Banca de DEFESA: FABIANA OLIVEIRA DE AMORIM
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.DISCENTE : FABIANA OLIVEIRA DE AMORIM
DATA : 31/05/2019
HORA: 14:00
LOCAL: PAF I, Sala 121 - UFBA
TÍTULO:
Batrachochytrium dendrobatidis (Fungi: Chytridiomycota) in amphibians in the state of Bahia, Brazil: distribution and relationship with the environment.
PALAVRAS-CHAVES:
Anurans, Chytridiomycosis, Emerging Infectious Disease, Extinction, Populations Decline
PÁGINAS: 126
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:
Amphibians are considered the most endangered vertebrates. Among the main causes are habitat fragmentation and climate change. Infectious diseases are considered as important threats to amphibians, especially chytridiomycosis caused by the fungus Batrachochytrium dendrobatidis (Bd). However the distribution of this fungus in the neotropical region is still little known. In Brazil, its occurrence records are restricted to some regions, most of them in the Atlantic Forest. We investigated the occurrence of Bd in species of anuran amphibians of Atlantic Forest, Caatinga and Cerrado biomes in Bahia state. We present an updated analysis of the Bd distribution in Bahia state, and evaluated the environmental variables related to its occurrence, through a Logistic Regression model. We used two methods to identify the fungus, a histological and a molecular (qPCR). Through the histological method, we analyzed 190 skin samples from 85 species of anurans preserved in cientific collections. Through the molecular technique, we analyzed the material extracted from the epidermis of 245 specimens of amphibians collected in natural environments. A total of 104 species of amphibians were analyzed. Aiming to understand the distribution pattern of Bd in the state of Bahia, we performed the potential distribution modeling of the species. We used the MaxEnt 3.4.1 algorithm to generate the model, based on the Bd records for the state of Bahia.We recorded 50 cases of infection in 30 species of amphibians. Of the positive cases, 72% were from the Atlantic Forest. We recorded seven new species infected for the first time with Bd. We extend the Bd distribution approximately 276 km to the west and 210 km to the north in the state's Atlantic Forest. The number of infected species was positively correlated (R = 0.98, p> 0.001) with the species richness of anurans per family. The variables that interfered in the occurrence of Bd were annual mean precipitation, seasonality of precipitation, seasonality of temperature and annual thermal amplitude. The potential distribution modeling presented high predictive performance, and predicted a large area of occurrence of the fungus on the coast of Bahia, with points in the south-central region of the state. The variables that most influenced the model were Precipitation of the driest quarter (56.3%), Minimum temperature of the coldest month (17.4%) and Precipitation of the hottest quarter (14.5%). More than 50% of the area is comprised of priority areas for conservation and 20% of conservation areas. About 80% of the Conservation Units inserted in the predicted area show high environmental suitability (≥0.7) for Bd. We reinforce the hypothesis that Bd is widespread in the Atlantic Forest and we suggest its dissemination in the other biomes of the state. Conservation efforts should involve long term studies to provide information on the dynamics of the infection, its relationship with the host, and effects on amphibian populations. Thus, we suggest the monitoring of amphibian communities in these areas, in order to minimize the consequences of infection.
MEMBROS DA BANCA:
Presidente - 007.104.978-90 - FLORA ACUNA JUNCA - USP
Interno - 1658906 - ADRIANA OLIVEIRA MEDEIROS
Externo ao Programa - 1349793 - MARCELO FELGUEIRAS NAPOLI
Externo à Instituição - FELIPE SILVA FERREIRA
Externo à Instituição - MIRCO SOLÉ KIENLE