Structure and phytogeographic relationships of swamp forests of Southeast Brazil

Bruno Coutinho Kurtz,Fabio Rubio Scarano,Jorge Caruzo Gomes

doi:10.1590/s0102-33062013000400002

Abstract

Swamp forests are associated with soils that are saturated or inundated because of a high water table. In Brazil, little is known about the plant ecology of such forests. In this paper, we aimed to describe the phytosociological structure of the tree layer of swamp forests in Restinga de Jurubatiba National Park, in the northern part of the state of Rio de Janeiro, and to evaluate the floristic similarities between these forests and some other possibly related types of vegetation formations in Brazil. The sampling included 84 species, within 62 genera and 34 families. The Shannon diversity index was 3.42, and the Shannon evenness index was 0.77. The forests studied showed an oligarchic structure; Tapirira guianensis, Calophyllum brasiliense and Protium icicariba were the most important species. Oligarchy, or monodominance, and relatively low species richness are the norm in the swamp forests of southeastern Brazil and result from the strong selective character of the saturated/inundated soils. In comparison with local areas of restinga (coastal woodland), Atlantic Forest sensu stricto, other swamp forests and flooded riparian forests, the similarity was low (Jaccard similarity coefficient < 0.25). In addition to the similar ecological conditions, geographic proximity was a key factor determining the patterns of similarity found. Our results indicate that the swamp forests of southeastern Brazil do not represent a distinguishable floristic unit, due to sources of local variation, notably migration and the establishment of adaptive species from neighboring vegetation formations (some 70% of the species surveyed).

Highlights

Swamp forests comprise vegetation that develops on soils saturated or inundated by the water table (WCMC 1992; Scarano 2006)
The objective of this study was to describe the phytosociological structure of the tree layer of the swamp forests in southeastern Brazil, as well as to determine the extent to which they are floristically similar to local areas of open restinga, Atlantic Forest sensu stricto, other swamp forests, and flooded riparian forests
Our study area was within Restinga de Jurubatiba National Park (22°08’-22°19’S; 41°17’-41°43’W), which is located on the northern coast of the state of Rio de Janeiro, in southeastern Brazil (Fig. 1)

Summary

Introduction

Swamp forests comprise vegetation that develops on soils saturated or inundated by the water table (WCMC 1992; Scarano 2006). In Brazil, such forests are known by a variety of local names (Dorneles & Waechter 2004) These forests are naturally fragmented and are associated with hydromorphic soils, occurring near springs, on the banks of rivers or lakes and within natural topographic depressions (Ivanauskas et al 1997; Toniato et al 1998; Jacomine 2004). They are widely distributed throughout the neotropics and present interfaces with various types of vegetation formations, including different types of forests and grasslands (Teixeira & Assis 2011). The authors of such studies have focused their analyses on swamp forests located on the Brazilian Highlands, evaluating only two areas of swamp forest in the coastal plains, where a number of local surveys have already been conducted (Tab. 1)

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