Ecological and evolutionary consequences of living in a defaunated world

Defaunation, the loss or population decline of medium and large native vertebrates represents a significant threat to the biodiversity of tropical ecosystems. Here we review the anthropogenic drivers of defaunation, provide a brief historical account of the development of this field, and analyze the types of biological consequences of this impact on the structure and functioning of tropical ecosystems. We identify how defaunation, operating at a variety of scales, from the plot to the global level, affects biological systems along a gradient of processes ranging from plant physiology (vegetative and reproductive performance) and animal behavior (movement, foraging and dietary patterns) in the immediate term; to plant population and community dynamics and structure leading to disruptions of ecosystem functioning (and thus degrading environmental services) in the short to medium term; to evolutionary changes (phenotypic changes and population genetic structure) in the long-term. We present such a synthesis as a preamble to a series of papers that provide a compilation of our current understanding of the impact and consequences of tropical defaunation. We close by identifying some of the most urgent needs and perspectives that warrant further study to improve our understanding of this field, as we confront the challenges of living in a defaunated world. © 2013 Elsevier Ltd.

Perspectives on the use of lakes and ponds as model systems for macroecological research

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Food web structure in a tropical stream ecosystem

This study investigated the structure and properties of a tropical stream food web in a small spatial scale, characterizing its planktonic, epiphytic and benthic compartments. The study was carried out in the Potreirinho Creek, a second-order stream located in the south-east of Brazil. Some attributes of the three subwebs and of the conglomerate food web, composed by the trophic links of the three compartments plus the fish species, were determined. Among compartments, the food webs showed considerable variation in structure. The epiphytic food web was consistently more complex than the planktonic and benthic webs. The values of number of species, number of links and maximum food chain length were significantly higher in the epiphytic compartment than in the other two. Otherwise, the connectance was significantly lower in epiphyton. The significant differences of most food web parameters were determined by the increase in the number of trophic species, represented mainly by basal and intermediate species. High species richness, detritus-based system and high degree of omnivory characterized the stream food web studied. The aquatic macrophytes probably provide a substratum more stable and structurally complex than the sediment. We suggest that the greater species richness and trophic complexity in the epiphytic subweb might be due to the higher degree of habitat complexity supported by macrophyte substrate. Despite differences observed in the structure of the three subwebs, they are highly connected by trophic interactions, mainly by fishes. The high degree of fish omnivory associated with their movements at different spatial scales suggests that these animals have a significant role in the food web dynamic of Potreirinho Creek. This interface between macrophytes and the interconnections resultant from fish foraging, diluted the compartmentalization of the Potreirinho food web.

Structure and function of the foregut and salivary glands of the synanthropic diplopod Urostreptus atrobrunneus (Spirostreptidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Invasive Africanized honeybees change the structure of native pollination networks in Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Factors determining the structure of fish communities in Pantanal lagoons (MS, Brazil)

The fish communities of lagoons in the Nhecolandia Pantanal were studied to determine the factors which are responsible for the composition and abundance of species. Fishes were collected in 19 lagoons during August 1997, after their isolation from the River Negro, using beach seines (15 x 1.5 m; 2 mm mesh). A total of 51 species were collected. In the lagoons, or in parts with dense macrophytes, a screened box trap was used. Fishing was also accomplished with hooks of several sizes. Species richness was estimated by the jack-knife procedure, after adjustment to the log-normal distribution and with von Bertalanffy's equation (asymptotic). The most important factors in the community organization were macrophyte cover, piscivore abundance and depth of the lagoons. The role of these habitats in the Pantanal ecosystem was discussed.

Food-web composition affects cross-ecosystem interactions and subsidies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relation between green spaces and bird community structure in an urban area in Southeast Brazil

Increased urbanization typically leads to an increase in abundance of a few species and a reduction in bird species richness. Understanding the structure of biotic communities in urban areas will allow us to propose management techniques and to decrease conflicts between wild species and human beings. The objective of this study was to describe the structure of the bird community in an urban ecosystem. The study was carried out in the city of Taubaté in southeastern Brazil. Point-counts were established in areas with different levels of tree density ranging from urban green spaces to predominantly built-up areas. We looked for a correlation between the richness/abundance of birds and the size of the area surveyed, the number of houses, the number of tree species and the number of individual trees. The results of multiple regression showed that bird richness had a direct relationship with vegetation complexity. The abundance and diversity of tree species were better predictors of bird species than the number of houses and size of the area surveyed. We discuss implications of this study for conservation and management of bird diversity in urban areas, such as the need to increase green areas containing a large diversity of native plant species. © 2011 Springer Science+Business Media, LLC.

Floral nectar production and nectary structure of a bee-pollinated shrub from Neotropical savanna

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)