Abiotic control of the vegetation in Peruvian Amazon floodplains : environment change and pioneer species / Risto Kalliola.

Tese (doutor) - University of Turku, 1992

Floodplain vegetation is studied using a combination of satellite remote sensing and field surveys. It is shown that the floodplain environments of the lowland Peruvian Amazon are highly instable and heterogeneous due fluvial processes of flooding, sedimentation and channel migration. Because most of the soils occupied by rain forest are of fluvial sediment origin, the soils on unflooded terra firme are also likely to exhibit heterogeneity that corresponds to characteristics typical of fluvial depositional environments. Botanical surveys of colonizing vegetation on new sites formed by active fluvial dynamics indicate that, in spite of the large species pool of the Amazon, only a few plant species are present. One of these is the giant red-grass Gynerium sagittatum, which has two or three sympatric variants, differing in their morphology, life-history characters and ecology. In order to determine whether the variants could be considered separate taxa, a taxonomical treatment was carried out, resulting in description of two new varieties. In the Introduction, selected ecological and phytogeographical aspects of vegetation in the lowland Peruvian Amazon are brought together and discussed in the light of the articles included.