The dynamics, distribution and classification of swamp vegetation in Peruvian Amazonia

Abstract

Swamp vegetation was surveyed in the western Amazon lowlands (<500 m above sea level) using Landsat MSS and TM imagery, radar maps and ground truth surveys. Four categories of swamp vegetation were recog nized on the basis of the physiognomy: (I) herbaceous swamp, (II) shrub swamp, (HI) palm swamp and (IV) forest swamp. The total coverage of the swamp vegetation recognized was 24 900 km2 or 3.4% of the study area. Of these swamps, 19% are situated in flood basin areas, 8% in blocked valleys, and 73% belong to the Maranon wetland complex, where no detailed swamp classification was carried out The largest swamp areas are located in the central parts of the intra-foreland basins Pastaza-Mara non and Ucayali, which are characterized by widespread inundations and aggradation. Mobile river channels cause alterations in inundation con ditions, which lead to local forest destruction and succession. The insta bility of the swamp site physiography makes swamp vegetation classi fication difficult. The suggestion is made that future studies on swamp vegetation should also contain descriptions of the swamp site geo morphology, the type of flood water received (rivers, rain) and the hydrology (flood regime).