Inundation forests in Central Amazonia and their adjacent shores are covered by several meters of flood water for 5-7 months each year, due to the monomodal periodic flood pulse of rivers. Terrestrial invertebrates have adapted to this ecosystem by evolving several survival strategies. The fauna comprises both, terricolous and arboricolous animals. Both groups include non-migrants and migrants. Migratory reaction of terricolous animals is horizontal (following the high-water line), vertical (temporal ascent to trunk or canopy of trees) or includes a temporal flight to upland forests. Non-migrants have active or dormant stages under water. The latter pass inundation in naturally available retreats, in self-made retreats or as eggs. Non-migrant arboricolous animals reproduce and live exclusively in the trunk and canopy region, whereas migrants include life stages that live on the ground as well. Characteristics and examples of species are given for each of these categories. The flood pulse is regarded as the original determinant of migration. However, most invertebrates have become sensitive to secondary, mainly abiotic factors. Only in a few species is migration still directly related to the cycle of flooding.
flood pulse; inundation forests; migration; terrestrial invertebrates; survival strategies; Amazon