Introduction
An ecosystem is the most important component for the existence of the earth. It consists of different types of biotic and abiotic components. Biotic components are the living things in the ecosystem. Abiotic components are the non-living features in the ecosystem like climate, natural disturbances like a flood, heavy rain, high temperature, etc. Soil is the critical linking factor between these biotic and abiotic components in the ecosystem (Abiotic components, 2009).
Biotic components in the local ecosystem
Biotic components are classifieds into two types. They are producers and consumers, or decomposers. Producers accept energy from the sunlight and nutrition from the soil. Consumers may not accept energy from sunlight, so they get energy from plants and animals. These consumers are again divided into three types and this classification is done based on their digesting ability. Those three types are herbivores which eat only plants, omnivores which consume both plants and animals and the third type is carnivores which choose only animals as their food. Insects, fungi, bacteria, etc. are included in the decomposers group. (Biotic components, 2009).
Based on the nature of the soil and climate, the living things in the biotic system may vary from one ecosystem to another. That is, animals, plants, and microorganisms in one local ecosystem may not be able to survive in another local ecosystem. The following data gives lists of components seen in the local ecosystem.
Producers seen in the local ecosystem are grasses, trees, and mosses.
Major herbivores seen in the local ecosystem are deer, sheep, horses, parrots, and rabbits.
Major omnivores seen in the local ecosystem are human beings and chickens.
Carnivores seen in the local ecosystem are wolves, dogs, and eagles.
The main insects found here are termites, cricket, mosquitoes, etc.
Ecosystem succession
An ecosystem is the combination of biotic or living organisms and abiotic or non-living things that form an environment. Ecological succession refers to the changes that take place in an ecosystem. Succession can happen in two ways. One is due to the formation of a new habitat where the soil is new and organisms have not thrived before. This is called primary succession and is mainly a work of natural calamities like a severe landslide, lava flow, etc. (Ecological succession, n.d.).
Secondary succession is the other kind of succession. Here the soil is not new and is caused by disturbances such as a fire, hurricane, etc that destroy the existing vegetation. (Ecological succession, n.d.).
Primary succession on glacial moraine
Glacial moraine is the materials like rock and soil that get transported and deposited by a glacier. Six types of recognizable landforms are formed due to glacier deposition and there are other two types that are formed on top of the glacial ice. (Glacial moraine, 2006).
Other than the glacier depositions, the moraines will have sand dunes that are deposited by the wind and water. Due to the extreme nature of sand dunes and the deficiency of essential minerals, not all plants can survive here. Lichens are the first species that grow mainly on rocks and barren land. They fix the nitrogen content of the soil, making it more suitable for plant growth. Grasses are the common plants that grow on sand dunes. The root holds the soil and prevents erosion. These are followed by mosses and small shrubs which stabilize the dunes. With the passage of years, poplars or cottonwoods thrive in this region, which is later dominated by pines and oaks. This type of vegetation change occurs due to the replacement of one group by the same or different species. The property of the plants and their interaction with the environment leads to the growth of more variety. This is a very complex system, involving the living systems and their interrelationships with the inorganic components and the process of energy and nutrient production. The soil fertility in such regions remains very low, so rarely do the forest trees replace oaks.
Secondary succession
Secondary succession takes place in regions where the vegetation was destroyed once in all or some regions of the community. This can be caused by humans, animals, wind, water, fire, or similar forces. Secondary succession is faster due to the richer and more fertile soil, and the presence of seeds or stems from the previous system.
Studies conducted in Yellowstone National Park where a forest fire had once destroyed the vegetation showed that the ground was initially covered by ash. The trees were charred and dead. But the secondary succession in such regions took over rapidly. In less than a year, trout lily and other herbs covered the ground. After about a timeframe of ten years, a young forest of lodgepole pines had dominated the area and Douglas fir seedlings were also present. (Raven, Berg & Hassenzahl, n.d.).
Studies were done on the secondary succession on abandoned farmland in North Carolina. A year after cultivation is stopped, crabgrass dominates the region. During the second year, crabgrass is dominated by a larger variety called horseweed. The decaying roots of the horseweed inhibit the growth of young horseweed saplings. Also, other plants that are more dominant get established in the third year. Other weeds like broomsedge, ragweed, and aster replace horseweed. Broomsedge is more competent than aster because of its property of being drought-tolerant. (Raven, Berg & Hassenzahl, n.d.).
The organisms living in the soil play a major role in changing the properties of the soil. The major changes are in the accumulation of organic matter, nutrient content, and the pH level of the soil. Animals also play a major role as they act as seed disposers. They help in pollination and can also increase the nutrient content of the soil, mainly due to their excreta. Some insects and animals like termites, ants, and moles move the soil to a small extent. These areas may be preferred by certain varieties.
The structure of the plants can also cause changes in the environment. Initially when there are fewer plants and the sunlight is more, plants intolerant of shade dominate the region. With the growth of more plants, more shade is produced and hence these plants are replaced by shade-tolerant species. Climatic factors also play a major role in successional changes.
In an abandoned field, during a period of the first 5 to 15 years, pine saplings are the dominant plants, such as shortleaf pines and loblolly pines. During the next 25 to 50 years, a young pine forest is developed in this region. Pines produce environmental changes. Hence, in about a century, pines are replaced by hardwoods such as oaks. Pine litter results in soil changes, increasing the water holding capacity of the soil. Young oak seeds cannot grow in this kind of soil. Also, pine seeds require less shade when compared to hardwood seedlings and with the growth of each plant, more and more shade is produced. Due to these changes in the environment, hardwood such as oaks, hickory, etc dominates over the previous pine vegetations. This is the process of secondary succession that takes place in abandoned farmland.
Comparing and contrasting the findings
Primary succession is a slow process because the soil is new and there were no previous forms of life in that region. But, comparatively, secondary succession is a more rapid process and the soil is not new. Both biotic and abiotic components contribute to the changes that take place in an environment. Biotic or living organisms such as animals act as seed disposers and also help increase the nutrient content of the soil. The organisms that live in the soil increase the nutrient content and change the pH level. Plants also play a major role in changing the ecosystem. Each species supports the growth of another variety by providing favorable conditions. In this way, every element interacts with each other leading to the evolvement of ecology. Studies conducted in Yellowstone National Park and abandoned farmland in North Carolina show the mechanisms that take place during the process of recovery of an ecosystem, after a disturbance.
Conclusion
Nature has its own ways of recovering and re-establishing its environment, after subsequent damage. A newly formed land will also undergo changes due to the process of succession.
References
- Abiotic components. (2009). Grasslands Conservation Council of British Columbia.
- Biotic components. (2009). Grasslands Conservation Council of British Columbia.
- Ecological succession. (n.d.). Biology 100/101: Lecture 5: Ecosystems in Time (Succession).
- Glacial moraine. (2006). The Geography Site. Web.
- Raven, P., Berg, L., & Hassenzahl, D. (n.d). Environment. 6th edition. (Provided by the customer).