Phenological patterns of Rhizophora L., Avicennia L. and Laguncularia Gaertn. f. in Amazonian mangrove swamps

Abstract

The phenology of flowering and fruiting of Rhizophora mangle L., R. harrisonii Leechman, Avicennia germinans (L.) Stearn and Laguncularia racemosa (L.) Gaertn. f., were studied on Maracá Island, a continental island situated between Cape Orange (04° 20′ N) and Cape North (01° 40′ N) in the state of Amapá, North Brazil. The study was carried out during a complete annual cycle from May 1995 to April 1996. All the phenophases were produced throughout the entire year at almost all of the six studied sites. However, they presented significant peaks which characterized seasonality for all of the measured variables focused in this study. Rhizophora mangle, Avicennia germinans and Laguncularia racemosa showed significant annual variation in flowering. By contrast, Rhizophora harrisonii presented evenly distributed flowering throughout the same period of observation. The fruiting patterns showed significant variation for all sites. In general, species presented flowering peaks from August to January when temperatures were high. Fruiting peaked from October to April and occurred mostly during the wet period. Although fruiting has correlated significantly with the wet period, the correlation was less significant than that between flowering and the dry period. The flowering burst during the driest period seems to complement the strategy in which massive fruit production is obtained during the wet period. Consequently, it may ensure the development of propagules and the continued occupation of mangrove forests along the intertidal zone in the Amazon region.