Ecological Succession

Out With the Old… Major disturbances, either natural or anthropogenic, greatly alter the plant community in some areas. Once bountiful areas of plant growth can become desolate and very inhospitable. Pioneer species of plants can move into these high light or low nutrient environments and establish a plant presence. As these pioneer species grow, they change the biotic and abiotic factors in the ecosystem for the better. Once the soil of the ecosystem has been “reclaimed” by the pioneer species, other plants may move in, out-compete and replace the pioneers in a process called ecological succession.

Primary Succession Primary succession occurs when a community of life arises in an areas that there was lifeless. (e.g. Volcanic Islands) Microorganisms are usually the first to arrive followed quickly by lichens and moss. Nutrient-bearing soil forms from the remains of these early colonizers. Seeds of grasses and other smaller plants arrive via animals and/or wind and begin to succeed the pioneers.

Secondary Succession Secondary succession occurs when a disturbance occurs within a community that damages the existing community but leaves the soil in tact. (Soil quality is lost in primary succession.) A field may be ravaged by fire – this kills the plants but leaves soil in tact. Fast-growing, annual species can grab a foothold and grow in the field and act as the primary species. These will then be succeeded by other species over time.

Climax Communities A climax community is a stable, self- perpetuating community that existed in equilibrium with the area’s biotic and abiotic factors. Many factors, not just climate, will determine which community will be stable in a particular region. Precipitation and temperature are still very important but factors such as topography, soil quality, bacterial presence and animal species also play an important role.

Succession & Biodiversity As the plant community changes, so do the animals that rely on the differing species of plants in the area. As the plant life changes, there can be changes in the soil quality and ground temperature which impacts animal life present in the ecosystem. A large biome with roughly the same climate will be composed of many smaller “patches” with various degrees of animal and plant life.

That’s All I Got… No Peter Griffin this time…let’s just enjoy the sunset…