Ecological Succession: Definition, Types, Examples, Facts, Characteristics

Ecological succession is the gradual development and change of species and communities in an ecosystem; it is an extremely fundamental process in ecology.

Definition Of Ecological Succession

Ecological succession refers to the amount of subsequent, orderly process whereby ecosystems make changes across time from bare or disturbed environments into stable, mature ecosystems. It involves the gradual colonisation of species, establishment of communities, and interaction of the organisms with the environment. There are two forms of this process: primary succession, which starts in an entirely new habitat lacking soil and vegetation, and secondary succession, which takes place in areas where an existing community has been disturbed or destroyed but the soil remains.

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This Story also Contains

1. Definition Of Ecological Succession
2. Types Of Ecological Succession
3. Examples Of Ecological Succession
4. Factors Influencing Ecological Succession
5. Ecological Succession And Ecosystem Services

Ecological succession is important in appreciating very well the evolution of an ecosystem to changes in the environment. Succession plays a significant role in the dynamics of ecosystems as it helps give biodiversity, enhances resilience, and promotes nutrient turnover. Through succession, it is possible to make several inferences about the behaviour an ecosystem can face in the case of perturbation through events such as natural disasters or man-induced activities, hence conserving endeavours and management strategies of ecosystems aimed at conserving biodiversity and functions.

Types Of Ecological Succession

The different types of ecological succession are:

Primary Succession

Primary succession takes place in areas where the soil is completely absent at the beginning, for instance, on bare rock or land exposed by retreating glaciers or volcanic eruptions. Primary succession is initiated by pioneer species, which constitute the first category of living things that colonise these areas, which tend to be inhospitable. These types of species, mainly comprising lichens and mosses, are tolerant of harsh conditions and, via physical and chemical means, start the rock breakdown into the soil. These pilot species eventually die and decompose, adding organic matter to the developing soil, thus allowing more diverse plant communities to become established. For example, lava flows following a volcanic eruption or after the retreat of glaciers when bare rock is exposed.

Secondary Succession

Secondary succession is the type of succession that occurs in an already existing but disturbed or disrupted ecosystem where the soil and seeds for plants are intact. It happens more rapidly than primary succession as, here, the soil itself contains many nutrients and seed sources. This kind of transition may happen after forest fires, abandoned agricultural land, or areas that have been swept away by hurricane-force winds. Compared with primary succession, starting with bare surroundings can result in the fairly swift re-establishment of plant and animal communities. Indeed, the series of species that constitutes secondary succession is generally quite predictable and usually comprises a series of stages from fast-growing species to the final stages, which lead to more stable diverse communities.

Cyclic Succession

Cyclic succession, also known as seasonal succession, is a repeated, predictable pattern of succession taking place over shorter timescales within specific ecosystems. This is driven by seasonal changes in abiotic environmental conditions, such as temperature, precipitation, and sunlight. Thus, the plant communities in temperate regions may undergo cyclic succession, where different species dominate throughout spring, summer, autumn, and winter. This type of succession does not involve drastic changes in the structure of the ecosystem but rather involves changes in dominant species under seasonal variation.

Seral Community

Seral community succession, also known as linear succession, is a progression of communities where one stage makes the environment suitable for the next in a development leading to a climax. It is relatively common, especially in an aquatic environment, such as fish ponds or in any lake during eutrophication. First, it is dominated by pioneer species like algae and floating plants, succeeded by submerged aquatic vegetation, and finally by terrestrial plants and shrubs. With every stage that the process goes through, the habitat is modified in such a way that it becomes more favourable for the establishment of the succeeding community. In other words, there is a net progression towards a more stable ecosystem state.

Examples Of Ecological Succession

Examples of ecological succession are:

Volcanic Eruption

Following the catastrophic eruption of Mount St. Helens in 1980, primary succession began immediately in the denuded landscape. The first to take over volcanic rock and ash were pioneer species such as lichens and mosses. After a couple of decades, the early colonizers died off and started building up some soil, which supported more complex plants like grasses and herbaceous species. By the 2000s, young coniferous trees like lodgepole pine and western hemlock began to dominate, gradually building a forested ecosystem out of the landscape. This succession timeline exemplifies nature's incredible ability to regenerate and rebuild after catastrophes.

Pond Ecosystem

One of the very impressive examples of ecological succession is the succession of a pond or lake ecosystem. Initially, almost every newly formed pond is colonized by algae and floating plants like duckweed. Sometime after this accumulation of organic matter and some sedimentation, emergent plants such as reeds and cattails may take hold along the edges. This makes the pond a marsh or wetland habitat. Over time, once more filled in with organic material and sediment, shrubs and small trees may establish themselves, which can then more fully transition the ecosystem into a wooded wetland or swamp. This, therefore, shows the progress of succession from open water to a diverse mature wetland ecosystem.

Factors Influencing Ecological Succession

Succession is determined by a mixture of biological and physical properties.

Biological Factors: Competitive reasons related to species, which include competing for the same resources, like light and nutrients, are some of the reasons for community composition. Predation and symbiotic relationships, as in mycorrhizal association, affect population dynamics and nutrient cycling. If species diversity increases over some time, it guarantees an increase in ecosystem complexity and resilience.

Physical Factors: The physical factors, such as climate, determine the species that may be favoured to occupy a particular area at any given time of the different succession stages. Soil characteristics, like pH and texture, ensure the availability of nutrients and water to plants for growth and establishment of plant communities. Other perturbations, such as fires or human activities added to these, may reset succession and thus alter community trajectories and diversity over time.

Ecological Succession And Ecosystem Services

Ecological succession is important for the maintenance of biodiversity in that it allows for an increase in habitat diversity and the varied existence of species. Succession thus confers resiliency against disturbance, increases productivity, and creates complex pathways of interactions and nutrient cycling. It is essential in sustaining healthy ecosystems that have inherent benefits such as habitat provision, water purification, and climate control.

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