Tomelleri, E. | bioRxiv Science

bioRxiv2024

Enhancing timber traceability via multielement and strontium isotope ratio: An example from the Eastern Alps

International timber trading is subject to rigorous certification schemes that require the disclosure of essential information, including the tree species and geographic origin of the timber in question. Regrettably, the lack of readily accessible forensic tools to verify compliance has facilitated the proliferation of illegal timber trading, with dramatic consequences for ecosystems and biodiversity. The objective of this study was to investigate the potential of a multichemical approach based on the multielement and strontium isotope (87Sr/86Sr) ratio analysis combined with chemometrics to test sample recognition according to their species and geographic origin. The sampling area covered a portion of the Eastern Alpine region, which is characterised by a significant economic reliance on wood. The study focused on three representative species from local forests: Norway spruce, European larch, and Swiss stone pine. Samples were characterised from stands grown on diverse bedrock types. Our findings revealed a strikingly consistent variation in the multielement profiles across different species, thereby enabling flawless sample recognition. Considering the geographic origin, the 87Sr/86Sr ratio proved to be a pivotal parameter, by virtue of its correlation with the geo-lithological composition of the growing area. Combining the chemical markers, an accurate sample classification based on multiple decision trees was attained, even comparing forest stands grown on the same bedrock type. These findings offer novel insights into the utilisation of chemical markers in provenancing and authenticity studies, thereby enhancing the adoption of integrated approaches to counteract illegal timber trade.

ecology↗

bioRxiv2023

A novel method for characterising the inter- and intra-lake variability of CH4 emissions: validation and application across a latitudinal transect in the Alpine region

Lakes in the Alpine region are recognised as critical CH4 emitters, but a robust characterisation of the magnitude and variability of CH4 fluxes is still needed. We developed a mobile platform for CH4 eddy covariance (EC) flux measurements to tackle this gap. Our approach was shown to be well suited to catch all CH4 emission pathways and overcome the limitations of other methods (e.g., gradient-based). This is by surpassing their local nature and thus being suited for characterising the variability of the within-lake emissions, primarily because of CH4 emissions by ebullition stochasticity. The mobile system was deployed at nine lakes across a latitudinal transect in the Alps and validated by comparing the measured fluxes with a fixed EC station and to chambers and boundary layer estimates. Methane fluxes were explained by water turbidity, dissolved organic carbon, dissolved nitrogen, elevation, particulate organic carbon, and total phosphorus. The highest fluxes and most substantial seasonal variability were found in a shallow low-altitude lake in the Southern Alps. Additionally, the mobile EC permitted to resolve the spatial structure of fluxes at the selected lakes. Finally, we demonstrated the usability of our novel mobile system to characterise intra- and inter-lake variability of fluxes. We suggest that characterising the intra-lake emission heterogeneity and a deeper understanding of inter-lake emission magnitude differences is fundamental for a solid estimate of freshwater CH4 budgets. Key PointsO_LICH4 emissions from alpine lakes are recognised to be an important component to the global methane budget but they are poorly characterized C_LIO_LIWe developed and validated a mobile eddy covariance platform for capturing CH4 fluxes across lakes in the alpine region for two years C_LIO_LIA robust statistical model based on a few in-situ physicochemical and biological parameters can be generally used to predict CH4 fluxes C_LI

ecology↗