Secondary Succession: Stages, Examples, Importance

Communities contain groups of living organisms in specific places. Over time, these groups change driven by the process of succession. This change in community is important to understand because they have a big impact on how we manage and take care of these natural communities.

Succession is the sequential change in the species of a community. Ecological succession can be defined as the gradual change in the composition of a biological community that starts from one point and gradually transforms the community as various species enter and exit. These changes happen slowly, taking a long time, leading the community towards a more stable condition known as a climax. 

Secondary succession is one of the types of ecological succession that occurs when a community of different species changes following a disturbance or damage to its habitat.

Secondary succession can be defined as the process of re-establishing a complete ecological community using the remaining soil after an ecological disturbance.

In contrast to primary succession, which occurs on a barren landscape where life never existed, secondary succession takes place in areas where not everything is wiped out, and some nutrients and living things remain. 

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What is Secondary Succession?

Secondary succession is a type of ecological succession that occurs in places disturbed by major events like floods, landslides, or human activities but is not entirely devoid of life. In this process of succession, plants and animals re-establish themselves in the destroyed ecosystem.

  • Even though events like fire or floods may cause visible damage and revert the biological community to the previous stage, the soil still contains nutrients from before the disturbance. 
  • The key difference between secondary succession and primary succession is that secondary succession involves some existing remnants of soil, whereas primary succession begins on the ground without any soil precursors.
  • Secondary succession involves less competition for resources compared to primary succession. Unlike primary succession, which starts with a scarcity of resources, secondary succession starts with ample resource availability.
  • The primary sources of energy for plants in this ecological process come from existing remnants in the soil, including decomposed organic material, inorganic salts, humus, and more.
  • Secondary succession always follows after primary succession has taken place. The presence of a remnant substrate or precursor is important for the initiation of secondary succession.
  • Secondary succession takes a shorter time than primary succession because soil, nutrients, and other biotic organisms are already present within the substrate.

Stages of Secondary Succession

The stages involved in the process of secondary succession are similar to the stages of primary succession. It starts with pioneer species coming into the cleared area, and over many years, they make way for a community of intermediate species, and finally a stable climax community form.

Secondary Succession
  1. Disturbance: The process begins with a disturbance that disrupts the existing ecosystem and creates an opening for new species to colonize the area. Disturbances can be natural, such as wildfires, floods, or volcanic eruptions, or human-induced, like deforestation or agricultural activities.
  2. Pioneer species: Following a disturbance, pioneer species are the first organisms to colonize the damaged landscape. These species are hardy and fast-growing organisms, like lichen, moss, native spreading grasses, and small herbaceous plants, which thrive in environments with abundant sunlight. They have simple nutritional needs and can convert the substrate into soil and nutrients, making it available for other organisms. These plants are frequently already present as seeds in the soil or can quickly spread from nearby locations.
  3. Intermediate species: Pioneer species are gradually replaced by intermediate species, such as perennial herbaceous plants, shrubs, short-lived annual plants, and softwood trees like pine. They are slower-growing plants. These organisms continue the process of ecological transformation, further modifying the soil composition and structure of the environment. 
  4. Climax community: The last stage is the climax community, where a more stable and mature ecosystem is established. In a climax community, the environment can sustain larger, more complex organisms and it indicates ecological equilibrium. Species in this stage, like oak and hickory trees, are adapted to thrive in the mature and stable environment created during this stage. In a climax community, species are stable and no longer being replaced, reflecting a state of balance as seen in mature forest communities. They remain stable and can last until the next ecological disturbance arrives. 

Disturbances That Cause Secondary Succession

Disturbances that cause secondary succession include natural disasters like wildfires, floods, and hurricanes. Human disturbances such as deforestation and urban development are also disturbances leading to secondary succession.

Some common disturbances that lead to secondary succession include:

  • Fire is one of the common causes of secondary succession. Wildfires can clear large areas of vegetation, creating an environment for new growth to emerge. 
  • Events such as floods and landslides can disturb soil and vegetation, creating conditions for new plant and animal species to establish themselves.
  • Hurricanes and storms can uproot trees and damage vegetation, initiating secondary succession.
  • Anthropogenic or human activities such as deforestation, agriculture, and urban development can significantly disrupt ecosystems, leading to secondary succession.
  • The spread of diseases affecting plant or animal populations can also lead to the decline or loss of species, creating opportunities for new species to establish themselves.
  • The abandonment of agricultural land is another cause of secondary succession. When these lands are abandoned, it provides an opportunity for new vegetation to recolonize the area. 

Examples of Secondary Succession

  • In 1988, the wildfires in Yellowstone National Park resulted in extensive damage. Following the fires, the affected areas experienced secondary succession, with the re-establishment of vegetation. Early successional plants like Pinus contorta, Pseudotsuga menziesii var. glauca, and Populus tremuloides played a big role in reviving the ecosystem. 
  • In old field succession in the Piedmont of North Carolina, abandoned fields undergo secondary succession. Initially, crabgrasses and horseweeds dominate the first year of abandonment. By the second year, aster becomes the main plant in the fields. Broomsedge becomes the dominant plant in the third year until it is replaced by young pine trees. Then, big trees called hardwoods take over becoming the main trees in the area. Periodic disturbances, such as fires every 5–7 years help to keep the young pine trees around and stop the complete dominion of hardwood trees. 
  • In East Kalimantan, Indonesia, secondary succession occurs in Imperata grasslands due to human activities like logging, farming, grazing, and intentional fires. When these disturbances cease and the grasslands are no longer regularly burned, pioneer species like ferns, herbs, and young trees rapidly colonize the area, eventually leading to the transition from Imperata grassland to secondary forest.
  • Secondary succession occurs in oak and hickory forests following a wildfire. After severe fires clear the landscape, the nutrient-rich ashes provide fertile conditions leading to the dominance of annual plants and pioneer species. As the pioneer species establish themselves, the environment changes, allowing intermediate species like shrubs, small trees, oak, and hickory to emerge. The process ends in a stable climax community, maintaining equilibrium until the next disturbance.

Importance of Secondary Succession

  • Secondary succession allows ecosystems to recover and restore biodiversity after disturbances like wildfires, floods, or human activities. 
  • As different plant and animal species recolonize, it also enhances the overall diversity and complexity of the ecosystem.
  • Secondary succession often occurs more rapidly than primary succession. Since soil and some remnants are already present, the recovery process can be faster.
  • Secondary succession is often caused by human-induced disturbances, such as deforestation, or urban development. Understanding the process of secondary succession is important in managing landscapes changed by such human activities.

References

  1. Antoniadou, C., Voultsiadou, E., & Chintiroglou, C.-C. (2019). Succession and Colonization. Encyclopedia of Ecology, 369–378. https://doi.org/10.1016/B978-0-12-409548-9.10594-9
  2. Biologydictionary.net Editors. (2016, November 10). Secondary Succession. Retrieved from https://biologydictionary.net/secondary-succession/
  3. Ecological succession | Definition & Facts | Britannica
  4. Keever, C. (1950). Causes of Succession on Old Fields of the Piedmont, North Carolina. Ecological Monographs, 20(3), 229–250. doi:10.2307/1948582
  5. Neal, Emily. (2019, November 22). Steps of Primary & Secondary Succession. sciencing.com. Retrieved from https://sciencing.com/steps-primary-secondary-succession-7248745.html
  6. Rye, C., Wise, R., Jurukovski, V., DeSaix, J., Choi, J., Avissar, Y. (2016). Biology. OpenStax. Retrieved from https://openstax.org/books/biology/pages/45-6-community-ecology
  7. Secondary succession – Definition and Examples – Biology Online Dictionary
  8. Secondary succession | Definition, Stages, & Facts | Britannica
  9. What is ecological succession? | University of Chicago News (uchicago.edu)
  10. Yassir, I., van der Kamp, J., & Buurman, P. (2010). Secondary succession after fire in Imperata grasslands of East Kalimantan, Indonesia. Agriculture, Ecosystems & Environment, 137(1-2), 172–182. doi:10.1016/j.agee.2010.02.001

About Author

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Sanju Tamang

Sanju Tamang completed her Bachelor's (B.Tech) in Biotechnology from Kantipur Valley College, Lalitpur, Nepal. She is interested in genetics, microbiome, and their roles in human health. She is keen to learn more about biological technologies that improve human health and quality of life.

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