Winner-loser plant trait replacements in human-modified tropical forests.

Anthropogenic landscape modification may lead to the proliferation of a few species and the loss of many. Here we investigate mechanisms and functional consequences of this winner-loser replacement in six human-modified Amazonian and Atlantic Forest regions in Brazil using a causal inference framework. Combining floristic and functional trait data for 1,207 tree species across 271 forest plots, we find that forest loss consistently caused an increased dominance of low-density woods and small seeds dispersed by endozoochory (winner traits) and the loss of distinctive traits, such as extremely dense woods and large seeds dispersed by synzoochory (loser traits).

Pervasive gaps in Amazonian ecological research.

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases.

Anthropogenic disturbance in tropical forests can double biodiversity loss from deforestation.

Concerted political attention has focused on reducing deforestation, and this remains the cornerstone of most biodiversity conservation strategies. However, maintaining forest cover may not reduce anthropogenic forest disturbances, which are rarely considered in conservation programmes. These disturbances occur both within forests, including selective logging and wildfires, and at the landscape level, through edge, area and isolation effects.

Effects of preparation conditions of poly(lactide-co-glycolide) nanoparticles loaded with amphiphilic porphyrins and their photoactivities.

Three porphyrins, (5,10,15,20-tetra(3-hydroxyphenyl)porphyrin, 5-hexyl-10,20-bis(3-hydroxyphenyl)-porphyrin and 5-hexyl-10,15,20-tris(3-hydroxyphenyl)porphyrin), with different amphiphilicities and equal singlet oxygen quantum yields in ethanol, were encapsulated into 50:50 poly(lactide-co-glycolide), nanoparticles prepared by the emulsion/evaporation technique. A 22 factorial design was utilized to evaluate the influence of the porphyrin/polymer mass ratio and the percentage of ethanol in the aqueous phase on the size and zeta potential of the nanoparticles. Increasing both the amount of ethanol and the porphyrin/polymer ratio decreases the size and increases zeta potential for the photosensitizers studied, except for 5-hexyl-10,15,20-tri(3-hydroxyphenyl)porphyrin.

Wildfires in bamboo-dominated Amazonian forest: impacts on above-ground biomass and biodiversity.

Fire has become an increasingly important disturbance event in south-western Amazonia. We conducted the first assessment of the ecological impacts of these wildfires in 2008, sampling forest structure and biodiversity along twelve 500 m transects in the Chico Mendes Extractive Reserve, Acre, Brazil. Six transects were placed in unburned forests and six were in forests that burned during a series of forest fires that occurred from August to October 2005.

Quantifying responses of dung beetles to fire disturbance in tropical forests: the importance of trapping method and seasonality.

Understanding how biodiversity responds to environmental changes is essential to provide the evidence-base that underpins conservation initiatives. The present study provides a standardized comparison between unbaited flight intercept traps (FIT) and baited pitfall traps (BPT) for sampling dung beetles. We examine the effectiveness of the two to assess fire disturbance effects and how trap performance is affected by seasonality.

Factors affecting the abundance of leaf-litter arthropods in unburned and thrice-burned seasonally-dry Amazonian forests.

Fire is frequently used as a land management tool for cattle ranching and annual crops in the Amazon. However, these maintenance fires often escape into surrounding forests, with potentially severe impacts for forest biodiversity. We examined the effect of experimental fires on leaf-litter arthropod abundance in a seasonally-dry forest in the Brazilian Amazon.