Mangrove vegetation changes on Holocene terraces of the Doce River, southeastern Brazil

Abstract

High-resolution sedimentological, geochemical and pollen analysis on sediment core from the coastal plain of the Doce River, southeastern Brazil, revealed changes in the depositional system and vegetation caused by combined action of oscillations in relative sea-level (RSL) and sedimentary supply during the Holocene. Two main phases were discerned using sedimentary features, δ 13 C, δ 15 N, total organic carbon (TOC), total nitrogen (N), C/N and cluster analysis of pollen data, temporally synchronized with radiocarbon age dating. The data indicates the presence of a lagoon system surrounded by a tidal plain colonized by mangroves and its sedimentary organic matter sourced from C 4 plants between ~ 8050 and ~ 7115 cal yr BP. However, during the mid- and late-Holocene the mangroves shrank and freshwater vegetation expanded (C 3 plants), probably, due to a marine regression. During this phase, the development of a lacustrine environment was followed by the colonization of herbs, trees and shrubs. The continuous sediment infilling into the lake allowed the expansion of a herbaceous plain as seen today. This geomorphologic and vegetation evolution is in agreement with the mid-Holocene RSL maximum above present RSL and subsequent fall to the present time. • We analyze pollen, sediment and geochemical data of a core from a coastal plain in Brazil. • Changes in the depositional system and vegetation were caused by relative sea-level changes. • During the early Holocene occurred a lagoon system surrounded by mangroves. • In the middle and late Holocene the mangroves shrank and freshwater vegetation expanded.