Large Woody Debris Input and Its Influence on Channel Structure in Agricultural Lands of Southeast Brazil

Autor(es)

de Paula, Felipe Rossetti ^[1] ; de Barros Ferraz, Silvio Frosini ^[2] ; Gerhard, Pedro ^[3] ; Vettorazzi, Carlos Alberto ^[1] ; Ferreira, Anderson ^[4]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Luiz Queiroz Coll Agr, Dept Biosyst, BR-13418900 Piracicaba, SP - Brazil

^[2] Univ Sao Paulo, ESALQ, Dept Forest Sci, Luiz Queiroz Coll Agr, Depto Ciencias Florestais 1, BR-13418900 Piracicaba, SP - Brazil

^[3] Brazilian Agr Res Corp, Nat Resources Management Themat Grp, Belem, PA - Brazil

^[4] Univ Sao Paulo, Nucl Energy Ctr Agr, Isotop Ecol Lab, BR-13418900 Piracicaba, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Environmental Management; v. 48, n. 4, p. 750-763, OCT 2011.
• Citações Web of Science: 8

Resumo

Riparian forests are important for the structure and functioning of stream ecosystems, providing structural components such as large woody debris (LWD). Changes in these forests will cause modifications in the LWD input to streams, affecting their structure. In order to assess the influence of riparian forests changes in LWD supply, 15 catchments (third and fourth order) with riparian forests at different conservation levels were selected for sampling. In each catchment we quantified the abundance, volume and diameter of LWD in stream channels; the number, area and volume of pools formed by LWD and basal area and tree diameter of riparian forest. We found that riparian forests were at a secondary successional stage with predominantly young trees (diameter at breast height < 10 cm) in all studied streams. Results showed that basal area and diameter of riparian forest differed between the stream groups (forested and non-forested), but tree density did not differ between groups. Differences were also observed in LWD abundance, volume, frequency of LWD pools with subunits and area and volume of LWD pools. LWD diameter, LWD that form pools diameter and frequency of LWD pools without subunits did not differ between stream groups. Regression analyses showed that LWD abundance and volume, and frequency of LWD pools (with and without subunits) were positively related with the proportion of riparian forest. LWD diameter was not correlated to riparian tree diameter. The frequency of LWD pools was correlated to the abundance and volume of LWD, but characteristics of these pools (area and volume) were not correlated to the diameter of LWD that formed the pools. These results show that alterations in riparian forest cause modifications in the LWD abundance and volume in the stream channel, affecting mainly the structural complexity of these ecosystems (reduction in the number and structural characteristics of LWD pools). Our results also demonstrate that riparian forest conservation actions must consider not only its extension, but also successional stage to guarantee the quantity and quality of LWD necessary to enable the structuring of stream channels. (AU)

• Processo FAPESP: 03/10505-0 - Ecologia alimentar e ecomorfologia de tetragonopterinae (osteichtyes, characiformes, characidae) e suas interacoes com a estrutura da vegetacao riparia, em riachos da bacia do rio passa-cinco, sp.
• Beneficiário: Anderson Ferreira
• Linha de fomento: Bolsas no Brasil - Doutorado
• Processo FAPESP: 06/00797-2 - Influencia da paisagem na entrada de materia vegetal (troncos) e na estrutura de canais em microbacias da bacia do rio corumbatai, sp.
• Beneficiário: Felipe Rossetti de Paula
• Linha de fomento: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 06/04723-3 - Influência da paisagem na entrada de matéria vegetal (troncos) e na estrutura de canais em microbacias da Bacia do Rio Corumbataí, SP
• Beneficiário: Silvio Frosini de Barros Ferraz
• Linha de fomento: Auxílio à Pesquisa - Regular