O presente trabalho tem como objetivo geral o estudo da composição e estrutura da macrofauna bêntica em escala espacial e sazonal, da região de Cabo Frio (RJ). O aspecto temporal nessa área é especialmente importante devido a ocorrência do fenômeno sazonal da ressurgência costeira. Esse ocorre devido alguns fatores físicos característicos da área, tais como mudanças na topografia e na direção da costa, e principalmente, em decorrência das condições meteorológicas atuantes no local. A interação desses fatores favorece, principalmente no verão, o ressurgimento próximo à costa da Água Central do Atlântico Sul (ACAS), uma massa de água fria e rica em nutrientes. Essa massa de água disponibiliza grande quantidade de nutrientes para o fitoplâncton das camadas superficiais, ocasionando uma elevada produção primária nova. Parte dessa produção é exportada para o fundo incrementando a biomassa bêntica. Assim, a comunidade bêntica assume um papel vital no ecossistema, sendo tanto receptora como fornecedora de energia. Os descritores de comunidade (densidade, biomassa, riqueza, diversidade e equitatividade) e a identificação dos grupos tróficos de Polychaeta foram analisados entre 40 e 1000m de profundidade e em três épocas do ano, inverno de 2001 e verão e primavera de 2002. A integração dos dados biológicos com os ambientais mostrou que as variações espaciais na estrutura e composição dos organismos foi relacionada à profundidade e ao tipo de sedimento verificado nas estações. A estrutura da comunidade também apresentou variações temporais, especialmente nas estações situadas na plataforma continental, respondendo à entrada de matéria orgânica decorrente do evento de ressurgência. / The main objective of the present study was to evaluate the composition and spatial and seasonal structure of the macrobenthic fauna off Cabo Frio (RJ). The temporal scale was investigated in the light of the seasonal coastal upwelling. This phenomenon occurs due to changes in bottom topography and in the coastline direction, and specially, because of the prevailing seasonal NE winds in the area. The interaction of these factors enables the South Atlantic Central Water (SACW) to rise up and reaches the surface, intensively during the summer months. Large amounts of nutrients are then brought to the euphotic zone, enhancing primary productivity. This high productivity increases food supply for benthic communities by sinking of particulate organic carbon. In this way, the benthic communities are an important link in the ecosystem. The density of organisms, biomass, species richness and evenness and also the trophic group of Polychaeta were analyzed in a depth gradient from 40 to 1000m during the 2001 winter and 2002 summer and spring. Faunal distributional patterns and species composition correlated with environmental variables, especially depth and sediment types. The faunal structure also showed temporal changes along the sample period, especially in the stations located in the continental shelf due to the input of organic matter to the sea floor.

The composition and distribution of fish assemblages was examined in a floodplain lake system in the Amazon basin. Quantitative samples were collected during the 1992-1993 flooding season at Marchantaria Island, Solimoes River. A total of 25,819 specimens representing 8 orders, 30 families, 101 genera and 139 species of fish were collected. Analysis of species richness distribution among 7 vegetation strata showed that vegetated sites had higher species richness than unvegetated sites. Stands of Paspalum repens had the most diverse fish fauna. Canonical correspondence analysis (CCA) was used to investigate relationship between fish assemblages and 16 environmental variables. CCA revealed that dissolved oxygen, water transparency, water depth and aquatic vegetation structure were significantly related to fish assemblage organization. The results suggest that physiological adaptations to hypoxia and habitat complexity play a major role in the organization of these assemblages. The morphology, ontogenetic development, shape variability and deposition of otolith microincrements are described for floodplain serrasalmin fishes. Serrasalmin otoliths were similar to other ostariophysan, nevertheless their shape was species-specific. Elliptical Fourier analysis showed that Mylossoma aureum lapilli were highly variable in shape when compared to closely related species. PCA and discriminant function analysis indicated that two distinct forms of lapillus can be recognized for M. aureum, and intra-species variation was higher than inter-species variation. Otolith microincrement analysis was tested for these fishes, and microincrement deposition validation showed that Piaractus brachipomus deposits otolith increments on a daily basis. Patterns of spatial distribution, growth and mortality characteristics of larvae and juvenile were examined for M. aureum inhabiting the Marchantaria Island floodplain. Otolith-derived birth date reconstruction showed that M. aureum spawning season extended from late November to March, and peak larvae recruitment to the island occurred in mid-December. Larvae and juveniles had different spatial distributions in relation to habitat usage. Instantaneous growth coefficients (g) varied from 0.0197(d�����) to 0.265(d�����) among cohorts. Early-season cohorts had wider otolith microincrements and higher instantaneous growth coefficients than late-season cohorts. Mortality estimated by the decline of loge (abundance) regressed on age indicated that cohort-specific instantaneous mortality varied significantly among cohorts, ranging from 0.027(d�����) (2.6%/d) to 0.103(d�����) (9.7%/d). / Graduation date: 2001

Bibliography: leaves 121-151. / xix, 151 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines seasonal variation in population numbers of Diamondback moths, and estimates mortality, due to parasitoids, of larvae at different stages of development. / Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 1996

This dissertation presents a contribution for the preservation of Aegla platensis, one of the most widely distributed species of anomuran crabs in South America, the only continent where they are found. For this, monthly collections were taken during twelve months, from July/2007 to June/2008, in the Lajeado Bonito (27º 25' 27'' S 53º 24' 39''W), a first order tributary of Rio da Várzea, town of Frederico Westphalen/RS. Specimens were collected by using traps containing lures of bovine liver and a surber sampler with 1 mm mesh. The objectives of the present contribution were: to estimate the population density of A. platensis; to determine the size of males and females in the first maturation; to determine the sex-ratio, the periods of reproduction and recruitment of juveniles; to study the seasonal distribution of the species. This dissertation is divided in three chapters, each one enclosing a pertinent subject to the biology of the A. platensis, in order to provide a more dynamic and objective reading and to facilitate the guiding of articles for publication in scientific magazines of the area. The first chapter deals with the morphologic sexual maturity in A. platensis by studying the changes in the ratios of the corporal dimensions of the animals. For this, 437 males with cephalothoracic length (CL) ranging from 6.00 to 31.75 mm (average 16.11 ± 7.4 mm) and 368 females with CL ranging from 6.08 to 27.92 mm (average 16.07± 6 mm). All the captured specimens were sexed and the following corporeal dimensions were measured: cephalothoracic length (CL) cephalothoracic width (CW), length of right chelipod (RC), length of left chelipod (LC) and height of the larger chelipod (HC). After the register of these measures, the crabs were returned to the stream, to the same place where they were collected. The analysis of morphologic sexual maturity was carried out using the Software Mature 2, considering the measures of CL as independent variables and relating them to the other dimensions, as for males and for females. Based on the relation between the carapace length and the measures of the propod in males and the abdomen width in females, the sexual maturity was esteemed in 19.9 mm of CL for males and 18.2 mm of CL for females. In a second chapter, aspects of the populational dynamics of A. platensis were characterized by studying the sexual ratio, the reproductive period (by the frequency of ovigerous females during the sampling period), the period of recruitment and the average size of males and females. A total of 503 males (180 adults and 323 juveniles), 378 females (169 adults, 187 juveniles and 22 ovigerous) and 76 unsexed juveniles were sampled. CL ranged from 6 mm to 31.75 mm in males, from 6.08 mm to 27.92 mm in females and from 1.39 to 5.98 mm in unsexed juveniles. The average sizes were 16.27 (± 7.35), 16.11 (± 5.95), 4.73 (± 0.96) mm for males, females and juveniles, respectively. The average sexual ratio was 1.33 (± 0.38) male/female. Twenty-two ovigerous females were collected, corresponding to 5.82% of the females captured, being 10 in the winter, 4 in the spring, 7 in the summer and 1 in the autumn. The size of these females varied from 16.7 to 24.87 mm CL. The presence of juveniles was verified in all seasons, more frequently in the summer. In the third chapter, we evaluated the spatial and temporal distribution of A. platensis. Besides morphometric data, physical-chemical parameters were also registered, as pH, dissolved oxygen, temperature of the water, electric conductivity, pluviosityl and water outflow. The sediment of each sampling site was characterized according to the size of the particles composing it. A total of 957 specimens was sampled using a surber sampler and traps made of pet bottles in a stretch of 150 meters throughout the stream. Of the total of individuals collected, 200 were sampled in winter (20.90%), 255 in spring (26.65%), 219 in summer (22.88%) and 283 in autumn (29.57%). The population density was calculated by the Petersen s method. The density of individuals/m2 was 3.83 in winter, 1.8 in spring, 3.29 in summer and 2.33 in autumn. The values of temperature of the water, pH, conductivity and dissolved oxygen were statistically similar between the seasons of the year. No relation was found between the physical chemical parameters of the water and the abundance of eglids. The average number of individuals collected varied throughout the seasons (p<0.05). Adult females presented negative correlation with rocks between 6 and 12 cm of diameter (P<0.01) and the number of juveniles increased with quantity of leaves in the substratum (p<0,05). / Esta dissertação apresenta uma contribuição para a preservação e manejo de Aegla platensis, uma das espécies de eglídeos de maior abrangência em distribuição na América do Sul, único local onde são encontrados. Para isso, foram realizadas coletas mensais durante doze meses, de julho de 2007 a junho de 2008, no Lajeado Bonito (27º 25 27 S 53º 24 39 W), um tributário de primeira ordem do Rio da Várzea, em Frederico Westphalen/RS. Os espécimes foram coletados com auxílio de armadilhas com iscas de fígado bovino e puçá com malha de 1 mm de abertura. Os objetivos da presente contribuição foram: realizar uma estimativa da densidade populacional de A. platensis; determinar o tamanho de machos e fêmeas na primeira maturação; determinar a razão sexual, o período reprodutivo e o de recrutamento de juvenis; estudar a distribuição espacial e temporal da espécie. A dissertação está dividida em três capítulos, cada um abrangendo um assunto pertinente à biologia de A. platensis, a fim de proporcionar uma leitura mais dinâmica e objetiva, além de facilitar o encaminhamento dos artigos para publicação em revistas científicas da área. O primeiro capítulo trata da maturidade sexual morfológica em A. platensis, a qual foi estimada através das mudanças nas proporções das dimensões corporais dos animais. Para isso, foram utilizados 437 machos com comprimento de cefalotórax (CC) variando de 6,00 a 31,75 mm (média 16,11± 7,4 mm) e 368 fêmeas com CC de 6,08 a 27,92 mm (média 16,07± 6 mm). Os indivíduos coletados foram sexados e mensurados nas seguintes dimensões corporais: comprimento de cefalotórax (CC), largura do abdome (LA), comprimento do própodo direito (CPD), comprimento do própodo esquerdo (CPE) e altura do maior própodo (ALT). Após o registro dessas medidas, os animais foram devolvidos ao mesmo local de captura. A análise de maturidade sexual morfológica foi realizada com auxílio do Software Mature 2, na qual foram utilizadas as medidas de CC, considerada como variável independente e relacionada com as demais, tanto para machos quanto para fêmeas. Com base na relação entre o comprimento da carapaça e as medidas do própodo calculou-se a maturidade dos machos, estimada em 19,9 mm de CC e, com base na largura do abdome estabeleceu-se a maturidade das fêmeas em 18,2 mm de CC. No segundo capítulo foram caracterizados aspectos da biologia reprodutiva de A. platensis. Avaliou-se a proporção sexual, o período reprodutivo (pela frequência de fêmeas ovígeras durante o período amostral), o período de recrutamento e o tamanho médio de machos e fêmeas. Foram amostrados 503 machos (180 adultos e 323 juvenis), 378 fêmeas (169 adultas, 187 juvenis e 22 ovígeras) e 76 juvenis com sexo indeterminado. O CC variou de 6 a 31,75 mm nos machos, de 6,08 a 27,92 mm nas fêmeas e de 1,39 a 5,98 mm nos juvenis não sexados. Os tamanhos médios foram de 16,27 (± 7,35), 16,11 (± 5,95), 4,73 (± 0,96) mm para machos, fêmeas e juvenis não sexados, respectivamente. A proporção sexual média foi de 1,33 (± 0,38) machos/fêmea. Foram amostradas 22 fêmeas ovígeras, 5,82% das fêmeas capturadas, sendo 10 no inverno, 4 na primavera, 7 no verão e 1 no outono. O tamanho destas fêmeas variou de 16,7 a 24,87 mm. A presença de juvenis foi verificada em todas as estações do ano, com maior frequência no verão. No terceiro capítulo, avaliou-se a distribuição espacial e temporal de A.platensis. Foram registrados dados morfométricos e físico-químicos , como pH, oxigênio dissolvido, temperatura da água, condutividade elétrica, pluviosidade e vazão de água. O sedimento de cada ponto foi caracterizado de acordo com o tamanho das partículas que o compunham. Foram coletados 957 indivíduos com puçá e armadilhas de garrafa pet dispostas em um trecho de 150 metros ao longo do arroio. Do total de indivíduos coletados, 200 foram no inverno (20,90%), 255 na primavera (26,65%), 219 no verão (22,88%) e 283 no outono (29,57%). A densidade populacional, calculada pelo método de Petersen, foi estimada em 3,83 indivíduos/m2 no inverno, 1,8 na primavera, 3,29 no verão e 2,33 no outono. Os valores de temperatura da água, pH, condutividade e oxigênio dissolvido foram estatisticamente semelhantes entre as estações do ano. Não houve relação entre esses parâmetros físicoquímicos da água e a abundância de eglídeos coletados. Houve variação na média de indivíduos coletados ao longo das estações (p< 0,05). A quantidade de fêmeas adultas apresentou correlação negativa com a quantidade de rochas entre 6 e 12 cm de diâmetro (p<0,01) e o número de juvenis aumentou com a quantidade de folhiço no substrato (p<0,05).

The freshwater polychaete Manayunkia speciosa was identified as an obligate host of the salmonid parasite Ceratomyxa shasta in 1997, prompting increased research on the small benthic invertebrate. Ceratomyxa shasta infection in fish can cause mortality, and presents a disease risk for both hatchery and wild salmon and trout. Ceratomyxa shasta is endemic to rivers of the Pacific Northwest, and its effects have been particularly well documented in the Klamath River, Oregon and California. One option for managing C. shasta impacts is by decreasing densities of M. speciosa through habitat manipulation, thus decreasing amplification of the parasite. The Klamath River is regulated by irrigation and hydropower dams, thus manipulating the hydrograph to destabilize habitat is a possibility. Decreasing habitat through flow manipulation requires a thorough understanding of the hydraulic environment of polychaete habitat, and how that environment changes with discharge. This thesis proposes an influence diagram of physical variables driving M. speciosa density, and investigates several of them. Samples were collected for enumerating M. speciosa density from nine sites in the Klamath River over 15 months, and seasonal density changes were examined, as were the relationships between density and hydraulic variables (depth, average velocity, substrate size, Reynolds number, Froude number). Density increased directly with depth and inversely with velocity, and was greater on small (silt, sand) and large (boulder, bedrock) substrate relative to medium substrate (gravel, cobble). Density was highest in the summer (July, August, September), and there was evidence that summer densities were influenced by spring discharges through the mechanism of substrate mobilization. Differences in infection prevalence among seasons and habitats were also investigated; however, very low overall incidence of infection limited any conclusions. Based on these results, it is recommended that habitat modeling for management of M. speciosa populations include a habitat stability component that incorporates s whether peak discharge the previous year surpassed a stability threshold. / Graduation date: 2013

Fire plays an important role in structuring and maintaining savanna grassland ecosystems. Although regular fires are a characteristic feature of savannas, the effects of fire frequency on these systems are less well known, particularly with respect to how frequency of fire influences large herbivore distribution and behaviour. The expectation is that large herbivores should be attracted to frequently burned sites as a consequence of changes in forage quality and quantity, and/or vegetation structure and composition. The former could be driven by alterations in soil nutrients, such as N and P. Alterations in vegetation also could be important in determining risk of predation. For example, an increase in woody vegetation could decrease predator visibility making large herbivores more vulnerable to predation. The objectives of this study were to investigate the effects of long-term alterations in fire frequency on herbivore distribution and behaviour, as well as the mechanisms (soil nutrients, vegetation structure and composition, and forage quality and quantity) potentially driving the distribution of large herbivores. To address these objectives, I conducted large herbivore surveys on a bi-weekly basis from 2009-2010 in a series of plots in the Experimental Burn Plots (EBPs) burnt at different frequencies (annual, triennial and unburnt) over the last five decades at three study sites in the Kruger National Park, South Africa. Surveys also were conducted on new plots that were established adjacent to the long-term plots. These new plots have a fire return interval of 4 years which is similar to the triennially burned plots of the EBPs. They were established in the landscape adjacent to the EBPs to assess whether the responses of herbivores to fire observed in the EBPs reflected was at landscape level. The distribution of all large herbivore species combined and of grazers (e.g. zebra) or browsers (e.g. kudu) only were not affected by fire frequency. In contrast, the abundance of mixed-feeders, such as impala, was significantly higher in the unburnt (control) and annually burned plots than the triennially burned plots. Although season did not have a significant impact on the distribution of browsers and mixed-feeders, overall more grazers were recorded across all burn treatments in the dry season compared to the wet season. Similar patterns of herbivore distribution were observed between the new plots and the triennially burned EBP plots, suggesting that responses observed to the long-term fire frequency treatments reflects herbivore responses at the landscape level. The long-term fire frequency treatments significantly affected soil nutrients (N, organic C, P, and K were significantly lower with annual burning), vegetation structure (abundance of woody plants were greater in unburned plots), and forage quantity (unburned plots had higher biomass) but not quality. More frequent fires improved visibility by reducing tree height and density and herbaceous biomass, thereby potentially reducing predation risk, when compared to less frequent burning. As a result, herbivores selected sites with more frequent fires. The behaviour of the herbivore species investigated was predominantly influenced by seasonal-induced changes to their environment rather than fire frequency. In the wet season irrespective of the burning treatment visibility was low due to high rainfall that increases plant biomass, whereas in the dry season visibility was improved because there is little to no rainfall. This potential alteration in predation risk likely resulted in herbivores being more vigilant in the wet season than the dry season. Overall, results from this study suggest that the combination of fire frequency and season drive herbivore distribution and behaviour by altering mainly the vegetation structure which can influence predation risk. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.