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Browsing Staff publications (ES) by Subject "3103 Ecology"

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    Evaluating the potential of oxygen isoscapes for tropical timber tracing
    (Elsevier, 2025-08-15) Vlam, Mart; Boeschoten, Laura; van der Sleen, Peter; Adzkia, Ulfa; Boom, Arnoud; Bouka, Gaël U. D.; Ciliane-Madikou, Jannici C. U.; Kuzee, Tijs; Obiang, Nestor Laurier Engone; Guieshon-Engongoro, Mesly; Loumeto, Joël J.; Mbika, Dieu-merci M. F.; Moundounga, Cynel G.; Ndangani, Rita M. D.; Bourobou, Dyana Ndiade; Paredes-Villanueva, Kathelyn; Rahman, Mohamad M.; Meyer-Sand, Barbara Rocha Venâncio; Siregar, Iskandar Z.; Tassiamba, Steve N.; Tchamba, Martin T.; Toumba-Paka, Bijoux B. L.; Zanguim, Herman T.; Zemtsa, Pascaline T.; Zuidema, Pieter A.
    Independent verification of timber origin is needed to enforce legislation aimed at combatting illegal tropical timber trade. A potential technique is tracing back the stable isotope signal preserved in wood samples, but the scarcity of reference data currently hampers its operationalization. This can be overcome by creating isoscapes. Here we develop continental isoscapes (at 0.5° resolution) for five tropical timbers based on wood δ18O ratios and assess their potential for timber tracing. We compiled a pantropical database of δ18O measurements from 712 trees in 20 countries. We tested effects of δ18O in rainfall, potential evapotranspiration (PET), temperature and precipitation on wood δ18O and used these to develop isoscapes based on quantile regression forests. A first indication of the tracing potential of these isoscapes was tested in leave one out cross validation (LOOCV) analyses. Across the five isoscapes, ranges in wood δ18O values (10th-90th percentile) averaged 3.9 ‰ and δ18O differences increased with distance. Yet local variability in wood δ18O was substantial compared to large-scale variability. The LOOCV analysis showed that the actual origin was included in the probable origin for 59–79 % of the cases. The area of probable origin was large, however, suggesting a low spatial precision of assignment. This study finds limited support for a potential to use wood oxygen isoscapes for tropical timber tracing within continents. Necessary future steps in timber isotope tracing include improving regional representation, conducting similar analyses for other isotopes, rigorous testing of species differences and conducting blind sample tests.
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    Rivers as natural capital assets: a quick scoping review to assess the evidence linking river asset condition to changes in the flow of ecosystem services
    (Wiley, 2025) Zini, Valentina; Johnson, Natalie; Crouch, Alice; Lenagan, Gerard; Cooper, Chris; Naura, Marc; Speck, Imogen; Rouquette, Jim
    River managers are beginning to adopt natural capital approaches in practice. However, while it is crucial for river management, the link between river asset condition and the flow of ecosystem services is poorly understood. In this study, we conducted a Quick Scoping Review (QSR) of the research into river asset condition and ecosystem service delivery to explore the current state of knowledge. The review team developed a PICO (Population, Intervention, Control, Outcome) model to transpose the concepts of the research enquiry into a search strategy for the evidence base and used a Delphi screening exercise to prioritise a subset of literature for the narrative findings. VOSviewer was used to analyse the high‐level linguistic themes from the full list of references. This co‐designed, collaborative and objective QSR approach allowed us to examine a large body of literature in a reproducible manner while minimising bias, demonstrating best practice for evidence review that should be continuously updated, generating a ‘living evidence’ knowledge asset. The results of the review demonstrate there is some knowledge of the mechanisms linking the condition of river assets to the delivery of ecosystem services for the majority of the broad range of ecosystem services analysed, with the exception of some of the cultural services, where comparatively fewer studies explore this link. However, a clear understanding of the quantitative evidence of the relationships between condition and ecosystem service delivery is missing for all of the ecosystem services. This gap stems from a lack of standardised methodologies used across the studies and a focus on a narrow range of definitions of condition. The gap needs to be addressed in future research on the topic, and a first step is to adopt more standardised indicators of river asset condition.
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    Solidago canadensis modifies microbial community and soil physicochemical properties through litter leachates and root exudates
    (Oxford University Press (OUP), 2025-04) Bo, Yanwen; Liao, Yali; Pawlett, Mark; Akbar, Rasheed; Girkin, Nickolas T.; Sun, Jianfan; Ali, Amjad; Ahmad, Naushad; Liu, Wei; Wang, Xiaoyan; Du, Daolin
    Invasive plant inputs alter soil microbial communities via chemical compounds in litter, root exudates, and leachate, impacting a range of soil processes, but precise effects are poorly understood. We examined Solidago canadensis, a common invasive species in China, and its litter effects on soil microbial communities under natural conditions. Experimental treatments included S. canadensis seedling density (1 and 2 plants/pot) and quantity of litter (10 and 20 g/pot), with control groups that contained no plants or litter. After 120 days, soil samples were analyzed for physico-chemical properties, GC-MS chemical composition, and bacterial community composition using high-throughput sequencing. Results showed that S. canadensis seedlings and litter inputs increased soil pH, organic matter (SOM), and nitrogen (TN), while phosphorus and potassium remained unchanged. We identified 66 chemical compounds, predominantly ketones, alcohol, aldehyde, hydrocarbon, ester, acid, terpenoids, and alkaloids, associated with the presence of the invasive species, alongside shifts in dominant bacterial genera including Sphingomonas, Acidobacteriales, and Gemmatimonas. Rarer genera under the invasive treatment species, such as Candidatus, Rhodoplanes and Novosphingobium, correlated positively with soil TN, pH, and SOM. Collectively, our results demonstrate how the increased presence of allelochemicals from S. canadensis litter significantly impact soil properties and bacterial communities, and may therefore have implications for ecosystem dynamics.