Teses e dissertaçõeshttps://repositorio.ufscar.br/handle/ufscar/15382024-03-29T15:45:39Z2024-03-29T15:45:39ZA diversidade críptica da comunidade zooplanctônica em lagoas intermitentes do semiárido brasileiro: avaliação dos mecanismos de resiliência a alterações ambientaisSantos, Felipe Antonio doshttps://repositorio.ufscar.br/handle/ufscar/196122024-03-08T17:10:56Z2023-09-29T00:00:00ZA diversidade críptica da comunidade zooplanctônica em lagoas intermitentes do semiárido brasileiro: avaliação dos mecanismos de resiliência a alterações ambientais
Santos, Felipe Antonio dos
The zooplankton community plays a highly relevant role in temporary freshwater ecosystems. Comprising various groups of organisms such as rotifers, cladocerans, copepods, and other microcrustaceans, including Anostraca and Conchostraca, this community plays a vital role in maintaining the health and stability of these environments. It acts as a key link in energy flow and nutrient cycling, connecting different trophic levels and influencing the dynamics of aquatic ecosystems. In this study, we investigated the dynamics and resilience of the zooplankton community in temporary ponds located in the semi-arid region of Pernambuco. Our main objective was to evaluate the impact of different environmental conditions, such as soil type and trophic state of the ponds, on this community. In the first article, we identified that both soil type and trophic state of the ponds exert a significant influence on the presence or absence of various zooplankton species. These findings revealed that some species occur preferentially in clearer environments, while others prefer turbid environments. In the second article, we analyzed the hatching rates of resting forms and the resilience of the zooplankton community, which were influenced by the depth and soil type of the ponds. Remarkably, ponds with rocky soil exhibited a higher hatching rate compared to ponds with clayey soil. We also found that the difference in the composition of hatched organisms increases as the depth of the pond increases. In the third article, we investigated how the hatching rate of the dormant zooplankton community is affected by land use and occupation in the surrounding areas of the ponds. We found that human impact near temporary ponds is directly related to a lower hatching rate of the dormant community, especially in more impacted environments. This research provided a comprehensive insight into the dynamics of the zooplankton community in temporary ponds in the semi-arid region of Pernambuco, highlighting the importance of environmental conditions such as soil type and trophic state of the ponds in the initial composition and temporal succession of communities.
2023-09-29T00:00:00ZIdentificação de microalgas de água doce: construção de banco de dados e avaliação de interações planctônicas através de MALDI-TOF MSMello, Rodrigo Ventura dehttps://repositorio.ufscar.br/handle/ufscar/194582024-02-23T16:59:28Z2023-08-30T00:00:00ZIdentificação de microalgas de água doce: construção de banco de dados e avaliação de interações planctônicas através de MALDI-TOF MS
Mello, Rodrigo Ventura de
Freshwater microalgae constitute a very diverse group with major ecological importance. However, the delimitation of species in some groups remains inconclusive. The absence or difficulty of recording sexual reproduction in the group implies the need to use other species concepts in addition to the biological concept. The integrative approach, which includes morphological, chemotaxonomic, biomolecular analyses, and physiological and ecological data, is proving increasingly important for a better delimitation of microalgae species. The inclusion of the ecological concept of species in the integrative taxonomy allows a better understanding of the functional diversity of these organisms. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) is a tool with potential for distinguishing strains and species of microalgae, but databases with reference spectra of microalgae are nonexistent. Thus, we implemented a database with 23 axenic strains and tested its ability to identify strains and species of microalgae in an open-source software. The identification by spectra similarity showed a satisfactory ability to differentiate strains and species, even with cultures performed under different abiotic conditions. We also compared the MALDI-TOF MS spectra of 18 strains of closely related species grown in axenic conditions with the spectra of the same strains in different treatments with two bacteria, to integrate ecological data – of species interaction – in the specific delimitation of a family of coccoid green microalgae. Strains of A. densus and A. fusiformis showed similar responses of metabolite production when cocultured with bacteria. Two strains, CCMA-UFSCar 131 and 024, were shown to be possibly a new species and a case of misclassification, respectively. The spectra database can be of great help in the rapid identification of microalgae. Together with the ecological data, the identification by MALDI-TOF MS can help in the complex specific delimitation of freshwater green microalgae.
2023-08-30T00:00:00ZAnálise espaço-temporal de encalhes de aves marinhas no litoral sul e sudeste brasileiroRodrigues, Regiane da Silvahttps://repositorio.ufscar.br/handle/ufscar/194502024-02-23T14:25:47Z2023-12-14T00:00:00ZAnálise espaço-temporal de encalhes de aves marinhas no litoral sul e sudeste brasileiro
Rodrigues, Regiane da Silva
The group of seabirds is composed of different species with unique physiological adaptations that allow them to forage and migrate long distances in the ocean. These characteristics make them a crucial link between marine and terrestrial environments, providing essential services for ecosystem balance. However, they are exposed to a wide range of natural and anthropogenic threats that impact their populations, potentially resulting in the stranding of moribund or dead specimens on beaches worldwide. The processes behind these events are poorly understood, so this study aimed to analyze the strandings of seabirds on the south and southeast coasts of Brazil. The goal was to understand possible spatial and temporal patterns of strandings, as well as the influences of environmental and anthropogenic variables, during the years 2016 and 2019. The results revealed a well-defined spatial pattern, with higher abundance, richness, and diversity of strandings in the southern mesoregions and a decrease in the northern mesoregions along the Brazilian coast. Temporal patterns varied mainly by migratory status. Ecological indices of resident species showed higher strandings during the spring months and were positively related to wind intensity, reflecting primarily the reproductive period and fledgling departure of these species. Migratory species from the northern hemisphere also experienced peak strandings during the spring months, related to increased wave height and wind intensity. Six major mass stranding events were observed in the spring of 2016, mainly involving Manx shearwaters Puffinus puffinus. For these species, the southern hemisphere spring reflects the trans-equatorial migration period they undertake to reach the Patagonian Shelf during the northern hemisphere winter. Strandings of birds from the southern hemisphere mainly occurred in the winter months when these species migrate to the Brazilian coast during the non-breeding period. Abundance, richness, and diversity were higher with increased wind intensity and decreased sea surface temperature. Among southern species, the Magellanic penguin Spheniscus magellanicus exhibited the highest abundance, also occurring in winter months, with females and young individuals being predominant in the stranding population structure. The stranding of this species decreased with increasing temperature and increased with higher wind intensity. However, when removing the five extreme stranding events, particularly in 2018, which seem to be related to ENSO stages, wind intensity loses significance. This exemplifies the importance of this variable in the drift of bodies at sea reaching the beaches. This thesis provides valuable information about the dynamics of the seabird community on the Brazilian coast, being the first to evaluate such an extensive stretch of beaches in Brazil and the strandings in the mesoregions that compose it. Additionally, it demonstrates that the southern coast, particularly in the state of Santa Catarina, deserves attention for the implementation of conservation actions directed towards different species of seabirds.
2023-12-14T00:00:00ZPadrões Ecogeográficos da interação parasita-hospedeiro: uma abordagem EcoHealthSilva, Guilherme Gonzaga dahttps://repositorio.ufscar.br/handle/ufscar/193702024-02-19T12:15:26Z2023-09-26T00:00:00ZPadrões Ecogeográficos da interação parasita-hospedeiro: uma abordagem EcoHealth
Silva, Guilherme Gonzaga da
One of the most recognizable biogeographic patterns is the latitudinal gradient of biodiversity. From it, several other patterns have been derived and studied for decades. The interactions among organisms are also subject to these patterns. Of particular interest are the parasitic organisms, since many of these organisms act as vectors of pathogens of medical and veterinary interest. The close dependence of parasites on their hosts generates particularities in the way these organisms respond to variations in different biotic and abiotic factors. The elucidation of these elements can subsidize innovative interdisciplinary approaches such as ecohealth, which seeks to integrate human, animal, and environmental health. Thus, the present thesis aimed to explore the bioclimatic factors at macroscale and the role of population distribution dynamics and diversity of hosts and vectors in host-parasite interactions. The results added evidence of the role of abiotic gradients on parasites at a broader scale and indicate that different modes of parasitic lifestyles can lead to different responses to these factors. It was also demonstrated that host biodiversity influences the transmission of pathogens in systems involving vectors. However, the inclusion of multiple host-parasite systems can hinder the study of these interactions due to the underlying complexity of population dynamics.
2023-09-26T00:00:00Z