Question

Explain the differences and similarities between hydrarch and xerarch succession of plants.

Answer 1

The succession of the plants is called the succession of hydrach or xerarch, depending on the nature of the environment, whether it is water (or very wet areas) or very dry areas.

Complete answer:

Hydrarch	Xerarch
This succession takes place in wet areas	This succession takes place in dry areas
This takes place from hydric to mesic condition	This takes place from xeric to mesic condition
This starts from phytoplankton stage	This starts from bare rocks

Both the hydrarch and xerarch successions, neither too dry (xeric) nor too wet (hydric), lead to medium water conditions (mesic).

Succession to Xerarch
Pioneer species are named the species that invade a bare field. In primary rock succession, lichens are the pioneer species that can secrete acids to dissolve rock, assist in weathering and soil formation, and the small soil leads to bryophyte growth.

Over time, larger plants succeed the bryophytes, and finally a stable climax forest population is established after many more phases, and eventually the xerophytic habitat is transformed into a mesophotic.

Hydrarch succession
The pioneers are the tiny phytoplankton substituted by free-floating angiosperms with time,
Rooted hydrophytes, sedges, grasses and eventually the trees are replaced by free-floating angiosperms.
Again the climax will be a forest, and the water body is turned into land over time.

Similarities:
i) Both successions of hydrarch and xerarch contribute to conditions of medium water and wet conditions.
ii) Both end in the forest and both contribute to mesic conditions.

Note: Four stages of the succession of hydrarch:
1. Submerged in shallow water by aquatic plants.
2. Emergent cattails and bulrushes have their origins in shallow water mud.
3. Thickets of willow along the shores of a distant shoreline.
4. Conifer forest over willow thickets in drier, well-drained soil.