Loss of weight and concentration of carbon, nitrogen, and phosphorus during decomposition of Eichhornia azurea in the floodplain of the upper Paraná river, Brazil

Pagioro, Thomaz Aurélio; Thomaz, Sidinei Magela

doi:10.1590/s0034-71081998000400007

Cited by 14 publications

(14 citation statements)

References 8 publications

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“…The breakdown coefficient of E. azurea leaves found in the present study (k = 0.018 d x1 ) was higher than the values reported for this species in other studies of Brazilian lentic systems: Roland et al (1990) in the Inferna˜o Lagoon (k = 0.011 d x1 ); Pagioro and Thomaz (1998) in the Garc¸as Lagoon (k = 0.0048 d x1 ); Stripari and Henry (2002) in a marginal lake of the Paranapanema River (dry season: k = 0.014 d x1 ; rainy season: k = 0.018 d x1 ). Differences in leaf decomposition rates of the same species can be attributed to different environmental conditions (Schulze and Walker, 1997), such as water temperature, electrical conductivity and dissolved oxygen.…”

Section: Discussion Leaf Breakdowncontrasting

confidence: 77%

Colonization by oligochaetes (Annelida: Clitellata) in decomposing leaves ofEichhornia azurea(SW.) Kunth (Pontederiaceae) in a neotropical lentic system

Martins

Silveira

Alves

2011

Ann. Limnol. - Int. J. Lim.

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-The objective of the present study was to examine the colonization of oligochaetes during the decomposition of leaves of the macrophyte Eichhornia azurea in a lentic system in southeastern Brazil. The experiment was conducted between September and November 2007, with the use of 21 nylon bags measuring 15 r 15 cm with 2 mm mesh, each containing 10 g of dried leaves. The bags were removed from the lake after 2, 5, 8, 12, 25, 45 and 65 days. At the end of the experiment, 31.40% of the initial mass remained, and the decomposition rate was 0.018 d x1 . The mean density of oligochaetes during the experiment was 32.81 ¡ 9.58 ind.g x1 DM. The sub-families Naidinae and Pristininae accounted for 99.83% of the oligochaetes. The substrate quality influenced the colonization of E. azurea leaves, as observed from the cluster analysis by the formation of two groups based on increased density during the experiment, indicating a degradative ecological succession. During the decomposition there were changes in the community of oligochaetes, resulting from differences in the ability to exploit various food sources, with predominance of predators in the first decomposition phase and of collectors at the end of the experiment.

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Section: Discussion Leaf Breakdowncontrasting

confidence: 77%

Colonization by oligochaetes (Annelida: Clitellata) in decomposing leaves ofEichhornia azurea(SW.) Kunth (Pontederiaceae) in a neotropical lentic system

Martins

Silveira

Alves

2011

Ann. Limnol. - Int. J. Lim.

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“…But, an initial decrease was recorded in the first 14 days and it was due to detritus lixiviation. However, Roland et al (1990) and Pagioro & Thomaz (1998), both studying the Eichhornia azurea decomposition, observed a reduction on nitrogen concentrations at the end of the experiments.…”

Section: Discussionmentioning

confidence: 91%

“…In this phase, physical processes as cellular lysis and lixiviation occurred and a great quantity of organic and inorganic nutrients is removed from plants into the aqueous solutions. Pagioro & Thomaz (1998), in a laboratory study on Eichhornia azurea decomposition sampled in two different ecosystems (Paraná River and Garças Lake) from the High Paraná River floodplain, found a loss of approximately 15% of leaf biomass during the first 24 hours, a slower decomposition therefore. In Camargo Lake, the second phase showed a very low velocity in decomposition, corresponding to 34% and 49% of initial biomass for 71 days in the dry and rainy periods, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…The polyphenol reduction causes an increase in the palability of the remaining organic matter for the members of the detritivorous chain. Pagioro & Thomaz (1998), in laboratory studies, showed that the decomposition rates of Eichhornia azurea from Paraná River and Garças Lake (a lateral lake) are very similar and low. However, in another investigation, Pagioro & Thomaz (1999) found that the decomposition rates of Eichhornia azurea, from Cortado channel and Guaraná Lake, in the floodplain of High Paraná River, were very different, despite the fact that the changes in ash and phosphorus contents were similar in both environments.…”

Section: Introductionmentioning

confidence: 99%

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The invertebrate colonization during decomposition of Eichhornia azurea kunth in a lateral lake in the mouth zone of Paranapanema River into Jurumirim Reservoir (São Paulo, Brazil)

Stripari

Henry

2002

Braz. J. Biol.

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The invertebrate colonization during decomposition of Eichhornia azurea was observed in a lateral lake in the mouth zone of Paranapanema River into Jurumirim Reservoir in two periods of the year. The litter bags method was used for measuring the decomposition rate as well as to evaluate the invertebrates colonization. Forty-two litter bags, measuring 15 × 20 cm in size and 2 mm mesh net, were incubated "in situ". Six litter bags (three for colonization and three for decomposition measurements) were removed after the 1 st , 3 rd , 7 th , 14 th , 28 th , 56 th and 72 nd days of incubation. After each day, the material was carefully cleaned for detritus removal and invertebrate sampling. The biological material was fixed with 4% formaline and then sorted and identified. The remaining plant material was dried in an oven (at 60 o C) and weighed. A fast material loss occurred during the first 24 hours and the decomposition rate was higher during the rainy season than in the dry season. A peak on invertebrate density (110 ind.g.DW -1 ) on the remaining detritus of Eichhornia azurea was recorded in the 56 th day of dry season, when the polyphenol concentration of plant detritus was 0.57 UDO.g.DW -1 . In the rainy season, higher density was found in the 28 th day of incubation, when the polyphenol concentration was 4.36 UDO.g.DW -1 . Apparently, the reduction in the polyphenol concentration was followed by an increase in invertebrate densities. The majority of the species observed in the detritus belongs to the collector group that was dominant after the 7 th and 14 th days in the rainy and dry seasons, respectively.Key words: decomposition, colonization, invertebrate, Eichhornia azurea, lake. RESUMO Decomposição de Eichhornia azurea e colonização por invertebradosA colonização por invertebrados durante o processo de decomposição de Eichhornia azurea foi examinada em duas épocas do ano na zona de desembocadura do Rio Paranapanema,

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“…The half-life of a congener, U. subquadripara (Trin.) Hitch., registered in oligotrophic tropical environments, is around 6.3 years (Rocha, 2012), while the half-life of a largely distributed native macrophyte, like Eichhornia azurea (Sw.) Kunth, was estimated in only 0.4 years (Pagioro and Thomaz, 1998). Considering the dominated ones, where an asymptote indicates that the full richness has been recorded.…”

Section: Resultsmentioning

confidence: 98%

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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Loss of weight and concentration of carbon, nitrogen, and phosphorus during decomposition of Eichhornia azurea in the floodplain of the upper Paraná river, Brazil

Cited by 14 publications

References 8 publications

Colonization by oligochaetes (Annelida: Clitellata) in decomposing leaves ofEichhornia azurea(SW.) Kunth (Pontederiaceae) in a neotropical lentic system

Colonization by oligochaetes (Annelida: Clitellata) in decomposing leaves ofEichhornia azurea(SW.) Kunth (Pontederiaceae) in a neotropical lentic system

The invertebrate colonization during decomposition of Eichhornia azurea kunth in a lateral lake in the mouth zone of Paranapanema River into Jurumirim Reservoir (São Paulo, Brazil)

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

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