This thesis contributes to an increased understanding of the formation of dioxins and dioxin-like compounds in combustion processes. Although emissions to air from waste incineration facilities have been greatly reduced by the use of efficient air pollution control measures, the resulting residues (ashes and filters) are highly toxic and are classified as hazardous waste. The main objective of the work underlying this thesis was to elucidate the formation and chlorination pathways of dioxins and dioxin-like compounds in waste combustion flue gases in the temperature range 640-200°C in a representative, well-controlled laboratory-scale reactor using artificial municipal solid waste. This could contribute to the reduction of harmful emissions to air and also reduce the toxicity of waste incineration residues, thus reducing or even eliminating the need for costly and potentially hazardous after-treatment. A comparison of four different quenching profiles showed that the formation of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) was rapid and mainly occurred in the 640-400°C temperature region, with high dependency on sufficient residence time within a specific temperature region. Prolonged residence time at high temperatures (450/460°C) reduced the PCDD yields, even at lower temperatures along the post-combustion zone. PCDD, PCDF and PCN (polychlorinated naphthalene) isomer distribution patterns indicated contributions from chlorophenol condensation as well as chlorination reactions for all three classes of compounds. The formation of PCDDs was largely influenced by chlorophenol condensation and to some extent by chlorination reactions. For the PCDFs, chlorine substitution adjacent to the oxygen bridges was unfavoured, as demonstrated by the notably lower abundance of 1,9-substituted congeners. This was supported by bidirectional orthogonal partial least squares (O2PLS) modelling. The variable with the greatest influence on the distribution of PCDD congeners was the relative free energy (RΔGf). The O2PLS models displayed distinct clusters, dividing most of the homologues into two or three sub-groups of congeners which seemed to correspond to the probability of origination from chlorophenol condensation. The effects of injection of aromatic structures into the flue gas differed for each class of compounds. Injection of naphthalene increased the formation of monochlorinated naphthalene but the remaining homologues appeared to be unaffected. This was probably due to insufficient residence time at temperatures necessary for further chlorination. Injected dibenzo-p-dioxin was decomposed, chlorinated and re-condensated into PCDDs and PCDFs, whereas injection of dibenzofuran and fluorene reduced the PCDD levels in the flue gas. / Denna avhandling fokuserar på olika aspekter som kan bidra till en ökad förståelse av bildning av dioxiner och dioxin-lika föreningar i förbränningsprocesser. Även om utsläppen till luft från sopförbränningsanläggningar har minskat kraftigt tack vare effektiva rökgasreningsmetoder, så återstår problemet med mycket giftiga rökgasreningsprodukter (askor och filter), vilka klassificeras som farligt avfall. Det huvudsakliga syftet med arbetet bakom denna avhandling var att klarlägga bildnings- och kloreringsvägarna för dioxiner och dioxin-lika föreningar i temperaturintervallet 640-200°C i rökgaser från sopförbränning. Detta kan möjliggöra lösningar för ytterligare emissionsminskningar och en avgiftning av biprodukterna från avfallsförbränning, vilket minskar eller till och med eliminerar behovet av kostsam och riskfylld efterbehandling. Realistiska och välkontrollerade försök har utförts i en lab-skalereaktor där en artificiell hushållssopa har förbränts. En jämförelse av fyra olika temperatur- och uppehållstidsprofiler visade att bildning av polyklorerade dibenso-p-dioxiner (PCDD) och dibensofuraner (PCDF) sker snabbt och huvudsakligen inom temperaturintervallet 640-400°C. Bildningen var starkt beroende av en tillräckligt lång uppehållstid inom ett visst temperaturområde. En förlängd uppehållstid vid höga temperaturer (>450°C) resulterade i minskade halter av PCDD, vilka förhöll sig låga även senare i efterförbränningszonen. Isomermönstren av PCDD, PCDF och PCN (polyklorerade naftalener) visade alla tecken på att härröra från både klorfenolkondensation och kloreringsreaktioner. PCDD-mönstret visade tydliga indikationer på bildning från klorfenoler, och till mindre grad bildning via klorering. För PCDF var klorsubstitution i positioner angränsande till syrebryggan missgynnad, vilket bekräftades av multivariat modellering (O2PLS). Den variabel som starkast påverkade bildningen av PCDD var relativa fria energin (RΔGf). Modellerna visade på en distinkt gruppering av PCDD- och PCDF-kongenerna i två eller tre grupper för varje kloreringsgrad, och föreslås vara relaterad till sannolikheten för respektive kongen att bildas via klorfenolkondensation. Injektion av aromatiska kolstrukturer i rökgaskanalen gav upphov till skilda effekter. Injektion av naftalen ökade bildningen av monoklorerad naftalen medan resterande homologer inte verkade påverkas, sannolikt på grund av för kort uppehållstid för ytterligare klorering. Dibenso-p-dioxin spjälkades sannolikt till fenoliska fragment som klorerades och sedan återkondenserades till PCDD och PCDF, medan dibensofuran och fluoren kraftigt reducerade PCDD-koncentrationerna.

No estudo das comunidades florestais, estabelecer a importância relativa dos fatores que definem a composição e a distribuição das espécies é um desafio. Em termos de gradientes ambientais o estudo das respostas das espécies arbóreas são essenciais para a compreensão dos processos ecológicos e decisões de conservação. Neste sentido, para contribuir com a elucidação dos processos ecológicos nas principais formações florestais do Estado de São Paulo (Floresta Ombrófila Densa de Terras Baixas, Floresta Ombrófila Densa Submontana, Floresta Estacional Semidecidual e Savana Florestada) este trabalho objetivou responder as seguintes questões: (I) a composição florística e a abundância das espécies arbóreas, em cada unidade fitogeográfica, variam conforme o gradiente edáfico e topográfico?; (II) características do solo e topografia podem influenciar na previsibilidade de ocorrência de espécies arbóreas de ampla distribuição em diferentes tipos vegetacionais? (III) existe relação entre o padrão de distribuição espacial de espécies arbóreas e os parâmetros do solo e topografia? O trabalho foi realizado em parcelas alocadas em unidades de conservação (UC) que apresentaram trechos representativos, em termos de conservação e tamanho, das quatro principais formações florestais presentes no Estado de São Paulo. Em cada UC foram contabilizados os indivíduos arbóreos (CAP ≥ 15 cm), topografia, dados de textura e atributos químicos dos solos em uma parcela de 10,24 ha, subdividida em 256 subparcelas. Análises de correspodência canônica foram aplicadas para estabelecer a correspondência entre a abundância das espécies e o gradiente ambiental (solo e topografia). O método TWINSPAN modificado foi aplicado ao diagrama de ordenação da CCA para avaliar a influência das variáveis ambientais (solo e topografia) na composição de espécies. Árvores de regressão \"ampliadas\" (BRT) foram ajustadas para a predição da ocorrência das espécies segundo as variáveis de solo e topografia. O índice de Getis-Ord (G) foi utilizado para determinar a autocorrelação espacial das variáveis ambientais utilizadas nos modelos de predição da ocorrência das espécies. Nas unidades fitogeográficas analisadas, a correspondência entre o gradiente ambiental (solo e topografia) e a abundância das espécies foi significativa, especialmente na Savana Florestada onde observou-se a maior relação. O solo e a topografia também se relacionaram com a semelhança na composição florística das subparcelas, com exceção da Floresta Estacional Semicidual (EEC). As principais variáveis de solo e topografia relacionadas a flora em cada UC foram: (1) Na Floresta Ombrófila Densa de Terras Baixas (PEIC) - teor de alumínio na camada profunda (Al (80-100 cm)) que pode refletir os teor de Al na superfície, acidez do solo (pH(H2O) (5-25 cm)) e altitude, que delimitou as áreas alagadas; (2) Na Floresta Ombrófila Densa Submontana (PECB) - altitude, fator que, devido ao relevo acidentado, influencia a temperatura e incidência de sol no sub-bosque; (3) Na Savana Florestada (EEA) - fertilidade, tolerância ao alumínio e acidez do solo. Nos modelos de predição BRT, as variáveis químicas dos solos foram mais importantes do que a textura, devido à pequena variação deste atributo no solo nas áreas amostradas. Dentre as variáveis químicas dos solos, a capacidade de troca catiônica foi utilizada para prever a ocorrência das espécies nas quatro formações florestais, sendo particularmente importante na camada mais profunda do solo da Floresta Ombrófila Densa de Terras Baixas (PEIC). Quanto à topografia, a altitude foi inserida na maioria dos modelos e apresentou diferentes influências sobre as áreas de estudo. De modo geral, para presença das espécies de ampla distribuição observou-se uma mesma tendência quando à associação com os atributos dos solos, porém com amplitudes dos descritores edáficos que variaram de acordo com a área de estudo. A ocorrência de Guapira opposita e Syagrus romanzoffiana, cujo padrão variou conforme a escala, foi explicada por variáveis com padrões espaciais agregados que somaram entre 30% e 50% de importância relativa no modelo BRT. A presença de A. anthelmia, cujo padrão também apresentou certo nível de agregação, foi associada apenas a uma variável com padrão agregado, a altitude (21%), que pode ter exercido grande influência na distribuição da espécie ao delimitar áreas alagadas. T. guianensis se associou a variáveis ambientais preditoras com padrão espacial agregado que somaram cerca de 70% de importância relativa, o que deve ter sido suficiente para estabelecer o padrão agregado em todas as escalas. No entanto, a influência dos fatores ambientais no padrão de distribuição da espécie não depende apenas do ótimo ambiental da espécie, mas um resultado da interação espécie-ambiente. Concluiu-se que: (I) características edáficas e topográficas explicaram uma pequena parcela da composição florística, em cada unidade fitogeográfica, embora a ocorrência de algumas espécies tenha se associado ao gradiente edáfico e topográfico; (II) a partir de características dos solos e da topografia foi possível prever a presença de espécies arbóreas, que apresentaram particularidades em relação a sua associação com o solo de cada fitofisionomia; (III) a partir de associações descritivas o solo e a topografia influenciam o padrão de distribuição espacial das espécies, na proporção em que contribuem para a presença das mesmas. / In the study of forest communities, establish the relative importance of the factors that define the composition and distribution of species is a challenge. In terms of environmental gradients study the responses of tree species are essential to the understanding of ecological processes and conservation decisions. In this regard, to contribute to the elucidation of ecological processes in the main forest formations of São Paulo (Dense Ombrophylous Forest of Lowlands, Submontane Dense Ombrophylous Forest, Semideciduous Forest and Savanna Woodland) this study aimed to answer the following questions: (I) floristic composition and tree species abundance in each phytogeographic unit change according to edaphic and topographic gradient?; (II) soil characteristics and topography can influence the occurrence of predictability of tree species widely distributed in different types of vegetation? (III) there is a relationship between spatial distribution pattern of tree species and the soil parameters and topography? The work was carried out in allocated plots in protected areas (PA) with the four main forest formations in terms of conservation and size of Sao Paulo. In each PA was sampled individual trees, topography, texture data and chemical properties of the soil on a plot of 10.24 ha, subdivided into 256 subplots. Canonical corresponding analyzes (CCA) were applied to establish the correspondence between the abundance of species and environmental gradient (soil and topography). The modified TWINSPAN method was applied to CCA ordination diagram to evaluate the influence of environmental variables (soil and topography) on species composition. Boosteed Regression Trees (BRT) were adjusted for predicting the occurrence of the species according to soil variables and topography. The Getis Ord-index (G) was used to determine the spatial autocorrelation of environmental variables used in the BRT models. In analyzed phytogeographic units, correspondence between the environmental gradient (soil and topography) and abundance of species was significant, especially in Savanna Woodland. The soil and topography also correlated with the floristic composition similarity of the subplots, with the exception of Semicidual Seasonal Forest (EEC). The main soil and topography variables related to floristic in each PA were: (1) Dense Ombrophylous Forest of Lowlands (PEIC) - aluminium content in the deep layer (Al (80-100 cm)) which may reflect the Al content at the surface, soil acidity (pH (H2O) (5-25 cm)) and altitude, which outlined the flooded areas; (2) Submontane Dense Ombrophylous Forest (PECB) - elevation, due to the rugged terrain influences the temperature and light incidence in the understory; (3) Savanna Woodland (EEA) - fertility, tolerance to aluminum and soil acidity. In BRT prediction models, the chemical soil variables were more important than the texture due to small variation of this soil attribute in the sampled area. Among the soil chemical variables, cation exchange capacity was used to predict the species occurrence in four forest formations and particularly important in the soil deepest layer on the Dense Ombrophylous Forest of Lowlands (PEIC). In relation to topography, elevation was included in most models and had different influences on the study areas. Overall, the species widely distributed showed the same trend as the association with the attributes of the soil, but with amplitudes of edaphic descriptors that change according to the study area. The occurrence of the Guapira opposita and Syagrus romanzoffiana, whose pattern change according to the scale, was explained by variables with aggregated spatial patterns that amounted to between 30% and 50% relative importance in the BRT model. The presence of A. anthelmia, which defaults also presented certain level of aggregation, was associated only with one aggregate variable, elevation (21%), which may have exerted great influence on the species distribution to delimit wetlands. T. guianensis was related with the predictive environmental variables of aggregate spatial pattern which totaled to about 70% relative importance, what must have been enough to establish the aggregate pattern at all scales. However, the influence of environmental factors (soil and topography) on the species distribution pattern depends not only on the environmental optimum of the species, but a result of species-environment interaction. We concluded that: (I) soil and topographical characteristics explain a small portion of the floristic composition in each phytogeographic unit, although the occurrence of some species have been associated to the soil and topographic gradient; (II) from soil characteristics and topography it was possible to predict the presence of tree species, which showed particular in relation to its association with the soil of each vegetation type; (III) from descriptive associations soil and topography influence the spatial distribution pattern of the species, to the extent that contribute to the presence of the same.

The observational study on natural regeneration of Norway spruce (Picea abies) was provided during seasons 2010 and 2011 in the windthrow area of High Tatra National Park. The main aim of this master thesis was to describe the distribution pattern in Norway spruce regeneration as well as to estimate the spatial scale, which most preciselly describes the differences in its phenotypic variability. Following step was to determine the relative influence of abiotic and stand factors on the growth characteristics and abundance of spruce seedlings. The Main focus lied on stressing the role of biotic interactions, like intraspecific and interspecific competition, leading to certain discrepancies in the phenotype, as well as in abundance of spruce seedlings.The reponse in variability in spruce traits was recognized at each spatial level. The results showed clear causality between soil moisture and vegetation composition, which both directly modified not only the phenotype of spruce seedlings and plants, but have even influenced their counts on particular stands.

I Fredriksdalsvikens naturreservat i Kristianstads kommun skedde omfattande metalläckage efter en översvämning sommaren 2007 som orsakade skador på djur- och växtliv. De kraftiga metalläckagen misstänks härledas till sura sulfatjordar. Sura sulfatjordar tillhör de miljöskadligaste jordarna i världen på grund av de kraftiga metalläckagen och försurningen som jordarna orsakar till omgivningen. Mot bakgrund till humusämnens centrala roll för metalltransport i naturliga miljöer, syftade denna studie till att kartlägga hur organiskt kol är fördelat, sprids samt hur det kan förklaras i ett område nära det drabbade naturreservatet. Studien är en del av ett pågående forskningsprojekt i området som bedrivs på Linnéuniversitetet. I studiens undersökningsområde dominerar jordbruksmark som dräneras av ett dikessystem från norr till söder. Vattnet som avleds i dikessystemet pumpas slutligen till en våtmark i Fredriksdalsvikens naturreservat. I studien analyserades jord från åkermark, dikessediment, porvatten och dikesvatten från området på totalt organiskt kol med metoderna glödförlust och kyvett-test. Totalhalterna jämfördes med pH och grundvattennivå i åkermark. Resultat och slutsatser av studien är att högst halter löst organiskt kol uppmättes i dikesvattnet uppströms i dikessystemet och beror troligtvis på bottenfauna som inte växer i andra delar av systemet. I dikessediment ökar den organiska halten nedströms i dikessystemet och kan förklaras genom tillförsel av organiskt kol från två diken som dränerar åkermark rik på organiskt kol. De högsta halterna organiskt kol i jord beror på ett tunt torvlager. I åkermark visar inte resultaten någon tydlig statistisk korrelation mellan pH och totalt organiskt kol, men kraftig pH-sänkning tillsammans med höga totalhalter organiskt kol i torvjord beror troligtvis snarare på humusämnen än på sur sulfatjord. I åkermark väster om dikessystemet ökar den organiska halten med djupet under grundvattenytan. I samma åkermark ökar halterna av totalt organiskt kol lateralt mot dikessystemet, parallellt med att pH sjunker som troligen påverkas av starkare bindningsmekanismer till mineral, lägre mikrobiell aktivitet och minskad urlakning av löst organiskt kol. Men fler undersökningar i området krävs då markanvändning, erosion, jordarternas textur och sammansättning samt vattnets spridningsvägar också är avgörande faktorer för fördelning och spridning av organiskt kol i naturliga miljöer. / In the nature reserve Fredriksdalsviken in Kristianstad municipality, extensive metal leakage occurred after a flood in the summer of 2007 that caused damage to wildlife and plant life. The heavy metal leaks are suspected to be derived from acid sulphate soils in the area. Acid sulphate soils are among the most environmentally harmful soils in the world due to its extensive acidification and leaching of metals to the environment. In the light of humic substances key role for metal transport in natural environments, this study aimed to investigate how organic carbon is distributed, spread and how it can be explained in an area near the affected nature reserve. The study is part of an ongoing research project in the area conducted at Linnaeus University. The study area is dominated by agriculture land which is drained by a ditch system from north to south. The drained water in the ditch system is finally pumped to a wetland in the Fredriksdalsviken nature reserve. In the area, total organic carbon was analysed on soil from arable land, ditch sediment, pore water and ditch water with the methods loss of ignition and cuvette-test. Total levels were compared with pH and the groundwater level in arable land. The results and conclusions of the study are that the highest content of dissolved organic carbon in the ditch water upstream the ditch system is probably due to benthic fauna that doesn’t grow in other parts of the system. In the ditch sediment, the organic content increases downstream in the ditch system and can be explained by the supply of organic carbon from two ditches that drain arable land rich in organic carbon. In arable land are the highest levels of organic carbon due to a thin peat layer. The results does not show a clear statistical correlation between pH and total organic carbon in soil, but a sharp decrease in pH together with high total levels of organic carbon in peat soil is probably due to humic substances rather than to acid sulphate soil. In the western arable land of the ditch system, levels of total organic carbon increase laterally towards the ditch system at the same time as the pH decreases, which is probably affected by stronger binding mechanisms to minerals, lower microbial activity and reduced leaching of dissolved organic carbon. However, more research is required in the study area, since land use, erosion, soil texture and constitution together with the flow paths of water also are crucial factors for the distribution and pathways of organic carbon in natural environments.

In den Jahren 2005 bis 2010 erfolgte im Rahmen der Erarbeitung der vorliegenden Dissertationsschrift eine ökologische Untersuchung der Chironomidenfauna in der Talsperre Saidenbach (Sachsen, Erzgebirge). Drei Arten mit hoher Abundanz konnten bei der umfassenden Artenanalyse im Jahr 2005 ermittelt werden: Procladius crassinervis, P. choreus und Chironomus anthracinus. Zusätzlich wurde die Art C. plumosus aufgrund ihrer engen Verwandtschaft zu C. anthracinus in die Untersuchung einbezogen. Die Arbeit ist auf vier Schwerpunkte fokussiert, wobei die Larven und Puppen der vier Arten analysiert wurden. (1) Die Erarbeitung einer zuverlässigen Methode zur Unterscheidung der Larven der beiden eng verwandten Procladius-Arten basierend auf morphologischen Kriterien (Imaginalscheiden-entwicklung, Kopfkapselgröße und Körperlänge) sowie die Tiefenverteilung der Puppen waren eine Vorbedingung für weiterführende Analysen des Lebenszyklus (LZ) dieser beiden Arten. (2) Die Untersuchung des LZ war der zweite Schwerpunkt. Der LZ wurde stark von abiotischen Faktoren wie Temperatur, Sauerstoff und Biovolumen des Phytoplanktons kontrolliert. (3) Die raum-zeitlichen Verteilungsmuster der vier Arten wurden zunächst bezüglich großräumiger Unterschiede über einen Tiefengradienten innerhalb eines Transektes analysiert. Hierbei zeigte sich bei allen vier Arten eine zeitliche Änderung im jeweiligen Hauptverbreitungsgebiet. Die jungen Larven von C. anthracinus, C. plumosus und P. choreus wanderten im Verlauf ihrer Entwicklung bis zur Verpuppung in flachere Bereiche, P. crassinervis wanderte in tiefere Bereiche. Die Analyse der Verteilungsunterschiede der Larven zwischen zwei verschieden stark eutrophierten Buchten ergab höhere Dichten der beiden Chironomus-Arten in der Bucht mit dem größeren Zulauf und der höheren Phytoplanktonkonzentration im Vergleich mit den anderen Arten. Eine Analyse des kleinräumigen Verteilungsmusters fokussierte auf der Frage, ob die Larven gleichmäßig verteilt oder aggregiert auftraten. Die Untersuchung des vertikalen Verteilungsmusters erforschte das Schwimmverhalten der Larven. (4) Der letzte Aspekt war eine experimentelle Untersuchung, die am Beispiel von C. anthracinus durchgeführt wurde mit dem Ziel, den Proximatfaktor für die beobachtete Wanderung der Larven zu ermitteln, der letztendlich die Temperatur war. Puppen bevorzugten im Experiment wärmere Temperaturen und junge Larven kühlere Temperaturen. Die fünfjährige Untersuchung der Chironomiden in der Talsperre Saidenbach beschreibt insgesamt die komplexe Verhaltensreaktion der Chironomiden, die einen wesentlichen Teil der benthischen Lebensgemeinschaft darstellen, bezüglich der Lebenszyklusmuster (Voltinismus, Verpuppung), der Abundanzänderungen (inner- und zwischenjährlich) sowie der groß- und kleinräumigen Verteilung unter der Einwirkung der wichtigsten Umweltfaktoren. / In the context of the present dissertation an ecological study was performed about chironomids in Saidenbach Reservoir in the Saxony Ore Mountains, Germany during the five years from 2005 to 2010. A preliminary overall species analysis in 2005 showed that three species were most abundant: Procladius crassinervis, P. choreus and Chironomus anthracinus. Additionally, the species C. plumosus was examined because of its close relationship to C. anthracinus. The study is focussed on four subjects, whereby larvae and pupae of the four species were analysed. (1) The elaboration of a reliable method to distinguish the larvae of the two closely related species P. crassinervis and P. choreus on the basis of morphological criteria (imaginal disc development, larval head capsule size and body length) as well as the depth distribution of their pupae was a precondition to the profound analysis of their life cycles. (2) The investigation of the life cycle pattern of the four species was the second focus. The life cycle of the four species was found to be strongly influenced by abiotic conditions such as temperature, oxygen and biovolume of the phytoplankton. (3) The spatial and temporal distribution pattern of the four species was analysed in view of large scale differences over a depth gradient in one transect. Here, in all four species a shift in the mainly settled lake bottom area occurred. The young larvae of C. anthracinus, C. plumosus and P. choreus migrated during maturing and pupation towards shallower areas; P. crassinervis migrated to deeper areas. The distribution differences between two different bays showed that the two Chironomus species had higher densities in the bay with the higher inflow which resulted in a higher phytoplankton standing stock compared to the other species. A small scale distribution pattern analysis focussed on finding out whether the larvae were aggregated or randomly distributed. The vertical distribution analysis examined the swimming behaviour of the larvae. (4) The last aspect was an experimental setup exemplarily driven with C. anthracinus which showed that the migration was stimulated by the proximate factor temperature as pupae preferred warmer temperatures and young larvae colder temperatures. Altogether, the five year study about chironomids in Saidenbach Reservoir pointed out the complex reaction in the behaviour of an important part of the benthic community concerning the life cycle pattern (voltinism, pupation pattern), the changing in abundances (inter-annual and intra-annual) and the large scale and small scale distribution pattern under the rule of the most important environmental factors.

In den Jahren 2005 bis 2010 erfolgte im Rahmen der Erarbeitung der vorliegenden Dissertationsschrift eine ökologische Untersuchung der Chironomidenfauna in der Talsperre Saidenbach (Sachsen, Erzgebirge). Drei Arten mit hoher Abundanz konnten bei der umfassenden Artenanalyse im Jahr 2005 ermittelt werden: Procladius crassinervis, P. choreus und Chironomus anthracinus. Zusätzlich wurde die Art C. plumosus aufgrund ihrer engen Verwandtschaft zu C. anthracinus in die Untersuchung einbezogen. Die Arbeit ist auf vier Schwerpunkte fokussiert, wobei die Larven und Puppen der vier Arten analysiert wurden. (1) Die Erarbeitung einer zuverlässigen Methode zur Unterscheidung der Larven der beiden eng verwandten Procladius-Arten basierend auf morphologischen Kriterien (Imaginalscheiden-entwicklung, Kopfkapselgröße und Körperlänge) sowie die Tiefenverteilung der Puppen waren eine Vorbedingung für weiterführende Analysen des Lebenszyklus (LZ) dieser beiden Arten. (2) Die Untersuchung des LZ war der zweite Schwerpunkt. Der LZ wurde stark von abiotischen Faktoren wie Temperatur, Sauerstoff und Biovolumen des Phytoplanktons kontrolliert. (3) Die raum-zeitlichen Verteilungsmuster der vier Arten wurden zunächst bezüglich großräumiger Unterschiede über einen Tiefengradienten innerhalb eines Transektes analysiert. Hierbei zeigte sich bei allen vier Arten eine zeitliche Änderung im jeweiligen Hauptverbreitungsgebiet. Die jungen Larven von C. anthracinus, C. plumosus und P. choreus wanderten im Verlauf ihrer Entwicklung bis zur Verpuppung in flachere Bereiche, P. crassinervis wanderte in tiefere Bereiche. Die Analyse der Verteilungsunterschiede der Larven zwischen zwei verschieden stark eutrophierten Buchten ergab höhere Dichten der beiden Chironomus-Arten in der Bucht mit dem größeren Zulauf und der höheren Phytoplanktonkonzentration im Vergleich mit den anderen Arten. Eine Analyse des kleinräumigen Verteilungsmusters fokussierte auf der Frage, ob die Larven gleichmäßig verteilt oder aggregiert auftraten. Die Untersuchung des vertikalen Verteilungsmusters erforschte das Schwimmverhalten der Larven. (4) Der letzte Aspekt war eine experimentelle Untersuchung, die am Beispiel von C. anthracinus durchgeführt wurde mit dem Ziel, den Proximatfaktor für die beobachtete Wanderung der Larven zu ermitteln, der letztendlich die Temperatur war. Puppen bevorzugten im Experiment wärmere Temperaturen und junge Larven kühlere Temperaturen. Die fünfjährige Untersuchung der Chironomiden in der Talsperre Saidenbach beschreibt insgesamt die komplexe Verhaltensreaktion der Chironomiden, die einen wesentlichen Teil der benthischen Lebensgemeinschaft darstellen, bezüglich der Lebenszyklusmuster (Voltinismus, Verpuppung), der Abundanzänderungen (inner- und zwischenjährlich) sowie der groß- und kleinräumigen Verteilung unter der Einwirkung der wichtigsten Umweltfaktoren.:1. GENERAL INTRODUCTION 2. MORPHOLOGICAL DIFFERENTIATION OF TWO PROCLADIUS AND TWO CHIRONOMUS SPECIES IN THE MESOTROPHIC SAIDENBACH RESERVOIR 2.1 Introduction 2.2 Material and methods 2.2.1 Sampling of larvae 2.2.2 Species identification 2.2.3 Differentiation of the Procladius species by means of head capsule size and depth distribution 2.2.4 Other morphological criteria 2.2.5 Development of imaginal discs 2.3. Results 2.3.1 Procladius crassinervis and P. choreus 2.3.2 Chironomus anthracinus and C. plumosus 2.4. Discussion 2.4.1 Method discussion 2.4.2 Head capsule width 2.4.3 Larval growth 3. FIVE - YEAR LIFE CYCLE PATTERN OF TWO PROCLADIUS AND TWO CHIRONOMUS SPECIES IN THE MESOTROPHIC SAIDENBACH RESERVOIR 3.1 Introduction 3.2 Material and methods 3.2.1 Study area 3.2.2 Sampling of chironomid larvae 3.2.3 Sampling of chironomid pupae 3.2.4 Mortality 3.2.5 Abiotic conditions and phytoplankton 3.3 Results 3.3.1 Abiotic conditions and phytoplankton 3.3.1.1 Temperature 3.3.1.2 Oxygen 3.3.1.3 Phytoplankton 3.3.2 Life cycle analysis 3.3.2.1 Composition of instars 3.3.2.2 Procladius crassinervis 3.3.2.3 Procladius choreus 3.3.2.4 Chironomus anthracinus 3.3.2.5 Chironomus plumosus 3.3.2.6 Tanytarsini 3.3.2.7 Other species 3.3.3 Influence of abiotic conditions on pupation and life cycle 3.3.3.1 Procladius crassinervis 3.3.3.2 Procladius choreus 3.3.3.3 Chironomus anthracinus 3.3.3.4 Chironomus plumosus 3.3.3.5 Tanytarsini 3.3.4 Mortality of larvae during pupation 3.4 Discussion 3.4.1 Method discussion 3.4.2 Life cycle 3.4.3 Influence of controlling factors 3.4.4 Larval mortality and chironomid pupae as prey 4. SMALL AND LARGE SCALE DISTRIBUTION ASPECTS AND MIGRATION OF TWO PROCLADIUS AND TWO CHIRONOMUS SPECIES IN THE MESOTROPHIC SAIDENBACH RESERVOIR 4.1 Introduction 4.2 Study area 4.3 Material and methods 4.3.1 Sampling of chironomid pupae 4.3.2 Sampling of chironomid larvae 4.3.3 Large scale distribution 4.3.3.1 Depth gradient of the larval abundance 4.3.3.2 Distribution between different lake areas 4.3.4 Small scale distribution - patchiness 4.3.5 Vertical distribution 4.3.5.1 Residence depth in the sediment 4.3.5.2 Larvae in the water column 4.4 Results 4.4.1 Large scale distribution 4.4.1.1 Depth gradient of the larval abundance 4.4.1.2 Distribution between different lake areas 4.4.2 Small scale distribution - patchiness 4.4.3 Vertical distribution 4.4.3.1 Residence depth in the sediment 4.4.3.2 Larvae in the water column 4.5 Discussion 4.5.1 Large scale distribution 4.5.1.1 Depth gradient of the larval abundance 4.5.1.2 Distribution between different lake areas 4.5.2 Small scale distribution - patchiness 4.5.3 Vertical distribution 4.5.3.1 Residence depth in the sediment 4.5.3.2 Larvae in the water column 5. INVESTIGATIONS ON THE PREFERENCE TEMPERATURE OF C. ANTHRACINUS FROM THE MESOTROPHIC SAIDENBACH RESERVOIR 5.1 Introduction 5.2 Material and methods 5.2.1 Influence of temperature on the timing of pupation 5.2.2 Preference temperature 5.2.3 Locomotory activity of larvae 5.3 Results 5.3.1 Migratory activity of C. anthracinus in the field 5.3.2 Influence of temperature on the timing of pupation 5.3.3 Preference temperature 5.3.4 Locomotory activity of larvae 5.4 Discussion 5.4.1 Influence of temperature on the timing of pupation 5.4.2 Preference temperature 5.4.3 Agitation activity of larvae 6. OVERALL SUMMARY AND FUTURE PROSPECTS 7. REFERENCES EIDESSTATTLICHE ERKLÄRUNG DANKSAGUNG / In the context of the present dissertation an ecological study was performed about chironomids in Saidenbach Reservoir in the Saxony Ore Mountains, Germany during the five years from 2005 to 2010. A preliminary overall species analysis in 2005 showed that three species were most abundant: Procladius crassinervis, P. choreus and Chironomus anthracinus. Additionally, the species C. plumosus was examined because of its close relationship to C. anthracinus. The study is focussed on four subjects, whereby larvae and pupae of the four species were analysed. (1) The elaboration of a reliable method to distinguish the larvae of the two closely related species P. crassinervis and P. choreus on the basis of morphological criteria (imaginal disc development, larval head capsule size and body length) as well as the depth distribution of their pupae was a precondition to the profound analysis of their life cycles. (2) The investigation of the life cycle pattern of the four species was the second focus. The life cycle of the four species was found to be strongly influenced by abiotic conditions such as temperature, oxygen and biovolume of the phytoplankton. (3) The spatial and temporal distribution pattern of the four species was analysed in view of large scale differences over a depth gradient in one transect. Here, in all four species a shift in the mainly settled lake bottom area occurred. The young larvae of C. anthracinus, C. plumosus and P. choreus migrated during maturing and pupation towards shallower areas; P. crassinervis migrated to deeper areas. The distribution differences between two different bays showed that the two Chironomus species had higher densities in the bay with the higher inflow which resulted in a higher phytoplankton standing stock compared to the other species. A small scale distribution pattern analysis focussed on finding out whether the larvae were aggregated or randomly distributed. The vertical distribution analysis examined the swimming behaviour of the larvae. (4) The last aspect was an experimental setup exemplarily driven with C. anthracinus which showed that the migration was stimulated by the proximate factor temperature as pupae preferred warmer temperatures and young larvae colder temperatures. Altogether, the five year study about chironomids in Saidenbach Reservoir pointed out the complex reaction in the behaviour of an important part of the benthic community concerning the life cycle pattern (voltinism, pupation pattern), the changing in abundances (inter-annual and intra-annual) and the large scale and small scale distribution pattern under the rule of the most important environmental factors.:1. GENERAL INTRODUCTION 2. MORPHOLOGICAL DIFFERENTIATION OF TWO PROCLADIUS AND TWO CHIRONOMUS SPECIES IN THE MESOTROPHIC SAIDENBACH RESERVOIR 2.1 Introduction 2.2 Material and methods 2.2.1 Sampling of larvae 2.2.2 Species identification 2.2.3 Differentiation of the Procladius species by means of head capsule size and depth distribution 2.2.4 Other morphological criteria 2.2.5 Development of imaginal discs 2.3. Results 2.3.1 Procladius crassinervis and P. choreus 2.3.2 Chironomus anthracinus and C. plumosus 2.4. Discussion 2.4.1 Method discussion 2.4.2 Head capsule width 2.4.3 Larval growth 3. FIVE - YEAR LIFE CYCLE PATTERN OF TWO PROCLADIUS AND TWO CHIRONOMUS SPECIES IN THE MESOTROPHIC SAIDENBACH RESERVOIR 3.1 Introduction 3.2 Material and methods 3.2.1 Study area 3.2.2 Sampling of chironomid larvae 3.2.3 Sampling of chironomid pupae 3.2.4 Mortality 3.2.5 Abiotic conditions and phytoplankton 3.3 Results 3.3.1 Abiotic conditions and phytoplankton 3.3.1.1 Temperature 3.3.1.2 Oxygen 3.3.1.3 Phytoplankton 3.3.2 Life cycle analysis 3.3.2.1 Composition of instars 3.3.2.2 Procladius crassinervis 3.3.2.3 Procladius choreus 3.3.2.4 Chironomus anthracinus 3.3.2.5 Chironomus plumosus 3.3.2.6 Tanytarsini 3.3.2.7 Other species 3.3.3 Influence of abiotic conditions on pupation and life cycle 3.3.3.1 Procladius crassinervis 3.3.3.2 Procladius choreus 3.3.3.3 Chironomus anthracinus 3.3.3.4 Chironomus plumosus 3.3.3.5 Tanytarsini 3.3.4 Mortality of larvae during pupation 3.4 Discussion 3.4.1 Method discussion 3.4.2 Life cycle 3.4.3 Influence of controlling factors 3.4.4 Larval mortality and chironomid pupae as prey 4. SMALL AND LARGE SCALE DISTRIBUTION ASPECTS AND MIGRATION OF TWO PROCLADIUS AND TWO CHIRONOMUS SPECIES IN THE MESOTROPHIC SAIDENBACH RESERVOIR 4.1 Introduction 4.2 Study area 4.3 Material and methods 4.3.1 Sampling of chironomid pupae 4.3.2 Sampling of chironomid larvae 4.3.3 Large scale distribution 4.3.3.1 Depth gradient of the larval abundance 4.3.3.2 Distribution between different lake areas 4.3.4 Small scale distribution - patchiness 4.3.5 Vertical distribution 4.3.5.1 Residence depth in the sediment 4.3.5.2 Larvae in the water column 4.4 Results 4.4.1 Large scale distribution 4.4.1.1 Depth gradient of the larval abundance 4.4.1.2 Distribution between different lake areas 4.4.2 Small scale distribution - patchiness 4.4.3 Vertical distribution 4.4.3.1 Residence depth in the sediment 4.4.3.2 Larvae in the water column 4.5 Discussion 4.5.1 Large scale distribution 4.5.1.1 Depth gradient of the larval abundance 4.5.1.2 Distribution between different lake areas 4.5.2 Small scale distribution - patchiness 4.5.3 Vertical distribution 4.5.3.1 Residence depth in the sediment 4.5.3.2 Larvae in the water column 5. INVESTIGATIONS ON THE PREFERENCE TEMPERATURE OF C. ANTHRACINUS FROM THE MESOTROPHIC SAIDENBACH RESERVOIR 5.1 Introduction 5.2 Material and methods 5.2.1 Influence of temperature on the timing of pupation 5.2.2 Preference temperature 5.2.3 Locomotory activity of larvae 5.3 Results 5.3.1 Migratory activity of C. anthracinus in the field 5.3.2 Influence of temperature on the timing of pupation 5.3.3 Preference temperature 5.3.4 Locomotory activity of larvae 5.4 Discussion 5.4.1 Influence of temperature on the timing of pupation 5.4.2 Preference temperature 5.4.3 Agitation activity of larvae 6. OVERALL SUMMARY AND FUTURE PROSPECTS 7. REFERENCES EIDESSTATTLICHE ERKLÄRUNG DANKSAGUNG