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Dissertations |
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1
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Thayná Silva Batista
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Estimates of occupancy and detection of cougars (Puma concolor) in the Rio Doce State Park, Minas Gerais.
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Advisor : FERNANDO CESAR CASCELLI DE AZEVEDO
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BANKING MEMBERS :
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ADRIANO GARCIA CHIARELLO
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ANDRE FLAVIO SOARES FERREIRA RODRIGUES
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FERNANDO CESAR CASCELLI DE AZEVEDO
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Data: Apr 20, 2023
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Show Abstract
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The puma (Puma concolor) is a top predator with a wide geographic distribution, responsible for performing important ecological functions that help in the dynamics and integrity of ecosystems. Populations of this species are declining globally, often as a result of habitat loss and fragmentation and consequent anthropic changes in the landscape. Although is considered generalist, some factors may influence the selection of habitats by the specie. Thus, we aimed to evaluate the influence of environmental characteristics and anthropic factors on the probability of occupancy and detection of puma in the Rio Doce State Park (RDSP). For this, we used data collected through camera traps, in the period between 2016 and 2017. We also used specific covariates of the sampling period and sample sites to generate Single-season occupancy models. Our more parsimonious model indicates that puma occupation was better explained by distance from rivers, but none of the covariates had a strong influence on the estimates of this parameter. Detection, on the other hand, was better explained by the covariates distance from rivers, number of days sampled per occasion and rainfall per occasion, but only the last two showed a strong association with the probability of detection of the specie. Sampling effort was the main factor positively associated with the detection of puma, suggesting that longer-term surveys may make it possible to obtain a greater number of records of the specie, thus ensuring better performance of the models. The lower displacement of puma in the RDSP during the period of higher rainfall may be related to the increase in the abundance of prey during the rainy season. The lack of influence of most of the covariates analyzed for the occupation and detection of puma may reflect the good environmental quality of the RDSP. Although our results may suggest a positive scenario for the specie in the Atlantic Forest, the reality for other remnants of this biome may not be the same. Thus, the development of studies on a finer scale and that explore landscapes under different levels of protection may be necessary for a better understanding of the factors responsible for mediating the use of the habitat by puma.
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2
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Júlio César Andrade
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Spatial-temporal determinants of typical Cerrado areas in the Serra de São José.
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Advisor : GISLENE CARVALHO DE CASTRO
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BANKING MEMBERS :
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EVANDRO LUIZ MENDONÇA MACHADO
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GISLENE CARVALHO DE CASTRO
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JOSÉ ELVINO DO NASCIMENTO JUNIOR
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Data: Jun 30, 2023
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Show Abstract
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The Brazilian Cerrado is a vegetation whose distribution is determined by the interaction of various factors. The soil plays an important role in the dynamics of this domain, influenced by fertility and drainage. Additionally, human factors such as agricultural production and livestock, along with altitude and slope of the terrain, and biological invasions, mainly of exotic grasses, play a fundamental role. Fire is also essential in Cerrado dynamics, as many species depend on and are adapted to it. In this context, this study utilized geoprocessing and remote sensing tools to identify the main determinant variables that influence the dynamics of Cerrado vegetation sensu stricto in the Serra de São José, an important conservation area in the region due to the presence of two conservation units. The study revealed how the Serra has faced highly severe fires in the past twenty-two years, albeit with low frequency. It also demonstrates how the interaction of these fires with other determinant factors has been acting together to influence the dynamics of the communities of this phytogeographic formation present in the region.
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3
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ALINE ISABEL DIAS DINALLI
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Natural regeneration of hedgerows in Campo das Vertentes, MG.
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Advisor : GISLENE CARVALHO DE CASTRO
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BANKING MEMBERS :
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CLEBER JOSE DA SILVA
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EDUARDO VAN DEN BERG
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GISLENE CARVALHO DE CASTRO
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Data: Jul 28, 2023
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Show Abstract
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The hedgerows are ancient excavations made in the 17th and 18th centuries by enslaved individuals to separate land plots, and due to the lack of management in these environments after their creation, it allowed the vegetation to colonize through propagules from adjacent areas. Due to their concave structure, they possess a microclimate, structure, and floristic composition similar to forest interiors and play an important ecological role in regional conservation. Despite their potential, there had been no studies on the natural regeneration of these environments and their ability to sustain themselves, so this study aimed to examine the structure and diversity of two regenerating strata of shrub and tree species in four ecological corridors of valo in the Campo das Vertentes region. Seedlings ≥ 50 cm and ≤ 100 cm in height (small stratum) were analyzed in 4 m² plots, and seedlings > 100 cm in height and ≤ 5 cm in DBH - Diameter at Breast Height (large stratum) were analyzed in 40 m² plots. The DBH was measured, heights were recorded, and it was indicated in which section of the valo they were located (wall or bottom), botanical identification was conducted for all individuals that fit these parameters. Structural analysis was carried out using phytosociological parameters and floristic diversity of the species in each corridor for both the large and small strata. Additionally, the same parameters were analyzed for the species based on the section of the valo they occupied (wall or bottom). They were also analyzed based on their ecological group and their ability to regenerate in the presence or absence of light (shade tolerance). The floristic composition of the regenerating stratum was compared to the adult floristic composition previously evaluated by Miguel (2019) using dissimilarity tests.
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4
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ELAINE DOS REIS SILVA FERREIRA
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Invasion of exotic species around trails in the Libélulas da Serra de São José State Wildlife Refuge - MG
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Advisor : GISLENE CARVALHO DE CASTRO
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BANKING MEMBERS :
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LUCIANA BOTEZELLI
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GISLENE CARVALHO DE CASTRO
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JOSÉ ELVINO DO NASCIMENTO JUNIOR
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Data: Dec 4, 2023
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Show Abstract
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This study aimed to identify and evaluate the frequency and percentage of cover occupied by native and invasive exotic species (EEI) around 13 trails with cerrado physiognomies in the Libélulas da Serra de São José Wildlife Refuge - MG. 66 Sample Units were allocated to the investigated trails, each sampling unit is composed of 3 plots of 1.00 x 2.5 m, perpendicular to the edges. The number of Sampling Units per trail was proportional to the length of the trail within the Refuge, where individuals from the woody and herbaceous components were evaluated. The percentage of coverage for invasive and native alien species per trail was calculated by comparing the invaded coverage area in the edge, transition (6 m from the edge) and interior (12 m from the edge) sectors. There was no statistical difference in invasion between the sectors, finding invasion in 48.5% of the border plots, 50% of the transition plots and 48.5% of the interior plots. The percentage of coverage by EEI is affecting the richness of native species in the three sectors (F=0.0487, p= 0.9525), the higher the percentage of coverage by EEI the lower the average richness of native species. 2143 individuals distributed across 486 species were sampled, with EEI of 6 genera being identified: Agave, Eucalyptus, Melinis, Pinus, Psidium and Urochloa. Invasion by M. minutiflora occurred in 10.70% and Uruchloa spp. 5.93% of the investigated area, both species were detected in 10 trails.
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5
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KESSIN ÂNGELO GUIMARAES CABRAL
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Applicability of stereo-BRUV to estimate the size structure of Oligosarcus paranensis in the Mangue stream located in the Serra de São José
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Advisor : ANDREY LEONARDO FAGUNDES DE CASTRO
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BANKING MEMBERS :
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ANDREY LEONARDO FAGUNDES DE CASTRO
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FERNANDO CESAR CASCELLI DE AZEVEDO
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LUIZ GUSTAVO MARTINS DA SILVA
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RICARDO MACEDO CORRÊA E CASTRO
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Data: Dec 4, 2023
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Show Abstract
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The efficiency of data collection depends on the association between methodology and objectives. Methodologies can be of various types and may or may not require researcher involvement. In the field of ichthyology, especially in the realm of stream fish, there are numerous methods for collecting ecological information. One notable methodology is the BRUV (Baited Remote Underwater Video), which involves remote underwater video sampling using bait to attract fish into the camera's field of view. While it is a versatile methodology, extracting biometric information from video footage poses a significant challenge, particularly regarding size structure data of the filmed fish. Several proposals have been employed to enhance the extraction of size data, such as the use of specific configurations within the BRUV setup. One of these configurations involves the use of two cameras, known as stereo-BRUV, which requires calibration processes involving relatively expensive software or less expensive software but with a higher level of computational expertise. A recently emerged software has shown viability for such calibration and demonstrated efficiency in estimating fish sizes, as well as ecological data like species richness and abundance. One of the species requiring more detailed ecological data extraction is Oligosarcus paranensis, a species with a recognized distribution in the Mangue stream, within the Serra de São José. Consequently, the objective of this study was to assess the applicability of using stereo-BRUV for estimating the sizes of O. paranensis. To verify the software's functionality, 15 model fish were created in a laboratory, spanning sizes from 23.4mm to 148.3mm, measured with calipers and defined as the actual sizes. Each model fish was measured five times using stereo-BRUV, totaling 75 measurements. There was no statistical difference between the data, with an average absolute error of 2.3%. In the comparison of size structure, the comparison was made between the fish sizes obtained using the software and those captured with traps. Thirty 30-minute videos were collected at five points in the Mangue stream, with the stereo-BRUV structure deployed first for sampling, immediately followed by the traps. The mean and standard deviation of size between the capture methodology were 50.9mm ± 18.4mm, while for the individuals filmed, it was 60.3mm ± 17.2mm. There was sufficient evidence to suggest a statistical difference between the measurements. Smaller fish were more frequently captured in the traps, while larger fish appeared more often in the videos. Regarding the sampling points, the Mann-Whitney test showed differences between points 1, 2, and 3, which had statistically different size data compared to the fish sizes found at points 4 and 5. There was no difference between points 1, 2, and 3, and points 4 and 5. In terms of abundance, the videos recorded a total of 155 fish with an average of 5.1 fish, whereas the captured fish numbered 378 with an average of 12.6. At the sampled points 1, 2, 3, 4, and 5, the average number of individuals in the videos was 5.8, 7.8, 3.8, 4.3, and 4.0, respectively, while for the captures, the averages were 5.8, 8.1, 2.1, 27.8, and 19.0. Through the use of stereo-BRUV, a new parameter for assessing abundance was introduced, considering the maximum number of individuals viewed and identified in a short video segment (NMAX), added to other fish whose sizes were not already evident in the NMAX, referred to as NMAX+. NMAX+ improved abundance estimates by an average of 60%. However, concerning size estimation, there was not a statistically significant difference for the size structure estimate. In terms of antagonistic behavior among O. paranensis individuals, 46 events were observed during all the videos. There was a statistical difference between the sizes of fish that initiated attacks on those that fled. The correlation between the data showed a 50 percent size association, indicating that not only larger fish attacked smaller ones, but reversed cases were also identified by stereo-BRUV. The use of the stereo-BRUV methodology proved to be efficient in estimating fish size. It can be applied in stream environments and is highly recommended for conservation areas. Furthermore, the methodology can be employed in various other studies involving size and distance estimation, offering excellent precision in the results.
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6
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MARLUCE APARECIDA MATTOS DE PAULA NOGUEIRA
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Evaluation of susceptibility to barotrauma in two species of neotropical fishes.
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Advisor : ANDREY LEONARDO FAGUNDES DE CASTRO
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BANKING MEMBERS :
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ANDREY LEONARDO FAGUNDES DE CASTRO
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FERNANDO CESAR CASCELLI DE AZEVEDO
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GUILHERME SOUZA
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LUIZ GUSTAVO MARTINS DA SILVA
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Data: Dec 5, 2023
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Show Abstract
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Hydroelectric plants in Brazil, driven by abundant water resources, play a significant role in energy generation, but also pose threats to aquatic ecosystems and fish diversity in the Neotropical region. Rivers face threats due to the construction of dams and reservoirs, which lead to the fragmentation of river basins, causing negative impacts on fish fauna, such as: impaired migrations, exposure to predators, mortality and injuries due to mechanical shocks, turbulence, shear forces, cavitation, gas supersaturation and pressure variations can be caused by frequent exposure to turbines or spillways. Decompression, pressure variation or rapid pressure change during turbine passage, is one of the main threats to fish passing through plants. This can result in injuries, deaths and other sequelae, such as hemorrhages, exophthalmos, embolism, positive buoyancy, swim bladder collapse and changes in behavior. Impacting fish of different sizes and species, making it a growing concern in the operation of hydroelectric plants and machine maintenance. The present study evaluated the susceptibility of two species, the Lambari Astyanax bimaculatus and the Grumatã Prochilodus vimboides, to barotrauma, through simulation of decompression in the laboratory, in a hyperhypobaric chamber, under different pressure levels and different decompression rates. Identifying the occurrence of different types of injuries, such as: hemorrhage, embolism, fracture, exophthalmos, hypertrophied vessels and rupture of the swim bladder, caused by decompression. The experiments were carried out on 720 fish, 510 lambaris (Astyanax bimaculatus) and 210 grumatãs (Prochilodus vimboides), in three different experimental models. It is possible to confirm that the types of injuries are the same by varying the location and frequency, which allows a better understanding of the effects of decompression on these two species.
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