Global distribution of earthworm diversity

Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide.

Dragonflies and damselflies (Odonata) from Córdoba and San Luis provinces, Argentina

Nineteen geographical records for species of Odonata in 2 provinces of Argentina are documented. We provided records for 9 newly recorded species for Córdoba: Lestes spatula Fraser, 1946, Andinagrion peterseni (Ris, 1908), Argentagrion ambiguum (Ris, 1904), Erythemis attala (Selys in Sagra, 1857), Erythemis plebeja (Burmeister, 1839), Erythrodiplax media Borror, 1942, Micrathyria longifasciata Calvert, 1909, Micrathyria hypodidyma Calvert, 1906, and Tramea cophysa Hagen, 1867. In San Luis, we provided records for 10 newly recorded species: Hetaerina rosea Selys, 1853, Acanthagrion lancea Selys, 1876, Ischnura fluviatilis Selys, 1876, Oxyagrion rubidium (Rambur, 1842), Castoraeschna decurvata Dunkle & Cook, 1984, Rhionaeschna pallipes (Fraser, 1947), Phyllocycla argentina (Hagen in Selys, 1878), Erythrodiplax corallina (Brauer, 1865), Perithemis mooma Kirby, 1889, and Planiplax erythropyga (Karsch, 1891). Among these records, we extend the geographic distribution of A. peterseni and R. pallipes, which are endemic to Argentina and recorded P. erythropyga for the first time in Chaco phytogeographic province.

Bacterial indicator of agricultural management for soil under no-till crop production

The rise in the world demand for food poses a challenge to our ability to sustain soil fertility and sustainability. The increasing use of no-till agriculture, adopted in many areas of the world as an alternative to conventional farming, may contribute to reduce the erosion of soils and the increase in the soil carbon pool. However, the advantages of no-till agriculture are jeopardized when its use is linked to the expansion of crop monoculture. The aim of this study was to survey bacterial communities to find indicators of soil quality related to contrasting agriculture management in soils under no-till farming. Four sites in production agriculture, with different soil properties, situated across a west-east transect in the most productive region in the Argentinean pampas, were taken as the basis for replication. Working definitions of Good no-till Agricultural Practices (GAP) and Poor no-till Agricultural Practices (PAP) were adopted for two distinct scenarios in terms of crop rotation, fertilization, agrochemicals use and pest control. Non-cultivated soils nearby the agricultural sites were taken as additional control treatments. Tag-encoded pyrosequencing was used to deeply sample the 16S rRNA gene from bacteria residing in soils corresponding to the three treatments at the four locations. Although bacterial communities as a whole appeared to be structured chiefly by a marked biogeographic provincialism, the distribution of a few taxa was shaped as well by environmental conditions related to agricultural management practices. A statistically supported approach was used to define candidates for management-indicator organisms, subsequently validated using quantitative PCR. We suggest that the ratio between the normalized abundance of a selected group of bacteria within the GP1 group of the phylum Acidobacteria and the genus Rubellimicrobium of the Alphaproteobacteria may serve as a potential management-indicator to discriminate between sustainable vs. non-sustainable agricultural practices in the Pampa region.