Comportamento fenológico de espécies lenhosas em um cerrado sentido restrito de Brasília, DF

Abstract

-(Phenological behavior of woody species in a "cerrado" sensu stricto of Brasília, DF). In this study we followed the phenology of 19 woody species of a cerrado sensu stricto in the IBGE Ecological Reserve (15º55'06"-15º57'57" S and 47º51'22"-47º54'07" W), in Brasília, Federal District, Brazil. Phenological observations were made every fortnight between August 2000 and October 2003. The vegetation studied is a seasonal semi-deciduous wood savanna, where a hot wet season (from October through to April) is followed by a cool dry season (from May through to September). Vegetation canopy is reduced during the dry season and foliage cover reaches a minimum of 50% at the end of the dry season. Even though new leaves and flowers appear along the year, their production is intensified during the transition between the dry and wet seasons. According to the vegetative phenology, four groups were identified: four evergreen species with continuous growth, five evergreen species with seasonal growth, eight brevideciduous species and two deciduous species. The evergreen species with continuous growth produced leaves along the wet season, while the remaining groups produced leaves more intensely at the end of the dry season. Fruit maturation of autochoric and anemochoric species occurred within the dry season; zoochoric species dispersed seeds mainly during the wet season. Soil water availability seemed not to have restricted leaf production and reproduction of most species since the peak of flushing and blooming was at the end of the dry season. However, endogenous factors such as leaf longevity and internal water balance, as well as exogenous factors such as evaporative demand and irradiation seem to influence the phenological patterns observed in this vegetation.

Phanerogamic flora and vegetation of Itacolomi State Park, Minas Gerais, Brazil

“…Forest ecosystems with striking seasonality of rainfall or low soil water retention often drive high proportions of deciduous and semideciduous species in their communities (Reich & Borchet 1984, Lenza & Klink 2006. However, the fog events, common in the studied area, may favor the coexistence of species with different phenological strategies (Valim et al 2013).…”

Fenologia reprodutiva, sazonalidade e germinação de Kielmeyera regalis Saddi (Clusiaceae), espécie endêmica dos campos rupestres da Cadeia do Espinhaço, Brasil

“…Batalha & Mantovani (1999, por outro lado, observaram floração assincrônica entre Kielmeyera rubriflora e K. variabilis, que floresceram respectivamente entre abril a junho (estação seca) e de dezembro a fevereiro (estação chuvosa). Lenza & Klink (2006) A sazonalidade de floração de espécies taxonomicamente relacionadas frequentemente apresenta padrões semelhantes, mas não necessariamente ocorrem concomitantemente, sugerindo que esta fenofase não é fortemente associada à filogenia (Stevenson et al 2008). Além disso, os resultados discrepantes entre espécies similares, como observado na literatura para K. variabilis e K. coriacea, sugerem que ocorram variações na fenologia das espécies dependendo da população estudada e das condições climáticas predominantes no ano, especialmente referentes ao regime de precipitação.…”

“…A maturação lenta de frutos foi também registrada para Kielmeyera speciosa (5-7 meses) e Kielmeyera coriacea (10-12 meses) por Oliveira & Silva (1993). Lenza & Klink (2006), por outro lado, detectaram que o período de frutificação interanual de K. coriacea no cerrado sensu stricto foi curto e homogêneo, ocorrendo durante o período chuvoso (outubro e novembro). A heterogeneidade observada no período de maturação dos frutos entre as diferentes espécies de Kielmeyera pode refletir diferentes pressões seletivas bióticas ou abióticas sobre o sucesso desta fenofase.…”

“…A espécie apresenta inflorescências racemosas, flores melitófilas albo-róseas com estames de cor amarela intensa originando frutos na forma de cápsulas septicidas de onde, após a deiscência, são dispersas sementes anemocóricas aladas. Estudos recentes abordaram a fenologia (Ribeiro et al 1985;Oliveira & Sazima 1990, Oliveira & Moreira 1992Oliveira & Silva 1993;Batalha & Mantovani 1999Barros 2002;Lenza & Klink 2006;Cirne & Miranda 2008), biologia reprodutiva (Oliveira & Sazima 1990;Oliveira & Moreira 1992;Oliveira & Silva 1993) e germinação (Botelho & Carneiro 1992;Oliveira & Silva 1993;Coelho et al 1997;Cirne & Miranda 2008;Melo et al 1979;Nardoto et al 1998;Moreira & Klink 2000;Santana et al 2010) de espécies do gênero Kielmeyera que ocorrem no cerrado sensu stricto. No entanto, apesar de importante nas fisionomias rochosas dos campos rupestres dentro do bioma Cerrado, nenhuma espécie de Kielmeyera ocorrente nesses ambientes havia sido estudada.…”

Relationships between crown architecture and available irradiance in two cerrado species with different leaf phenologies

“…The woody elements of cerrado sensu stricto vegetation show two distinct functional types in terms of leaf phenology (Paula 2002, Damascos et al 2005: evergreen species, which are characterized by continuous leaf production over several months (Damascos et al 2005, Lenza & Klink 2006, retention of several leaf cohorts in their crowns throughout the year, and more intense shoot branching (Damascos et al 2005, Souza et al 2011); and deciduous species, which lose all their leaves during the dry period and demonstrate synchronous leaf fl ush at the end of the dry season. Regardless of differences in their leaf phenologies, plant species growing in seasonal environments (such as the savanna) must program leaf and shoot renewal to maximize survival and productivity (Damascos et al 2005).…”