Competition, resources, and vegetation during 10 years in native grassland

Looking for Hidden Enemies of Metabarcoding: Species Composition, Habitat and Management Can Strongly Influence DNA Extraction while Examining Grassland Communities

Despite the raising preoccupation, the critical question of how the plant community is composed belowground still remains unresolved, particularly for the conservation priority types of vegetation. The usefulness of metabarcoding analysis of the belowground parts of the plant community is subjected to a considerable bias, that often impedes detection of all species in a sample due to insufficient DNA quality or quantity. In the presented study we have attempted to find environmental factors that determine the amount and quality of DNA extracted from total plant tissue from above- and belowground samples (1000 and 10,000 cm2). We analyzed the influence of land use intensity, soil properties, species composition, and season on DNA extraction. The most important factors for DNA quality were vegetation type, soil conductometry (EC), and soil pH for the belowground samples. The species that significantly decreased the DNA quality were Calamagrostis epigejos, Coronilla varia, and Holcus lanatus. For the aboveground part of the vegetation, the season, management intensity, and certain species-with the most prominent being Centaurea rhenana and Cirsium canum-have the highest influence. Additionally, we found that sample size, soil granulation, MgO, organic C, K2O, and total soil N content are important for DNA extraction effectiveness. Both low EC and pH reduce significantly the yield and quality of DNA. Identifying the potential inhibitors of DNA isolation and predicting difficulties of sampling the vegetation plots for metabarcoding analysis will help to optimize the universal, low-cost multi-stage DNA extraction procedure in molecular ecology studies.

Species richness of arbuscular mycorrhizal fungi: associations with grassland plant richness and biomass

Although experiments show a positive association between vascular plant and arbuscular mycorrhizal fungal (AMF) species richness, evidence from natural ecosystems is scarce. Furthermore, there is little knowledge about how AMF richness varies with belowground plant richness and biomass. We examined relationships among AMF richness, above- and belowground plant richness, and plant root and shoot biomass in a native North American grassland. Root-colonizing AMF richness and belowground plant richness were detected from the same bulk root samples by 454-sequencing of the AMF SSU rRNA and plant trnL genes. In total we detected 63 AMF taxa. Plant richness was 1.5 times greater belowground than aboveground. AMF richness was significantly positively correlated with plant species richness, and more strongly with below- than aboveground plant richness. Belowground plant richness was positively correlated with belowground plant biomass and total plant biomass, whereas aboveground plant richness was positively correlated only with belowground plant biomass. By contrast, AMF richness was negatively correlated with belowground and total plant biomass. Our results indicate that AMF richness and plant belowground richness are more strongly related with each other and with plant community biomass than with the plant aboveground richness measures that have been almost exclusively considered to date.

A mechanism aiding simultaneously reciprocal mating in snails

The majority of hermaphroditic animals mate on a given occasion as either male or female, but terrestrial snails and slugs generally mate reciprocally with each partner participating in both sexual roles. This manner of mating requires that the genitalia be exactly opposed prior to copulation attempts, a task made difficult in snails and slugs by the absence of hearing and very limited vision. In the brown garden snail, Cornu aspersum (Müller, 1774), we found that a small protruding structure associated with the genital atrium plays an important role in positioning the snails prior to copulation. Lesions of the penial lobe reduced mating success rates, delayed mating, increased the number of attempted intromissions, and increased the number of unilateral intromissions. The sensory capacity of the penial lobe is demonstrated by histological and electrophysiological evidence, and behavioral data suggest that the lobe is also a stimulus for the partner snail. A literature review suggests that structures functionally equivalent to the penial lobe may be present in many gastropod molluscs that mate simultaneously and reciprocally, but in none that mate in other ways.