Accelerated body size evolution in upland environments is correlated with recent speciation in South American freshwater fishes.

Speciation rates vary greatly among taxa and regions and are shaped by both biotic and abiotic factors. However, the relative importance and interactions of these factors are not well understood. Here we investigate the potential drivers of speciation rates in South American freshwater fishes, the most diverse continental vertebrate fauna, by examining the roles of multiple biotic and abiotic factors.

Effect of Productivity on Community Size Explains the Latitudinal Diversity Gradient of South American Small Mammals.

AbstractAlthough many studies have shown that species richness increases from high to low latitudes (the latitudinal diversity gradient), the mechanisms responsible for generating and maintaining higher species richness in the tropics remain intensely debated. Here we investigate how the effects of temperature on speciation rates (kinetic effects) and the effects of productivity on community size (chemical effects) explain the latitudinal diversity gradient of South American small mammals. We implemented Bayesian models that integrate processes from the neutral and metabolic theories, comparing model predictions with empirical richness patterns.

The scale-dependent effect of environmental filters on species turnover and nestedness in an estuarine benthic community.

Environmental filtering is a major mechanism structuring ecological communities. However, it is still not clear how different abiotic drivers composing the environmental filter interact with each other to determine local species assemblage and create spatial patterns in species distribution. Here, we evaluated the effects of two strong and uncorrelated environmental variables (salinity and sediment properties) on the β-diversity of an estuarine macrobenthic community while accounting for spatial effects.

Description of the imago of (Isoptera: Termitidae: Termitinae).

The neotropical termite genus Neocapritermes Holmgren (1912) was revised by Krishna & Araujo (1968), who recognized 14 valid species. Two additional species were described by Constantino (1991), and another one by Bandeira & Cancello (1992). However, the imago of most species of Neocapritermes remain unknown.

Prezygotic resource-allocation dynamics and reproductive trade-offs in Calymperaceae (Bryophyta).

Premise Of The Study: Resource allocation is difficult to characterize in plants because of the challenges of quantifying gametes and propagules. We surveyed six sympatric, unisexual species in the family Calymperaceae (Bryophyta) to test for trade-offs in prezygotic sexual and asexual expression and density-dependent survivorship of female gametangia.

Methods: We tallied gametangial and asexual propagule output for 1820 shoots from 17 populations of six species at monthly intervals during one year (2010-2011) in a central Amazonian forest.