The Great Plains extend from Mexico in the south through the central United States to central Canada. Many sub-regions exist within the area.
The region is home to many animals, including American bison, pronghorn, mule, and white tailed deer, and birds such as ducks, hawks, and sparrows, along with many invertebrate species.
Settlement of "America's breadbasket" led to ecological destruction. Widespread agriculture led to the near-complete extermination of the American bison in the late 1800s and the reduction of the tallgrass prairie to less than 1% of its former extent.[2] The plains are now largely agricultural, with large ranches and farms. However, restoration efforts in some areas, like American Prairie in Montana, are leading to the gradual expansion of the threatened ecosystem.
Climate
The climate is very unique due to the many different wind patterns that flow throughout the region, traveling from east to west and north to south. Due to the fact that this region is geographically positioned in the center of the United States and Canada, there are many different air mass types that pass through and affect the constantly shifting weather patterns. This means that the Great Plains has a less consistent climate due to its central location than a region located on the coast. This is shown by how the western Great Plains is semi-arid, while the eastern portion of the Great Plains is much wetter. It has the four seasons of summer, autumn, winter, spring, but each season brings new extremes in the weather conditions. For example, the southern portions of the region typically experience 70 to 100 days each year over 90°F, while the northern portions typically see only 10 to 20 days above 90°F. It's the air masses that come in from all directions that bring this variable climate.
Each air mass type brings in different temperature and moisture properties. The continental polar air mass brings in cold and dry air from central Canada, traveling south across the region. The continental tropical air mass comes in from the Gulf of Mexico and the Caribbean, bringing in hot and dry air while moving north. The maritime tropical air mass comes from the southwest United States and Northern Mexico, and it tends to bring in warm and moist air, but sometimes the air that comes in is dry. The last air mass that affects this ecoregion is the maritime polar air mass. It comes in from the Pacific Ocean and moves east over the mountain regions. It brings in cool moist air that changes to warm dry air after moving over the mountains. These air masses cause the seasons to be very extreme and drastic. The winter time brings harsh and varied weather. The midsummer months bring in warm moist and dry air, depending on the area within the region and what air masses affect those areas.
Paralleling the varying climate patterns is the precipitation. The areas nearest the Gulf of Mexico, where the atmospheric moisture is greatest, will receive more than forty inches of precipitation annually. The wastern areas of the region, such as Montana, receive less than fourteen inches annually. In the winter time, the southern region has less than an inch of snowfall, while the northern regions receive more than forty. The spring time is also a season that brings much precipitation to the Great Plains through the cold, dry air masses that interact with the air masses from the Gulf of Mexico, creating outbreaks of severe thunderstorms with heavy rainfall, high winds, hail, and tornadoes. Most of the winter season in the Northern Plains actually has a snow blanket over a majority of the winter season. This shows how there is consistent precipitation over the region during the winter months, while in the heat of summer there is more chance for drought with sporadic heavy rains.
Climate change
Due to the highly variable climatic regimes across the Great Plains, many aspects of climate change are not expected to affect all areas of the eco-region equally. In regards to precipitation, this means an exacerbation of extremes where dry areas in the south are expected to get drier and wetter areas in the north to get wetter. In turn this will increase the intensity of already problematic droughts across the region as well as creating the potential for flooding in the wetter north. The percent change in precipitation for both areas is dependent upon different emission scenarios; with higher emission levels in the future being conducive to greater extremes. Dramatic increases in average annual temperature are also expected, with average winter temperatures already having risen 7°F in the past 30 years.[citation needed] These increased temperatures are expected to cause warmer winters with warmer springs as well as hotter summers in the south-central plains.
In regards to the biotic communities of the Great Plains, the potential repercussions of these changes could be felt in a variety of ways. Extreme droughts could kill vegetation, potentially causing the collapse of agriculture in some areas increasing the risk of erosion. This loss of growing medium, nutrients and moisture retention could prove to be a devastating blow to any ecosystem that may try to reclaim the land as well as leaving the barren areas susceptible to more stress tolerant invasive species. Additionally, droughts could dry up prairie potholes essential for the breeding of many species, especially migratory waterbirds. Changes in temperature have the potential to cause range shifts for some species, possibly increasing competition between species that never previously shared a range and even decreasing populations of or eliminating species that can't effectively spread or adapt to new conditions. Temperature changes, especially earlier springs, could also cause changes in phenology which could put organisms out of sync with their ecosystem and eventually lead to their decline. Other potential issues include a loss of biodiversity and decreased productivity within the ecoregion.
Geology, topography, and soil
Originally massive glaciers that formed in Canada moved southward over the central and low-elevation plains located in the United States. These glaciers and their deposits had great effects on the surface of the land they covered, with biggest changes occurring between the Missouri and Ohio Rivers. One key abiotic factor that affects Great Plains is weather in relation to the low- relief topography as result of glacial smoothing. Low relief topography is used to describe areas that have little difference in altitude throughout the region. Low relief landscapes, such as the various types of grasslands found throughout the Great Plains, have an effect on rainfall distribution. Rainfall in this ecoregion increases from west to east resulting in various types of prairie grasslands.
Topography in the Great Plains actually affects soil composition in areas of different elevation. Higher accumulations of soil organic matter are found in lower landscape positions such as grasslands than in higher landscape positions such as buttes, mesas, and escarpments found throughout the north western areas of the ecoregion. In the short grass regions such as the High Plains of the Great Plains, soil typically stores no moisture annually because vegetation depends on whatever water exists in the soil during dry spells. Soil in this region is typically drained, composed of loam and clay. Specialized plants such as various species of forbs and shrubs utilize this soil. Some adaptations that plants have acquired in this region include massive and intricate root systems that make up around 90 percent of the plants biomass. This allows the plants to stay securely planted in ground and have roots that reach moisture in the deepest sections of the soil. In tall grass prairies, water is less scarce and the soil contains more moisture resulting a smaller root biomass.
Hydrology
The Great Plains ecoregion comprises a number of water bodies which play an integral role in its unique hydrology. There are thirteen rivers that are considered to be located within the Great Plains region. Most of the rivers that originate in the Rocky Mountain region in the west are a source of irrigation for farms. These rivers benefit greatly from melted snow pack from the mountains, which feeds the rivers during the growing season. Another water source in the Great Plains is wetlands, with the greatest concentrations located in the northern glaciated region of the plains. Up to half of areas in the northern Great Plains are wetlands. These, as well as the wetlands in the NebraskaSandhills, serve as major breeding, staging, and nesting habitat for migratory waterfowl. Playas, or temporary lakes, in the southwestern United States also provide habitats for migrating waterfowl from Canada and the United States during the winter.
A playa lake during the wet season. Playa lakes are important breeding grounds for migratory waterfowl.
The Ogallala aquifer, or the High Plains aquifer, is an integral fresh water source for the entirety of the Great Plains region, providing drinking water to 80% of the population and irrigating 13 million acres of land. Precipitation, seasonal lakes, and prehistoric water reserves serve as sources of water for the aquifer, which lies beneath 174,000 square miles of the Central and Southern regions, contains 3.25 billion acre-feet of water, and which is used by around 200,000 irrigation wells. Around 95% of the water pumped out of the aquifer is used for irrigation for the extensive areas of farmland in the Great Plains. The playa lakes, or seasonal lakes, are the primary sources of recharge for the aquifer, with an average of 0.5 inches per year as the recharge rate for the entire High Plains region. Population, agricultural, and economic growth have increased the demand for water in the areas that rely on the aquifer, causing the average level of water in the aquifer to drop by 13 feet since 1950.
Environmental threats
The environmental threats that pose the most harm toward the Great Plains include water depletion, land degradation, and increasing temperature change. The winter months have become much warmer in the Plains, whether it is in the North, near North Dakota, or in the South, throughout Texas and bordering states, excluding the winters of 2014, 2015, and 2016. Though the winters are getting warmer, it is predicted that the summer months will have a greater increase than the temperatures in the winter months.[3] The effects of this increase in temperature is predicted to cause more frequent extreme events such as heat waves, droughts, and heavy rainfall. This great increase in temperature will be the cause of the increased depletion of already declining water sources. Depleting water in the Great Plains will affect all populations in a negative way. "Most of the water used in the Great Plains comes from the High Plains aquifer (sometimes referred to by the name of its largest formation, the Ogallala aquifer), which stretches from South Dakota to Texas."[3] Conserving water in the Great Plains is one of the most important factors in keeping the Great Plains sustainable. It is also very important that farmers who use the land are sustainable in their practices. Since there are many different sustainable ways of farming, it is hard to decide which way would be the most sustainable. However, according to the Annals of the Association of American Geographers, farmers are not very likely to change their ways, leaving the outcome questionable for the Great Plains.[4] "What is really needed are new methods, concepts, and measuring techniques".[4] The biggest challenge in changing the sustainability in such a large ecoregion is getting the a large portion of farmers using the land to practice in a way that does not harm the land, which poses to be a challenge since there are so many different farming practices. "Prairie conservation requires: 1) New technology...to prioritize and set context to save prairie, 2) ecologically based initiatives to reverse significant losses in area and condition of native grasslands, 3) rethinking of standardized tools in the range management profession, and 4) a new natural resource agency."[5]
Habitats
There are many different types of habitats in the Great Plains, because of its great size. Differences in latitude and longitude, as well as differences in elevation and proximity to water, shape the ecosystems of these grasslands.
Tallgrass prairies
Flowering big bluestem, a characteristic tallgrass prairie plant
Tallgrass prairies are found in the southern and eastern section of the great plains. It once covered 170 million acres in North America. Now, less than 4% remains, mostly in the KansasFlint Hills.[2] This area is lower and wetter than the High Plains and is warmer than many other regions. Some areas here receive more than 40 inches of annual precipitation. Grasses here include bluestems, along with many other species. Historically, many areas of the Midwest that are now forested were once tallgrass prairie. Fire is very important in maintaining the prairie. Without it, many areas can become forested.
Short-grass prairies
Short-grass prairies are found in the high plains of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming. 70% of the original short-grass prairie remains today, making it one of the least fragmented prairie ecosystems.[6]
Characteristic flora
Grasslands occur where there is insufficient rain to support trees, thus only grasses and a few shrubs can survive. There are three kinds of grasslands on the great plains, short grass prairie, mixed grass, and long grass prairie. In each of these, grass species serve all the keystone roles. They provide food, shelter, act as larval hosts for numerous species and acted as the primary food for buffalo. These grasses are of vital importance to the ecosystem and protect the soil from the strong winds that whip through the prairie. They are all drought resistant and have strong short roots that hold the soil in place.[1]
In short grass prairie there are two dominant plants, buffalo grass (Bouteloua dactyloides), is a strong and hardy grass that is the favorite of grazers. The second is blue grama (Bouteloua gracilis), which is essential for soil retention.[7] In tallgrass prairie there are four dominant species, big bluestem grass (Andropogen gerardii), Indian grass (Sorghastrum nutans), switch grass (Panicum virgatum), and little bluestem (Schizachyrium scoparium). Big bluestem grass is 4–8 feet tall and was the favorite food of the buffalo.
Characteristic fauna
A "keystone species" is a species that "has disproportionate importance in their community."[8] Keystone species on the great plains include the bison and the prairie dog. Many other species live on the grasslands, including deer, rabbits, mice, and many types of birds.
Prairie dogs
Two black-tailed prairie dogs
In the Great Plains, the prairie dog is a keystone species. Studies comparing species abundances in areas of colonization against areas with no prairie dog colonization show clear evidence that the prairie dog does have a significant impact on its surroundings by altering vegetation and therefore affecting habitat and food availability for other species. There is a great mosaic of vegetative diversity within the Great Plains due to the prairie dog's extensive grazing on long grasses. This mosaic supports a variety of small mammals. In addition to altering vegetation, the prairie dog also creates habitat for many other organisms by creating extensive tunnel systems that other small mammals such as the desert cottontail, striped skunk and deer mouse use for shelter. A strong characteristic of keystone species is their ability to create and modify other organism's habitats and it is evident that the prairie dog does this. In conclusion, the prairie dog is an iconic animal species North America. Its close link to the ecology and structure of the Great Plains make it the defining keystone species of the ecoregion.
There are several types of prairie dogs in the ecoregion, including black-tailed, white-tailed, and Gunnison's, though the black-tailed is the most abundant and widespread.
The American bison (Bison bison) once roamed the Great Plains grasslands in vast herds. Their total population numbers were once in the tens of millions and spanned most of North America.[9] The dwindling numbers severely reduced their ecological impact. The bison's large influence as a grazer, a major converter of plant to animal biomass, and a key link in nutrient recycling have been lost.[10] Their grazing habits were pivotal in allowing for the establishment of much of the biodiversity observed today in the region, including the prairie dog.[9] Along with fire, bison were responsible for the removal of excess plant material that accumulated in the grassland.[10] With the accumulation of dead plant material, seed germination is greatly hindered and biodiversity is held stagnant. The purging of excess biomass helped to promote and maintain biodiversity among plant species on the plains. While the American bison once played a keystone role in both the establishment and maintenance of the Great Plain's current biodiversity, the severely reduced population that still remains has little ecological effect on the Great Plains ecoregion.
Endangered species
An Indiana bat (Myotis sodalis)
The Indiana bat is an important predator within the Great Plains. The Indiana bat perpetuates biodiversity by consuming moths, mosquitoes, and flies under the night sky. This bat sleeps in abandoned caves and mines during the winter months for hibernation and under tree bark during the warmer seasons. This Indiana bat is endangered mainly due to human disturbance within the caves. However, help is underway to protect this species. Besides showing hospitality to these bats, gates are going up to prohibit visitors from entering the caves and mines during the hibernation months. Studies are also ensuing to try and discover other factors diminishing the Indiana bat's population.[11]
Another dwindling species of the Great Plains is the Small White Lady's Slipper. There are only 100 of these orchids left. Invasive species and land conservationists have equally played a part in demolishing this population; as well as people plucking these flowers. The only working conservation action to salvage the Small White Lady's Slippers requires controlled fires; eliminating surrounding invasive plants and providing the Small White Lady's Slippers with enough surface area and nutrients to repopulate. This plant needs to grow next to a fungus in order to survive because of the symbiotic relationship between them.[12]
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Related Research Articles
Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type. Temperate grassland regions include the Pampas of Argentina, Brazil and Uruguay, and the steppe of Ukraine, Russia and Kazakhstan. Lands typically referred to as "prairie" tend to be in North America. The term encompasses the area referred to as the Interior Lowlands of Canada, the United States, and Mexico, which includes all of the Great Plains as well as the wetter, hillier land to the east.
Temperate grasslands, savannas, and shrublands is a terrestrial biome defined by the World Wide Fund for Nature. The predominant vegetation in this biome consists of grass and/or shrubs. The climate is temperate and ranges from semi-arid to semi-humid. The habitat type differs from tropical grasslands in the annual temperature regime as well as the types of species found here.
A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area.
The Great Basin Desert is part of the Great Basin between the Sierra Nevada and the Wasatch Range. The desert is a geographical region that largely overlaps the Great Basin shrub steppe defined by the World Wildlife Fund, and the Central Basin and Range ecoregion defined by the U.S. Environmental Protection Agency and United States Geological Survey. It is a temperate desert with hot, dry summers and snowy winters. The desert spans large portions of Nevada and Utah, and extends into eastern California. The desert is one of the four biologically defined deserts in North America, in addition to the Mojave, Sonoran, and Chihuahuan Deserts.
The tallgrass prairie is an ecosystem native to central North America. Historically, natural and anthropogenic fire, as well as grazing by large mammals provided periodic disturbances to these ecosystems, limiting the encroachment of trees, recycling soil nutrients, and facilitating seed dispersal and germination. Prior to widespread use of the steel plow, which enabled large scale conversion to agricultural land use, tallgrass prairies extended throughout the American Midwest and smaller portions of southern central Canada, from the transitional ecotones out of eastern North American forests, west to a climatic threshold based on precipitation and soils, to the southern reaches of the Flint Hills in Oklahoma, to a transition into forest in Manitoba.
The Sandhills, often written Sand Hills, is a region of mixed-grass prairie on grass-stabilized sand dunes in north-central Nebraska, covering just over one quarter of the state. The dunes were designated a National Natural Landmark in 1984.
The Flint Hills, historically known as Bluestem Pastures or Blue Stem Hills, are a region in eastern Kansas and north-central Oklahoma named for the abundant residual flint eroded from the bedrock that lies near or at the surface. It consists of a band of hills stretching from Kansas to Oklahoma, extending from Marshall and Washington Counties in the north to Cowley County, Kansas and Kay and Osage Counties in Oklahoma in the south, to Geary and Shawnee Counties west to east. Oklahomans generally refer to the same geologic formation as the Osage Hills or "the Osage."
Pawnee National Grassland is a United States National Grassland located in northeastern Colorado on the Colorado Eastern Plains. The grassland is located in the South Platte River basin in remote northern and extreme northeastern Weld County between Greeley and Sterling. It comprises two parcels totaling 193,060 acres (78,130 ha) largely between State Highway 14 and the Wyoming border. The larger eastern parcel lies adjacent to the borders of both Nebraska and Wyoming. It is administered in conjunction with the Arapaho-Roosevelt National Forest from the U.S. Forest Service office in Fort Collins, with a local ranger district office in Greeley.
Aspen parkland refers to a very large area of transitional biome between prairie and boreal forest in two sections, namely the Peace River Country of northwestern Alberta crossing the border into British Columbia, and a much larger area stretching from central Alberta, all across central Saskatchewan to south central Manitoba and continuing into small parts of the US states of Minnesota and North Dakota. Aspen parkland consists of groves of aspen, poplar and spruce, interspersed with areas of prairie grasslands, also intersected by large stream and river valleys lined with aspen-spruce forests and dense shrubbery. This is the largest boreal-grassland transition zone in the world and is a zone of constant competition and tension as prairie and woodlands struggle to overtake each other within the parkland.
The Texas Blackland Prairies are a temperate grassland ecoregion located in Texas that runs roughly 300 miles (480 km) from the Red River in North Texas to San Antonio in the south. The prairie was named after its rich, dark soil. Less than 1% of the original Blackland prairie vegetation remains, scattered across Texas in parcels.
The great bison belt is a tract of rich grassland that ran from Alaska to the Gulf of Mexico from around 9000 BC. The great bison belt was supported by spring and early summer rainfall that allowed short grasses to grow. These grasses retain their moisture at the roots which allowed for grazing ungulates such as bison to find high-quality nutritious food in autumn.
The Konza Prairie Biological Station is a 8,616-acre (3,487 ha) protected area of native tallgrass prairie in the Flint Hills of northeastern Kansas. "Konza" is an alternative name for the Kansa or Kaw Indians who inhabited this area until the mid-19th century. The Konza Prairie is owned by The Nature Conservancy and Kansas State University.
The shortgrass prairie is an ecosystem located in the Great Plains of North America. The two most dominant grasses in the shortgrass prairie are blue grama and buffalograss, the two less dominant grasses in the prairie are greasegrass and sideoats grama. The prairie was formerly maintained by grazing pressure of American bison, which is the keystone species. Due to its semiarid climate, the shortgrass prairie receives on average less precipitation than that of the tall and mixed grass prairies to the east.
The Geography of Oklahoma encompasses terrain and ecosystems ranging from arid plains to subtropical forests and mountains. Oklahoma contains 10 distinct ecological regions, more per square mile than in any other state by a wide margin. It is situated in the Great Plains and U.S. Interior Highlands region near the geographical center of the 48 contiguous states. Usually considered part of the South Central United States, Oklahoma is bounded on the east by Arkansas and Missouri, on the north by Kansas, on the northwest by Colorado, on the far west by New Mexico, and on the south and near-west by Texas.
The Northern short grasslands includes parts of the Canadian provinces of Alberta and Saskatchewan, and the American Great Plains states of Montana, North Dakota, Wyoming, South Dakota and Nebraska. One of 867 terrestrial ecoregions defined by the World Wide Fund for Nature, the United States Environmental Protection Agency (EPA) further breaks this ecoregion into the Northwestern Glaciated Plains and Northwestern Great Plains.
The Northern tall grasslands is one of 867 terrestrial ecoregions defined by the World Wide Fund for Nature. This ecoregion largely follows the Red River Valley in the Canadian province of Manitoba and the American states of North Dakota and Minnesota.
The Central tall grasslands are a prairie ecoregion of the Midwestern United States, part of the North American Great Plains.
The Central Great Plains are a semiarid prairie ecoregion of the central United States, part of North American Great Plains. The region runs from west-central Texas through west-central Oklahoma, central Kansas, and south-central Nebraska.
Mediterranean California is a Level I ecoregion of North America designated by the Commission for Environmental Cooperation (CEC) in its North American Environmental Atlas. The region is present only in California and Baja California.
1 2 Cambridge University (2009). Global Climate Change Impacts in the United States. New York: US Global Change Research Program.
1 2 Sims, J.; Saarinen, T. (1969). "Coping with Environmental Threat: Great Plains Farmers and the Sudden Storm". Annals of the Association of American Geographers. 59 (4): 677–686. doi:10.1111/j.1467-8306.1969.tb01806.x.
↑ Tarleton State University. "Grassland Slides". Archived from the original on 1 August 2016. Retrieved 14 March 2013.
↑ Moquet, N.; Gravel, D.; Massol, F.; Calcagno, V.; Blasius, B. (2013). Blasius, Bernd (ed.). "Extending the concept of keystone species to communities and ecosystems". Ecology Letters. 16 (1): 1–8. doi:10.1111/ele.12014. PMID23062191.
1 2 Freese, Curtis H.; etal. (2007). "Second Chance for the Plains Bison". Biological Conservation. 136 (2): 175–184. doi:10.1016/j.biocon.2006.11.019.
1 2 Knapp, Alan K.; etal. (1999). "The Keystone Role of Bison in North American Tallgrass Prairie". BioScience. 49 (1): 39–50. doi:10.2307/1313492. JSTOR1313492.
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