Mangrove litter production and seasonality of dominant species in Zanzibar, Tanzania

Abstract

This study is aimed at examining the litter production and seasonality of Avicennia marina, Bruguiera gymnorhiza, and Rhizophora mucronata. Litter was collected using nylon litter traps of 1 mm2 mesh size in the Uzi-Nyeke mixed mangroves, Zanzibar, over a period of 2 years. Contents were sorted, dried, weighed, and the average daily litter production for each component was calculated. A distinct seasonality and species variation were found in all mangrove litter components. The average annual litterfall rate was higher in B. gymnorhiza, followed by R. mucronata and A. marina (3.0, 2.8, and 2.0 ton dry wt. ha^-1year^–1 respectively). Leaf fraction was the main component of litter in all species, but fruit and flower for R. mucronata also had a considerable contribution to the total litterfall. The presented patterns of litter production are associated with average temperature and wind speed which are both strongly correlated with litter seasonality. Our data contributes to the body of knowledge on  patterns of litter production and the ecological integrity of mangrove forests in Zanzibar.

Keywords: Litterfall, mangrove species, seasonal patterns