Practice question

A pond progressing toward marsh, meadow, shrubland, and eventually forest under a suitable climate is the classic hydrosere or hydrarch succession. Aquatic plants and phytoplankton add organic matter, while incoming mineral sediment is trapped by vegetation. Decomposition is incomplete in waterlogged conditions, so the basin gradually fills and becomes shallower. Submerged plants give way to floating and emergent vegetation, then sedges, grasses, shrubs, and terrestrial trees as soil aeration improves. Primary succession describes establishment where a prior soil community is absent and can include a hydrosere, but it does not specify the water-to-land direction. Secondary succession starts after disturbance where soil remains. Xerarch succession begins in dry conditions, often on bare rock or sand, and follows the opposite moisture context. Pond infilling is not inevitable: floods, dredging, water-level changes, or stable basin morphology can maintain open water. Nevertheless, the defining mechanism is terrestrialization driven by sediment and organic accumulation, which makes “hydrarch succession” the specific name for this sequence.