Leaf Breakdown in a Tropical Stream

Abstract

The objectives of this study were to investigate leaf breakdown in two reaches of different magnitudes, one of a 3 rd (closed riparian vegetation) order and the other of a 4 th (open riparian vegetation) order, in a tropical stream and to assess the colonization of invertebrates and microorganisms during the processing of detritus. We observed that the detritus in a reach of 4 th order decomposed 2.4 times faster than the detritus in a reach of 3 rd order, in which, we observed that nitrate concentration and water velocity were greater. This study showed that the chemical composition of detritus does not appear to be important in evaluating leaf breakdown. However, it was shown to be important to biological colonization. The invertebrate community appeared not to have been structured by the decomposition process, but instead by the degradative ecological succession process. With regards to biological colonization, we observed that the density of bacteria in the initial stages was more important while fungi appeared more in the intermediate and final stages.

Colonization by oligochaetes (Annelida: Clitellata) in decomposing leaves ofEichhornia azurea(SW.) Kunth (Pontederiaceae) in a neotropical lentic system

“…A negative correlation between remaining dry leaf mass and invertebrate density was also described by Gonc¸alves et al (2006Gonc¸alves et al ( , 2007 and Moretti et al (2007). The increasing density during the experiment can be a response to the greater availability of food (Smock and Stoneburner, 1980).…”

Fungos associados ao processo de decomposição foliar: 2 anos de estudo

“…No laboratório, as folhas foram removidas dos sacos e lavadas individualmente com água destilada. Destas folhas foram retirados 2 conjuntos de discos (5 unidades de discos com 2 cm de diâmetro) sendo que um conjunto foi utilizado para análise de peso seco livre de cinzas (AFDM) para quantificação da matéria orgânica foliar [10], e o outro conjunto para realizar as contagens fúngicas.…”

Use of Food Resources by Detritivorous Fish in Flood-Plains: A Synthesis

“…The conditioning or catabolism consists in the colonization of the organic matter by fungi and bacteria responsible for the mineralization of the decomposing material (Gonçalves et al, 2006). Thus, this stage prepares the organic matter be consumed by the invertebrate organisms, while the detritus fragmentation enlarges the surface susceptible to the action of microorganisms, resulting in the material degradation (Cunha-Santino and Bianchini Jr, 2006).…”