Banca de DEFESA: LETICIA GURGEL BEZERRA MEDEIROS CAVALCANTI

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LETICIA GURGEL BEZERRA MEDEIROS CAVALCANTI
DATE: 05/05/2025
TIME: 14:30
LOCAL: Google Meet
TITLE:

Lizards and ecosystem services: Phyllopezus pollicaris (Spix, 1825) as a Bioindicator of Exposure to Natural Radioactivity in a semiarid region of Northeastern Brazil

KEY WORDS:

Squamata; Ecological functions; Ionizing radiation; Caatinga, Biological indicator

PAGES: 90
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUMMARY:

The use of animals as bioindicators has proven to be relevant for assessing the effects of ionizing radiation, and among reptiles, Testudines and Crocodylia have stood out. Lizards, although less studied, have characteristics that make them sensitive to environmental changes. In Brazil, there are large reserves of uranium, especially concentrated in regions such as Seridó in Rio Grande do Norte and Paraíba, with high levels of natural radiation. A study with lizards in this region identified Phyllopezus periosus as a good bioindicator due to the detection of genetic damage caused by radon. Considering that reptiles play essential roles in identifying environmental damage and maintaining ecosystems, we sought to evaluate whether the lizard Phyllopezus pollicaris, which has greater environmental plasticity than its congener, P. periosus, is also sensitive to natural radioactivity, with possible changes in its DNA, as well as to identify the ecosystem services performed by lizards. In this context and perspective, the general objective of this study was to qualitatively and quantitatively analyze the patterns and genotoxic effects of radioisotope contamination in Phyllopezus pollicaris and, at the same time, identify and evaluate the ecosystem services provided by lizards worldwide. To evaluate the sensitivity of P. pollicaris, slides with blood smears from specimens collected during a previous study were analyzed in three municipalities in Rio Grande do Norte, in the Seridó region, namely, Lajes Pintadas, Currais Novos and Serra Negra do Norte, all with high levels of ionizing radiation. For comparisons in terms of radiation levels, fieldwork was carried out in the RPPN Mata Estrela, in the municipality of Canguaretama/RN, which has low levels of natural radioactivity, to collect specimens of P. pollicaris, which were acclimated in the laboratory and from which blood was taken and blood smears performed. All blood smears from all specimens from all studied locations were analyzed and their erythrocytes were evaluated using the micronucleus test. In order to identify and categorize the ecosystem services provided by lizards worldwide, over the last 15 years, bibliometric research was conducted in three academic databases and the results were organized and categorized according to the different ecosystem service functions reported for reptiles. The results obtained demonstrate that P. pollicaris is sensitive to Radon, but its environmental plasticity does not result in increased DNA damage, and the formation of micronuclei is related to high natural radiation rates. The main categories of ecosystem services for reptiles were also identified: Provision and Regulation, in addition to Cultural services, due to the great importance of these animals as a food resource and cultural appeal. This study, therefore, highlights the lizard P. pollicaris as an indicator of environmental changes that directly affect human health, such as radioactivity, responsible for causing diseases such as lung cancer, in addition to the ecological importance of lizards and the relevant role they play in nature, whether through their cultural contribution and/or source of protein.

COMMITTEE MEMBERS:
Externo à Instituição - CARLOS EDUARDO ALVES SOARES
Presidente - 1121066 - ELIZA MARIA XAVIER FREIRE
Externo à Instituição - LEONARDO BARROS RIBEIRO - UNIVASF