Input of litter in deforested and forested areas of a tropical headstream

Carvalho, Emerson Machado de; Uieda, Virgínia Sanches

doi:10.1590/s1519-69842010005000015

Cited by 28 publications

(18 citation statements)

References 16 publications

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“…When streams are exposed to riparian forest loss and siltation, riffles tend to disappear (Rabeni & Smale, 1995), and under these conditions, stretches with slow water current tend to predominate, which probably explains the dominance of fish with affinity to slow water current in INT and DEG. Lorion & Kennedy (2009) observed the increase of detritivores and herbivores in streams without riparian vegetation in comparison to forested streams and similar results obtained in other studies indicate that this changes is probably associated to a change in the availability of food along the degradation gradient (Burcham, 1988;Bojsen & Barriga, 2002;Carvalho & Uieda (2010). Rocha et al (2009) highlighted that in deforested streams, with the predominance of cattails, detritus can be retained among roots of the macrophytes, favored by the slow water current and the large quantity of submerged organic matter.…”

Section: Discussionsupporting

confidence: 54%

From forests to cattail: how does the riparian zone influence stream fish?

et al. 2012

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The aim of this study was to verify whether taxonomic and functional composition of stream fishes vary under three different preservation conditions of riparian zone: preserved (PRE), intermediate condition (INT), and degraded (DEG). Five stream stretches representing each condition were selected. Samples were taken from each stream in three occasions during the dry seasons from 2004 to 2007. Electro fishing (PRE and INT), sieves, dip nets, and hand seines (DEG) were used according to the characteristics of each sampled site. Overall, 46 species were registered. Differences in the taxonomic and functional species composition among groups were found, following the condition of riparian zones. The ichthyofauna recorded in the PRE was typical to pristine environments, consisting of species with specialized habits, notably benthic insectivores, intolerant, and rheophilics. In the INT group, replacement of riparian forest with shrubs and/or grasses created environmental conditions which favor the occurrence of tolerant species but also harbor a residual fauna of sensitive species. DEG streams presented mostly detritivores, tolerant, small sized fishes which occupy the surface and preferred slow water flux. Changes in the species composition were represented by the occurrence and dominance of tolerant species in detriment of the more sensitive and specialist species, following the gradient of degradation in the riparian zone. Forested streams act as unique habitats to many specialized species and it can be presumable that the degradation of riparian vegetation can generate biotic homogenization which may reduce species diversity and ecosystem services.O presente estudo verificou se a composição taxonômica e funcional de peixes de riachos varia ao longo de três condições de preservação da zona ripária: preservada (PRE), preservação intermediária (INT) e degradada (DEG). Cinco riachos de cada grupo foram selecionados e amostras foram obtidas em cada riacho em três ocasiões em períodos secos de 2004 a 2007. Pesca elétrica (PRE e INT), peneiras, puçás e redes de arrasto (DEG) foram usados de acordo com as características de cada local de coleta. No geral, 46 espécies foram registradas. Foram registradas diferenças na composição taxonômica e funcional de espécies entre os grupos, seguindo o gradiente de degradação da zona ripária. A ictiofauna encontrada em PRE foi típica de ambientes prístinos, consistindo em espécies de hábitos especializados, notavelmente bentônicas, insetívoras, intolerantes e reofílicas. No grupo INT, a substituição da floresta ripária por herbáceas ou gramíneas cria condições ambientais que favorecem a ocorrência de espécies tolerantes, mas também abriga uma fauna residual de espécies sensíveis. O grupo DEG foi representado principalmente por espécies detritívoras, tolerantes e de superfície. As modificações na composição de espécies foram representadas pela ocorrência e dominância de espécies tolerantes em detrimento da redução/eliminação daquelas mais sensíveis e especializadas, acompanhando o grad...

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Section: Discussionsupporting

confidence: 54%

From forests to cattail: how does the riparian zone influence stream fish?

et al. 2012

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“…Previous studies done in the same area confirmed a spatial and seasonal variation of litter input (Carvalho and Uieda, 2010), litter mass loss (Carvalho and Uieda, 2009b) and invertebrate diet (Carvalho and Uieda, 2009a). It needs to be reinforced that, although for a better spatial and seasonal analysis it will be recommended to evaluate more than one stream and year, this work is part of a broad study of the dynamic of the leaf litter input and process, what logistically could be done only in a small spatial and temporal scale.…”

Section: Introductionsupporting

confidence: 66%

“…In the present study, a distinct pattern of seasonality was found and the composition of most representative groups varied in each season. The dry season was characterized by a high predominance of Chironomidae, maybe related to an increase of organic matter deposition in the stream channel in function of the lower values of rainfall and discharge during this season (see Carvalho and Uieda, 2010). On the other hand, the higher values of diversity and evenness found for wet season data may be related to a less dominance of Chironomidae.…”

Section: Discussionmentioning

confidence: 99%

“…The removal of riparian vegetation was clearly reflected in the low contribution of leaf litter to the stream (Carvalho and Uieda, 2010) and in the increase of light incidence (Rodrigues and Leitão-Filho, 2001). Those modifications can have a potential effect on the invertebrate community structure, with a reduction of the shredder's functional group and an increase of primary consumers (Carvalho and Uieda, 2009a).…”

Section: Introductionmentioning

confidence: 99%

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Experimental manipulation of leaf litter colonization by aquatic invertebrates in a third order tropical stream

2015

Braz. J. Biol.

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Through a manipulative experiment, the colonization of leaf litter by invertebrates was investigated in two sections of a tropical stream (spatial scale) that differed in function of the canopy cover, one with the presence (closed area) and another without riparian vegetation (open area), during one month of the dry and one of the wet season (temporal scale). The work aimed to verify differences related to four variables: season, canopy cover, leaf type and leaf condition. Litter bags containing arboreal and herbaceous leaves (leaf type variable), non-conditioned and preconditioned (leaf condition variable) were placed at the bottom of the stream in each area (canopy cover variable) and season (dry and wet), and removed after 13-day colonization. The analysis of the remaining litter dry mass per leaf bag emphasizes differences related mainly to seasonality, canopy cover and leaf type, although leaf condition was also important when combined with those three factors. Comparing the abundance of invertebrates per treatment, there was a tendency of high predominance of Chironomidae during the dry season and greater taxa diversity and evenness during the wet season, when the water flow increase could alter the availability of microhabitats for local fauna. Even though canopy cover alone was not a significant source of variation in the abundance of invertebrates, the results showed a tendency of a combined effect of canopy cover with seasonality and leaf condition.Keywords: aquatic insects, leaf breakdown, headwater streams, seasonal variation, spatial variation. Manipulação experimental da colonização de detritos foliares por invertebrados aquáticos em um riacho tropical de 3ª ordem ResumoAtravés de um experimento de manipulação, a colonização de detritos foliares por invertebrados foi analisada em duas seções de um riacho tropical (escala espacial), que diferem em função da cobertura do dossel , um com a presença (área fechada) e outro sem vegetação ciliar (área aberta), durante um mês da estação seca e um da chuvosa (escala temporal). O trabalho teve como objetivo verificar as diferenças relacionadas a quatro variáveis: estação, cobertura vegetal, tipo e condição da folha. Sacos de náilon contendo folhas de uma planta arbórea e uma herbácea (tipo folha), não-condicionadas e pré-condicionadas (condição da folha) foram colocadas em cada área e estação do ano e removidos após 13 dias de colonização. A análise da massa seca remanescente dos detritos enfatizou diferenças relacionadas principalmente à sazonalidade, cobertura do dossel e tipo folha, embora a condição da folha também tenha sido importante quando combinado com esses três fatores. Comparando a abundância de invertebrados por tratamento, houve uma tendência de predominância de Chironomidae durante a estação seca e maior diversidade e equidade durante a estação chuvosa, quando o aumento do fluxo de água pode alterar a disponibilidade de micro-habitats para a fauna local. Apesar de cobertura do dossel sozinha não ter sido uma importante fonte de variaçã...

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“…It is expected that this condition would lead to the coexistence of species with broad food spectra and low feeding-niche overlap. Moreover, in streams where the structural characteristics of the channel and surroundings are preserved, there is greater availability of food from different sources (autochthonous and allochthonous) (Carvalho & Uieda, 2010;Cruz et al, 2013). In view of the morphological potential of each species to exploit these food sources, this greater availability may lead to unique or poorly understood patterns of trophic structure.…”

Section: Introductionmentioning

confidence: 99%

Diet and ecomorphological relationships of an endemic, species-poor fish assemblage in a stream in the Iguaçu National Park

Neves¹,

Delariva

Wolff

2015

Neotrop. ichthyol.

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This study investigated the morphological and dietary relationships of the fish assemblage in a stream with an endemic fauna and low species richness. The ichthyofauna was sampled quarterly from September 2011 to July 2012, through the electrofishing technique. The stomach contents of 419 individuals belonging to seven species were analyzed by the volumetric method, and the ecomorphological traits of 30 specimens of each species were estimated. The main food items consumed were detritus, aquatic and terrestrial insects, and other aquatic invertebrates. We observed low levels of trophic niche breadth and diet overlap between most species. The PCA scores indicated the occurrence of three ecomorphotypes. PCA axis 1 segregated at one extreme, species with dorsoventrally depressed bodies, longer caudal peduncles, and welldeveloped swimming fins; and at the other extreme, species with compressed bodies and peduncles, and relatively larger eyes and anal fins. PCA axis 2 segregated species with elongated bodies and ventrally oblique mouths. The partial Mantel test revealed a significant correlation between diet and morphology, indicating independence from the phylogeny. The patterns observed suggest that the low richness did not result in a broadening of the species' trophic niches, or in the absence of some of the main ecomorphotypes expected.Este estudo teve como objetivos investigar as relações morfológicas e alimentares de uma assembleia de peixes com fauna endêmica e de baixa riqueza de espécies. Os peixes foram amostrados trimestralmente entre setembro de 2011 a julho de 2012, através da técnica da pesca elétrica. Foram obtidas as medidas morfométricas que possibilitaram os cálculos dos índices ecomorfológicos e analisados os conteúdos estomacais de 419 indivíduos, pertencentes a sete espécies, através do método volumétrico. Os principais itens alimentares consumidos pela assembleia de peixes foram detrito, insetos aquáticos e terrestres e outros invertebrados aquáticos. Observou-se baixos valores de amplitude de nicho trófico e de sobreposição alimentar entre a maioria das espécies. Os escores da PCA, indicaram a ocorrência de três ecomorfotipos. O eixo CP1 segregou em um extremo espécies com corpo deprimido dorso-ventralmente, pedúnculo caudal longo e as nadadeiras desenvolvidas, enquanto no outro extremo, espécies com corpos e pedúnculos comprimidos, área dos olhos e das nadadeiras anais relativamente maiores. Por outro lado, o eixo CP2 segregou espécies com corpos mais alongados, bocas ventralmente oblíquas. Através do Teste de Mantel verificou-se relação significativa entre a dieta e a morfologia. Assim, os principais padrões tróficos e ecomorfológicos verificados sugerem que a baixa riqueza, não repercutiu no alargamento do nicho trófico das espécies ou na inexistência de algum dos principais grupos ecomorfológicos.

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Input of litter in deforested and forested areas of a tropical headstream

Cited by 28 publications

References 16 publications

From forests to cattail: how does the riparian zone influence stream fish?

From forests to cattail: how does the riparian zone influence stream fish?

Experimental manipulation of leaf litter colonization by aquatic invertebrates in a third order tropical stream

Diet and ecomorphological relationships of an endemic, species-poor fish assemblage in a stream in the Iguaçu National Park

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