A Influência Do Pulso De Inundação Na Ecolimnologia De Baías Pantaneiras: Um Estudo Na Dinâmica De Invertebrados Aquáticos

Abstract

RESUMOEste estudo se propôs relacionar as variáveis ambientais com a biota presente em duas baías do Pantanal Matogrossense, próximas à cidade de Cáceres-MT. Foram coletados dados de variáveis bióticas e abióticas da água em seis pontos de amostragem durante um ano de pesquisa, compreendendo os quatro períodos hidrológicos do Pantanal. Foi encontrada rica fauna de invertebrados aquáticos associados à macrófitas, tendo a Classe Insecta maior representatividade. As variáveis oxigênio dissolvido, transparência e profundidade apresentaram diferenças estatisticamente significativas entre os períodos hidrológicos. Os grupos Nematoda, Ostracoda, Decapoda, Chironomidae, Dityscidae e Copepoda estiveram significativamente correlacionados com as variáveis estudadas. Estes resultados podem indicar que as variáveis limnológicas exerceram influência na comunidade de invertebrados aquáticos e que modificações na qualidade da água podem resultar em uma alteração na microbiota, a qual exerce papel fundamental no fluxo de matéria e ciclagem de nutrientes dentro de um ecossistema aquático. Palavras-chave: Variáveis limnológicas. Invertebrados bentônicos. Pantanal Matogrossense. ABSTRACTThis study aimed to compare the environmental variables with this biota in two bays in the Pantanal near the city of Cáceres-MT. Data of biotic and abiotic variables of the water sampling were analyzed on six sampling points for one year survey comprising four Pantanal hydrological periods. Rich invertebrate fauna associated with aquatic macrophytes were found; with the Class Insecta is

Characterization of the Biotic (Macrophytes and Macroinvertebrates) and Abiotic Factors of Pantanal Ponds in the Miranda River Floodplain

“…This shows the influence of flood flow on the distribution of macrophytes and consequently on invertebrate colonization. Data from the literature confirm that the composition and abundance of invertebrates present in the macrophyte stands are determined by the amplitude of the flood pulse (Eaton 2006, Oliveira-Junior et al 2013.…”

“…These variations in pH can be explained mainly by a natural phenomenon known as "decoada" or "dequada" (Esteves 1998). This event is characterized by the natural alteration of water quality during the hydrologic phase of flood, whose intensity varies according to the climate and the annual flood patterns (Oliveira-Junior et al 2013). Besides, water losses due to evapotranspiration of macrophytes must exceed the intakes, especially during the dry season, leading to an increase in pH and alkalinity (Eaton 2006).…”

“…The variation of the physical and chemical parameters observed between the ponds, mainly between the values of dissolved oxygen, electrical conductivity, water turbidity, chlorophyll a and pheophytin-a can be explained both by the permanent and intermittent characteristics of the ponds (Silva & Carniello 2007) and by the concentration of organic matter at the bottom, which led to the depletion of dissolved oxygen in the benthic zone. Besides the senescence of many aquatic macrophytes (Oliveira-Junior et al 2013), the leaching of the terrestrial litter raises the organic material inside the system. However, many Pantanal fauna and flora communities are adapted to such seasonal and temporal variations, which ultimately determine many biological patterns.…”

“…They also provide habitat for associations of periphytic algae and nitrogen-fixing bacteria (Diniz et al 2018). In this aquatic environment, invertebrates play a role in the flow of energy and matter, participating in the process of decomposition of organic matter, reducing the size of the particles and serving as food for several species of fish and other animals (Eaton 2006, Silva et al 2009, Oliveira-Junior et al 2013, Diniz et al 2018.…”

“…Despite the great importance of the Pantanal complex for the diversity of fauna and flora, basic ecological information for most invertebrates is still incipient (Eaton 2006). Information on hydrological changes and invertebrates are valuable to understand the structure and dynamics of limnic communities and for records of ecological processes resulting from changes caused by flood (Oliveira-Junior et al 2013). The lack of studies aiming the conservation of invertebrates in Pantanal occurs part due to the extremely high species richness, the enormous abundance of some groups, the taxonomic difficulties mainly of the hyperdiver groups, the anthropic alterations of the habitat as well as due to the lack of resources for conservation programs (MMA 2007).…”