Produtividade primÃria em bosque de franja e bacia no manguezal do Rio Ariquindà ( Tamandarà â Pernambuco, Brasil )




This work was developed with the objective to measure the primary productivity in mangrove swamps at the headwater and river mouth of the Ariquindà river estuary (TamandarÃ-Pernambuco, Brasil) distant 120 km from Recife considering the dry and wet season. Litter production in monoespecific stands of Rhizophora mangle and Laguncularia racemosa was determined during a twelve months period (September 2007 to August 2008). Thirty two litter traps of 0,25 m were spread among four different sites suspended under mangrove trees above the maximum tidal elevation. Litter fall was collected monthly and the material was sorted into six categories; leaves, stipules, fruits, flowers, wood and miscellaneous. The collected material was dried at 75ÂC until it reached constant weight. Annual total litter fall ranged from 7,04 t.ha-1.yr-1 in a monoespecific L. racemosa basin mangrove forest (station AF3) to 12,28 t.ha-1.yr-1. in a monoespecific R. mangle fringe stand (station AF1). Intermediary values of annual litter fall production were found in the stands at the headwaters of the Ariquindà river (stations AN1 and AN3); 11,85 and 8,46 t.ha-1.yr-1, respectively. Leaves were the main component representing about 80% of litter fall production in all stands. Stipules, wood, fruits, flowers and miscellaneous components followed in importance. Fringe stands (AN1 and AF1) had peak production in February. Basin stands (AN3 and AF3) peaked later in April. The AF3 station, represented by L. racemosa evidenced a strong seasonality in propagule production peaking in April. During the wet season there was a sharp increase in wood and miscellaneous production. The greater amount of litter fall in the beginning of wet season reflects a reproductive strategy found in a several mangrove forests around the world. The reproductive components it was the only to demonstrate related with rainfall


serapilheira e rio ariquindà oceanografia produtividade primÃria mangrove litter fall ariquindà river primary productivity manguezal

Documentos Relacionados