Integrating graph-based connectivity metrics into species distribution models

Species distribution models (SDMs) are commonly used in ecology to map the probability of species occurrence on the basis of predictive factors describing the physical environment. We propose an improvement on SDMs by using graph methods to quantify landscape connectivity. After (1) mapping the habitat suitable for a given species, this approach consists in (2) building a landscape graph, (3) computing patch-based connectivity metrics, (4) extrapolating the values of those metrics to any point of space, and (5) integrating those connectivity metrics into a predictive model of presence. For a given species, this method can be used to interpret the significance of the metrics in the models in terms of population structure. The method is illustrated here by the construction of an SDM for the European tree frog in the region of Franche-Comté (France). The results show that the connectivity metrics improve the explanatory power of the SDM and emphasize the important role of the habitat network.     

Degradation of metalaxyl-M in contrasting soils is influenced more by differences in physicochemical characteristics than in microbial community composition after re-inoculation of sterilised soils

Rates of degradation of pesticides by soil microorganisms are believed to depend on both microbial community composition and underlying soil physicochemical characteristics. The aim of this study was to determine which of these factors was more important in determining the rate of degradation of the fungicide metalaxyl-M in two soils. Soils exhibiting highly contrasting metalaxyl-M degradation rates were sterilised by gamma-irradiation and inoculated with either non-sterilised soil from the same site or with the soil from the contrasting site. After re-establishment of microbial communities, soils were treated with metalaxyl-M and the degradation rate (measured by ¹⁴C-HPLC), pH and microbial community structure (multiplex terminal-restriction fragment length polymorphism (T-RFLP) analysis of small subunit rRNA gene sequences) were assessed. Community composition was altered by the sterilisation and re-inoculation strategy but degradation in re-inoculated soils was still most rapid in the soil with the original faster degradation rate. This was the case regardless of the source of the soil inoculum, and the rate of degradation in the soil exhibiting the low natural degradation rate remained low when inoculated with the faster-degrading soil. The results suggest that while the slower-degrading soil possessed a degradative capacity, the degradation rate in this soil was significantly reduced by some of its physicochemical characteristics, despite introduction of the microbial community of the faster-degrading soil. These results and this experimental strategy provide a basis for the assessment of relative importance of the factors limiting biodegradation and management strategies required to enhance degradation rates.     

Gluconic acid,its lactones,and SO(2) binding phenomena in musts from botrytized grapes

Intramolecular gluconic acid esterification reactions led to the formation of two lactones, gamma- and delta-gluconolactone (glucono-1,4-lactone and glucono-1,5-lactone). The presence of the first has not yet been reported in must or wine. These lactones are in equilibrium with gluconic acid, gamma- and delta-gluconolactone representing, respectively, 5.8 and 4.1% of the acid level. Correlations between must SO(2) binding power, gluconic acid, and consequently its lactones are shown. The SO(2) affinity of a mixture containing this acid and gamma- and delta-gluconolactone was determined, and gluconic acid appeared to be indirectly responsible for approximately 8% of the bindable SO(2) in musts from botrytized grapes.     

Presumptive bovine neonatal pancytopenia in a Holstein calf in Québec

An 18-day-old heifer was presented with fever, depression, tachycardia, tachypnea, and prolonged bleeding time. Blood tests revealed severe anemia, thrombocytopenia, and leucopenia. The animal was negative by PCR for bovine virus diarrhea virus antigen. The findings supported a diagnosis of bovine neonatal pancytopenia. Treatments included fresh whole blood transfusion and antibiotics. The animal recovered fully.     

Storage of soil carbon is not sequestration: Straightforward graphical visualization of their basic differences

Over the last few years, in the literature on the incorporation of crop residues in agricultural fields to mitigate climate change, there has been a growing tendency to no longer distinguish between the storage and the sequestration of organic carbon in soils. Applying, apparently for the first time, a simple “back-of-the-envelope” calculation to available mineralization kinetics data, we show graphically that there are fundamental differences, both quantitatively and qualitatively, between the two concepts of storage and sequestration. To avoid confusion, they should therefore never be used interchangeably, especially when addressing farmers and policymakers. Several simplifying assumptions made in the calculations, and about which a considerable lack of understanding persists, mean that at this stage, the graphical visualization we obtained is likely to still be optimistic in terms of the already low (10%) efficacy of sequestering carbon in soils. Several research avenues are outlined to deepen our grasp of the processes involved.     

Expected Response to Selection in Synthetic Populations of Perennial Ryegrass

Confidence intervals for heritability and expected genetic advance of seven agronomic traits in two populations of perennial ryegrass have been computed in two ways (a = bootstrap method; b = parametric method) for five different combinations of selection. Two conclusions can be drawn from our results:

• — Superiority of individual selection over family or every combination of selection.
• — Usefulness of methods based on resampling to estimate confidence intervals for genetic parameters without particular statistical hypotheses.

     

A survey of seasonal temperatures and vineyard altitude influences on 2-methoxy-3-isobutylpyrazine, C13-norisoprenoids, and the sensory profile of Brazilian Cabernet Sauvignon wines

This report has investigated the seasonal temperatures influences (winter and summer) of five vineyards at different altitudes on the concentrations of 2-methoxy-3-isobutylpyrazine (MIBP), alpha- and beta-ionone, and beta-damascenone in 2004 or 2005 vintages of Cabernet Sauvignon wines from Santa Catarina State, Brazil. Sensorial analyses were also carried out on the wine samples and compared to altitude and climate. Significant regression was observed between MIBP concentrations and the vineyard's altitude. No significant relation was observed between alpha- and beta-ionone and beta-damascenone with the vineyard's altitude. Principal component analysis positively correlated wines from higher altitudes with a "bell pepper" aroma. Conversely, the wines made with grapes from lower altitudes were correlated with "red fruits" and "jam" aromas. An important relation between the bell pepper aroma and the lower winter temperature was observed. A strong negative correlation was also observed between seasonal temperatures and vineyard altitude as well as between MIBP content and seasonal temperature of growing grapevines.