Vegetation maps based on remote sensing are informative predictors of habitat selection of grassland birds across a wetness gradient

Vegetation is a major environmental factor influencing habitat selection in bird species. High resolution mapping of vegetation cover is essential to model the distribution of populations and improve the management of breeding habitats. However, the task is challenging for grassland birds because microhabitat variations relevant at the territory scale cannot be measured continuously over large areas to delineate areas of higher suitability. Remote sensing may help to circumvent this problem. We addressed this issue by using SPOT 5 imagery and phytosociological data. We mapped grassland vegetation in a floodplain using two methods. We (i) mapped the continuous Ellenberg index of moisture and (ii) identified 5 vegetation classes distributed across the wetness gradient. These two methods produced consistent output maps, but they also provided complementary results. Ellenberg index is a valuable proxy for soil moisture while the class approach provided more information about vegetation structure, and possibly trophic resources. In spite of the apparent uniformity of meadows, our data show that birds do not settle randomly along the moisture and vegetation gradients. Overall birds tend to avoid the driest vegetation classes, i.e. the highest grounds. Thus, vegetation maps based on remote sensing could be valuable tools to study habitat selection and niche partition in grassland bird communities. It is also a valuable tool for conservation and habitat management.     

Plant functional types and climatic change: Introduction

Abstract. Plant functional types are a necessary device for reducing the complex and often uncharted characteristics of species diversity in function and structure when attempting to project the nature and function of species assemblages into future environments. A workshop was held to review the current methods commonly used for defining plant functional types, either globally or for particular biomes, and to compare them with the field experiences of specialists for specific biomes of the world. The methods fall into either an objective and inductive approach or a subjective and deductive approach. When the different methods were tested, it was generally found that the classification for one site or environment was not wholly applicable to a different site or environment. However, the degree of change which is necessary for adjustment between environments may not prove to be a major limitation in the use of functional types.     

Comparative HILIC/ESI-QTOF-MS and HPTLC studies of pyrrolizidine alkaloids in flowers of Tussilago farfara and roots of Arnebia euchroma

The utility of HPTLC and HILIC/ESI-QTOF-MS for the determination of pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs) was compared in the selected plant species: Tussilago farfara L. (TF, flower) and Arnebia euchroma (Royle) I.M. Johnst. (AE, root). HPTLC confirmed the postulated presence of PAs (saturated and unsaturated) or PANOs in the tested extracts. In accordance with previous studies, HILIC/ESI-Q-TOF-MS confirmed the presence of the toxic PA senkirkine and the saturated otonecine-type PAs, tussilagine and isotussilagine in the TF extract and 7-angeloylretronecine and 9-angeloylretronecine in AE extract. Moreover, the following alkaloids were identified in AE root: intermedine, intermedine-N-oxide, leptanthine-N-oxide, echimidine-N-oxide (or their corresponding stereoisomers) and traces of 7-angeloylretronecine and 9-angeloylretronecine-N-oxide. The study demonstrates the HILIC/ESI-Q-TOF-MS method to be a very useful tool for monitoring PAs and PANOs in the test samples, even when not all of the necessary standards are available. Quantitative analysis of senkirkine in TF flower by HILIC/ESI-QTOF-MS featured high resolution, high precision, high mass accuracy, and very high sensitivity with limit-of-detection (LOD) of 27.50 fg/μL and limit-of-quantitation (LOQ) of 91.60 fg/μL. The results from both methods may be used for the development or rejection of European Pharmacopoeia (X) monographs of both investigated species.     

Accuracies in Po-210 determination for lead-210 dating

Various laboratory techniques have been utilized worldwide for measuring lead-210 in sub-recent deposits through its grand-daughter product polonium-210. Isotope dilution alpha spectrometry proved a suitable tool for absolute determination of lead-210 for the dating of aquatic deposits. Moreover, isotope dilution alpha spectrometry along with speciation experiments can be used to resolve depositional anomalies arising from supported lead-210/Ra-226 disequilibrium levels and unsupported lead-210 mobile fractions. Isotope dilution alpha spectrometry of sub-recent sediment and peat deposits has been critically evaluated for more than ten years. Our results show that type, size and composition of deposits analyzed as well as radiochemical procedures used, together with alpha counting techniques, are important factors influencing lead-210 determinations and tailing corrections using its granddaughter product polonium-210. Optimization of these parameters is of prime importance to achieve economic and accurate analyses, especially at low lead-210 concentrations and small sample sizes.     

Latitudinal comparison of altitudinal changes in forest structure,leaf-type,and species richness in humid monsoon Asia

A new template for mountain vegetation zonation along latitudinal gradients is proposed for examining geographical pattern of various forest attributes in humid monsoon Asia. The contrasting temperature regime in tropical and temperate mountains, i.e., the former is a non-seasonal, temperature-sum controlled environment, and the latter is a seasonal, low temperature limiting environment, leads to different altitudinal patterns of tree height distribution and species richness. In the tropical mountains, both tree height and species richness decrease steeply, and the tree height often stepwise. The decline of tree height and species diversity in the temperate mountains is far less pronounced except near the forest limit. Both trends are explained by their temperature regime.     

Humulus lupulus L. cv. Cascade grown in Northern Italy: morphological and phytochemical characterization

Abstract

Several aroma hops (Humulus lupulus L.) were recently introduced in Northern Italy as a small-scale production of excellence. In this preliminary study, the American cultivar Cascade was investigated in a combined morphological and phytochemical survey. Morphological investigation on trichome structure, density and distribution was performed by scanning electron microscopy and light microscopy. Essential oil composition, α/β-acid and polyphenol profiles over 3 years were determined by GC-MS and HPLC analyses. Two types of non-glandular (simple and cystolithic) and glandular (peltate and bulbous) trichomes were observed on leaves and female inflorescences. The peltate trichomes resulted as the main sites of terpene production and accumulation. The essential oil profiles showed myrcene, β-caryophyllene, (E)-β-farnesene and humulene epoxide II as the dominant compounds over the three collection times, although with different relative abundances. The presence of two exclusive compounds, γ-muurolene and trans-γ-cadinene, characterized the investigated cv. Cascade, potentially enhancing herbal, woody and spicy aroma traits of this cultivation in Northern Italy. The bitter acid composition showed quantitative values consistent with literature data only for the second and third monitoring year. Qualitative differences in polyphenol content were also recorded, for the presence of quercetin-3-O-malonylglucoside and kaempferol-3-O-rutinoside, which may characterize this peculiar Italian cultivation.     

To share or not to share: Incentivizing data sharing in life science communities

Most scientists recognize the importance of sharing data online in an open fashion. Nonetheless, many studies have documented the concerns that accompany data sharing activities, including loss of credit or IP, misuse and the time needed to curate interoperable data. To this end, discussions around data sharing often identify incentives that could potentially ameliorate these disincentivising concerns. Nonetheless, current Open Data discussions often rely on evidence‐based studies to identify the disincentives to overcome. This results in highly specific and directed interventions. In contrast, this paper offers a different interpretation of these concerns. To do so, it makes use of the Thomas Theorem which suggests that: “If men define situations as real, they are real in their consequences”. Using empirical evidence from sub‐Saharan African (bio)chemistry laboratories, this paper illustrates how individual perceptions of research environments – whether associated with evidence or not – are highly influential in shaping data sharing practices. It concludes with the suggestion that discussion on incentivising data sharing amongst scientific communities need to take a broader set of concerns into account and offer a more creative approach to ameliorating environmental disincentives.     

Adipose triglyceride lipase regulates eicosanoid production in activated human mast cells

Human mast cells (MCs) contain TG-rich cytoplasmic lipid droplets (LDs) with high arachidonic acid (AA) content. Here, we investigated the functional role of adipose TG lipase (ATGL) in TG hydrolysis and the ensuing release of AA as substrate for eicosanoid generation by activated human primary MCs in culture. Silencing of ATGL in MCs by siRNAs induced the accumulation of neutral lipids in LDs. IgE-dependent activation of MCs triggered the secretion of the two major eicosanoids, prostaglandin D2 (PGD2) and leukotriene C4 (LTC4). The immediate release of PGD2 from the activated MCs was solely dependent on cyclooxygenase (COX) 1, while during the delayed phase of lipid mediator production, the inducible COX-2 also contributed to its release. Importantly, when ATGL-silenced MCs were activated, the secretion of both PGD2 and LTC4 was significantly reduced. Interestingly, the inhibitory effect on the release of LTC4 was even more pronounced in ATGL-silenced MCs than in cytosolic phospholipase A₂-silenced MCs. These data show that ATGL hydrolyzes AA-containing TGs present in human MC LDs and define ATGL as a novel regulator of the substrate availability of AA for eicosanoid generation upon MC activation.