Riparian vegetation provides the nutrient and energy input that maintains the metabolism and biodiversity in tropical headwater streams. In the present study, it was hypothesised that ~30% of riparian plant species contribute over 70% of coarse particulate organic matter and, because tropical plants are perennial and semi-deciduous, it was expected that leaf fall would occur year round. The aims of the present study were to evaluate the composition and structure of the plant riparian zone and the input and associated benthic stock of organic matter. The riparian vegetation was composed of 99 taxa. The most abundant plant species were Tapirira obtusa, Sclerolobium rugosum, Croton urucurana, Byrsonima sp. and Inga sp. The input and benthic stock showed a seasonal pattern, with higher values recorded at the end of the dry season and at the beginning of tropical storms. The biomass contributed monthly by the vegetation ranged from 28 ± 6 g m–2 to 38 ± 11 g m–2, and the mean monthly benthic standing stock was 138 ± 57 g m–2. The results illustrate the importance of riparian vegetation as an energy source to tropical streams and how individual plant species contribute to organic matter inputs in these ecosystems.
Aquatic plants have great influence on the structure and dynamics of aquatic ecosystems, thereby contributing considerably to biodiversity. In Brazil, knowledge of the biodiversity of aquatic macroflora is still limited. We present a checklist of aquatic macrophytes occurring in the northeastern region of Brazil through a bibliographic search. We recorded a total of 412 species, 217 genera and 72 families. The most representative families were Cyperaceae (70 species), Poaceae (38), Fabaceae (27) and Asteraceae (20). The States with highest number of species were Pernambuco (370), Bahia (360), Ceará (267) and Paraíba (261). The best-represented life forms were amphibious (193 species) and emergent (100). The aquatic flora of Northeastern Brazil exhibits high species richness; however, there is a scarcity of records of aquatic macrophytes for the States of Alagoas, Rio Grande do Norte, Maranhão, Sergipe and Piauí.
Evaluation of the eff ects of fl ooding on seedling recruitment from seed banks helps in understanding vegetation regeneration in fl oodplains. We studied the eff ects of simulated fl ooding on richness and abundance of, and temporal variation in, seedling recruitment from the soil seed bank of a fl oodable savanna of the Pantanal wetland, under two conditions: 1) Post-fl ood = inundated for 30 days followed by irrigation; 2) Non-fl ooded = only irrigated. We recorded emerged seedlings biweekly for 120 days and found a total of 124 species for the two treatments, the most abundant species were annual herbs (e.g., Richardia grandifl ora and Euploca procumbens) and annual graminoids (e.g., Digitaria ciliaris and Cyperus haspan). Flooding positively infl uenced seedling richness and abundance, while seedling emergence from the non-fl ooded soil was slower, but continued during all periods. Th e diff erent temporal patterns between treatments showed that fl ooding increases the abundance of emerged seedlings and acts as a trigger for explosive recruitment shortly after water depletion.
As macrófitas aquáticas colonizam, em diferentes graus, a maioria dos ecossistemas lóticos e lênticos. Apesar da distribuição das macrófitas nas margens de lagos constituir um exemplo clássico de zonação, não existe acordo quanto aos fatores determinantes desse fenômeno. O presente trabalho teve por objetivo analisar a diferença na cobertura vegetal de três lagoas do Parque Estadual do Rio Doce; determinar se ocorre ou não sucessão de espécies na cobertura vegetal; e avaliar a distribuição das formas de vida e das espécies ao longo do gradiente de profundidade para cada lagoa. A composição da cobertura vegetal diferiu entre as lagoas estudadas. Contudo, apenas as lagoas Gambazinho e Preta apresentaram diferenças significativas entre si, enquanto a lagoa Dom Helvécio não diferiu das demais. Dessa forma, os resultados obtidos sugerem que cada lagoa constitui uma "ilha" em termos de diversidade, uma vez que muitas espécies ocorreram em apenas uma lagoa. A diversidade beta temporal apresentou uma substituição média de 70% das espécies e o principal fator que estruturou a comunidade de macrófitas nas lagoas estudadas foi o gradiente de profundidade.
Field collection and herbaria data did not allow to quantify the diversity of aquatic plants from Northern Brazil, so we could not detect biogeographic patterns. Therefore, our objectives were to identify and quantify the aquatic macrophytes of North Brazilian states, analyzing herbaria data plataforms (SpeciesLink and Flora do Brasil). The checklist was produced by bibliographic search (articles published between 1980 and 2000), herbaria collections of the platforms SpeciesLink and Flora do Brasil and field expeditions, where we utilized asystematic sampling. We also analyzed the floristic similarity of aquatic macrophytes among Northern Brazil, wetlands of distinct Brazilian regions and the Neotropics. We recorded 539 species, of which 48 are endemic to Brazil. The states with highest number of species were Amazonas and Pará, independently on platform. The most represented families were Poaceae (89 species), Podostemaceae (55), Cyperaceae (50) and Fabaceae (47). We highlight the unprecedent richness of Podostemaceae, due to our own field collection efforts on favorable habitats, 25 species being endemic. Emergent and/or amphibious plants (515) were dominant in total species richness and were best represented in lotic habitats. We found significant differences in richness and floristics among states, obtained from the platforms. There is floristic similarity among Northern states and other Brazilian wetlands. In conclusion, we observed a rich aquatic flora in Northern Brazil, in spite of scarcity of records for Acre, Rondonia and Tocantins; we highlight the unprecedent number of endemic species of Podostemaceae (25) and contrasting richness between SpeciesLink and Flora do Brasil. KEYWORDS: floristics, life forms, Podostemaceae, species richness Lista atualizada de macrófitas aquáticas da região Norte do Brasil RESUMOOs eforços de campo e os dados de herbários não nos permitiam quantificar a diversidade plantas aquáticas no Norte do Brasil e, com isso, nos impediam de traçar padrõres biogeográficos sobre essa comunidade. Assim, o presente estudo teve por objetivos identificar e quantificar as macrófitas aquáticas dos estados do Norte do Brasil, analisando duas plataformas de dados de herbarios (SpeciesLink e Flora do Brasil). O checklist baseou-se em levantamento bibliográfico (revistas e artigos publicados entre 1980 e 2000) e em coletas de campo, na qual foi utilizada amostragem de "caminhamento". Após a elaboração do checklist, verificaram-se os registros das espécies para os estados da região, consultando-se as coleções das plataformas SpeciesLink e Flora do Brasil. Foi analisada a similaridade de especies de macrófitas aquáticas do Neotrópico, Norte do Brasil e ecossistemas aquáticos de distintas regiões do país. Foram registradas 539 espécies, sendo 48 endêmicas do Brasil. As famílias mais representativas foram Poaceae (89 espécies), Podostemaceae (55), Cyperaceae (50) e Fabaceae (47). Ressaltamos a inédita riqueza de Podostemaceae, devida a nossos esforços de coleta em ambientes propícios, 25 esp...
Esta é uma breve revisão de alguns trabalhos recentes sobre diversidade de plantas aquáticas do Pantanal, da planície de inundação do Rio Paraná e de outras áreas úmidas de Mato Grosso do Sul, com algumas considerações florísticas. As áreas extra-planícies dos dois grandes rios são nascentes, veredas, campos úmidos, covais e varjões dos cerrados e da floresta estacionai, além de águas cristalinas de Bonito. A planície do Rio Paraná tem a menor área e 153 espécies, o Pantanal, com a maior área, tem 280 espécies, enquanto as demais pequenas áreas de cabeceiras e veredas têm mais do que o dobro da riqueza do Pantanal. São citadas algumas das espécies principais, exclusivas e invasoras atuais e potenciais como Hydrilla e a nova Urochloa humidicola cv. Tupi.
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