Ecological succession

Ecological succession is the gradual, fairly predictable change in the species that make up a community over time. Primary succession begins where there is no soil at all, such as bare rock left by a retreating glacier or new land formed from cooled lava. Pioneer species like lichens and mosses are the first to grow; they help break down rock and, as they die and decay, start to build a thin layer of soil. In many places, grasses and small plants follow, then shrubs, and eventually trees, with the animal community changing along with the plants; in dry, cold, or often-disturbed areas, a community may stay as grassland or shrubland instead. Secondary succession happens where a disturbance, such as a wildfire, a flood, or an abandoned farm field, removes much of a community but leaves the soil in place. Because soil, and often seeds and roots, remain, secondary succession is usually much faster than primary succession. Over time a community may reach a relatively stable stage, sometimes called a climax community, though ecologists now recognize that disturbances happen often enough that many communities keep changing. The 1980 eruption of Mount St. Helens gave scientists a rare chance to watch life return to a devastated landscape.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report