Reproductive phenology of an herbaceous-subshrub layer of a Savannah (Campo Sujo) in the Cerrado Biosphere Reserve I, Brazil

Abstract

The objective of this study was to analyse the phenological events in the herbaceous and subshrub layer in relation to rainfall and the dispersion syndromes of the species at a Campo Sujo community in the Água Limpa Farm (FAL), Brasília-DF. Campo Sujo is a grassland Savannah with a few scattered shrubs and small trees. The climate is Aw by Köppen classification with a mean annual precipitation of 1500 mm. Herbaceus species with three to ten individuals were monitored totalling 519 individuals of 61 species. The individuals were observed quarterly from October 1999 to February 2001. An accidental fire happened in the area two months before the beginning of this study and stimulated flowering and fruiting of the studied species. Flowering at the community level was distributed all over the study period with a concentration of flowering species in the rainy season. The pattern of fruiting was similar to the flowering, with most species maturing their diaspore from the middle to the end of the rainy season. The correlation between anemochoric species producing mature fruits and precipitation was significant and inverse. Anemochoric and autochoric species are dominant at the herbaceous-subshrub layer of the Campo Sujo and they determine the phenological pattern of the community.Keywords: phenology, dispersion syndromes, anemochoric, herbaceous layer, Cerrado. Fenologia reprodutiva da camada herbácea e subarbustiva de savana (Campo Sujo) na Reserva da Biosfera do Cerrado I, BrasilResumo O objetivo deste estudo foi analisar os eventos fenológicos na camada herbácea subarbustiva em relação à precipitação e às síndromes de dispersão das espécies em uma comunidade de Campo Sujo na Fazenda Água Limpa (FAL), Brasília-DF. O Campo Sujo é uma savana predominantemente herbácea com poucos arbustos e pequenas árvores. O clima da região é do tipo Aw, segundo a classificação de Köppen, com uma precipitação média anual de 1500 mm. Foram selecionadas as espécies que possuíam de 3 a 10 indivíduos, resultando em 61 espécies e 519 indivíduos amostrados. Os indivíduos foram observados quinzenalmente de outubro de 1999 a fevereiro de 2001. O fogo ocorrido na área dois meses antes do início do estudo estimulou a floração e a frutificação das espécies amostradas. A floração na comunidade apresentou-se distribuída por todo o período estudado com concentração de espécies florescendo na estação chuvosa. A produção de frutos foi similar, com a maioria das espécies amadurecendo seus diásporos do meio para o final da estação chuvosa. A correlação entre as espécies anemocóricas produzindo frutos maduros e a precipitação foi significativa e inversa. As espécies anemocóricas e autocóricas são dominantes na camada herbácea subarbustiva de Campo Sujo e determinam o padrão fenológico da comunidade.Palavras-chave: fenologia, síndromes de dispersão, anemocórico, camada herbácea, Cerrado.

Vascular flora in dry-shrub and wet grassland Cerrado seven years after a fire, Federal District, Brazil

“…The predominance of anemochoric dispersion over time is associated to the physiognomic types of the sites, which are open grasslands, and the dominance of herbaceous species, a pattern observed in other studies on the Cerrado (Batalha et al 1997;Batalha and Mantovani 2000;Tannus et al 2006), and in this dry-shrub grassland seven years ago (Munhoz and Felfili 2007b), but increased zoochory may be another factor to confirm the influence of the absence of fire in the changes found in the landscape over time, especially in the ALF wet grassland, where after years of fire protection a greater density of chamaephytes and phanerophytes was verified. The prevalence of the zoochoric dispersal syndrome in different environments is associated with the dominance of woody species (phanerophytes and chamaephytes), as occurs in the cerrado sensu stricto and forest habitats (Batalha and Mantovani 2000;Kinoshita et al 2006;Tannus and Assis 2006;Ishara and Maimoni-Rodella 2011).…”

Post-fire reproduction of herbs at a savanna-gallery forest boundary in Distrito Federal, Brazil

“…The change in the observation interval of the reproductive events (from fortnightly to bimonthly) might have subsampled the community phenological patterns, but our results agree with Munhoz and Felfili (2007) and Tannus et al (2006), which indicated a peak of flowering for the herbaceous community at the end of rainy season. In the border, the number of species with flowers and/or fruits was greater in the middle of the rainy season, therefore earlier than in savanna, that had its reproductive peak in the end of the rainy season.…”

“…The effects of burning on reproduction may be more complex though. Some studies conducted in Cerrado areas have shown that herbaceous species are able to flower and fruit shortly after fires (Coutinho, 1976;César, 1980;Munhoz and Felfili, 2007); while in a grassland in the South of Brazil, Fidelis and Blanco (2014) showed some species only reproducing more than one year after fire.…”

Evolution of seed dispersal in the Cerrado biome: ecological and phylogenetic considerations

“…As a vegetation that is susceptible and conditioned by fire (Coutinho 1990), especially savannas and grasslands, this is another factor that can play selective pressure on fruit types in Cerrado. It has been demonstrated that fire increases nutrient cycling on soil and stimulates flowering and thus seed production in some Cerrado plants, such as Poaceae, Cyperaceae and Bromeliaceae (Munhoz & Felfili 2007), and that high temperatures caused by fire can also accelerate fruit drying and seed release and higher germinability in some species, like Kielmeyera coriacea, which have a coriaceous dry fruit (Cirne & Miranda 2008;Zaidan & Carreira 2008). However, there is still little information available about the fire effects on fruit production and germination of the Cerrado species, especially in woody plants (Palermo & Miranda 2012).…”