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Philosophiae Doctor - PhD / 2022-04-30

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Trade-offs in traits conferring success in permanent and ephemeral habitats are often at odds with few species being able to persist in both types of environments. I examined the effect of sunfish predators on two species of south Florida crayfish to establish the mechanism that limits one species, Procambarus alleni, to short-hydroperiod environments. The crayfish assemblage response to a gradient of sunfish predators and the effect of predation on P. fallax alone was examined. I also examined the effects of sunfish on crayfish growth and quantified activity levels and risky behaviors of both crayfish species. P. alleni dominated at low sunfish densities but dominance shifted with increasing sunfish density. P. alleni was more active and likely to initiate risky behaviors, suggesting that sunfish predators remove the more active P. alleni, reducing their numbers disproportionally to those of P. fallax and allowing P. fallax to dominate crayfish assemblages in long-hydroperiod wetlands. / by Christopher M. Kellogg. / Thesis (M.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

In examining the intentional relationship between the conservationist and the shark in South Florida, this thesis considers the latter as both a scarce natural resource - caught up in what Clifford Geertz citing Weber referred to as "webs of significance" (Geertz 1973:5) - and as a reflection of dynamic human conceptions of nature : a meta shark. This complex relationship is described by interpretations of conservation discourse recorded through ethnographic interviews that demonstrate how these perceptions have been influenced by factors such as personal experiences, film and text, and broad changes in the relationship between humans and nature since the early days of the environmental movement. By linking these perceptual changes with changes in American shark conservation policy, this work not only explains a relationship between culture, perception, and policy, but also celebrates the emergence of a multispecies marine community. / by Patrick Nason. / Thesis (M.A.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Fish predation can have structuring effects in aquatic communities, but the most important fish predators are not always immediately obvious. Generalist fish predators often occupy similar habitats and consume similar prey making determination of their consumptive impacts difficult. Understanding these consumptive impacts is important for understanding complex wetland food webs. I collected warmouth (Lepomis gulosus), bluespotted sunfish (Enneacanthus gloriosus), and dollar sunfish (Lepomis marginatus) in two seasons from sloughs for both diet and bioenergetics analysis. Macroinvertebrates dominated diets of the three species, and nonparametric analyses revealed evidence of diet ontogeny in warmouth and potential competition for prey items among gape-matched individuals. Bioenergetics modeling revealed high levels of macroinvertebrate comsumption by these species relative to macroinvertebrate reproductive output suggesting that when combined with other sources of mortality, consumptive pressures placed by sunfish on benthic macroinvertebrates may be quite large. / by Jacob Bransky. / Thesis (M.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Orientador: Marcelo Antonio Amaro Pinheiro / Banca: Maria Helena de Arruda Leme / Banca: Evandro Severino Rodrigues / Banca: Carolina Pacheco Bertozzi / Banca: Ursulla Pereira Souza / Resumo: Os estuários estão entre as áreas mais produtivas do planeta, sendo fundamentais ao ciclo de vida de muitas espécies e detentoras de elevado valor agregado. O Sistema Estuarino de Santos-São Vicente (SES) é conhecido por seu histórico de degradação ambiental, pela presença de uma expressiva área portuária, industrial, moradias ilegais (palafitas), além da descarga de esgoto e emprego para atividades pesqueiras. Apesar de sua intensa ocupação, poucos estudos têm sido efetuados sobre sua fauna aquática, em especial sobre a ictio e carcinofauna. Desta forma, a fauna de peixes e crustáceos foi avaliada com o intuito de inferir sobre o status de qualidade ambiental deste estuário. Foram realizadas coletas mensais por arrasto, durante dois anos, em nove áreas com diferentes pressões antropogênicas. Neste período, foram coletadas 93 espécies de peixes e 24 de crustáceos, com 12.170 e 2.164 indivíduos, respectivamente. Duas espécies de peixes apresentaram abundância muito superior às demais: Diapterus rhombeus (carapeba; Gerreidae) e Genidens genidens (bagre; Ariidae), representando 57% da abundância; o mesmo ocorreu com os crustáceos, no caso com apenas uma espécie, Callinectes danae (siri azul; Portunidae), que representou 58% da abundância destes artrópodos. Em relação a densidade dos peixes em sua maioria foram marinho-migrantes (57%), ocupando principalmente a área do alto estuário com grande abundância e baixa biomassa proporcional, em segundo lugar foram estuarino-residentes ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The estuaries are one of the most productive place on planet, essential to the life cycle of many species and high earned value. The Santos-São Vicente Estuary System (SES) is known for its history of environmental degradation, the presence of a significant harbor area, industrial, irregular dwellings (stilt houses), as well as the sewage discharge and employment for fishing activities. Despite its history, few studies about aquatic fauna have been made, especially about the ichthyo and carcinofauna. Because of that fishes and crustaceans was evaluated in order to analyse the environmental quality status of the estuary. Sampling was carried out for two years in 9 stations with differents anthropogenic pressures. A total of 12,170 fishes and 2,164 crustaceans from 93 and 24 taxas, respectively were captured. Two fishes, Diapterus rhombeus and Genidens genidens and one crustacean, Callinectes danae, showed high abundance (57% and 58% of total). For fishes, the major density was marinemigrants (57%), mainly on the high estuary with high abundance and low proportional biomass, the second guild were the estuarine-residents (31%), mostly on the main channels. The SES was classified as moderately impacted, the entrance of Harbor Channel showed the highest diversity in contrast of the high estuarine area. The hypothesis of local impacts over community was reject, the communities in general seem to be adapted by the existing pressures. The increase of anthropic pressure in the SES is a reality due to the port activities and human population density, for that reason an effective and long-term monitoring of aquatic fauna is recomended that continuously assesses the magnitude and variation (Spatial and Temporal) of anthropic impacts / Doutor

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Electronically collected animal movement data has been analyzed either statistically or visually using generic geographical information systems. The area of statistical analysis in this field has made progress over the last decade. However, visualizing the movement and behavior remains an open research problem. We have designed and implemented an interactive visualization system, MarineVis, to visualize geospatial uncertainty in the trajectories of marine animals. Using MarineVis, researchers are able to access, analyze and visualize marine animal data and oceanographic data with a variety of approaches. In this thesis, we discuss the MarineVis design structure, rendering techniques, and other visualization techniques which are used by existing software such as IDV to which we compare and contrast the visualization features of our system. Finally, directions of future work related to MarineVis are proposed which will inspire others to further study the challenging but amazingly interesting and exciting research field of marine visualization. / Marine animal movement is a fundamental yet poorly understood process. One of the reasons is because our understanding of movement is affected by the measurement error during the observation and process noise. Differentiating real movement behavior from observation error in data remains difficult and challenging. Methods that acknowledge uncertainty in movement pathways when estimating constantly changing animal movement have been lacking until this time. However with the arrival of state-space models, this problem is partially solved as SSMs acknowledge this problem by allowing unobservable true states to be estimated from data observed with errors which arise from imprecise observations. State-space models use Markov Chain Monte Carlo methods which generate samples from a distribution by constructing a Markov Chain where the current state only depends on the immediately preceding state. The task of fitting SSMs to data is challenging and requires large computational effort and expertise in statistics. With the arrival of the WinBUGs software, this formidable task becomes relatively easy. Though using the WinBUGs software researchers try to visualize the tracks and behaviors, new problems appear. One of the problems is that when marine animals come back to certain places or animals' tracks cross each other several times, the tracks become cluttered and users are not able to understand the direction. Another problem of visualizing the confidence intervals generated using SSMs is that images generated using other systems are static in nature and therefore lack interactivity. Information becomes cluttered when too much data appear. Users are not able to differentiate tracks, confidence intervals or the information they would like to visualize. Acknowledging these, we have designed and implemented an interactive visualization system, MarineVis, where these problems are overcome. Using our system the confidence intervals generated using the SSMs, can be visualized more clearly and the direction of the turtle tracks can be understood easily. Our system does not occlude the underlying terrain as much because the glyphs are localized at the sample points rather than being spread out around the entire path. Our system encodes both direction and position rather than just position. Users can interactively limit the view of data points as a subset of available data points on a path, in clustered regions, to reduce congestion, and can animate the progression of the animal along its trajectory which is absent in existing approaches. All these results are visualized over NASA World Wind maps that facilitates the understanding of the tracks.