Browsing by Author "Quine, Timothy"

Now showing 1 - 6 of 6
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    Bedrock geochemistry influences vegetation growth by regulating the regolith water holding capacity
    (Nature Publishing Group: Nature Communications, 2020-05-13) Jiang, Zihan; Liu, Hongyan; Wang, Hongya; Peng, Jian; Meersmans, Jeroen; Green, Sophie M.; Quine, Timothy; Wu, Xiuchen; Song, Zhaoliang
    Although low vegetation productivity has been observed in karst regions, whether and how bedrock geochemistry contributes to the low karstic vegetation productivity remain unclear. In this study, we address this knowledge gap by exploring the importance of bedrock geochemistry on vegetation productivity based on a critical zone investigation across a typical karst region in Southwest China. We show silicon and calcium concentrations in bedrock are strongly correlated with the regolith water loss rate (RWLR), while RWLR can predict vegetation productivity more effectively than previous models. Furthermore, the analysis based on 12 selected karst regions worldwide further suggest that lithological regulation has the potential to obscure and distort the influence of climate change. Our study implies that bedrock geochemistry could exert effects on vegetation growth in karst regions and highlights that the critical role of bedrock geochemistry for the karst region should not be ignored in the earth system model
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    Ecosystem service delivery in Karst landscapes: anthropogenic perturbation and recovery
    (Springer, 2017-06-09) Quine, Timothy; Guo, Dali; Green, Sophie M.; Tu, Chenglong; Hartley, Iain; Zhang, Xinyu; Dungait, Jennifer; Wen, Xuefa; Song, Zhaoliang; Liu, Hongyan; Buss, Heather; Barrows, Timothy; Evershed, Richard; Johnes, Penny; Meersmans, Jeroen
    Covering extensive parts of China, Karst landscapes are exceptional because rapid and intensive land use change has caused severe ecosystem degradation within only the last 50 years. The twentieth century intensification in food production through agriculture has led to a rapid deterioration of soil quality, evidenced in reduced crop production and rapid loss of soil. In many areas, a tipping point appears to have been passed as basement rock is exposed and ‘rocky desertification’ dominates. Through the establishment of the “Soil processes and ecological services in the karst critical zone of SW China” (SPECTRA) Critical Zone Observatory (CZO) we will endevaour to understand the fundmental processes involved in soil production and erosion, and investigate the integrated geophysical-geochemical-ecological responses of the CZ to perturbations. The CZ spans a gradient from undisturbed natural vegetation through human perturbed landscapes. We seek to understand the importance of heterogeneity in surface and below-ground morphology and flow pathways in determining the spatial distribution of key stocks (soil, C, vegetation, etc.) and their control on ecosystem service delivery. We will assess the extent to which the highly heterogeneous critical zone resources can be restored to enable sustainable delivery of ecosystem services. This paper presents the CZO design and initial assessment of soil and soil organic carbon stocks and evidence for their stability based on caesium-137 (137Cs) data.
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    Future C loss in mid-latitude mineral soils: climate change exceeds land use mitigation potential in France
    (Nature Publishing Group, 2016-11-03) Meersmans, Jeroen; Arrouays, Dominique; van Rompaey, Anton; Pagé, Christian; De Baets, Sarah; Quine, Timothy
    Many studies have highlighted significant interactions between soil C reservoir dynamics and global climate and environmental change. However, in order to estimate the future soil organic carbon sequestration potential and related ecosystem services well, more spatially detailed predictions are needed. The present study made detailed predictions of future spatial evolution (at 250 m resolution) of topsoil SOC driven by climate change and land use change for France up to the year 2100 by taking interactions between climate, land use and soil type into account. We conclude that climate change will have a much bigger influence on future SOC losses in mid-latitude mineral soils than land use change dynamics. Hence, reducing CO2 emissions will be crucial to prevent further loss of carbon from our soils.
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    Rock crevices determine woody and herbaceous plant cover in the karst critical zone
    (Springer, 2019-03-07) Liu, Hongyan; Jiang, Zihan; Dai, Jingxi; Wu, Xiuchen; Jian, Peng; Hongya, Wang; Jereon, Meersmans; Green, Sophie M.; Quine, Timothy
    The study of the critical zones (CZs) of the Earth link the composition and function of aboveground vegetation with the characteristics of the rock layers, providing a new way to study how the unique rock and soil conditions in karst regions affect the aboveground vegetation. Based on survey results of the rocks, soils and vegetation in the dolomite and limestone distribution areas in the karst area of central Guizhou, it was found that woody plant cover increases linearly with the number of cracks with a width of more than 1 mm, while the cover of herbaceous plants shows the opposite trend (p<0.01). The dolomite distribution area is characterized by undeveloped crevices, and the thickness of the soil layer is generally less than 20 cm, which is suitable for the distribution of herbaceous plants with shallow roots. Due to the development of crevices in the limestone distribution area, the soil is deeply distributed through the crevices for the deep roots of trees, which leads to a diversified species composition and a complicated structure in the aboveground vegetation. Based on moderate resolution imaging spectroradiometer (MODIS) remote sensing data from 2001 to 2010, the normalized differentiated vegetation index (NDVI) and annual net primary productivity (NPP) results for each phase of a 16-day interval further indicate that the NDVI of the limestone distribution area is significantly higher than that in the dolomite distribution area, but the average annual NPP is the opposite. The results of this paper indicate that in karst CZs, the lithology determines the structure and distribution of the soil, which further determines the cover of woody and herbaceous plants in the aboveground vegetation. Although the amount of soil in the limestone area may be less than that in the dolomite area, the developed crevice structure is more suitable for the growth of trees with deep roots, and the vegetation activity is strong. At present, the treatment of rocky desertification in karst regions needs to fully consider the rock-soilvegetation- air interactions in karst CZs and propose vegetation restoration measures suitable for different lithologies.
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    Testing the utility of structure from motion photogrammetry reconstructions using small unmanned aerial vehicles and ground photography to estimate the extent of upland soil erosion
    (Wiley, 2017-03-08) Glendell, Miriam; McShane, Gareth; Farrow, Luke; James, Mike R.; Quinton, John Norman; Anderson, Karen; Evans, Martin; Benaud, Pia; Rawlins, Barry; Morgan, David; Jones, Lee; Kirkham, Matthew; DeBell, Leon; Quine, Timothy; Lark, Murray; Rickson, R. Jane; Brazier, Richard E.
    Quantifying the extent of soil erosion at a fine spatial resolution can be time consuming and costly; however, proximal remote sensing approaches to collect topographic data present an emerging alternative for quantifying soil volumes lost via erosion. Herein we compare terrestrial laser scanning (TLS), and both aerial (UAV) and ground-based (GP) SfM derived topography. We compare the cost-effectiveness and accuracy of both SfM techniques to TLS for erosion gully surveying in upland landscapes, treating TLS as a benchmark. Further, we quantify volumetric soil loss estimates from upland gullies using digital surface models derived by each technique and subtracted from an interpolated pre-erosion surface. Soil loss estimates from UAV and GP SfM reconstructions were comparable to those from TLS, whereby the slopes of the relationship between all three techniques were not significantly different from 1:1 line. Only for the TLS to GP comparison the intercept was significantly different from zero, showing that GP is more capable of measuring the volumes of very small erosion features. In terms of cost-effectiveness in data collection and processing time, both UAV and GP were comparable with the TLS on a per-site basis (13.4 and 8.2 person-hours versus 13.4 for TLS); however GP was less suitable for surveying larger areas (127 person-hours per ha-1 versus 4.5 for UAV and 3.9 for TLS). Annual repeat surveys using GP were capable of detecting mean vertical erosion change on peaty soils. These first published estimates of whole gully erosion rates (0.077 m a-1) suggest that combined erosion rates on gully floors and walls are around three times the value of previous estimates, which largely characterise wind and rainsplash erosion of gully walls.
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    Tracing of particulate organic C sources across the terrestrial-aquatic continuum, a case study at the catchment scale (Carminowe Creek, southwest England)
    (Elsevier, 2017-11-06) Glendell, M.; Jones, R.; Dungait, J. A. J.; Meusburger, K.; Schwendel, A. C.; Barclay, R.; Barker, Sam; Haley, S.; Quine, Timothy; Meersmans, Jeroen
    Soils deliver crucial ecosystem services, such as climate regulation through carbon (C) storage and food security, both of which are threatened by climate and land use change. While soils are important stores of terrestrial C, anthropogenic impact on the lateral fluxes of C from land to water remains poorly quantified and not well represented in Earth system models. In this study, we tested a novel framework for tracing and quantifying lateral C fluxes from the terrestrial to the aquatic environment at a catchment scale. The combined use of conservative plant-derived geochemical biomarkers n-alkanes and bulk stable δ13C and δ15N isotopes of soils and sediments allowed us to distinguish between particulate organic C sources from different land uses (i.e. arable and temporary grassland vs. permanent grassland vs. riparian woodland vs. river bed sediments) (p < 0.001), showing an enhanced ability to distinguish between land use sources as compared to using just n-alkanes alone. The terrestrial-aquatic proxy (TAR) ratio derived from n-alkane signatures indicated an increased input of terrestrial-derived organic matter (OM) to lake sediments over the past 60 years, with an increasing contribution of woody vegetation shown by the C27/C31 ratio. This may be related to agricultural intensification, leading to enhanced soil erosion, but also an increase in riparian woodland that may disconnect OM inputs from arable land uses in the upper parts of the study catchment. Spatial variability of geochemical proxies showed a close coupling between OM provenance and riparian land use, supporting the new conceptualization of river corridors (active river channel and riparian zone) as critical zones linking the terrestrial and aquatic C fluxes. Further testing of this novel tracing technique shows promise in terms of quantification of lateral C fluxes as well as targeting of effective land management measures to reduce soil erosion and promote OM conservation in river catchments.