Grassland ecosystem is known to occur naturally on all the continents excluding Antarctica. It has been established that grassland ecosystem covers approximately 16 % of the total Earth’s surface (Crossman, et al., 2012). Grassland ecosystem is one of the terrestrial ecosystems that occurs in the areas where there is no enough precipitation to support the establishment of the forest, but enough rainfall to support growth of grass and prevent the formation of a desert. In addition, poor quality and low depth of soil prevent the growth of shrubs and other large trees.
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The structure of grassland ecosystem
Grassland is characterized by seasonal changes where the grass grow abundantly when rainfall is high and dormancy phase where the grass dries up due to low rainfall. The growth of grass is aided by the root stock and seeds deposited in the previous year (Crossman, et al., 2012). The seasonal changes observed in the grassland ecosystem have made the grasses and herbs as well as several species of mammals, birds and insects to evolve and adapted to wide-open grass covered areas. These species have developed mechanism of enabling them to thrive in these conditions where there is plenty of food during high rains and fat reservoirs that would be needed in the dry season when food is limited.
One example of grassland ecosystem is the Himalayan pasture belt, which extends up to the snowline. Himalayan pasture belt grassland ecosystem is essential since it supports wildlife that utilizes both forested and grassland. At the lower level, this grassland ecosystem is characterized by patches along with broadleaved or coniferous forests (Carlier, et al., 2009). In the summer, wildlife in Himalayan pasture belt migrates up into the high altitude grasslands and during winter they move downwards into the forested area since the snow covers the grassland. Himalayan pasture belt is habited by variety of herbs and grasses, while the hill slopes have plenty of colorful flowering plants.
Biotic and abiotic components of grassland ecosystem
All the living organism existing in the grassland ecosystem are known as biotic components. Biotic components are classified into producers and consumers or decomposers. Producers include cyanobacteria, lichens, mosses, trees, shrubs and grasses while consumers include herbivores such as grazers, omnivores such black bear, carnivores such as red-tailed hawk, vultures and rattle snakes and decomposers such as insects, some bacteria, algae and fungi (Leitinger, et al., 2015). Abiotic components are non-living features that supports living organism existing in grassland ecosystem. The four major abiotic components playing crucial role in grassland ecosystem are: natural disturbances, topography, soil and parent materials as well as climate. Each of these abiotic components influences the growth of plants, which in turn impact the live of animals inhabiting the grassland ecosystem. For instance, climate comprises wind patterns, temperature and rainfall which are the most important abiotic components in grassland ecosystem.
The functions of grassland ecosystem
Grassland ecosystem serve different function which include food supply for ruminants, genetic development, amenity purposes, grass as energy and fuel crop as well as grass for carbon sequestration and for charcoal. Many grassland ecosystems are used by pastoral communities to graze their livestock. In addition, grassland serves as rangeland which a primary resource dependent upon by the domestic and wild herbivores (Carlier, et al., 2009). Grassland ecosystem also provide better environment for research and the development of genetics and new varieties that have betters adaptation to the abiotic and biotic stress situations such as climate and diseases. Interspecific crossing of grass species in grassland ecosystems has led to development of tetraploid varies that have characteristics that are better suited to the environmental conditions experienced in grassland ecosystem. In some regions, grassland ecosystem are conserved for amenity purpose without any agricultural activities taking place.
The grassland ecosystems are reserved for lawns and parks. In other countries grassland is reserved as sporting field or open areas with different species of grass growing. Specific grass species are grown and breed so that they give a dense green appearance that make the field more attractive (Bahn, et al., 2014). For sporting field, the grass species that are known to be smooth in texture are chosen in order to facilitate the ease movement of ball and players. Some of the developed countries have turn the grassland fields to produce ornamental plants such as azaleas roses for commercial purposes.
Grassland ecosystem also provides grass as energy and fuel crop. Due to climate change, the demand for biofuel is increasing as compared to fossil fuel which is harmful to the environment. Studies have indicated that grassland is used to grow plants that are efficient in transferring biomass production into bio energy. Plants such as wheat straw, perennial grass species, willow and poplar are common in grassland ecosystem since they are known to be more productive for generation of second generation fuel (Carlier, et al., 2009). Another important function that make grassland ecosystem to be very significant is the ability to store carbon and serve as a carbon sink. In comparison with arable farm land, grassland have the capability to sequester almost double the quantity of carbon. Cumulatively, these functions make the grassland ecosystem a very important for both abiotic and biotic components.
Biogeochemical cycles is defined as the movement of nutrient elements through the various components of an ecosystem. Biogeochemical cycles occurs in two types: gaseous and sedimentary. For example, carbon cycle is one of the biogeochemical cycle in the ecosystem. Carbon is an organic compound that occurs in both abiotic and biotic components of the ecosystem. While carbon serves as building blocks of animal and plant tissues, it occurs as carbon dioxide in the atmosphere (Bahn, et al., 2014). Through a process of photosynthesis, plants are able to take in carbon dioxide from the atmosphere and combine it water observed from the roots to form a carbohydrates. In the process the plant releases oxygen into the atmosphere where the animals depends on for respiration process. Therefore, it clear that plants control and monitor the amount of carbon dioxide and oxygen in the atmosphere. In turn herbivores feed on plant material, which provide them with energy needed for growth. During respiration, animals and plants releases carbon dioxide. In addition, plants and animals fixes carbon in the soil, since they return carbon to the soil when they die. These processes form a carbon cycle.
Disturbance and recovery
Disturbance in grassland ecosystem occurs in two type: natural and man-made. Natural disturbance occurs through a process of drought and invasion by alien plants. Man-made disturbance comes as a result of overgrazing and burning of vegetation (Leitinger, et al., 2015). Due to climate change, persistent drought make grassland to lose most of the vegetation. Also, keeping excess animals than the carrying capacity leads to overgrazing. These two factors damages the grassland ecosystem because most of the vegetation is removed. The grassland recovers from the drought when the rains resumes.