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Made available in DSpace on 2021-06-25T10:18:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Aim: Evaluating how groups of organisms vary in dispersal capability and how environmental, spatial and temporal signals vary across multiple scales is critical to elucidating metacommunity theory. We examined whether the relative contributions of environmental, spatial and hydrological factors have different effects on organismal groups with different dispersal abilities at three spatial scales, and how this knowledge contributes to our understanding of metacommunity dynamics. Location: Four major Brazilian floodplains, with the largest distance among them of 2,300 Km. Taxon: 10 aquatic organismal groups, ranging from bacterioplankton to fish. Methods: We sampled lakes connected to the main river in the low- and high-water periods of each floodplain between 2011 and 2012. Different biological groups were analysed across three hierarchical spatial scales (fine, intermediate and subcontinental) within and between floodplain systems. We applied a series of partial redundancy analyses to estimate the relative contributions of environmental factors, spatial factors and hydrological period for each biological group. Results: At the fine spatial scale, predominantly environmental factors and hydrological period structure metacommunities, although less so for microorganisms than for micro-invertebrates and macro-organisms. The relative importance of environmental factors increased at the intermediate spatial scale. At the subcontinental scale, the relative importance of spatial factors increased for all biological groups, but environmental factors remained the primary regulators of microorganisms even at the largest scale. Main conclusions: This study design allowed us to make more robust inferences about the mechanisms responsible for regulating community structure of distinct biological groups at different spatial scales. Our results suggest that biological groups displaying distinct body size likely determine the spatial extent at which environmental, spatial and hydrological processes prevail as the primary regulators of community structure. These findings are important in guiding the conservation and management of floodplain biodiversity because these systems are naturally highly heterogeneous in space and time. Universidade Estadual de Maringá (UEM) DBI/PEA/NUPÉLIA Departamento de Ecologia Instituto de Ciências Biológicas Universidade Federal de Goiás (UFG) Freshwater Centre Finnish Environment Institute (SYKE) Department of Botany University of British Columbia INPA-Instituto Nacional de Pesquisas da Amazônia Centro Universitário Ingá - Uningá/Engenharia Elétrica Departamento de Oceanografia e Limnologia – DOL Universidade Federal do Rio Grande do Norte (UFRN) Universidade de Brasília (UnB) American Museum of Natural History Department of Natural Sciences University of South Carolina Beaufort Department of Biology University of Illinois Springfield Departamento de Ecologia e Conservação - Programa de Pós-Graduação em Ecologia de Ecótono Universidade Federal de Tocantins (UFT) Departamento de Ecologia Instituto de Biociências Universidade Estadual Paulista (Unesp) Universidade Federal de Mato Grosso do Sul (UFMS) Royal Belgian Institute of Natural Sciences (RBINS) OD Nature Department of Biology University of Ghent UniCesumar–PPGTL Instituto Cesumar de Ciência Tecnologia e Inovação (ICETI) Departamento de Ecologia Instituto de Biociências Universidade Estadual Paulista (Unesp)

We investigated whether isotopic niche partitioning could mediate the coexistence between native (Hoplias sp. B) and non‐native (Hoplias mbigua) trahira in a Neotropical floodplain. We hypothesised that during the dry season both species inhabit isolated sites (i.e. lakes) and thus rely on distinct food resources to sustain their coexistence. We found evidence of trophic segregation among native and non‐native freshwater fish in the Upper Parana River, Brazil. Even though both species rely on the same primary littoral carbon sources and present similar trophic diversity, trophic segregation was attained through larger niche amplitude and smaller isotopic niche width for the non‐native fish. Three decades after initial invasion, non‐native Hoplias have distinct foraging behaviour and do not compete for trophic resources with native trahira; this is likely due to morpho‐anatomical differences. Limited morphological similarity between these congeneric species might be the strongest factor contributing to their coexistence in the Parana River floodplain during the dry season.

A systematic review was conducted to identify trends and gaps in studies concerning nonnative populations in a neotropical floodplain and identify which population ecology topics has been predominant among studies in such floodplains. The large majority of the articles were field observational studies based on nonnative fish populations. A focus on ecological interactions, in particular competition and predation, was predominant in these studies. Hypotheses related to environmental filters and biotic resistance were used most frequently to support studies on river the floodplain, but many studies not addressed the invasion theory. Impoundment was the introduction vector associated with the largest number of studies of nonnative populations. We present conceptual aspects that may guide future studies on nonnative population ecology and inform conservation policies in floodplain ecosystems.

Sugarcane is one of the main crops used around the world as a feedstock for the production of sucrose and biofuel. Prior to harvesting, sugarcane dry leaves are burned to facilitate manual cutting and enhance productivity. This practice generates ashes from sugarcane straw (hereafter referred as SCA), which may be carried to aquatic ecosystems, where its impacts on organisms and ecosystem integrity remain unknown. Here, we experimentally tested the toxicity of five different concentrations of SCA (0, 1000, 1500, 2000 and 2500 mg/L) on three native (Astyanax lacustris, Moenkhausia bonita and M. forestii) and two non-native (Oreochromis niloticus and Poecilia reticulata) fish from the Parana River Basin, Brazil. The toxicity was estimated by calculating the median lethal concentration (LC50-24h) and the hepatosomatic index (HSI). We hypothesised that native fish are more sensitive to an increase in SCA than non-native fish. We verified that the mortality of native fish sharply increased with the increase in higher SCA concentration (LC50-24h values: A. lacustris = 2525.71 mg/L, M. bonita = 2124.95 mg/L and M. forestii = 1981.74 mg/L). However, no deaths were recorded for non-native fish species in any SCA concentrations. Accordingly, the HSI index values statistically differed with the increase in SCA concentrations for native fish, while for non-native fish we did not observe any difference. Therefore, only native species died or suffered liver damage with an increase in SCA concentrations. Extrapolating our findings to natural environments, we suggest that sugarcane burning, a widely used agricultural technique, has the potential to reduce the population size of native organisms and facilitate the dominance of non-native fish species in aquatic ecosystems.

The processes that determine the coexistence of phylogenetically close species are very complex, particularly when species introduction leads to sympatry among species that did not co-evolved. We evaluated possible differences in δ13C and δ15N signatures between two piranha species (Serrasalmus marginatus and S. maculatus), in a system where S. marginatus invaded 30 years ago (floodplain ponds in the Upper Parana River). We predicted that carbon and nitrogen stable isotope values would not differ between piranha species. Additionally, we evaluated the abundance (CPUE) of both piranha populations along the years (1986–2015). Native and non-native Serrasalmus species have different δ13C signatures, likely exploiting different energy pathways on the food web. Overall, native and non-native piranhas have similar δ15N values and occupy the third trophic level in the food web. Regarding the two piranha population fluctuations, there was an inversion of dominance after the non-native species establishment, where S. marginatus became dominant over S. maculatus (after 1988). Our results showed that trophic niche dimension (revealed by trophic segregation) is not the reason of the observed inversion in the dominant species, and this could be a primary factor driving the persistence of the native species in the ecosystem.

The Devonian Escarpment (DEEPA), located in the south of Brazil, represents an important area of environmental preservation composed by grasslands, gallery forests, as well as rock outcrops and archaeological sites. A law project (LP 527/2016), which suggests a reduction of the DEEPA area in approximately 70% of its original area (from 393,579 to 125,895 ha), is currently being processed in the Paraná State House of Representatives. Such reduction seems to be related to economic interests (mainly agriculture and mining) in the state of Paraná. If approved, LP 527/2016 will allow farmers to deliberately expand their activities, with the suppression of natural forest as main consequence. Additionally, loss of faunal diversity, contamination of water and soils, and alteration in nutrient cycles are expected, due the intensive use of agrochemicals. In addition to the direct environmental consequences, we expect the disappearance of areas of high geological interest, reducing local geodiversity, as well as substantial economic losses with ecotourism. Brazil is a signatory to the United Nations Convention on Biological Diversity, where it undertakes to develop strategies to prevent biodiversity loss and ecosystem degradation by 2020. An approval of the LP would be contradictory, considering that there are few natural vegetation areas in this region of the country. We emphasize that the proposal of such projects goes against the sustainability in the country and disregard the scientific knowledge generated until then. Thus, it is necessary to develop regional and federal political objectives that guarantee economic development in a balanced way, considering the local bio and geodiversity, not the proposal of mechanisms that destroy them. Resumo: A Escarpa Devoniana (APAED), localizada no sul do Brasil, representa uma importante área de preservação ambiental composta por campos, matas de galeria, além de afloramentos rochosos e sítios arqueológicos. Atualmente, tramita na câmara dos deputados do estado do Paraná um projeto de lei estadual (PL 527/2016) que sugere a redução da área da APAED em aproximadamente 70% de sua área original (de 393.579 para 125.895 ha). Tal redução parece estar relacionada com interesses econômicos (principalmente agropecuária e mineração) no estado do Paraná. Caso aprovado, o PL 527/2016 permitirá que agricultores expandam suas atividades deliberadamente, tendo como consequência principal a supressão de áreas de floresta nativa. Com isso, espera-se perda de diversidade faunística, contaminação de água e solos e alteração nos ciclos de nutrientes, dado o aumento no uso de agroquímicos. Além das consequências ambientas diretas, podemos esperar o desaparecimento de elevado interesse geológico, reduzindo a geodiversidade local, além de substanciais perdas econômicas com ecoturismo. O Brasil é um dos países signatários da Convenção da Diversidade Biológica das Nações Unidas, onde se compromete a desenvolver estratégias que evitem a perda da biodiversidade e a degradação de ecossistemas até 2020. Assim, a aprovação desse projeto de lei é, no mínimo, contraditória considerando que existem poucas áreas de vegetação natural nessa região do país. Destacamos que a proposta de tais projetos vai contra a sustentabilidade no país e desconsideram o conhecimento científico gerado até então. Dessa forma, é necessário o desenvolvimento de objetivos políticos regionais e federais que garantam o desenvolvimento econômico de forma equilibrada, considerando a bio e geodiversidade local, e não a proposta de mecanismos que as destruam.

In this study, diet-tissue discrimination factors and turnover rates were determined from the somatic tissues of a detritivorous fish Prochilodus lineatus. The carbon (Δ(13) C) and nitrogen (Δ(15) N) diet-tissue discrimination factors varied for all feed rations with a range of Δ(13) C values between -1·9 and 3·6‰ and Δ(15) N between 3·3 and 5·7‰. Carbon turnover rate in the blood was 23·1 days for the C3 ration and 34·7 days for the C4 ration, in the liver was 9·9 days under the C3 ration and nitrogen turnover rate was the same (23·1 days) in the liver for both C4 and C3 -C4 rations, and 13·9 days in the muscle for C3 -C4 ration.

Bottom-feeding fish show great variation in trophic morphology, resulting in a wide array of feeding habits exploiting from periphyton in littoral habitats to ingesting larger amounts of litterfall from terrestrial habitats. Nevertheless, it has been proposed that, in temperate aquatic systems, the energetic demands from bottom-feeding fish are supplied by primary production from phytoplankton in pelagic habitats. Thus, we aimed to determine which of several energy sources support bottom-feeding fish in tropical aquatic systems, where primary producers are diverse. We performed samplings in the Parana River floodplain from primary producers in littoral (periphyton), pelagic (phytoplankton) and terrestrial habitats (riparian vegetation). Using simultaneous signatures of C and N isotope ratios, we analysed the possible origin of available energy in muscles of nine different bottom-feeding fish species. We verified that seven of the nine fish species had the highest contribution of carbon from a littoral source compared to other energy sources, independent of trophic category. The importance of periphyton may be related to the high abundance of substrates (such as macrophytes) that are available in the littoral zone of tropical aquatic systems. Finally, we suggest that the actual carbon dynamics among bottom-feeding fish and primary producers is species-specific, varying within the same trophic guild, and therefore, it is possible to refute the assumption that each trophic guild is specialised for a distinct carbon source.

Studies in freshwater ecosystems are seeking to improve understanding of carbon flow in food webs and stable isotopes have been influential in this work. However, variation in isotopic values of basal production sources could either be an asset or a hindrance depending on study objectives. We assessed the potential for basin geology and local limnological conditions to predict stable carbon and nitrogen isotope values of six carbon sources at multiple locations in four Neotropical floodplain ecosystems (Parana, Pantanal, Araguaia, and Amazon). Limnological conditions exhibited greater variation within than among systems. δ15N differed among basins for most carbon sources, but δ13C did not (though high within-basin variability for periphyton, phytoplankton and particulate organic carbon was observed). Although δ13C and δ15N values exhibited significant correlations with some limnological factors within and among basins, those relationships differed among carbon sources. Regression trees for both carbon and nitrogen isotopes for all sources depicted complex and in some cases nested relationships, and only very limited similarity was observed among trees for different carbon sources. Although limnological conditions predicted variation in isotope values of carbon sources, we suggest the resulting models were too complex to enable mathematical corrections of source isotope values among sites based on these parameters. The importance of local conditions in determining variation in source isotope values suggest that isotopes may be useful for examining habitat use, dispersal and patch dynamics within heterogeneous floodplain ecosystems, but spatial variability in isotope values needs to be explicitly considered when testing ecosystem models of carbon flow in these systems.

In order to identify the ontogenetic changes in the food items assimilated by the larvae of Plagioscion squamosissimus and Hypophthalmus edentatus, we analyzed the stomach content and the nitrogen isotopic value (δ 15N) from the larvae. Samplings were performed monthly, from October 2002 to March 2003, and October 2003 to March 2004 in the subbasin of the Ivinheima River (Upper Parana River floodplain), Mato Grosso do Sul State, Brazil. The food items assimilated by the larvae of P. squamosissimus changed with respect to the developmental stages. In the preflexion stage, we found a large contribution of phytoplankton, followed by zooplankton. During the flexion and post-flexion stages, we recorded a decrease in phytoplankton contribution, an increase in zooplankton contribution, and the presence of zoobenthos. In H. edentatus, phytoplankton made the greatest contribution, followed by zooplankton. Ontogenetic changes in δ 15N for this species were not detected. For both species, the food item predominantly...

The upper Paraná River floodplain is composed of several marginal lagoons, making it a natural breeding ground for many fish species at developmental stages. The aim of this study is to estimate the trophic positions of these fishes based on feed intake (measured via diet) and nitrogen assimilation (measured via δ15N). The monthly samplings were concentrated during the spawning season in the Ivinheima River, which is located in the upper Paraná River floodplain. The specimens were grouped into preflexion, flexion and postflexion stages. Trophic positions were estimated based on the isotope value of nitrogen and on diet. During the developmental stages of P. squamosissimus, there were significant differences in the isotope values of δ15N; for H. edentatus, however, no significant differences were found. During the developmental stages, both species were classified as either at or above the third trophic level. Once this information is obtained for other species and components of the ecosystem, it will not only provide a more precise view of the energy allocation and flow in the ecosystem, but will also make possible for management measures to promote sustainability in this environment. A planície de inundação do alto rio Paraná é formada por várias lagoas marginais, tornando-se um criadouro natural de várias espécies de peixes nos estágios de desenvolvimento. O objetivo do estudo foi estimar as posições tróficas destes peixes, com base no alimento consumido (medido através dieta) e o nitrogênio assimilado (medido através δ15N). As amostragens mensais concentraram-se no período de desova das espécies, no rio Ivinheima, na planície de inundação do alto rio Paraná. Os espécimes foram agrupados em: pré-flexão, flexão e pós-flexão. As posições tróficas foram estimadas com base no valor isotópico de nitrogênio e na dieta. Nas fases de desenvolvimento de P. squamosissimus houve diferença significativa nos valores isotópicos de δ15N, enquanto que, para H. edentatus, não foram identificadas. Ambas as espécies, durante os estágios de desenvolvimento, foram classificadas em igual ou acima do terceiro nível trófico. Estas informações, quando obtidas para outras espécies de peixes e componentes do ecossistema, fornecerão uma visão mais precisa da distribuição e fluxo de energia no ecossistema, além de tornar possível medidas de manejo, que visem promover a sustentabilidade deste ambiente.

The upper Paraná River floodplain is composed of several marginal lagoons, making it a natural breeding ground for many fish species at developmental stages. The aim of this study is to estimate the trophic positions of these fishes based on feed intake (measured via diet) and nitrogen assimilation (measured via δ15N). The monthly samplings were concentrated during the spawning season in the Ivinheima River, which is located in the upper Paraná River floodplain. The specimens were grouped into preflexion, flexion and postflexion stages. Trophic positions were estimated based on the isotope value of nitrogen and on diet. During the developmental stages of P. squamosissimus, there were significant differences in the isotope values of δ15N; for H. edentatus, however, no significant differences were found. During the developmental stages, both species were classified as either at or above the third trophic level. Once this information is obtained for other species and components of the ecosystem, it will not only provide a more precise view of the energy allocation and flow in the ecosystem, but will also make possible for management measures to promote sustainability in this environment.A planície de inundação do alto rio Paraná é formada por várias lagoas marginais, tornando-se um criadouro natural de várias espécies de peixes nos estágios de desenvolvimento. O objetivo do estudo foi estimar as posições tróficas destes peixes, com base no alimento consumido (medido através dieta) e o nitrogênio assimilado (medido através δ15N). As amostragens mensais concentraram-se no período de desova das espécies, no rio Ivinheima, na planície de inundação do alto rio Paraná. Os espécimes foram agrupados em: pré-flexão, flexão e pós-flexão. As posições tróficas foram estimadas com base no valor isotópico de nitrogênio e na dieta. Nas fases de desenvolvimento de P. squamosissimus houve diferença significativa nos valores isotópicos de δ15N, enquanto que, para H. edentatus, não foram identificadas. Ambas as espécies, durante os estágios de desenvolvimento, foram classificadas em igual ou acima do terceiro nível trófico. Estas informações, quando obtidas para outras espécies de peixes e componentes do ecossistema, fornecerão uma visão mais precisa da distribuição e fluxo de energia no ecossistema, além de tornar possível medidas de manejo, que visem promover a sustentabilidade deste ambiente.

The aim of this work was to determine the caloric density of leaves, stems and roots of aquatic macrophytes in different environments of the Baía subsystem (Baía river and Fechada and Guaraná lagoons) on the Upper Paraná river floodplain, in addition to identify the variability between ecological groups. Samplings of Eichhornia crassipes, Salvinia spp, Pistia stratiotes, Eichhornia azurea, Polygonum sp, Cyperaceae and Poaceae were carried out in February 2003. Spatial differences in the caloric densities were not observed for these plants. Caloric density values varied from 1906.9 cal/g dry weight (root) to 4675.0 cal/g dry weight (leaf). However, significant differences between the caloric content averages of the vegetative structures were observed only for Polygonum sp and Salvinia spp. In relation to the ecological groups, the highest average value was verified for the emergent macrophytes (3529.7 ± 722.5), which were significantly different from the floating ones (3056.5 ± 571.0). There was no difference between the sites included in the subsystem when the caloric densities were compared.O presente trabalho teve por objetivo determinar a densidade calórica de folhas, caules e raízes de macrófitas aquáticas, em diferentes ambientes do subsistema Baía (Rio Baía e lagoas Fechada e do Guaraná) na planície de inundação do alto rio Paraná, além de identificar a variabilidade entre grupos ecológicos. As amostragens foram realizadas em fevereiro de 2003, sendo coletadas amostras de diferentes macrófitas, Eichhornia crassipes, Salvinia spp, Pistia stratiotes, Eichhornia azurea, Polygonum sp, Cyperaceae e Poaceae. Diferenças espaciais nas densidades calóricas não foram observadas para as plantas estudadas. Os valores de densidade calórica variaram de 1906,9 cal/g de peso seco (raiz) a 4675,0 cal/g de peso seco (folha). Entretanto, diferenças significativas entre as médias dos conteúdos calóricos das estruturas vegetativas foram observadas somente para Polygonum sp e Salvinia spp. Em relação aos grupos ecológicos, o maior valor médio foi verificado para as macrófitas emergentes (3529,7 ± 722,5) as quais foram significativamente diferentes das flutuantes (3056,5 ± 571,0). Considerando que não houve diferença entre os ambientes, conclui-se que os fatores inerentes aos ambientes analisados não foram preponderantes na determinação da densidade calórica.

The present study examined the influence of the availability of riparian vegetation and C3 emergent aquatic macrophytes on carbon assimilation by Prochilodus lineatus. The vegetal cover of these producers, available at 30 m of the bank, for the terrestrial ecosystem of the rivers Baia, Ivinheima and Parana, was quantified with the image processing Landsat 5 TM, of the year 2000, period of sampling of the biological material at each river. The assimilation of the energy sources (riparian vegetation and C3 aquatic macrophytes, C4 aquatic macrophytes, periphyton, and phytoplankton) by P. lineatus was determined by analysis of stable carbon isotopes (δ 13 C). The area of vegetal cover was estimated at 1,017 km 2 in the Ivinheima river, 669 km 2 in the Parana river, and 268 km 2 in the Baia river. The assimilation of the carbon from riparian vegetation and aquatic macrophytes was proportional to the availability in the environment, but these producers were not the main source of carbon for P. lineatus. Thus, in the rivers with greater vegetation cover, consequently, these items had higher availability in the water body becoming an important carbon source for the species maintenance.