https://ri.ufs.br/jspui/handle/riufs/14820 Thu, 30 Apr 2026 18:56:16 GMT 2026-04-30T18:56:16Z http://ri.ufs.br:80/retrieve/6bd8ae9b-958d-462c-bc1d-836588c643c5/PPEC.jpg https://ri.ufs.br/jspui/handle/riufs/14820 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. Mon, 23 Feb 2026 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/24734 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. Thu, 27 Feb 2025 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/24155 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. Wed, 21 Feb 2024 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/24153 2024-02-21T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/24148 Título: Interpretações paleoecológicas e tafonômicas de mamíferos quaternários em depósitos de tanques do Centro-Norte da Bahia, Brasil Autor(es): Xavier, Márcia Cristina Teles Abstract: At the Brazilian Intertropical Region (BIR) the characteristic fauna was composed predominantly of megamammals and large mammals that lived until around nine thousand years before present (B.P.). Recent studies have increasingly demonstrated that the BIR would not be a totally homogeneous zone, presenting distinct niches and that the Pleistocene fauna would not be geochronologically restricted to the Late Pleistocene, but that it was also present during the Middle Pleistocene and reached the Holocene, a period in which they place the extinction of megafauna, according to the most accepted hypotheses. In this work we sought to understand the paleoenvironmental dynamics that occurred in fossiliferous outcrops of the tank type, located in the municipality of Jaguarari - Lajedo II site and in the municipality of Campo Formoso in the Toca do Novilho and Baixão sites, located in the Territory of Identity Piemonte Norte do Itapicuru in the Central - North portion of Bahia, in Caatinga domain. For this purpose, Pleistocene mammal fossils were collected for isotopic analysis ( 13C) in order to infer about the diet of these animals, determine the trophic niche of the species and identify the degree of overlap and competition for resources. Taphonomic signatures were identified and evaluated in the studied fossiliferous accumulations in order to perform a comparative study on a regional scale in the Center-North of Bahia, in order to explain the variations in signatures between tank deposits and thus understand the depositional history of the studied tanks. The fauna in Jaguarari was represented by seven taxa, three megamammals and four large mammals. Five taxa were grazers, one a ramoneer and one a predator, five generalists and two dietary specialists. At Toca do Novilho, 10 taxa were identified, four megamammals and six large mammals. Seven taxa were grazers; two ramblers and one predator, seven generalists and three dietary specialists. In Baixão 12 taxa were recorded, three megamammals; eight large mammals and one medium-sized mammal. Six taxa were grazers; two ramblers; one folivore; one omnivore and two predators, seven generalists and five dietary specialists. Regarding the taphonomic aspects, Lajedo II presents itself as an internally complex accumulation with a minimum temporal mixing rate estimated at ± 20 years. Toca do Novilho presents itself as an internally complex accumulation with a minimum temporal mixing rate estimated at ± 5 years. In these two tanks, hydraulic transport was the main taphonomic process in the deposit, producing a peripheral assemblage with a possible spatial mixing. Baixão presents itself as an internally simple accumulation with a minimum temporal mixing rate estimated at ± 8 years, with hydraulic transport as the main taphonomic process in the deposit, producing a peripheral assemblage with a possible synchronous accumulation. From the data obtained, it is suggested that Jaguarari and Campo Formoso present heterogeneous regions regarding vegetation and climate with differentiation of niches along their extension. The three deposits studied present similarities in terms of taphonomic aspects, when compared to other Quaternary tanks in Brazil. Mon, 27 Feb 2023 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/24148 2023-02-27T00:00:00Z