Primary Succession: Stages, Examples, Importance

A natural community can change over time and get replaced by another due to several disruptions in nature. This process of successional change is called ecological succession. Ecological succession is the gradual and sequential development of a group of species over a long time, ranging from decades to millions of years.

There are two main kinds of ecological succession – primary and secondary. While both involve the development of species in a specific habitat, they vary in the ecological history and origin of the habitat.

Primary succession is a natural ecological process that occurs in environments where severe disturbances have left landscapes barren and devoid of life. The process of primary succession involves the step-by-step development of communities on newly exposed substrates, driven by the interactions among colonizing plants, animals, and soil microbes.

This phenomenon is particularly observed in areas that have experienced severe disturbances, such as volcanic eruptions, landslides, mining activities, or even in aquatic environments with newly exposed rocks, reefs, and shorelines. Understanding primary succession is essential for dealing with problems like the recovery of plants and animals, along with soil development, after major disruptions in nature.

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What is a Primary Succession?

Primary succession is a type of ecological succession that takes place in a barren and lifeless habitat, resulting in the development of a stable ecosystem.

This type of ecological succession occurs in areas without soil and living organisms, such as new volcanic islands or bare rocks. Over time, these areas turn into lively and thriving environments with plants and animals.
This process involves the gradual development of a biological community over time, starting with pioneer species that develop the initial biological environment and completing with a climax community.
The process usually begins with the arrival of pioneer species, which are often capable of quickly reproducing and colonizing the barren area. They contribute organic matter as they grow, die, and decompose. The organic matter creates pockets of soil, providing substrates for the growth of other plants and organisms.
Improved conditions lead to the growth of shrubs, small trees, and eventually larger trees, creating a complex web of interactions between different species.
Over time, the initially simple biological community evolves into a more complex structure as new species inhabit it.
The outcome of primary succession is the establishment of a stable and diverse ecological community in a previously lifeless or disturbed environment.

Stages of Primary Succession

Primary succession occurs in multiple stages, transitioning from the pioneer and intermediate species to a stable community. This change from a barren, lifeless area to a lively environment can take a long time, depending on the habitat conditions and the species characteristics.

The stages of primary succession are explained below:

Barren land: Primary succession takes place in an environment that has never sustained complex life forms. Common settings for primary succession include surfaces like bare rock, lava, or sand that lack nutrient-rich soil, making them initially unsuitable for the survival of plants and animals. While primary succession predominantly occurs on land, it can also take place in oceanic regions where lava has reached.
Pioneer species: The barren land is initially colonized by pioneer species. Pioneer species, along with abiotic factors like wind and water, play a vital role in breaking down rocks and increasing nutrient levels for the survival of other species. Lichens, moss, algae, fungi, and coral are examples of pioneer species. These organisms are adapted to grow on rocks and exposed land, thriving in harsh conditions.
Annual herbaceous plants: As pioneer species die and decompose, they create organic material that creates pockets of soil, allowing for the emergence of annual herbaceous plants such as ferns, grasses, and herbs. During this stage, small animals and insects also start colonizing the ecosystem.
Perennial herbaceous plants: As soil formation progresses, more plants and animals thrive and complete life cycles, improving soil quality. Bigger plants like perennials begin to thrive in this stage.
Shrubs: As the soil gets thicker and richer, it can support larger plants like shrubs. Shrubs start growing when the ground can support their root systems. These shrubs serve as a resource for animals, offering both food and shelter. Animals contribute to the ecosystem by transporting these shrubs and perennial seeds.
Shade-Intolerant Trees: Then, the initial trees start appearing in this stage. They lack shelter from the sun and are typically short, showing tolerance to wind and extreme temperatures.
Shade-Tolerant Trees: Trees and plants that prefer shade dominate the ecosystem in this stage. These trees replace and surpass some of the shade-intolerant trees, supporting a diverse range of plants and animals.
Climax Community: This is the final and ultimate stage in the process of primary succession. It is characterized by stability and high species diversity. This stage represents the completion of primary succession.

Disturbances Initiating Primary Succession

Primary succession can be triggered by various events, both natural and anthropogenic (manmade).
Examples of events that can initiate primary succession include volcanic eruptions, glacier retreats, flooding with severe soil erosion, landslides, nuclear explosions, oil spills, and the abandonment of manmade structures such as paved parking lots.
These events create conditions where the soil is absent or severely disturbed, allowing primary succession to occur.
Earth movements, such as earthquakes, volcanic eruptions, and landslides, expose barren substrates, setting the stage for primary succession.
Landslides and gradual soil erosion, both natural and human-induced through activities like overgrazing, contribute to barren substrates suitable for primary succession.
Hurricanes can uproot trees and expose mineral soil, facilitating primary succession. Hurricanes disrupt vast areas through wind damage, flooding, and erosion.

Examples of Primary Succession

Surtsey is a volcanic island off the coast of Iceland that emerged from the sea in 1963 due to a volcanic eruption. Scientists have closely monitored the colonization of this new land, observing the establishment of various plant and animal species over the years. Around 30 different plant species had successfully colonized this newly formed land by 2008.
The retreat of glaciers on Signy Island exposed new land, initiating primary succession. Lichens were among the pioneer species that colonized the barren area, and over time, more complex plant and animal communities were established.
The volcanic eruption of Mount St. Helens in 1980 caused widespread destruction of vegetation and landscapes. Researchers have studied the primary succession that followed the eruption, observing the gradual recovery of plant and animal communities.
The eruption of Krakatoa in 1883 devastated the island, creating a barren landscape. Scientists have studied the subsequent primary succession on Krakatoa, observing the colonization of new species and the development of ecosystems.
Areas affected by mining activities, where topsoil has been removed, serve as an example of primary succession. Researchers analyze how vegetation and ecosystems recover in these disturbed environments.

Importance of Primary Succession

The diverse habitats formed through primary succession create more resilient ecosystems to environmental changes. Diverse habitats support a wide range of plants, animals, and microorganisms, contributing to the overall ecological balance.
Pioneer species break down rocks and organic material, contributing to soil development and enriching the soil with essential minerals and nutrients.
The vegetation during primary succession also helps in preventing soil erosion. Plant roots stabilize the soil, minimizing the risk of soil erosion from wind and water.
The established vegetation in the climax community stores carbon over the long term. This process contributes to mitigating climate change.
Ecosystems resulting from primary succession also offer recreational spaces for humans. The diverse ecosystem contributes to the aesthetic value of natural landscapes.

References

Biologydictionary.net Editors. (2016, October 27). Primary Succession. Retrieved from https://biologydictionary.net/primary-succession/
Del Moral, R., & Titus, J. H. (2018). Primary Succession on Mount St. Helens: Rates, Determinism, and Alternative States. Ecological Responses at Mount St. Helens: Revisited 35 Years after the 1980 Eruption, 127–148. https://doi.org/10.1007/978-1-4939-7451-1_7
Helmenstine, A. M. (2021, September 8). Primary Succession Definition and Examples. Retrieved from https://www.thoughtco.com/primary-succession-definition-and-examples-4788332
Helmenstine, A. M. (2023, October 31). Primary Succession Definition and Examples. Retrieved from https://sciencenotes.org/primary-succession-definition-and-examples/
Primary succession | Definition, Stages, & Facts | Britannica
Walker, L. R., & Del Moral, R. (2003). Primary succession and ecosystem rehabilitation. Cambridge University Press.
Walker, L. R., & Del Moral, R. (2011). Primary succession. eLS. John Wiley & Sons, Ltd: Chichester. DOI: 10.1002/9780470015902.a0003181.pub2