First Organisms to Appear During Primary Succession

Definition

• Lichens are small creatures that are composites of algae and fungi. They use photosynthesis to create food and grow, but are not to be confused with plants. Lichens take many forms, and can appear leafy, small and crusty or shrub-like. These tiny organisms are able to survive in the most inhospitable places with extremely cold temperatures or extremely hot ones, but can thrive in more temperate climates as well.

Purpose

• The purpose of lichen is essentially to prepare an area for future growth. Lichens do this by slowly building soil over bare rock surface, which is created by the lichens producing acids that enable them to take nutrients from their surroundings. These lichen-created acids gradually break down a rock surface and, collecting this along with debris carried from wind and erosion around them, create soil. After there is enough soil, plants take root and begin to grow.

Lifespan

• Lichens first begin to colonize a bare area within a year of the natural event that created that barren state. Depending on outside factors such as erosion and weather events, it can take longer. Lichens grow very slowly, and have no set life limit. There are some lichen colonies with estimated ages of 9000 years old. The death of lichen nevertheless aids in soil development.

Next Stages

• After lichens comes grass, about two to four years after lichen growth. Between five and 20 years after that, shrubs can grow in the area. Twenty-five to over a hundred years later, a forest can develop along with animals. As ecological succession progresses, nature communities become more complex and developed. This whole process can take hundreds of years.