Litter Fall of Avicennia germinans L. in a One-Year Cycle in a Mudflat at the Laguna de Mecoacan, Tabasco, Mexico

Abstract

The fall of four morphological components of Avicennia germinans L. was measured at monthly intervals along a transect in a monospecific mangrove near the inlet of the Laguna de MecoacAn, Tabasco, Mexico. Estimated mean total annual litter fall was 614.4 g.m-2 yr-1. Seasonal fluctuations of mean water level, insolation, temperature and evaporation were highly intercorrelated and were summarized in a principal component axis that explains 82 percent of their variability. The results suggest that litter fall in A. germinans responds to the environmental variables already mentioned but is statistically independent from local rainfall. Each litter component (leaves, flowers and reproductive parts, branches and woody parts, and propagules) shows a distinctive sequence, and significant correlations were obtained when comparing the principal component axis against leaf and propagule fall. Phenologic variation in litter fall as an adaptive response to environmental changes is discussed. DESCRIPTIONS OF THE PHENOLOGY OF MANGAL WOODY SPECIES have been done in Florida (Gill and Tomlinson 1971, Pool et al. 1975); Thailand (Christensen 1978, WiumAndersen and Christensen 1978); Malaysia (Gong et al. 1980); Veracruz, Mexico (Rico 1979); and northeastern Australia (Williams et al. 1981). Emphasis, however, has been given in most cases to the whole community, or to species of Rhizophora. Recent reports have made clear that there are different species responses to the mangal environment and dimate (e.g., Wium-Andersen 1981, Williams et al. 1981, Snedaker and Brown 1982). This paper describes the annual phenological variations in litter fall of Avicennia germinans L. in a mudflat environment and analyzes their relation to environmental parameters, such as temperature, insolation, water level, and rainfall.