Biotic and Abiotic Description:

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Grasslands are areas where the vegetation is dominated by grasses and non-woody plants. There are six different types of grasslands in the world. Tropical and Subtropical Grassland,Temperate Grassland, Flooded Grassland, Montane Grassland, Tundra Grassland, and Desert and xeric grasslands.

Tropical and subtropical grasslands are classified with tropical and subtropical savannas. Notable tropical and subtropical grasslands include the Llanos grasslands of northern South America. Temperate Grasslands are mid-latitude grasslands. Temperate grasslands are the home to many large herbivores, such as bison, gazelles, zebras, rhinos, and wild horses. Carnivores like lions, wolves, cheetahs, and leopards. Other animals include: deer, prairie dogs, mice, jack rabbits, skunks, coyotes, snakes, fox, owls, badgers, blackbirds, grasshoppers, meadowlarks, sparrows, quails, hawks, and hyenas. Flooded Grassland are flooded seasonally or year-round, like the Everglades of Florida. They are classified with flooded savannas as the flooded grasslands and savanna biome and occur mostly in the tropics and subtropics. Montane Grassland are high-altitude grasslands located on high mountain ranges around the world, like the Paramo of the Andes Mountains. They are part of the montane grasslands and scrublands and also constitute tundra. Tundra Grasslands are similar to montane grasslands, polar arctic tundra can have grasses, but high soil moisture means that few tundras are grass-dominated today. Finally, Desert and xeric grassland is composed of sparse grassland eco-regions located in the biome.

Climate:


Grasslands occur naturally on all continents except Antarctica, In temperate latitudes, such as northwestern Europe and the Great Plains, and California in North America. Natural grasslands primarily occur in regions that receive between 9.8 and 35 in of rain per year, as compared with deserts, which receive less than 9.8 in and tropical rain forests, which receive more than79 in. Grassland can exist naturally in areas with higher rainfall. Average daily temperatures range between -20 and 30 °C. Temperate grasslands have warm summers and cold winters with rain or some snow.
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Plants:


Grasslands dominated by unsown wild-plant communities ("unimproved grasslands") can be called either natural or 'semi-natural' habitats. The majority of grasslands in temperate climates are 'semi-natural'. Although their plant communities are natural, their maintenance depends upon anthropogenic activities such as low-intensity farming, which maintains these grasslands through grazing and cutting regimes. These grasslands contain many species of wild plants - grasses, sedges, rushes and herbs. The soil is extremely rich in organic material due to the fact that the
abovegroundof grasses die off annually, enriching the soil. Temperate Grassland Plant Adaptations include:
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  • During a fire, while aboveground portions of grasses may perish, the root portions survive to sprout again
  • Some prairie trees have thick bark to resist fire
  • Prairie shrubs readily re-sprout after a fire
  • Roots of prairie grasses extend deep into the ground to absorb as much moisture as they can
  • Extensive root systems prevent grazing animals from pulling roots out of the ground
  • Prairie grasses have narrow leaves while lose less water then broad leaves
  • Grasses grow from near their base, not from their tip, thus are not permanently damaged from grazing animals
  • Many grasses take advantage of exposed, windy conditions and are wind pollinated
  • Soft stems enable prairie grasses to bend in the wind, minimizes water loss

Animals:


a moderate level of species diversity can be seen in the grassland biome, and the adaptation skills of the animals found here have a crucial role in making sure that this biodiversity prevails. Over the period, these animals have adapted themselves to the seemingly harsh conditions that typically characterize this region. The fact that the animals from temperate grasslands have adapted themselves to the dry, windy conditions prevailing in this biome, is an apt example of animal adaptations in the grassland biome. There exist several other factors - including their size, diet, seasons, etc., all of which have a crucial role to play when it comes to their adaptation skills.

The size of these animals is one the most important factor in the grassland biome. While the small animals like insects, jack rabbits, snakes, Prairie dogs, etc., can easily hide in the tall grass that grows in this biome for protection against predators as well as for hunting, large animals are gifted with adaptations like camouflage and speed to facilitate the same. Furthermore, their size in itself is one of the best adaptations for large animals - like the African elephant and the rhinoceros, when it comes to self defense. Yet another defensive adaptation which is often seen in this biome is that of forming groups (herds). In fact, this is one of the apt defense strategies - which makes sure that even the young ones and injured individuals are safe from predators.

Other than their size, other physical characteristics and behavior also comes into play when it comes to protection. Some grassland animals are armed with strong front legs - with sharp claws which help them burrow in the ground wherein they are safe from large predators with whom they share their natural habitat. Camouflage is yet another adaptation that many grassland animals resort to when it comes to defense against predators. Similarly, quite a few animals of the Prairie grasslands are nocturnal in nature - which means they are active during the night. As in case of camouflage, even their nocturnal nature helps them to stay off the predator's radar.
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One of the best example of grassland animal adaptations in accordance with their dietary habit can be seen in bison species who sport flat-topped teeth which makes it easier for them to feed on grass. Studies have also revealed that the digestive system of a bison is well adapted for the digestion of grass. One also gets to see a great deal of diversity when it comes to the size of herbivorous animals found in grasslands. Their height plays a crucial role in ensuring that there is no competition for food in this biome - while small antelope species feed on grass and leaves of short plants, the giraffe feeds on leaves at a considerable height on the trees.

The Savannah grasslands of Africa are typically characterized by a great deal of variability when it comes to food supply - with food available in plenty during a part of the year, and severe food scarcity prevailing at other times. It's the amazing ability of the animals here to migrate thousands of miles from one part of the biome to another, which helps them survive this food crisis. On the other hand, the animals in Prairie grasslands of North America and Steppes of Eurasia have the ability to survive in extremely cold winters - with temperature falling below the freezing point at times, which is again a basic geographical feature of the temperate grasslands.

Competition and Cooperation:


One example of cooperation is the rhino and the oxpecker. In the relationship, the bird benefits from the free rides that it gets while riding on the back or on the head of the rhino. While the oxpecker rests on the rhino, it eats ticks and other harmful insects. This relationship is known as mutualism because both members benefit from the relationship.

Another example of cooperation in grasslands is a relationship between buffalo and mircoorganisms that live in one of their four stomachs. When the buffalo eat leaves and other plants, the mircoorganisms consume and process some of the fibers in the plant. But when they die, they become consumed by the buffalo's stomach and get turned into usable protein
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Invasive Species:


Non-native Invasive Species:
Mimosa is a plant species that is native to Asia that came to the United States in 1745. It thrives in disturbed habitats such as stream banks, old fields, and roadsides. Because of its difficulty to remove due to the long lived seeds and its ability to re-sprout vigorously, Mimosa had been able to spread itself around the United States.
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Another non-native invasive species to grasslands is the Japanese climbing fern. Native to Japan, the climbing fern came to the United States when imported around the 1930's. This plant's rapid growth can cause the occurance of mats which can smother smaller plants and shrubs. It's ability to rapidly reproduce is a result of easily-spread spores.
Invasive Species with the Same Trophic Level:

An invasive species that affects the same trophic level is the alligatorweed. The alligatorweed is notorious for its ability to grow roots that gravitate toward agents of water that cause difficulty for other plants to grow. The growth of the alligatorweed can displace native vegetation , clog waterways, alter oxygen levels of water, increase sedimentation, interfere with irrigation and prevent drainage. Originally native to South America, alligatorweed has caused problems with the growth of other plants as it has been introduced in North American ecosystems.

Another invasive species is one that is causing problems througout much of North America, the leafy spurge. This plant causes structural and functional problems to other plant species. Specifically, in addition to overcrowding its own trophic level due to not having natural predators, the leafy spurge creates strong filtering effects on plant species composition that can hinder the growth of other species of plants and thus obstruct species variety. This plant mostly appears in areas where extensive deforestation occured because it is quick to .

Invasive Species with other Trophic Levels:
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As a result of the in leafy spurge in North American grasslands, ecologists have introduced the Aphthona flea beetle to counteract its affects. It is hoped that by introducing the species of beetle, the population of the leafy spurge will be controlled to the point where it will not create a significant problem. The Aphthona flea beetle is a natural predator of the leafy spurge so introducing it to monitor the growth of a plant with otherwise few predators will likely be effective.

The saltcedar, an introduced species in the grasslands of Colorado, is introduced for the purpose of preventing erosion of the surrounding area so that the habitats and homes of animals and secondary consumers can be maintained. In this instance, the introduced species is benefitting the other.

Threatened and Endangered Species:


1) As the largest land animal, the African bush elephant reaches up to 24 feet in length and 13 feet in height. Also known as the African savanna elephant, it is found in most African countries, living in varied habitats from the open savanna to the desert and high rainforest. It is the largest of the three elephant species and can weigh up to 11 tons and live up to 70 years, longer than any other mammal except humans. African bush elephants are herbivores and need to eat about 350 pounds of vegetation daily. Because elephants require substantial amounts of food and a large area in which to forage, habitat destruction across their range is a major threat to survival. Hunting has caused the most serious damage to African bush elephant populations. Humans kill elephants primarily for their tusks, and the population was decimated to the point of extinction throughout the 19th and 20th centuries and is still considered highly threatened with extinction in several areas of its range.


2) The American Bison, The largest land mammal in North America, adult males may stand as tall as six feet at the shoulders and weigh 1000-2000 pounds. Bison are grazers, traveling between pastures in groups ranging from family units to large herds.
Once a staple for some Native Americans, millions of American bison roamed from Canada to Mexico and from New York to California, until wholesale slaughter by American settlers brought them to the brink of extinction in the early 20th century. At the end of the slaughter, less than 100 free-roaming bison remained in the world. Thanks in large part to the efforts of the American Bison Society, the species has rebounded, and herds have been built up in preserves, where they live in a semi-wild state. However, genetic diversity in a population bred from such reduced numbers remains a concern, especially since individuals mate with vastly different success rates, further limiting the available gene pool.
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Human Impact on the Grassland Biome:


Humans have had ranging impacts on grassland biomes. Those areas that are most affected by humans are normally used for agricultural purposes. For example, much of the grassland in North America has been used for farms and commercial agriculture. Humans clear the existing vegetation for their desired crop in some places, and in others, they leave the existing grass alone so that livestock can use it for food. Another impact humans have on grasslands is hunting. Many grassland animals, such as the bison, elephant, lion, and others, have been hunted for their respective rarities. Specifically, large numbers of lions have been hunted for their skins, elephants have been hunted for their tusks, and bison have been hunted for their meat. Some of these animals have been nearly hunted toward extinction.


Works Cited:


“Grasslands.” October 2000. 24 October 2011. http://www.blueplanetbiomes.org/grasslands.htm.

“Grasslands”. National Geographic. N.p. n.d. 24 October 2011. http://environment.nationalgeographic.com/environment/habitats/grassland-profile/.

“Mammals”. The Nature Conservancy. N.p. n.d. 25 October 2011. http://www.nature.org/newsfeatures/specialfeatures/animals/mammals/index.htm.

“The Grassland Biome.” California Academy of Science. N.p. n.d. 25 October 2011. http://www.ucmp.berkeley.edu/exhibits/biomes/grasslands.php

“The Grassland Biome(s).” Marietta College. N.p n.d. 30 October 2011. http://www.marietta.edu/~biol/biomes/grass.htm.