https://ri.ufs.br/jspui/handle/riufs/2415 2026-04-09T02:53:49Z https://ri.ufs.br/jspui/handle/riufs/24734 Título: Reconstruções paleoecológicas da megafauna do Pleistoceno final da Região Intertropical Brasileira Autor(es): Cruz, Evelyn Nathália da Silva Abstract: Pleistocene megafauna, composed of large-bodied mammals resilient to Quaternary climatic fluctuations, exhibited a wide distribution across the Brazilian territory, particularly within the Brazilian Intertropical Region, favored by high climatic suitability. The subsequent weakening of these populations, driven by climate changes and associated factors such as the arrival of PaleoIndians in South America, contributed to their extinction at the beginning of the Holocene, resulting in profound changes in ecosystem structure and functioning. The ecology of extinct species can be investigated through paleoecological tools, including stable and radiogenic isotope analyses. Stable carbon (δ¹³C) and oxygen (δ¹⁸O) isotopes allow inferences regarding diet and paleoenvironments, whereas radiogenic isotopes, such as strontium (⁸⁷Sr/⁸⁶Sr), enable the reconstruction of mobility and migration patterns. In tropical and subtropical regions, these signals are preferentially obtained from bioapatite due to the frequent degradation of collagen. However, to ensure the reliability of isotopic results, it is essential to assess fossil preservation and the potential influence of diagenetic processes, which remain poorly investigated in South America. In this study, we aimed to generate robust paleoecological inferences for different Pleistocene megafaunal species across distinct environmental contexts and analytical approaches. In the first chapter, we evaluated the quality of bioapatite in samples of Eremotherium laurillardi and Toxodontinae by comparing enamel, dentine, and associated soil, as well as testing sampling strategies for fossils recovered from natural tank deposits. In the second chapter, serial isotopic analyses were applied to identify seasonal dietary patterns in these species. In the third chapter, strontium isotope analyses demonstrated that Notiomastodon platensis exhibited migratory behavior, being capable of crossing geographic barriers such as the São Francisco River, and allowed the identification of the most recent specimen published to date. Finally, in the fourth chapter, we integrate isotopic data, climatic suitability, morphological attributes, and characteristics of fruits potentially consumed by browsing species, revealing a significant negative association between mean seed diameter and herbivore body mass. Taken together, this thesis strengthens methodological protocols, expands the application of isotopes in tropical contexts, and presents novel results on diet, seasonality, migration, and ecological interactions of Pleistocene megafauna in Brazil. 2026-02-23T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/24155 Título: Fatores determinantes da diversidade funcional e sua potencial associação com a diversidade da forma do corpo em comunidades de anuros Autor(es): Santos, André Luiz Conceição Abstract: Functional diversity is a very useful tool for understanding ecological processes. In this context, in the first chapter, we quantified and explored the current state of research on the functional diversity of terrestrial vertebrates. Based on the review of 490 articles, we observed an increase in the number of publications on the topic over time, particularly in the Palearctic, Nearctic, and Neotropical regions. There was a predominance of studies focused on birds across all biogeographic regions, while amphibians, reptiles, and mammals had significantly lower scientific output. Regarding functional traits, the most commonly used type was ecological, with the feeding category being the most frequently applied in studies. Among the functional diversity indices identified, functional richness (FRic), functional evenness (FEve), functional dispersion (FDis), and functional divergence (FDiv) were the most frequent. Our findings highlight the need for greater investment in research with a functional focus on terrestrial vertebrates, especially amphibians, reptiles, and mammals. In the second chapter, we quantified the functional diversity of anurans based on classic ecological traits (morphological, reproductive, and habitat use) and analyzed how climatic factors, historical processes, and anthropogenic disturbances (forest fragmentation) have affected the patterns of functional diversity of anurans in the Atlantic Forest, in northeastern Brazil. We showed that the functional divergence (FDiv) of anurans in the Atlantic Forest is influenced by historical environmental instability and the shape (circularity) of forest remnants. Additionally, functional evenness (FEve) was associated with climatic conditions (mean annual precipitation). However, functional richness (FRic) showed no apparent association with the predictors used. This study contributes to the understanding of the forces driving functional diversity, providing useful results to support effective conservation actions for anurans in the Atlantic Forest. Finally, in the third chapter, we investigated the degree of association between four diversity measures in anuran communities: functional diversity (FD), 3D morphological diversity (MD), phylogenetic diversity (PD), and climatic niche diversity (CND). Additionally, we evaluated the hypothesis that MD could serve as an efficient proxy for FD. We tested for phylogenetic signal in the phenotypic traits (classic and 3D shape) and climatic niches of anuran species and conducted simulations to assemble random anuran communities to quantify the association between FD, PD, MD and CND. The phylogenetic signals of functional, 3D morphological traits, and climatic niches of anuran species in the communities ranged from low to intermediate values. We observed a small increase in FD and MD values, while CND showed a clear growth with the inclusion of more species in the communities. On the other hand, PD did not show a significant increase with the larger number of species. We demonstrate for the first time that MD of phylogenetically close groups is more strongly correlated with FD than with CND or PD. Our results provide empirical evidence highlighting the potential of morphometric data in understanding functional diversity in communities. We also emphasize the importance of Biological Collection Museums as fundamental repositories for the preservation and study of functional diversity. 2025-02-27T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/24153 Título: Expressões da memória de hidratação de sementes: efeitos ambientais e genéticos durante a germinação de cactos da Caatinga Autor(es): Lima, Ayslan Trindade Abstract: Depending on the water availability where the seed was dispersed in semiarid ecosystems, the imbibition process during germination can be interrupted by the absence of water in the soil. Thus, the seed interrupts its germination process and loses the absorbed water to the environment, causing hydration and dehydration cycles (HD cycles) when water becomes available again in the environment. As a result of HD cycles, there may be an expression of seed hydration memory, which can preserve the physiological modifications resulting from discontinuous hydration and, primarily, promote adaptive advantages. Some of these advantages include, for example, increased desiccation tolerance, higher germination percentage, and enhanced speed and synchrony of the germination process. Additionally, seeds can also acquire tolerance to environmental stresses such as water deficit, thermal stress and saline stress. However, seed hydration memory expression may be influenced by genetic and/or environmental factors. Furthermore, until the results of the present study, there was no way to mathematically measure the level of hydration memory in seeds. Thus, the main objective of this doctoral thesis was to evaluate the different forms of expression of seed hydration memory in species of cacti native to the Brazilian semiarid region, as well as the creation of an index capable of measuring the level of hydration memory expressed by the seeds. To achieve this objective, this thesis was divided into five chapters structured in the format of scientific articles. Chapter 1 aimed to assess how seeds from the same population of Pilosocereus catingicola (Gürke) Byles & G.D. Rowley subsp. salvadorensis (Werderm.) Zappi (Cactaceae), produced and dispersed in different seasons of the year, express hydration memory under water deficit conditions. In this chapter, we observed that seeds from the same population, produced and dispersed at different times, express hydration memory differently during germination, with discontinuous hydration providing greater 11 acquisition of seed tolerance produced during the dry season. In chapter 2, we assessed how passing through HD cycles at different temperatures influences the acquisition of drought tolerance during the germination of Cereus jamacaru DC. subsp. jamacaru (Cactaceae) and Xiquexique gounellei (F.A.C. Weber) Lavor & Calvente subsp. gounellei (Cactaceae). In this case, we observed that the increase in temperature during the HD cycles reduces the expression of hydration memory in both species, impairing the acquisition of drought tolerance. In the third chapter, we evaluated the effects of rainfall levels in different populations on the expression of seed hydration memory during the germination of C. jamacaru subsp. jamacaru under water deficit conditions. We observed that after the HD cycles, seeds from more arid environments invest in optimizing germination time due to water limitation in the habitat, while seeds from less arid environments invest in increasing the quantity of germinated seeds. Chapter 4 aimed to propose the Germination Memory Index (GMI), a mathematical tool to quantify seed hydration memory. The fifth chapter, in turn, aimed to determine which factor (genetic or environmental) has a greater influence on the expression of seed hydration memory during the germination of C. jamacaru subsp. jamacaru under water deficit conditions. In this case, we observed that genetic factors (individual germination behavior) had a greater influence on the expression of hydration memory during the species' germination under water deficit. 2024-02-21T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/24150 Título: Autoalelopatia da polpa funicular de um cacto colunar que ocorre em diferentes ecossistemas do Nordeste do Brasil Autor(es): Santos, Bruno de Santana Abstract: The funicular pulp of fruits present in some Cactaceae is known to inhibit the germination of their own seeds. Furthermore, it has been reported in the literature that fruits can produce toxic or deterrent metabolites, often found in higher concentrations and diversities than in other plant organs, thus being able to prevent the germination of their own seeds. However, it has not yet been described in the literature how environmental conditions can influence the dynamics of this autoallelopathic effect. Therefore, the general objective of this dissertation was to evaluate the autoallelopathy of the funicular pulp of a columnar cactus that occurs in different ecosystems of Northeastern Brazil. We used as a study model the species Pilosocereus catingicola (Gürke) Byles & Rowley subsp. salvadorensis (Werderm.) Zappi (Cactaceae), which occurs in areas of Caatinga, a semiarid region of Northeastern Brazil; and in areas of Restinga, in the Brazilian coastal region. Furthermore, this columnar cactus species produces its fruits in the dry and rainy seasons. To achieve the general objective of this dissertation, this work was divided into two chapters. In the first chapter, the objective of the work was to perform the metabolite profile of the mucilaginous funicular pulp of the fruits of P. catingicola subsp. salvadorensis using the non-targeted metabolomics technique by Gas Chromatography coupled to Mass Spectrometry. The results for this chapter, it was possible to note 135 metabolites belonging to 19 chemical families. In addition, it was possible to conclude that environmental conditions directly influence the metabolism of the funicular pulp of the fruits of P. catingicola subsp. salvadorensis in different ecosystems, with the variations observed here being related to seasonality, resulting in differences between populations of the same species. In the second chapter of this dissertation, the objective of the work was to evaluate how seasonality and the ecosystem of occurrence influence the autoallelopathy exerted by the funicular pulp of the fruits of P. catingicola subsp. salvadorensis on the germination behavior of its seeds. The results for this chapter showed that the seeds produced in the rainy season, in both populations, presented higher germinability, shorter germination time and greater synchrony, with less uncertainty and variation in the germination process. However, the extracts of lower polarity (AcOEt and Hex) negatively influenced the germination behavior as the concentrations increased during the rainy season, for both populations. Therefore, we can conclude for this chapter that the effect of autoallelopathy is dynamic in nature, being influenced by the fruit production seasons and the ecosystem in which these populations are inserted. The results found in this dissertation provide a comprehensive view of the metabolic responses of this species to environmental conditions, highlighting its adaptive capacity and the role of seasonal conditions in directing its metabolism. In this context, extractions performed with different organic solvents revealed significant variations in the concentrations of compounds between seasons and populations, demonstrating that seasonality not only regulates metabolic synthesis, but also influences the distribution and predominance of metabolites, adjusting them to the environmental conditions of each period, influencing the autoallelopathic effect differently. 2025-02-04T00:00:00Z