Interação ecológica entre duas espécies de macrófitas aquáticas flutuantes Pistia stratiotes L. e Salvinia molesta (Michell)

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Crescimento das macrófitas aquáticas flutuantes Eichhornia crassipes (Mart.) Solms, Pistia stratiotes L. e Salvinia molesta (Mitchell) em diferentes concentrações de nutrientes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito de diferentes concentrações de nutrientes na competição entre Salvinia molesta e Pistia stratiotes

Pistia stratiotes e Salvinia molesta são duas macrófitas aquáticas flutuantes predominantes em ambientes de água parada. Embora as duas espécies em questão ocorram em ambientes com altos níveis de fósforo, P. stratiotes tem seu crescimento limitado por baixas concentrações de nitrogênio e fósforo, enquanto S. molesta se desenvolve bem tanto em águas com baixas como com altas concentrações de nutrientes. Dessa forma, S. molesta tem maior habilidade competitiva do que P. stratiotes em baixas concentrações de nitrogênio e fósforo. Neste contexto, este trabalho teve por objetivo principal analisar a relação de competição entre P. stratiotes e S. molesta, quando submetidas a diferentes concentrações de nutrientes ao longo do tempo. O estudo foi desenvolvido em uma casa de vegetação do Jardim Experimental da Unesp de Rio Claro, com duração de 66 dias, no período entre 25 de janeiro e 31 de março de 2008. As duas espécies foram misturadas em proporções iguais de área, em seis unidades experimentais. Em intervalos entre 4 e 7 dias, os nutrientes de cada unidade foram trocados e medidos o pH e a temperatura da água, bem como a massa fresca, massa morta e o comprimento da raiz de cada espécie. Todas as concentrações de nutrientes oferecidas foram suficientes para o bom crescimento de P. stratiotes, a qual venceu a competição, limitando o crescimento de S. molesta por falta de espaço e luz, levando-a à exclusão competitiva. O crescimento de P.stratiotes aumentou à medida que maiores concentrações de nutrientes foram oferecidas. Além disso, a temperatura também parece ter influenciado o crescimento da espécie, sendo esse maior em maiores temperaturas. A parte submersa de ambas as espécies diminuiu ao longo do experimento, devido às maiores ofertas de nutrientes.

A new water weed, giant salvinia (Salvinia molesta), invades Lake Kyoga

Giant salvinia (Salvinia molesta) is an introduced invasive water weed in the tropics and subtropics It is a free floating weed that grows rapidly and forms extensive dense mats over still or slow moving waters.

Status of kariba weed (Salvinia molesta) infestation, its impacts and control options on Uganda’s water systems

Kariba weed (Salvinia molesta) is an invasive alien waterweed that was first recorded in Uganda in sheltered bays of Lake Kyoga in June 2013. This waterweed has become a common feature on Lake Kyoga and its associated rivers, streams and swamps, and has spread to other lakes notably Kwania and Albert in addition to Lake Kimira in Bugiri district.

Lo que nos molesta de otros y no confesamos: ¡me da pena decírtelo!

Fondo Margaritainés Restrepo

Assessing Biological Control Damage of Giant Salvinia with Field Reflectance Measurements and Aerial Photography

A study was conducted on a small pond in southeast Texas to evaluate the potential for using remote sensing technology to assess feeding damage on giant salvinia ( Salvinia molesta Mitchell) by the salvinia weevil ( Cyrtobagous salviniae Calder and Sands). Field spectral measurements showed that moderately damaged and severely damaged plants had lower visible and near-infrared reflectance values than healthy plants. Healthy, moderately damaged, and severely damaged giant salvinia plants could be differentiated in an aerial color-infrared photograph of the study site. Computer analysis of the photograph showed that the three damage level classes could be quantified. (PDF has 5 pages.)

Tilapia for Biological Control of Giant Salvinia

In August 1999, giant salvinia ( Salvinia molesta Mitchell) was found along the lower Colorado River in irrigation drainages. To investigate the slow spread and apparent control of giant salvinia in this region, the herbivorous fish, tilapia (Oreochromis niloticus Trewavas), was examined as a biological control agent. The study was conducted in a 5,000-L recirculating system. (PDF contains 4 pages.)

Remote sensing of giant salvinia in Texas waterways

Giant salvinia (Salvinia molesta Mitchell) is an invasive aquatic fern that has been discovered at several locations in southeast Texas. Field reflectance measurements were made on two classes of giant salvinia [green giant salvinia (green foliage) and senesced giant salvinia (mixture of green and brown foliage)] and several associated species. Reflectance measurements showed that green giant salvinia could be best distinguished at the visible green wavelength, whereas senesced giant salvinia could generally be best separated at the near-infrared (NIR) wavelength. Green giant salvinia and senesced giant salvinia could be detected on color-infrared (CIR) aerial photographs where them had pink and grayish-pink or olive-green image responses, respectively. Both classes of giant salvinia could be distinguished in reflectance measurements made on multiple dates and at several locations in southeast Texas. Likewise, they could he detected in CIR photographs obtained on several dates and at widely separated locations. Computer analysis of a CIR photographic transparency showed that green giant salvinia and senesced giant salvinia populations could he quantified. An accuracy assessment performed on the classified image showed an overall accuracy of 87.0%.

Effect of Cattail (Typha domingensis) Extracts, Leachates, and Selected Phenolic Compounds on Rates of Oxygen Production by Salvinia (Salvinia minima)

Salvinia (Salvinia minima Willd.) is a water fern found in Florida waters, usually associated with Lemna and other small free-floating species. Due to its buoyancy and mat-forming abilities, it is spread by moving waters. In 1994, salvinia was reported to be present in 247 water bodies in the state (out of 451 surveyed public waters, Schardt 1997). It is a small, rapidly growing species that can become a nuisance due to its explosive growth rates and its ability to shade underwater life (Oliver 1993). Any efforts toward management of salvinia populations must consider that, in reasonable amounts, its presence is desirable since it plays an important role in the overall ecosystem balance. New management alternatives need to be explored besides the conventional herbicide treatments; for example, it has been shown that the growth of S. molesta can be inhibited by extracts of the tropical weed parthenium (Parthenium hysterophorus) and its purified toxin parthenin (Pande 1994, 1996). We believe that cattail, Typha spp. may be a candidate for control of S. minima infestations. Cattail is an aggressive aquatic plant, and has the ability to expand over areas that weren't previously occupied by other species (Gallardo et al. 1998a and references cited there). In South Florida, T. domingensis is a natural component of the Everglades ecosystem, but in many cases it has become the dominant marsh species, outcompeting other native plants. In Florida public waters, this cattail species is the most dominant emergent species of aquatic plants (Schardt 1997). Several factors enable it to accomplish opportunistic expansion, including size, growth habits, adaptability to changes in the surroundings, and the release of compounds that can prevent the growth and development of other species. We have been concerned in the past with the inhibitory effects of the T. domingensis extracts, and the phenolic compounds mentioned before, towards the growth and propagation of S. minima (Gallardo et al. 1998b). This investigation deals with the impact of cattail materials on the rates of oxygen production of salvinia, as determined through a series of Warburg experiments (Martin et al. 1987, Prindle and Martin 1996).

Les gasteropodes aquatiques associés aux plantes flottantes

The gasteropods sampling from roots system of floating plants Pistia striatiotes, Salvinia molesta, Salvinia nymphellula, Eichhornia crassipes, show that those biotopes are not azoic. We collected 18 species of gasteropods. The mapping of the species collected has been realized and permitted to identify three regions and three groups of gasteropods: 1 The gasteropods collected between 5° and 7° South; 2 The gasteropods collected between 8° and 10° North; 3 The widespread gasteropods. The species distribution according to latitude shows that 90% of species are found between 5° and 6° South, 65% between 6° and 7° South, 20% between 7° and 8°, 20% between 8° and 9° and 15% between 9° and 10° North.

Les macrophytes aquatiques des berges lagunaires

This synthetic article describes the composition and organization of vegetations colonizing the Ebrié lagoon banks and provides original data on the recent evolution of this association consecutively to the accidental introduction of 2 new species of floating macrophytes (Salvinia molesta and Eichhornia crassipes).

¿Por qué lloran?

Las palabras, los juegos o las risas son formas de expresión bien toleradas por los adultos, pero existe un rechazo general con relación al llanto de los niños. Éste, es considerado como una forma de expresión molesta e innecesaria y se asume que hay que aprender a controlarlo e incluso, reprimirlo. En este artículo se presenta el llanto de los bebés como una expresión emocional necesaria para su equilibrio vital y se afirma que dicha expresión emocional puede tener efectos muy positivos en su salud física y emocional futura. Finalmente, se dan algunas pautas de actuación dirigidas a los padres y educadores para enfrentar el momento del llanto del bebé.

Morphological Notes on the Worker and Queen Larvae of the Thief Ant Solenopsis helena (Hymenoptera, Formicidae, Myrmicinae) from Brazil

Young and mature larvae of queen and workers of the thief ant, Solenopsis helena, are herein described for the first time. Specimens were treated and described by usual methods of light and scanning electron microscopy. Many of the observed characteristics confirmed traits of the thief ant larva, reinforcing the assumption that they are a distinct group from fire ants. The larva of S. helena can be recognized from other close species by details of the mouthparts, but seem extensively similar to Solenopsis molesta. These findings are useful for taxonomic studies and phylogenetic inferences.

Controle químico de plantas daninhas aquáticas em condições controladas - caixa d'água

Durante o ano de 1998 foram conduzidos quatro experimentos em Botucatu, Estado de São Paulo, Brasil, em condições de caixas d'água, com o objetivo de estudar o efeito de alguns herbicidas sobre Eicchornia crassipes, Pistia stratiotes, Thypha subulata e Salvinia molesta. Os herbicidas e doses utilizadas foram: imazapyr a 125, 250, 500, 1.000, 1.500 e 2.000 g e.a./ha; 2,4 D a 1.200 g e.a./ha; glyphosate a 3.360 g e.a./ha. Houve, ainda, uma testemunha sem aplicação de herbicidas. Os experimentos foram instalados no delineamento experimental em blocos ao acaso, com quatro repetições. As parcelas experimentais foram constituídas pelas caixas d'água com dimensões de 60x60x60 cm e colocadas a pleno sol no campo. Utilizou-se 3, 12, 25 e 60 plantas/caixa de T. subulata, P. stratiotes, E. crassipes e S. molesta, respectivamente. Os herbicidas foram aplicados com pulverizador costal a pressão constante de CO2 de 1,75 Bar, munido de barra com bicos Teejet 110.02 VS e com um consumo de calda de 200 l/ha. Foram efetuadas avaliações visuais de controle de sete em sete dias por 35 a 49 dias, dependendo da espécie. Todos os herbicidas testados foram eficientes no controle de E. crassipes e o imazapyr foi o único herbicida a promover morte total das plantas, independente da dose utilizada. Os herbicidas 2,4 D e glyphosate não foram eficientes no controle de P. stratiotes. O herbicida imazapyr foi eficiente no controle de P. stratiotes, exceto na dose de 125 g e.a./ha. Todos os herbicidas foram eficientes no controle de T. subulata, exceção ao imazapyr na dose de125 g e.a./ha. Houve rebrota de T. subulata nas parcelas aplicadas com 2,4 D. Nenhum tratamento químico foi eficiente no controle de S. molesta.