Esta pesquisa teve o objetivo principal de caracterizar a estrutura da comunidade fitoplanctônica, no espaço e no tempo e relacioná-la às variações climatológicas e hidrológicas, em sistema de áreas alagáveis, da planície de inundação do rio Jacupiranguinha. As coletas foram realizadas durante quatro épocas do ano, em 3 dias alternados e 11 estações de amostragem (estações 1 e 2, no rio Jacupiranguinha; estação 3, no córrego Serrana e estações 4 a 11, no sistema de áreas alagáveis). Esta pesquisa contemplou a análise de variáveis climatológicas (precipitação e radiação solar fotossinteticamente ativa, por exemplo) e hidrológicas como, formas de carbono, sólidos em suspensão, nutrientes, biovolume, freqüência específica, dominância e diversidade específicas da comunidade fitoplanctônica.O sistema de áreas alagáveis estudado foi regulado pelo regime hidrológico anual do rio Jacupiranguinha. Em período chuvoso, os pulsos de inundação foram responsáveis por intensas modificações nestes ambientes. A entrada de sedimento e o aumento dos níveis hidrométricos estão entre os distúrbios ocasionados pela entrada de água lateral. A comunidade fitoplanctônica respondeu a estas variações com suas estratégias de sobrevivência. Uma das características importantes observadas neste estudo foi que nas estações próximas ao rio, as maiores concentrações de sólidos suspensos coincidiram com o período chuvoso. Na estação 4, próxima à estação 2 (rio Jacupiranguinha), as maiores concentrações de sólidos suspensos inorgânicos (168,0 mg/L) e orgânicos (150,0 mg/L) foram verificadas neste período. O mesmo pode ser observado na estação 11, próxima a outro acesso ao rio Jacupiranguinha (68,0 mg/L, sólidos suspensos inorgânicos e 22,0 mg/L, sólidos suspensos orgânicos). O índice de dominância atingiu o valor máximo (1,0) em várias estações e houve semelhança entre as comunidades fitoplanctônicas do rio Jacupiranguinha e das estações próximas ao rio, quando as concentrações de sólidos suspensos foram maiores. As espécies dominantes, em época de cheia, no sistema de áreas alagáveis foram Cyanobium parvum (cianobactéria) e Trachelomonas volvocina (euglenofícea). A comunidade fitoplanctônica também apresentou variação espacial e temporal, com predomínio de Cyanobacteria em três das quatro épocas do ano, principalmente, nas estações localizadas dentro do sistema de áreas alagáveis. A classe Euglenophyceae se destacou, assim como as Cyanobacteria, por serem adaptadas a sobreviverem em ambientes com baixa penetração de luz. Bacillariophyceae estiveram presentes, principalmente, nas estações com maior mistura (rio Jacupiranguinha - estações 1 e 2). Os resultados sugerem que as alterações hidrológicas provocadas pelos pulsos de inundação, como o aumento na concentração de sólidos suspensos, diminuição da zona eufótica, diluição da água, entre outros; e a densa cobertura de macrófitas aquáticas sobre algumas estações, tendo como conseqüência a redução da penetração de radiação solar fotossinteticamente ativa na água, foram os principais fatores determinantes da estrutura da comunidade fitoplanctônica deste sistema. / This study aimed at characterizing the spatial and temporal structure of the phytoplanktonic community and relating them to climatological and hydrological variations in the floodplain of Jacupiranguinha river. The samples were taken four times in the year, once in each season, on 3 alternating days at 11 sample stations, two of which are positioned in the river itself (stations 1 and 2), one in the stream Serrana (station 3) and eight distributed in the mentioned wetland (stations 4 to 11). This research considered the analysis of the climatological variables, e.g., photosynthetically active solar radiation and rain, as well as the hydrological ones, as there are types of carbon, suspended particles, nutrients, biovolume, specific frequency, dominance and specific diversity of phytoplanktonic community. The respective wetland was controlled by the yearly hydrological cycle of Jacupiranguinha river. In rainy season, this environment suffered intensive modifications caused by frequent flooding. Lateral water currents are responsible for incoming sediments and the increase of water levels. The response of the phytoplanktonic community to these changes was found in its survival strategies, i.e. flagellum and reduction of cellular density. The fact that the sample stations close to the river showed the highest concentrations of suspended solids in the rainy season was one of the most important points observed in this study. The highest concentrations of inorganic suspended solids (168,0 mg/L) and organic suspended solids (150 mg/L) were found in this period at station 4, close to station 2. The same phenomenon could be seen at station 11, close to the other access to the Jacupiranguinha river (68 mg/L of inorganic suspended solids and 22 mg/L of organic suspended solids). The dominance index reached its highest value (1,0) at different stations. In general, there has been a similarity between the phytoplanktonic communities of Jacupiranguinha river and the stations close to it at the periods which concentrations of suspended solids were the highest. In the studied wetland, predominant species, during rainy season, were Cyanobium parvum (Cyanobacteria) and Trachelomonas volvocina (Euglenophyceae). The phytoplanktonic community also presented spatial and temporal variation, with predominance of Cyanobacteria in three of the four seasons and mainly at the stations inside the wetland system. Euglenophyceae stood out as well as the one of Cyanobateria due to their adaptation and survival in low-light environments. Bacillariophyceae were present mainly at the stations 1 and 2 which showed a higher stir of water. The results suggest that the hydrological alterations provoked by the flooding were the principal determining factors of the phytoplanktonic community of the system. These factors were e.g. an increase in suspended solids concentrations, decrease of euphotic zone and dilution of water. Other effects could be found in the dense cover of aquatic macrophytes on some stations, resulting in reduction of photosynthesis caused by less penetration of solar radiation.

Cumáceos são crustáceos peracáridos cosmopolitas que se distribuem desde a zona entre-marés até os fundos abissais. Habitam fundos arenosos e lodosos e eventualmente são encontrados no ambiente pelagial. Apesar de sua importância na dieta de diversos organismos, e de serem considerados bons indicadores ambientais, poucos estudos ecológicos foram realizados com o grupo no Brasil, não havendo uma avaliação do papel que desempenham na estruturação e funcionamento do ecossistema bêntico. O presente estudo tem por objetivo descrever a composição e a distribuição espaço-temporal das espécies de Cumacea, investigar a existência de comunidades e sua estrutura, identificar os principais fatores responsáveis pelos agrupamentos encontrados e avaliar o efeito das mudanças sazonais da estrutura oceanográfica sobre os descritores utilizados. Para tanto, foi realizada uma campanha oceanográfica no inverno de 2005 e outra no verão de 2006, em uma grade de 21 estações situadas na plataforma continental sudeste, entre São Sebastião e Peruíbe, amostradas por meio de Box Corer e Draga. Os resultados mostraram a presença de 31 espécies de Cumacea em toda a área, sendo 24 no inverno e 28 no verão. Os valores mais elevados de densidade, diversidade e riqueza situaram-se nas estações próximas a isóbata de 50m em ambas as campanhas, podendo ser atribuídos à presença da Água Central do Atlântico Sul sobre essas áreas, uma vez que ela promove intensa eutrofização da coluna da água e também confere maior estabilidade ambiental devido a formação de termoclina na coluna da água. Os resultados mostraram ainda que a profundidade e as características granulométricas do sedimento foram os principais fatores determinantes da composição e distribuição das comunidades de Cumacea. Desta forma foram evidenciadas três faixas de profundidade paralelas à costa com comportamento oceanográfico próprio: zona rasa, zona intermediária e zona profunda, cada qual apresentando espécies características e organizadas em estruturas ecologicamente distintas, caracterizando comunidades. A utilização de diferentes aparelhos, como Box Corer e Draga, permitiu complementação amostral da fauna, propiciando um conjunto de informações abrangentes e que permitiu a realização de um estudo mais robusto. / Cumaceans are Peracarid crustaceans distributed worldwide, occurring from intertidal zone to abyssal plains. They inhabit sandy and muddy bottoms, and are eventually found in the pelagic environment. Despite their importance as food for many organisms and their role as environmental indicators, few ecological studies have been conducted in Brazil up to now, and there are no efforts for understanding their role in structuring benthic communities. The aim of the present study is to describe the composition and spatio-temporal distribution of the cumaceans species in the continental shelf offshore of Santos, to investigate the existence and strucuture of ecological communities and the main factors responsible for their functioning, trying to assess the effects of the oceanographic changes upon the community descriptors. The samples were obtained on 21 stations placed in the southeastern continental shelf, between São Sebastião and Peruíbe, in winter 2005 and summer 2006, by means of a 0,09m2 box corer and a rectangular dredge. The results showed the presence of 31 species of cumaceans in the whole area, being 24 in winter and 28 in summer. Higher values of density, diversity and richness obtained in stations near the 50m isobath in both campaigns can may be attributed to the South Atlantic Central Water presence on these areas, since it promotes intense eutrophication of the water column and environmental stability by means of the stablishment of a sub-superficial thermocline. The present study also showed that depth and sediment grain size were the main factors determining the composition and distribution of the cumacean communities. Three zones parallel to the coast with distinct depth ranges and oceanographic features were observed: shallow zone, intermediate zone and deeper zone, each one presenting characteristic species and ecologically structurated in different ways. The use of different sampling gears, as Box corer and dredge, allowed the complementation of data and enlarged the data set adding robustness to the study.

Esta pesquisa teve o objetivo principal de caracterizar a estrutura da comunidade fitoplanctônica, no espaço e no tempo e relacioná-la às variações climatológicas e hidrológicas, em sistema de áreas alagáveis, da planície de inundação do rio Jacupiranguinha. As coletas foram realizadas durante quatro épocas do ano, em 3 dias alternados e 11 estações de amostragem (estações 1 e 2, no rio Jacupiranguinha; estação 3, no córrego Serrana e estações 4 a 11, no sistema de áreas alagáveis). Esta pesquisa contemplou a análise de variáveis climatológicas (precipitação e radiação solar fotossinteticamente ativa, por exemplo) e hidrológicas como, formas de carbono, sólidos em suspensão, nutrientes, biovolume, freqüência específica, dominância e diversidade específicas da comunidade fitoplanctônica.O sistema de áreas alagáveis estudado foi regulado pelo regime hidrológico anual do rio Jacupiranguinha. Em período chuvoso, os pulsos de inundação foram responsáveis por intensas modificações nestes ambientes. A entrada de sedimento e o aumento dos níveis hidrométricos estão entre os distúrbios ocasionados pela entrada de água lateral. A comunidade fitoplanctônica respondeu a estas variações com suas estratégias de sobrevivência. Uma das características importantes observadas neste estudo foi que nas estações próximas ao rio, as maiores concentrações de sólidos suspensos coincidiram com o período chuvoso. Na estação 4, próxima à estação 2 (rio Jacupiranguinha), as maiores concentrações de sólidos suspensos inorgânicos (168,0 mg/L) e orgânicos (150,0 mg/L) foram verificadas neste período. O mesmo pode ser observado na estação 11, próxima a outro acesso ao rio Jacupiranguinha (68,0 mg/L, sólidos suspensos inorgânicos e 22,0 mg/L, sólidos suspensos orgânicos). O índice de dominância atingiu o valor máximo (1,0) em várias estações e houve semelhança entre as comunidades fitoplanctônicas do rio Jacupiranguinha e das estações próximas ao rio, quando as concentrações de sólidos suspensos foram maiores. As espécies dominantes, em época de cheia, no sistema de áreas alagáveis foram Cyanobium parvum (cianobactéria) e Trachelomonas volvocina (euglenofícea). A comunidade fitoplanctônica também apresentou variação espacial e temporal, com predomínio de Cyanobacteria em três das quatro épocas do ano, principalmente, nas estações localizadas dentro do sistema de áreas alagáveis. A classe Euglenophyceae se destacou, assim como as Cyanobacteria, por serem adaptadas a sobreviverem em ambientes com baixa penetração de luz. Bacillariophyceae estiveram presentes, principalmente, nas estações com maior mistura (rio Jacupiranguinha - estações 1 e 2). Os resultados sugerem que as alterações hidrológicas provocadas pelos pulsos de inundação, como o aumento na concentração de sólidos suspensos, diminuição da zona eufótica, diluição da água, entre outros; e a densa cobertura de macrófitas aquáticas sobre algumas estações, tendo como conseqüência a redução da penetração de radiação solar fotossinteticamente ativa na água, foram os principais fatores determinantes da estrutura da comunidade fitoplanctônica deste sistema. / This study aimed at characterizing the spatial and temporal structure of the phytoplanktonic community and relating them to climatological and hydrological variations in the floodplain of Jacupiranguinha river. The samples were taken four times in the year, once in each season, on 3 alternating days at 11 sample stations, two of which are positioned in the river itself (stations 1 and 2), one in the stream Serrana (station 3) and eight distributed in the mentioned wetland (stations 4 to 11). This research considered the analysis of the climatological variables, e.g., photosynthetically active solar radiation and rain, as well as the hydrological ones, as there are types of carbon, suspended particles, nutrients, biovolume, specific frequency, dominance and specific diversity of phytoplanktonic community. The respective wetland was controlled by the yearly hydrological cycle of Jacupiranguinha river. In rainy season, this environment suffered intensive modifications caused by frequent flooding. Lateral water currents are responsible for incoming sediments and the increase of water levels. The response of the phytoplanktonic community to these changes was found in its survival strategies, i.e. flagellum and reduction of cellular density. The fact that the sample stations close to the river showed the highest concentrations of suspended solids in the rainy season was one of the most important points observed in this study. The highest concentrations of inorganic suspended solids (168,0 mg/L) and organic suspended solids (150 mg/L) were found in this period at station 4, close to station 2. The same phenomenon could be seen at station 11, close to the other access to the Jacupiranguinha river (68 mg/L of inorganic suspended solids and 22 mg/L of organic suspended solids). The dominance index reached its highest value (1,0) at different stations. In general, there has been a similarity between the phytoplanktonic communities of Jacupiranguinha river and the stations close to it at the periods which concentrations of suspended solids were the highest. In the studied wetland, predominant species, during rainy season, were Cyanobium parvum (Cyanobacteria) and Trachelomonas volvocina (Euglenophyceae). The phytoplanktonic community also presented spatial and temporal variation, with predominance of Cyanobacteria in three of the four seasons and mainly at the stations inside the wetland system. Euglenophyceae stood out as well as the one of Cyanobateria due to their adaptation and survival in low-light environments. Bacillariophyceae were present mainly at the stations 1 and 2 which showed a higher stir of water. The results suggest that the hydrological alterations provoked by the flooding were the principal determining factors of the phytoplanktonic community of the system. These factors were e.g. an increase in suspended solids concentrations, decrease of euphotic zone and dilution of water. Other effects could be found in the dense cover of aquatic macrophytes on some stations, resulting in reduction of photosynthesis caused by less penetration of solar radiation.

Environmental gradients structure ichthyofaunal communities longitudinally along river networks via the selective filtering of species’ traits. In many instances, these environmental influences have created distinct zones of co-occurring fish species. Zonation studies have most often been conducted with taxonomic data (species x site matrices), but the increasing availability of functional trait data creates an opportunity to build more rigorous understanding of species’ co-occurrence patterns. Notably, zonation studies that use taxonomic data may not reveal the same patterns as studies based on trait data. In this study, we tested for distinct ichthyofaunal zonation in James River Basin, VA using a combination of historical (1950-1987) and contemporary fish occurrence records (1986-2016) that were aggregated within 12-digit hydrologic units (HU). Zonation tests were performed separately for taxonomic data and functional trait data, using a combination of non-metric multidimensional scaling and k-means cluster analysis. We detected three distinct taxonomic zones and three functional trait zones within the James River Basin. In addition, through identifying that taxonomic dissimilarity between HUs was strongly correlated with functional dissimilarity, these zonation patterns were determined to not be significantly different.

Orientador: Denise de Campos Bicudo / Banca: Andréa Tucci / Banca: Liliana Rodrigues / Banca: Raoul Henry / Banca: Orlando Necchi Junior / Resumo: O estudo visou (a) identificar o nutriente limitante ao desenvolvimento do perifiton em escala sazonal no Lago das Ninfeias, (b) avaliar os principais atributos da comunidade indicadores desta limitacao, (c) caracterizar as principais alteracoes estruturais da comunidade de algas perifiticas frente ao enriquecimento artificial por nitrogenio e/ou fosforo e hierarquizar os fatores direcionadores dessas modificacoes. Foram realizados enriquecimentos isolados e combinado por N e P em represa rasa mesotrofica em quatro epocas do ano (primavera, verao, outono e inverno). Quatro tratamentos foram delineados utilizando substrato difusor de nutrientes (copos de poliestireno, preenchidos com solucao Agar e nutrientes . controle: sem adicao de nutrientes; N+: 0,75 M; P+: 0,05 M; NP+: adicao combinada dos dois sais, razao molar N:P = 15). A abertura dos copos foi revestida com malha de 20 um como substrato para o perifiton. Coletas foram realizadas aos 15o, 20o, 25o e 30o dias de colonizacao. A maior variabilidade dos dados limnologicos abioticos foi atribuida ao tipo de tratamento, seguida pela escala anual. A ACP indicou forte associacao entre a adicao de fosforo e, principalmente, adicao combinada com as maiores densidades de algas, clorofila-a e conteudo de fosforo do perifiton. O fosforo foi o nutriente limitante ao longo do ano e, dependendo do atributo, foi considerado como nutriente limitante, limitante primario ou co-limitado pelo nitrogenio. Exceto a massa organica, os demais atributos do perifiton foram bons indicadores da limitacao e a composicao quimica do perifiton foi decisiva na definicao desta limitacao. Foram encontrados 203 taxons, com maior representacao da classe Chlorophyceae. A riqueza especifica variou de 33 a 66 e sofreu maior influencia da epoca do ano / Abstract: Study aimed at (a) identifying the nutrient limitation to the development of algal periphyton in a seasonal scale at the Ninfeias Reservoir; (b) evaluating the main indicator community attributes of nutrient limitation; and (c) characterizing the main structural modifications underwent by the algal periphytic community caused by the artificial enrichment by nitrogen and/or phosphorus, as well as ranking the driven factors responsible for such modifications. Isolate and combined enrichments were carried out in a shallow, mesotrophic reservoir during four occasions (spring, summer, fall, and winter). Four treatments were designed using diffusing substrate (polystyrene vials filled with agar solution and nutrients . control: no nutrient addition; N+: 0.75 M; P+: 0.05 M; NP+: combined addition of N and P, molar ratio N:P = 15). Vial mouth was covered with a 20 um mesh cloth for periphyton colonization. Samplings were performed on the 15th, 20th, 25th, and 30th colonization days. The greatest abiotic limnological data variation was related to the kind of treatment, followed by the annual scale. PCA indicated a strong association between P and mainly combined P and N addition with the highest algal densities, chlorophyll a, and the P periphyton contents. Phosphorus was the limiting nutrient over the year, and depending on the periphyton attribute, it was either the only limiting nutrient, the primary limiting one, or colimited with N. Except for the organic mass, the remaining periphyton attributes were good nutrient limitation indicators, and periphyton chemical composition was conclusive in defining limitation. Two hundred and three taxa were identified, Chlorophyceae being the dominant algal class. Species richness varied from 33 to 66, being influenced mostly by the time of the year / Doutor

The goal of this research was to determine the relative quality of near shore marine areas by investigating their influence on Haemulidae community structure, distribution pattern, condition, and growth. Habitat was defined at the small spatial scale of individual habitat types such as seagrass beds, mangroves and coral reefs, and at the broader spatial scale of the interconnection of these individual habitat types within a mosaic (IHM). Ten spatial, biotic and abiotic parameters (percentage coverage of sand, mangroves, hard substrate, and seagrass, turbidity, pH, salinity, temperature, average depth, and predator density) were investigated. These environmental characteristics acted as proxies for the quality of IHMs. The major findings of the research were: (1) IHMs and discrete habitat types in tropical marine systems are not always equal in quality. Further, the highest quality IHMs/discrete habitat types have the critical resources whether spatial, abiotic or biotic, at the optimum levels needed by organisms to carry out their critical life functions; (2) IHMs of the highest quality contain all the discrete habitat types needed by organisms to carry out their life processes in a spatial arrangement that maximizes energy savings; (3) IHMs can be of high quality in the absence of one habitat type, if this habitat type is replaced by another that can take on its ecological role; and (4) the percentage cover of hard substratum and seagrass, temperature, and predator density have a big impact on Haemulidae distribution pattern, community structure, condition and growth. In addition, this research highlighted some of many characteristics of benthic habitats such as type and configuration that should be included in the design of Marine Protected Areas for the effective management of fisheries resources. Effective Marine Protected Areas should have (1) large overall area with benthic habitat types of high quality; (2) spatial configurations with short distances (corridors) between habitat types; (3) spatial arrangements that place all individual habitat types in connection with all other habitat types so that energy expenditure in moving among habitat types is reduced; (4) habitats with high structural complexity; and (5) the inclusion of all the habitat types needed by focal organisms to carry out their life processes, or surrogate habitat types that can take on the role of ones that are absent.

Understanding what drives variation in species diversity in space and time and limits coexistence in local communities is a main focus of community ecology and biogeography. My doctoral work aims to document patterns of ant diversity and explore the possible ecological mechanisms leading to these patterns. Elucidating the processes by which communities assemble and species coexist might help explain spatial variation in species diversity. Using a combination of manipulative experiments, broad-scale surveys, behavioral assays and phylogenetic analyses, I examine which ecological processes account for the number of species coexisting in ant communities. Ants are found in most terrestrial habitats, where they are abundant, diverse and easy to sample (Agosti et al. 2000). Hölldobler and Wilson (1990) noted that competition was the hallmark of ant ecology, and we know that ant diversity varies along environmental gradients (Kusnezov 1957). Thus ants are an ideal taxon to examine the factors shaping the structure of ecological communities and how the determinants of community structure vary in space.

Cette étude a pour objectif principal dinventorier les espèces de poissons de la partie congolaise de lInkisi et de contribuer à la connaissance de leur structure de peuplements. A partir des pêches expérimentales et artisanales effectuées entre octobre 2005 et octobre 2008 et des spécimens déposés antérieurement dans les musées, 61 espèces appartenant à 38 genres et 15 familles ont été répertoriées. Trente-sept de ces espèces nétaient pas encore connues du bassin de lInkisi ; huit espèces sont endémiques et sont localisées en amont de la chute de Zongo : Barbus vanderysti, Labeobarbus sp. inkisi, Varicorhinus robertsi (Cyprinidae), Nannopetersius mutambuei (Alestidae), Schilbe zairensis (Schilbeidae) Aphyosemion labarrei (Nothobranchiidae) et Haplochromis sp. snoeksi et Chetia sp. inkisi (Cichlidae). Deux nouvelles espèces ont été décrites, Nannopetersius mutambuei et Haplochromis sp. snoeksi et les descriptions de deux autres sont en préparation. En ce qui concerne les proportions, la famille des Cyprinidae est la plus diversifiée (15 espèces soit 24,6 %); puis viennent les Mormyridae (11 espèces soit 18,0 %), les Cichlidae (9 espèces soit 7,1 %), les Clariidae (7 espèces soit 11,5 %), les Schilbeidae (4 espèces soit 6,6 %), les Mochokidae et les Amphilidae (3 espèces chacune soit 4,9 %) et les Nothobranchiidae (2 espèces soit 3,3 %). La somme des autres familles, représentées par une seule espèce, vaut 6,4 %. Les peuplements des poissons ont été échantillonnés aux filets maillants dans dix stations en prenant en compte 21 variables environnementales. Des analyses canoniques de redondance ont permis de mettre en évidence cinq variables environnementales (la couverture de la canopée, la présence de gros blocs de roches, la largeur de la rivière, le plancher rocheux et le substrat vaseux) qui influent sur la distribution des poissons et un plan spatial de peuplement de cinq types dhabitats : trois sur les affluents (Nsoni, Ngeba et Nua-Luidi-Bongolo-Wungu) et deux sur le cours principal (amont de la chute de Zongo et aval de la chute de Zongo). Les espèces qui caractérisent Nsoni, habitat à canopée sont Parauchenoglanis balayi, en terme dabondance et Barbus vanderysti, en terme de présence. Dans Ngeba, habitat à substrat boueux, les espèces caractéristiques en terme de présence sont Parachanna obscura et Ctenopoma nigropannosum. Dans le complexe Nua-Luidi-Bongolo-Wungu il y a, en terme dabondance, Varicorhinus latirostris, Raiamas kheeli et Garra congensis. Sur le cours principal, en amont de chute Zongo, habitats larges à fond rocheux, on retrouve, en terme dabondance Varicorhinus macrolepidotus, Labeo macrostomus, Doumea alula, Barbus cf. argenteus, et Chetia sp. inkisi. Finalement, en aval de la chute Zongo, habitat à gros blocs de roches, il y a 14 espèces caractéristiques en terme de présence dont les plus abondantes sont Labeo nasus, Steatocranus casuarius, Labeo greeni, Campylomormyrus rhynchophorus et Schilbe grenfelli. Dans la partie congolaise de lInkisi le gradient longitudinal de peuplement nest pas perceptible : laugmentation de la richesse spécifique amont-aval napparaît pas mais la composition spécifique amont-aval est différente. Les indices de diversités (richesse spécifique et équitabilité) variées en fonction des stations ; les plus élevés sont dans la station aval de la chute Zongo et les plus faibles dans la station Nsoni (pour la richesse spécifique) et la station Nua (pour léquitabilité). Les peuplements ichtyologiques semblent équilibrés dans la partie située en aval de la chute Zongo. Des affluents tel que Wungu ont été perturbés suite à lutilisation des techniques destructives (ichtyotoxique). Une planification et une gestion rationnelle des ressources halieutiques dans ce bassin doivent sopérer et être effectives pour préserver sa biodiversité. The present study aimed making a species inventory and contributing to the knowledge of the fish community structure of the Congolese part of Inkisi basin. Based on fishes collected between October 2005 and October 2008 using gill nets and local fishing gear, and specimens previously deposited in musea, a total of 61 species belonging to 38 genera and 15 families have been surveyed. Thirty seven of these species are new citations for the Inkisi basin; eight species are endemic and are only found upstream from the Zongo fall: Barbus vanderysti, Labeobarbus sp. inkisi, Varicorhinus robertsi (Cyprinidae), Nannopetersius mutambuei (Alestidae), Schilbe zairensis (Schilbeidae) Aphyosemion labarrei (Nothobranchiidae) and Haplochromis sp. snoeksi, Chetia sp. inkisi (Cichlidae). Two new species were described, Nannopetersius mutambuei and Haplochromis sp. snoeksi and two others are currently under preparation. The family Cyprinidae is the most diversified (15 species, 24.6 %), followed by Mormyridae (11 species, 18.0 %), Cichlidae (9 species, 7.1 %), Clariidae (7 species, 11.5 %), Schilbeidae (4 species, 6.6 %), Mochokidae and Amphilidae (with 3 species each one), and Nothobranchiidae (2 species, 3.3 %). The remaining families have only one species each and constitute 6.4 %. The fish communities were sampled using gill nets in ten stations taking into account 21 environmental variables. The canonical redundancy analysis retained five important environmental variables (canopy cover, presence of big rock blocs, river width, rocky bottom and muddy bottom) explaining the distribution of the fish species and revealed a spatial plan of five habitat types: three patterns for the affluents (i.e. Nsoni, Ngeba and Nua-Luid-Bongolo-Wungu) and two for the main channel (i.e. upstream of the Zongo fall and downstream of the Zongo fall). For the Nsoni, station with canopy, the typical species are Parauchenoglanis balayi and Barbus vanderysti, respectively, in abundance, and presence. In the Ngeba, station with muddy bottom, the typical species, in abundance, are Parachanna obscura and Ctenopoma nigropannosum. For the Nua-Luidi-Bongolo-Wungu complex, the typical species, in abundance, are Varicorhinus latirostris, Raiamas kheeli and Garra congensis. For the main channel of the Inkisi course upstream of the Zongo fall, wide habitats with rocky bottom, the typical species, in abundance, are Varicorhinus macrolepidotus, Labeo macrostomus, Doumea alula, Barbus cf. argenteus, and Chetia sp. inkisi. Finally, for the Inkisi main channel downstream of the Zongo fall, the station with big rock blocs, 14 species are typical in term of presence, among them the most common are Labeo nasus, Steatocranus casuarius, Labeo greeni, Campylomormyrus rhynchophorus, and Schilbe grenfelli. For the Congolese part of Inkisi no longitudinal gradient of the fish community assemblages was observed along the river. Species richness did not increase from upstream to downstream although the species composition between both is certainly different. Diversity index (species richness and equitability) vary according to station with the highest indexes observed downstream of the Zongo fall and the lower ones at Nua (for the equitability) and Nsoni (for the species richness). Fish communities seem equilibrated downstream of the Zongo fall. On the contrary affluents like the Wungu are being disturbed mainly by bad fishing practice (use of ichthyotoxin). A planification and sustainable use of the natural resources of the Inkisi River must be applied and executed to protect its fish diversity.

I examined the effects of hydrologic gradients and upland timber harvesting with different streamside management zone widths on yellow-poplar (Liriodendron tulipifera) processing and the associated macroinvertebrate community structure in the Cumberland Plateau ecophysic region, U.S.A. Prior to upland timber harvesting, 5.0 ± 0.1 g yellow-poplar leaf packs were constructed, zip-tied to gutter nails, and placed into 7 perennial and 6 temporary stream reaches with similar physiochemical and geomorphic characteristics. From December 2007 to May 2008, 3–5 leaf packs were collected per reach monthly. I found significant differences in the functional feeding group composition. Temporary reaches contained higher shredder, gathering-collector, predator, and total macroinvertebrate abundances. Shredder and total macroinvertebrate biomass was also higher in the temporary stream reaches. Gathering-collector biomass along one measurement was higher in the temporary streams. Perennial and temporary stream reaches contained similar macroinvertebrate diversity. Logging operations occurred from May 2008–December 2008. After logging operations ended, yellow-poplar leaf packs were placed into the perennial and temporary reaches of 3 control and 3 treatment streams (2 with same SMZ width, 1 different). From December 2008–May 2009. Leaf packs were collected monthly. Within the temporary and perennial stream reaches, no significant differences were detected between control and treatment yellow-poplar processing rates. No significant differences were detected between the control and treatment functional feeding group composition in abundance and biomass. Post-harvest, taxon richness increased in both the perennial control and treatment streams, while richness declined in the temporary control and increased in the temporary treatment. My findings indicate that when water is present, organic matter processing will function similarly to downstream reaches that have continual water flow. During seasonal flow patterns, macroinvertebrate communities associated with organic matter are present in temporary streams and may exceed perennial stream reaches in their density and biomass. This indicates that temporary streams are physically suitable habitats for macroinvertebrate fauna and contribute to a stream’s form and function. Overall, no observed distinct response in yellow-poplar processing rates or the associated macroinvertebrate community structure was detected within the perennial or temporary streams. Macroinvertebrate community structure varied spatially and temporally. On the taxonomic level, increases in taxa-specific abundance and biomass remain to be explained. Future research assessing interactions on the taxonomic level might help explain increases or decreases in abundance and biomass in relation to treatment effects. This study documented the response of organic matter breakdown and associated macroinvertebrate community structure during the 1st 5 months after logging. Thus, it is only a snapshot of stream ecosystem response to disturbance. Long-term studies are needed to evaluate full ecosystem response and recovery. Due to uncontrollable factors, I was not able to evaluate the success of different SMZ widths. Results documented should be treated with hesitancy, until full ecosystem response has been documented.

The distribution and abundance of stream fishes are influenced by many factors operating at multiple scales. Understanding how environmental variables influence the structure of stream fish assemblages is important for habitat assessment, stream restoration, and for predicting responses to environmental change. An emerging view in community ecology is that a focus on the functional structure of species assemblages in relation to environmental gradients may reveal more general patterns applicable across geographic regions. In this study, I used functional traits related to the trophic ecology, habitat use, and life-history strategies of fishes to examine the influences of environmental factors on stream fish assemblages. The research was carried out in two large regions: the Río Grijalva basin in southern Mexico and the Brazos and Trinity basins in Central Texas. In both regions, relationships between functional structure of stream fish assemblages and environmental factors at local, landscape, and regional scales were examined. Environmental characteristics at all three scales influenced the functional attributes of assemblages studied here. At the local reach scale, stream size, substrate characteristics, the availability of riffle and pool habitats, and abundance of in-stream cover structures were related to the functional trait composition of fish assemblages in the Río Grijalva Basin and in Central Texas streams. Landscape features most strongly related to functional structure in both regions were the extent of forested area in the watershed and the amount of land developed for urban and agricultural uses. At the regional scale, broad physiographic differences between ecoregions had a large influence on the taxonomic and functional composition of stream fish assemblages in Central Texas. Along the broad-scale longitudinal fluvial gradient of the Grijalva region, pronounced changes in the species composition, functional trait diversity, and trophic structure of fish assemblages were observed.