pine
Pinus albicaulis, known commonly as Whitebark Pine, Pitch Pine, Scrub Pine, and Creeping Pine occurs in the mountains of the Western United States and Canada, specifically the subalpine areas of the Sierra Nevada, the Cascade Range, the Pacific Coast Ranges, and the northern Rocky Mountains –...
or bristlecone pine
Bristlecone pine
The bristlecone pines are a small group of pine trees that are thought to reach an age far greater than that of any other single living organism known, up to nearly 5,000 years....
); or a mixture of white pine, fir, and spruce that appear as shrub-like krummholz
Krummholz
Krummholz or Krumholtz formation — also called Knieholz — is a particular feature of subarctic and subalpine tree line landscapes. Continual exposure to fierce, freezing winds causes vegetation to become stunted and deformed...
. Finally, rivers and canyons are home to unique forest habitats even in the more arid parts of the mountain range.
Biotic zones and vegetation types in the Rocky Mountains can be explained by elevation
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....
, aspect
Aspect (geography)
In physical geography, aspect generally refers to the horizontal direction to which a mountain slope faces. For example, a slope on the eastern edge of the Rockies toward the Great Plains is described as having an easterly aspect...
, and precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
. Merriam
Clinton Hart Merriam
Clinton Hart Merriam was an American zoologist, ornithologist, entomologist and ethnographer.Known as "Hart" to his friends, Dr. Clinton Hart Merriam was born in New York City in 1855. His father, Clinton Levi Merriam, was a U.S. congressman. He studied biology and anatomy at Yale University and...
recognized that two-dimensional diagrams of elevation and aspect described plant community distribution in the southern Rocky Mountains. Other ecologists generally embraced this two-dimensional view until the complexities of environmental gradients such as temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
, precipitation, solar radiation, wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
, soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
s, and hydrology
Hydrology
Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...
could be described and modeled. Peet provided the most complete description of 10 major forest community types, which are summarized here. Two nonforested vegetation types, plains and alpine tundra, described by Sims and Billings, are added. Because of the variations in latitude and precipitation along this huge mountain range, the elevations presented here are gross generalizations.
Extensive investigations have been made of the forests of the Rocky Mountains. Weber cautioned that the vegetation zones "overlap and telescope into each other considerably" in a landscape that is "always full of surprises." The resulting patchwork mosaic of vegetation types and disturbance regimes leads to a complex of side-by-side communities, wildlife habitats, and species distributions.
Plains
The eastern side of the Rocky Mountains is bordered by mixed-grass prairieTallgrass prairie
The tallgrass prairie is an ecosystem native to central North America, with fire as its primary periodic disturbance. In the past, tallgrass prairies covered a large portion of the American Midwest, just east of the Great Plains, and portions of the Canadian Prairies. They flourished in areas with...
to the north and by short-grass prairie to the south. The prairie, some of which has been described as the Montana Valley and Foothill grasslands
Montana Valley and Foothill grasslands
The Montana Valley and Foothill grasslands are an ecoregion of northwestern North America in the northern United States and Canada.-Setting:...
generally extends to elevations of 1800 metres (5,905.5 ft). Dominant plants of the mixed grass prairie include little bluestem
Little bluestem
Schizachyrium scoparium, commonly known as little bluestem or beard grass, is a North American prairie grass. Little bluestem is a perennial bunchgrass and is prominent in tallgrass prairie, along with big bluestem , indiangrass and switchgrass...
, needlegrass
Needlegrass
The term needlegrass may refer to any of several genera of grasses, including:*Achnatherum*Aristida *Nassella*Stipa...
es, wheatgrass
Wheatgrass
Wheatgrass is a food prepared from the cotyledons of the common wheat plant, Triticum aestivum. It is sold either as a juice or powder concentrate. Wheatgrass differs from wheat malt in that it is served freeze-dried or fresh, while wheat malt is convectively dried. Wheatgrass is also allowed to...
es, sand-reeds, and gramas
Bouteloua
Bouteloua is a genus of the grass family, Poaceae. Members of the genus are commonly known as Grama. The genus was named for Claudio and Esteban Boutelou, 19th century Spanish botanists.-Selected species:-External links:*...
, with dropseeds and cottonwoods in riparian zones. Short-grass prairie species include little bluestem, buffalo grass
Buffalo grass
Bouteloua dactyloides, commonly known as Buffalograss or Buffalo Grass, is a prairie grass native to North America. It is a shortgrass found mainly on the high plains and is co-dominant with blue grama over most of the shortgrass prairie.-Description:Buffalograss is a warm-season perennial...
, western wheatgrass
Western Wheatgrass
Pascopyrum is a monotypic genus of grass containing the sole species Pascopyrum smithii, which is known by the common name western wheatgrass. This is a sod-forming rhizomatous perennial grass which is native and common in North America. It grows in grassland and prairie in the Great Plains, where...
, sand dropseed, ringgrass, needle-and-thread, Junegrass, and galleta. Extensions of these vegetation types reach well into the Rocky Mountains along the valleys and on dry slopes. Plant species composition varies locally with changes in soil characteristics and topographic position—that is, from hilltops to valley bottoms.
Riparian and canyon forests
Broad-leaved deciduous cottonwoods, alderAlder
Alder is the common name of a genus of flowering plants belonging to the birch family . The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate Zone and in the Americas along the Andes southwards to...
s, and willow
Willow
Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...
s line streamsides and canyons. The herbaceous layer in riparian communities is often more diverse than upslope areas and adjacent forests. Riparian and canyon vegetation types are generally too thin or too small to be displayed on regional vegetation maps, but the habitat is extremely important in the arid West.
Pinyon-juniper woodland
In the southern Rocky Mountains, a transition occurs between about 1800 and 2500 m (5,905.5 and 8,202.1 ft), where plains communities are accompanied by pinyon pinePinyon pine
The pinyon pine group grows in the southwestern United States and in Mexico. The trees yield edible pinyon nuts, which were a staple of the Native Americans, and are still widely eaten...
s. Mexican pinyon
Mexican Pinyon
The Mexican Pinyon ' is a pine in the pinyon pine group, native to western North America.-Distribution:The range extends from westernmost Texas, United States , south through much of Mexico, occurring widely along the Sierra Madre Oriental and Sierra Madre Occidental ranges, and more rarely in the...
s and singleleaf pinyons are found in western Utah, alligator junipers
Juniperus deppeana
Juniperus deppeana is a small to medium-sized tree reaching 10-15 m tall. It is native to central and northern Mexico and the southwestern United States...
and Rocky Mountain junipers grow to the south, and Utah junipers grow to the north. Many shrubs and grasses of the plains occupy the gaps between tree outcrops. Heavy livestock grazing is associated with the spread of junipers (by reducing competition from grasses), and fire suppression is partly responsible for their continued dominance.
Ponderosa pine woodland
The appearance of ponderosa pinePonderosa Pine
Pinus ponderosa, commonly known as the Ponderosa Pine, Bull Pine, Blackjack Pine, or Western Yellow Pine, is a widespread and variable pine native to western North America. It was first described by David Douglas in 1826, from eastern Washington near present-day Spokane...
woodlands varies from scattered individuals in low-elevation or rocky areas to dense forests at higher elevations or on deeper soils. Although ponderosa pines dominate the biomass of this community, other tree species such as Douglas-fir
Douglas-fir
Douglas-fir is one of the English common names for evergreen coniferous trees of the genus Pseudotsuga in the family Pinaceae. Other common names include Douglas tree, and Oregon pine. There are five species, two in western North America, one in Mexico, and two in eastern Asia...
and Rocky Mountain juniper, shrubs (for example, raspberries
Raspberries
Raspberry may refer to:* Raspberry, various fruit-bearing plants in the genus Rubus, especially two commercially grown species, the red-fruited Rubus idaeus and the black-fruited Rubus occidentalis...
, big sagebrush, gooseberries, currants
Ribes
Ribes is a genus of about 150 species of flowering plants native throughout the temperate regions of the Northern Hemisphere. It is usually treated as the only genus in the family Grossulariaceae. Seven subgenera are recognized....
, bitterbrush), and herb layers (such as mountain muhly
Muhlenbergia montana
Muhlenbergia montana, with the common name Mountain muhly, is a species of grass. It is native to North and Central America, where it is found throughout the Western United States, the Sierra Nevada |Sierra Nevada]], Mexico, and Guatemala....
, sedges
Cyperaceae
Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...
, and sagebrush
Sagebrush
Sagebrush is a common name of a number of shrubby plant species in the genus Artemisia native to western North America;Or, the sagebrush steppe ecoregion, having one or more kinds of sagebrush, bunchgrasses and others;...
es) can develop. Typical intervals between natural fires are less than 40 years in most ponderosa pine forests.
In geological time, ponderosa pine ecosystems are relatively new to the foothills of the central Rocky Mountains. An even newer addition to the ecosystem, European-American settlers, devastated the ponderosa pine forests through logging for houses, fencing, firewood, mine timbers, and railroad ties, and with fire. The ponderosa pine forests were close to the developing population centers at the forest-prairie edge. The scale of the loss of ponderosa pine habitat is demonstrated best in several hundred paired photographs from the early 20th century and 1980s. However, nearly all the paired photographs also reveal that the most important feature of the ponderosa pine ecosystem is its resilience. Ponderosa pine seedlings establish quickly in disturbed sites. Research in the Front Range of Colorado shows a tenfold increase in ponderosa pine biomass since 1890 in many stands. This regeneration has restored habitat for many wildlife species.
Pine-oak woodland
In the southern Rocky Mountains, lower slopes of ponderosa pine communities can be accompanied by Gambel oakGambel oak
Quercus gambelii, or Gambel oak, is a deciduous small tree or large shrub widespread in the foothills and lower mountain elevations of the central southwestern United States and northwestern Mexico: its range is centered on the Colorado Plateau–Four Corners states of Utah-Colorado,...
s, other oak species (for example, Emory oak
Emory oak
Quercus emoryi, the Emory oak, is a species of oak common in Arizona, New Mexico and western Texas , USA, and northern Mexico south to Durango and San Luis Potosí...
s, silverleaf oaks, netleaf oaks), and shrubs (such as sumac
Sumac
Sumac is any one of approximately 250 species of flowering plants in the genus Rhus and related genera, in the family Anacardiaceae. Sumacs grow in subtropical and temperate regions throughout the world, especially in Africa and North America....
s, buckbrushes
Purshia tridentata
Purshia tridentata is a nitrogen fixing shrub in the genus Purshia, native to mountainous areas of western North America ranging from southeastern British Columbia in the north, east to Montana and south to California and New Mexico...
, and mountain-mahoganies). In the absence of fire, the oak stands may be invaded by pines.
Douglas-fir forest
Douglas-firs grow in a broad range from Mexico to British Columbia, generally from near lower treeline upward in elevation to spruce-fir forests. In Colorado, the species ranges from about 1650 to 2700 m (5,413.4 to 8,858.3 ft) and is often found in mixed stands with ponderosa pine, blue spruceBlue Spruce
Picea pungens is a species of spruce native to western North America, from southeast Idaho and southwest Wyoming, south through Utah and Colorado to Arizona and New Mexico. It grows at high altitudes from altitude, though unlike Engelmann Spruce in the same area, it does not reach the alpine...
, or lodgepole pine
Lodgepole Pine
Lodgepole Pine, Pinus contorta, also known as Shore Pine, is a common tree in western North America. Like all pines, it is evergreen.-Subspecies:...
. Like ponderosa pine, Douglas-fir is tolerant of frequent, low-intensity surface fires. Fire intervals in Douglas-fir forests in Wyoming average 50–100 years.
Cascadian forest
Several tree species commonly associated with the Cascade Mountains grow on the rain-swept western slopes of the northern Rocky Mountains. These include western hemlockWestern Hemlock
Tsuga heterophylla. the Western Hemlock, is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Sonoma County, California.-Habitat:...
, western redcedar, grand fir
Grand Fir
Abies grandis is a fir native to the Pacific Northwest and Northern California of North America, occurring at altitudes of sea level to 1,800 m...
, mountain hemlock
Mountain Hemlock
Tsuga mertensiana, known as Mountain Hemlock, is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Tulare County, California....
, and larch
Larch
Larches are conifers in the genus Larix, in the family Pinaceae. Growing from 15 to 50m tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains further south...
es. These forests are subject to infrequent, high-intensity fires.
Montane seral forest
Lodgepole pine forests interspersed with stands of quaking aspens are fire-resilient forests that dominate the central and north-central Rocky Mountains. Usually found between 2500 and 3200 m (8,202.1 and 10,498.7 ft) in Colorado, lodgepole pines and aspens grow rapidly after fire in mostly even-aged stands. In the Canadian Rockies, the lodgepole pine/quaking aspen forests occur in the foothills, mixed with white spruceWhite Spruce
Picea glauca is a species of spruce native to boreal forests in the north of North America, from central Alaska east to Newfoundland, and south to northern Montana, Minnesota, Wisconsin, Michigan, upstate New York, Vermont, New Hampshire, and Maine; there is also an isolated population in the...
and balsam poplar
Balsam poplar
The balsam poplars — also known as Populus sect. Tacamahaca — are a group of about 10 species of poplars, indigenous to North America and eastern Asia, distinguished by the balsam scent of their buds, the whitish undersides of their leaves, and the leaf petiole being round in cross-section...
. In the northern Canadian Rockies, black spruce
Black Spruce
Picea mariana is a species of spruce native to northern North America, from Newfoundland west to Alaska, and south to northern New York, Minnesota and central British Columbia...
also occurs in this biotic zone.
Intervals between fires typically range from 100 to 300 years. As evidenced by the fires in the Yellowstone National Park in 1988
Yellowstone fires of 1988
The Yellowstone fires of 1988 together formed the largest wildfire in the recorded history of the U.S.'s Yellowstone National Park. Starting as many smaller individual fires, the flames spread quickly out of control with increasing winds and drought and combined into one large conflagration, which...
, lodgepole pine forests are rejuvenated by crown fires that replace tree stands. Although aspen stands generally cover less than 1% of the landscape (for example, Rocky Mountain National Park, Grand Teton National Park), they are keystone communities
Keystone species
A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and...
for hundreds of birds and mammals and are especially important forage for deer and elk.
Spruce-fir forest
The subalpine forests of the Rocky Mountains are characterized by spruceSpruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
s and fir
Fir
Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...
s and are floristically and structurally similar to the boreal conifer forests to the north. Dominant tree species in the Colorado Rocky Mountains subalpine forests include Engelmann spruce
Engelmann Spruce
Picea engelmannii is a species of spruce native to western North America, from central British Columbia and southwest Alberta, southwest to northern California and southeast to Arizona and New Mexico; there are also two isolated populations in northern Mexico...
and subalpine fir
Subalpine Fir
The Subalpine Fir or Rocky Mountain Fir is a western North American fir, native to the mountains of Yukon, British Columbia and western Alberta in Canada; southeastern Alaska, Washington, Oregon, Idaho, western Montana, Wyoming, Utah, Colorado, New Mexico, Arizona, northeastern Nevada, and the...
. In the Black Hills of South Dakota, white spruce
White Spruce
Picea glauca is a species of spruce native to boreal forests in the north of North America, from central Alaska east to Newfoundland, and south to northern Montana, Minnesota, Wisconsin, Michigan, upstate New York, Vermont, New Hampshire, and Maine; there is also an isolated population in the...
replaces Engelmann spruce. Further north are the lodgepole pine
Lodgepole Pine
Lodgepole Pine, Pinus contorta, also known as Shore Pine, is a common tree in western North America. Like all pines, it is evergreen.-Subspecies:...
, Engelmann spruce, and alpine fir mix of the Alberta Mountain forests
Alberta Mountain forests
The Alberta Mountain forests are a temperate coniferous forests ecoregion of Canada.-Setting:This ecoregion covers the grand Rocky Mountains of Alberta including the eastern outliers of the Continental Ranges. Located almost entirely in Alberta and taking in the Alberta-British Columbia border from...
above 1675 metres (5,495.4 ft) of elevation. Stand-replacing fires typically occur at 200- to 400-year intervals. Widespread insect outbreaks in spruce-fir forests occur more frequently.
Subalpine white pine forest
On exposed, dry slopes at high elevations, subalpine white pine forests replace spruce-fir forests. Common species of the white pine forests include whitebark pineWhitebark Pine
Pinus albicaulis, known commonly as Whitebark Pine, Pitch Pine, Scrub Pine, and Creeping Pine occurs in the mountains of the Western United States and Canada, specifically the subalpine areas of the Sierra Nevada, the Cascade Range, the Pacific Coast Ranges, and the northern Rocky Mountains –...
in the northern Rocky Mountains, limber pine
Limber Pine
The Limber Pine, Pinus flexilis, is a species of pine tree-the family Pinaceae that occurs in the mountains of the Western United States, Mexico, and Canada. It is also called Southwestern White Pine and Rocky Mountain White Pine...
in the central and north-central Rocky Mountains, and bristlecone pine
Bristlecone pine
The bristlecone pines are a small group of pine trees that are thought to reach an age far greater than that of any other single living organism known, up to nearly 5,000 years....
in the southern Rocky Mountains. Typical intervals between fires range from 50 to 300 years. The white pines are tolerant of extreme environmental conditions and can be important postfire successional species. The whitebark pine is a keystone species
Keystone species
A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and...
in upper subalpine forests of the northern Rocky Mountains. However, the whitebark pine has been in decline due to White Pine Blister Rust: whitebark pine mortality in some areas exceeds 90%. Entire forest vistas, like that at Avalanche Ridge near Yellowstone National Park’s east gate, are expanses of dead, gray whitebarks.
Treeline vegetation
Treeline is the elevation above which trees cannot grow. It is controlled by a complex of environmental conditions, primarily soil temperatures and the length of the growing season—which becomes shorter with higher elevations. The elevation of treeline rises steadily at the rate of 100 metres (328.1 ft) per degree of latitude from the northern to the southern Rocky Mountains. Dominant treeline species, including spruces, firs, and white pines, often have a shrublike form in response to the extreme conditions at the elevational limits of their physiological tolerance; such dwarfed trees are called krummholzKrummholz
Krummholz or Krumholtz formation — also called Knieholz — is a particular feature of subarctic and subalpine tree line landscapes. Continual exposure to fierce, freezing winds causes vegetation to become stunted and deformed...
. Krummholz islands may actually move about 2 centimeters per year in response to the wind; they reproduce by vegetative layering on their lee sides, while dying back from wind damage on their windward sides. Under favorable climatic conditions, krummholz can assume an upright treelike form or can increase their cone crops and seedling establishment.
Alpine tundra
Alpine tundraAlpine tundra
Alpine tundra is a natural region that does not contain trees because it is at high altitude. Alpine tundra is distinguished from arctic tundra, because alpine soils are generally better drained than arctic soils...
is a complex of high-elevation meadow
Meadow
A meadow is a field vegetated primarily by grass and other non-woody plants . The term is from Old English mædwe. In agriculture a meadow is grassland which is not grazed by domestic livestock but rather allowed to grow unchecked in order to make hay...
s, fell (barren) field
Fellfield
A fellfield or fell field comprises the environment of a slope, usually alpine or tundra, where the dynamics of frost and of wind give rise to characteristic plant forms in scree interstices.-Soil dynamics:...
s, and talus
Scree
Scree, also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles...
(rock) slopes above treeline. Depending on latitude, treeline occurs between 3400 and 4000 m (11,154.9 and 13,123.4 ft) in the United States, and 2200 and 2450 m (7,217.8 and 8,038.1 ft) in Canada. Grasses and sedges dominate the meadow communities, and fe
FE
Fe or FE may refer to:* Iron * Fe , the f-rune of the Younger Futhark* Fe * Fe * "Fe" , a song by Jorge González...
ns (a type of wet meadow) and willows exist in wet soils. Vegetation in the alpine zone is similar to that in the Arctic: 47% of the plant species in the alpine zone of the Beartooth Mountains in Wyoming and Montana are also found in the Arctic. This high-diversity area includes alpine sagebrush, tufted hairgrass, clover
Clover
Clover , or trefoil, is a genus of about 300 species of plants in the leguminous pea family Fabaceae. The genus has a cosmopolitan distribution; the highest diversity is found in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes...
s, pussytoes, and succulents, and hundreds of grasses and wildflower species.
Fauna
The Rocky Mountains are important habitat for a great deal of well-known wildife, such as elkElk
The Elk is the large deer, also called Cervus canadensis or wapiti, of North America and eastern Asia.Elk may also refer to:Other antlered mammals:...
, moose
Moose
The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...
, mule
Mule Deer
The mule deer is a deer indigenous to western North America. The Mule Deer gets its name from its large mule-like ears. There are believed to be several subspecies, including the black-tailed deer...
and white-tailed deer
White-tailed Deer
The white-tailed deer , also known as the Virginia deer or simply as the whitetail, is a medium-sized deer native to the United States , Canada, Mexico, Central America, and South America as far south as Peru...
, pronghorns, mountain goat
Mountain goat
The Mountain Goat , also known as the Rocky Mountain Goat, is a large-hoofed mammal found only in North America. Despite its vernacular name, it is not a member of Capra, the genus of true goats...
s, bighorn sheep
Bighorn Sheep
The bighorn sheep is a species of sheep in North America named for its large horns. These horns can weigh up to , while the sheep themselves weigh up to . Recent genetic testing indicates that there are three distinct subspecies of Ovis canadensis, one of which is endangered: Ovis canadensis sierrae...
, black bears
American black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...
, grizzly bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...
s, wolves, coyote
Coyote
The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
s, lynx
Lynx
A lynx is any of the four Lynx genus species of medium-sized wildcats. The name "lynx" originated in Middle English via Latin from Greek word "λύγξ", derived from the Indo-European root "*leuk-", meaning "light, brightness", in reference to the luminescence of its reflective eyes...
es, and wolverine
Wolverine
The wolverine, pronounced , Gulo gulo , also referred to as glutton, carcajou, skunk bear, or quickhatch, is the largest land-dwelling species of the family Mustelidae . It is a stocky and muscular carnivore, more closely resembling a small bear than other mustelids...
s. For example, North America's largest herds of moose is in the Alberta-British Columbia foothills forests
Alberta-British Columbia foothills forests
The Alberta-British Columbia foothills forests are a temperate coniferous forests ecoregion of Canada.-Setting:This ecoregion covers two separate areas: the rolling foothills of the Rocky Mountains in Alberta, and further west a smaller area of the hills and valleys of central British Columbia...
. The status of most species in the Rocky Mountains is unknown however, due to incomplete information. Even basic regional information is not available on many nocturnal species (for example, bat
Bat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...
s, raccoon
Raccoon
Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...
s, and so forth); invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s; lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
s, moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
es, and fungi; and soil microorganisms.
European-American settlement of the mountains has adversely impacted native species. Examples of some species that are known to have declined include western toad
Western toad
The Western toad more commonly known as is a large toad species, between 5.6 and 13 cm long, of western North America. It has a white or cream dorsal stripe, and is dusky gray or greenish dorsally with skin glands concentrated within the dark blotches...
s, greenback cutthroat trout
Greenback cutthroat trout
The greenback cutthroat trout is the easternmost subspecies of cutthroat trout. This subspecies, once widespread, today occupies less than 1% of its historical range and is currently listed as threatened under the Endangered Species Act. It was adopted in 1994 as the state fish of...
s, white sturgeon
White sturgeon
The white sturgeon , also known as the Pacific sturgeon, Oregon sturgeon, Columbia sturgeon, Sacramento sturgeon, and California white sturgeon, is a sturgeon which lives along the west coast of North America from the Aleutian Islands to Central...
s, white-tailed ptarmigan
White-tailed Ptarmigan
The White-tailed Ptarmigan, Lagopus leucura, is the smallest bird in the grouse family. It is found in the mountains of the western United States, Canada and Alaska.-Description:...
s, trumpeter swan
Trumpeter Swan
The Trumpeter Swan, Cygnus buccinator, is the largest native North American bird, if measured in terms of weight and length, and is the largest living waterfowl species on earth. It is the North American counterpart of the European Whooper Swan.-Description:Males typically measure from and weigh...
s, and bighorn sheep
Bighorn Sheep
The bighorn sheep is a species of sheep in North America named for its large horns. These horns can weigh up to , while the sheep themselves weigh up to . Recent genetic testing indicates that there are three distinct subspecies of Ovis canadensis, one of which is endangered: Ovis canadensis sierrae...
. In the United States portion of the mountain range, apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
s such as grizzly bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...
s and gray wolves had been extirpated from their original ranges, but have partially recovered due to conservation measures and reintroduction. Other recovering species include the bald eagle
Bald Eagle
The Bald Eagle is a bird of prey found in North America. It is the national bird and symbol of the United States of America. This sea eagle has two known sub-species and forms a species pair with the White-tailed Eagle...
and the peregrine falcon
Peregrine Falcon
The Peregrine Falcon , also known as the Peregrine, and historically as the Duck Hawk in North America, is a widespread bird of prey in the family Falconidae. A large, crow-sized falcon, it has a blue-gray back, barred white underparts, and a black head and "moustache"...
. Species such as the black bear and mountain
Mountain
Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...
lion, many small mammals, and common bird and plant species are described as stable because, in most instances, the populations are persistent and not rapidly increasing or declining.
Invertebrates
Although most of the animals in the Rocky Mountains are invertebrates, little is known about this component of the region's fauna. As one entomologist stated, "We do not know how many species of moths and butterflies live in any state, county, or locality in North America". In a few areas in the western United States, information is available on the species richness of mothMoth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
s and butterflies. Most of the Rocky Mountain states and the Front Range of Colorado
Colorado Front Range
The Colorado Front Range is a colloquial geographic term for the most populous region of the state of Colorado in the United States. The area is located just east of the foothills of the Front Range, aligned in a north-south configuration on the western edge of the Great Plains, where they meet the...
in particular support high species richness of butterflies and moths. In Colorado, the diverse habitats—from prairie to tundra—support about 2,000 species of butterflies, moths, and skipper
Skipper (butterfly)
A skipper or skipper butterfly is a butterfly of the family Hesperiidae. They are named after their quick, darting flight habits. There are more than 3500 recognized species of skippers and they occur worldwide, but with the greatest diversity in the Neotropical regions of Central and South...
s; more than 1,000 species are in the Front Range. Some species of grasshopper
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...
s are unique to individual mountaintops in Colorado, New Mexico, Arizona, Nevada, and Utah. The Rocky Mountain locust
Rocky Mountain locust
The Rocky Mountain locust was the locust species that ranged through almost the entire western half of the United States until the end of the 19th century...
, a common pest to farmers in the 19th century, is now extinct. Heavy grazing along river valleys in Montana and Idaho is thought to have irreparably destroyed locust breeding areas.
Amphibians
Globally, populations of amphibians are declining in size as a result of habitat loss, predation by nonindigenous sport fishes, timber harvestForestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
, increased ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
radiation, and disease. The widespread declines of amphibian populations throughout the Rocky Mountains mirror these global trends. Western toad
Western toad
The Western toad more commonly known as is a large toad species, between 5.6 and 13 cm long, of western North America. It has a white or cream dorsal stripe, and is dusky gray or greenish dorsally with skin glands concentrated within the dark blotches...
s, once common between altitudes of 2300 and 4200 m (7,545.9 and 13,779.5 ft) throughout the central and northern Rocky Mountains, now occupy less than 20% of their previous range, from southern Wyoming to northern New Mexico. Eleven populations of western toads disappeared from the West Elk Mountains
West Elk Mountains
The West Elk Mountains are a mountain range in the west-central part of the US state of Colorado. They lie primarily within the Gunnison National Forest, and part of the range is protected as the West Elk Wilderness...
of Colorado between 1974 and 1982 because of a bacterial infection and, perhaps, multiple sublethal environmental causes. In the past two decades, western toads disappeared from 83% of their historical range in Colorado and from 94% of Wyoming sites. Populations of northern leopard frog
Northern Leopard Frog
The Northern Leopard Frog is a species of leopard frog from the true frog family, native to parts of Canada and United States. It is the state amphibian of Minnesota and Vermont.-Physical description:...
s are significantly declining throughout the Rocky Mountains.
Greenback cutthroat trout
Greenback cutthroat trout
The greenback cutthroat trout is the easternmost subspecies of cutthroat trout. This subspecies, once widespread, today occupies less than 1% of its historical range and is currently listed as threatened under the Endangered Species Act. It was adopted in 1994 as the state fish of...
historically inhabited the cold-water streams in the mountains of Colorado. The species was near extinction by the early 20th century because of broad-scale stocking of these streams with nonindigenous brown trout from Europe and rainbow trout from the Pacific Coast, and because of land and water exploitation, mining, and logging. Native genetic diversity is now lost in greenback cutthroat trout because this species hybridizes with the introduced fishes. Interagency efforts began in 1959 to save the species. With viable populations now at 48 sites, the greenback cutthroat trout is one of the few species that will be removed from the endangered species list. Three of the four other native subspecies of the cutthroat trout are extinct.
Most aquatic ecosystems in the Rocky Mountains are now influenced by nonindigenous brown trout
Brown trout
The brown trout and the sea trout are fish of the same species....
and rainbow trout
Rainbow trout
The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....
. One of the more subtle, yet devastating, trends in the Rocky Mountain fishery is loss of genetic diversity in native fishes resulting from introductions of nonindigenous fishes. For example, only 15 of 32 lakes in Glacier National Park, Montana, contain pure genetic strains of the native cutthroat trout. The others contain totally nonindigenous fishes or hybrids with the introduced Yellowstone cutthroat trout or rainbow trout. Introductions of nonindigenous fishes to improve the sport fishery have compromised about 84% of the historical range of the native cutthroat trout.
Yellowstone cutthroat trout
Yellowstone Lake
Yellowstone Lake is the largest body of water in Yellowstone National Park, The lake is 7,732 feet above sea level and covers with 110 miles of shoreline. While the average depth of the lake is 139 feet its deepest spot is at least 390 feet...
in Yellowstone National Park
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...
, Wyoming, is the site of the most recent catastrophic species invasion. The Washington Post reported that the nonindigenous lake trout
Lake trout
Lake trout is a freshwater char living mainly in lakes in northern North America. Other names for it include mackinaw, lake char , touladi, togue, and grey trout. In Lake Superior, they can also be variously known as siscowet, paperbellies and leans...
, a native of the Great Lakes, had been insidiously introduced into one of the nation's premier fisheries. The native Yellowstone cutthroat trout
Yellowstone cutthroat trout
The Yellowstone cutthroat trout is a subspecies of the cutthroat trout and is a freshwater fish in the salmon family of the order Salmoniformes. Native only to a few U.S...
may not compete well with lake trout because lake trout eat cutthroat trout. The potential ecological repercussions are staggering. If populations of cutthroat trout decline, grizzly bears could lose an important posthibernation food because the native cutthroat trout spawn in the streams and are easy prey for the bears, whereas the nonindigenous lake trout spawn in deep water.
White sturgeon
The largest freshwater fish in the Rocky Mountains (and North America) is also in trouble. The white sturgeonWhite sturgeon
The white sturgeon , also known as the Pacific sturgeon, Oregon sturgeon, Columbia sturgeon, Sacramento sturgeon, and California white sturgeon, is a sturgeon which lives along the west coast of North America from the Aleutian Islands to Central...
historically ranged from the mouth of the Columbia River
Columbia River
The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...
to the Kootenai River upstream to Kootenai Falls, Montana. The Kootenai River population of the white sturgeon is unstable and declining in size; fewer than 1,000 remain, 80% are older than 20 years, and virtually no recruitment has occurred since 1974, soon after Libby Dam in Montana began regulating flows.
Bald eagles
Bald Eagle
The Bald Eagle is a bird of prey found in North America. It is the national bird and symbol of the United States of America. This sea eagle has two known sub-species and forms a species pair with the White-tailed Eagle...
s. Bald eagle populations are now recovering after years of hunting, habitat destruction, and pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
-induced deaths. In the early 1970s, Colorado had just one breeding pair of bald eagles but by 1993 biologists counted 19 breeding pairs. In Wyoming nesting attempts increased from 20 in 1978 to 42 in 1988. The bald eagle is not yet fully recovered, however; pesticide residues continue to inhibit bald eagle reproduction, and habitat loss and lead poisoning remain serious threats.
Peregrine falcons
Peregrine falconPeregrine Falcon
The Peregrine Falcon , also known as the Peregrine, and historically as the Duck Hawk in North America, is a widespread bird of prey in the family Falconidae. A large, crow-sized falcon, it has a blue-gray back, barred white underparts, and a black head and "moustache"...
s are cliff-dwelling raptors that once ranged through most of North America. Like the bald eagle, this species was driven to near extinction by pesticides. By 1965 fewer than 20 breeding pairs were known west of the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
. Even in the Greater Yellowstone ecosystem
Greater Yellowstone Ecosystem
The Greater Yellowstone Ecosystem is one of the last remaining large, nearly intact ecosystems in the northern temperate zone of the Earth and is partly located in Yellowstone National Park. Conflict over management has been controversial, and the area is a flagship site among conservation groups...
, federal spruce budworm
Spruce Budworm
Spruce budworms and relatives are a group of closely related insects in the genus Choristoneura. Most are serious pests of conifers. There are nearly a dozen Choristoneura species, subspecies, or forms, with a complexity of variation among populations found throughout much of the United States and...
control relied on DDT
DDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....
, which accumulates in the food chain, causing eggshell thinning and reduced reproductive success in raptors. Six breeding pairs of American peregrine falcons were found in Colorado in the early 1970s. By 1994, 53 pairs were breeding in Colorado. In Wyoming, Montana, and Idaho combined, 8 of 59 historical sites were used by falcons in 1987. Low breeding densities, reproductive isolation, habitat loss, and pesticide poisoning on wintering grounds remain threats to peregrine falcon recovery.
White-tailed ptarmigans
White-tailed Ptarmigan
The White-tailed Ptarmigan, Lagopus leucura, is the smallest bird in the grouse family. It is found in the mountains of the western United States, Canada and Alaska.-Description:...
s have been monitored in Rocky Mountain National Park
Rocky Mountain National Park
Rocky Mountain National Park is a national park located in the north-central region of the U.S. state of Colorado.It features majestic mountain views, a variety of wildlife, varied climates and environments—from wooded forests to mountain tundra—and easy access to back-country trails...
, Colorado, since 1966. Short-term population cycles are well documented in populations that are not hunted but not in populations outside the park, which are hunted. Although detailed population size data are available from more than 28 years of monitoring, scant information is available on habitat change, predator populations, or other potential causes of change in ptarmigan populations. A 2-year study revealed lower ptarmigan densities where elk use was greater, although characteristics of willow, which is ptarmigan habitat, did not significantly differ in the high- and low-use elk sites. Furthermore, a 2-year study of ptarmigan habitat cannot explain 28-year trends in population size. Habitat loss and other factors partly responsible for ptarmigan deaths—such as predation and competition—were not studied during the 28-year period.
Trumpeter swans
Trumpeter Swan
The Trumpeter Swan, Cygnus buccinator, is the largest native North American bird, if measured in terms of weight and length, and is the largest living waterfowl species on earth. It is the North American counterpart of the European Whooper Swan.-Description:Males typically measure from and weigh...
populations were seriously threatened in the 1930s; fewer than 70 birds were thought to exist. Now protected from hunting, more than 1,500 swans winter in the Greater Yellowstone ecosystem, but the size of the breeding population has declined in recent years because of habitat loss.
Neotropical migrant songbirds
Many forest-dwelling songbirdSongbird
A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...
s breed in the Rocky Mountains and winter in Central and South America. Wildlife biologists suspect that population size declines in the songbirds may be partly the result of increased predation and brood parasitism. Brood parasitism by brown-headed cowbird
Brown-headed Cowbird
The Brown-headed Cowbird is a small brood parasitic icterid of temperate to subtropical North America. They are permanent residents in the southern parts of their range; northern birds migrate to the southern United States and Mexico in winter, returning to their summer habitat around March or...
s, for example, increases as a result of nearby logging. In conifer forests in west-central Idaho, common songbirds benefited from timber harvest, whereas the abundances declined of rare species that inhabit old-growth forests (hermit thrush, Swainson's thrush, and pileated woodpecker).
Grizzly bears
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...
s once roamed throughout the Rocky Mountains and the western Great Plains. They were hunted relentlessly by European settlers in the 19th century and early 20th century. The last known grizzly bear in Colorado was killed in 1979. The decline of the bears to just 2% of their original range tells of the human-caused extirpation of large predators in the Rocky Mountain region. Only 700-900 grizzly bears may be alive today in the conterminous United States. During the last 20 years, about 88% of all grizzly bears studied in the northern Rocky Mountains were killed by humans.
Gray wolves
Gray wolves once were common throughout the Rocky Mountains. They were shot, poisoned, and trapped into local extinction by early settlers and federal agents. The last gray wolf in Colorado was killed in 1940, and the wolf was first listed as an endangered species in 1967. Wolves from southeastern British Columbia recolonized northwestern Montana in 1986; by 1994 the population had grown to 7 packs and about 70-75 wolves. Wolves from Glacier National Park have dispersed naturally as far away as northeastern Idaho and just south of Yellowstone National Park. A wolf was shot near Yellowstone National Park in 1992. From January to March 1995, 15 adult wolves from 7 different packs in Canada were introduced into central Idaho wilderness areas. Several pairs have bred and produced the first litters of wolf pups born in Idaho in more than 50 years. Fourteen wolves (three family groups) were released in the Yellowstone National Park in late March 1995. A total of 66 wolves were released to the two areas in this manner in January 1995 and January 1996.2005 estimates of wolf populations in the two recovery zones reflect the success the species has had in both areas:
- Greater Yellowstone Area: 325
- Central Idaho: 565
These numbers, added with the estimated number of wolves in northwestern Montana (130), puts the total number of wolves in the Northern Rocky Mountain recovery area at over 1000 individuals. This includes approximately 134 packs (two or more wolves traveling together) and 71 breeding pairs (male and female that successfully rear a litter of at least two until Dec. 31). The recovery goal for the area was 30 breeding pairs total, and this number has been surpassed for some time.
The restoration of the gray wolf to the Yellowstone National Park not only restores an important ecosystem component (the wolf) and process (predation by wolves) to bring the park into better ecological balance, but it also is economically sound. After weighing the costs (including full reimbursement to ranchers for the loss of livestock) and benefits (increased revenues from hunting and tourism), economists estimated (before the actual restoration took place) a net $18 million return during the first year after the wolves were returned, and about $110 million in 20 years. More tourists are expected to visit the area of the Yellowstone National Park and to stay longer in hope of hearing or seeing wolves in the wild. Compensatory payments to ranchers for the loss of cattle and sheep to wolves averaged about $1,800 per year in northwestern Montana.
North American elk, deer, pronghorns, and moose
Mule Deer
The mule deer is a deer indigenous to western North America. The Mule Deer gets its name from its large mule-like ears. There are believed to be several subspecies, including the black-tailed deer...
and white-tailed deer
White-tailed Deer
The white-tailed deer , also known as the Virginia deer or simply as the whitetail, is a medium-sized deer native to the United States , Canada, Mexico, Central America, and South America as far south as Peru...
combined) may be heading in opposite directions. The number of elk has increased steadily in Colorado and Wyoming, whereas the abundances of deer are showing signs of decline. Elk on U.S. Forest Service lands in the Rocky Mountains increased from 268,000 in 1965 to 372,000 in 1984. Similarly, the number of elk on Bureau of Land Management lands rose from 35,000 in 1966 to 114,000 in 1985. Meanwhile, the number of deer on U.S. Forest Service lands declined from 1,742,000 in 1965 to 1,197,000 in 1984. Deer populations also declined on Bureau of Land Management lands. Thus, in some areas in the last 20 years, the abundances of elk have increased by about 40%, whereas deer have decreased by about 30%. Possible reasons for the increase in elk populations include mild winters, range extension into lowlands and highlands, increased adaptability to human-modified landscapes, and lack of predation in spite of increased hunting. The causes of the deer population declines remain unknown but may include excessive harvest in the 1970s and habitat overlap with elk, intensifying competition for similar resources. Note, however, that deer population in the rest of the United States has increased fiftyfold between 1900 and 2005, as hunting has been limited and open space has been preserved.
Pronghorn populations have fluctuated but generally have increased in the past 20 years in Colorado and Wyoming. Moose populations have increased 50% since 1980 in Wyoming and have been rapidly increasing since the introduction into Colorado in 1978 and 1979.
Bighorn sheep
Bighorn Sheep
The bighorn sheep is a species of sheep in North America named for its large horns. These horns can weigh up to , while the sheep themselves weigh up to . Recent genetic testing indicates that there are three distinct subspecies of Ovis canadensis, one of which is endangered: Ovis canadensis sierrae...
are at only about 2% to 8% of their sizes at the time of European settlement. Causes for the rapid decline from 1870 through 1950 included unregulated harvesting, excessive grazing of livestock on rangeland
Rangeland
Rangelands are vast natural landscapes in the form of grasslands, shrublands, woodlands, wetlands, and deserts. Types of rangelands include tallgrass and shortgrass prairies, desert grasslands and shrublands, woodlands, savannas, chaparrals, steppes, and tundras...
s, and diseases transmitted by domestic sheep
Domestic sheep
Sheep are quadrupedal, ruminant mammals typically kept as livestock. Like all ruminants, sheep are members of the order Artiodactyla, the even-toed ungulates. Although the name "sheep" applies to many species in the genus Ovis, in everyday usage it almost always refers to Ovis aries...
. In recent years, 115 translocations were made to restore bighorn sheep into the Rocky Mountains and into many national parks. Only 39% of the 115 bighorn sheep translocations are persisting in 6 Rocky Mountain states. Populations of 100 or more sheep now occur in 10 national park units, populations of 100-200 sheep in 5 units, and populations of more than 500 sheep in 5 units. Populations of fewer than 100 animals exist in 5 other park units.
Beaver
BeaverBeaver
The beaver is a primarily nocturnal, large, semi-aquatic rodent. Castor includes two extant species, North American Beaver and Eurasian Beaver . Beavers are known for building dams, canals, and lodges . They are the second-largest rodent in the world...
s once played important roles in shaping vegetation patterns in riparian and meadow communities in the Rocky Mountains. Studies of beaver populations in one small area in Yellowstone National Park (Tower Junction area) in the early 1920s reported 232 beavers and extensive beaver dams. Repeated surveys in the same area in the early 1950s and in 1986 revealed no beavers or dams. Beavers need aspen
Aspen
Populus section Populus, of the Populus genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by...
s or tall willow
Willow
Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...
s for food and building materials—resources that are made scarce by lack of both fires and floods and by herbivory by elk, moose, and domestic livestock. Beaver ponds are known to maintain fish and invertebrate populations and to create and maintain riparian zones that are critical to wildlife, yet the beaver is virtually absent in many areas.