Input of litter in deforested and forested areas of a tropical headstream

Em Carvalho,Vs Uieda

doi:10.1590/s1519-69842010005000015

Abstract

Riparian vegetation is the main source of leaves and the main energy source for low order streams. Therefore, changes in its composition affect the structure and processes in streams. We studied the contribution of the riparian vegetation by analysing the annual input of litter in deforested and forested areas of a tropical stream. The lateral, vertical (aerial) and horizontal (drift) litter inputs were analysed separately. The lateral input differed significantly between the two areas and included mostly fallen dry leaves. The vertical input, represented mainly by fallen dry leaves, occurred only in the forested area. The drift transport of litter was not significantly different between the deforested and forested areas and the input was composed mostly by CPOM. The removal of the native forest was clearly reflected in the low contribution of leaf litter in the deforested area.

Highlights

Every year streams receive a large amount of litter dry mass per square metre (Elosegi and Pozo, 2005)
In temperate deciduous forests, autumn litter inputs may be as high as 73% of annual amounts (e.g. Abelho and Graça, 1998)
Rainfall registered in the Ribeirão da Quinta stream showed two well-defined seasons, with the highest values of litter input during the end of the dry season (September), coincident with the lowest value of discharge

Summary

Introduction

Every year streams receive a large amount of litter dry mass per square metre (Elosegi and Pozo, 2005). A large part of these detritus input consists of leaves from riparian vegetation (Abelho, 2001; Elosegi and Pozo, 2005). Headwater streams are influenced by riparian vegetation which reduces autotrophic production by shading and supplies energy in the form of vegetal matter of allochthonous origin (Vannote et al, 1980; Abelho, 2001; Graça, 2001; Graça and Canhoto, 2006; Uieda and Motta, 2007). A qualitative and quantitative change in the riparian forest affects the litter input to streams and can modify the structure of the whole biotic community (Afonso et al, 2000; Graça, 2001).

Objectives

Methods

Results

Conclusion