http://repositorio.ufc.br/handle/riufc/324 2026-05-25T06:55:34Z http://repositorio.ufc.br/handle/riufc/86435 Título: Análise geoquímica de micronutrientes metálicos e aplicação de índices de risco ecológico em solos de áreas suscetíveis à desertificação no Jaguaribe, Ceará Autor(es): Oliveira, Eryc Jefferson Alves de Abstract: This study evaluated the availability of metals and the associated ecological risk in soils withdifferent degrees of degradation in a desertification-prone region in the municipality ofJaguaribe, Ceará State, Brazil. Three areas representing distinct stages of degradation wereselected: control area (CA), recovering area (RA), and degraded area (DA). In each area, threecomposite soil samples were collected at a depth of 0–20 cm, totaling nine samples. Eachsample was analyzed in triplicate in the laboratory to determine its physicochemical propertiesand the concentrations of B, Cu, Fe, Mn, Mo, Ni, and Zn. Metal concentrations were obtainedby partial acid digestion according to the EPA 3051A method and expressed as pseudo-totalconcentrations. Potential ecological risk was assessed using quantitative indices:Geoaccumulation Index (Igeo), Pollution Index (PI), Enrichment Factor (EF), and PollutionLoad Index (PLI). Statistical analyses were performed to evaluate the influence of independentvariables (soil degradation degree: DA, RA, and CA; and soil physicochemical attributes, suchas pH and organic matter) dependent variables corresponding to metal concentrations. Thisanalysis included normality tests, ANOVA, Kruskal-Wallis, and Spearman correlation. Ingeneral, soils from the degraded area showed lower concentrations of essential metals, exceptfor Fe, which presented higher levels in the degraded area, possibly due to the accumulation ofiron oxides in the clay fraction. Ecological risk indices indicated the absence of significantanthropogenic contamination, with values classified as non-polluted or minimally enriched.Significant correlations between Cu and B with organic matter, and between Ni and Zn withpH, suggest that the dynamics of these metals are strongly influenced by these soil attributes,affecting their availability and retention. The results obtained may support decision-makingregarding the management and recovery of degraded areas in semi-arid regions susceptible todesertification. Tipo: Dissertação 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85766 Título: Atividade e diversidade da biota do solo em agroecossistemas regenerativos e convencionais Autor(es): Silva, Hugo Felipe da Abstract: Sustainability of agroecosystems requires changes in agricultural practices that integrate soil biodiversity as a central component, with regenerative (conservationist) practices representing an alternative for coffee production systems. In this context, the present study evaluated biological diversity and its association with coffee production systems under conventional, organic and regenerative management, in areas with contrasting levels of yield: low (LY: 2,148- 3,372 kg ha⁻¹) and high (HY: 2,520-5,360 kg ha⁻¹) in the Cerrado. In this study, indicators of soil microbiota, carbon (C) and nutrients were evaluated, as well as metataxonomic analyses of bacteria and fungi. In addition, soil fauna was assessed using pitfall traps during the dry and rainy seasons. Conventional management showed higher microbial activity and β-glucosidase activity, as well as greater microbial biomass and microbial quotient, whereas regenerative management showed higher urease activity. Bacterial richness in the rhizosphere was higher under conventional management compared with regenerative management and was greater than that observed in Cerrado vegetation and in bulk soil. In contrast, fungal richness and soil macrofauna were higher in natural vegetation, and regenerative management showed greater soil fauna richness than conventional management, which presented the lowest diversity values. With regard to coffee yield under regenerative management, high positive correlation coefficients were found between yield and the microbial quotient, acid phosphatase activity and the rhizosphere C:N ratio, as well as between the Z score of surface soil biological activity and the rhizosphere effect. Conversely, yield showed high negative correlation coefficients with soil carbon and nitrogen contents and with labile carbon. Areas with lower yield showed reduced fungal richness in the rhizosphere and in bulk soil, whereas increased yield was associated with denser and more connected networks, in contrast to the pattern observed for bacterial networks. Differences in yield levels were also reflected in soil fauna, with higher richness and diversity of arthropods and greater abundance of predators (Opiliones and Araneae), and lower abundance of Formicidae, in areas of high coffee yield. Biodiversity (bacteria, fungi and arthropods) was affected by management and was associated with higher and lower levels of coffee yield in the Cerrado. Tipo: Tese 2026-01-01T00:00:00Z 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