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Dive into the research topics where Thaisa S. Michelan is active.

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Featured researches published by Thaisa S. Michelan.


PLOS ONE | 2013

Native Macrophyte Density and Richness Affect the Invasiveness of a Tropical Poaceae Species

Thaisa S. Michelan; Sidinei Magela Thomaz; Luis Mauricio Bini

The role of the native species richness and density in ecosystem invasibility is a matter of concern for both ecologists and managers. We tested the hypothesis that the invasiveness of Urochloa arrecta (non-native in the Neotropics) is negatively affected by the species richness and abundance of native aquatic macrophytes in freshwater ecosystems. We first created four levels of macrophyte richness in a greenhouse (richness experiment), and we then manipulated the densities of the same native species in a second experiment (density experiment). When the native macrophytes were adults, fragments of U. arrecta were added, and their growth was assessed. Our results from the richness experiment corroborated the hypothesis of a negative relationship between the native species richness and the growth of U. arrecta, as measured by sprout length and root biomass. However, the resistance to invasion was not attributed to the presence of a particular native species with a greater competitive ability. In the density experiment, U. arrecta growth decreased significantly with an increased density of all five of the native species. Density strongly affected the performance of the Poaceae in a negative manner, suggesting that patches that are densely colonized by native macrophytes and less subject to disturbances will be more resistant to invasion than those that are poorly colonized and more commonly subjected to disturbances. Our density experiment also showed that some species exhibit a higher competitive ability than others (sampling effect). Although native richness and abundance clearly limit the colonization and establishment of U. arrecta, these factors cannot completely prevent the invasion of aquatic ecosystems by this Poaceae species.


Hydrobiologia | 2015

Propagule pressure, invasibility of freshwater ecosystems by macrophytes and their ecological impacts: a review of tropical freshwater ecosystems

Sidinei Magela Thomaz; Roger Paulo Mormul; Thaisa S. Michelan

In this review, we aim to draw parallels between the principal concepts of invasion biology, developed mainly for terrestrial plants in temperate regions, with findings for macrophytes recorded in tropical inland waters. In these ecosystems, the most important abiotic and biotic filters influencing invasion success are related to water and sediment conditions, light, disturbance, hydrology and the diversity and density of native species. The main impacts are related to direct and indirect changes in the populations and communities of native macrophytes and other associated organisms. Non-native ecosystem engineer species of macrophytes can affect ecosystems directly, and after affecting ecosystems, their effects can extend to populations and communities. High plant growth rates in the tropics could lead to rapid invasion and larger impacts compared to temperate ecosystems. Although we found many parallels between ecosystems regarding the general concepts of invasion, areas that should receive further investigation in the tropics include (i) the synergistic interaction of multiple invasive species, (ii) the effects of regime shift on invasion success and vice versa and (iii) how climate change will affect the dynamics of macrophyte invasion in tropical ecosystems.


Brazilian Journal of Botany | 2015

Macrophyte species richness and composition are correlated with canopy openness and water depth in tropical floodplain lakes

Fabielle M. Bando; Thaisa S. Michelan; Eduardo Ribeiro Cunha; Bruno R. S. Figueiredo; Sidinei Magela Thomaz

Aquatic macrophytes colonize a variety of environments, and they play important roles in ecosystem function and in community structure. One key challenge for aquatic ecologists is to investigate the environmental factors that drive the richness and distribution of these plants. In this study, we assessed the importance of selected morphometric variables and of the canopy openness of the riparian vegetation to explain macrophyte species richness and composition. We sampled macrophytes along gradients of depth, littoral slope, distance from the connection with the river, and canopy openness in floodplain lakes connected with the Upper Paraná River. We used quadrats to survey a total of 40 sites in 11 lakes. We recorded 31 macrophyte species and found that macrophyte richness was best and positively correlated with canopy openness. This correlation suggests that canopy openness plays an important role as an environmental filter, regulating the amount of light availability for macrophytes. Macrophyte species composition was best correlated with depth, indicating that zonation of macrophyte species also occurs in these shallow lakes. These findings emphasize the importance of morphometric variables and canopy openness for structuring macrophyte assemblages. In addition, our results suggest that canopy openness and depth may be considered in management strategies aiming to recover macrophyte diversity and the processes mediated by aquatic macrophytes in small and shallow floodplain lakes.


Acta Limnologica Brasiliensia | 2015

Sediment composition mediates the invasibility of aquatic ecosystems by a non-native Poaceae species

José Vitor Botter Fasoli; Thaisa S. Michelan; Sidinei Magela Thomaz

Aim: To test the invasibility of aquatic ecosystems by an exotic species, we used the invasive macrophyte Urochloa arrecta, which has invaded many Neotropical waterbodies and has reduced biodiversity in these habitats. The extensive growth of this macrophyte can be related to its affinity for mud-rich sediments, which occur primarily in secondary river channels and lentic habitats.MethodsTo test this hypothesis, we cultivated U. arrecta in trays with different percentages of mud and we measured the sprout length and biomass of the plants after 75 days.ResultsOur results showed a positive and significant relationship between sediment mud percentage and nitrogen, phosphorus and organic matter. Both plant length and biomass increased significantly and continuously with increasing mud content, indicating that the growth of this species is not limited even at the highest levels of mud, which is shown to be toxic for other species of macrophytes. Thus, it is probable that sand-rich sites, such as river shores, are less vulnerable to invasion by this species than relatively mud-rich sites, such as lakes.ConclusionsThis finding indicates that relatively mud-rich ecosystems should be prioritised in monitoring programs to prevent invasion by this species. In addition, the slow development of this species in sandy sediments opens a potential window for its management, at least on small spatial scales. However, despite the reduced growth of U. arrecta in sand-rich sediments, this grass is able to grow in several types of sediments, which explains its spread in a variety of habitats in Neotropical freshwater ecosystems.


Freshwater Biology | 2010

Effects of an exotic invasive macrophyte (tropical signalgrass) on native plant community composition, species richness and functional diversity

Thaisa S. Michelan; Sidinei Magela Thomaz; Roger Paulo Mormul; Priscilla Carvalho


Acta Oecologica-international Journal of Ecology | 2009

Temporal trends and effects of diversity on occurrence of exotic macrophytes in a large reservoir

Sidinei Magela Thomaz; Priscilla Carvalho; Roger Paulo Mormul; Fernando Alves Ferreira; Márcio José Silveira; Thaisa S. Michelan


PLOS ONE | 2013

Incorrect Citations Give Unfair Credit to Review Authors in Ecology Journals

Mariana Carolina Teixeira; Sidinei Magela Thomaz; Thaisa S. Michelan; Roger Paulo Mormul; Thamis Meurer; José Vitor B. Fasolli; Márcio José Silveira


Journal of Limnology | 2014

The invasive aquatic macrophyte Hydrilla verticillata facilitates the establishment of the invasive mussel Limnoperna fortunei in Neotropical reservoirs

Thaisa S. Michelan; Márcio José Silveira; Danielle Katharine Petsch; Gisele Daiane Pinha; Sidinei Magela Thomaz


Aquatic Ecology | 2015

Zooplankton diversity in a dammed river basin is maintained by preserved tributaries in a tropical floodplain

Louizi de Souza Magalhães Braghin; Bruno R. S. Figueiredo; Thamis Meurer; Thaisa S. Michelan; Nadson Ressyé Simões; Claudia Costa Bonecker


Journal of Applied Ecology | 2017

Shade provided by riparian plants and biotic resistance by macrophytes reduce the establishment of an invasive Poaceae

Heloísa Beatriz Antoniazi Evangelista; Thaisa S. Michelan; Luiz Carlos Gomes; Sidinei Magela Thomaz

Collaboration


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Sidinei Magela Thomaz

Universidade Estadual de Maringá

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Roger Paulo Mormul

Universidade Estadual de Maringá

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Márcio José Silveira

Universidade Estadual de Maringá

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Bruno R. S. Figueiredo

Universidade Estadual de Maringá

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Fabielle M. Bando

Universidade Estadual de Maringá

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Priscilla Carvalho

Universidade Estadual de Maringá

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Thamis Meurer

Universidade Estadual de Maringá

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Claudia Costa Bonecker

Universidade Estadual de Maringá

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Danielle Katharine Petsch

Universidade Estadual de Maringá

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Eduardo Ribeiro Cunha

Universidade Estadual de Maringá

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