Structure of Two Communities Dominated by Copernicia Alba and Associations With Soil and Inundation in Pantanal Wetland, Brazil

Abstract

Known for its high degree of biodiversity, the tropics have a number of sites in which one or few species dominate large areas, as occurs in the Pantanal wetland, Brazil, with the 'carandá' palm, Copernicia alba, in monodominant formations known regionally as 'carandazal'. The aim of the present study was to analyze variations in species richness and diversity of herbs, shrubs and trees in two communities dominated by Copernicia alba with different flood patterns and determine whether soil fertility and time of inundation are associated with tree/shrub species composition and abundance. Vegetation was analyzed in 50 plots measuring 100m 2 in each area, with the determination of the tree/shrub component (CBH ≥ 5cm). Three subplots measuring 1m 2 were demarcated within each plot for the sampling of herbs, sub-shrubs, shrubs (CBH < 5cm) and juvenile arboreal species. Soil samples were taken from three depths in each 100m 2 plot. Associations between soil data, time of inundation and absolute density of tree/shrub vegetation were tested using canonical correspondence analysis (CCA). For the tree/shrub component, a total of 22 species belonging to 12 families were sampled in the two communities. Richness was greater in the area submitted to a lesser time of inundation. Copernicia alba had the greatest importance values in both study areas, followed by Tabebuia aurea in one community and Mimosa glutinosa in the other. In the subplots, 178 species belonging to 39 families were sampled, for which Fabaceae, Poaceae, Asteraceae and Cyperaceae figured prominently. The herbaceous component predominated over the others in species richness in both areas, but similarity was low. CCA detected associations between soil fertility, time of inundation and composition of tree/shrub species. The richness of the tree/shrub component was greater in the area with a shorter inundation time, which makes this event an important factor in the determination of C. alba monodominance in the Pantanal wetland. The herbaceous component demonstrated a high degree of richness and diversity in both communities, although there are differences in the inundation pattern between the two areas. RESUMOESTRUTURA DE DUAS COMUNIDADES DOMINADAS POR COPERCIA ALBA E ASSOCIAÇÕES COM SOLO E INUNDAÇÃO NO PANTANAL, BRASIL. A região tropical conhecida por elevada diversidade detém, em alguns locais, uma ou poucas espécies dominantes em extensas áreas, como ocorre no Pantanal com a palmeira 'carandá' Copernicia alba que constitui formações monodominantes denominadas regionalmente como 'carandazal'. O Objetivo do presente estudo foi analisar a variação na riqueza e diversidade de espécies herbáceas, arbustivas e arbóreas em duas comunidades dominadas por

Structure of arboreal and herbaceous strata in a neotropical seasonally flooded monodominant savanna of Tabebuia aurea

“…Such low diversity of woody species is reported for other monodominant formations (Nascimento and Cunha 1989;Arieira and Cunha 2006;Amador et al, 2012), demonstrating that the higher perennials appear such as Echinodorus grandiflorus, E. paniculatus, E. teretoscapus, Ludwigia lagunae, L. octovalvis, L. tomentosa, Pontederia cordata, P. subovata (Pott and Pott, 2000). Whereas Axonopus leptostachyus, Paspalum laxum, Reimarochloa acuta, Setaria parvilfora are indicators of dry periods (Pott and Pott, 1994;Schessl, 1999).…”

“…And there was also a lower value from Carandazal of the sub-region of Miranda (1.15) and a higher one for Carandazal of the sub-region of Nabileque (0.33) (Amador et al, 2012). These differences in the compared diversity values, are associated to environmental conditions, such as the lower value recorded for Carandazal from Nabileque.…”

“…These differences in the compared diversity values, are associated to environmental conditions, such as the lower value recorded for Carandazal from Nabileque. The reason is that areas under inundation of the Paraguay River are subject to more strict conditions (Amador et al, 2012). Schessl (1999) observed that in the more flooded Pantanal environment of Poconé, there is a strong variation in the coverage and composition of species promoted by hydric seasonality.…”

“…Most of these formations are seasonally flooded savannas. The main studies of monodominant formations in the Pantanal are (i) of V. divergens forest in the sub-region of Poconé (Nascimento and Cunha, 1989;Arieira and Cunha, 2006); (ii) of C. alba palm savanna in the sub-regions of Miranda and Nabileque, Mato Grosso do Sul (Amador et al, 2012); and (iii) of the arboreal stratum of T. aurea in the sub-region of Miranda (Ribeiro and Brown, 2002;Soares and Oliveira, 2009).…”

“…As a consequence, the species richness found is usually very low. However, in a study on C. alba savanna Amador et al (2012) demonstrated that it is species-rich when the herbaceous stratum is included. As herbs constitute the major part of the floristic diversity of the Pantanal (Pott and Pott, 1999;Schessl, 1999), it is possible that all the monodominant formations of the Pantanal are in fact species-rich.…”