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Banca de DEFESA: BRUNO RAMOS BRUM

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : BRUNO RAMOS BRUM
DATA : 30/07/2022
HORA: 14:00
LOCAL: ENSINO REMOTO EMERGENCIAL
TÍTULO:

The Resilience of Birds in the Face of Environmental Pollution

PALAVRAS-CHAVES:

insectivorous birds; Pesticides; Bioindicators; Ecotoxicology; Mercury; wetland.

PÁGINAS: 117
GRANDE ÁREA: Ciências Biológicas
ÁREA: Biologia Geral
RESUMO:

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Texto de origem

Rapid human-induced environmental changes pose the greatest threats to wildlife populations and encompass many environmental disturbances, including habitat loss, introduction of exotic species, climate change, and contamination by fertilizer and pesticide applications from the complex production chain of the world. agribusiness, which in turn leads to an increase in the accumulation of metals such as mercury in water and soil. The exposure of non-target organisms to these chemical compounds is quite common, resulting in numerous cases of acute poisoning in the wild population, particularly in birds, which have low levels of detoxifying enzymes, increasing their sensitivity. Due to their persistence in the environment and their ability to bioaccumulate and bimagnify, both pesticide multiresidues and mercury have been associated with the decline of bird populations in different parts of the world. In this way, birds have played an important role as environmental bioindicators, and different species can be useful due to their different capacities for bioaccumulation. Recent studies indicate that the availability of multi-residues of pesticides and mercury can be increased in areas where there are water level fluctuations and vegetated habitats that experience wet and dry cycles during the year. Thus, areas such as the Brazilian Pantanal, which has these characteristics, are predisposed to be hotspots of avian exposure to these toxic compounds. Therefore, we present in chapter 1 a scientometric research on the impacts of pesticides used in agriculture over 21 years on insectivorous, insectivorous birds. 16 works were found, distributed in nine countries, including 50 species of birds classified in four categories of population status. In addition, the results showed that these birds had at least one organ/tissue/structure (liver, feces, stomach bolus, blood plasma, muscle tissue, food items, eggs) contaminated by one of the 21 types of chemical compounds presented in the analyzed articles, that directly affect their survival. Insectivorous birds that inhabit riparian forests of floodplains, by preying on invertebrates, tend to extend the length of their food chains, increasing the opportunity for biomagnification of chemical compounds in their organism. Knowledge about trophic ecology and partitioning of food resources by insectivorous birds is of great scientific importance. Thus, in the second chapter, we investigate trophic relationships through analysis of the partition of food resources between insectivorous bird species from a longitudinal gradient of riparian forest, in the northern portion of the Pantanal of Mato Grosso. Specimens were captured with a mist net using a sequence of 9 nets measuring 9m x 2m, mesh 36mm, which remained open for 4 continuous hours. A total of 126 specimens belonging to 14 species were collected. The food items most consumed by the birds sampled were insects belonging to the order Coleoptera, Hyminoptera-Formicidae, Hymenoptera, Diptera, Ixodida and Hymenoptera non-Formicidae, respectively, indicating a greater generalization of the studied species in terms of food exploitation. Finally, in the third chapter, we present the first work using insectivorous birds from the North Pantanal as bioindicators of exposure to mercury, with the objective of knowing the pattern of accumulation of this metal in different organs (muscle, liver and brain) and feather. A total of 218 specimens were collected and the samples were analyzed by direct analysis atomic absorption spectrometry (DMA-80). The mercury concentrations presented values in increasing order, muscle < brain < liver < feather, regardless of the collection site, with a variation in the mean of mercury concentrations from (0.07 to 0.27 µg.g-1), ( 0.04 to 0.62 µg.g-1), (0.14 to 0.81 µg.g-1) and (0.77 to 3.49 µg.g-1), respectively. Along the gradient, the Kruskal-Wallis test revealed significant differences between the concentrations in the tissues where muscle (KW = 73.88 p < 0.001), brain (KW = 100.23, p < 0.002), liver (KW = 65, 42, p < 0.009) and feather (KW = 39.52, p < 0.005) so that the concentration of mercury in the tissues of insectivorous birds increases following the direction of the watercourse, from the points upstream of Porte Estrela and Barra do Downstream buggy, Taiamã. Our results show that mercury is present in food webs in the Pantanal North of Brazil and can biomagnify in significant concentrations not only in predatory piscivorous species, but also in insectivorous birds in the studied region.

MEMBROS DA BANCA:
Presidente - 83200001 - AUREA REGINA ALVES IGNACIO
Externo à Instituição - DÉBORA FERNANDES CALHEIROS - EMBRAPA
Interno - 118188001 - ERNANDES SOBREIRA OLIVEIRA JUNIOR
Externo à Instituição - INAJÁ FRANCISCO DE SOUSA - UFS
Interno - 110049004 - MARIA APARECIDA PEREIRA PIERANGELI
Externo à Instituição - RENATO ZANELLA - UFSM

Notícia cadastrada em: 07/06/2022 10:05