Effect of seasonal flooding cycle on litterfall production in alluvial rainforest on the middle Xingu River (Amazon basin, Brazil)

Abstract

The assumption for this study was that litterfall in floodplain environments of the middle Xingu river follows a pattern of seasonal variation. According to this view, litterfall production (total and fractions) was estimated in four alluvial rainforest sites on the middle Xingu River over an annual cycle, and examined the effect of seasonal flooding cycle. The sites included two marginal flooded forests of insular lakes (Ilha Grande and Pimentel) and two flooded forests on the banks of the Xingu itself (Boa Esperança and Arroz Cru). Total litterfall correlated with rainfall and river levels, but whereas the leaf and fruit fractions followed this general pattern, the flower fraction presented an inverse pattern, peaking in the dry season. The litterfall patterns recorded in the present study were consistent with those recorded at other Amazonian sites, and in some other tropical ecosystems.Keywords: alluvial rainforest, fractions of litter production, middle Xingu River.Efeito da variação da inundação sazonal na produção de serrapilheira numa floresta aluvial do médio Rio Xingu (bacia do Amazonas, Brasil) ResumoO pressuposto para este estudo foi que a produção de serrapilheira nos ambientes inundáveis do médio rio Xingu, segue um padrão de variação sazonal. Assim, se quantificou durante um ciclo anual a produção de serapilheira total e de suas frações, e se indagou a correlação entre o regime do nível do rio e a produção de serapilheira. Quatro ambientes de floresta ombrófila aluvial foram estudados: duas florestas inundáveis de lagoas insulares (Ilha Grande e Pimentel) e dois ambientes de floresta marginal no canal principal do rio Xingu (Boa Esperança e Arroz Cru). A produção de serapilheira total nos quatro ambientes mostrou um padrão sincrônico com a variação do nível do rio e com a inundação das áreas marginais. Por sua vez, foi evidente um aumento da produção de frutos durante a inundação local e de forma inversa uma maior produção de flores com o regime de seca. Os padrões registrados para os componentes de serapilheira do médio rio Xingu, confirmam os achados para outros ambientes amazônicos e tropicais.Palavras-chave: floresta ombrófila aluvial, produção de serrapilheira, médio Rio Xingu.

Biochar amendment did not influence the growth of two tree plantations on nutrient‐depleted Ultisols in the south Ecuadorian Amazon region

“…The finding that G. arborea had a substantially higher litterfall during the dry than the rainy season has been reported for other seasonal tropical forests (Borchert et al, 2002;Camargo et al, 2015;Tonin et al, 2017;Wieder & Wright, 1995;Wilcke & Lilienfein, 2002). The increased litterfall during the dry season is thought to be a response to water stress because fewer leaves reduce water losses by transpiration (Borchert et al, 2002).…”

Metagenome Sequencing of Prokaryotic Microbiota Collected from Rivers in the Upper Amazon Basin

“…There are two well-established seasons (dry and flood) as described in references 6–8. These complex ecosystems work actively in carbon budget processes (9–11).…”

Flooding water and society

“…This idea was initially produced through the success of the hydrological cycle, an abstract representation that, as Linton has explained, is assumed to be the actual way in which water moves (Linton, ). While floods, which can be a seasonal and cyclical occurrence (Camargo, Giarrizzo, & Ajs, ; Parolin, Lucas, Piedade, & Wittmann, ), seem to be at first a good example of iteration, they are increasingly one of the most abrupt and unexpected manifestations of rapid environmental transformation. Far from being a mere step in the unperturbed cycle of nature, floods are increasingly disruptive and sudden events that force us to question the stability of our cyclical representations of water.…”