Análise de micronúcleos em aves como ferramenta de biomonitoramento do efeito da poluição em ambientes florestais e urbanos

Abstract

Human activities impact the natural environment in many ways, often with negative consequences for the ecosystem. Environmental pollution is one of the biggest problems generated by these activities, as it has genotoxic characteristics that trigger anomalies, such as micronuclei. Birds are sensitive to environmental changes and may be useful as biomonitors, and it is interesting to unite the micronucleus technique with birds. The objectives were to verify if there is a difference in the micronucleus frequency of the birds captured in forest areas with different proximity to urban centers and between the dry and rainy seasons. Determine the frequency of micronuclei in captured bird species. To evaluate whether factors, life stage, biomass, body condition, sex, food guild and presence of ectoparasites interfere with the frequency of micronuclei. To analyze if bird populations present differences in micronucleus frequency between areas. To compare the micronucleus frequency of Belgian canaries kept in urban and rural areas and to verify if this frequency is related to the exposure time in a polluted environment. The study was carried out in six areas of semideciduous seasonal forests of Minas Gerais, grouped into: areas far from urban centers and highways (Água Fria and Galheiro), areas near urban centers and highways (Glória and São José) and areas inserted in centers urban and close to highways (Sabiá and Siquierolli). There were six capture campaigns per area from 2014 to 2018, using fog nets. After capture, the birds were removed from the nets, identified at species level, ringed, weighed and the tarsos haved measured. And it was verified age, sex and presence of ectoparasites. Body condition was assessed by Index Mass Relative (IMR) and species were classified in relation to food guilds. Belgian canary individuals were kept for 120 days in the city of Uberlândia and in a control area (rural). Blood was collected for two blood extensions per individual and 10000 erythrocytes per bird were analyzed. 1308 birds of 87 species with a total of 1403 micronuclei were captured. The frequency of micronuclei in birds varied among study areas, with lower values in distant cities and higher in cities. In the dry season the frequency of micronuclei in birds was significantly higher than in rain. The frequency of micronuclei varied among bird species, between food guilds, biomass and IMR and did not vary between age, sex and presence of ectoparasites. Five species were selected to be used as biomonitors, since they presented higher frequency of micronuclei in the most polluted areas. There was a significant difference in the frequency of micronuclei between Belgian canaries exposed in the city and the control area and the longer the exposure time the greater the frequency of micronuclei in the kept canaries in the city. Thus, we conclude that the micronucleus technique combined with birds becomes an excellent tool for biomonitoring of areas with pollution.