Josseline Zuniga
LaPrad
Honors Bio, 6
May 21 2013
Ecological Succession Ecological succession is a naturally occurring phenomenon where life appears in either previously uninhabited areas of returns to a previously inhabited area destroyed by what is known as a disturbance. This can include such things as a forest fire, lava flow, a lake evaporating, and/or even newly exposed rocks. Primary succession is when vegetation appears in an area where there were no previous communities. It usually occurs when pioneer species and water begin to normalize a previously uninhabited area. For example, after a volcanic eruption and subsequent lava flow, the area scorched by the lava becomes rich in minerals and small organisms begin to populate. Another example is a glacier retreating and exposing new soil. Small vegetation and fungi begin to cultivate the soil enabling larger species to move in and populate the area. Primary succession is commonly natural and not usually forced by humans.
Succession occurring from an area that previously held a community and was subjected to a disturbance is called secondary succession. Examples of this are vegetation returning to a forest fire site or a dried lake bed. Secondary succession is also commonly related to human interactions with the environment. When a city is built tress around the city must be downed and the land leveled. When small plants begin to grow in between cracks in the concrete, secondary succession has occurred.
The third type of succession, also the most common, is called seasonal succession. However this type of succession is often disputed to be one. Some scientists claim that there is no real disturbance. In this type of succession, species die out during a certain season and return when conditions are suitable for them once again. Because the disturbance occurs routinely, it is usually rejected as one of the successions.
The final stage, or the return to normality, of succession is called the climax. For a community to reach its climax it must be able to withstand the environment around it, have a diverse array of species, have multiple food chains and reach equilibrium between all species. There are also different types of climaxes. The first is climactic climax, which is when all the species reach normality again and reform or establish a community at, or near, the same time. Edaphic climax is when more than one community establishes and reaches normality in the same area at the same time. Catastrophic climax is when a community reaches equilibrium and then is again hit by a disturbance and cannot recover. There are other types of climaxes that are each subcategories of the previous three. These are dependant of geographical location and length of time needed to reach climax.
The area that is attempting to reach a climax is called a sere. A community growing toward climax in a fresh body of water is called a hydrosere, on a rock or barren land a lithosere, in a dry area xerosere, in a salt water body a halosere, and on sand a psammosere. Seres are not the land after the disturbance they are the area once a community begins to return.
Frederic Clements was born in Lincoln, Nebraska on September 16, 1874, Clements was one of the leading plant ecologists of the century. As a young child Clements enjoyed sitting outside and collecting plants. Clements studied botany at the University of Nebraska at the age of 16 and stayed on to receive his masters in botany in 1896 and is PhD in 1898. He married his wife Edith a year after achieving his PhD in 1899. His wife got her PhD in 1904. He was professor for 13 years before founding a research lab and began to work there. Clements died on July 16, 1945.
Clements research on succession led him to conclude that there are six phases or stages in succession.
Nudation-E.S. begins with a disturbance of a barren site.
Migration- New species begin to move in and cultivate soils. Ex. Fungi and bacteria.
Ecesis-