|Class 12 Biology Ecosystem||Succession of Plants|
Succession of Plants
Based on the nature of the habitat, whether it is water (or very wet areas) or it is on very dry areas – succession of plants is called hydrach or xerarch succession respectively.
Succession takes place in wetter areas and the successional series progress from hydric to the mesic conditions is called hydrach succession.
Succession takes place in dry areas and the series progress from xeric to mesic conditions is called xerarch succession.
Both hydrarch and xerach successions lead to medium water conditions (mesic) – neither too dry (xeric) nor too wet (hydric).
The species that invade a bare area are called pioneer species.
In primary succession on rocks, thepioner species is lichens are able to secrete acids to dissolve rock, helping in weathering and soil formation and the little soil leads to the growth of bryophytes.
With time, the bryophytes are succeeded by bigger plants, and after several more stages, ultimately a stable climax forest community is formed and ultimately the xerophytic habitat gets converted into a mesophytic one.
The pioneers are the small phytoplanktons which are replaced with time by free-floating angiosperms,
The free-floating angiosperms are replaced by rooted hydrophytes, sedges, grasses and finally the trees.
The climax again would be a forest and with time the water body is converted into land.
All succession whether taking place in water or on land, proceeds to mesic community.
Fig. diagrammatic representation of hydrach succession