Both hydrarch and xerarch successions lead to medium water conditions (mesic): neither too dry (xeric) nor too wet (hydric).
In primary succession in water, the pioneers are the small phytoplanktons, they are replaced with time by rooted-submerged plants, rooted-floating angiosperms followed by free-floating plants, then reed swamp, marsh-meadow, scrub and finally the trees. The climax again would be a forest. With time the water body is converted into land.