Submitted by IGOR CRUZ MALASPINA null (igormalaspina@yahoo.com.br) on 2016-05-02T03:49:51Z No. of bitstreams: 1 tese final corrigida.pdf: 1689161 bytes, checksum: c5816b602bb2cec611e1907c2cb51fce (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-05-04T14:02:07Z (GMT) No. of bitstreams: 1 malaspina_ic_dr_jabo.pdf: 1689161 bytes, checksum: c5816b602bb2cec611e1907c2cb51fce (MD5) / Made available in DSpace on 2016-05-04T14:02:07Z (GMT). No. of bitstreams: 1 malaspina_ic_dr_jabo.pdf: 1689161 bytes, checksum: c5816b602bb2cec611e1907c2cb51fce (MD5) Previous issue date: 2016-04-01 / As macrófitas aquáticas possuem papel fundamental nos ecossistemas aquáticos participando dos processos de ciclagem de nutrientes, além de servirem como abrigo e alimento para muitas espécies de peixes e outros organismos. Dentre os principais métodos de controle de macrófitas está o controle químico com o uso de herbicidas. O objetivo deste estudo foi realizar o controle químico da macrófita Hydrilla verticillata com a aplicação isolada de diquat e hidróxido de cobre, e da mistura de diquat + 1% de hidróxido de cobre. O primeiro experimento para o controle da H. verticillata e da microalga Ankistrodesmus gracilis foi realizado em sala de bioensaio em recipientes plásticos de 1,5 litros, sendo todos os tratamentos testados eficientes no controle da macrófita e da microalga. Posteriormente, foram realizados experimentos em condições de microcosmos de concreto de 600 litros e em mesocosmos de concreto de 1200 litros, com o monitoramento de variáveis da qualidade da água (temperatura, oxigênio dissolvido, condutividade elétrica e pH), teor de clorofila a, demanda biológica de oxigênio (DBO) e demanda química de oxigênio (DQO) por um período de sessenta dias após a aplicação dos tratamentos. A mistura de diquat + 1% de hidróxido de cobre foi o tratamento mais eficaz no controle da macrófita Hydrilla verticillata para a maioria dos parâmetros analisados, havendo alteração nas variáveis de qualidade da água. Foram também realizados experimentos ecotoxicológicos para organismos não-alvo (Hyphessobrycon eques, Pomacea canaliculata, Lemna minor e Azolla caroliniana) com diquat, oxicloreto e hidróxido de cobre, onde a mistura de diquat + 1% de oxicloreto de cobre foi a mais tóxica para os organismos bioindicadores e a macrófita Lemna minor foi o bioindicador que apresentou a maior sensibilidade aos agroquímicos testados. / The macrophytes have a fundamental role in aquatic ecosystems participating in nutrient cycling processes, as well as serving as shelter and food for many species of fish and other organisms. Among the main weeds control methods is chemical control using herbicides. The aim of this study was the chemical control of the macrophyte Hydrilla verticillata with isolated application of diquat and copper hydroxide, and the mixture of diquat + 1% copper hydroxide. The first experiment for the control of H. verticillata and microalgae Ankistrodesmus gracilis was held in bioassay room in plastic containers of 1.5 liters, with all treatments tested effective in controlling macrophyte and microalgae. Subsequently, experiments were carried out under conditions of 600 liters concrete microcosms and in 1200 liters concrete mesocosms, with the monitoring of water quality variables (temperature, dissolved oxygen, electrical conductivity and pH), content chlorophyll a, demand biological oxygen (BOD) and chemical oxygen demand (COD) for a period of sixty days after the application of treatments. The mixture diquat + 1% copper hydroxide was the most effective treatment in Hydrilla verticillata of weed control for the majority of parameters, with change in water quality variables. Ecotoxicological experiments were also carried out for non-target organisms (Hyphessobrycon eques, Pomacea canaliculata, Lemna minor and Azolla caroliniana) with diquat, oxychloride and copper hydroxide, wherein the mixture of diquat + 1% copper oxychloride is more toxic to bioindicators organisms and macrophyte Lemna minor was bioindicador with the highest sensitivity to the tested pesticides.

Research provides biological and ecological information on Hydrilla Verticillata (L. f.) Royle in Gatun Lake, Panama for an ongoing management program of aquatic weeds in the Panama Canal. Morphological and genetic variation, standing crop and life cycle were determined.

Two experiments were conducted to investigate the hypothesis that exotic macrophytes alter littoral zone habitat and impact fish that inhabit these areas. The pond experiment was conducted to explore impacts of exotic invasive plants on growth and condition of juvenile largemouth bass (Micropterus salmoides). The second experiment was conducted at a smaller scale in aquaria to simulate an invasion of hydrilla (Hydrilla verticillata) and its influence on juvenile bass foraging. Fish experienced slower growth in the hydrilla treatment than in the diverse, and the ability of bass to capture prey fish was impeded in hydrilla. Juvenile bass growth decreased in habitats containing hydrilla and is likely a result of increased difficulty in capturing quality prey items such as small fish. Results from the two experiments collectively supported my hypothesis that hydrilla growth altered the littoral zone habitat such that foraging was hindered and resulted in slower growth.

No description available.

Exotic invasive plant species can alter aquatic habitats potentially influencing the macroinvertebrate community and foraging fishes. Therefore, I investigated the hypothesis that Hydrilla verticillata will alter habitat important to macroinvertebrate community structure and bluegill foraging efficiency. Studies were conducted in ponds and aquaria. At the pond level, macroinvertebrate abundance, richness, and biomass in a hydrilla-dominated habitat did not differ significantly from a diverse plant habitat. Indicator taxa did differ significantly between respective treatments. The data suggest hydrilla beds may not provide increased macroinvertebrate abundance and richness compared to diverse plant beds as previously thought. In aquaria, habitat complexity (Ihv) and light transmittance were influenced by increasing the homogeneity of hydrilla in an aquatic bed habitat. In addition, bluegill foraging efficiency was affected negatively by increasing spatial complexity of a hydrilla dominated habitat. Therefore, a shift to a monotypic hydrilla habitat can alter macroinvertebrate community composition and impact bluegill foraging success.

A study of Asian clam (Corbicula fluminea Müller) colonization in relation to changes in aquatic vegetation community as a result of management of Hydrilla verticillata (L. f.) Royle with grass carp was conducted at the Lewisville Aquatic Ecosystem Research Facility (LAERF), Lewisville, TX, from April 2015 through October 2016. Percent vegetation cover, C. fluminea abundance and water quality metrics (pH, turbidity, conductivity, DO, calcium, chlorophyll a) from 16 experimental subjects were analyzed. Treatments included four replicated grass carp stocking densities; 1-control with no fish stocked (n = 4), 2-low density of 40-43 fish per vegetated ha (n = 4), 3-medium density of 72-81 fish per vegetated ha (n = 4) and 4-high density of 110-129 fish per vegetated ha (n = 4). Data analysis showed statistical significance in the relation of C. fluminea abundance to percent vegetation cover (multiple linear regression, r2 = 0.820), grass carp stocking densities (two-way analysis of variance, p = <0.001) and chlorophyll a (multiple linear regression, r2 = 0.339). Findings of this research indicate the possibility that management of hydrilla had enabled establishment of secondary invasive species.