The impact of grazing on spatial variability of humus profile properties in a grass-encroached Scots pine ecosystem

Abstract. Spatial variability in snowpack properties negatively impacts our capacity to make direct measurements of snow water equivalent (SWE) using satellites. A comprehensive data set of snow microstructure (94 profiles at 36 sites) and snow layer thickness (9000 vertical profiles across nine trenches) collected over two winters at Trail Valley Creek, NWT, Canada, was applied in synthetic radiative transfer experiments. This allowed for robust assessment of the impact of estimation accuracy of unknown snow microstructural characteristics on the viability of SWE retrievals. Depth hoar layer thickness varied over the shortest horizontal distances, controlled by subnivean vegetation and topography, while variability in total snowpack thickness approximated that of wind slab layers. Mean horizontal correlation lengths of layer thickness were less than a metre for all layers. Depth hoar was consistently ∼30 % of total depth, and with increasing total depth the proportion of wind slab increased at the expense of the decreasing surface snow layer. Distinct differences were evident between distributions of layer properties; a single median value represented density and specific surface area (SSA) of each layer well. Spatial variability in microstructure of depth hoar layers dominated SWE retrieval errors. A depth hoar SSA estimate of around 7 % under the median value was needed to accurately retrieve SWE. In shallow snowpacks <0.6 m, depth hoar SSA estimates of ±5 %–10 % around the optimal retrieval SSA allowed SWE retrievals within a tolerance of ±30 mm. Where snowpacks were deeper than ∼30 cm, accurate values of representative SSA for depth hoar became critical as retrieval errors were exceeded if the median depth hoar SSA was applied.

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Regionalized Terrestrial Ecotoxicity Assessment of Copper-Based Fungicides Applied in Viticulture

Sustainability ◽

10.3390/su10072522 ◽

2018 ◽

Vol 10 (7) ◽

pp. 2522 ◽

Cited By ~ 5

Author(s):

Ivan Viveros Santos ◽

Cécile Bulle ◽

Annie Levasseur ◽

Louise Deschênes

Keyword(s):

Spatial Variability ◽

Soil Properties ◽

Regression Models ◽

Management Practices ◽

Metal Speciation ◽

Agricultural Systems ◽

Geographical Variability ◽

Terrestrial Ecotoxicity ◽

The Impact ◽

Growing Region

Life cycle assessment has been recognized as an important decision-making tool to improve the environmental performance of agricultural systems. Still, there are certain modelling issues related to the assessment of their impacts. The first is linked to the assessment of the metal terrestrial ecotoxicity impact, for which metal speciation in soil is disregarded. In fact, emissions of metals in agricultural systems contribute significantly to the ecotoxic impact, as do copper-based fungicides applied in viticulture to combat downy mildew. Another issue is linked to the ways in which the intrinsic geographical variability of agriculture resulting from the variation of management practices, soil properties, and climate is addressed. The aim of this study is to assess the spatial variability of the terrestrial ecotoxicity impact of copper-based fungicides applied in European vineyards, accounting for both geographical variability in terms of agricultural practice and copper speciation in soil. This first entails the development of regionalized characterization factors (CFs) for the copper used in viticulture and then the application of these CFs to a regionalized life-cycle inventory that considers different management practices, soil properties, and climates in different regions, namely Languedoc-Roussillon (France), Minho (Portugal), Tuscany (Italy), and Galicia (Spain). There are two modelling alternatives to determine metal speciation in terrestrial ecotoxicity: (a) empirical regression models; and (b) WHAM 6.0, the geochemical speciation model applied according to the soil properties of the Harmonized World Soil Database (HWSD). Both approaches were used to compute and compare regionalized CFs with each other and with current IMPACT 2002+ CF. The CFs were then aggregated at different spatial resolutions—global, Europe, country, and wine-growing region—to assess the uncertainty related to spatial variability at the different scales and applied in the regionalized case study. The global CF computed for copper terrestrial ecotoxicity is around 3.5 orders of magnitude lower than the one from IMPACT 2002+, demonstrating the impact of including metal speciation. For both methods, an increase in the spatial resolution of the CFs translated into a decrease in the spatial variability of the CFs. With the exception of the aggregated CF for Portugal (Minho) at the country level, all the aggregated CFs derived from empirical regression models are greater than the ones derived from the method based on WHAM 6.0 within a range of 0.2 to 1.2 orders of magnitude. Furthermore, CFs calculated with empirical regression models exhibited a greater spatial variability with respect to the CFs derived from WHAM 6.0. The ranking of the impact scores of the analyzed scenarios was mainly determined by the amount of copper applied in each wine-growing region. However, finer spatial resolutions led to an impact score with lower uncertainty.

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Invasive Scots Pine, Pinus sylvestris, Replacing Corema, Corema conradii, Heathland in the Annapolis Valley, Nova Scotia

The Canadian Field-Naturalist ◽

10.22621/cfn.v119i2.112 ◽

2005 ◽

Vol 119 (2) ◽

pp. 237 ◽

Cited By ~ 5

Author(s):

Paul M. Catling ◽

Susan Carbyn

Keyword(s):

Pinus Sylvestris ◽

Scots Pine ◽

Vascular Plants ◽

Dominant Species ◽

Vascular Plant ◽

Agricultural Crops ◽

Deschampsia Flexuosa ◽

Natural Habitats ◽

Annapolis Valley ◽

The Impact

Examination of air photos from 1930, 1970 and 2002 revealed stands of the European Scots Pine (Pinus sylvestris) invading remnants of natural Corema (Corema conradii) heathland in the Annapolis valley. To document the impact of the introduced pines, four natural habitats were compared with two adjacent habitats already invaded by the pines. All surveyed habitats had been dominated by Corema heath based on air photos taken in 1930. Twenty 1 m2 quadrats were used to record presence and cover of vascular plants at each site. The invasive alien pines reduce the native cover to 12%. Vascular plant biodiversity is reduced to less than 42% and the cover of the heathland dominant, Corema conradii, is reduced from over 100 % to less than 2%. with Deschampsia flexuosa becoming the dominant species. The modified ecosystem and loss of biodiversity has economic impacts through loss of pollinators of agricultural crops and loss of germplasm of native crop relatives.

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Iron-bound organic carbon in forest soils: quantification and characterization

Biogeosciences ◽

10.5194/bg-13-4777-2016 ◽

2016 ◽

Vol 13 (16) ◽

pp. 4777-4788 ◽

Cited By ~ 52

Author(s):

Qian Zhao ◽

Simon R. Poulson ◽

Daniel Obrist ◽

Samira Sumaila ◽

James J. Dynes ◽

...

Keyword(s):

Organic Carbon ◽

Spatial Variability ◽

Forest Soils ◽

The United States ◽

Biogeochemical Cycles ◽

Mean Annual Temperature ◽

Aliphatic Carbon ◽

A Site ◽

The Impact ◽

X Ray Absorption

Abstract. Iron oxide minerals play an important role in stabilizing organic carbon (OC) and regulating the biogeochemical cycles of OC on the earth surface. To predict the fate of OC, it is essential to understand the amount, spatial variability, and characteristics of Fe-bound OC in natural soils. In this study, we investigated the concentrations and characteristics of Fe-bound OC in soils collected from 14 forests in the United States and determined the impact of ecogeographical variables and soil physicochemical properties on the association of OC and Fe minerals. On average, Fe-bound OC contributed 37.8 % of total OC (TOC) in forest soils. Atomic ratios of OC : Fe ranged from 0.56 to 17.7, with values of 1–10 for most samples, and the ratios indicate the importance of both sorptive and incorporative interactions. The fraction of Fe-bound OC in TOC (fFe-OC) was not related to the concentration of reactive Fe, which suggests that the importance of association with Fe in OC accumulation was not governed by the concentration of reactive Fe. Concentrations of Fe-bound OC and fFe-OC increased with latitude and reached peak values at a site with a mean annual temperature of 6.6 °C. Attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) and near-edge X-ray absorption fine structure (NEXAFS) analyses revealed that Fe-bound OC was less aliphatic than non-Fe-bound OC. Fe-bound OC also was more enriched in 13C compared to the non-Fe-bound OC, but C ∕ N ratios did not differ substantially. In summary, 13C-enriched OC with less aliphatic carbon and more carboxylic carbon was associated with Fe minerals in the soils, with values of fFe-OC being controlled by both sorptive and incorporative associations between Fe and OC. Overall, this study demonstrates that Fe oxides play an important role in regulating the biogeochemical cycles of C in forest soils and uncovers the governing factors for the spatial variability and characteristics of Fe-bound OC.

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Mesoscale Spatial Variability of Linear Trend of Precipitation Statistics in Korean Peninsula

Advances in Meteorology ◽

10.1155/2016/3809719 ◽

2016 ◽

Vol 2016 ◽

pp. 1-15 ◽

Cited By ~ 3

Author(s):

Jaehyeon Lee ◽

Jaehyun Ahn ◽

Eunsoo Choi ◽

Dongkyun Kim

Keyword(s):

Spatial Variability ◽

Korean Peninsula ◽

Temporal Trend ◽

Linear Trend ◽

Kendall Test ◽

Characteristic Scale ◽

Management Plans ◽

The Impact ◽

Mean Variance ◽

Approximate Characteristic

This study analyzed the spatial variability of the linear trend of the precipitation mean, variance, lag-1 autocorrelation coefficient, and probability of dryness (PD) based on the precipitation data between 1981 and 2015 observed at 65 rain gages located across Korean Peninsula. While the result of the Mann-Kendall test based on the yearly statistics showed no temporal trend at most of the gage locations, the same test based on the 20-yearly statistics showed that statistically significant temporal trend exists at 54% (mean), 60% (variance), 61% (autocorrelation), and 61% (PD) among the total 65 rain gages. In addition, this study produced the map of the linear trend of the precipitation statistics. The map showed a clear regional and seasonal tendency implying that the impact of the climate change varies significantly within Korea. The variogram analysis revealed that the approximate characteristic scale of linear trend of hourly and daily precipitation statistics ranges between 50 km and 200 km and between 100 km and 250 km, respectively. This characteristic scale is significantly smaller than the spatial scale of atmospheric circulation, which suggests that future water resources management plans of Korea should consider this mesoscale variability that otherwise can be missed if it is based only on the GCM simulation results.

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Bestandesdynamik zentralalpiner Waldföhrenwälder aufgezeigt anhand dendroökologischer Fallstudien aus dem Wallis, Schweiz | Stand dynamics of central alpine Scots pine using dendroecological case studies from Valais, Switzerland

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2004.0178 ◽

2004 ◽

Vol 155 (6) ◽

pp. 178-190 ◽

Cited By ~ 11

Author(s):

Andreas Rigling ◽

Pascale Weber ◽

Paolo Cherubini ◽

Matthias Dobbertin

Keyword(s):

Case Studies ◽

Scots Pine ◽

Forest Dynamics ◽

Abiotic Factors ◽

Pine Forests ◽

Natural Disturbances ◽

Development History ◽

History Of ◽

Scots Pine Forests ◽

The Impact

The aim of this paper is to demonstrate the use of dendroecological methods to analyse the various processes involved in forest dynamics. Using dendroecological case studies of the Scots pine forests of Valais (Switzerland) as an example we discuss the most relevant processes of forest dynamics and their consequences on stand structures and mortality rates. We focus on the development history of these Scots pine forests under human impact and on the impact of biotic and abiotic factors on tree growth. Most of today's extended Scots pine forests (< 1500 m a.s.l.)must be interpreted as part of an ongoing natural succession under heavy human influence. In time, without management or natural disturbances, most of these pine forests will develop into broadleaved forests (lower altitudes) or spruce-firforests(higher altitudes).

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Space variability of hydrological responses of Nature-Based Solutions and the resulting uncertainty

10.5194/hess-2020-468 ◽

2020 ◽

Author(s):

Yangzi Qiu ◽

Igor da Silva Rocha Paz ◽

Feihu Chen ◽

Pierre-Antoine Versini ◽

Daniel Schertzer ◽

...

Keyword(s):

Spatial Variability ◽

Peak Flow ◽

Hydrological Cycle ◽

Green Roof ◽

Spatial Arrangement ◽

Intersection Theorem ◽

Runoff Volume ◽

Hydrological Responses ◽

Total Runoff ◽

The Impact

Abstract. During the last decades, the urban hydrological cycle has been strongly modified by the built environment, resulting in fast runoff and increasing the risk of waterlogging. Nature-Based Solutions (NBS), which apply green infrastructures, have been more and more widely considered as a sustainable approach for urban stormwater management. However, the assessment of NBS performance still requires further modelling development because of their hydrological responses sensitively depends on the representation of multiscale space variability of both the rainfall and the NBS distribution. Indeed, we initially argue this issue with the help of the multifractal intersection theorem. To illustrate the importance of this question, the spatial heterogeneous distributions of two series of NBS scenarios (porous pavement, rain garden, green roof, and combined) are quantified with the help of their fractal dimension. We point out consequences of their estimates. Then, a fully-distributed and physically-based hydrological model (Multi-Hydro) was applied to consider the studied catchment and these NBS scenarios with a spatial resolution of 10 m under two different types of rainfall: distributed and uniform, and for three rainfall events. These simulations show that the impact of spatial variability of rainfall on the uncertainty of peak flow of NBS scenarios ranges from about 8 % to 17 %, which is more pronounced than those of the total runoff volume. In addition, the spatial variability of the rainfall intensity at the largest rainfall peak responds almost linearly to the uncertainty of the peak flow of NBS scenarios. However, the hydrological responses of NBS scenarios are less affected by the spatial distribution of NBS. Finally, the intersection effects of the spatial variability of rainfall and the spatial arrangement of NBS seem more pronounced for the peak flow of green roof scenarios and the total runoff volume of combined scenarios.

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