Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2016-08-09T14:53:03Z No. of bitstreams: 1 beatrizfigueiraujojabourvescovirosa.pdf: 1816042 bytes, checksum: 143468b9f90a82552f0e11a1f14d4045 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-08-09T15:16:03Z (GMT) No. of bitstreams: 1 beatrizfigueiraujojabourvescovirosa.pdf: 1816042 bytes, checksum: 143468b9f90a82552f0e11a1f14d4045 (MD5) / Made available in DSpace on 2016-08-09T15:16:03Z (GMT). No. of bitstreams: 1 beatrizfigueiraujojabourvescovirosa.pdf: 1816042 bytes, checksum: 143468b9f90a82552f0e11a1f14d4045 (MD5) Previous issue date: 2015-08-14 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O uso dos organismos nas avaliações dos ambientes aquáticos possibilita o entendimento da estrutura e dos processos funcionais destes ecossistemas. A partir das métricas da assembleia de Chironomidae (Diptera) de mesohabitats de remansos e corredeiras, este estudo possibilitou identificar o estado de conservação de nove riachos de baixa ordem pertencentes à sub-bacia do Ribeirão Marmelos, localizado no Município de Juiz de Fora, MG. No primeiro capítulo, o experimento 1 investigou a sucessão de Chironomidae em sacos de folhas de Picramnia sellowii, incubados em remansos e corredeiras em três riachos florestados durante 120 dias. As mudanças na composição e estrutura da fauna foram atribuídas principalmente à perda de massa foliar e à heterogeneidade física do detrito, especialmente após a decomposição atingir 50% (60 dias), quando houve a maior riqueza de táxons. Aos 30 dias, a dominância de larvas de Stenochironomus possivelmente contribuiu para maior fragmentação física do detrito. A ausência de relação entre Chironomidae não minadores e a biomassa de fungos indicou que muitas larvas usaram as folhas apenas como substrato. Entre os mesohabitats houve fraca variação na composição da fauna. O experimento 2, que comparou a fauna de Chironomidae dos sacos de folhas aos 60 dias de decomposição entre os riachos florestados e impactados pela poluição orgânica, detectou nítida diferença na composição de táxons entre os ambientes. As métricas de Chironomidae tiveram forte relação com as variáveis ambientais que distinguiram os riachos preservados e impactados, sugerindo-se o uso desta metodologia para avaliação das condições ambientais de riachos. O segundo capítulo investigou se métricas da assembleia de Chironomidae iriam diferir entre remansos e corredeiras em resposta aos diferentes usos da terra (floresta, pastagem e urbano) em riachos de baixa ordem, no período seco e chuvoso. Foi constatado que a composição de táxons de ambos os mesohabitats e períodos foi a métrica mais sensível ao uso da terra, o que sugere que o uso desta métrica de um ou outro mesohabitat e período estacional para o biomonitoramento, possibilita a obtenção de resultados menos influenciados pela variabilidade natural do ambiente e a diminuição do tempo para o processamento das amostras. No capítulo três foi analisada a concordância taxonômica de grupos bentônicos identificados em diferentes níveis taxonômicos. Gêneros de Chironomidae e gêneros de Ephemeroptera, Plecoptera e Trichoptera (EPT) foram concordantes no período de seca e chuva. O mesmo foi constatado para gêneros de Chironomidae e espécies de Oligochaeta. Famílias de macroinvertebrados foram concordantes com gêneros de Chironomidae e gêneros de EPT somente no período seco. Respostas similares às variáveis ambientais foram responsáveis pela concordância entre os grupos, enquanto a proximidade dos riachos resultou na ausência de influencia das variáveis espaciais. Constatou-se ainda, a efetividade da resolução numérica de gêneros de Chironomidae e espécies de Oligochaeta em ambos os períodos do estudo. A porcentagem de perda de informação, (>15%) indicou cautela ao se utilizar dados de presença/ausência destes grupos, sugerindo-se sua utilização apenas para avaliações rápidas em ambientes com diferenças marcadas nas suas condições de conservação. / The use of organisms in evaluations of aquatic ecosystems enables understanding the structure and functional processes of these systems. By calculating metrics of the assemblage of Chironomidae (Diptera) from remanso and corredeira mesohabitats, this study allowed identification of the state of preservation of nine low-order streams belonging to the Marmelos stream sub-basin, located in the municipality of Juiz de Fora, Minas Gerais, Brazil. The first chapter reports the results of two experiments. The first investigated the succession of Chironomidae from samples collected in bags containing Picramnia sellowii leaves, incubated in remansos and corredeirasof three streams in forested areas for 120 days. The changes in the composition and structure of the fauna were attributed mainly to the leaf mass loss and physical heterogeneity of the detritus, especially when the leaf decomposition reached 50% (60 days), at which point the greatest richness of taxa was observed. After 30 days, the dominance of larvae of Stenochironomus possibly contributed to the greater physical fragmentation of the leaf litter. The absence of a relationship between non-mining Chironomidae and fungal biomass indicated that many larvae use the leaves only as substrate. Between the two mesohabitats, there was weak variation in the faunal composition. The second experiment, which compared the Chironomidae fauna in the bags containing leaves after decomposition for 60 days between streams in forested areas versus those in areas affected by organic pollution, detected a clear difference in the composition of taxa between the two environments. The Chironomidae metrics had a strong relation with the environmental variables that distinguished preserved and impacted streams, suggesting the use of this method to assess the environmental conditions of streams. The second chapter investigates whether the metrics of the Chironomidae assemblage differ between remansos and corredeirasin response to different land uses (forest, pasture and urban) in low-order streams, in the dry and rainy seasons. It was found that the taxon composition of both mesohabitats and seasons was the metric with greatest sensitivity to land use, suggesting that the use of this metric of one or the other mesohabitat or season of the year for the biomonitoring enables obtaining results that are less influenced by the natural variability of the environment and reduces the time for processing of the samples. The third chapter investigates the taxonomic concordance of benthic groups identified at different taxonomic levels. Genera of Chironomidae and genera of Ephemeroptera, Plecoptera and Trichoptera (EPT) were found to be concordant in the dry and rainy seasons. The same was found for the genera of Chironomidae and species of Oligochaeta. Families of macroinvertebrates were concordant with Chironomidae genera and EPT genera only in the dry season. Similar responses to the environmental variables were attributed to the concordance between groups, while the proximity of the streams resulted in absence of an influence of the spatial variables. The numerical resolution of Chironomidae genera in both seasons was found to be effective, while this only occurred for the Oligochaeta species in the dry season. The percentage of information lost (>15%) indicates caution in using data on the presence/absence of these groups, suggesting use of this type of investigation only for rapid assessments in environments with marked differences in their preservation conditions.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2016-08-09T15:38:02Z No. of bitstreams: 1 guilhermeaugustodasilveira.pdf: 1284583 bytes, checksum: cd2152b32ccbfdb57ae8224070af4508 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-08-10T12:45:18Z (GMT) No. of bitstreams: 1 guilhermeaugustodasilveira.pdf: 1284583 bytes, checksum: cd2152b32ccbfdb57ae8224070af4508 (MD5) / Made available in DSpace on 2016-08-10T12:45:18Z (GMT). No. of bitstreams: 1 guilhermeaugustodasilveira.pdf: 1284583 bytes, checksum: cd2152b32ccbfdb57ae8224070af4508 (MD5) Previous issue date: 2016-02-26 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nascentes são ecossistemas estáveis, onde a conectividade aquático-terrestre e a complexidade de microhabitats que apresentam permitem que estes ambientes suportem uma fauna diversa. Considerando a importância das nascentes na manutenção da biodiversidade de organismos aquáticos e sua relevância econômica e ecológica, aliado à escassez de estudos em ambientes tropicais, o presente estudo objetivou testar os modelos das teorias de nicho e neutra, bem como quantificar a importância do espaço e das variáveis ambientais como agentes estruturadores das comunidades de invertebrados em nascentes. Foram obtidas três amostras compostas de substratos (pedras, areia e folhiço) em quinze nascentes de cinco localidades no município de Juiz de Fora, Minas Gerais, Brasil. Um total de 11.239 invertebrados foram identificados. As nascentes do tipo helocreno, com área alagada difusa, e reocreno, cuja água ao sair do solo forma imediatamente um riacho apresentaram maior abundância e riqueza de invertebrados que limnocreno, nascentes que formam poça. A composição da fauna também diferiu entre os três tipos estudados, o que pode ser explicado pela heterogeneidade ambiental encontrada nestas nascentes e pelas diferenças físicas e químicas entre os diferentes tipos. Os resultados da análise de Redundância parcial mostraram que 23% da variação total da composição da fauna de invertebrados foram explicados pelas variáveis ambientais profundidade, temperatura da água, oxigênio dissolvido, pH, matéria orgânica e frações de areia média e areia muito fina, 4% foram explicados pela variação espacial e outros 12% pela interação entre estes fatores. Os 61% restantes corresponde à fração residual resultante de interações bióticas e outras variáveis não analisadas. Estes resultados podem ser relacionados ao efeito combinado entre os mecanismos enfatizados pela teoria de nicho e pela teoria neutra, e, portanto, estão de acordo com a abordagem de metacomunidades, seguindo o modelo de sorteamento de espécies de dinâmica de comunidades. Assim, pode-se concluir que os fatores ambientais e espaciais explicam parcialmente a estruturação da comunidade de invertebrados em nascentes, com maior importância dos filtros ambientais. / Springs are stable ecosystems, where the water-land connectivity and the complexity of microhabitats allow these environments to support a diverse fauna. Considering the importance of springs in the maintenance of biodiversity of aquatic organisms and their economic and ecological relevance and regarding with the lack of studies in tropical environments, the present study aimed to identify the influence of abiotic variables and spacial factors in the structuring of invertebrate communities in springs through a theoretical ecology approach. Three composite substrate samples (rocks, sand and litter) were obtained from 15 springs in five different areas in the city of Juiz de Fora, Minas Gerais, Brazil. A total of 11,239 invertebrates were identified. Helocrenes and rheocrene springs showed greater invertebrate abundance when compared to the limnocrene and the fauna composition differed between the three types of spring studied, which may be explained by the environmental heterogeneity found in helocrenes springs and physical and chemical differences between the different types. Results on the partial redundancy analysis showed that 23% of the total variation of the invertebrate fauna composition was explained through the measured environmental variables, while other 4% was explained by spatial variation; this can be related to the combined effect between mechanisms emphasized by the niche theory and neutral theory, and thus a agreeing with the metacommunities approach. So, we conclude that the environmental factors and space can partially explain the structure of invertebrate communities in springs, with greater importance of the environmental filters, the remainder being possibly explained by the biotic interactions and other non-analyzed variables.

A multi-scale approach for restoration site selection is presented and applied to an upland catchment, the River Ure, North Yorkshire. Traditional survey methods, advances in remote sensing, Geographical Information Systems (GIS) and risk-based fine sediment modelling using the SCIMAP module are combined to gather data at the catchment-scale through to the in-stream habitat-scale. The data gathered have been assessed against spatially distributed brown trout fry populations using Pearson’s correlation and multiple stepwise regressions. Fine sediment was shown to have a positive correlation with fry populations when upland drainage channels (grips) were added to the SCIMAP model. This suggests risk from peatland drainage is realised further down the catchment where eroded sediments are deposited. Farm-scale SCIMAP modelling was tested against farmers’ knowledge with variable results. It appears there is a cultural response to risk developed over generations. Management of meadows and pasture land through sub-surface drainage and stock rotation resulted in the risk being negated or re-routed across the holding. At other locations apparently low-risk zones become risky through less sensitive farming methods. This multi-scale approach reveals that the largest impacts on brown trout recruitment operate at the habitat-adjacent scale in tributaries with small upstream areas. The results show a hierarchy of impact, and risk-filters, arising from different intensity land management. This offers potential for targeted restoration site selection. In low-order streams it seems that restoration measures which exclude livestock, and provide bankside shading, can be effective. At such sites the catchment-scale shows a reduced signal on in-stream biota. Thus, brown trout stocks could be significantly enhanced by targeting restoration at riffle-habitat zones and adjacent land in order to disconnect the stream from farm-derived impacts and through adding structure to the stream channel.

L’évaluation de l’état écologique des rivières est régie par l’application de protocoles sur le terrain et au laboratoire. Ceux-ci induisent de nombreuses incertitudes tant naturelles qu’humaines. L’objectif de cette thèse est (1) d’étudier l’impact de certaines incertitudes sur les indices biologiques basés sur les macroinvertébrés et les macrophytes en rivière, (2) de les estimer et (3) d’observer leur propagation jusqu’à l’évaluation de la qualité écologique des rivières. Pour les macroinvertébrés, nous nous sommes intéressés à l’impact de la variation intra-substrat et à l’effet des variabilités liées aux compétences de l’opérateur dans les indices IBGN, IBG DCE et I2M2. Pour les macrophytes, nous nous sommes focalisés sur l’effet opérateur dans l’IBMR. Des variations des indices ont été observées jusqu’à conduire à une évaluation globale erronée. Des solutions correctives peuvent être proposées afin de réduire les effets des sources de variabilités étudiées. / Ecological status assessment in waterbodies depends on standards application in the field and in the laboratory. They induce many uncertainties associated to natural or human variabilities. The aim is (1) to study the effect of some uncertainties on french indices based on macroinverterbrates and macrophytes, (2) to estimate them, and (3) to observe their propagation on final ecologica lstatus. Concerning macroinvertebrates, we are interested in the intrasubstrate variability and the surveyor effect in IBGN, IBG DCE and I2M2. Concerning the macrophytes, we focus on surveyor impact in IBMR. Indices variation appears and could lead to ecological status changes. Control quality approach could be proposed to reduce uncertainties effects.

Abstract Understanding of natural and human induced changes to freshwater biodiversity patterns is critical for efficiently conserving and managing these highly impacted ecosystems. In this doctoral thesis, I study the natural spatial and temporal variability of littoral macroinvertebrate communities, as well as aquatic biodiversity responses (of bryophytes, macroinvertebrates and diatoms) to human impact on forested headwater streams. I also study the temporal variability of natural and human-impacted stream communities. I show that littoral macroinvertebrate communities are most variable between individual samples and to some extent between littorals, and that the diversity patterns of rare and common littoral macroinvertebrates vary at different spatial scales. Temporal (interannual) variability is of minor importance, particularly for the core species of the community. For rare species, however, the temporal component was generally more important than spatial turnover. For headwater streams, I show that most taxonomic groups responded negatively to human impact on the adjacent riparian forest. Nevertheless, pristine riparian forest is not a sufficient surrogate for stream biodiversity as also streams with relatively disturbed riparian forests supported diverse benthic communities. A rapid classification method based on the physical structure of the stream channel and its riparian forest is able to identify the reference-state communities, as well as the most severely altered communities, but a reliable identification of the intermediately-disturbed sites would need more precise information about the key stressors of stream communities. I found that fine sediments originating from forest drainage were the main factor causing reduction of stream biodiversity. I also found that forestry impacted streams varied temporally more than pristine streams, emphasizing the importance of interannual sampling of impacted streams for a reliable status assessment. / Tiivistelmä Luonnollisen ja ihmisen aiheuttaman biodiversiteettivaihtelun ymmärtäminen hoito- ja suojelutoimissa on tärkeää pienvesien monimuotoisuuden turvaamiseksi. Tarkastelen väitöskirjassani järvien rantavyöhykkeen pohjaeläinten ajallista ja paikallista vaihtelua sekä latvapurojen eliöyhteisöjen (pohjaeläimet, sammalet, piilevät) vasteita ihmisen aiheuttamaan fysikaaliseen muutokseen rantametsässä ja purouomassa. Tarkastelen myös ajallisen vaihtelun eroja luonnontilaisten ja ihmisvaikutteisten latvapurojen eliöyhteisöjen välillä. Osoitan, että järven rantavyöhykkeen pohjaeläinyhteisöt vaihtelevat eniten yksittäisten näytteiden välillä ja pienessä määrin eri rantojen välillä, mutta ajallinen vaihtelu ei heikennä tulosten luotettavuutta muiden kuin harvinaisten lajien osalta yhteen vuoteen rajoittuvassa näytteenotossa. Purotutkimuksissa osoitan, että useiden vesieliöryhmien lajirunsaus muuttuu ihmisen aiheuttaman rantametsän muutoksen seurauksena, mutta luonnontilaista rantametsää ei silti voida pitää yksiselitteisesti myös puron suojelutason mittarina, koska se ei välttämättä turvaa eliöiden lajistollista eheyttä suhteessa alkuperäiseen alueelliseen lajistoon. Rantametsän ja uoman fysikaalisiin rakennepiirteisiin perustuvaa nopeaa luokittelumenetelmää voidaan käyttää eliöyhteisöltään monimuotoisimpien ja metsätalouden voimakkaimmin rasittamien purojen tunnistamisessa. Eliöyhteisöltään lievemmin muutettujen purojen luotettavaan erotteluun luokittelun pitäisi kuitenkin sisältää tarkempaa tietoa metsäojitusten aiheuttamasta liettymisestä, joka on tulosteni perusteella haitallisin metsätaloudesta johtuva puroyhteisöjä rasittava tekijä. Havaitsin myös metsätalouden rasittamien purojen tilanarvioinnin toistettavuuden olevan luonnontilaisia puroja heikompaa, joten metsätalouden rasittamien purojen pidempiaikainen seuraaminen tuntuu välttämättömältä luotettavien tilanarvioiden tuottamiseksi.

>Magister Scientiae - MSc / The water quality in many Cape Town Rivers and streams is a major challenge. Kuils River is subject to multiple land use impacts from upstream to downstream because of rapid urbanization in its catchment area. The main pollution sources are urban and industrial, organic matter from litter under the road-bridge, and golf course. However no systematic efforts have been made to evaluate and improve the health of the river in term of management. To assess impacts on water quality, this study was conducted from 4th September to 27th November 2012 in 5 selected sites in the upper reach of the Kuils river. The main aim was to compare the health of the river in 2012 with that found in 2005 using physical and chemical characteristics and the South Africa Scoring System (SASS). The statistical analysis showed a significant difference between and within sites. The water temperature, pH, dissolved oxygen concentration, total dissolved solids (TDS), and salinity were collected in situ by YSI 30 meter. To evaluate nutrient (nitrate and phosphorus) concentrations water samples were analyzed at UWC laboratory using spectrophotometer. In addition human activities, basic conditions (7.13 to 8.76), high total dissolved solids (416 to to 916.5 mg L¯¹) and salinity (0.31 to 0.71 mg L¯¹) concentrations were influenced by Malmesbury shales. Nitrate (0.1 to 3.1 mg L¯¹) and phosphorus (0.11 to 5.27 mg L¯¹) concentrations and the decrease in dissolved oxygen in November 2012 showed eutrophic conditions of the river. In the tributary site phosphorus (1.32 to 3.62 mg L¯¹) concentrations revealed hypertrophic condition compared to South Africa guideline. Macroinvertebrates sampled showed a total of 28 taxa grouped in 11 orders were sampled. Poor habitat diversity and water quality degradation were principal causes of low species diversity. The South Africa Score System version 5 (SASS5) and Average Score per Taxon (ASPT) indicated that the river is seriously impacted in 2012 compared to 2005 where water quality was in poor condition. The SASS and the ASPT scores were less than 50 and 4.2 at all sampling sites in most part of sampling period.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-22T10:04:57Z No. of bitstreams: 1 antonioteixeiradepaulajunior.pdf: 1054244 bytes, checksum: 9a7fcd05eea6d0d7ff59020571cb06a7 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T18:49:05Z (GMT) No. of bitstreams: 1 antonioteixeiradepaulajunior.pdf: 1054244 bytes, checksum: 9a7fcd05eea6d0d7ff59020571cb06a7 (MD5) / Made available in DSpace on 2016-01-25T18:49:05Z (GMT). No. of bitstreams: 1 antonioteixeiradepaulajunior.pdf: 1054244 bytes, checksum: 9a7fcd05eea6d0d7ff59020571cb06a7 (MD5) Previous issue date: 2014-02-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A fauna bromelícola propicia um alto potencial para o entendimento da ecologia de paisagens. Com a expansão das atividades agropecuárias, remanescentes florestais têm sido reduzidos a pequenas manchas de vegetação, tornando as espécies mais vulneráveis aos efeitos decorrentes dessa modificação da paisagem. O presente estudo visa caracterizar a estrutura das comunidades de invertebrados aquáticos em quatro morfoespécies de bromélias situadas entre 0 e 1,9m de altura em relação ao solo em um gradiente de distância da borda em direção ao interior de fragmentos florestais da Mata Atlântica que apresentam diferentes tamanhos, formas e distâncias entre si e estão localizados próximos a áreas de pastagens e florestas plantadas, em uma região da Serra da Mantiqueira (Brasil). Os grupos mais abundantes foram Ostracoda, Culicidae, Chironomidae e Scirtidae. Maior diversidade e riqueza foram encontradas nos fragmentos menos isolados, provavelmente pela maior facilidade de dispersão entre os indivíduos. A riqueza observada e a diversidade de invertebrados foram similares nas diferentes distâncias da borda, sugerindo ausência de influência do gradiente sobre a fauna de invertebrados bromelícolas nos fragmentos estudados. Com relação ao tipo de matriz, tanto a abundância como a riqueza observada foram similares em matriz de floresta plantada e pastagem. A composição de táxons também não variou em relação ao tipo de matriz. A diversidade, a riqueza e a composição faunística não tiveram relação com a altura da bromélia em relação ao solo, a morfoespécie e o volume de água coletado, também não houve diferença entre as bromélias do início das coletas e as do do final. Foi possível concluir que a estrutura e distribuição de invertebrados bromelícolas não foram influenciadas pelos efeitos do gradiente de distância nem pelo tipo de paisagem do entorno. / The bromeliad fauna provides a high potential to understanding the landscape ecology. With the expansion of agricultural activities, forest remnants have been reduced to small patches of vegetation, making the species more vulnerable to the effects of this landscape modification. This study aims to characterize the community structure of aquatic invertebrates in four morphospecies of bromeliads between 0 and 1.9 m height above the ground in a gradient from the edge to the interior of forest fragments of Atlantic Forest that have different sizes, shapes and distances apart and are located near areas of grassland and planted forests in a region of Serra da Mantiqueira (Brazil). The most abundant groups were Ostracoda, Culicidae, Chironomidae and Scirtidae. Greater diversity and richness were found in less isolated, probably by the ease of dispersion among fragments. The richness and diversity of invertebrates observed were similar in different distances from the edge, suggesting the absence of influence of the gradient on the invertebrate bromeliad fauna in the studied fragments. Regarding the type of matrix, both the abundance and richness observed were similar in planted forest and pasture. Nor does the composition of taxa varied in relation to the type of matrix. The diversity, richness and faunal composition were not associated with the bromeliad height from the ground, the morphospecies and the water volume gathered, there was no difference between the bromeliads of the beginning of the research and of the end. It was concluded that the structure and distribution of the bromeliad invertebrates were not influenced by the effects of the gradient away or by the type of the surrounding landscape.

The purpose of this study was to analyze the water quality of the micro-basin of Córrego da Areia Branca, through analysis of hydrologic (temperature, dissolved oxygen, pH, conductivity and clarity) and analysis of the benthic community of macroinvertebrates. Samplings were carried out at each fifth day in three distinctive sites of the micro-basin, from September 2005 to January 2006. The macroinvertebrates were identified at maximum level of family. It was carried out analysis of diversity and similarity to compare communities and Principal Component Analysis (PCA) of biotic and hydrologic factors. Seven families were found: Chironomidae, Tipulidae, Simuliidae, Psychodidae, Glossiphoniidae, Tubificidae and Lymnaeidae. The family Chironomidae was the most abundant in the three sites sampled. The origin (Site 1) showed the best water quality compared as the other sites due to riparian vegetation around. The Site 2, located at 500m from the origin, had decreased water quality, however, showed the highest diversity. The worst water quality was observed in Site 3 which had near zero dissolved oxygen coupled with the high conductivity values (average 537,2 S/cm). In such site, the taxons Chironomus, Psychodidae and Tipulidae were the most abundant. Conductivity and water clarity were the principal factors determining the low diversity of macroinvertebrates in the micro-basin. The findings of this study can be used as a baseline for further environmental monitoring for the future recovery of the Córrego da Areia Branca micro-basin. / Este trabalho teve como objetivo analisar a qualidade da água da microbacia do Córrego da Areia Branca por meio de análises de variáveis hidrológicas (temperatura, oxigênio dissolvido, pH, condutividade e transparência) e da composição da comunidade de macroinvertebrados bentônicos. Amostragens foram realizadas quinzenalmente no período de setembro de 2005 a janeiro de 2006 em três trechos distintos da microbacia, incluindo a nascente. Os macroinvetebrados foram identificados ao nível máximo de família. Foram efetuadas análises de diversidade e eqüidade para comparar as comunidades e Análise de Componentes Principais com os fatores bióticos e abióticos. Sete famílias foram amostradas: Chironomidae, Tipulidae, Simuliidae, Psychodidae, Glossiphoniidae, Tubificidae e Lymnaeidae. A família Chironomidae foi dominante nos três pontos de amostragens. A nascente apresentou melhor qualidade da água em relação aos outros dois trechos por apresentar vegetação ripária em seu entorno. O ponto 2, localizado a 500m a da nascente apresentou reduzida qualidade da água, entretanto, mostrou maior diversidade. O ponto 3 apresentou pior qualidade da água, com valores de OD próximos de 0 e condutividade média de 537,2 S/cm. Neste trecho, os táxons Chironomus, Psychodidae e Tipulidae foram os mais abundantes. A condutividade e a transparência da água foram os principais fatores determinando a baixa diversidade na microbacia. Os resultados deste estudo poderão servir como base para futuro monitoramento ambiental visando a recuperação da microbacia do Córrego da Areia Branca.

In this study, two different field experiments were designed to assess the relative influence of urbanization on benthic communities. During spring and summer, four urban and one reference sites from Denton County, Texas were selected for benthic macroinvertebrate evaluation. Statistically significant differences in colonized benthic macroinvertebrate taxa on artificial substrates were observed among the four urban sites and the reference site. Oligochaetes and chironomids were the dominant taxa at all sites. Identification of chironomid larvae at the subfamily and genus level to detect differences between sites had higher statistical power than the evaluation based on total chironomids. At the reference site, Caenis, Cladotanytarsus, Orthocladius, and Ceratopogonidae were the dominant taxa, while the urban sites were dominated by Dero, Physella, Ancylidae, Chironomus, Dicrotendipes, Glyptotendipes, Polypedilum, Pseudochironomus, Stenochironomus, and Tanytarsus. These differences may have been dependent upon differences in hydrologic regime and water quality between sites. Significant differences (ANOVA, p < 0.01) in water quality parameters (alkalinity, hardness, nitrates, phosphates, chlorides, sulfates, calcium, magnesium, potassium, and triazine) were found among water samples collected from the reference and urban sites. During the transfer period, most of the Ephemeroptera and Trichoptera taxa and a few other taxa disappeared from artificial substrates that were colonized at the reference site and then moved to the urban sites. Also, local abundant taxa from the urban site significantly (t test, p < 0.05) increased in number on the transferred artificial substrates. Seasonal differences in colonization patterns were also observed between the spring and summer experimental periods, which indicate that temporal variation is equally important, as is the anthropogenic effect in benthic community evaluation. Field survival and growth experiments using Erpetogomphus designatus larvae were designed to detect differences between evaluated sites. Larvae were collected from the reference site, measured in the laboratory, and exposed at the urban sites for six weeks in using specially designed cages. The exposed larvae demonstrated a higher mortality rate at the urban sites compared to the reference site.

Hydropower is an important source of renewable energy, but is often a cause of degradation to river ecosystems. Hydropeaking, i.e. the frequent alteration of discharge, is a process involved in hydropower generation and has been proven to affect aquatic organisms negatively. However, it’s unclear exactly what effects hydropeaking has on riverine ecology, in combination with important geomorphological characteristics. In this study, the interaction of hydropeaking and geological substrate (fine or coarse material) on aquatic macroinvertebrates was evaluated, while also assessing the influence of river width and water chemistry. Studies were conducted in 27 sites at rivers, 15 of which were exposed to hydropeaking, in central Sweden during June and August 2020. Sampling of macroinvertebrates was conducted using Hester-Dendy samplers. The following variables were investigated: i) total species richness, ii) species diversity, iii) macroinvertebrate density, iv) EPT (Ephemeroptera, Plecoptera, and Trichoptera) species richness, v) % EPT, vi) EPT/Chironomidae ratio, and vii) % Oligochaeta. The effects of hydropeaking and geological substrate on these variables were assessed using AIC model selection. Results did not indicate interaction effects of hydropeaking and geological substrate on any variable, and this did not concur with stated hypotheses. The results reaffirm the complexity of disentangling the effects that are in play during these processes. Studies of this kind is important in understanding how hydropower affects macroinvertebrates, and provides information on where and how most effective mitigation measures should be applied and provides valuable information for improving hydropower management protocols. / Vattenkraft är en viktig källa till förnybar energi, men är ofta en orsak till försämring av ekosystem hos älvar. Korttidsreglering, dvs. den frekventa förändringen av vattenflöde, är en process som är involverad i vattenkraftsproduktion och har visat sig påverka vattenlevande organismer negativt. Det är dock oklart exakt vilka effekter korttidsreglering har på älvens ekologi, i kombination med viktiga geomorfologiska egenskaper. I denna studie utvärderades interaktionen mellan korttidsreglering och geologiskt substrat (fint eller grovt material) på akvatiska makroevertebrater, samtidigt som påverkan av älvbredd och vattenkemi utvärderades. Studier utfördes på 27 platser lokaliserade vid älvar, av vilka 15 var utsatta för korttidsreglering, i centrala Sverige under juni och augusti 2020. Provtagning av makroevertebrater utfördes med Hester-Dendy-provtagare. Följande responsvariabler undersöktes: i) total artrikedom, ii) artdiversitet, iii) densitet av makroevertebrater, iv) artrikedom av EPT (Ephemeroptera, Plecoptera och Trichoptera), v) % EPT, vi) EPT/Chironomidae-förhållande samt vii) % Oligochaeta. Effekterna av korttidsreglering och geologiskt substrat på dessa variabler bedömdes med hjälp av AIC-modellval. Resultaten indikerade inte interaktionseffekter av korttidsreglering och geologiskt substrat på någon responsvariabel, och detta överensstämde inte med angivna hypoteser. Resultaten bekräftar komplexiteten i att utvärdera de effekter som har en påverkan under dessa processer. Studier av detta slag är viktiga för att förstå hur vattenkraft påverkar makroevertebrater, och ger information om var och hur de mest effektiva åtgärderna bör tillämpas och ger värdefull information för att förbättra hantering av vattenkraft. / Korttidsregleringens påverkan på biologin varierar med vattendragets geomorfologi