Comparações florísticas e estruturais entre duas comunidades lenhosas de cerrado típico e cerrado rupestre, Mato Grosso, Brasil

Abstract

Comparações fl orísticas e estruturais entre duas comunidades lenhosas de cerrado típico e cerrado rupestre, Mato Grosso, Brasil RESUMO (Comparações fl orísticas e estruturais entre duas comunidades lenhosas de cerrado típico e cerrado rupestre, Mato Grosso, Brasil). Comparou-se a riqueza, a composição fl orística e a estrutura da vegetação lenhosa entre um hectare de cerrado rupestre (CR) e um de cerrado típico (CT) no leste Mato-grossense. A riqueza registrada (CT = 79 e CR = 71) e estimada pelo método de bootstrap (CT = 86,7 ± 2,3 e CR = 75,8 ± 1,8) foi maior no CT, mas o índice de diversidade foi igual entre as duas fi sionomias (3,58 no CT e 3,56 no CR; teste t de Hutcheson = t 2;0,05 = 0,43, p > 0,05). Apesar da elevada similaridade fl orística (Sørensen = 0,75 e Morisita = 0,73), a análise de ordenação (DCA) separou as parcelas do CT e do CR, indicando a seleção de espécies nas duas fi sionomias. Foram registradas altas porcentagens de indivíduos mortos no CT (28,1%) e no CR (17,3%), devido à ocorrência de uma queimada quatro meses antes da amostragem da vegetação. A área basal por parcela foi maior no CR, enquanto as densidades por parcela, as alturas e os diâmetros medianos dos indivíduos, não diferiram entre as duas fi sionomias, sugerindo que o solo raso e o afl oramento rochoso no CR não limitaram o estabelecimento e o desenvolvimento da fl ora lenhosa.Palavras-chave: diversidade, fogo, savana, substrato rochoso Letícia Gomes 1,2 , Eddie Lenza 1 , Leandro Maracahipes 1 , Beatriz Schwantes Marimon 1 e Edmar Almeida de Oliveira 1 ABSTRACT (Floristic and structural comparisons of two woody communities of typical and rocky cerrado in the state of Mato Grosso, Brazil). In this work, the vegetation richness, fl oristic composition and the structure of woody plants of 1 hectare of rocky cerrado ("cerrado rupestre") (CR) and 1 hectare of typical cerrado (CT), in eastern Mato Grosso, were compared. Th e observed (CT = 79 and CR = 71) and the estimated richness (CT = 86.7 ± 2.3 and CR = 75.8 ± 1.8), using bootstrap analysis, were higher in the CT, but the diversity index was the same for both physiognomies (3.58 in CT and 3.56 in CR; Hutcheson t test = t 2;0.05 = 0.43, p > 0.05). Despite high fl oristic similarity (Sørensen = 0.75 and Morisita = 0.73), the ordination analysis (DCA) separated the CT and CR plots, which indicated species selection in both physiognomies. A percentage of dead individuals in CT (28.1%) and CR (17.3%), due to fi res four months before sampling took place, was also found. Th e CR basal area per plot was higher, and densities per plot, heights and mean diameters of individuals did not diff er between both physiognomies, which suggests that the shallow soil and rocky outcrop of CR have not limited the establishment and development of the woody fl ora.

Influence of edaphic variables on the floristic composition and structure of the tree-shrub vegetation in typical and rocky outcrop cerrado areas in Serra Negra, Goiás State, Brazil

“…The species on the left side of axis 1 of the CCA were exclusive to or most abundant in TC, such as Byrsonima pachyphylla, Roupala montana, and Davilla elliptica, and were associated with greater values of clay, silt, base saturations, Ca, and Mg. Tree-shrub cerrado savanna formations growing on rocky substrates might be expected to have reduced plant densities (Ribeiro & Walter 2008) -which could limit species richness. However, both the recorded and estimated (Bootstrap) species richnesses of RC were greater than those of TC in the present study, and similar studies undertaken in rocky outcrop cerrado areas in central Brazil corroborate this similarity in species richness between the two formations (Pinto et al 2009, Moura et al 2010, Gomes et al 2011. Hypothesis 1, that RC areas should be more restrictive to the establishment of plant species because of their rock outcrops and shallow soils, was not corroborated in the present study or by other studies undertaken in the Cerrado biome (Pinto et al 2009, Gomes et al 2011).…”

“…However, both the recorded and estimated (Bootstrap) species richnesses of RC were greater than those of TC in the present study, and similar studies undertaken in rocky outcrop cerrado areas in central Brazil corroborate this similarity in species richness between the two formations (Pinto et al 2009, Moura et al 2010, Gomes et al 2011. Hypothesis 1, that RC areas should be more restrictive to the establishment of plant species because of their rock outcrops and shallow soils, was not corroborated in the present study or by other studies undertaken in the Cerrado biome (Pinto et al 2009, Gomes et al 2011). As such, it can be concluded that the shallow substrate and uneven topography of rocky outcrop cerrado sites are not determinate factors of local richness or alpha-diversity , Moura et al 2010.…”

Dynamics of the woody vegetation of two areas of Cerrado sensu stricto located on different substrates

“…In addition, these small changes were due to species that occur at low densities, where the death or recruitment of a small number of individuals may easily provoke a decrease or increase in species richness. While the CT and CR were similar floristically, the two sites were classified separately, indicating the existence of preferential groups of species between sites (Gomes et al 2011).…”

“…Mean annual rainfall is 1,520 mm and average temperature is nearly 24.8 o C (Marimon-Junior & Haridasan 2005). The park comprises approximately 500 ha, dominated by cerrado sensu stricto, composed of the cerrado rupestre and cerrado típico physiognomies (Gomes et al 2011).…”

“…However, the presumed physical limitations on the development of cerrado rupestre plants has not been confirmed by the recent studies that have compared the floristic and structural parameters of the woody communities of adjacent cerrado rupestre and cerrado típico communities, indicating that this vegetation is adapted to the conditions prevailing in these environments (Pinto et al 2009;Gomes et al 2011). Despite the floristic and structural similarities between cerrado rupestre and cerrado típico sites (Pinto et al 2009), it is still unclear whether changes in the composition of the vegetation and its structure and dynamics, are similar between these physiognomies over time.…”