The concept of pollination syndromes has been widely questioned, since plant–pollinator interactions have proved to be more generalist than was previously thought. We examined whether the network of a tropical high‐altitude grassland contained groups of plants and pollinators that interact preferentially with each other. A general binary matrix was created. To assess the robustness of myophily, in all analyses we considered: 1) the whole network, 2) the network after the wasps were removed, and 3) the network after the flies were removed. For each network we evaluated whether: 1) the observed interactions were more related to syndromes than expected by chance, compared to an expected matrix; 2) there was a modular structure; 3) the modules found were more related to syndromes than expected by chance, compared to another expected matrix; 4) the syndromes were equally robust. For this analysis, the general matrix was subdivided into smaller matrices that included each pollination syndrome separately. To test the influence of the functional groups of pollinators and the phylogeny of plants, in addition to the general matrix, we also considered the first expected matrix, a quantitative functional group and a plant phylogeny matrix. The pollination syndromes determined the pattern of interactions in the network: 69% of the total interactions resulted from the functional group of pollinators predicted by the plant syndrome. The network showed greater modularity (13 modules) than expected by chance, mostly consisting of the expected functional groups of pollinators and plant syndromes. The modules were associated with pollination syndromes more than was predicted by chance. Most of the variation in interactions was explained by functional groups of pollinators or by plant syndromes. Plant phylogeny did not account for a significant amount of variation in the interactions. Our findings support the concept of pollination syndromes. However, the interactions were not equally predicted by different pollination syndromes, and the accuracy of the prediction was strongest for ornithophily and melittophily.

Ocotea porosa has been extensively exploited over the past few decades because of the quality of its wood. Today, populations are reduced and the species is now included in the Red List of threatened species by the International Union for Nature Conservation. For conservation and management purposes, it is extremely important that we understand its reproductive ecology. Floral morphology was described based on field and scanning electron microscopic examination. The reproductive system was determined through experimentally controlled pollination along with observations of pollen tube growth. Pollinators were identified through field observations. Flowers of O. porosa are small, shallow, inconspicuous, asynchronous and grouped in inflorescences. This species presented self-compatibility, but did not reproduce through apomixy and spontaneous selfpollination was very rare (5%). Despite being monoclinal, flowers were protogynic, and the gynoecium was receptive after the first day of anthesis when the anthers were closed. Spontaneous self-pollination was avoided by the extrorse position of the anthers of the internal stamens. Frankliniella gardeniae (Thysanoptera) was the only pollinating species observed and, after visiting several asynchronous flowers in the same inflorescence, favors geitonogamy. Together the small distance supposedly achieved by thrips in flight and the small population density of O. porosa can reduce the chances of cross-pollination in this species. If so, conservation measures must include preservation of the current population and possibly planting to increase population density. This would reduce the distance between individuals and increase genetic variability. Thrips as pollinators must be included in conservation planning for O. porosa.

Arbuscular mycorrhizal fungi (AMF) associations benefit host plants due to increased ability to obtain resources and hence may influence competitive interactions. Here we experimentally examine growth in Cabralea canjerana and Lafoensia pacari at different densities and with and without AMF. In the density treatment pots had either six or 12 individuals. Half of each treatment was innoculated with AMF and the other half was not. The proportion of each species in each pot was also varied. The AMF did not apparently influence interspecific competitive interactions because growth was similar in both treatments. However, intra-specific competition was very strong in C. canjerana while more moderate in L. pacari and both were influenced by the presence of the AMF. The AMF-Cabralea canjerana interaction was parasitic, while AMF-L. pacari interactions were mutualistic. Thus, dependence upon AMF and intraspecific interactions that result as a consequence of that dependence varies among species and may be an important influence in community structure.

Para o desenvolvimento sustentável é necessária ampla base de informações da biodiversidade e processos ecológicos para avaliar os benefícios das atividades humanas e seus custos ambientais. Criada em 1975, a Reserva Ecológica do IBGE é um centro de referência na produção de informações sobre o Cerrado, conciliando a conservação, pesquisa de ambientes preservados e experimentos sobre impactos com projetos de longa duração desenvolvidos em conjunto com parceiros de diversas instituições. Paralelamente, seu programa de pesquisas emprega amostragem ao longo do Cerrado avaliando padrões e descrevendo a biodiversidade regional. Para atender às novas demandas, a Reserva tem voltado seu manejo para novos objetivos de conservação, articulado a participação em redes de pesquisa e preparado ações de ensino e extensão.