Natural abundance of 13C in tropical grasses from the INPA, Instituto Nacional de Pesquisas da Amazônia, herbarium

Medina, Ernesto; Martinelli, Luiz Antônio; Barbosa, Edelcílio Marques; Victória, Reynaldo Luiz

doi:10.1590/s0100-84041999000100007

Cited by 22 publications

(14 citation statements)

References 27 publications

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“…The standard deviations of within-run organic references (bovine liver) were 0.11& for d 13 C and 0.05& for d 15 N. Unfortunately, we could not obtain enough mass to perform the isotope analysis of C 4 grass seeds from gut contents and failed to collect it in the field. We, thus, obtained isotope values of C 4 grasses in Neotropical savannahs, including the Pantanal wetlands, from the literature (Magnusson et al 1999, Medina et al 1999, Wantzen et al 2002, Bustamante et al 2004. We obtained a mean isotopic value of d 13 C = À12.86& (SD = AE0.80) and d 15 N = 2.2& (AE 0.28), and used these values in our analysis.…”

Section: Methodsmentioning

confidence: 99%

Seasonal population and individual niche dynamics in a tetra fish in the Pantanal wetlands

et al. 2017

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In seasonal tropical regions, rainfall and/or temporary floods during the wet season generally increase the abundance and diversity of food resources to many consumers as compared to the dry season. Therefore, seasonality can affect intraspecific competition and ecological opportunity, which are two important ecological mechanisms underlying population and individual niche variations. Here, we took advantage of the strong seasonality in the Pantanal wetlands to investigate how within‐ and between‐individual diet variations relate to seasonal population niche dynamics of the tetra fish Astyanax lacustris. We quantified dietary niche using gut contents and stable isotopes. Tetras had higher gut fullness and better body condition in the wet season, suggesting that competition is more intense in the dry season. The population niche was broader in the wet season due to an increase in diet divergence between individuals, in spite of potential stronger competition in the dry season. We posit that low ecological opportunity in the dry season limits the diversifying effect of intraspecific competition, constraining population niche expansion. Our results add new insights on how seasonality affects population and individual diets, indicating that intraspecific competition and ecological opportunity interact to determine temporal niche variations in seasonal environments.

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Section: Methodsmentioning

confidence: 99%

Seasonal population and individual niche dynamics in a tetra fish in the Pantanal wetlands

et al. 2017

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“…In relation to other forests, the υ 13 C of the várzea were similar to terra firma forests (Martinelli et al, 1998) and to the average reported by Hedges et al (1986) of species from the Amazon várzea. The photosynthesis process promotes distinct isotopic discrimination between plants that follow the C 3 and C 4 pathway of photosynthesis (Medina et al, 1999). The latter typically has a higher υ 13 C than the former.…”

Section: Organic Composition Of Várzea Vegetationmentioning

confidence: 99%

Inland variability of carbon–nitrogen concentrations and δ¹³C in Amazon floodplain (várzea) vegetation and sediment

Martinelli¹,

Victória²,

Camargo³

et al. 2003

Hydrological Processes

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Abstract:We analysed carbon, nitrogen and υ 13 C values in sediment sampled in the Amazon floodplains. The surface sediment samples were collected along inland transects divided according to their vegetation cover: (a) forest, where the dominant vegetation was inundation forests; (b) grass, where the dominant vegetation was grasses, mainly from Echnochloa polystachya; (c) mixed, where the vegetation changed from grasses near the river bank to forest inland. The average sediment carbon and nitrogen concentrations were significantly higher in forest samples (C D 0Ð99%, N D 0Ð12%) than in grass samples (C D 0Ð84%, N D 0Ð10%). The average sediment υ 13 C was significantly heavier in grass ( 26Ð7‰) than in forest samples ( 28Ð6‰), reflecting the isotopically heavier C 4 grasses carbon. In the forest and mixed transects inland, increases in the carbon and nitrogen concentrations were observed. At approximately 50 to 60 m from the riverbank, the concentration of carbon and nitrogen became similar to the river particulate organic carbon (POC) concentration, which is the primary floodplain sediment source. We hypothesized that this trend is caused by the deposition of carbon-and nitrogen-depleted sand-size particles in the first few metres of the floodplain, whereas the more enriched silt-clay particles are preferentially deposited far inland. In contrast to inland trends, no significant downriver trend was observed in the carbon and nitrogen concentrations. However, a downriver υ 13 C increase was observed for sediment in grass-covered areas. Based on υ 13 C values in different várzea environments, we estimated the relative contribution of riverine POC and vegetation material present in the várzea sediments under different vegetation covers. For forest sediment samples we estimated that 60% of the carbon was derived from the riverine POC and the forests provided the remaining 40%. For open areas covered with grasses we estimated that only 10% was derived from these plants, and 90% was derived from riverine POC.

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“…Characterisation of species as to photosynthetic metabolism was according to Clayton & Renvoize (1986), Renvoize (1987), Zuloaga (1987), Zuloaga & Morrone (1996), Zuloaga & Sendulsky (1988), Zuloaga et al (1993) and Medina et al (1999), besides Longhi-Wagner (personal communication).…”

Section: Methodsmentioning

confidence: 99%

A contribution to the phytogeography of Brazilian campos: an analysis based on Poaceae

Garcia¹,

Longhi-Wagner²,

Pirani

et al. 2009

Rev. bras. Bot.

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-(A contribution to the phytogeography of Brazilian campos: an analysis based on Poaceae). Twenty areas from eight Brazilian states were compared according to a list of 224 species of Poaceae. In order to determinate affi nity patterns between the areas, a binary matrix was submitted to cluster and ordination analysis. The patterns found were then faced to climate and geographic position. The scores corresponding to the areas obtained from the cluster analysis showed a strong correlation to temperature. The scores corresponding to the species suggest a gradient that associates distribution patterns to the photosynthetic pathway (C3 or C4). The current results suggest that the traditional classifi cation of the Southern American grasslands might require some modifi cation in order to be broadly applicable in the Brazilian context. Key words -Brazilian grasslands, Gramineae, multivariate analysis, South America RESUMO -(Contribuição à fi togeografi a dos campos brasileiros: uma análise baseada em Poaceae). Vinte áreas de oito estados brasileiros foram comparadas de acordo com uma lista de 224 espécies de Poaceae. Uma matriz binária foi submetida à análise de agrupamento e ordenação para determinar padrões de afi nidade entre as áreas. Os padrões obtidos foram comparados com características climáticas e posição geográfi ca. Os valores obtidos da análise de agrupamento, correspondentes às áreas, mostraram forte correlação com a temperatura. Os valores correspondentes às espécies sugerem um gradiente que associa padrão de distribuição ao tipo fotossintético (C3 ou C4). Os resultados obtidos sugerem que a classifi cação dos campos sul-americanos necessita algumas modifi cações para ser melhor aplicada ao contexto brasileiro.Palavras-chave -América do Sul, análises multivariadas, campos, Gramineae 1.Prefeitura do Município de São Paulo, Herbário Municipal.

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Natural abundance of 13C in tropical grasses from the INPA, Instituto Nacional de Pesquisas da Amazônia, herbarium

Abstract: d 13C values ranging from -13.6 to -9.5, while the remainder 40% belonged to the C3 type, with values ranging from -34.7 to -23.4. This relatively high proportion of C3 species is probably due to the high relative humidity of the sites where the species were collected.]]>

Cited by 22 publications

References 27 publications

Seasonal population and individual niche dynamics in a tetra fish in the Pantanal wetlands

Seasonal population and individual niche dynamics in a tetra fish in the Pantanal wetlands

Inland variability of carbon–nitrogen concentrations and δ¹³C in Amazon floodplain (várzea) vegetation and sediment

A contribution to the phytogeography of Brazilian campos: an analysis based on Poaceae

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Natural abundance of 13C in tropical grasses from the INPA, Instituto Nacional de Pesquisas da Amazônia, herbarium

Abstract: d 13C values ranging from -13.6 to -9.5, while the remainder 40% belonged to the C3 type, with values ranging from -34.7 to -23.4. This relatively high proportion of C3 species is probably due to the high relative humidity of the sites where the species were collected.]]>

Cited by 22 publications

References 27 publications

Seasonal population and individual niche dynamics in a tetra fish in the Pantanal wetlands

Seasonal population and individual niche dynamics in a tetra fish in the Pantanal wetlands

Inland variability of carbon–nitrogen concentrations and δ13C in Amazon floodplain (várzea) vegetation and sediment

A contribution to the phytogeography of Brazilian campos: an analysis based on Poaceae

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Abstract: d 13C values ranging from -13.6 to -9.5, while the remainder 40% belonged to the C3 type, with values ranging from -34.7 to -23.4. This relatively high proportion of C3 species is probably due to the high relative humidity of the sites where the species were collected.]]>

Inland variability of carbon–nitrogen concentrations and δ¹³C in Amazon floodplain (várzea) vegetation and sediment