Question: 100: The pioneer species in a hydrarch succession are:
(1) Free-floating angiosperms
(2) Submerged rooted plants
(3) Phytoplanktons
(4) Filamentous algae
Answer: Option (3)
Explanation:
Hydrarch succession, also known as hydrosere, begins in aquatic habitats such as ponds or lakes.
The first organisms to colonise such bare aquatic environments are microscopic, simple,
and capable of surviving in water with minimal nutrients.
Phytoplanktons are microscopic photosynthetic organisms that float freely in water and act as primary producers.
They initiate succession by synthesising organic matter and gradually increasing the nutrient content of the water body.
Their death and decomposition contribute organic matter to the bottom, making the environment suitable for higher plant forms.
Thus, phytoplanktons act as the pioneer species in hydrarch succession.