Nutritional quality and calorific value of Amazonian forest litter

Abstract

A study on the nutritional quality of litter from an Amazon terra firme forest was carried out to supplement quantitative data on litter production previously published by KLINGE and RODRIGUES (1968). Analyses for the following constituents were carried out: cell-wall and non cell-wall fractions, crude protein, total mineral ash, polyphenols, and caloric values. Reasons are given for choosing these variables. Mineral ash and protein values were very low, whilst cell-wall fractions, which are a measure of the amount of undigestible material, were high, as were caloric values. Polyphenols were also relatively high. These factors together indicate that the litter is a very low grade forage. Amazon leaf litter has high caloric values compared with published figures from other tropical forests. The following hypothesis was offered to explain these high values: as mineral nutrients are severely limiting in this ecosystem, not all the products of photosynthesis can be channeled into plant growth. Large proportions of these photosynthetic products are therefore probably accumulated in the leaves as reduced high energy compounds such as waxes, resins etc. Available data do in fact indicate that primary production is relatively low. The low quality forage which the leaf litter offers may be a contributing factor to the low animal biomass of the Amazon forests