No description available.

No description available.

Abstract Maintaining connectivity in boreal streams by rehabilitation procedures is a challenging task that requires ecological understanding based on empirical research. In this thesis, I examined the effects of stream rehabilitation on densities and growth of brown trout (Salmo trutta L.), as well as on benthic biodiversity. As streams are known to be closely connected to their watersheds, I also examined the effects of watershed drainage activities on stream organisms. The results of this thesis have implications for enhancing salmonid populations, as well for maintaining stream biodiversity. First, regional climatic variability was shown to override local impacts of watershed management on stream biota. This highlights the importance of placing results from local studies in a regional context. Second, increased sedimentation that typically follows anthropogenic actions in the watershed did not only cause direct mortality on the early life stages of brown trout, but also forced them to emerge earlier from gravel and constrained their development. Thus, sedimentation may have far-reaching fitness consequences on juvenile salmonids. Third, while instream rehabilitation did enhance habitat diversity for salmonid fish, there were only marginal effects on juvenile fish and benthic biodiversity. Therefore, the factors limiting stream biota, and obscuring positive effects of rehabilitation, are to be found elsewhere. For this purpose, my thesis offers at least three potential, not mutually exclusive explanations: (i) land use changes have altered watersheds and this can be seen as decreased stream biodiversity that cannot be corrected through local-scale restoration efforts; (ii) a habitat-forming organism group, stream bryophytes, is dispersal limited, slowing down any positive responses to restoration by fish or invertebrates that depend strongly on bryophytes; and (iii) changes to stream habitat heterogeneity caused by channelization for timber floating were rather modest to start with, and therefore any effects of stream habitat rehabilitation on stream biota are likely to be subtle. Based on these findings, I suggest that future restoration efforts should be prioritized according to a comprehensive watershed assessment. Also, monitoring of projects should be more rigorous and preferably multidisciplinary, documenting the ecological as well as hydrological and socioeconomic outcomes of rehabilitation projects.

It is important for humans to understand how ecosystems work because we depend on them for a variety of products and services. For example, rivers and streams provide fisheries, improved water quality, and recreational opportunities to many individuals. In rivers, interactions among fishes, other stream plants and animals, and the physical river environment can influence continued provision of these valuable services. However, the role played by many freshwater fishes in the provision of these services remains unknown. Additionally, it is important to identify different factors that affect the outcome of interactions involving riverine fishes. To address these issues, I evaluated how fishes influence different properties of rivers and streams, using a combined approach that summarized previous studies of fish effects on trophic structure and organic matter processing and incorporated field work in natural systems. Overall, my work demonstrated that fishes can play important roles in rivers and streams. In particular, fish spawning migrations from lakes to streams can introduce nutrients to streams. Compared with other nutrient sources for streams, nutrients delivered by fish migrations can be substantial, and they may be used by other plants and animals in the stream to increase productivity. Beyond nutrient introduction, the physical disturbance of river sediments caused by the spawning activity of large migratory fishes can influence the availability of food resources for other stream animals. Additionally, my summary of previous fish studies indicated the consistent influence of fishes on nutrient dynamics and other stream organisms. While the role of riverine fishes varies, natural resource managers and researchers should focus on understanding how these widespread organisms influence valuable ecosystem services derived from freshwater resources.

Connectivity in ecological systems is a broad concept that embodies the transmission of ecosystem components throughout landscapes at multiple spatial and temporal scales. Of relevance to the present study are the connections (or lack thereof) among local populations of stream fauna - population connectivity in lotic systems. Dispersal, recolonisation and migration are the demographic forms of population connectivity, and gene flow is the genetic aspect of population connectivity. Both forms of population connectivity have underpinned some of the classic theories and hypotheses in stream ecology, and have implications for pure and applied stream ecology, including ecosystem restoration. Conceptual models in ecology can facilitate understanding and predictability of the ecosystem processes they represent, and have potential applicability as management tools or 'rules of thumb' in conservation and restoration programs. Various theoretical models describe potential patterns of connectivity among local populations and in this thesis these models were used to evaluate population connectivity in a freshwater fish (southern pygmy perch, Nannoperca australis) and two reproductively isolated genetic lineages of freshwater shrimp (Paratya spp.) in small, geomorphically degraded streams in south eastern Australia. These streams (the Granite Creeks) have been the focus of a recent habitat restoration trial and several studies have examined fish and macroinvertebrate community responses to the experiment. It was the purpose of this study to contribute information about population connectivity in the selected species to complement these community ecology studies. Population connectivity was examined in these species using molecular data (mitochondrial and nuclear genetic data) and natural abundance isotopic signatures of nitrogen and carbon. At the landscape scale, results showed that populations of N. australis and the P. australiensis lineages were isolated among the streams and among sites within streams, and that there was no consistent pattern of isolation-by-distance in genetic data for any species. Thus, classic models of population connectivity, such as the Island Model and Stepping-Stone Model, were not supported by this study. Results indicated that population models that incorporated more complex aspects of stream structure may be more appropriate than these classic models for approximating observed patterns of population connectivity in lotic systems. The Stream Hierarchy Model (SHM) predicts that the hierarchical aspect of stream structure (i.e. stream confluences) have a dominant role in shaping patterns of population connectivity in lotic fauna, whereby populations among streams are more isolated than those within them. Although stream confluences were found to have an important role in population subdivision for the species examined in this study, the expectations of the SHM were met for only N. australis. For the P. australiensis lineages, the influence of topography (i.e. the longitudinal aspect of stream structure) was just as important as stream confluences in isolating local populations. Large-scale determinants of population isolation were thus found to be associated with both the hierarchical and longitudinal aspects of stream structure, and were not well represented by any single theoretical model of population connectivity. At within-stream scales, upland populations tended to be extremely isolated from other populations and had temporally stable genetic signatures. In contrast, lowland populations were connected to other lowland populations within the same stream to a greater degree, although the connections were patchy and a slight signature of temporal instability in the genetic data was evident for one of the P. australiensis lineages. Thus, metapopulation or patchy population models were found to represent connections among lowland populations within the same stream, although they were not appropriate for describing connectivity among upland populations. This finding highlights the importance of the longitudinal aspect of stream structure in shaping ecological patterns in lotic systems, and demonstrates that local patterns of population connectivity can vary over relatively small spatial scales. Overall, the results illustrate that both hierarchical and longitudinal aspects of stream structure can have important roles in isolating populations of stream fauna. They therefore also represent constraints for the ability of aquatic fauna to colonise restored habitat in streams. The corollary of this, however, is that such isolated populations of stream fauna represent appropriate population units at which to target habitat restoration. The hierarchical and longitudinal aspects of stream structure may thus represent 'rules of thumb' or 'landscape filters' that stream restoration ecologists could use to predict likely isolated populations of lotic fauna across the landscape. Such a 'rule of thumb' might be the inclusion of multiple isolated population units in restoration programs, as this strategy is likely to generate the greatest biological response to the restoration at the landscape scale, particularly with respect to intra-specific genetic diversity captured by restoration. At small spatial scales, such as for a single stream or tributary, the longitudinal aspect of stream structure can be an important factor to consider when designing stream habitat restoration programs. In this study, lowland sites were unstable and there were patchy connections among local lowland populations within the same stream, whereas upland populations were isolated at this scale. In contrast, other studies have found that upstream populations of some species can be connected in a patchy fashion in other systems. For such unstable sections of stream, where there are patchy patterns of local population connectivity, the inclusion of multiple restored patches, especially refugial habitat, is likely to produce the greatest biotic response at the patch scale, particularly with respect to demographic responses (such as local colonisation). Multiple restored refugial patches will enable species to persist throughout the stream section during adverse environmental conditions, will allow for variation in local movement patterns and distances between species and between years with contrasting environment conditions (e.g. stream flow), and may harbour different species assemblages and intraspecific genotypes due to stochastic processes (i.e. have functional heterogeneity). The hierarchical and longitudinal aspects of stream structure are thus important determinants of population connectivity at both large and small spatial scales, and have implications for how stream biota will respond to restoration at patch and landscape scales.

The eastern Nearctic fauna of Blepharicera Macquart (Diptera: Blephariceridae) is revised to include twenty-three species, six of which are new to science. Descriptions of the larvae, pupae, and adults of B. amnicula n. sp., B. conifera n. sp., B. crista n. sp., B. enoristera n. sp., B. hillabee n. sp., and B. opistera n. sp. are presented. Keys to instar IV larvae, pupae, and adults of all eastern Blepharicera (except B. caudata Courtney) are provided. Phylogenetic studies were conducted to determine the relationships between eastern and western Nearctic Blepharicera and among species within these groups. Larvae, pupae, and adults were available for all known Nearctic species except B. caudata and B. micheneri Alexander. Molecular data acquired from two genes and morphological data for 44 characters were used to test previous phylogenetic hypotheses on the historical relationships and biogeography of Nearctic Blepharicera. Analyses using maximum parsimony, maximum likelihood, and Bayesian inference were conducted. Resulting phylogenies support monophyly of the B. tenuipes and B. micheneri groups and suggest that multiple species complexes may exist within the B. tenuipes group.

Criteria used to characterize lotic salmonid habitat are often based on observed correlations between physical habitat characteristics and salmonid abundances. A focus on physical habitat features ignores other habitat components, such as an adequate supply of food that set the physiological limitations on salmonid growth and survival. This study outlines the development of a habitat assessment approach that focuses on how invertebrate food availability interacts with stream temperatures to determine salmonid growth potentials. Abundances of benthic and drifting invertebrate communities, stream temperatures, and juvenile steelhead trout (Onchorhynchus mykiss gairdneri) summer growth rates and abundances were measured within 10 distinct stream segments in central Oregon. Stream temperatures and growth rates were used as inputs for bioenergetics model simulations to produce estimates of O. mykiss summer consumption rates. Measures of invertebrates providing the best description of food availability were chosen based on their ability to explain observed variation in salmonid consumption. Much of the variation in O. mykiss consumption estimates was explained by measurements of total drift biomass along a type II predator response curve. A random effects analysis of variance (ANOVA) was used to partition variation in invertebrate abundances across spatial and temporal scales. Quantification of variation at multiple scales allowed identification of a relevant spatial scale at which to assess macroinvertebrates relevant to salmonid populations, and compare the precision associated with measures of benthic and drifting invertebrate abundances. Results suggested that spatial variation in drifting and benthic invertebrate abundances are greatest at the scale of streams. Total drift biomass and total benthic biomass were more precise at the stream and stream reach scale than drift and benthic density. The information provided by this study will be used to guide the development of sampling approaches that describe invertebrates in a manner more directly related to salmonid production.

No description available.

O presente trabalho teve como objetivo geral estudar o ciclo de vida, a produtividade secundária, a distribuição, a alimentação e o crescimento de Massartela brieni em riachos do Parque Estadual Intervales, Estado de São Paulo. O material analisado foi coletado em seis pontos de coleta, um no córrego Roda d´Água, um no córrego Mirante, um no córrego Bocaina, dois no córrego Água Comprida e um no córrego Lajeado. Em todos os pontos, substrato rochoso foi coletado com um amostrador de Surber com 0,250 mm de malha, em cada amostragem foram feitas 10 subamostras aleatórias perfazendo o total de 1m2. No Córrego Bocaina, folhiço em corredeira e em remanso também foram amostrados com rede D (10 pacotes de folhiço com 0,01 m2 cada). As coletas foram feitas entre Setembro/1999 e Setembro/2001. A análise dos histogramas referentes ao número de indivíduos em diferentes classes de tamanho foi inconclusiva quanto ao voltinismo da espécie estudada. A produtividade secundária anual de Massartella brieni foi 4802,79 mg.m-2ano-1 para um CPI de 120 dias, 3842,24 mg.m-2ano-1 para um CPI de 150 dias e 3201,86 mg.m-2ano-1 para um CPI de 180 dias. Os resultados indicam que M. brieni ocorreu preferencialmente em locais com menor velocidade de água associados com acúmulo de folhiço. Não houve uma relação linear negativa entre a vazão, a precipitação (mês anterior) e a densidade de M. brieni no córrego Mirante. No entanto, foi possível observar que meses com maior vazão ou precipitação (mês anterior) nunca apresentaram altas densidades. Na maior parte dos meses, os períodos com baixas densidades também foram os que apresentaram menor biomassa, exceto para os meses de Março a Maio de 2000 (meses que ocorreram indivíduos de maior porte). Durante o crescimento a maior parte das estruturas da cabeça tiveram alometria negativa, enquanto que as do abdômen e a maior parte das do tórax tiveram alometria positiva. A mudança de forma da maxila (Deformação Relativa I) teve uma leve relação significativa com o crescimento de M. brieni. / The present work had as general aim to study the life cycle, secondary production, distribution, feeding habits and growth of Massartela brieni from streams of the Parque Estadual Intervales, State of São Paulo. The analyzed material was collected in six collection stations, one in Roda d´Água stream, one in Mirante stream, one in Bocaina stream, two in Água Comprida stream and one in Lajeado stream. In all stations, rocky substratum was collected with Surber sampler with 0,250 mm of mesh, in each sampling 10 sampling units were taken randomily, totalling 1m2. In the Bocaina stream, litter in riffles and in pools were also sampled with D net (10 litter patches with 0,01 m2 each). The collections were carried out between September/1999 and September/2001. The analysis of size frequency histograms representing the number of individuals in different classes of size was inconclusive in relation to voltinism of the studied species. The annual secondary production of Massartella brieni was 4802,79 mg.m-2yr-1 for a CPI of 120 days, 3842,24 mg.m-2yr-1 for a CPI of 150 days and 3201,86 mg.m-2yr-1 for a CPI of 180 days. The results indicate that M. brieni occurred preferentialy in sites with lesser water speed and with litter accumulations. There was not a negative linear relation between the discharge and the precipitation (previous month) with density of M. brieni in Mirante stream. However, it was possible to observe that months with higher discharge or precipitation (previous month) did not present high densities. For the most part of the months, the periods with low densities had lesser biomass, except for the months from March to May of 2000 (months in which individuals of larger size occurred). During the growth, the most of the structures of the head had negative allometry, whereas of the abdomen and most measurements of the thorax had positive allometry. The change of shape of the maxillae (Relative Warps I) had a slight significant relationship with the growth of M. brieni.

A presente dissertação de mestrado resume-se a um estudo da diversidade de Leptoceridae e Hydropsychidae (Insecta, Trichoptera) do Parque Estadual Intervales, Estado de São Paulo, objetivando diminuir as lacunas distribucionais das espécies e facilitar o acesso de tais informações a outros pesquisadores, fornecendo subsídios taxonômicos para futuros trabalhos ecológicos ou de cunho conservacionista, aumentando assim, o conhecimento sobre as famílias Leptoceridae e Hydropsychidae e, consequentemente, sobre a ordem Trichoptera. A coleta foi realizada em dez riachos entre os meses de julho e agosto de 2010. O material coletado foi triado, preparado e identificado até o nível taxonômico de espécie. Análises quantitativas e testes estatísticos foram realizados para a determinação da riqueza e a abundância das duas famílias, além de, a partir das informações bióticas e abióticas nos diferentes riachos e das localidades de coleta, tentar inferir quais fatores ambientais são determinantes na distribuição faunística de tricópteros entre os diferentes riachos. Foi criada também uma checklist para as espécies de Leptoceridae e Hydropsychidae que ocorrem no Parque Estadual Intervales. Com a análise do material coletado, foi possível o reconhecimento de novas espécies e novos registros de espécies para o Estado de São Paulo. As novas espécies foram descritas ou encaminhadas para tricopterólogos especialistas, aumentando assim o conhecimento taxonômico do grupo em questão e contribuindo diretamente para a diminuição entre a diferença no número de espécies descritas na literatura e as estimativas do número de espécies existentes. / This dissertation summarizes a study of the diversity of Leptoceridae and Hydropsychidae (Insecta, Trichoptera) in Parque Estadual Intervales streams, State of São Paulo, aiming to reduce the distributional gaps of species and facilitate the access of such information to other researchers, providing subsidies for future taxonomic or ecological studies and for nature conservation, and increasing the knowledge about the families Leptoceridae and Hydropsychidae and, consequently, of the order Trichoptera. Data were obtained between July and August 2010, when ten streams were sampled. The collected material was sorted, prepared and identified to the taxonomic level of species. Quantitative analysis and statistical tests were performed to determine the richness and abundance of the two families. Biotic and abiotic information from different streams and sampling localities were also analysed, trying to infer which environmental factors are determinant in the distribution of the fauna of caddisflies. A checklist of the species of Leptoceridae and Hydropsychidae from Parque Estadual Intervales is also presented. The analysis of the collected material showed the presence of new species; these were described or sent to experts, thus increasing the taxonomic knowledge of the Trichoptera and contributing to decrease the difference between the number of described species and estimates of the number of existing species.