Products from iron and copper mining are among Sweden’s top exports. However, as the metals are excavated, they often end up in the aquatic environment where they can cause toxicity. To implement the Water Framework Directive (WFD) within the European Union, all member states must classify their waters and set local environmental quality standards (EQS). These EQS are used to set the maximum concentration of a metal allowed in water and can be set both by the Swedish EPA and EU. The WFD EQS are to be based on the bioavailable metal fraction, as compared to the total metal concentration as have been used previously. As a tool in setting EQS, bioavailability models, like the biotic ligand model (BLM), have been proposed. BLMs can calculate toxicity endpoints based on water chemistry and organismal response and these predictions can be used for regional EQS values. However, BLMs are often calibrated toward hard waters with neutral or high pH, containing low concentrations of natural organic material (NOM), a water chemistry most commonly found in the central and southern parts of Europe. The overarching aim of this doctoral thesis was, therefore, to assess the regulatory applicability of Cu BLMs for Swedish conditions. Results from Paper I and II show that for at least 50% of Fennoscandinavian (Sweden, Finland and Norway) freshwater bodies, the models are not fully applicable. This due to crucial model input parameters being outside of the current calibration range of the Cu BLM. Papers II and III further showed that BLM calculated results differed from measured Cu toxicity to daphnids and algae, indicating that model-based EQS will not be protective for these organisms. Moreover, Paper III showed that Al had an impact on Cu speciation and, hence, toxicity. In conclusion, the present thesis shows that several available Cu BLMs are not yet fully applicable for Swedish or Scandinavian freshwater bodies due to incomplete parameterisation of the models.  To improve the applicability of the models, there is a need to calibrate the models for soft freshwater bodies and include Al and NOM properties as input parameters. / Produkter från metallindustrin är bland Sveriges viktigaste exportprodukter. Metallutvinning leder dock till utsläpp som kan hamna i den akvatiska miljön och där orsaka toxicitet. Europeiska Unionens Vattendirektiv syftar till att alla medlemsstater ska klassificera sina vatten och ta fram miljökvalitetsnormer. Dessa normer ska baseras på den biotillgängliga fasen av metaller istället för den totala som tidigare. Biotiska ligand modeller (BLM) har förts fram som verktyg i denna process. BLM kan beräkna utsläppsnivåer för sötvatten baserat på rådande vattenkemi samt vattenorganismers känslighet och ger användaren en specifikt anpassad rekommendation (LC/EC50, NOEC, PNEC o.s.v.). Dock är dessa modeller ofta kalibrerade för en vattenkemi gällande i de centrala och södra delarna av Europa. I Sverige är det vanligt med sura mjuka vatten, vilka har en högre koncentration av biotillgängliga metaller vilka kan orsaka toxicitet. Det övergripande syftet med denna doktorsavhandling var att undersöka hur dagens BLM för koppar (Cu) fungerar för svenska sötvatten. Resultaten från Artikel I och II visar att en stor del av de Fennoskandinaviska vatten som testats faller utanför kalibreringsintervallet för BLM. Vidare visar Artikel III och IV att de testade modellerna inte på ett korrekt sätt kunde uppskatta toxicitet för alger och vattenloppor, vilket innebär att de inte räknar ut skyddande rekommendationer för dessa arter. Det var även tydligt i Artikel IV att aluminium (Al) påverkar kopparspecieringen och genom detta även koppars toxicitet. Sammanfattningsvis visar denna avhandling att flera tillgängliga BLM inte är helt applicerbara i mjuka vatten, ofta p.g.a. opassande intervall för de kemiska parametrarna. För att förbättra tillämpbarheten av BLMs i Sverige krävs det att modellerna dels kalibreras för den rådande vattenkemin och dels att Al och NOMs egenskaper inkluderas.

Methods for determining phosphorus in turbid lake and river water using heating with an autoclave or a microwave and employing alkaline peroxodisulphate digestion have been investigated. Suspensions (up to 100 ugP/L) of two standard reference materials (NIES No. 3 Chlorella and NEES No. 2 Pond Sediment) were used to optimised procedures. Quantitative recoveries of phosphorus were achieved when the final solution to be digested contained 0.045 M potassium peroxodisulphate and 0.04 M sodium hydroxide and solutions were autoclaved at 120°C for 60 min. or microwaved at 450 Watts for 5-10 min. Complete recoveries of phosphorus (99- 103%) from 20 ugP/U 50 ugP/L and 100 ugP/L Chlorella suspensions were obtained using autoclave and microwave heating. For the Pond Sediment suspensions complete recoveries of phosphorus (99-104%) from the 20 ugP/L and 50 ugP/L were obtained using both heating methods. Higher recoveries from the 100 u.gP/L Pond Sediment suspensions were obtained using microwave heating (96±1%) than autoclaving (88±5%). Further analysis of Pond Sediment suspensions using the autoclave heating showed that complete recovery of phosphorus (98±l%) from 60 ngP/L suspensions was achieved with incomplete recoveries (92.3±0.7%, 91�2% and 91�1%) from 70 ugP/L, 80 ugP/L and 90 ug P/L suspensions respectively. Recoveries of phosphorus compounds (orthophosphate and phosphonates) added to distilled water and turbid lake water were near quantitative (91-117%) for both digestion methods. A range of turbid lake and river water (TP = 57-106 ugP/L; Turbidity = 16-200 NTU) were analysed for total phosphorus (TP) using the optimised alkaline peroxodisulphate digestion procedures and the APHA AWWA WPCF, sulphuric acid - nitric acid digestion procedure. No difference in total phosphorus measurements were found between the microwave digestion procedure and the APHA AWWA WPCF, nitric acid - sulphuric acid procedure. The autoclave procedure gave significantly lower recoveries of phosphorus (p<0.01), however, differences were only 2-8%. The effect of freezing (-20�C) water samples without or with the addition of 1% hydrochloric acid before determination of total phosphorus (TP) and total dissolved phosphorus (TDP) was also investigated. No significant change in total phosphorus occurred when samples were stored frozen without the addition of 1% hydrochloric acid in high and low density polyethylene bottles for up to 20 weeks and 2 weeks respectively after collection. Significant changes were found in total dissolved phosphorus when samples were stored frozen without the addition of 1% hydrochloric acid in high and low density polyethylene bottles after 1 day and 2 weeks respectively.

Benthic macroinvertebrate communities in headwater streams influenced by Appalachian coal mining often differ from communities in minimally distrubed streams. Total dissolved solids (TDS) associated with mining have been suggested as stressors to these communities. In studies of such streams conducted to date, both non-TDS stressors and elevated TDS have been present as potential influences on biota. Here the association between dissolved salts and benthic macroinvertebrate community structure was examined using a family-level multimetric index and genus-level taxa sensitivity distributions. Test sites were selected along a gradient of elevated TDS, with non-TDS factors of reference quality. Virginia Stream Condition Index (VASCI) scores were regressed against log-transformed measures of TDS, specific conductance, and sulfate (SO42-) using ordinary least squares and quantile regression techniques. Biological effects, as defined by VASCI scores indicating stressed or severely stressed conditions, were observed with increasing probability from 0% at ≤ 190 mg/L TDS to 100% at ≥ 1,108 mg/L TDS, with 50% probability of effects observed at 422 mg/L TDS. Associations between water quality measures and biological condition were variable, with approximately 48% of the variance explained by TDS. Genus-level analysis using a field sensitivity distribution approach indicated 95% of reference genera were observed at sites with TDS ≤ 281 mg/L, and 80% of genera were observed at sites with TDS ≤ 411 mg/L. This is evidence that TDS, specific conductance, or SO42- can be used to establish dissolved solids levels for streams influenced by Appalachian coal mining above which aquatic life effects are increasingly probable. / Master of Science

Acestrorhynchus Eigenmann& Kennedy, 1903 é um gênero de peixes de água doce, cujas espécies estão distribuídas principalmente na região da América do Sul cis-andina. Conhecidas popularmente como peixe-cachorro, cachorrinho, care´perro ou picuá em Brasil, Venezuela, Colombia e Peru. Caracterizadas por apresentar dentes cônicos e caninos, focinho alongado. São de habito alimentar piscívoro. Algumas espécies são de porte pequeno e outras raramente ultrapassando 40 cm de comprimento. Estão associadas a ambientes lenticos, principalmente lagoas e áreas próximas a margens dos rios. Algumas espécies do gênero realizam migrações reprodutivas de curta distancia, não apresenta cuidado parental. As espécies do gênero Acestrorhynchus têm sido agrupadas principalmente com base no padrão de colorido. Até o presente estudo têm sido reconhecidas 14 espécies válidas: Acestrorhynchus abbreviatus (Cope, 1878); Acestrorhynchus altus Menezes, 1969; Acestrorhynchus britskii Menezes, 1969; Acestrorhynchus falcatus (Bloch, 1794); Acestrorhynchus falcirostris (Cuvier, 1819); Acestrorhynchus grandoculis Menezes & Géry, 1983; Acestrorhynchus heterolepis (Cope, 1878); Acestrorhynchus isalineae Menezes & Géry, 1983; Acestrorhynchus lacustris (Lütken, 1875a); Acestrorhynchus maculipinna Menezes &n Géry, 1983; Acestrorhynchus microlepis (Schomburgk, 1841); Acestrorhynchus minimus Menezes, 1969; Acestrorhynchus nasutus (Eigenmann, 1912); Acestrorhynchus pantaneiro Menezes, 1992. Das quais quatro espécies têm sido reconhecidas no grupo lacustris: Acestrorhynchus abbreviatus (Cope, 1878) da bacia do alto Amazonas e drenagens do rio Madeira; Acestrorhynchus lacustris (Lütken, 1875a) das bacias do alto rio Paraná e rio São Francisco; Acestrorhynchus altus (Menezes, 1969) da bacia do médio e baixo Amazonas e Ilha do Marajó e Acestrorhynchus pantaneiro Menezes, 1992 da bacia do rio Paraguai e da bacia do Prata (rio da Prata, rio Uruguai e baixo Paraná). Estudo de um maior número de exemplares, muitos provenientes de localidades não abrangidas no estudo de Menezes (1992), revelou um aumento da amplitude de variação de dados merísticos e morfométricos das espécies do grupo. Além disso, exemplares depositados recentemente nas coleções revelaram que as distribuições geográficas das outras especies de Acestrorhynchus são mais amplas do que conhecida. Foram analisados 630 exemplares do grupo lacustris, dos quais 508 tiveram dados merísticos e morfométricos enquanto que para a atualização de informação geográfica das demais espécies do gênero foram analisados 3048 exemplares. Exemplares analisados neste estudo, incluindo exemplares de localidades não amostradas na ultima revisão do grupo, mostrou que as características utilizadas como diagnosticas para as espécies do grupo lacustris: escamas ao redor do pedúnculo caudal, escamas acima da linha lateral, escamas abaixo da linha lateral, comprimento da nadadeira peitoral, passando ou quase sempre ultrapassando a origem da pélvica e a relação de tamanho da mancha caudal, apresentam sobreposição nas amplitudes de variação dessas contagens por tanto não foram corroboradas neste estudo. São reconhecidas duas espécies válidas para o grupo lacustris: Acestrorhynchus abbreviatus (Cope, 1878) e Acestrorhynchus lacustris (Lükten, 1875a), sendo Acestrorhynchus altus e Acestrorhynchus pantaneiro, sinônimos junior de Acestrorhynchus abbreviatus com novas localidades de ocorrência. / Acestrorhynchus Eigenmann & Kennedy, 1903 is a genus of fresh water fishes geographically distributed through South America, specially east from the Andes. The species from this genus are commonly known as \"peixe-cachorro\", \"cachorrinho\", \"care´perro\" or \"picuá\" in Brazil, Venezuela, Colombia and Peru. Species in this genus are characterized by conic and canine teeth and prolonged snout. The food habit is piscivorous. Some species have small bodies and other rarely grow over 40 cm in length. They are associated with lentic habitats, mainly lagoons and areas close to river margins. Some species of the genus migrate short distances in order to reproduce and do not exibit parental care. The color pattern has been the main character to group species from the Acestrorhynchus genus. Until the present study, there were 14 valid species: Acestrorhynchus abbreviates (Cope, 1878); Acestrorhynchus altus Menezes, 1969; Acestrorhynchus britskii Menezes, 1969; Acestrorhynchus falcatus (Bloch, 1794); Acestrorhynchus falcirostris (Cuvier, 1819); Acestrorhynchus grandoculis Menezes & Géry, 1983; Acestrorhynchus heterolepis (Cope, 1878); Acestrorhynchus isalineae Menezes & Géry, 1983; Acestrorhynchus lacustris (Lütken, 1875a); Acestrorhynchus maculipinna Menezes &n Géry, 1983; Acestrorhynchus microlepis (Schomburgk, 1841); Acestrorhynchus minimus Menezes, 1969; Acestrorhynchus nasutus (Eigenmann, 1912); Acestrorhynchus pantaneiro Menezes, 1992. Of these species, four have been recognized in the lacustris group: Acestrorhynchus abbreviates (Cope, 1878) from the upper Amazon basin and Madeira river drainages; Acestrorhynchus lacustris (Lütken, 1875a) from basins of upper Paraná river and São Francisco river; Acestrorhynchus altus (Menezes, 1969) from middle and lower Amazon basins and the Marajó island and Acestrorhynchus pantaneiro Menezes, 1992 from Paraguay and the Prata river basins (Prata river, Uruguay river and lower Paraná river). The number of specimens studied in this work is greater than what was studied in Menezes (1992) and most of the examined specimes come from localities not available to this later work. The analysis of these data revealed greater amplitudes in meristic and morphometric characteristics in the lacustris species. Besides that, the new studied specimens also revealed a wider geographic distribution for Acestrorhynchus species, even for those not in the lacustris group. In this work 630 lacustris specimens were examined, of which, 508 had meristic and morphometric data recorded and analyzed. In order to update the geographic distribution of other species from Acestrorhynchus genus, locations from 3048 specimens were studied. The analysis of the specimens in this study, including individuals from localities not sampled in the last taxonomic revision of the species of Acestrorhrynchus of the lacustris group, revealed that the characteristics that are used as diagnostic for the species of the lacustris group: a) number of scales around the caudal peduncle, b) number of scales above the lateral line, c) number of scales below the lateral line, d) length of pectoral fin almost always going beyond the origin of the pelvic fin and e) the size of the caudal spot, display overlap between the species of the lacustris group. The result of this study recognize two valid species for lacustris group: Acestrorhynchus abbreviates (Cope, 1878) and Acestrorhynchus lacustris (Lükten, 1875a), being Acestrorhynchus altus and Acestrorhynchus pantaneiro, junior synonyms of Acestrorhynchus abbreviates in new occurrence localities.

La diversité des très petits eucaryotes (<5 µm) a essentiellement été étudiée par des méthodes moléculaires dans les océans ou de grands lacs. La diversité dans les écosystèmes d'eau douce peu profonds reste très peu explorée, bien que ces systèmes soient très nombreux et écologiquement importants en régions tempérées. Dans ce travail, nous avons voulu explorer la diversité et certains aspects de l'écologie des micro-organismes eucaryotes dans ce type d'écosystèmes, à l'aide de méthodes moléculaires ciblant l'ADNr 18S de cellules planctoniques de surface, dans la fraction de taille théorique 0,2-5 µm. Nous nous sommes d'abord concentrés sur les haptophytes, un groupe important en milieu marin mais beaucoup moins bien connu en eaux douces. Nous avons exploré leur diversité à l'aide d'amorces spécifiques pour amplifier les gènes des ARNr 18S du groupe suivi du clonage / séquençage Sanger de ces marqueurs, dans 17 écosystèmes continentaux et 2 colonnes d'eau marines pour comparer la diversité dans différents milieux, ainsi qu'à l'aide du pyroséquençage de ce même marqueur dans 4 mares et 1 ru au cours d'un suivi mensuel sur 2 ans. La diversité des haptophytes était moindre en eau douce qu'en milieu marin, mais nous avons pu y détecter un nouveau groupe, divergeant au sein des Isochrysidales, présentant une saisonnalité marquée. Les phylotypes d'eau douce étaient majoritairement distincts de ceux détectés en milieu marin, et ont confirmé l'existence de plusieurs transitions marin/eau douce dans l'histoire des haptophytes. Dans un second temps, nous avons exploré par pyroséquençage 454 des ADNr 18S la diversité des micro-organismes eucaryotes dans 4 mares et 1 ru, échantillonnés au printemps, et différant par leur taille, leur forme et leur environnement proche. Nous avons détecté une grande diversité dans chaque système étudié, avec des séquences affiliées à tous les supergroupes reconnus (Archaeplastida, Stramenopiles, Alveolata, Rhizaria, Excavata, Amoebozoa et Opisthokonta), ainsi qu'à des taxa de position phylogénétique mal résolue (i.e. Cryptophyta, Haptophyta, Centroheliozoa Katablepharida). Notamment, certaines OTU étaient affiliées au groupe MAST-3 (MArine STramenopiles) jusque-là considéré comme exclusivement marin. Les communautés de petits eucaryotes étaient différentes dans chacun des écosystèmes ; ces différences ne corrélaient pas avec les distances géographiques entre sites (test de Mantel), et des analyses multivariées n'ont pas mis en évidence de relation claire entre la distribution d'un groupe et un paramètre environnemental. Par la suite, nous avons suivi la diversité des eucaryotes microbiens sur 2 ans dans les mêmes 5 écosystèmes. Nous avons collecté des échantillons de plancton et mesuré différents paramètres physico-chimiques chaque mois, sauf pour 2 des écosystèmes lorsqu'ils étaient à sec. La diversité détectée sur 2 ans était bien plus grande que celle identifiée lors de l'étude ponctuelle. Cryptophytes, ciliés, chrysophytes et champignons stricto sensu étaient globalement les plus abondants. La composition et la structure des communautés différaient d'un écosystème à l'autre sur l'ensemble du suivi. Ces communautés étaient très dynamiques, et montraient une saisonnalité claire. La distribution spatio-temporelle des champignons sensu stricto était clairement corrélée aux hautes valeurs de conductivité. Enfin, nous avons décrit la dynamique des communautés de petits eucaryotes dans l'une des mares et le ru lors d'épisodes de sécheresse. Nous avons collecté du sédiment dans le lit asséché des écosystèmes lors des sécheresses, et du plancton le reste du temps. Les communautés du sédiment présentaient une signature différente des assemblages planctoniques. Ces derniers montraient une résilience élevée, et retrouvaient une signature planctonique moins d'un mois après que les écosystèmes soient de nouveau en eau. / The diversity of very small eukaryotes (<5 µm) has mainly been studied by molecular methods in marine systems or in large lakes. However, that of small shallow systems remains practically unexplored, despite the fact that these systems are extensive and ecologically important in temperate regions. We thus aimed at describing the diversity and community composition of small eukaryotes in shallow freshwater systems, using molecular methods targeting the 18S rRNA gene of planktonic cells in the 0.2-5 µm size range. We first focused on haptophytes, an important group in marine environments but much less known in freshwaters. We explored their diversity using newly designed specific primers to amplify haptophyte 18S rRNA genes, followed by their subsequent cloning and Sanger sequencing in seventeen continental ecosystems and in two marine water columns to allow comparisons between different environments, as well as using 454-pyrosequencing in 4 ponds and one brook during a 2-years monthly survey. Even if freshwater haptophytes were less diverse than marine lineages, we revealed the presence of a divergent lineage belonging to the Isochrysidales never recorded so far, which presented a marked seasonality. Freshwater phylotypes were usually distinct from their marine counterparts, and confirmed the occurrence of multiple marine–freshwater transitions in haptophyte evolution. In a second step, we explored the microbial eukaryote diversity in 5 distinct shallow ecosystems sampled at spring and that differ in size, shape and surrounding environment, by 454-pyrosequencing their 18S rDNA. Diversity was high in the studied systems, with sequences affiliated to the 7 recognized eukaryotic supergroups (Archaeplastida, Stramenopiles, Alveolata, Rhizaria, Excavata, Amoebozoa and Opisthokonta) as well as groups of unresolved phylogenetic position including, among others, Cryptophyta, Haptophyta, Centroheliozoa or Katablepharida. Especially, we detected OTUs affiliated to the previously thought exclusively marine lineage MAST-3 (MArine STramenopiles), and potentially to other MAST groups with no known representative from freshwaters. Small eukaryote community structures were different in the five ecosystems. Differences in community compositions did not correlate with geographical distances (Mantel test), and multivariate statistical analyses did not reveal clear relationships between any group distribution and specific environmental parameters. Then, we conducted a 2-years survey of eukaryotic micro-organisms diversity in the same 5 small ecosystems. To do so, we collected plankton and measured several physical and chemical parameters on a monthly basis, except for two systems when they were totally dry. The total diversity encountered during the 24 months was much broader than that identified in the previous snapshot study. The most abundant detected groups were Cryptophytes, Ciliates, Chrysophytes and Fungi sensu stricto. Community structures and compositions were different in the five systems along the two years. In all systems, communities were highly dynamic, and revealed a marked seasonality, notably with summer and winter communities being always distinct. Multivariate statistical analyses were used to analyze simultaneously physico-chemical data and community compositions. The clearest correlation associated fungi distribution and high conductivity. Finally, we described the dynamics of small-eukaryote communities in a pond and a brook through drought events. We collected sediment on the system beds when they were dry, and plankton the rest of time. Communities in the sediment and in the water presented distinct signatures. Surface water communities presented (a high) resilience, and recovered a planktonic signature within a month after the systems were filled up again with water.

L’oxyde nitreux (N2O), un puissant gaz à effet de serre (GES) ayant plus de 300 fois le potentiel de réchauffement du dioxyde de carbone (CO2), est produit par des processus microbiens du cycle de l’azote (N). Bien que les eaux de surface continentales soient reconnues comme des sites actifs de transformations de l’azote, leur intégration dans les budgets globaux de N2O comporte de nombreuses incertitudes, dont l’absence des lacs dans ces modèles. Le biome boréal est caractérisé par une des plus grandes densités d’eaux douces au monde, pourtant aucune évaluation exhaustive des émissions aquatiques de N2O n’a à date été conduite dans cette région. Dans la présente étude, nous avons mesuré les concentrations de N2O à travers une large gamme de lacs, rivières, et étangs, dans quatre régions boréales du Québec (Canada), et nous avons calculé les flux eau-air résultants. Les flux nets fluctuent entre -23.1 et 177.9 μmol m-2 J-1, avec une grande variabilité inter-système, inter-régionale, et saisonnière. Étonnamment, 40% des systèmes échantillonnés agissaient en tant que puits de N2O durant l’été, et le réseau d’eaux de surfaces d’une des régions était un net consommateur de N2O. Les concentrations maximales de N2O ont été mesurées en hiver dû à l’accumulation de ce gaz sous la glace. Nous avons estimé que l’émission qui en résulte lors de la fonte des glaces représente 20% des émissions annuelles des eaux douces. Parmi les types d’eaux douces échantillonnées, les lacs sont les principaux responsables du flux aquatique net (jusqu’à 90%), et doivent donc être intégrés dans les budgets globaux de N2O. En se basant sur les données empiriques de la littérature, nous avons éstimé l’émission globale de N2O des eaux douces à 0.78 Tg N (N2O) an-1. Ce chiffre est influencé par les émissions des régions de hautes latitudes (tel que le biome boréal) dont les flux nets varient de positif à négatif constituant -9 à 27 % du total. / Nitrous oxide (N2O), a potent greenhouse gas with over 300 times the global warming potential of carbon dioxide (CO2), is produced during microbial nitrogen (N) cycling (Trogler 1999). Inland waters, known as active sites of N processing (Seitzinger et al. 2006., Harrison et al. 2008), are nevertheless poorly characterized in recent global N2O budgets (Nevison 2000, Intergovernmental Panel on Climate 2006), especially considering the absence of an estimate for lakes emissions. Although the boreal biome holds the highest density of freshwater on earth (Lehner and Döll 2004), no comprehensive evaluation of N2O emissions from boreal aquatic systems has ever been conducted. In this study, we measured N2O concentrations across a wide range of rivers, lakes, and ponds in four distinct boreal regions of Québec (Canada), and derived water surface-atmosphere N2O fluxes. Net fluxes ranged from -23.1 to 177.9 μmol m-2 d-1, with a large degree of variability across sampled systems, regions, and seasons. Over 40% of the 322 systems sampled acted as N2O sinks during the summer, with one region’s aquatic network being an overall net atmospheric N2O consumer. Seasonally, maximum N2O concentrations were measured during winter due to gas accumulation under the ice, resulting in an outgassing at ice thaw that accounts for approximately 20% of annual flux. Lakes were major drivers of the net freshwater regional flux (up to 90%), and must therefore be integrated in global aquatic N2O budgets. Based on empirical literature data, we estimated global freshwater N2O emissions to be 0.78 Tg N (N2O) yr-1. This number is subtantially influenced by fluxes from high latitude regions (including the boreal biome) which, being extremely variable, may contribute from -9 to 27 % of the total.

La presente tesis doctoral aborda distintas estrategias y metodologías en el contexto de la conservación de la biodiversidad de ecosistemas de aguas continentales en el Sureste Ibérico, utilizando inventarios de coleópteros acuáticos. En primer lugar, se propone un método para evaluar la vulnerabilidad de especies y para asignar prioridades de conservación a especies y poblaciones de insectos. A continuación, se compara la eficacia de diferentes métodos de selección de áreas y se estudia el rendimiento de las áreas protegidas en el contexto de la conservación de la biodiversidad de sistemas acuáticos. Por otro lado, se testa el comportamiento de tres índices de diferenciación taxonómica con relación a los niveles de impacto antrópico en aguas continentales. Finalmente, se estudia la variación genética y la filogeografía de Ochthebius glaber, un escarabajo acuático raro y amenazado endémico de arroyos hipersalinos del sur y sureste de la Península Ibérica.