Ecological Succession: How Ecosystems Grow, Change, and Mature

The idea of ecological succession has its roots in the early 19th century. In 1825, French naturalist Adolphe Dureau de la Malle first introduced the term to explain how vegetation recovers after forests are cleared.

Later, in 1899, American ecologist Henry Chandler Cowles brought renewed attention to this concept through his doctoral research at the University of Chicago. While studying the sand dunes along the southern shore of Lake Michigan, Cowles observed how plant communities and soil developed together over time.

He described ecological succession as a gradual, step-by-step process in which ecosystems evolve from early, simple stages to more complex and stable forms. During this process, some species decline while others become more dominant, leading to continuous change within the ecosystem.

Located on the northeastern shore of the Big Island of Hawaii, Hi’ilawe Falls drops more than 1,400 feet down a steep cliffside of sacred Waipi’o Valley. The moss-covered lava rocks surrounding the waterfall exhibit primary succession.

The Climax Community Theory

Around the same time, another influential ecologist, Frederic Clements, expanded the concept further. Based on his studies in the grasslands of the western United States, Clements proposed that ecological succession follows a predictable and orderly path.

He compared ecosystem development to the growth of a living organism—starting from a simple beginning and progressing toward a fully developed, stable state known as the climax community. This idea became one of the most widely accepted theories in ecology throughout much of the 20th century.

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Types of Ecological Succession

Ecological succession can occur in different ways depending on the starting conditions of the environment. The two main types are primary succession and secondary succession.

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Primary Succession: Life Begins from Scratch

Primary succession occurs in areas where no life previously existed. These environments may include:

• Bare rocks
• Sandy surfaces
• Regions covered by lava after volcanic activity

In such harsh conditions, the first organisms to appear are known as pioneer species. These are usually simple organisms like:

• Lichens
• Mosses
• Grasses

These pioneers can survive with very few nutrients. They break down rock surfaces and help form soil, making the environment suitable for more complex plants.

Over time, the area develops further:

1. Small plants and grasses establish
2. Shrubs begin to grow
3. Trees take root
4. Animals enter the ecosystem

Eventually, this leads to a stable and fully developed ecosystem known as the climax community.

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Secondary Succession: Recovery After Disturbance

Secondary succession takes place in areas where life once existed but was disrupted. Common causes include:

• Forest fires
• Floods
• Hurricanes
• Human activities like logging or farming

Unlike primary succession, the soil in these areas is already present, which allows recovery to happen much faster.

Plants and organisms return in stages, gradually restoring the ecosystem. This process moves through a series of intermediate phases known as a sere, a term introduced by Cowles.

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How Succession Shapes Ecosystems

One of the most fascinating aspects of ecological succession is how each stage prepares the way for the next. As new plant species grow, they:

• Improve soil quality
• Increase nutrient availability
• Provide shelter and resources for other organisms

This ongoing interaction between organisms and their environment drives the ecosystem toward greater complexity and stability.

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Key Takeaways

• Ecological succession explains how ecosystems develop and change over time.
• Early scientists like Cowles and Clements played a major role in shaping this concept.
• Primary succession begins in lifeless areas, while secondary succession occurs after disturbances.
• Pioneer species are essential for starting ecosystem development.
• Each stage of succession modifies the environment, making it suitable for future species.
• Secondary succession is faster because soil and nutrients are already available.
• The climax community represents a stable and mature ecosystem.