Banca de DEFESA: PATRÍCIA FARIAS ROSAS RIBEIRO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : PATRÍCIA FARIAS ROSAS RIBEIRO
DATA : 31/08/2017
HORA: 13:30
LOCAL: Sala de reuniões do Centro de Biociências
TÍTULO:

The Neotropical Otter (Lontra longicaudis) in Northeastern Brazil: geographic distribution and conservation. 

PALAVRAS-CHAVES:

Mustelidae; Lutrinae; Semiaquatic; River Basins; Caatinga; Occurrence; Detection; Conservation

PÁGINAS: 80
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:

The geographic distribution of a species is an essential information for conservation planning. This information, however, is often biased towards some regions or taxonomic groups, according to accessibility of sampling sites and natural history of studied species. Lontra longicaudis is a little studied species because of its elusive behaviour and consequent low detectability in natural environments. This situation is worse in northeastern Brazil, which for a long time appeared as a gap in L. longicaudis distribution maps. This project aimed to understand how L. longicaudis is distributed in northeastern Brazil, one of the priority actions for its conservation. This was the first specific otter survey in the region, conducted through well-designed field campaigns to 17 river basins of northeastern Brazil, in the area north of São Francisco River, between Alagoas and Piauí states. Each river basin was sampled at three stretches (lower, middle and upper courses), over about 5 km, repeatedly for four days each, looking for evidences of species presence. This amounted to an overall sample effort of 726 km in 45 sampled river stretches. In the first chapter we discuss L. longicaudis occurrence in Caatinga, a semi-arid biome where a single record of the species occurrence was reported in the literature, and which has not been considered as part of its distribution in conservation planning and strategies. We report historical and current new occurrence records of L. longicaudis in Caatinga, discuss factors that may be influencing its occurrence in the region, and propose updating the species distribution map, based on the confirmation of a real gap in its current distribution. In the second chapter we analyze environmental, climatic and anthropic factors influencing otter occupancy and habitat use on river basins of northeastern Brazil, using an occupancy-based approach and generalized liner mixed models. Detection probability of otter’s signs was high and negatively influenced by river order. Precipitation seasonality was the main determinant of L. longicaudis occupancy in the region, which is concentrated in the subregion of the river basins draining to east, where the precipitation seasonality is lower, corroborating the previously reported absence of the species in river basins totally inserted in Caatinga. This climatic variable was also important for habitat use by the species, which was more intense in lower seasonality areas, corresponding to the Atlantic forest. Northeastern Atlantic forest is the least conserved portion of this biome. In this region, otters used more rivers with lower water catchment area upstream, which correspond to smaller tributaries, providers of better environmental conditions than main rivers, being as a refuge for the species. Even using refuges, the intensity of habitat use was negatively correlated with the percentage of natural remnants, an indirect consequence of the degradation status of the most frequently used areas by the species, placing L. longicaudis in a risk status in the region. In order to understand how the northeastern Brazil otter populations is structured and contribute to its long-term persistence, in the third chapter we analyze the species genetic diversity and gene flow in the region through mitochondrial DNA and analysis of five alternative dispersal scenarios (Euclidian distance, distance through watersheds, high land dispersal cost, land dispersal cost related to distance to river, land dispersal cost related to slope). 36 noninvasive samples (fresh faeces/mucus), from seven river basins, were analyzed. Of these, 17 amplified the three mitochondrial DNA segments analyzed, and were considered distinct individuals according to sampling locality and genetic composition. These individuals are representatives of seven haplotypes, from which four were identified for the first time in this study. Estimates of genetic variability indicate high haplotype diversity whereas presenting low nucleotide variability. The greatest genetic differentiation among samples were observed in two samples from Piauí, geographically above the Caatinga area were the species absence was confirmed in this study, confirming the climatic barrier through which gene flow can had been interrupted for longer time. In spite of being semiaquatic, the dispersion scenario most correlated with genetic differentiation among sampled individuals was the high land dispersal cost scenario, emphasizing a great dependence of the species on the aquatic environment. Least cost path analyzes indicate the São Francisco River as an important dispersal route connecting coastal river basins of northeastern Brazil with basins located north of the Caatinga, which highlights the importance of São Francisco river basin conservation.

 

MEMBROS DA BANCA:
Presidente - 1678338 - ADRIAN ANTONIO GARDA
Interno - 1678202 - CARLOS ROBERTO SORENSEN DUTRA DA FONSECA
Externo à Instituição - DIEGO ASTÚA DE MORAES - UFPE
Externo à Instituição - RENATA PARDINI - USP
Interno - 1863735 - RENATA SANTORO DE SOUSA LIMA MOBLEY