No presente trabalho, investigamos a associação entre a fauna de macroinvertebrados e o folhiço em riachos de montanha da região sul do Estado de São Paulo. Os principais objetivos da tese foram: caracterizar o folhiço e a fauna de macroinvertebrados associada em mesohábitats de remanso e de corredeira (Capítulo 1); testar os efeitos das características das folhas sobre o seu processamento e sobre a fauna de macroinvertebrados aquáticos (Capítulo 2); acompanhar o processo de degradação de folhas de espécies vegetais com diferentes características físicas (resistência foliar) e químicas (conteúdo de fenóis totais), bem como estudar a sua colonização pela fauna de macroinvertebrados (Capítulo 3). A densidade, riqueza padronizada de táxons e composição faunística de macroinvertebrados associados ao folhiço apresentaram variação entre remanso e corredeira, porém esta relação esteve condicionada ao tamanho do riacho. Os compostos fenólicos e a resistência foliar isoladamente não influenciaram a degradação do folhiço, e não houve efeito da riqueza de espécies vegetais sobre a perda de massa foliar. A densidade, riqueza padronizada e composição faunística de macroinvertebrados não foram influenciadas pelas características estruturais e químicas iniciais das plantas; possivelmente, outras características químicas das espécies vegetais que não foram consideradas no presente trabalho podem ter sido mais importantes para explicar estes componentes da fauna. Houve um aumento da densidade de macroinvertebrados ao longo do tempo, no entanto, a densidade não foi afetada pela espécie vegetal. A riqueza não foi afetada por nenhum dos dois fatores. Por outro lado, foi possível observar um forte gradiente de composição faunística ao longo do tempo, o qual foi dependente do tipo de folha. / In this work we investigated the link between the macroinvertebrate fauna and litter detritus in forested mountain streams, in the southern São Paulo State. The main goals of this thesis were: to describe litter detritus and its associated macroinvertebrate fauna in riffles and pools (Chapter 1); to test the effects of leaf properties on litter processing and on the aquatic macroinvertebrate fauna (Chapter 2); to follow the processing of litter from plant species with different structural (leaf toughness) and chemical (total phenolic compounds) features, as well as the colonization by macroinvertebrates fauna (Chapter 3). Density, standardized taxonomic richness and faunal composition of macroinvertebrates found in litter showed variation between riffles and pools, although this relationship was subject to stream size. Phenolic compounds and leaf toughness alone did not influence litter decomposition, and no effect of leaf species diversity was found for leaf mass loss. Density, standardized taxonomic richness and faunal composition of macroinvertebrates were not affected by structural or chemical features of the litter; it is likely that other chemical aspects of the leaves might have played a more important role. We observed an increase in macroinvertebrate density throughout time, however, density was not dependent of leaf species. Taxonomic richness was not affected either by time or plant species. On the other hand, we observed a strong gradient for faunal composition along time, and this association showed an interaction with leaf species.

Hemlock woolly adelgid is an invasive herbivore causing extensive mortality of eastern hemlock, an important foundation species that provides stable conditions influencing biological communities. Hemlock is often found in riparian areas and following its decline, broadleaved species, including birch, beech, and rhododendron, will replace it. These plants differ from hemlock in patterns of canopy cover and leaf properties, which influence conditions and resources within streams. My goal was to evaluate potential impacts of adelgid-induced alterations to riparian canopies and litter on benthic communities and litter breakdown in streams. I characterized benthic invertebrate communities, litter colonization and litter breakdown in streams with hemlock- or deciduous-dominated riparian canopies. Riparian canopy influenced abundance of some invertebrates, but litter species influences a range of benthic colonizers. Rhododendron and beech litter generally support more invertebrates and decomposes more slowly than birch or hemlock. When invertebrates are excluded, broadleaved litter breakdown is more hindered than hemlock breakdown. My findings suggest that invertebrates may be more affected by future increases in broadleaved litter inputs to streams than by hemlock litter loss. This is significant because benthic invertebrates are important for in-stream litter processing and are linked to aquatic and terrestrial food webs.

No presente trabalho, investigamos a associação entre a fauna de macroinvertebrados e o folhiço em riachos de montanha da região sul do Estado de São Paulo. Os principais objetivos da tese foram: caracterizar o folhiço e a fauna de macroinvertebrados associada em mesohábitats de remanso e de corredeira (Capítulo 1); testar os efeitos das características das folhas sobre o seu processamento e sobre a fauna de macroinvertebrados aquáticos (Capítulo 2); acompanhar o processo de degradação de folhas de espécies vegetais com diferentes características físicas (resistência foliar) e químicas (conteúdo de fenóis totais), bem como estudar a sua colonização pela fauna de macroinvertebrados (Capítulo 3). A densidade, riqueza padronizada de táxons e composição faunística de macroinvertebrados associados ao folhiço apresentaram variação entre remanso e corredeira, porém esta relação esteve condicionada ao tamanho do riacho. Os compostos fenólicos e a resistência foliar isoladamente não influenciaram a degradação do folhiço, e não houve efeito da riqueza de espécies vegetais sobre a perda de massa foliar. A densidade, riqueza padronizada e composição faunística de macroinvertebrados não foram influenciadas pelas características estruturais e químicas iniciais das plantas; possivelmente, outras características químicas das espécies vegetais que não foram consideradas no presente trabalho podem ter sido mais importantes para explicar estes componentes da fauna. Houve um aumento da densidade de macroinvertebrados ao longo do tempo, no entanto, a densidade não foi afetada pela espécie vegetal. A riqueza não foi afetada por nenhum dos dois fatores. Por outro lado, foi possível observar um forte gradiente de composição faunística ao longo do tempo, o qual foi dependente do tipo de folha. / In this work we investigated the link between the macroinvertebrate fauna and litter detritus in forested mountain streams, in the southern São Paulo State. The main goals of this thesis were: to describe litter detritus and its associated macroinvertebrate fauna in riffles and pools (Chapter 1); to test the effects of leaf properties on litter processing and on the aquatic macroinvertebrate fauna (Chapter 2); to follow the processing of litter from plant species with different structural (leaf toughness) and chemical (total phenolic compounds) features, as well as the colonization by macroinvertebrates fauna (Chapter 3). Density, standardized taxonomic richness and faunal composition of macroinvertebrates found in litter showed variation between riffles and pools, although this relationship was subject to stream size. Phenolic compounds and leaf toughness alone did not influence litter decomposition, and no effect of leaf species diversity was found for leaf mass loss. Density, standardized taxonomic richness and faunal composition of macroinvertebrates were not affected by structural or chemical features of the litter; it is likely that other chemical aspects of the leaves might have played a more important role. We observed an increase in macroinvertebrate density throughout time, however, density was not dependent of leaf species. Taxonomic richness was not affected either by time or plant species. On the other hand, we observed a strong gradient for faunal composition along time, and this association showed an interaction with leaf species.

A wetland passive treatment system (PTS) was used to treat mine effluent flowing into East Prong Creek, Virginia. Prior to treatment, copper concentrations in the stream ranged from 8.9 to 32.0 μg/L at the impacted sites and from 0.1 to 7.7 μg/L at the reference site. In kick samples, insect abundance (n) and the number of taxa (#) were reduced at the impacted sites (n = 31, 22, 33, 24 and # = 190, 246, 266, 345, at sites 2 - 5, respectively) relative to the reference site (n = 52, # = 973). Red maple (Acer rubrum) leaves broke down twice as fast at the reference site (k = -0.029) than at sites receiving the untreated effluent (k = -0.016, -0.013, -0.013, -0.013 at sites 2 - 5, respectively). In benthic samples and leaf packs, abundances of all functional groups were reduced at the impacted sites relative to the reference site. In terms of abundance, scrapers and predators were most and least affected by copper, respectively. Following treatment, copper concentrations at the impacted sites in East Prong Creek ranged from 0.1 to 14 μg/L. The wetland PTS was most effective at reducing metal concentrations in the effluent from July to December, when dissolved oxygen concentrations in and flow through the wetland cells were low. Functional recovery preceded recovery of community structure by at least six months. Decomposition rates were similar at all sites in Fall 1994, after six months of treatment (k = -0.012, -0.011, -0.011, -0.012, -0.012) at sites 1 - 5, respectively). Recovery of community structure was not complete after 1 year of treatment. Abundance of collector-filterers and predators recovered quickly following treatment, while recovery of collector-gatherers and shredders was slower. / Master of Science

A decomposição da serapilheira é um processo fundamental, que influencia o armazenamento de carbono (C) no solo e a disponibilidade de nutrientes para as plantas e os microrganismos, afetando assim a distribuição de espécies em um ecossistema. A Floresta Ombrófila Densa, conhecida popularmente como Mata Atlântica localiza-se ao longo da costa brasileira e é caracterizada pela elevada diversidade e endemismo. Dentre as diversas famílias botânicas presentes neste ecossistema, a família Fabaceae apresenta grande importância, tanto pela sua abundância e ampla distribuição, como por desempenhar um papel importante no ciclo do nitrogênio (N) terrestre. O objetivo deste estudo foi investigar as taxas de decomposição e mudanças na composição inorgânica e orgânica da serapilheira ao longo desse processo em duas fisionomias de florestas (Terras Baixas vs. Montana) localizadas em diferentes altitudes (100 m vs. 1000 m). Levantamentos realizados em diferentes formações vegetais da Floresta Ombrófila Densa ao longo de um gradiente altitudinal indicam diferenças significativas na disponibilidade de N nos solos em diferentes altitudes, além de diferenças contrastantes na temperatura do ar. Essas diferenças podem influenciar na composição das folhas, que por sua vez interfere no processo de decomposição. Os experimentos com litter bags foram instalados no início do período seco e outro no início do período chuvoso, com duração de um ano cada um. As espécies selecionadas para esse estudo pertencem a família Fabaceae (Inga lanceifolia e Swartzia simplex var. grandiflora), e foram comparadas a uma espécie pertencente a família Monimiaceae (Molinedia schottiana). A taxa de decomposição e a degradação da lignina, celulose, hemicelulose e do nitrogênio foram mais rápidos na leguminosa da floresta de Terras Baixas em comparação a não-leguminosa. Por outro lado, não houve diferença nas taxas de decomposição entre I. lanceifolia e M. schottiana da floresta Montana. Mas, comparando a espécie M. schottiana, a não-leguminosa comum nas duas altitudes, esta espécie se decompôs mais rapidamente na floresta de Terras Baixas em relação a Montana. Na floresta de Terras Baixas, não só as temperaturas mais elevadas, mas também as diferentes característica químicas, como o elevado teor de N e a baixa razão C:N na serapilheira da leguminosa podem acelerar os processos de decomposição nesta floresta, além disso, a menor concentração de polifenóis na M. schottiana a 100 m comparada a 1000 m de altitude também pode ter favorecido as elevadas taxas de decomposição na floresta de Terras Baixas. Portanto, as características químicas da serapilheira também parecem regular as taxas de decomposição / Litter decomposition is a fundamental process that affects carbon (C) storage in the soil and nutrients availability for plants and microorganisms, impacting the distribution of species in a given ecosystem. The Dense Ombrophilous Forest, commonly known as Atlantic Forest, is located along the Brazilian coast and characterized by its high diversity and endemism. Among many botanic families existing in this ecosystem, the Fabaceae family has great importance because it is very abundant and well distributed and also plays an important role in the terrestrial nitrogen (N) cycle. The objective of this study was to investigate decomposition rates and changes in inorganic and organic litter composition throughout this process in two forest physiognomies (Lowland vs. Montane) located in different altitudes (100 m vs. 1000 m). Studies realized along an altitudinal gradient in different vegetation formations of Dense Ombrophilous Forest indicate significant differences in N availability in the soil of different altitudes, and contrasting differences in air temperature. These differences can influence leaf decomposition, which interferes in the decomposition process. One of the experiments with litter bags were set at the beginning of the dry season and another at the beginning of the wet season, each one with duration of one year. The species selected for this study belong to the Fabaceae family (Inga lanceifolia and Swartzia simplex var. grandiflora) and were compared to another species of the Monimiaceae family (Molinedia schottiana). The decomposition rates, lignin, cellulose, hemicellulose and nitrogen degradation were faster in legume than non-legume in Lowland forest. On the other hand, there was no difference in decomposition rates between M. schottiana and I. lanceifolia in Montane forest. But, comparing M. schottiana specie, a common non-legume in the two altitudes, this specie decomposed faster in Lowland than Montane forest. In Lowland forest, not only higher temperatures, but also the different chemical characteristics, such as high nitrogen content and low C:N ratio in the legume litter could accelerate the decomposition processes in this forest, in addition, lower polyphenols concentration in M. schottiana in Lowland compared to Montane forest can also favored the high decay rates in Lowland forest. Therefore, the litter chemical characteristics also appear to regulate the decomposition rates

A decomposição da serapilheira é um processo fundamental, que influencia o armazenamento de carbono (C) no solo e a disponibilidade de nutrientes para as plantas e os microrganismos, afetando assim a distribuição de espécies em um ecossistema. A Floresta Ombrófila Densa, conhecida popularmente como Mata Atlântica localiza-se ao longo da costa brasileira e é caracterizada pela elevada diversidade e endemismo. Dentre as diversas famílias botânicas presentes neste ecossistema, a família Fabaceae apresenta grande importância, tanto pela sua abundância e ampla distribuição, como por desempenhar um papel importante no ciclo do nitrogênio (N) terrestre. O objetivo deste estudo foi investigar as taxas de decomposição e mudanças na composição inorgânica e orgânica da serapilheira ao longo desse processo em duas fisionomias de florestas (Terras Baixas vs. Montana) localizadas em diferentes altitudes (100 m vs. 1000 m). Levantamentos realizados em diferentes formações vegetais da Floresta Ombrófila Densa ao longo de um gradiente altitudinal indicam diferenças significativas na disponibilidade de N nos solos em diferentes altitudes, além de diferenças contrastantes na temperatura do ar. Essas diferenças podem influenciar na composição das folhas, que por sua vez interfere no processo de decomposição. Os experimentos com litter bags foram instalados no início do período seco e outro no início do período chuvoso, com duração de um ano cada um. As espécies selecionadas para esse estudo pertencem a família Fabaceae (Inga lanceifolia e Swartzia simplex var. grandiflora), e foram comparadas a uma espécie pertencente a família Monimiaceae (Molinedia schottiana). A taxa de decomposição e a degradação da lignina, celulose, hemicelulose e do nitrogênio foram mais rápidos na leguminosa da floresta de Terras Baixas em comparação a não-leguminosa. Por outro lado, não houve diferença nas taxas de decomposição entre I. lanceifolia e M. schottiana da floresta Montana. Mas, comparando a espécie M. schottiana, a não-leguminosa comum nas duas altitudes, esta espécie se decompôs mais rapidamente na floresta de Terras Baixas em relação a Montana. Na floresta de Terras Baixas, não só as temperaturas mais elevadas, mas também as diferentes característica químicas, como o elevado teor de N e a baixa razão C:N na serapilheira da leguminosa podem acelerar os processos de decomposição nesta floresta, além disso, a menor concentração de polifenóis na M. schottiana a 100 m comparada a 1000 m de altitude também pode ter favorecido as elevadas taxas de decomposição na floresta de Terras Baixas. Portanto, as características químicas da serapilheira também parecem regular as taxas de decomposição / Litter decomposition is a fundamental process that affects carbon (C) storage in the soil and nutrients availability for plants and microorganisms, impacting the distribution of species in a given ecosystem. The Dense Ombrophilous Forest, commonly known as Atlantic Forest, is located along the Brazilian coast and characterized by its high diversity and endemism. Among many botanic families existing in this ecosystem, the Fabaceae family has great importance because it is very abundant and well distributed and also plays an important role in the terrestrial nitrogen (N) cycle. The objective of this study was to investigate decomposition rates and changes in inorganic and organic litter composition throughout this process in two forest physiognomies (Lowland vs. Montane) located in different altitudes (100 m vs. 1000 m). Studies realized along an altitudinal gradient in different vegetation formations of Dense Ombrophilous Forest indicate significant differences in N availability in the soil of different altitudes, and contrasting differences in air temperature. These differences can influence leaf decomposition, which interferes in the decomposition process. One of the experiments with litter bags were set at the beginning of the dry season and another at the beginning of the wet season, each one with duration of one year. The species selected for this study belong to the Fabaceae family (Inga lanceifolia and Swartzia simplex var. grandiflora) and were compared to another species of the Monimiaceae family (Molinedia schottiana). The decomposition rates, lignin, cellulose, hemicellulose and nitrogen degradation were faster in legume than non-legume in Lowland forest. On the other hand, there was no difference in decomposition rates between M. schottiana and I. lanceifolia in Montane forest. But, comparing M. schottiana specie, a common non-legume in the two altitudes, this specie decomposed faster in Lowland than Montane forest. In Lowland forest, not only higher temperatures, but also the different chemical characteristics, such as high nitrogen content and low C:N ratio in the legume litter could accelerate the decomposition processes in this forest, in addition, lower polyphenols concentration in M. schottiana in Lowland compared to Montane forest can also favored the high decay rates in Lowland forest. Therefore, the litter chemical characteristics also appear to regulate the decomposition rates

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study was to determine the plant alloctonous material input and its processing by shredders in the Caranguejo Creek, a first order Neotropical stream. In order to do so, three experiments were performed. To verify the plant alloctonous material input, five suspended and ten lateral leaf-collectors were installed in the study area. Two samplings were made each season of the year, with a total of approximately 15 sampling days for each season. Input was higher in the suspended collectors than in the lateral ones. There was no difference in input amongst the seasons, and the annual input was of 1.254 g.m-2.year-1. Leaves were the most abundant material, comprising 61,38% of the sample, followed by twigs (29,15%) and others (9,46%). To evaluate the role of decapod crustaceans in shredding, channels containing litter bags of Ficus luschnathiana leaves were placed within the creek. Two types of channels were used, one allowing the decapods to access the leaves, and the other preventing it. Both types had the litter bags accessible to other invertebrates that integrated the stream community. The leave s decomposition rate was faster in the presence of decapods, indicating their potential as shredders. Besides accelerating the decomposition rates, the presence of decapods altered the community composition and density of individuals associated with the litter bags. The density of the macroinvertebrates was higher in the absence of decapods. The most representative functional feeding group were the collectors. The typical shredders were represented by the families Gripopterygidae e Sericostomatidae, comprising 4% of the total. The decapods species found in the study area are the anomuran Aegla longirostri, in higher densities, and the crayfish Parastacus pilimanus. In order to verify the percentage of alloctonous leaves that A. longirostri is capable of processing, an experiment was conducted in the laboratory. Leaves of different species, collected in the creek, were offered to the individuals, and its consume recorded. There was no difference in leaf consumption between adults (males and females), but there was a difference among these and the juveniles. Adults consumed a mean of 0,0175 (± 0,005)g of leaves per day, and the juveniles consumed 0,010 (± 0,002)g/day. With the data concerning leaf input, the daily leaf consumption rates and the information on the density of the aeglids, at the study site, it was possible to estimate that this population of A. longirostri is able to process approximately 6,14% of the leaves that fall in the creek. These results show that Caranguejo Creek is a location that receives many types of vegetal organic matter, through input from the riparian vegetation, that will be consumed by the aquatic community. Besides, the area possesses low abundance of insect shredders, and therefore the decapod crustaceans present a highlighted importance as shredders. / Este estudo tem como objetivo determinar o aporte de material alóctone vegetal e o seu processamento por fragmentadores na Sanga do Caranguejo, um riacho neotropical de primeira ordem. Para tanto foram realizados três experimentos. Para verificar o aporte de material alóctone vegetal foram instalados na área de estudo 5 coletores suspensos e 10 coletores laterais. Foram realizadas duas coletas por estação do ano, totalizando aproximadamente 15 dias por estação. O aporte foi maior nos coletores suspensos do que nos coletores laterais. Não houve diferença no aporte entre as estações do ano e o aporte anual foi de 1,254 g.m-2.ano-1. As folhas foram o material mais abundante com cerca de 61,38%, seguido pelos galhos (29,15%) e outros (9,46%). Para analisar a importância de crustáceos decápodos na fragmentação, foram colocados no riacho canais com sacos de detritos de Ficus luschnathiana. Havia dois tipos de canais, um que permitia o acesso dos decápodos às folhas e outro que restringia o seu acesso, mas ambos permitiam o acesso de outros macroinvertebrados presentes na comunidade aquática do local. A taxa de decomposição das folhas foi mais rápida na presença dos decápodos, indicando o potencial deste grupo como fragmentador. Além de acelerar a taxa de decomposição a presença dos decápodos alterou a comunidade e a densidade de indivíduos associados aos sacos de detritos. A densidade de indivíduos foi maior na ausência dos decápodos. O grupo trófico funcional mais representativo foi o dos coletores, os tipicamente fragmentadores foram representados pelas famílias Gripopterygidae e Sericostomatidae, representando 4% do total. As espécies de decápodos encontrados na área de estudo são o anomuro Aegla longirostri, em maior densidade, e o lagostim Parastacus pilimanus. Para verificar a porcentagem de folhas alóctone que A. longirostri é capaz de processar foi realizado um experimento em laboratório. Folhas de diferentes espécies, coletadas no riacho, foram oferecidas aos indivíduos e o seu consumo foi registrado. Não houve diferença no consumo de folhas entre os adultos (machos e fêmeas), mas houve diferença entre estes e os juvenis. Os adultos consumiram em média 0,0175 (± 0,005) gramas de folhas por dia e os juvenis 0,010 (± 0,002). A partir dos dados de aporte de folhas, o consumo diário de folhas e os dados sobre a densidade de eglídeos no local de estudo, foi possível estimar que a população de A. longirostri pode processar aproximadamente 6,14% das folhas que caem no riacho. Esses resultados indicam que a Sanga do Caranguejo é um local que, através da vegetação ripária, recebe diferentes materiais vegetais que serão utilizados pela comunidade aquática, além disso, possui reduzida abundância de insetos fragmentadores e tem como principais fragmentadores os crustáceos decápodos.

What will happen to ecosystems if species continue to go extinct at the high rates seen today? Although ecosystems are often threatened by a myriad of physical or chemical stressors, recent evidence has suggested that the loss of species may have impacts on the functions and services of ecosystems that equal or exceed other major environmental disturbances. The underlying causes that link species diversity to ecosystem functioning include species niche complementarity, facilitative interactions, or selection effects, which cause process rates to be enhanced in more diverse communities. Interference competition, antagonistic interactions, or negative selection effects may otherwise reduce the efficiency or resource processing in diverse communities. While several of these mechanisms have been investigated in controlled experiments, there is an urgent need to understand how species diversity affects ecosystem functioning in nature, where variability of both biotic and abiotic factors is usually high. Species functional traits provide an important conceptual link between the effects of disturbances on community composition and diversity, and their ultimate outcomes for ecosystem functioning. Within this framework, I investigated relationships between the decomposition of leaf litter, a fundamental ecosystem process in stream ecosystems, and the composition and diversity of functional traits within the detritivore feeding guild. These include traits related to species habitat and resource preferences, phenology, and size. I focused on disentangling the biotic and abiotic drivers, including functional diversity, regulating ecosystem functioning in streams in a series of field experiments that captured real-world environmental gradients. Leaf decomposition rates were assessed using litter-bags of 0.5 and 10 mm opening size which allow the quantification of microbial and invertebrate + microbial contributions, respectively, to litter decomposition. I also used PVC chambers where leaf litter and a fixed number of invertebrate detritivores were enclosed in the field for a set time-period. The chemical characterisation of stream detritivores and leaf litter, by means of their nitrogen, phosphorus, and carbon concentration, was used to investigate how stoichiometric imbalance between detritivores and leaf litter may affect consumer growth and resource consumption. I found that the diversity and composition of functional traits within the stream detritivore feeding guild sometimes had effects on ecosystem functioning as strong as those of other major biotic factors (e.g. detritivore density and biomass), and abiotic factors (e.g. habitat complexity and agricultural stressors). However, the occurrence of diversity-functioning relationships was patchy in space and time, highlighting ongoing challenges in predicting the role of diversity a priori. The stoichiometric imbalance between consumers and resource was also identified as an important driver of functioning, affecting consumer growth rates, but not leaf decomposition rates. Overall, these results shed light on the understanding of species functional diversity effect on ecosystems, and indicate that the shifts in the functional diversity and composition of consumer guilds can have important outcomes for the functioning of stream ecosystems.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-05-04T14:32:46Z No. of bitstreams: 1 marcospereiralopes.pdf: 2209315 bytes, checksum: 7fb3d297f8d26fb98f07a65d24dfd96f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T13:31:19Z (GMT) No. of bitstreams: 1 marcospereiralopes.pdf: 2209315 bytes, checksum: 7fb3d297f8d26fb98f07a65d24dfd96f (MD5) / Made available in DSpace on 2017-05-17T13:31:19Z (GMT). No. of bitstreams: 1 marcospereiralopes.pdf: 2209315 bytes, checksum: 7fb3d297f8d26fb98f07a65d24dfd96f (MD5) Previous issue date: 2014-02-28 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Na região tropical são escassos os estudos que exploram o uso do processo de decomposição foliar como ferramenta funcional para avaliar os efeitos das perturbações antrópicas sobre os ecossistemas aquáticos. Nosso objetivo foi avaliar os efeitos dos impactos antrópicos sobre a taxa de decomposição de Picramnia sellowii em riachos no Sudeste do Brasil. O experimento foi realizado durante 60 dias em três riachos referências e três impactados por poluição orgânica e sem cobertura vegetal. Em cada riacho foram incubados três sacos contendo 3 ± 0,05 g de folhas secas de P. sellowii. Os riachos referência apresentaram maiores concentrações de oxigênio dissolvido e menores valores de nutrientes, turbidez, condutividade elétrica, TIA (área total impermeável) e temperatura. O coeficiente de decomposição (k) diferiu entre os riachos referência (k = 0,014 ± 0,003 d-1) e os impactados (k = 0,005 ± 0,001 d-1). Nas folhas incubadas nos riachos referência foi observada maior biomassa de fungos e abundância de invertebrados, assim como a presença de fragmentadores, estando o k relacionado com a biomassa destes organismos. A decomposição se mostrou sensível para avaliar impactos antrópicos nos ecossistemas aquáticos uma vez que foram observadas nítidas diferenças entre a perda de massa foliar nos riachos referências e impactados. Estes resultados reforçam o efeito negativo da urbanização sobre a decomposição e biomassa de fungos e fragmnetadores. No segundo experimento foram realizadas retiradas após 7, 15, 30, 60, 90 e 120 dias, em três remansos e três corredeiras apenas nos riachos referências. Os principais resultados foram: no final do experimento restaram 16,63 % (remansos) e 10,30 % (corredeiras) de massa seca, que diferiu apenas entre os dias do experimento e não entre os mesohabitats e, foi influenciada pela biomassa de fungos; houve aumento na biomassa destes microorganismos no dia 90, diferindo apenas entre os dias do experimento e sendo influenciada pela temperatura e O2; a abundância de invertebrados foi maior em corredeiras e no dia 30, apresentando diferença entre mesohabitats e entre os dias, e sendo influenciada pela temperatura, O2 e velocidade; maior riqueza foi registrada em remansos e no dia 60; a família Chironomidae foi a mais abundante durante todo o experimento nos dois mesohabitats; a abundância e biomassa de fragmentadores foram baixas; o escalonamento multidimensional não métrico mostrou a separação dos mesohabitats e períodos inicial e final da decomposição. Através do segundo experimento foi possível observar que a perda de massa nos ecossistemas lóticos de baixa ordem é mais influenciada pela biomassa de fungos que pela biomassa de fragmentadores e pela velocidade da água. Adicionalmente, observamos que diferenças na abundância, riqueza e composição de invertebados são influenciadas por diferenças entre mesohabitats e pela sucessão ao longo da decomposição. Esses resultados contribuem para reforçar a importância do material vegetal de origem terrestre como fonte de energia para os invertebrados em riachos, e a necessidade de preservação da vegetação ripária. / There are few studies in tropical regions exploring the use of leaf breakdown process as a functional tool to assess anthropic disturbance on aquatic ecosystems. We assessed the effects of water pollution due to human activities on the leaf breakdown rate of Picramnia sellowii in streams of the southeastern Brazil. The experiment was carried out for 60 days in three reference streams and three streams impaired by organic pollution and absente of riparian vegetation. Three litter bags were incubated in each stream containing 3 ± 0.05 g of P. sellowii leaves. The reference streams presented higher values of dissolved oxygen and lower values of nutrients, turbidity, electrical conductivity, total impermeable area and water temperature. The leaf breakdown rate (k) differed significantly between the reference (k = 0.014 ± 0.003 d-1) and impaired streams (k = 0.005 ± 0.001 d-1). The leaves incubated in the reference streams contained greater fungal biomass (measured as ergosterol concentration) and abundance of invertebrates, as well as greater presence of shredders, with k values being related to the biomass of these organisms. Overall, there were clear differences between the leaf mass loss in the reference and impaired streams. These results reinforce the negative effect of urbanization on leaf breakdown and fungal and shredder biomass. In the second experiment were performed withdrawn after 7, 15, 30, 60, 90 and 120 days, in three backwaters and three rapids only in streams references. The main results were: at the end of the experiment remained 16.63% (backwaters) and 10.30% (rapids) of dry mass, which differed only between days of the experiment and not between mesohabitats and was influenced by fungal biomass; there was an increase in biomass of these microorganisms on day 90, differing only from the days of the experiment and being influenced by temperature and O2; the abundance of invertebrates was higher in rapids and on the 30 th, presenting difference between mesohabitats and between days, and being influenced by temperature, O2 and speed; greater richness was recorded in backwaters and day 60; the family Chironomidae was the most abundant throughout the experiment in both mesohabitats; the abundance and biomass of shredders were low; non-metric multidimensional scaling showed the separation of mesohabitats and initial and final periods of decomposition. Through the second experiment it was observed that the mass loss in the low-order stream ecosystems is more influenced by the biomass of fungi that the biomass of shredders and the velocity of the water. Additionally, we found that differences in the abundance, richness and composition invertebados are influenced by differences between mesohabitats and the succession in the decomposition. These results help to reinforce the importance of plant material of terrestrial origin as an energy source for invertebrates in streams, and the need for preservation of riparian vegetation.

Abstract Streams and rivers have been extensively altered by humans. Channelization and land use have changed stream habitats and water quality with adverse effects on biota and ecosystem functions. Impacted streams have been targets for restoration, but there is considerable lack of understanding how streams should be restored in an ecologically effective way. In this doctoral thesis, I studied the impacts of channelization (for timber floating) and agricultural diffuse pollution on stream biota. I also studied the effectiveness of restorations of forestry impacted streams stressed by excessive sand sedimentation from catchment drainage. Finally, I also studied the effects of mosses, fine sediment and enhanced dispersal on stream macroinvertebrate communities and ecosystem functions. I found that channelization did not have effect on diatom, macrophyte, macroinvertebrate and fish assemblages, whereas diffuse pollution had strong effects, with no interactions between the two stressors. I showed that excessive sedimentation from forest drainage was harmful for stream biota but had no effect on leaf decomposition and algal accrual rate. Restoration with boulders reduced sand cover and was more beneficial for in-stream biodiversity, whereas restoration with wood tended to increase hydrological retention of stream channels, thereby altering riparian plant assemblages toward more natural composition. In a mesocosm experiment, I found mosses to have a strong impact on macroinvertebrate communities and ecosystem functions. Mosses increased organic matter retention and reduced algal accrual rate and leaf decomposition. The effect of mosses on macroinvertebrates was stronger than that of sand sedimentation, and mosses mitigated some of the negative effects of sand. Extensive dispersal had a distinct imprint on invertebrate community composition but did not blur the effect of mosses and sand on communities, suggesting strong local-scale environmental control of composition. My thesis emphasizes that priority in stream restoration should be in the mitigation of diffuse pollution rather than restoration of channel morphology, especially in streams where channel alteration has been fairly modest, as in the case of timber floating. Addition of both boulders and large wood likely yields the best biodiversity response in the restoration of forestry impacted streams. Mosses are a key component of boreal lotic ecosystems; therefore, the recovery of mosses may be a prerequisite for the full recovery of biodiversity and ecosystem integrity of boreal streams. / Tiivistelmä Ihmisen toiminta on laajasti muokannut virtavesiä. Uomien kanavointi ja maankäyttö ovat muuttaneet virtavesien elinympäristöjä ja veden laatua, millä on ollut haitallisia vaikutuksia virtavesien luonnon monimuotoisuuteen ja ekosysteemin toimintaan. Huonokuntoisia virtavesiä on kunnostettu paljon, mutta ymmärrys siitä, kuinka virtavesiä tulisi kunnostaa parhaan ekologisen lopputuloksen saavuttamiseksi, on edelleen vajaata. Tutkin tässä väitöskirjassa uittoperkausten ja maatalouden hajakuormituksen merkitystä ja yhteisvaikutusta virtavesien eliöyhteisöihin. Tutkin myös kunnostusten vaikutusta hiekasta kärsivissä metsätalouden muokkaamissa puroissa, sekä vesisammalten, hiekan ja eliöiden levittäytymisen merkitystä purojen pohjaeläinyhteisöjen ja ekosysteemin toimintojen muovautumisessa. Havaitsin, että uoman perkauksilla ei ollut vaikutusta virtavesien eliöyhteisöihin, mutta hajakuormituksen vaikutus oli voimakas. Perkauksella ja hajakuormituksella ei ollut yhteisvaikutuksia eliöyhteisöihin. Osoitin, että metsäojituksista aiheutuva ylimääräinen hiekan sedimentaatio on haitallista virtavesien eliöille, mutta sillä ei ollut vaikutusta lehtikarikkeen hajotukseen tai päällyslevien tuotantoon. Kunnostukset joissa käytettiin kiveä vähensivät hiekan peittävyyttä ja olivat hyödyllisempiä uoman eliöstölle kuin kunnostukset, joissa tehtiin puurakennelmia. Puukunnostukset kuitenkin lisäsivät uoman vedenpidätyskykyä ja siten muokkasivat rantavyöhykkeen kasvillisuutta luonnontilaisemmaksi. Havaitsin, että vesisammalilla on voimakas vaikutus pohjaeläinyhteisöjen koostumukseen. Sammalet vaikuttivat ekosysteemin toimintoihin lisäämällä eloperäisen aineksen pidättymistä ja vähentämällä lehtikarikkeen hajotusta ja päällyslevien tuotantoa. Sammalten vaikutus pohjaeläimiin oli voimakkaampi kuin hiekan, ja sammalet kykenivät jopa lieventämään joitakin hiekan negatiivisia vaikutuksia. Eliöiden levittäytymisellä oli selvä vaikutus yhteisöjen koostumukseen, mutta se ei hävittänyt hiekan ja sammalen vaikutusta, mikä viittaa korkeaan ympäristötekijöiden merkitykseen yhteisöjen rakentumisessa. Tutkielmani korostaa, että maatalousjokien tilan parantamisessa hajakuormituksen hallinta tulisi olla ensisijainen kunnostustavoite uoman rakenteen kunnostamisen sijaan. Metsätalouden vaikutuksista kärsivissä puroissa kivi- ja puumateriaalin käyttö samanaikaisesti tuottaa luultavimmin laajimman vaikutuksen purojen monimuotoisuuteen. Sammalilla on merkittävä vaikutus muiden eliöiden yhteisökoostumukseen ja ekosysteemin toimintoihin, joten sammalten palautuminen on tärkeä kunnostustavoite virtavesissä, joissa on luonnostaan paljon sammalkasvustoa.