Experimental Study on Potential Influence of the Invasive Hedychium coronarium J. König on the Evapotranspiration of Riparian Plant Community.

The balance between precipitation and evapotranspiration (ET) has direct effect on vegetation, and any change in its structure and composition can influence it. The aim of this study is to determine experimentally the daily evapotranspiration (ET) of the invasive species, Hedychium coronarium, and to compare with a group of four native species of the riparian forest. The experiment was carried out in a greenhouse with three different treatments: (1) only the invasive species; (2) only native species; and (3) a mixture of invasive and native species. In each lysimeter, pressure transducers recorded the water level at every 15 min along 14 months. Daily ET was calculated by the method of Gribovszki et al. (2008) and varied according to the treatment, indicating that different species (invasive or native) use the water differently. The maximum accumulated daily ET occurred for mixture treatment (2540.16 mm), while the treatment with the invasive plant presented the lowest value (2172.53 mm). H. coronarium, in monodominant stands, can reduce evapotranspiration on invaded areas and increase it when immersed in the riparian forest.

Rediscovery of presumably extinct species of Aristida in São Paulo State, Brazil / Redescoberta de espécies presumivelmente extintas de Aristida no estado de São Paulo, Brasil

Abstract Two species of Poaceae (Aristidoideae) Aristida ekmaniana Henrard and A. macrophylla Hack. considered "presumably extinct" in the Brazilian state of São Paulo were rediscovered during fieldwork. We hereby describe the location, ecosystem, and habitat type where the species were found. We suggest these grasses be removed from the list of extinct species and be placed in a category compatible with the current knowledge about their conservation status in the state of São Paulo.

Resumo Duas espécies de Poaceae (Aristidoideae), Aristida ekmaniana Henrard e A. macrophylla Hack., consideradas "presumivelmente extintas" no estado de São Paulo, Brasil, foram redescobertas durante trabalho em campo. Descrição, ilustração e observações ecológicas são apresentadas, incluindo locais de observação, ecossistemas e habitats. Sugerimos a revisão do status de conservação das espécies no estado de São Paulo.

Effect of hydrophysical properties on pipe formation in tropical soils.

Piping is an erosive process in which subsurface soil particles are removed, causing the formation of underground tunnels. A variety of physical and chemical factors control pipe formation. This study focused on hydrophysical soil properties to propose a mechanism to explain the piping process in soils in a tropical climate in Brazil. We observed two levels of pipes in the field: shallow pipes that form at the transition between E/B horizons (~0.30-0.45 m) and deep pipes that form between different Bt horizons (~1.50 m). We collected disturbed soil samples to determine the soil particle distribution and organic matter content, and undisturbed soil samples were collected to determine the hydrophysical attributes and for soil micromorphometric analysis. We found that the study area was prone to soil collapse and that physical properties controlled the process. The results showed a textural and structural gradient between the E and Bt horizons, where the Bt horizons presented a higher clay content and a well-developed structure (strong sub-angular blocks) compared to the essentially sandy E horizons (single grain). This gradient changed the soil porosity from macroporosity in the E horizon to microporosity in the Bt horizon, particularly represented by the decrease in complex pores. For deeper pipes, soil attribute gradients were found between different Bt horizons. A modification in the structure grade from moderate to weakly moderate, soil water retention curves with different slopes and shapes, and an increase in porosity correlating with soil depth, reflect an increase in larger complex pores. These changes in structure, texture, porosity, and pore type reflect the soil's hydraulic conductivity in the transition of different horizons, which can promote the accumulation and temporary stagnation of water at the top of the Bt horizons, and trigger the piping process when the lateral water flow reaches the critical flow velocity.

Four challenges when conducting bibliometric reviews and how to deal with them.

The evidence base in environmental sciences is increasing steadily. Environmental researchers have been challenged to handle massive volumes of data to support more comprehensive studies, assess the current status of science, and move research towards future progress. Bibliometrics can provide important insights into the research directions by providing summarized information for several end users. Here, we present an in-depth discussion on the use of bibliometric indicators to evaluate research outputs through four case studies comprising disciplines in environmental sciences. We discuss four big challenges researchers may face when conducting bibliometric reviews and how to deal with them. We also address some primary questions researchers may answer with bibliometric mapping, drawing lessons from the case studies. Lastly, we clarify some misuses of review concepts and suggest methodological principles of systematic reviews and maps to improve the overall quality of bibliometric studies.