Maria Aparecida Lopes

Population structure of Eschweilera coriacea (DC.) S. A. Mori in forest fragments in eastern Brazilian Amazonia

A estrutura populacional de uma arvore de dossel comum na Amazonia oriental foi examinada em tres areas para investigar possiveis efeitos da fragmentacao da floresta. Evidencias para a hipotese de escape referente a sobrevivencia diferenciada de sementes/plântulas foram avaliadas. Duas parcelas amostrais de um hectare foram estabelecidas em cada area e todos os individuos de Eschweilera coriacea (DC.) S. A. Mori acima de um metro de altura foram marcados, medidos e mapeados. Individuos menores foram registrados da mesma maneira em subparcelas. Individuos maduros foram abundantes em todas as areas com densidades de 32-52 ha-1. A especie exibiu regeneracao substancial, embora a densidade populacional tenha variado quatro vezes entre as areas (1.256-4.805 individuos ha-1). Em geral, jovens apresentaram-se agregados enquanto adultos eram distribuidos aleatoriamente. A diferenca no padrao de dispersao de adultos e jovens deu suporte a hipotese de escape. Entretanto, nenhuma diferenca na estrutura da populacao entre as areas pode ser relacionada a fragmentacao da floresta.

Polyspecific associations between squirrel monkeys (Saimiri sciureus) and other primates in eastern Amazonia

One of the most common types of polyspecific association observed in Neotropical primate communities is that between squirrel monkeys (Saimiri) and capuchins (Cebus). The present study focused on association patterns in two Saimiri sciureus groups in eastern Brazilian Amazonia, between March and October, 2009. The associations were analyzed in terms of the species involved, the degree of association, and niche breadth and overlap. The study involved two S. sciureus groups (B4 and GI) on the right and left bank of the Tocantins River, respectively, within the area of the Tucuruí reservoir in southeastern Pará. Relations between species were classified as associations (individuals within 50 m and moving in the same direction), and encounters (individuals within 50 m and no coordinated movement). Group B4 was in association with Cebus apella during 100% of monitoring, and with Chiropotes satanas in 20.2%. By contrast, Group GI associated with Cebus 54.8% of the time, and with Chiropotes utahickae 2.5%. Encounters with Alouatta belzebul and Saguinus niger were recorded at both sites, with Aotus azarae and Dasyprocta prymnolopha at B4, and with Callicebus moloch, Dasyproct aleporina, Mazama gouazoubira, and Nasua nasua at GI. Overall, Saimiri had a broader niche than Cebus in terms of vertical spacing and diet, but not for substrate use. This pattern did not appear to be affected by association. While group GI spent significantly (P<0.05) more time in association with Cebus during the wet season, group B4 associated with Chiropotes more during the dry season. Despite the higher association rates, niche overlap was greater for all variables at B4. This may reflect differences in the ranging and foraging patterns at the two sites, and the varying potential benefits of association for Saimiri. Am. J. Primatol. 73:1145–1151, 2011.

Hierarchical structure and the influence of individual attributes in the captive squirrel monkey (Saimiri collinsi)

The dominance structure of primate social groups varies widely. In addition to the groups’ composition, intrinsic attributes such as sex, body size and life experience are important factors that can affect hierarchical dominance relations. All primates are social animals, and the social environment has a direct influence on the physiological conditions of vital systems such as immunological, reproductive and cardiovascular systems. In this study, we analyze the hierarchical structure of Saimiri collinsi in captivity, including the hierarchical structure type, the influence of individual intrinsic characteristics (sex, age, weight and origin—born in captivity or in the wild) based on the prior-attributes model, the relation between agonistic behavior frequency and hierarchical position, and hierarchy steepness, which represents the dominance gradient. We found that the group order was characterized by a partial hierarchy: a dominance position could be occupied by more than one individual simultaneously, including individuals of both sexes. Intrinsic characteristics had no influence on hierarchical structure, with the exception of the male in the highest hierarchical position, which had a markedly larger body than all other group members. Thus, the prior-attributes model did not apply to hierarchical formation of S. collinsi in captivity. Only the frequency of agonistic behavior of males correlated with their hierarchical position, and they differed from all other group members in their more aggressive behavior. The steepness between adjacent positions along the dominance gradient was significant only between the dominant male and the next individual in the group, with a smooth gradient between the other positions in the rank. As the access to resources is directly related to hierarchical dominance, a smooth dominance gradient is to be expected in species that form very large groups, such as wild Saimiri populations.

The tree species pool of Amazonian wetland forests: Which species can assemble in periodically waterlogged habitats?

We determined the filtered tree species pool of Amazonian wetland forests, based on confirmed occurrence records, to better understand how tree diversity in wetland environments compares to tree diversity in the entire Amazon region. The tree species pool was determined using data from two main sources: 1) a compilation of published tree species lists plus one unpublished list of our own, derived from tree plot inventories and floristic surveys; 2) queries on botanical collections that include Amazonian flora, curated by herbaria and available through the SpeciesLink digital biodiversity database. We applied taxonomic name resolution and determined sample-based species accumulation curves for both datasets, to estimate sampling effort and predict the expected species richness using Chao’s analytical estimators. We report a total of 3 615 valid tree species occurring in Amazonian wetland forests. After surveying almost 70 years of research efforts to inventory the diversity of Amazonian wetland trees, we found that 74% these records were registered in published species lists (2 688 tree species). Tree species richness estimates predicted from either single dataset underestimated the total pooled species richness recorded as occurring in Amazonian wetlands, with only 41% of the species shared by both datasets. The filtered tree species pool of Amazonian wetland forests comprises 53% of the 6 727 tree species taxonomically confirmed for the Amazonian tree flora to date. This large proportion is likely to be the result of significant species interchange among forest habitats within the Amazon region, as well as in situ speciation processes due to strong ecological filtering. The provided tree species pool raises the number of tree species previously reported as occurring in Amazonian wetlands by a factor of 3.2.

Translations of Chapter Summaries

Analise cladistica das sequencias dos genes Epsilon-globin a e IRBP fornece informacāe complementar importante para urn esboco das principais linhas da filogenia dos macacos do Novo Mundo. As abordagens morfologicas e de genetica molecular sao razoavelmente consistentes com as evidencias disponiveis atraves do reg istro fossil , significando que as formas modernas fornecem uma boa base para o desenvolvimento de uma classificācao dos platirrineos, e que o entendimento das relacōes entre fosseis podem ser facil itados com a inclusao dos generos viventes nas analises. Os estudos moleculares e morfologicas fortalecem a ideia de tres grandes grupos modernos, possivelmente divergindo num intervalo de tempo relativamente curto . Considerando as discordâncias nos estudos da sistematica de platirrineos nas ultimas decadas - a correta localizacoo filogenetica de Cebus, Saimiri, Aotus e Callicebus - a cornbina#x00E7;oo das evidencias colocam Callicebus definitivamente como parente dos pitecineos. Elas reforcam tambem a ligacoo entre Saimiri e os calitriquineos, o elo entre Cebus e Saimiri, e sua associacoo com calitriquineos como uma linhagem monofiletica do grupo dos «cebideos». Os dados de DNA divergem, porem, com a colocacoo de Aotus como uma linhagem basal desse agrupamento, urn achado inconsistente com as evidencias morfologicas. A analise de DNA tambem aponta a necessidade de uma reconsideracoo da taxonomia do genero Callitrhix, que talvez noo seja monofiletica. Os dados confirmam parcialmente o padroo de ramificacoo do clade dos atelideos, posicionando Alouatta como a linhagem mais velha. Problemas que permanecem dentro dos calitriquineos e atelineos incluem: 1)os afinidades precisas entre os atelineos, Lagothrix, Ateles e Brachyt eles; e 2) a sequencia de ramificacoo dentre os calitriquineos, i.e., Callithrix/Cebuella, Leontopithecus , Saguinus e Callimico.