Bruno Bastos Gonçalves

Effects of area and available energy on fish assemblages of tropical streams

A central issue in fish community ecology is to understand how the size of the drainage area and the available energy influence fish species diversity and their spatial distribution. In the present study, we tested whether the species–area relationship (represented by drainage area) and species–energy association (represented by algal biomass and organic matter) drive taxonomic and functional richness in a regional scale. The results indicated that fish assemblages of the two tropical neighbouring basins sampled responded differently to the size of drainage area. Whereas taxonomic richness was influenced by the size of the drainage area in Tocantins River basin streams, it was not affected in Araguaia River basin streams. Both taxonomic richness and functional richness of the fish assemblages were affected by available energy in the system. A possible explanation for these different responses is related to local conditions, such as the percentage of natural vegetation cover encountered in each basin.

Arborização urbana para mitigação das condições microclimáticas em Goiânia, Goiás

Urban trees can influence from landscape factors to microclimatic, affecting human well-being. This study had as objective to characterize two different sectors in Goiânia, Goias, Brazil and to verify how urban trees influence the microclimate. Two different areas, 1 km long each one, in two avenues from the city (Goias Av. and Planicie Av.). In each area, a census from all trees was conducted and the following variables were measured: temperature (oC), relative humidity (%), wind speed (km/h) and light intensity (lux). Descriptive analysis with absolute and relative frequency of tree species, Mann-Whitney (95%) test for comparing abundance among species, T Test (95%) for microclimate variables comparison among full sun and shaded areas in each one of the avenues and the last procedures were a principal components analysis (PCA) and a correspondence analysis (CCA) to verify the influence of environmental variables between full light and shaded areas. In areas shaded by trees crowns, temperatures, light intensity and wind speed showed lower values than shaded areas, while relative humidity showed higher values in these environments than in places without trees. Urban trees contribute to microclimatic conditions improvement in urban landscapes, positively influencing human well-being in urban centers.