The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
David A Wardle - One of the best experts on this subject based on the ideXlab platform.
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coordinated responses of soil communities to elevation in three subarctic Vegetation Types
Oikos, 2017Co-Authors: G F Veen, Jonathan R De Long, Paul Kardol, Maja K Sundqvist, Basten L Snoek, David A WardleAbstract:Global warming has begun to have a major impact on the species composition and functioning of plant and soil communities. However, long-term community and ecosystem responses to increased temperature are still poorly understood. In this study, we used a well-established elevational gradient in northern Sweden to elucidate how plant, microbial and nematode communities shift with elevation and associated changes in temperature in three highly contrasting Vegetation Types (i.e. heath, meadow and Salix Vegetation). We found that responses of both the abundance and composition of microbial and nematode communities to elevation differed greatly among the Vegetation Types. Within Vegetation Types, changes with elevation of plant, microbial and nematode communities were mostly linked at fine levels of taxonomic resolution, but this pattern disappeared when coarser functional group levels were considered. Further, nematode communities shifted towards more conservative nutrient cycling strategies with increasing elevation in heath and meadow Vegetation. Conversely, in Salix Vegetation microbial communities with conservative strategies were most pronounced at the mid-elevation. These results provide limited support for increasing conservative nutrient cycling strategies at higher elevation (i.e. with a harsher climate). Our findings indicate that climate-induced changes in plant community composition may greatly modify or counteract the impact of climate change on soil communities. Therefore, to better understand and predict ecosystem responses to climate change, it will be crucial to consider Vegetation type and its specific interactions with soil communities.
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within and across species responses of plant traits and litter decomposition to elevation across contrasting Vegetation Types in subarctic tundra
PLOS ONE, 2011Co-Authors: Maja K Sundqvist, Reiner Giesler, David A WardleAbstract:Elevational gradients are increasingly recognized as a valuable tool for understanding how community and ecosystem properties respond to climatic factors, but little is known about how plant traits and their effects on ecosystem processes respond to elevation. We studied the response of plant leaf and litter traits, and litter decomposability across a gradient of elevation, and thus temperature, in subarctic tundra in northern Sweden for each of two contrasting Vegetation Types, heath and meadow, dominated by dwarf shrubs and herbaceous plants respectively. This was done at each of three levels; across species, within individual species, and the plant community using a community weighted average approach. Several leaf and litter traits shifted with increasing elevation in a manner consistent with greater conservation of nutrients at all three levels, and the most consistent response was an increase in tissue N to P ratio. However, litter decomposition was less directly responsive to elevation because the leaf and litter traits which were most responsive to elevation were not necessarily those responsible for driving decomposition. At the community level, the response to elevation of foliar and litter traits, and decomposability, varied greatly among the two Vegetation Types, highlighting the importance of Vegetation type in determining ecological responses to climatic factors such as temperature. Finally our results highlight how understanding the responses of leaf and litter characteristics of functionally distinct Vegetation Types, and the processes that they drive, to temperature helps provide insights about how future climate change could affect tundra ecosystems.
Peter J. Edwards - One of the best experts on this subject based on the ideXlab platform.
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differential air temperature cooling performance of urban Vegetation Types in the tropics
Urban Forestry & Urban Greening, 2020Co-Authors: Tze Kwan Fung, Richard N Belcher, Peter J. EdwardsAbstract:Abstract The tendency for cities to be warmer than surrounding rural areas, known as the urban heat island effect, has become a matter of increasing concern, particularly in regions with a hot, humid climate. While urban Vegetation may reduce air temperatures, the magnitude of this cooling effect varies between different Types of Vegetation. In this study we compared the cooling effect of five Vegetation Types that are commonly encountered in the tropical city of Singapore: grass, shrub, managed trees, managed trees over shrub, and secondary forest. Ambient air temperatures were monitored over 18 months at 88 locations, and analysed in relation to characteristics of the surrounding Vegetation. Generalised additive modelling revealed significant temperature reductions associated with increasing cover of managed trees, managed trees over shrubs below, and secondary forest Vegetation, with the latter Vegetation type having the greatest effect. We conclude that Vegetation can significantly ameliorate temperatures in cities with a hot, humid climate, but not all Types of Vegetation are equally effective. By demonstrating the cooling benefits of secondary forest in densely-populated urban areas, public education and engagement campaigns could help overcome negative perceptions of such Vegetation.
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Urban Vegetation Types are Not Perceived Equally in Providing Ecosystem Services and Disservices
Sustainability, 2020Co-Authors: Zuzana Drillet, Tze Kwan Fung, Rachel A. T. Leong, Uma Sachidhanandam, Peter J. Edwards, Daniel R. RichardsAbstract:Urban Vegetation is important in providing ecosystem services to people. Different urban Vegetation Types provide contrasting suites of ecosystem services and disservices. Understanding public perceptions of the ecosystem services and disservices can therefore play an important role in shaping the planning and management of urban areas. We conducted an online survey (n = 1000) to understand how residents in the tropical city of Singapore perceived urban Vegetation and the associated ecosystem services and disservices. The questionnaire was designed to explore whether different urban Vegetation Types (grass, shrubs, trees, trees over shrubs, and secondary forest) were perceived as equal in providing benefits. Respondents considered ecosystem services provided by urban Vegetation to be more important than disservices. Among ecosystem services, regulating services were most highly rated, with more than 80% of the respondents appreciating urban Vegetation for providing shade and improving air quality. Respondents recognized that different Vegetation Types provided different ecosystem services. For example, secondary forest was most commonly associated with education and wildlife, while trees were strongly associated with cooling and air quality. We conclude that in developing plans and designs for urban Vegetation and ecosystem services, it is important to understand the perceptions, priorities, and concerns of residents.
Sven Jonasson - One of the best experts on this subject based on the ideXlab platform.
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temperature and substrate controls on intra annual variation in ecosystem respiration in two subarctic Vegetation Types
Global Change Biology, 2005Co-Authors: Paul Grogan, Sven JonassonAbstract:Arctic ecosystems are important in the context of climate change because they are expected to undergo the most rapid temperature increases, and could provide a globally significant release of CO2 to the atmosphere from their extensive bulk soil organic carbon reserves. Understanding the relative contributions of bulk soil organic matter and plant-associated carbon pools to ecosystem respiration is critical to predicting the response of arctic ecosystem net carbon balance to climate change. In this study, we determined the variation in ecosystem respiration rates from birch forest understory and heath tundra Vegetation Types in northern Sweden through a full annual cycle. We used a plant biomass removal treatment to differentiate bulk soil organic matter respiration from total ecosystem respiration in each Vegetation type. Plant-associated and bulk soil organic matter carbon pools each contributed significantly to ecosystem respiration during most phases of winter and summer in the two Vegetation Types. Ecosystem respiration rates through the year did not differ significantly between Vegetation Types despite substantial differences in biomass pools, soil depth and temperature regime. Most (76‐92%) of the intra-annual variation in ecosystem respiration rates from these two common mesic subarctic ecosystems was explained using a first-order exponential equation relating respiration to substrate chemical quality and soil temperature. Removal of plants and their current year’s litter significantly reduced the sensitivity of ecosystem respiration to intra-annual variations in soil temperature for both Vegetation Types, indicating that respiration derived from recent plant carbon fixation was more temperature sensitive than respiration from bulk soil organic matter carbon stores. Accurate assessment of the potential for positive feedbacks from high-latitude ecosystems to CO2-induced climate change will require the development of ecosystemlevel physiological models of net carbon exchange that differentiate the responses of major C pools, that account for effects of Vegetation type, and that integrate over summer and winter seasons.
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trace gas exchange in a high arctic valley 1 variations in co2 and ch4 flux between tundra Vegetation Types
Global Biogeochemical Cycles, 2000Co-Authors: Torben R Christensen, Lotte Illeris, Thomas Friborg, M Sommerkorn, Jed O Kaplan, H Soegaard, Claus Nordstroem, Sven JonassonAbstract:Ecosystem exchanges of CO2 and CH4 were studied by chamber techniques in five different Vegetation Types in a high arctic valley at Zackenberg, NE Greenland. The Vegetation Types were categorized as Cassiope heath, hummocky fen, continuous fen, grass land and Salix arctica snowbed. Integrated daytime fluxes for the different Vegetation Types of the valley showed that the fen areas and the grassland, were significant sources of CH4 with a mean efflux of 6.3 mg CH4 m(-2) h(-1) and sinks for CO2, with almost -170 mg CO2 m(-2) hr(-1). The heath and snowbed areas had much lower carbon sequestration rates of about -25 mg CO2 m(-2) hr(-1) and were also sinks for CH4. Methane emissions from the valley dominated in the hummocky fens. Computation of area integrated mean daytime flux values across all Vegetation Types of the entire valley bottom revealed that it was a sink of CO2 in the order of -96+/-33 mg CO2 m-2 hr-1 and a source of 1.9+/-0.7 m(-2) CH4 m(-2) hr(-1). These values were in accordance with eddy correlation measurements reported elsewhere in this issue and reflect a high-carbon exchange despite the high arctic location. In the fens, where the water table was at or above the soil surface, methane emissions increased with net ecosystem CO2 flux. In places with the water table below the soil surface, such as particularly in the hummocky parts of the fen, oxidation tended to become the dominant controlling factor on methane efflux.
Mingan Shao - One of the best experts on this subject based on the ideXlab platform.
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three dimensional quantification of soil pore structure in wind deposited loess under different Vegetation Types using industrial x ray computed tomography
Catena, 2021Co-Authors: Jiangbo Qiao, Mingan Shao, Xingting Liu, Yuanjun Zhu, Xiaoxu JiaAbstract:Abstract Quantifying the soil pore structure is critical for understanding plant growth and water/solute movements in the soil. However, most previous studies quantified the soil pore structure in a shallow layer by using low resolution medical computed tomography (CT), whereas few have quantified the soil pore structure in deep soil layers with high resolution CT. In this study, we quantified the soil pore structure of wind-deposited loess under different Vegetation Types (wheat, weeds, apple orchard, and Robinia pseudoacacia) at depths from 0 to 4.5 m by industrial CT. The results showed that the soil pore number and porosity tended to decreased with depth, but there were no significance differences below 2 m among all Vegetation Types. For different depths and Vegetation Types, the number of pores measuring 0–100 μm was highest, followed by those measuring. 100–500 μm, and lowest for those measuring > 1000 μm. The contribution of pores measuring 100–500 μm to the total pore volume was highest. The variations in the connectivity and surface area density were also focused mainly within the depth down to 2 m, and the variations were minor below 2 m. There were no significant differences in the bulk density and soil pore characteristics under different Vegetation Types, except for weeds. The results obtained in this study provide insights into the interactions between Vegetation and soil water, as well as the hydrological processes for the wind-deposited loess.
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response of soil water dynamics to precipitation years under different Vegetation Types on the northern loess plateau china
Journal of Arid Land, 2016Co-Authors: Bingxia Liu, Mingan ShaoAbstract:Implementation of the Grain-for-Green project has led to rapid land cover changes and resulted in a significantly increased Vegetation cover on the Loess Plateau of China during the past few decades. The main objective of this study was to examine the responses of soil water dynamics under four typical Vegetation Types against precipitation years. Soil water contents (SWCs) were measured in 0–4.0 m profiles on a hillslope under the four Vegetation Types of shrub, pasture, natural fallow and crop in a re-vegetated catchment area from April to October in normal (2010), dry (2011), wet (2014) and extremely wet (2013) years. The results indicated that precipitation and Vegetation Types jointly controlled the soil water temporal dynamics and profile characteristics in the study region. SWCs in 0–4.0 m profiles of the four Vegetation Types were ranked from high to low as crop>fallow>pasture>shrub and this pattern displayed a temporal stability over the four years. In the extremely wet year, SWC changes occurred in the 0–2.0 m layer under shrub and pasture while the changes further extended to the depth of 4.0-m deep layers under fallow and crop. In the other three years, SWCs changes mainly occurred in the 0–1.0 m layer and kept relatively stable in the layers deeper than 1.0 m for all the four Vegetation Types. The interannual variation in soil depth of SWCs was about 0–2.0 m for shrub and pasture, about 0–3.4 m for fallow and about 0–4.0 m for crop, respectively. The dried soil layers formed at the depths of 1.0, 0.6, 1.6 and 0.7 m under shrub, and 1.0, 1.0, 2.0 and 0.9 m under pasture, respectively in 2010, 2011, 2013 and 2014. The infiltrated rainwater mostly stayed in the 0–1.0 m layer and hardly supplied to soil depth >1.0 m in normal, dry and wet years. Even in the extremely wet year of 2013, rainwater recharge depth did not exceed 2.0 m under shrub and pasture. This implied that soil desiccation was difficult to remove in normal, dry and wet years, and soil desiccation could be removed in 1.0–2.0 m soil layers even in the extremely wet year under shrub and pasture. The results indicated that the natural fallow was the best Vegetation type for achieving sustainable utilization of soil water and preventing soil desiccation.
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soil organic carbon and total nitrogen as affected by Vegetation Types in northern loess plateau of china
Geoderma, 2010Co-Authors: Xiaoli Fu, Mingan Shao, Robert HortonAbstract:One of the most fragile areas in the China Loess Plateau, is the transitional belt that is subjected to wind and water erosion. The transitional belt accounts for about 30% of the Loess Plateau area. To reduce soil degradation in the Loess Plateau, the Chinese government initiated a state-funded Vegetation restoration project in 1999. The effectiveness of this project on transitional belt soils is unknown. The objective of this study is to determine the effects of four dominant Vegetation Types on soil organic carbon (SOC) and nitrogen (N) in a selected catchment within the transitional belt. Korshinsk Peashrub (KOP), purple alfalfa (ALF). and natural fallow (NAF) were selected as Vegetation restoration Types because they have been used widely to remedy soil degradation. The fourth Vegetation type selected was millet (MIL) because it has been an important crop in the region. In 2004, four 61 x 5 m plots were established on 12 degrees slope land. The plots were parallel and separated by 80 cm. Based upon soil samples collected in August of 2007, there were large variations in the distributions and stocks of SOC and N across the four Vegetation Types. Compared with MIL, KOP significantly increased the concentration and stock of SOC and total nitrogen (TN) in 0-100 cm soil profiles, while ALF and NAF were not significantly different. The distributions of SOC and TIN concentrations and stocks of KOP, ALF and NAF were relatively uniform along a hillslope, while there was an increasing trend along the hillslope in MIL This result suggests that ALF and NAF would be beneficial in SOC and TN sequestration over a long-term because of their ability to reduce the loss of SOC and TN by soil erosion. We also found that both Vegetation Types and hillslope position had no significant effects on C:N ratio. Our Study demonstrated that improvements of SOC and TN stocks in the transitional belt could be made through well managed Vegetation restoration measures. (C) 2009 Published by Elsevier B.V.
Tze Kwan Fung - One of the best experts on this subject based on the ideXlab platform.
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differential air temperature cooling performance of urban Vegetation Types in the tropics
Urban Forestry & Urban Greening, 2020Co-Authors: Tze Kwan Fung, Richard N Belcher, Peter J. EdwardsAbstract:Abstract The tendency for cities to be warmer than surrounding rural areas, known as the urban heat island effect, has become a matter of increasing concern, particularly in regions with a hot, humid climate. While urban Vegetation may reduce air temperatures, the magnitude of this cooling effect varies between different Types of Vegetation. In this study we compared the cooling effect of five Vegetation Types that are commonly encountered in the tropical city of Singapore: grass, shrub, managed trees, managed trees over shrub, and secondary forest. Ambient air temperatures were monitored over 18 months at 88 locations, and analysed in relation to characteristics of the surrounding Vegetation. Generalised additive modelling revealed significant temperature reductions associated with increasing cover of managed trees, managed trees over shrubs below, and secondary forest Vegetation, with the latter Vegetation type having the greatest effect. We conclude that Vegetation can significantly ameliorate temperatures in cities with a hot, humid climate, but not all Types of Vegetation are equally effective. By demonstrating the cooling benefits of secondary forest in densely-populated urban areas, public education and engagement campaigns could help overcome negative perceptions of such Vegetation.
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Urban Vegetation Types are Not Perceived Equally in Providing Ecosystem Services and Disservices
Sustainability, 2020Co-Authors: Zuzana Drillet, Tze Kwan Fung, Rachel A. T. Leong, Uma Sachidhanandam, Peter J. Edwards, Daniel R. RichardsAbstract:Urban Vegetation is important in providing ecosystem services to people. Different urban Vegetation Types provide contrasting suites of ecosystem services and disservices. Understanding public perceptions of the ecosystem services and disservices can therefore play an important role in shaping the planning and management of urban areas. We conducted an online survey (n = 1000) to understand how residents in the tropical city of Singapore perceived urban Vegetation and the associated ecosystem services and disservices. The questionnaire was designed to explore whether different urban Vegetation Types (grass, shrubs, trees, trees over shrubs, and secondary forest) were perceived as equal in providing benefits. Respondents considered ecosystem services provided by urban Vegetation to be more important than disservices. Among ecosystem services, regulating services were most highly rated, with more than 80% of the respondents appreciating urban Vegetation for providing shade and improving air quality. Respondents recognized that different Vegetation Types provided different ecosystem services. For example, secondary forest was most commonly associated with education and wildlife, while trees were strongly associated with cooling and air quality. We conclude that in developing plans and designs for urban Vegetation and ecosystem services, it is important to understand the perceptions, priorities, and concerns of residents.
