Table of Contents
Primary Succession Definition
Ecological succession refers to the gradual evolution of a group of species or a community through time, such as decades or millions of years. Typically, one dominating group of living forms has succeeded in establishing a stable climax community across a certain region.
What is Primary Succession?
A Primary succession is an ecological succession in which a group of species or a community colonises a freshly created region for the first time. Topsoil and organic materials are generally sparse in this formerly deserted, desolate region.
The pioneer species is the species that colonises an unoccupied region for the first time, and the pioneer community is the dominant community. Soon, a broader diversity of plants and animals will populate the region, leading to the formation of a climax community.
The species occupying the region might be replaced by a new ecological succession, called secondary succession, if disturbed or interfered with by a disruptive external or internal cause.
Because the region had previously been occupied during the first succession, the second succession might happen much faster, in decades or even hundreds of years, as opposed to thousands or even millions of years during the initial succession.
Primary Succession Etymology
Adolphe Dureau de la Malle, a French scientist, was the first to use the term succession in an ecological context. The term refers to the growth of plants following forest clear-felling.
Type of Primary Succession
The process starts with a bare rock produced by volcanic eruptions or receding glaciers in this figure. The pioneer species (lichens and moss) that grow on the rock are the next stage. These species’ death and subsequent decomposition contribute to the creation of soil.
Grass and herbaceous plants are the next category of plant invaders. After that, shrubs and bushes take their place, followed by trees. Animals inhabiting the region are growing more varied as the diversity of plant species improves.
However, when competition for sunshine, space, and nutrients increases, those that are better suited and more tolerant, such as “shade-tolerant trees,” survive and grow.
i. Primary Succession
A succession of prevailing species communities in a certain environment characterises both kinds. They differ in terms of the habitat’s ecological history and genesis.
When a group of species or a community colonises a barren, freshly created environment, for example, this is known as primary succession.
The formation of plant or animal communities in a location where there is no soil at first, such as bare rocks created by a lava flow, is an example of primary succession. The colonization of a barren region following a catastrophic landslide or newly exposed land from retreating glaciers are two more instances.
Another is the colonisation of difficult environments like sand dunes. Sand dunes are only habitable by a few highly specialised flora and animals due to their extraordinarily scorching temperatures.
ii Secondary Succession
When a previously inhabited region is colonised by a new dominant group of species or communities, this is known as secondary succession.
In secondary succession, new occupants take the place of earlier groups in a habitat that has been affected by an ecological disturbance. The source of the disruption might be external or internal. The recolonization of a burned-out region is an example of secondary succession.
The habitat type is another distinction between main and secondary successions. Living creatures colonise a barren terrain, which implies it lacks topsoil, in primary succession.
In secondary succession, on the other hand, living creatures will re-colonize a previously occupied region, resulting in topsoil containing organic materials from the previous occupants.
Primary Succession Process
Primary succession takes a long time to develop and complete, perhaps a thousand years or more. On the other hand, secondary succession frequently happens more quickly, taking just a decade or a hundred years. This is due to the fact that most living forms would find a freshly created region undesirable at first.
The newly created area, for example, would be devoid of soil and made up entirely of bare rocks. Primary succession begins at this stage. A sequence of physicochemical modifications must take place till they become more hospitable to life.
Pioneer species are species that may effectively establish and control a newly created or previously unoccupied territory. Pioneer communities are communities that have successfully developed and dominated newly formed or previously uninhabited land.
A community is an ecological unit made up of a collection of organisms or a population of several species that live in a certain region. A community can be a tiny population living in a small area (such as a pond) or a huge geographical region that defines a biome.
The colonisation phase of primary succession begins with the establishment of a pioneer village. Lichens, algae, and fungus are examples of pioneer species.
These species are more tolerant, and by breaking down rocks into tiny pieces, they eventually contribute to the creation of soil. They also provide organic materials for the environment. The region eventually became loaded with thin soil, making it suitable for the establishment of higher kinds of species.
Intermediate species are the following species that invade and dominate the region. Grasses and shrubs that flourish on thin soils are examples. A greater diversity of plants and tiny animals can occupy the region as the environment improves.
The formation of a climax community, or a community made up of even higher forms of life, such as shade-tolerant plants and taller trees that attract larger and higher types of animals, is the last step.
Secondary Succession Process
The second succession happens when the habitat is subjected to a disturbance that threatens the habitat’s occupants. Because the region is already populated by plants and animals, it will likely stay livable after the disruption, making re-colonization quicker and more accessible.
In secondary succession, top soil is found whereas is absent in primary succession. Shorter period is seen in secondary succession and longer duration in primary succession.
Example are retreated glaciers for primary succession and tornado’s, flood, fire are secondary succession. A third kind, known as cyclic succession, occurs when a group of species gradually replaces a previously dominating species over time without causing large-scale disruption.
Importance of Primary Succession
The main succession is critical for pioneering the region and creating suitable conditions for the establishment of additional plants and animals. It prepares the stage for future successions, since formerly flourishing organisms may become an important part of the soil.
Because pioneer species are more tolerant of adverse environments, they might take the available nutrients and transform them into a form that other life forms could utilise.
Primary Succession Citations
- How lichens impact on terrestrial community and ecosystem properties. Biol Rev Camb Philos Soc . 2017 Aug;92(3):1720-1738.
- Changes through time: integrating microorganisms into the study of succession. Res Microbiol . 2010 Oct;161(8):635-42.
- Gopher mounds decrease nutrient cycling rates and increase adjacent vegetation in volcanic primary succession. Oecologia . 2014a Dec;176(4):1135-50.