Determinantes ambientais da densidade de Callicebus coimbrai em fragmentos florestais no nordeste brasileiro e implicações para a sua conservação

• Ano de defesa: 2013
• Autor(a) principal: Hilário, Renato Richard
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraí­ba; Brasil; Zoologia; Programa de Pós Graduação em Ciências Biológicas; UFPB
• Palavras-chave em Português: Mata Atlântica; Estrutura da Vegetação; Extinções locais; Palmeiras; Bromélias; Cipós; Atlantic Forest; Forest Structure; Local Extinction; Palms; Bromeliads; Lianas; CNPQ::CIENCIAS BIOLOGICAS::ZOOLOGIA
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/tede/4121

Natural environments vary considerably around the globe, due to many factors, such as climate, topography, soil composition and structure, and human interference. Understanding how these factors interact with the local biota is a main goal of ecologists. This thesis investigates how physical variables (climate and topography) influence forest structure and the abundance of four plant groups (bromeliads, bamboos, lianas, and palms), and the interaction between these biotic variables. The principal objective of the thesis was to evaluate the influence of environmental variables on the density of titi monkeys (Callicebus coimbrai) within the species' range, which corresponds to the Atlantic Forest between the São Francisco and the Paraguaçu rivers, in the northeastern Brazilian states of Bahia and Sergipe. Twenty-two forest fragments were surveyed during fieldwork and 19 of them were inhabited by titi populations. Components of forest structure, the abundance of bromeliads, bamboos, lianas, and palms, three climatic variables, fragment size, mean elevation, and the presence/absence of capuchin monkeys (Cebus xanthosternos) were recorded for each fragment. The densities of titis and marmosets (Callithrix jacchus) were estimated through the playback method. The larger fragments presented more mature forest structure. Rainfall and topography also influenced the forest structure. Lianas were more abundant in areas with lower rainfall, which is related to a competitive advantage of these plants in drier environments. Bromeliads were also more abundant in environments with less rainfall, but depended on a more even distribution of rainfall. Palms occurred at higher density in areas of late successional forest, which may be related to the occurrence of species that demand preserved habitats. None of the variables were correlated with the abundance of bamboos. The present study found that the fragments with highest titi densities are located in southern Sergipe. Forest with closely spaced and thicker trees, denser understory, and a greater abundance of lianas had higher densities of titi monkeys. These characteristics correspond to forest in late succession and to greater food availability for titis. During fieldwork, the presence of C. coimbrai could not be confirmed at four sites where the species had been recorded previously. Based on the response rate of the species in fragments where it was present, the probability that C. coimbrai would not respond to the playback was estimated at between 0.000177 and 0.0604. Low original density, together with the small size of some fragments and anthropogenic disturbance, may have been the causes of the extinctions. The extinction of titi populations was also suspected at two other sites where less systematic playbacks were not responded to, and local residents confirmed the absence of the species. At three other sites where C. coimbrai had occurred, the forest had been cleared completely. All these populations were lost within the past ten years and represent up to one fifth of the total area occupied by C. coimbrai.