Diss. (sammafattning) Uppsala : Univ., 2001. / Härtill 6 uppsatser.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv. / Härtill 6 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Thesis (M.S.)--State University of New York at Binghamton, Department of Biological Studies, 2009. / Includes bibliographical references.

Thesis (M.S.)--Miami University, Dept. of Zoology, 2007. / Title from first page of PDF document. Includes bibliographical references (p. 20-26).

As the biomass of jellyfish (medusae of the Scyphozoa and Hydrozoa) has risen in numerous locations worldwide, awareness of their potential to exert a controlling influence on marine ecosystems and hinder the recruitment of fish stocks has increased. Medusae are capable of intensive, size–selective, predation on zooplankton, which may alter the composition of the plankton community. Jellyfish are often found in dense layers, up to hundreds of metres thick, which can extend horizontally for hundreds of kilometres. Such aggregations may benefit specialist feeders, such as turtles, that rely upon jellyfish for food and those fish that are able to find refuge under the jellyfish umbrellas. Nonetheless, the predominance of jellyfish in pelagic ecosystems is not generally viewed as desirable; in fact, this situation has been portrayed as the result of pollution and overexploitation of otherwise productive seas. However, jellyfish are sensitive indicators of environmental change, and their populations appear to respond to climatic fluctuations, so jellyfish warrant study for their intrinsic ecosystem role particularly given present concerns over climate change. With growing acceptance that fishery management should take an holistic ‘ecosystem approach’, knowledge of the interactions between jellyfish, fisheries and climate may be vital in progression towards the goal of ecosystem–based sustainable management of fisheries. Unfortunately, due to their gelatinous nature, medusae are difficult to sample using conventional netting techniques and data on changes in distribution and abundance are consequently sparse. Recent studies have demonstrated that medusae can be detected acoustically and that this technique could provide a rapid and cost–effective estimate of their biomass and distribution. This thesis reports my endeavour to demonstrate the ecosystem role of medusae and to develop acoustic techniques to monitor their biomass. Through regession analyses, I link the abundance of medusae (Aurelia aurita, Cyanea lamarckii, and Cyanea capillata) in regions of the North Sea to climatic fluctuations, as quantified by the North Atlantic Oscillation Index, and show that medusae may be important indicators of regional ecosystem change. The mechanisms linking climatic fluctuations to ecosystem changes are explored via a correlative modelling approach using General Additive Models; I show that the mechanisms are location dependent and explainable in terms of direct, rapidly responding (intra–annual) influences (surface warming, river run–off, and wind–driven mixing and advection) and longer–term (interannual) oceanographic responses (changes in circulation currents i.e. the northward extent of the gulf stream and relative strength of inflow into the North Sea of the North Atlantic current, Continental Shelf Jet and Arctic waters). I present correlative evidence for a detrimental impact by Aurelia aurita on herring 0–group recruitment, once the influence of interannual change in herring spewing stock biomass on recruitment is factored out through modelling with a Ricker stock–recruitment relationship. Similarly, a commensal relationship between whiting and Cyanea spp. medusae is shown to improve North Sea whiting survival to the 1–group. In progress towards the automated acoustic identification of species, I have developed an in situ discrimination tool that can distinguish between echoes from: Aequorea aequorea; Chrysaora hysoscella; clupeid fish (sardine, anchovy and round herring); and horse mackerel/Cape hake. The technique relies upon characteristic differences in echo strength between frequencies, which are determined for each jellyfish species and finfish group using combined multifrequency acoustic and pelagic trawl samples. This method has facilitated the world’s first acoustic–based estimate of jellyfish biomass in the Namibian Benguela Sea. The 12.2 million tonnes of biomass of medusae (Aequorea aequorea and Chrysaora hysoscella) in the Namibian Benguela Sea was found to be greater than the combined biomass, 3.6 million tonnes, of commercially important fish (horse mackerel, Cape hake, sardines, anchovy, and round herring) in the same area. These results suggest that medusae may have an important role in the Benguela ecosystem that has previously been overlooked and that their biomass should be monitored.

Knowledge about cetaceans in the Red Sea is limited with only a handful of sporadic or spatially-limited studies carried out to date. Funded by the Italian Cooperation through a Debt-for-Nature Swap programme and carried out in collaboration with the Egyptian NGO HEPCA, this thesis presents the results from the first ever systematic vessel-based surveys conducted in the southern Egyptian Red Sea from 2010 to 2013 using linetransect methodology. The main aims of the thesis were (a) to estimate cetacean abundance, (b) to determine distribution patterns and habitat use of the cetacean species, (c) to investigate movement patterns for species for which individual recognition techniques were suitable and (d) to identify areas of conservation concern for cetaceans with a particular focus on existing protected areas. Eight species were identified, of which five were commonly encountered (Stenella longirostris, S. attenuata, Tursiops truncatus, T. aduncus, and Grampus griseus) and three were rare (Pseudorca crassidens, Sousa plumbea, Balaenoptera edeni). Estimates of abundance using design-based line transect sampling techniques were obtained for five species: S. attenuata 10,268 (CV=0.26); S. longirostris 6,961 (CV=0.26); T. aduncus 659 (CV=0.69); T. truncatus 509 (CV=0.33), and G. griseus 367 (CV=0.37). Habitat modelling revealed that the two Stenella species were widely distributed across the study area. In contrast, T. truncatus was concentrated in waters around Ras Banas peninsula (in particular Satayah offshore reef), and T. aduncus was mainly found along the coast with possibly separate sub-populations in the northern and southern study area. G. griseus was only encountered in the southern part. The information provided in this study will allow the development of a conservation strategy for the protected areas and will serve as baseline information to carry out future survey work in the Red Sea.

Foi feita uma revisão bibliográfia sobre a aplicação da amostragem seqüencial em manejos de pragas. A metodologia para o desenvolvimento de planos de amostragem seqüencial, foi baseada na teoria de Wald. Verificou-se que a distribuição binomial ajustou-se aos dados de presença-ausência da cochonilha-branca Aulacaspis tubercularis na cultura da manga, obtidos em duas propriedades localizadas na região de Jaboticabal, interior do estado de São Paulo. Seis planos de amostragem seqüencial foram elaborados para o monitoramento dessa praga, três com níveis de erros iguais a 0; 20 e outros três com níveis de erros iguais a 0; 10. Dentre esses, foram elaborados: dois planos para a amostragem em ramos durante o período vegetativo, dois para a amostragem em ramos durante o período de frutificação e outros dois planos para a amostragem em frutos. Nos planos de amostragem seqüencial para ramos no período vegetativo foram utilizados níveis de segurança iguais a 0; 35 e níveis de dano econômico iguais a 0; 50. Já no período de frutificação, houve um rigor maior quanto ao uso desses níveis, devido à presença de frutos. Foram utilizados níveis de segurança iguais a 0; 20 para ramos e 0; 05 para frutos, e níveis de dano econômico iguais a 0; 30 e 0; 15 para ramos e frutos, respectivamente. Foram construídas tabelas para o processo de amostragem em campo, facilitando assim, o trabalho do amostrador. Com o uso dessas tabelas o produtor poderá decidir rapidamente se há, ou não, a necessidade de se realizar o controle dessa praga. / A bibliographical revision on the application of the sequential sampling in management of pests was made. The methodology for the development of plans of sequential sampling, was based on the theory of Wald. It was verified that the binomial distribution adjusted to data of presence-absence of the mango scale Aulacaspis tubercularis on mango crop, gotten in two properties located at the region of Jaboticabal, interior of the state of São Paulo. Six plans of sequential sampling was elaborated for the monitoring of this pest, three with errors levels equal to 0; 20 and others three with errors levels equals to 0; 10. Amongst these, they was elaborated: two plans for the sampling in branches during the vegetative period, two for the sampling in branches during the period of fructification and others two plans for the sampling in fruits. In the plans of sequential sampling for branches in the vegetative period security level equal to 0; 35 and economic damage level equal to 0; 50 had been used. Already in longer period of fructification, had a bigger severity how much to the use of these levels, due to presence of fruits. Security levels equals to 0; 20 for branches and 0; 05 for fruits, and economic damage levels equals to 0; 30 and 0; 15 for branches and fruits, respectively, had been used. Tables for the sampling process in field, thus facilitating, the sampler's work was constructed. With the use of these tables the producer will be able to decide quickly has itself, or not, the necessity of if carrying through the control from this pest.

A Bacia do Corumbataí é usada como principal fonte de abastecimento de água para os municípios de Piracicaba e Rio Claro, sendo o Rio Passa-Cinco seu principal tributário. A Bacia do Passa-Cinco pode ser considerada um modelo conveniente para o estudo de conservação de biodiversidade por conter os principais agroecossistemas existentes no estado de São Paulo. Para que sejam estabelecidas estratégias conservacionistas, são necessárias informações de como a biodiversidade é afetada e quais estratégias as populações de espécie silvestres lançam mão para se manter em remanescentes florestais alterados. Pequenos mamíferos tais como roedores e marsupiais, podem ser considerados um bom grupo para ajudar a responder essas questões, pois esse grupo desenvolve um importante papel ecológico em ambientes florestais, através da predação e dispersão de sementes. De agosto de 2003 a janeiro de 2005 foram realizados levantamentos de pequenos mamíferos utilizando 160 armadilhas do tipo Sherman distribuídas em linhas, em 16 sítios amostrais, sendo 4 em cada tipo de ambiente predominante na paisagem: floresta nativa, plantações de Eucalyptus, plantações de cana-de-açúcar e pastagens. Durante esse período, foram capturados 177 indivíduos de roedores e marsupiais distribuídos em oito espécies, com um sucesso de captura de 0.77%. Houve diferença significativa entre os ambientes estudados em termos de abundância, mas não em termos de riqueza de espécies, podendo-se observar uma clara separação entre habitats florestais e não-florestais. Os remanescentes florestais nativos da região, aparentemente, perderam as espécies mais exigentes com relação à qualidade do habitat, de forma que a comunidade atual é formada basicamente de espécies generalistas e características de áreas degradadas. A perda de espécies florestais não somente altera a comunidade de pequenos mamíferos, como favorece o aparecimento de espécies de áreas não-florestais que podem trazer, entre outras coisas, problemas de saúde pública. Ainda assim, a comunidade de pequenos mamíferos da bacia do Rio Passa-Cinco é meritória de esforços conservacionistas, que devem priorizar estudos relacionando o cumprimento das leis ambientais com as alterações que isto possa gerar na comunidade de pequenos mamíferos. / The Corumbataí Basin is used as the main source of water supply for the municipal districts of Piracicaba and Rio Claro, being the Passa-Cinco River its main tributary. The Passa-Cinco river basin can be considered as a convenient model for the study of the conservation of biodiversity for it contains the main existing agroecosystems in the state of São Paulo. So that conservationist strategies can be established, some information is required, such as how biodiversity is affected, and which strategies the population of wild species use to keep themselves in the altered forest remainings. Small mammals, such as rodends and marsupials can be considered a good group to help answer these questions, for this group develops an important ecological role in forest environments, through the predation and dispersion of seeds. From August 2003 to January 2005 surveys on small mammals were carried out using 160 Sherman type traps distributed in lines, in 16 sample country properties, being 4 in each type of environment that is predominant in the landscape: native forest, Eucalyptus plantation, sugar-cane plantation and pastures. In this period, 177 rodend and marsupial individuals were captured, which were distributed in 8 species, with a 0,77% rate of success in capture. There was significative difference among the studied environments in terms of abundance, but not in terms of the richness of the species. Also, we could observe a clear distinction between forest and non-forest habitats. Apparently, the native forest remainings in the region lost their species which are the most demanding in relation to the quality of habitat, in such a way that the current community is basically formed of generalists, which are a characteristic of degraded areas. The loss of forest species not only alters the community of small mammals, but also favors the occurrence of species from non-forest areas which can bring, among other things, problems related to public health. Eventhough, the small mammal community from the Passa-Cinco river basin is worth conservationist efforts which must give priority to studies relating the environmental law enforcement to the changes this might generate to the community of small mammals.

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