Estudo da degradação da biomassa de três espécies de plantas aquáticas no reservatório da UHE de Americana-SP

Negrisoli, E.; Corrêa, Marcelo Rocha; Velini, Edivaldo Domingues; Bravin, L.F.N.; Marchi, Sidnei Roberto de; Cavenaghi, A.L.; Rossi, Caio Vitagliano Santi

doi:10.1590/s0100-83582006000200003

Cited by 3 publications

(3 citation statements)

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“…When it becomes dominant, invasive Poaceae (like U. arrecta) makes stands practically mono-specific, lowering biotic heterogeneity and changing habitat complexity (Negrisoli et al, 2006). In a recent investigation in streams on the coast of the State of São Paulo, Amorim (2012) showed that native macrophyte richness in patches dominated by U. subquadripara were much lower than in patches dominated by a native species (Eichhornia azurea Kunth), indicating impacts of the invasive species.…”

Section: Resultsmentioning

confidence: 99%

Diversity and biomass of native macrophytes are negatively related to dominance of an invasive Poaceae in Brazilian sub-tropical streams

2013

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Diversity and biomass of native macrophytes are negatively related to dominance of an invasive Poaceae in Brazilian sub-tropical streamsA diversidade e a biomassa de macrófitas nativas são negativamente relacionadas com a dominância de uma Poaceae invasora em riachos sub-tropicais Abstract: Besides exacerbated exploitation, pollution, flow alteration and habitats degradation, freshwater biodiversity is also threatened by biological invasions. This paper addresses how native aquatic macrophyte communities are affected by the non-native species Urochloa arrecta, a current successful invader in Brazilian freshwater systems. We compared the native macrophytes colonizing patches dominated and non-dominated by this invader species. We surveyed eight streams in Northwest Paraná State (Brazil). In each stream, we recorded native macrophytes' richness and biomass in sites where U. arrecta was dominant and in sites where it was not dominant or absent. No native species were found in seven, out of the eight investigated sites where U. arrecta was dominant. Thus, we found higher native species richness, Shannon index and native biomass values in sites without dominance of U. arrecta than in sites dominated by this invader. Although difficult to conclude about causes of such differences, we infer that the elevated biomass production by this grass might be the primary reason for alterations in invaded environments and for the consequent impacts on macrophytes' native communities. However, biotic resistance offered by native richer sites could be an alternative explanation for our results. To mitigate potential impacts and to prevent future environmental perturbations, we propose mechanical removal of the invasive species and maintenance or restoration of riparian vegetation, for freshwater ecosystems have vital importance for the maintenance of ecological services and biodiversity and should be preserved.Keywords: signal grass, nvasive macrophytes, freshwater, biodiversity.Resumo: Juntamente com a exploração exacerbada, poluição, alteração de regime hidrológico e degradação de habitas as invasões biológicas são consideradas uma ameaça à biodiversidade dos ecossistemas aquáticos continentais. Nesse sentido, a Poaceae Urochloa arrecta é reconhecida como uma invasora bem sucedida em ambientes aquáticos brasileiros. Nós comparamos bancos de macrófitas dominados e não-dominados por esta invasora. Foram amostrados oito córregos no noroeste do Estado do Paraná (Brasil). Em cada córrego registramos a riqueza e a biomassa de macrófitas nativas em locais onde U. arrecta era dominante e em locais onde ela não dominava ou era ausente. Em sete dos oito locais onde U. arrecta dominava, não haviam macrófitas nativas. Assim, encontramos maiores riqueza de espécies nativas, índice de Shannon e biomassa nativa nos locais não dominados por U. arrecta com relação aos locais dominados. Apesar da dificuldade em se extrair conclusões sobre as causas dessas diferenças, inferimos que a elevada biomassa da invasora pode ser a principal fonte de altera...

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Section: Resultsmentioning

confidence: 99%

Diversity and biomass of native macrophytes are negatively related to dominance of an invasive Poaceae in Brazilian sub-tropical streams

2013

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“…The loss of heterogeneity, which was also shown in other investigations (Negrisoli et al . , Aday ), is enhanced by the absence of native macrophytes in the more extensively developed patches of U. arrecta (see Fig. A), which become monospecific.…”

Section: Discussionmentioning

confidence: 97%

Effects of an Invasive Alien Poaceae on Aquatic Macrophytes and Fish Communities in a Neotropical Reservoir

et al. 2013

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We investigated the potential effects of an invasive alien Poaceae (Urochloa arrecta) on the abundance, richness, and composition of native macrophytes and fish. Samples were collected in patches of macrophytes dominated by the invasive species and in others dominated by a native macrophyte (Eichhornia azurea). We assessed the potential effects of these two species on macrophyte and fish abundance and richness, as well as in fish assemblage composition. The effects of both macrophytes did not differ when they were in similar, low biomasses. Consistent with our expectations, however, the abundance of native macrophytes and fish decreased with increasing U. arrecta biomass, and both assemblages were eliminated at the extreme high levels of biomass attained by this species. In contrast, E. azurea did not affect the assemblages because this native species never reached levels of biomass as high as those recorded for the invasive species. Competition for space and light most likely determines the elimination of macrophytes in patches that are extensively colonized by U. arrecta, whereas fish assemblages do not occupy these patches due most likely to the limited space available for movement and foraging. Thus, U. arrecta is a source of concern for biodiversity conservation because it has negative influences on both assemblages when it is well developed, which is true in the later stages of the invasion process.

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“…These include hampering navigation and water extraction, jeopardizing electrical energy production and leisure activities, obstructing water flow in irrigation canals and contributing to the reduction of dissolved oxygen in the water. [8][9][10][11] The use of macrophytes for whatever means depends on determining several physicochemical properties typical to the intended application and the accumulated pollution content, as well as compliance with legislation. The application of macrophytes for nutrient removal in temporary rivers that appear during the dry season and where pollution content is seasonal has not yet been fully studied.…”

Section: Introductionmentioning

confidence: 99%

Temporal and physiological influence of the absorption of nutrients and toxic elements by Eichhornia crassipes

et al. 2011

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Aquatic macrophytes are a very important subject of study due to their capacity to restore polluted aquatic environments as they need high nutrient concentrations to develop. The present study aims to determine their temporal and physiological influence on the amount of total nitrogen, gross protein, P, Cu, Ni, Co, Cd, Pb and Cr absorbed by Eichhornia crassipes (water hyacinth) in the River Apodi/Mossoró, RN, Brazil, identifying viable possibilities for the use of cultivated biomass. Results obtained from the parameters analyzed show that these substances are impacted by the temporality and physiology of Eichhornia crassipes. Leaves showed higher crude protein and macronutrients, while the content of micronutrients and toxic elements was higher in roots. It could, therefore, be utilized to improve water quality in the River Apodi/Mossoró.

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Estudo da degradação da biomassa de três espécies de plantas aquáticas no reservatório da UHE de Americana-SP

Cited by 3 publications

References 6 publications

Diversity and biomass of native macrophytes are negatively related to dominance of an invasive Poaceae in Brazilian sub-tropical streams

Diversity and biomass of native macrophytes are negatively related to dominance of an invasive Poaceae in Brazilian sub-tropical streams

Effects of an Invasive Alien Poaceae on Aquatic Macrophytes and Fish Communities in a Neotropical Reservoir

Temporal and physiological influence of the absorption of nutrients and toxic elements by Eichhornia crassipes

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