Secondary succession is one of the two types of ecological succession

Ecological succession

Ecological succession, is the phenomenon or process by which a community progressively transforms itself until a stable community is formed. It is a fundamental concept in ecology, and refers to more or less predictable and orderly changes in the composition or structure of an ecological community...

 of plant life. As opposed to the first, primary succession

Primary succession

Primary succession is one of two types of biological and ecological succession of plant life, occurring in an environment in which new substrate devoid of vegetation and usually lacking soil, such as a lava flow or area left from retreated glacier, is deposited...

, secondary succession is a process started by an event (e.g. forest fire, harvest

Harvest

Harvest is the process of gathering mature crops from the fields. Reaping is the cutting of grain or pulse for harvest, typically using a scythe, sickle, or reaper...

ing, hurricane) that reduces an already established ecosystem

Ecosystem

An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

 (e.g. a forest or a wheat field) to a smaller population of species, and as such secondary succession occurs on preexisting soil

Soil

Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 whereas primary succession

Primary succession

Primary succession is one of two types of biological and ecological succession of plant life, occurring in an environment in which new substrate devoid of vegetation and usually lacking soil, such as a lava flow or area left from retreated glacier, is deposited...

 usually occurs in a place lacking soil.

Simply put, secondary succession is the succession that occurs after the initial succession has been disrupted and some plants and animals still exist. It is usually faster than primary succession as:

1. Soil
   Soil
   Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
   
    is already present, so there is no need for pioneer species
   Pioneer species
   Pioneer species are species which colonize previously uncolonized land, usually leading to ecological succession. They are the first organisms to start the chain of events leading to a livable biosphere or ecosystem...
   
   ;
2. Seeds
   SEEDS
   SEEDS is a voluntary organisation registered under the Societies Act of India....
   
   , root
   Root
   In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
   
   s and underground vegetative organs of plants may still survive in the soil.

The mechanism of secondary succession in Imperata grassland

Many mechanisms can trigger secondary succession including facilitation, inhibition, trophic interaction, initial composition, and competition-colonization trade-offs. The factors that control the increase in abundance of a species during succession may be determined mainly by seed production and dispersal, micro climate; landscape structure (habitat patch size and distance to outside seed sources);Bulk density, pH, soil texture (sand and clay).

The effect of secondary succession on vegetation

Imperata grasslands are caused by human activities such as logging, forest clearing for shifting cultivation, agriculture and grazing, and also by frequent fires. The latter is a frequent result of human interference. However, when not maintained by frequent fires and human disturbances, they regenerate naturally and speedily to secondary young forest. The time of succession in Imperata grassland (for example in Samboja Lestari area), Imperata cylindrica has the highest coverage but it becomes less dominant from the fourth year onwards. While Imperata decreases, the percentage of shrubs and young trees clearly increases with time. In the burned plots, Melastoma malabathricum, Eupatorium inulaefolium, Ficus sp., and Vitex pinnata. strongly increase with the age of regeneration, but these species are commonly found in the secondary forest.

The effect of secondary succession on soil parameters

Soil properties change during secondary succession in Imperata grassland area. The effects of secondary succession on soil are strongest in the A-horizon (0-10 cm), where an increase in carbon stock, N, and C/N ratio, and a decrease in bulk density and pH are observed. Soil carbon stocks also increase upon secondary succession from Imperata grassland to secondary forest.

Challenges to restore Imperata grassland

Imperata grassland is a commonly found vegetation type in Kalimantan, Indonesia, and other parts of South-East Asia. It indicates a high degree of degradation of the vegetation, and mostly occurs after slashing and burning of primary forests. Imperata grasslands are not a final and stable stage of land degradation, but, when not maintained by frequent fires and human disturbances, regenerate spontaneously and swiftly to secondary young forest. The introduction of native shrubs and trees will speed up this process. Therefore, the assumption is not correct that Imperata grasslands are a final stage of land degradation and are very difficult to recover for more valuable land uses.