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Recent Submissions

  • Impacto do barramento de um rio amazônico nos padrões espaciais e temporais da diversidade beta fitoplanctônica.

    Zanon, Felipe Morais (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    Human activities have caused degradation of aquatic ecosystems and reduced biodiversity. The dams in particular directly impact the spatial and temporal variation of aquatic communities, and especially the phytoplankton community that responds quickly and efficiently to changes in the environment. The impact of a dam in an Amazon river (Jirau Hydroelectric Power Plant) on the spatial and temporal variation of the composition (beta diversity) of phytoplankton was investigated, from October 2009 to July 2017. The hypothesis was tested that the bus modifies beta diversity on a local and regional scale, and alters each location's contribution to beta diversity. The contribution of the sites to the beta diversity was evaluated as a function of the distance from the bus and the environmental heterogeneity. The phytoplankton composition was different between the phases before, fill and after the damming. Biotic homogenization was verified in the tributaries closest to the dam. The more distant sites presented greater contribution to diversity, but were associated with lower values of richness. The dam caused unidirectional changes, locally and regionally, that is, the community moved to a new state over time, and also caused biotic homogenization locally. The impact of the dam was observed only on the tributaries, indicating that run-of-river dams have a greater impact on the tributaries than on the main channel.
  • Impacto do barramento de um rio amazônico sobre os padrões de sincronia de grupos funcionais fitoplanctônicos.

    Campos, Beatriz Melissa (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    The degree at which populations are correlated in space is called spatial synchrony and can be affected by interspecific interactions, dispersion, and large-scale environmental factors, i. e. Moran effect. The study of this phenomenon can help understanding the temporal stability of communities and the underlying mechanisms. The influence of damming in a river from the Amazon basin (Santo Antônio do Jari HPP) on the synchrony of the environment and the phytoplankton community was evaluated, both for the total density and for different Reynolds functional groups. Was investigated whether the effects would be similar for the main channel (Jari River), tributaries, and for the total area (Jari + tributaries). The mean synchrony values and the confidence intervals of each abiotic variable, functional group, and the total density were estimated for the total area, Jari River and tributaries. Matrix-based multiple regression were also performed to identify the most important drivers of synchrony of the phytoplankton. Changes in the synchrony patterns were verified after the damming. The temporal dynamics of environmental variables, total density and of some functional groups was more synchronous when considering only the Jari River, than the total area or only tributaries. Environmental synchrony and environmental distance were the main mechanisms behind synchrony for some functional groups.
  • Descrição de sete novas espécies e dois novos gêneros de Physocypria sensu latu (Crustacea, Ostracoda) de planícies de inundação brasileiras.

    Almeida, Nadiny Martins de (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    We describe seven new species of Physocypria sensu latu from three of the main Brazilian floodplains: Gen. 1 spec. A gen. et spec. nov. and Gen. 1 spec. B gen. et spec. nov. from the Upper Paraná River floodplain and the South Matogrossense Pantanal, Gen. 2 spec. C gen. et spec. nov., Gen. 1 spec. D gen. et spec. nov. and Gen. 2 spec. E gen. et spec. nov. from the South Matogrossense Pantanal only and Gen. 1 spec. F gen. et spec. nov. and Gen. 1 spec. G gen. et spec. nov. only from the Amazon River floodplain. All new species here described were found in sexual populations. Generally, the new species have a short and suboval carapace, with the left valve overlapping the right valve on all sides, except for the dorsal side in some species. The morphology of hemipenis and prehensile palps, together with the shape of the valves, were most important to distinguish the species. However, several other morphological characters from limb chaetotaxy are discussed, e.g., the absence in all new species of the short accompanying seta of the five natatory setae on antenna; the presence in all new species of a long seta next to the two a-seta on the first thoracopod and the presence/absence or length of specific setae on second and third thoracopod. We discuss the taxonomic position of the seven new species by evaluating the validity of extant genera, especially of Keysercypria Karanovic, 2011, and foreshadow that our seven new species represent two new genera of Cyclocypridinae.
  • Relação entre a complexidade estrutural de macrófitas e os atributos da assembleia de peixes em um reservatório Neotropical.

    Dal Vesco, Bianca Morelatto (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    Habitat complexity is one of the main factors determining biological diversity and its assessment is a challenge that involves several variables. Submerged macrophytes are responsible for changes in habitat complexity and may enhance habitat conditions for different species. These plants usually colonize natural and artificial lentic environments, such as reservoirs, which have abiotic characteristics favorable to their establishment. The construction of the Itaipu Dam and the filling of the reservoir favored the establishment of macrophytes due to changes in flow dynamics. Therefore, the aim of this work was to evaluate whether habitat complexity, provided by macrophytes, is associated with changes in fish assemblage attributes (abundance, richness, and evenness) and composition. Linear regression models were applied to test the relationship between abundance, richness, and evenness with habitat complexity (expressed as macrophyte density - g/m²). In addition, Principal Coordinates Analysis (PCoA) and Spearman correlations were used to assess changes in the composition of fish assemblages according to macrophytes density. The results indicate a direct relationship between habitat complexity and fish assemblage attributes as well as associations between macrophyte density and fish assemblage composition, improving the knowledge about species preference for different levels of complexity. Thus, it is important to consider the behavior of species known to cause economic and ecological issues for future management and conservation efforts.
  • Alteração da concentração de nutrientes causada por P. ambrosettii afeta relação entre macrófita invasora H. verticillata e nativa E. najas: uma abordagem experimental.

    Reinas, Gabriela Cassia Zanon (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    Non native species can negatively affect the invaded environment. Often, these species have biological characteristics that benefit other non natives and facilitate their invasion, so knowing the facilitation mechanisms between invaders are useful to mitigate their damage to the ecosystem. Thus, in this study we tested the hypothesis that Pterygoplichthys ambrosettii, a non native catfish, has habits that can alter nutrient concentrations (phosphorus and nitrogen) in the water column, and positively affect the growth of an invasive macrophyte species in detriment of a native one, characterizing ecological facilitation among invasive species. Therefore, an experiment was conducted with six treatments and four replicas, using the invasive macrophyte Hydrilla verticillata and the native Egeria najas, in the presence and absence of P. ambrosettii, all with occurrence recorded in the upper Paraná River floodplain. The results showed that the treatments with P. ambrosettii had a lower amount of dissolved oxygen, higher electrical conductivity, higher concentration of chlorophyll-a, total phosphorus (TP) and inorganic nitrogen (NI). Macrophyte biomass was significantly higher in monoculture treatments with fish, with this effect being more intense for H. verticillata. When in the same treatment, in the absence of P. ambrosettii, H. verticillata showed greater biomass than E. najas, but with the fish presence, the macrophyte species did not differ in their biomass, indicating that the high concentration of nutrients makes the coexistence of these macrophytes possible. The results found will be useful for future actions to manage invasive species, especially in habitats where they co-occur.
  • Mudanças globais: avaliando as interações entre CO2, eutrofização e espécies não nativas em ecossistemas aquáticos continentais.

    Hein, Gabriela Sponchiado (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    Ecosystems respond to the direct, indirect and synergistic effects of global changes caused by human activity. The understanding of the impacts of these changes and especially of the interaction between the impacts is still limited, especially for aquatic environments, because the interaction between them is rarely considered in environmental studies and assessments. We conducted a systematic literature review on the combination of the factors (i) increase of CO2, (ii) eutrophication and (iii) non-native species to verify how these factors have been considered in the context of climate change in freshwater ecosystems studies. Through the Web of Science database, we searched for articles published in English, up to 2020. Following the PRISMA protocol, 62 articles were analyzed. Only 8% of them addressed the combination of the three factors, among them, eutrophication was the most evaluated global change. Still, the studies do not seem to be looking for answers in a broad way and covering several ecological aspects, since they are concentrated in specific regions such as the Netherlands and United States (44%). Studies most focus on one type of environment, the lentic; use organisms from the base of the food-web; apply the experimental approach; evaluate one organizational level (community) and one response variable (biomass). We identified that the effect of the combination of factors is rarely classified with the terms synergistic and antagonist, even when the authors find these patterns. Our main findings reveal that little attention has been given to the combination of factors in freshwater ecosystems. We also find that when interactions are considered, non-native species tend to be favored and algal blooms intensified (74%). Considering that one of the major challenges is to understand how the interaction between global change factors will affect ecosystems, the combinations of factors still need to be prioritized in studies of aquatic ecosystems.
  • DNA barcoding de Platanichthys platana (Regan, 1917) (Clupeiformes, Clupeidae) de diferentes bacias hidrográficas.

    Ramos, Laura Ivana (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    South America has fish endemic to continental fresh waters, but derived from clades predominantly and ancestrally distributed in marine environments, such as Platanichthys platana. This species is considered the smallest sardine of the Clupeidae with its type locality in the La Plata river. In 2007, there were the first records of P. platana in the upper Paraná river basin and in 2012 in the upper Paraná river floodplain. The variation in the length of specimens from this basin generated curiosity about their identity and origin of introduction. Sequences from the COI region of the specimens were used for genetic distance calculations, construction of gene trees and haplotype networks. The results obtained indicate that all analyzed specimens belong to P. platana. Eight haplotypes were found, some exclusive to the coastal basins of Santa Catarina, Rio Grande do Sul and Negro river basin. The basins of the La Plata river, the Lago and the upper Paraná river floodplain shared different haplotypes. The phylogeographic pattern presented in this study can be justified by the presence of populations of P. platana in the same paleoarea, before the geological process that configured the current architectures of the observed basins, by vicariance. During the Mesozoic and Cenozoic several vicarious events occurred between the coastal watersheds of Brazil that can be attributed to marine regressions and transgressions by continental lands. It is also assumed that specimens from the upper Paraná river floodplain were introduced to the region from Argentine regions.
  • Filogeografia como escopo para explorar a invasão em Ludwigia (Onagraceae) de ambientes não nativos.

    Silva, Adrian Cesar da (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    Ludwigia has some invasive macrophyte species that have not yet been explored under the scope of phylogeography, a promising area to understand the ecology of invasions using barcode molecular markers sensitive to intraspecific variations. Thus, it was theorized that barcode markers used in invasive species of Ludwigia occurring in non-native regions would be phylogeographically informative. Sequences of the molecular markers trnH-psbA, rbcL, matK and phyC from invasive populations of L. peploides and L. grandiflora were used as they are the only ones available in Genbank. A gene tree was generated by the Neighborn-Joining method and a haplotypic network by the Median-Joining method for each species. The trnH-psbA marker was the only phylogeographically informative marker for detecting intraspecific variations in the analyzed taxa. Three haplotypes were detected for L. grandiflora and two haplotypes for L. peploides. Three geographically distinct founder populations of L. grandiflora were introduced in Europe, with Hg1 shared with the US population, while L. peploides has a founder population in Europe and another in the US. The long history of the introduction of these species in Europe and the limited geographic scope of molecular sampling demonstrate that these data are underestimated. A search in the Web of Science database exposed a paucity of molecular data for invasive species of Ludwigia, highlighting the contribution of the results to the information on these haplotypic relationships in the context of invasive biology. Therefore, the detection of haplotypic diversity of invasive species of Ludwigia proved to be promising when investigated by the phylogeographic scope, supporting a better understanding of the management and ecology of these haplotypes in non-native areas.
  • Caracterização molecular de digenéticos parasitas de gastrópodes (Mollusca) do baixo rio Ivaí, Paraná, Brasil.

    Passere, Mayara Destro (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    Thiarids are pantropical gastropods endemic to South America and are found in lentic and lotic freshwater environments. These gastropods act as intermediate hosts for several species of digeneans. However, it is important to consider that there are difficulties for a correct identification of these digeneans in certain stages of the life cycle since the larvae have a reduced size and few morphological characteristics for diagnosis. In this way, techniques based on molecular markers become an extremely important tool, combining the use of ribosomal and mitochondrial regions. Considering that there are no records in the literature of studies involving parasites and gastropods as intermediate hosts in the Ivaí River, this study is the first regarding these relationships. Seventy-six specimens of gastropods were collected. Of these, 21 were parasitized. As for the parasites, 16 different morphotypes were found. The gastropod DNA was amplified using the COI marker. The gastropods showed genetic similarity with Aylacostoma chloroticum with different percentages of identity. As for the parasites, COI and 28S markers were used for DNA amplification. Four different taxa were characterized with both markers. With the mitochondrial marker it was possible to confirm only one genus among the digeneans found. However, the 28S ribosomal marker proved to be more effective for the identification of Ivaí River parasites, showing higher similarity values in relation to sequences available in the databases and lower values of genetic distance. In this way, it was possible to confirm the classification of the morphotypes into two distinct genera.
  • Neotropical freshwater fishes biogeography: historical and ecological approaches with insights regarding the conservation.

    Frota, Augusto (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    The patterns and processes that cause a system of regionalization of organisms on the planet are historical and ecological hypotheses that biogeography seeks to elucidate. The Neotropical region is home to one of the greatest richness of freshwater fish in the world that exhibit distinct biogeographic patterns based on ecology, systematics, and evolution. Through methodologies within the scope of historical and/or ecological biogeography, the aims of this study are to present new approaches and contributions to the knowledge of the geographic distribution of freshwater fish in this region, investigating the evolutionary biogeography of Cnesterodontini and Anablepidae, as well as the spatial patterns of ichthyofauna beta-diversity in the Ivaí river basin, Paraná State. The results highlighted well-defined scenarios of the hydrological barriers formation, mainly between coastal basins and drainages that flow into the La Plata River system in South America. These findings enabled congruent relationships of biogeographic areas within the proposals for evolutionary diversification to the Neotropical freshwater fishes. Furthermore, dispersal events caused by headwater captures and sea-level changes satisfactorily complemented the biogeographic patterns and area relationships evidenced for other Neotropical fish lineages, showing similar diversification patterns in the Central Brazil drainages and in the Atlantic coast drainages. The results also showed strong spatial segregation of the ichthyofauna throughout the Ivaí River basin (upper Paraná River system) with emphasis on the mutual influences of niche- and dispersal-based processes. These findings can support new theoretical and methodological references for the main mechanisms and patterns specific to the metacommunities of aquatic organisms. Applying the results herein obtained in historical and ecological consonance has great potential to aid an effective management for the conservation of freshwater fish diversity, whether considering lineages with species at high risk of extinction or even river basins of fundamental importance for maintaining biodiversity and ecosystem functionality in continental aquatic environments.
  • Dinâmica da comunidade de Chironomidae (Diptera) em eventos de cheias e secas extremas em um rio Neotropical.

    Favro, Alline (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2021)
    Climate change can make extreme drought and flood events more frequent, while damming large rivers can alter the hydrological regime by making droughts more prolonged and floods less intense. Together, both factors can affect aquatic communities. Here, the variation of Chironomidae community attributes between extreme floods and droughts in a neotropical floodplain river was investigated. The hypothesis that the abundance, richness, diversity and variability attributes of the Chironomidae community are reduced after extreme events was tested. Sampling took place quarterly from 2000 to 2012, although only a few years were selected to investigate our predictions. Twelve sampling periods were selected, which were divided into years in which, El Niño (extreme flood) and La Niña (extreme drought) phenomena occurred. In the Paraná River, three points were determined for the collection of benthic material, in transect: right bank, center and left bank of the river. We recorded 75 morphospecies of Chironomidae. The most common taxa in periods of extreme flooding were Djalmabatista sp 2, Lopescladius sp 1 and Tanytarsus type E. For periods of extreme drought, the most common taxa were Polypedilum (Tripodura) sp 4, Polypedilum sp 3 and Lopescladius sp 1. A composition and attributes of the Chironomidae community in the Paraná River varied between before and after extreme flood and drought events. Attributes such as Shannon-Wiener abundance, richness and diversity were reduced after extreme floods and, in contrast, tended to increase after extreme drought events (except Shannon diversity). Thus, it can be stated that the evaluated flood and drought events, despite being extreme, have different consequences in the Chironomidae community of the Paraná River. Given the environmental and global conditions we experience today, including climate change and dams, extreme events could be even more frequent in aquatic ecosystems. Therefore, it is essential to understand the consequences of extreme flood and drought events on ecosystems with high biodiversity and that provide relevant ecosystem services such as floodplain rivers.
  • Sucessão de macroinvertebrados na decomposição da planta aquática exótica Hydrilla verticillata e da nativa Egeria najas.

    Machado, Saulo Bemhur (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2019)
    Decomposition is a process of great importance to the ecosystem. Macroinvertebrates together with fungi and bacteria play a very important role in the cycling of organic matter. Through decomposition, nutrients that make up the organisms can be reused and macroinvertebrates act by fractionating the organic matter in this process. The exotic species Hydrilla verticillata (L.f) Royle usually causes problems in various regions of the globe such as economic damage in hydroelectric plants. This exotic species competes with native species and can facilitates new invasions. The objective of the present work is to evaluate how the colonization of macroinvertebrates occurs during the decomposition of H. verticillata and E. najas macrophytes, as well as other community attributes during the process such as density, richness, Shannon diversity and Pielou evenness. The experiment was carried out in Garças Lake and the macrophytes were collected in Paraná River. Macrophytes were dried at room temperature and 5 g of each species were added in two types of litterbags, one thin mesh (0.5 mm) and another with thick mesh (4 mm), totalling 100 litterbags. The litterbags were fixed at 5 points in the lake and removed each 4 days. In the laboratory the litterbags were washed with a 0.2 μm mesh sieve, the decomposing material was sorted and the remainder was oven dried for further decay calculation. There was no significant difference in community attributes, except when time was applied assigned to analysis. The decomposition was similar in both species because both had similar characteristics, including phylogenetic proximity. The most observed taxon during the process was Chironomidae. Thus, it is worth noting that more studies are needed to elucidate questions related to the colonization process and quantify the degradation of organic matter of exotic and native species in the Upper Paraná River floodplain.
  • Efeitos de diferentes intensidades de ocupação aquícola sobre a estrutura taxonômica e funcional de assembleias de peixes em riachos Neotropicais.

    Camargo, Mariele Pasuch de (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    Biological invasion processes are complex phenomena and comprise one of the greatest challenges for the conservation of biodiversity in continental aquatic environments. The pressure of propagules, i.e., the number of non-native individuals released and the number of release events, is among the different mechanisms involved in these decisive processes for the successful establishment of non-native species. In this scenario, aquaculture is an important source of propagules of species with high invasive potential, such as Nile Tilapia (Oreochromis niloticus), as accidental escapes and intentional releases from production ponds are recurrent. Nine small streams, tributaries of the Piquiri River (Paraná, Brazil), were sampled to evaluate the effect of aquaculture on fish assemblages in neotropical streams. The watersheds of these streams differ in percentage of aquaculture occupation, and this difference was used as a proxy for propagule pressure of O. niloticus in natural environments. Therefore, the present research aimed to evaluate the effects of different intensities of aquaculture production of tilapia on the richness patterns, composition and structure of the ichthyofauna, testing the hypothesis that the increase in propagule pressure of this species alters the patterns of occurrence and abundance of assemblages, as well as discuss the effects of this species on the functional structure of ichthyofauna, observing the effect of aquaculture occupation on responses of functional diversity indexes and on dissimilarity patterns among the different streams. The results indicated that streams with no aquaculture occupation and with no presence of O. Niloticus had more similar compositions and differed in patterns of occurrence and distribution of ichthyofauna from streams under aquaculture activity. In addition, the presence of tilapia altered the functional diversity indexes in the streams, as the species presented more extreme traits that allow it to increase the functional space of receptor environments and promote greater niche differentiation. The results reinforce the potential of aquaculture as an important source of propagules of non-native species for natural environments and raise attention to the structuring power of tilapia on the taxonomic and functional composition of native ichthyofauna.
  • Índice de Sustentabilidade Ecoambiental de sub-bacias hidrográficas (ISE-sb): para a gestão do alto rio Paraná, Brasil.

    Tomadon, Leonardo da Silva (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2022)
    The assessment of sustainable development in sub-watersheds plays a central role in rationalizing the decisions taken. A promising form of average indicators of this development is through indicators, and when many are used, they are usually aggregated into indices, which provide a simplified and multidimensional view of the system under analysis. Several sustainability indices for watersheds are proposed in the literature. However, incorporation of extraordinary indicators, that biodiversity, a gap is still a major upgrade. Therefore, the use of biodiversity indicators as representative of the environmental dimension constitutes an advance on the indices presented in the literature recently. The objective was to evaluate the sustainability gradient in the hydrographic basins of the Upper Paraná River, through an eco-environmental sustainability index of hydrographic sub-basins (ISE-sb) that incorporates protected ecological. For this purpose, the indicators selected based on the propositions of Agenda 2030 were identified in four dimensions of sustainability, economic, economic, environmental and thought through a process of sustainability: normal and social. Then, the importance of the indicators was considered, using the multi-criteria analysis based on the Hierarchical Process Analysis (HP) method. The ISE-sb was calculated by means of the weighted media between the sub-indices that represent as dimensions. Finally, we apply the Gi* statistic to identify hotspots and coldspots. The results show that among the dimensions of sustainability, the highest was the one that presented a positive amount of low values. The regions located in the eastern portion, or serra do mar, southern portion, and the Federal District formed sustainability hotspots, while the sub-basins located in the states of Goiás, Mato Grosso do Sul and Minas Gerais formed the sustainability coldposts. A sustainable spatial planning of the hydrographic sub-basins is recommended, adopting cold areas as priorities for sustainability. It highlights the main methodological limitation, a potential reproducibility of the tool in other spaces.
  • Gastrópodes não nativos de água doce: uma revisão sistemática global e distribuição potencial de duas espécies problemáticas.

    Tramonte, Rafael Prandini (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2021)
    Ecological studies in all environments of the world the effects of non-native species in various parts of the world are discussed. Regarding the invasion of these environments, we highlight the Phylum Sanitary, especially the ecological Mollusa, for presenting numerous gastronomic classes, with many species with potential, which can lead to as many sanitary, as well as sanitary and graves, in places of invasion. Know the invasive species that are reported in their scientific distribution, in this case introduction and the main ones are reported, is of fundamental importance. Knowing the risk of introducing an invasive species, and its impacts on the invaded places, it is necessary to find ways of prevention. A precious tool of meaning is an invasion of the invasive potential of one, thus generating a risk that indicates the suitability of the habitat or probability of occurrence based on the environmental conditions of the native area and the area in which the species may become invasive. . In this way, the adequacy of the invasive Melanoides tuberculata against a native species by Biomphalaria glabra, which is also a species with potential to cause toilets, is of fundamental importance, to predict possible invasion sites, and if the species are competing for the same ecological niches. Thus, the present work is subdivided into two works that address issues such as: a systematic of scientific articles about invasive freshwater gastropods. The second work will address the modeling of the current and future potential distribution of two problematic gastropod species in South America.
  • Padrões de distribuição espacial das assembleias de peixes em reservatórios neotropicais.

    Ganassin, Maria Julia Mileo (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2021)
    Given the great diversity of Neotropical fish species, as well as the importance of such organisms as a link within aquatic food chains, it is essential to assess different processes that drive the spatial organization of their communities. It is known that the structure of fish assemblages varies markedly in relation to space, depending on abiotic factors, biotic interactions, and dispersion processes. However, these determining factors in the structuring of fish communities vary indiscriminately in dammed aquatic bodies. The course of large rivers has been altered due to the construction of reservoirs and the number of projects under construction or inventoried has been increasing significantly in recent decades. Therefore, evaluating how the spatial organization of fish assemblages occurs in environments (i.e., dammed), as well as unraveling the predictors associated with this organization is of extremely important for conservation purposes and the implementation of management measures. To investigate such aspects in dammed environments, in the first study three cascades of reservoirs belonging to different hydrographic basins were studied, in which the effects of these reservoirs arranged in series on the patterns of diversity, distribution and richness of the assemblages were evaluated. In the second study, 29 reservoirs located in the state of Parana were evaluated in order to identify relationships between the organization of fish trophic guilds and environmental, spatial and morphological predictors. The results found suggest that, in most of the studied environments, the environmental changes caused by the construction of dams, as well as their morphological characteristics and modes of operation have negative effects on the diversity, distribution and abundance of fish species and exert an influence on the different fish trophic guilds.
  • Preditores abióticos e bióticos da abundância de uma macrófita nativa e uma macrófita invasora em um reservatório subtropical.

    Florêncio, Fernanda Moreira (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2021)
    The invasion success of non-native species depends on several factors, and native populations and biotic characteristics of non-native environments can offer resistance to non-native species development. Reservoirs can facilitate submerged macrophyte invasion once it modifies the environment and provides favorable abiotic conditions to macrophyte establishment and development. However, previous colonization of native species can resist the development of invasive ones through priority effects. In this investigation we used large data-set (1120 samplings during 4 years) obtained in the Itaipu Reservoir (Brazil/Paraguay) to assess the relationship between the abundance of the native submerged macrophyte Egeria najas and of the invasive Hydrilla verticillata and the water level, littoral slope and Secchi disk depth. We also investigated how the concomitant and previous abundance of both macrophytes correlates. A spatial-temporal modeling was applied using Integrated Nested Laplace Approximations method, which controls the effect of spatial-temporal autocorrelation. Our results indicate an important role of water transparency, littoral slope and water level oscillations (in terms of amplitude and increased hydrometric level), in a short period of time (30 days) for the temporal dynamics of the abundance of both species. However, alterations of the hydrometric levels and of the littoral slope affected H. verticillata to a greater extent than E. najas. In addition, the abundance of each species was related with its own abundance in previous samplings, highlighting the importance of vegetative propagule pressure and resistance structures for population recovery. The magnitude of the interaction between both species in concomitant occurrence in the same site was abundance dependent.
  • Padrões de diversidade β em ecossistemas aquáticos em diferentes escalas espaciais e temporais.

    Diniz, Leidiane Pereira (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2021)
    Species are heterogeneously distributed and environmental changes, such as the construction of dams or extreme climate events, can modify the dynamics of aquatic organisms. Understanding the processes that drive diversity, across long time periods, can help in the establishment of increasingly accurate conservation measures. This thesis evaluated the patterns of β diversity and metacommunity structure at different spatial and temporal scales in three independent studies in the Upper Paraná river floodplain, Brazil. The first analyzed the seasonal variation of zooplankton β and Elements of Metacommunity Structure [EMS] of zooplankton, over four years (two years of prolonged drought and two years of extreme flooding), and on a smaller (sub-basins) and a larger scale (floodplain). Regardless of the hydrological period and spatial scale, zooplanktonic metacommunity structure remained practically constant throughout the four years, with the predominance of the Clementsian pattern. The predominance of the Clementsian pattern suggests that the associations of zooplankton species in the floodplain responded similarly to the environmental gradient and that the responses differed among species groups. In the second, the taxonomic (LCBD-t) and functional (LCBD-f) ecological uniqueness of zooplankton over 19 years was determined in lakes and lotic systems of two sub-basins (dammed and free-flowing), in addition to investigating which processes (temporal, environmental and biological) drive LCBD-t and LCBD-f. Regardless of the characteristics of each sub-basin, the highest LCBD-t and LCBD-f were related to lower species and trait richness, respectively. The temporal processes were the main drivers of the ecological uniqueness of zooplankton, and they were more important than the biological processes (phytoplankton biovolume and fish biomass, representing food resource and potential predation, respectively). Finally, it was tested whether, in a dammed sub-basin, a prolonged drought makes aquatic metacommunities (phytoplankton, zooplankton, and fish) more similar over time than a period that includes extreme flood events. Only zooplankton underwent homogenization during this period. The β diversity of phytoplankton and fish did not change between different hydrological periods, indicating that the dispersion type (passive or active) does not interfere with drought homogenization. The response between the biological groups was different, reinforcing that the groups are not surrogates of each other. The greater β diversity in the period with extreme floods shows, at least for zooplankton, the importance of the flood pulse, reducing the negative effects of prolonged drought in a dammed sub-basin. The results showed the predominance of a metacommunity pattern resulting from high turnover (Clementsian), indicating that conservation measures should include a greater number of sites, including those with less richness, as they may have a different composition (> LCBD). We also emphasize the importance of considering different scales, as each can provide unique insights. It is important that biodiversity studies consider β diversity to understand the mechanisms that drive the metacommunity in the face of environmental changes, especially over longer time scales.
  • De monitoramentos locais até um inventário global das introduções de macrófitas aquáticas – insights para monitoramento e prevenção de invasões de espécies.

    Dainez Filho, Mário Sérgio (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2021)
    Aquatic ecosystems are especially vulnerable to species invasion due to their extent, diversity of habitats, and inherent dynamics. Invasive aquatic macrophytes are of great concern because of their great influence on aquatic ecosystems. In this thesis, we sought to contribute to the field of biological invasions of aquatic macrophytes at regional and global levels using knowledge pertinent to monitoring and preventing the introduction of species. Given that, one of the most concerning invasive species in the world, Hydrilla verticillata (L.f.) Royle, was evaluated in different types of environments in a subtropical floodplain. The relationship of occurrences of this species with its main abiotic predictors was investigated, as well as its relationship with the native (equivalent) species Egeria najas Planch. right after its detection and 10 years later. This work contributed with insights regarding the biotic interactions of invaders and natives as well as changes in environmental predictors that highlight anthropogenic impacts that deserve attention. A second work was carried out to leverage knowledge about invasive aquatic macrophytes at a global level. A compilation of data from several available sources was carried regarding the most common pathways of introduction of aquatic macrophytes to identify the regions of origin and destination of these species and their respective functional groups. Such information is crucial for the determination of public policies and management strategies to avoid the introduction of unwanted species. In summary, this thesis helps the characterization of aquatic macrophyte invasions aiming at their prevention.
  • Impactos da mudança climática sobre ostrácodes de água doce (Crustacea, Ostracoda).

    Conceição, Eliezer de Oliveira da (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2021)
    Species are exposed to natural climate change throughout their evolutionary history. However, anomalous global warming and resulting variations in rainfall patterns affect survival, alter the distribution of organisms and the network of species interactions. The aim of this thesis was to find larger-scale (basin and biome level) patterns for the possible effects of climate change on the distribution of South American freshwater ostracods through ensemble analysis of several species-distribution modelling algorithms. Here, climate change was based on two assumptions of increasing carbon emissions, the moderate-optimistic (RCP 4.5) and pessimistic (RCP 8.5) scenarios of four climate models (AOGCMs), from 2050 and 2080. In the first approach, projections of changes in ostracod species richness and composition were presented, and conservation status of 61 species from 13 river basins in the Southern Cone. In the second approach, the geographical pattern of a symbiotic interspecific interaction of commensalism type was evaluated through the climatic suitability of Elpidium (Ostracoda) and tank bromeliads of the Atlantic Forest, and the availability of habitat for Elpidium (presence of tank bromeliads) in the future. For both approaches, climate change directly influenced the decrease in future distribution areas of ostracods. The results of the first approach showed a decrease in ostracod richness in the Southern Cone basins of South America, and different species compositions in 2050 and 2080, in both the moderate-optimistic and pessimistic scenarios. The decrease in the ranges of ostracods will change the conservation status of several species to “potentially threatened”. Elpidium ranges will be more limited in the future, and there will be less habitat availability, i.e. fewer tank bromeliad species for interaction. In general, precipitation and temperature regimes are synchronized with phenological life-history events of the species, which determine the direction of dispersal to the environmental set of optimal survival conditions in the future. Our results contribute to the inclusion of ostracods (and other invertebrates) in conservation plans for their habitats on larger geographical scales.

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