Freshwater sponges as indicators of floodplain lake environments and of river rocky bottoms in Central Amazonia

Abstract

Two complementary surveys were carried out in the same area of the Araguaia River Basin, Central Amazonia, Brazil: one of sponges in the low water, the other of the water quality in the dry and the high water. Two environments were selected for the sponge survey: an exposed rocky bottom stretch of the river and several nearby várzea lakes. This revealed seasonal sponge assemblages characteristic of each of the two habitats. The high water parameters detected in the river and várzea lakes come out now as the ones which set the first ecological frame for this seasonal fauna and are required for gemular eclosion and growth.