http://repositorio.ufc.br/handle/riufc/332 2026-04-08T15:18:25Z http://repositorio.ufc.br/handle/riufc/85398 Título: Efeito do uso e ocupação do solo sobre as variáveis limnológicas e a composição da comunidade em um rio intermitente Autor(es): Duarte, Maria Rita Nascimento Abstract: The consequences of human activities on water resources have had repercussions on theway and quality of life of populations and communities of aquatic organisms, affectingthe environmental balance of areas drained by hydrographic basins, thus contributing tochange their landscapes at local scales, regional and global. The Intermittent rivers arecharacteristic for their flow variability, due to alternations between the two extremes offlow, flooding and drying, which create complex mosaics of dry channels and lenticwaters. Intensive land use raises concerns about the threats posed by anthropogenichydrological changes to the ecological integrity of intermittent rivers. Given the context,our study aims to assess how land use and occupation influence limnological variablesand the composition of communities in an Intermittent River. In chapter 1, we evaluatedthe dynamics of the physical, chemical and biological variables of the waters of anintermittent river and of an artificial surface reservoir through multivariate analysis andin response to the use and occupation of the soils of its hydrographic basin. The studywas carried out in the Cruxati River watershed in four study areas (three river areas andone artificial reservoir) and the images were obtained from the Landsat-8 satellite OLIsensor. The limnological variables measured were: pH, electrical conductivity, dissolvedoxygen, turbidity, nutrients (total nitrogen and total phosphorus) and chlorophyll a.Limnological variables were analyzed using Principal Component Analysis - PCA,Tukey's test and Cluster Analysis. The eutrophication of the studied areas was calculatedusing the Trophic State Index. The PCA allowed the selection of three componentsindicating the quality of surface water, river and artificial reservoir, explaining 88.57%of the total variance. The limnological variables responsible for the grouping were:electrical conductivity; dissolved oxygen and turbidity. The use and occupation of thesoil influenced the water quality of the river stretches. Anthropization influenced thedissolved oxygen content and the presence of arable areas caused an increase in turbidity.However, the most conserved landscape (artificial reservoir) was the one with the highestdegree of eutrophication due to the difference in hydrological dynamics between lenticand lotic environments. In chapter 2, evaluated the historical effects of land use andoccupation on limnological variables and the composition of aquatic macroinvertebratesand fish in six Intermittent microbasins. For this purpose, land use and land cover mapswere made, as watersheds 4, 5 and 6 have been going through a process of intensedeforestation and an increase in non-vegetated and agricultural areas, adding an alert tothe compromise of environmental quality and to the management of water resources inthe semi-arid region. Tipo: Tese 2022-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85071 Título: Modelagem de distribuição da herpetofauna nos brejos de altitude do setor setentrional do semiárido brasileiro a partir do pleistoceno superior Autor(es): Holanda, Alyne Bezerra Tabosa de Abstract: The Brazilian semi-arid region, which encompasses the Caatinga biome, is situated betweentwo humid biomes—the Amazon Rainforest and the Atlantic Forest—and is characterized bythe occurrence of isolated humid environments that constitute important habitats for the localherpetofauna. This region experienced climatic shifts during the Quaternary, which influencedthe spatial distribution of humid forests. The present study examined the distribution ofherpetofaunal species groups adapted to humid enclaves within the Brazilian semi-arid regionusing species distribution modeling, focusing on the Last Interglacial (~120 ka), the LastGlacial Maximum (~22 ka), and the Mid-Holocene (~6 ka). Paleoclimatic data obtained fromWorldClim 1.4 were employed in the analyses. The models demonstrated strong discriminatoryperformance for the variables associated with each taxonomic group (maximum temperatureof the warmest month for lizards and snakes, and annual precipitation for anurans), in additionto high rainfall totals, which were relevant for all groups. Amphibians exhibited a greaterdependence on humid ecosystems, with their distributions being markedly affected during drierperiods. Lizards and snakes, in contrast, showed higher ecological tolerance, resulting inbroader distributions under these drier climatic scenarios. Overall, species distributionscontracted by approximately 35% (lizards) to 61% (snakes) during the Last Interglacial,whereas amphibians experienced a reduction of 73% relative to their current distribution. Tipo: Tese 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/80916 Título: Efeito da variabilidade ambiental na história evolutiva das angiospermas do semiárido brasileiro Autor(es): Paiva, Aparecida Barbosa de Abstract: The structuring of biological communities results from the dynamic interaction of multiple factors,such as speciation, dispersal, extinction, ecological interactions, and environmental filtering.However, most studies on these processes adopt isolated approaches, emphasizing either ecologicalmechanisms or historical processes. Integrating these perspectives remains a crucial challenge forunderstanding the factors shaping biodiversity. In this thesis, we aim to advance this understandingthrough two chapters that investigate the taxonomic and phylogenetic diversity patterns of woodyspecies in the Caatinga, analyzing how environmental variables, such as climate and soil, along withbiogeographic processes, influence the structuring of these communities. In the first chapter, weexplore the climatic and edaphic predictors that determine the diversity of woody species in thethree main geological substrates of the Caatinga (crystalline, karstic, and sedimentary). We alsoexamine the connections between these diversity patterns and adjacent areas of the Cerrado andAtlantic Forest, investigating the role of geomorphological landscapes in the diversification of theCaatinga’s woody flora. We calculated phylogenetic alpha diversity and taxonomic andphylogenetic beta diversity patterns for both woody and herbaceous species, considering theinfluence of climatic and edaphic variables. The results indicated that among the factors analyzed,only temperature significantly influenced the phylogenetic alpha diversity of herbaceous species. Incontrast, taxonomic and phylogenetic beta diversity were influenced by variables such as pH, cationexchange capacity, temperature, and precipitation. Furthermore, our findings revealed that diversityin the crystalline, karstic, and sedimentary substrates of the Caatinga is more similar among themthan to adjacent areas of the Cerrado and Atlantic Forest, highlighting the ecological uniqueness ofthe biome. In the second chapter, we adopted a phylogenetic approach to investigate how diversitypatterns relate to present and future projected climate conditions. Using different phylogeneticmetrics, we identified that both current and short-term future climate scenarios positively influencephylogenetic endemism. Additionally, we found that centers of neoendemism are associated withmilder conditions, such as lower temperatures and reduced precipitation seasonality, while centersof paleoendemism are linked to hotter and more seasonal conditions. These patterns suggest thathistorical events and long-term climatic variations have played a central role in the formation ofthese areas of endemism. The findings of this thesis emphasize the importance of integratinghistorical and ecological aspects to understand the mechanisms shaping the biodiversity of theCaatinga. Furthermore, they reinforce the potential of phylogenetic diversity as a tool for identifyingecologically significant areas and guiding conservation strategies, highlighting the need to preservekey regions for maintaining the biome’s biodiversity. Tipo: Tese 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/80694 Título: Impacts of land use on the dynamics, stocks and physical fractions of soil organic matter in tropical ecosystems Autor(es): Brito, Paulo Henrique Ferreira de Abstract: Soil organic matter (SOM) is a critical element for sustaining the fertility of tropical soils andaddressing climate change. However, the dynamics of SOM in response to changes in land useare still poorly understood, especially in highly threatened tropical ecosystems such as theAtlantic Forest. The main objective of this study was to evaluate the impact of different landuse systems on carbon (C), nitrogen (N) and sulfur (S) stocks and on the distribution of thephysical fractions of SOM, including particulate organic matter (POM), mineral-associatedorganic matter (MAOM) and dissolved organic matter (DOM), in representative areas of theAtlantic Forest in southeastern Brazil. The chapters of this work addressed the followingspecific aims: i) to review the theoretical framework and mechanisms governing the formation,persistence and dynamics of the physical fractions of SOM, highlighting knowledge gaps; ii)to quantify the stocks of C, N and S in different fractions of SOM at surface (0-5 cm) andsubsurface (50-60 cm) depths in different land use systems, including native forests, pasturesand agricultural crops; iii) to investigate SOM contents in order to understand the dynamics oforganic carbon and nutrient formation in tropical soils. The soils analyzed belong to the area ofthe Federal University of Viçosa (UFV), located in the Zona da Mata region of Minas Gerais,Brazil, with a tropical high-altitude climate (Cwa) and soils classified as typical dystrophicLatossolos Vermelho-Amarelos (Oxisols). Seven land-use systems were evaluated: nativeforest, Araucaria forest, Eucalyptus and rubber plantations, pasture, coffee and corn. Soilsamples were collected in representative trenches and subjected to analysis of the physicalfractionation of SOM, quantification of C, N and S stocks and chemical and physical soilcharacterization. The results showed that systems with perennial vegetation, such as nativeforests and Araucaria plantations, had higher stocks of C and N, especially in the more stablefractions (MAOM). On the other hand, agricultural systems, such as coffee and corn, resultedin lower SOM accumulation, especially in the more labile fractions (POM and DOM). Inaddition, C stocks in the subsoil were more homogeneous between the systems, suggesting thatsustainable management practices can mitigate carbon loss. This study contributes to theunderstanding of the impacts of changes in land use on the dynamics of SOM in tropicalecosystems and provides fundamental information for the development of public policies andmanagement practices that promote soil conservation, carbon sequestration and environmentalsustainability. Tipo: Tese 2025-01-01T00:00:00Z