Riparian forest potential to retain sediment and carbon evaluated by the 137Cs fallout and carbon isotopic ratio techniques

Luiz F Pires,Joseline Filippe,Klaus Reichardt,Osny O.S Bacchi,Vladia Correchel

doi:10.1590/s0001-37652009000200013

Luiz F Pires, Joseline Filippe + Show 3 more

Open Access

https://doi.org/10.1590/s0001-37652009000200013

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Abstract

Riparian forests can provide an important service for aquatic ecosystems by sequestering hillslopederived sediments. However, the width of a riparian buffer zone required to filter sediments is not yet wellunderstood. Here are used two complementary tracers to measure sediment retention. The 137Cs technique and the soil carbon isotopic ratios (delta13C) are utilized to investigate sediment deposition and erosion rates on a slope transect cultivated with sugarcane followed by a secondary riparian forest zone in Iracemápolis, State of São Paulo, Brazil. The 137Cs technique and the delta13C analysis showed that the width of a riparian vegetation in accordance to a Brazilian Environmental Law (N masculine4.771/65) was not sufficient in trapping sediments coming from agricultural lands, but indicated the importance of these forests as a conservation measure at the watershed scale. The complementary delta13C analysis together with soil morphology aspects allowed a better interpretation of the sediment redistribution along the sugarcane and riparian forest transects.

Highlights

Riparian zones are the ecotons located between aquatic and terrestrial systems, considered as key areas for the stability of the global biodiversity, serving as protection niches for wildlife, and acting as ecological corridor between forest fragments (Kajeyama et al 2002, Rodrigues and Gandolfi 2001)
The main mechanisms involved on this function are the filtering and trapping of sediments which result from erosion on upland agricultural fields
The main objective of this study is to check the efficiency of a riparian forest in trapping sediments coming from an upland sugarcane field, using the 137Cs technique aided by soil carbon isotopic ratio analysis

Summary

Introduction

Riparian zones are the ecotons located between aquatic and terrestrial systems, considered as key areas for the stability of the global biodiversity, serving as protection niches for wildlife, and acting as ecological corridor between forest fragments (Kajeyama et al 2002, Rodrigues and Gandolfi 2001). Besides their ecological function, these “buffer zones” are considered important for waterway protection, being responsible for improving surface water quality. Isolated studies carried out in Brazil indicate that the widths fixed for LPA are not always wide enough to assure the filter function for nutrients (mainly Phosphorus and Nitrogen) and sediments carried from agricultural lands (Sparovek et al 2001)

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