Influence of shrub encroachment on aboveground net primary productivity and carbon and nitrogen pools in a mesic grassland

2004 ◽  
Vol 82 (9) ◽  
pp. 1363-1370 ◽  
Author(s):  
Michelle S Lett ◽  
Alan K Knapp ◽  
John M Briggs ◽  
John M Blair
Keyword(s):  
Tallgrass Prairie ◽  
Primary Productivity ◽  
Aboveground Biomass ◽  
Net Primary Productivity ◽  
Shrub Encroachment ◽  
Organic C ◽  
Mesic Grassland ◽  
C And N ◽  
Cornus Drummondii ◽  
The Impact

The clonal shrub Cornus drummondii C.A. Mey. is rapidly increasing in cover and displacing mesic grassland species in the central USA as a consequence of fire suppression. We assessed the impact of C. drummondii on carbon (C) and nitrogen (N) pools and C fluxes in a tallgrass prairie in eastern Kansas, USA, through a comparison of both burned and unburned C. drummondii islands with open grassland areas. Allometric equations relating C. drum mondii foliage and wood biomass to basal stem diameter were developed to estimate aboveground biomass and net primary productivity (ANPP) of C. drummondii. Within C. drummondii islands, ANPP was 496 ± 45 g C·m–2·year–1, nearly three times that within open grassland (167 ± 13 g C·m–2·year–1). As a result of greater aboveground biomass, aboveground C and N storage within shrub islands (3270 ± 466 g C·m–2, 37.9 ± 5.3 g N·m–2) was substantially greater than that within open grassland (241 ± 33 g C·m–2, 6.1 ± 0.8 g N·m–2). No change in soil organic C or total N to 10-cm depth was evident; however, soil CO2 flux was significantly reduced in C. drummondii islands relative to the open grassland. The storage of C in aboveground biomass of C. drummondii represents a significant short-term increase in C storage relative to open grassland. However, potential alterations in belowground processes must be quantified before the long-term net effect of shrub encroachment on C and N pools within this mesic grassland can be determined.Key words: aboveground biomass, Cornus drummondii, net primary productivity, shrub encroachment, tallgrass prairie.

scholarly journals Climate changes during the past 31 years and their contribution to the changes in the productivity of rangeland vegetation in the Inner Mongolian typical steppe

2014 ◽  
Vol 36 (6) ◽  
pp. 519 ◽  
Author(s):  
Xinhong Wu ◽  
Peng Li ◽  
Chao Jiang ◽  
Pengtao Liu ◽  
Jing He ◽  
...  
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Aboveground Biomass ◽  
Human Activities ◽  
Net Primary Productivity ◽  
Annual Production ◽  
Typical Steppe ◽  
The Past ◽  
Grassland Production ◽  
The Impact

The objectives of this study were to explore the impact of climate change and human activities on the annual production of aboveground biomass of vegetation during the past 31 years at a county scale in the typical steppe region of Inner Mongolia. The changes in three banners in the region (Abag Banner, Xilinhaote City, and Xiwuzhumuqin Banner) were analysed. The changes in the annual potential grassland production (net primary productivity) and in the annual production of vegetation, as the sum of aboveground biomass and consumption by livestock, were estimated for each year. A comparison of the changing rates in net primary productivity and aboveground biomass of vegetation over the 31 years was used to distinguish the effects of climate change on grassland production from human activities. The results showed that the climate had become warmer and drier during the past 31 years and thus net primary productivity and annual production of vegetation decreased significantly. Climate change was a major factor for these decreases, while human activities were a minor factor in the decrease of grassland production in Xuwuzhumuqi Banner. The importance of human activities in reducing this decrease in grassland production during the last 31 years is in accordance with the changes in grassland-use policy that has encouraged destocking for grassland restoration in recent years.

scholarly journals The influence of Carboniferous palaeoatmospheres on plant function: an experimental and modelling assessment

1998 ◽  
Vol 353 (1365) ◽  
pp. 131-140 ◽  
Author(s):  
D. J. Beerling ◽  
F. I. Woodward ◽  
M. R. Lomas ◽  
M. A. Wills ◽  
W. P. Quick ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Soil Carbon ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Global Scale ◽  
Carbon Accumulation ◽  
Late Carboniferous ◽  
Atmospheric Composition ◽  
Area Index ◽  
The Impact

Geochemical models of atmospheric evolution predict that during the late Carboniferous, ca . 300 Ma, atmospheric oxygen and carbon dioxide concentrations were 35% and 0.03%, respectively. Both gases compete with each other for ribulose–1,5–bisphosphate carboxylase/oxygenase–the primary C–fixing enzyme in C 3 land plants: and the absolute concentrations and the ratio of the two in the atmosphere have the potential to strongly influence land–plant function. The Carboniferous therefore represents an era of potentially strong feedback between atmospheric composition and plant function. We assessed some implications of this ratio of atmospheric gases on plant function using experimental and modelling approaches. After six weeks growth at 35% O 2 and 0.03% carbon dioxide, no photosynthetic acclimation was observed in the woody species Betula pubescens and Hedera helix relative to those plants grown at 21% O 2 . Leaf photosynthetic rates were 29% lower in the high O 2 environment compared to the controls. A global–scale analysis of the impact of the late Carboniferous climate and atmospheric composition on vegetation function was determined by driving a process–based vegetation–biogeochemistry model with a Carboniferous global palaeoclimate simulated by the Universities Global Atmospheric Modelling Programme General Circulation Model. Global patterns of net primary productivity, leaf area index and soil carbon concentration for the equilibrium model solutions showed generally low values everywhere, compared with the present day, except for a central band in the northern land mass extension of Gondwana, where high values were predicted. The areas of high soil carbon accumulation closely match the known distribution of late Carboniferous coals. Sensitivity analysis with the model indicated that the increase in O 2 concentration from 21% to 35% reduced global net primary productivity by 18.7% or by 6.3 GtC yr –1 . Further work is required to collate and map at the global scale the distribution of vegetation types, and evidence for wildfires, for the late Carboniferous to test our predictions.

scholarly journals Total C and N storage and organic C pools of a Red-Yellow Podzolic under conventional and no tillage at the Atlantic Forest Zone, south-eastern Brazil

Soil Research ◽  
2003 ◽  
Vol 41 (4) ◽  
pp. 717 ◽  
Author(s):  
L. F. C. Leite ◽  
E. S. Mendonça ◽  
P. L. O. A. Machado ◽  
E. S. Matos
Keyword(s):  
Organic Carbon ◽  
Atlantic Forest ◽  
Soil Management ◽  
Microbial Biomass C ◽  
No Tillage ◽  
Forest Zone ◽  
Organic C ◽  
C Stocks ◽  
C And N ◽  
The Impact

A 15-year experiment in a clayey Red-Yellow Podzolic in the tropical highlands of Viçosa, Brazil, was studied in 2000, aiming to evaluate the impact of different management systems (no tillage, disk plowing, heavy scratcher + disk plowing, and heavy scratched) on the total organic carbon (TOC), total nitrogen (TN), and several organic carbon pools. A natural forest, adjacent to the experimental area, was used as reference. The greatest TOC and TN as well as microbial biomass C (CMB), light fraction C (CFL), and labile organic carbon (CL) stocks were observed in the Atlantic Forest, compared with all other systems. The long-term cultivation (±70 years) of this area, prior to the installation of the experiment, has led to soil degradation, slowing the C recovery. No tillage had the higher C and N stocks and greater CL pool at the surface (0–10 cm), indicating improvement in soil nutrient status, although none of the systems presented potential to sequester C-CO2. Sustainable tropical agricultural systems should involve high residue input and conservative soil management in order to act as a C-CO2 sink. The C stocks in the CMB, CFL, and CL compartments were more reduced in relation to the natural vegetation with higher intensity management than the TOC stocks. This result indicates that these C compartments are more sensitive to changes in the soil management.

Assessing the impact of urban land development on net primary productivity in the southeastern United States

2003 ◽  
Vol 86 (3) ◽  
pp. 401-410 ◽  
Author(s):  
Cristina Milesi ◽  
Christopher D. Elvidge ◽  
Ramakrishna R. Nemani ◽  
Steven W. Running
Keyword(s):  
United States ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Southeastern United States ◽  
Land Development ◽  
Urban Land ◽  
The Impact

scholarly journals Effect of elevated tropospheric ozone on soil carbon and nitrogen: A meta-analysis

2022 ◽  
Author(s):  
Enzhu Hu ◽  
Zhimin Ren ◽  
Xiaoke Wang ◽  
Hongxing Zhang ◽  
Weiwei Zhang
Keyword(s):  
Tropospheric Ozone ◽  
Terrestrial Ecosystem ◽  
Soil N ◽  
N Dynamics ◽  
Organic C ◽  
Soil C ◽  
Soil C And N ◽  
C And N ◽  
The Impact ◽  
C And N Dynamics

Abstract Elevated tropospheric ozone concentration ([O3]) may substantially influence the belowground processes of the terrestrial ecosystem. Nevertheless, a comprehensive and quantitative understanding of the responses of soil C and N dynamics to elevated [O3] remains elusive. In this study, the results of 41 peer-reviewed studies were synthesized using meta-analytic techniques, to quantify the impact of O3 on ten variables associated with soil C and N, i.e., total C (TC, including soil organic C), total N (TN), dissolved organic C (DOC), ammonia N (NH4 +), nitrate N (NO3 -), microbial biomass C (MBC) and N (MBN), rates of nitrification (NTF) and denitrification (DNF), as well as C/N ratio. The results depicted that all these variables showed significant changes (P < 0.05) with [O3] increased by 27.6 ± 18.7 nL/L (mean ± SD), including decreases in TC, DOC, TN, NH4 +, MBC, MBN and NTF, and increases in C/N, NO3 - and DNF. The effect sizes of TN, NTF, and DNF were significantly correlated with O3 fumigation level and experimental duration (P < 0.05). Soil pH and climate were essential in analyses of O3 impacts on soil C and N. However, the responses of most variables to elevated [O3] were generally independent of O3 fumigation method, terrestrial ecosystem type, and additional [CO2] exposure. The altered soil C and N dynamics under elevated [O3] may reduce its C sink capacity, and change soil N availability thus impact plant growth and enhance soil N losses.

scholarly journals Do degree and rate of silicate weathering depend on plant productivity?

2020 ◽  
Vol 17 (19) ◽  
pp. 4883-4917 ◽  
Author(s):  
Ralf A. Oeser ◽  
Friedhelm von Blanckenburg
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Nutrient Recycling ◽  
Fold Increase ◽  
Critical Zone ◽  
Mineral Nutrient ◽  
Silicate Weathering ◽  
Weathering Rates ◽  
Novel Strategy ◽  
The Impact

Abstract. Plants and their associated below-ground microbiota possess the tools for rock weathering. Yet the quantitative evaluation of the impact of these biogenic weathering drivers relative to abiogenic parameters, such as the supply of primary minerals, water, and acids, is an open question in Critical Zone research. Here we present a novel strategy to decipher the relative impact of these drivers. We quantified the degree and rate of weathering and compared these to nutrient uptake along the “EarthShape” transect in the Chilean Coastal Cordillera. These sites define a major north–south gradient in precipitation and primary productivity but overlie granitoid rock throughout. We present a dataset of the chemistry of Critical Zone compartments (bedrock, regolith, soil, and vegetation) to quantify the relative loss of soluble elements (the “degree of weathering”) and the inventory of bioavailable elements. We use 87Sr∕86Sr isotope ratios to identify the sources of mineral nutrients to plants. With rates from cosmogenic nuclides and biomass growth we determined fluxes (“weathering rates”), meaning the rate of loss of elements out of the ecosystems, averaged over weathering timescales (millennia), and quantified mineral nutrient recycling between the bulk weathering zone and the bulk vegetation cover. We found that neither the degree of weathering nor the weathering rates increase systematically with precipitation from north to south along the climate and vegetation gradient. Instead, the increase in biomass nutrient demand is accommodated by faster nutrient recycling. In the absence of an increase in weathering rate despite a five-fold increase in precipitation and net primary productivity (NPP), we hypothesize that plant growth might in fact dampen weathering rates. Because plants are thought to be key players in the global silicate weathering–carbon feedback, this hypothesis merits further evaluation.

scholarly journals Comprehensive Assessment of the Effect of Urban Built-Up Land Expansion and Climate Change on Net Primary Productivity

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Pengyan Zhang ◽  
Yanyan Li ◽  
Wenlong Jing ◽  
Dan Yang ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Urban Expansion ◽  
Ecosystem Functions ◽  
Rapid Urbanization ◽  
Important Indicator ◽  
The Impact

Urbanization is causing profound changes in ecosystem functions at local and regional scales. The net primary productivity (NPP) is an important indicator of global change, rapid urbanization and climate change will have a significant impact on NPP, and urban expansion and climate change in different regions have different impacts on NPP, especially in densely populated areas. However, to date, efforts to quantify urban expansion and climate change have been limited, and the impact of long-term continuous changes in NPP has not been well understood. Based on land use data, night light data, NPP data, climate data, and a series of social and economic data, we performed a comprehensive analysis of land use change in terms of type and intensity and explored the pattern of urban expansion and its relationship with NPP and climate change for the period of 2000–2015, taking Zhengzhou, China, as an example. The results show that the major form of land use change was cropland to built-up land during the 2000–2015 period, with a total area of 367.51 km2 converted. The NPP exhibited a generally increasing trend in the study area except for built-up land and water area. The average correlation coefficients between temperature and NPP and precipitation and NPP were 0.267 and 0.020, respectively, indicating that an increase in temperature and precipitation can promote NPP despite significant spatial differences. During the examined period, most expansion areas exhibited an increasing NPP trend, indicating that the influence of urban expansion on NPP is mainly characterized by an evident influence of the expansion area. The study can provide a reference for Zhengzhou and even the world's practical research to improve land use efficiency, increase agricultural productivity and natural carbon sinks, and maintain low-carbon development.

scholarly journals Assessing the Impacts of Urban Expansion on Bundles of Ecosystem Services by Dmsp-Ols Nighttime Light Data

2019 ◽  
Vol 11 (21) ◽  
pp. 5888 ◽  
Author(s):  
Yangyang Gu ◽  
Xuning Qiao ◽  
Mengjia Xu ◽  
Changxin Zou ◽  
Dong Liu ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Primary Productivity ◽  
Crop Production ◽  
Net Primary Productivity ◽  
Urban Expansion ◽  
Forest Recreation ◽  
Ecological Protection ◽  
Expansion Level ◽  
Flood Regulation ◽  
The Impact

Urban expansion poses severe threats to ecosystems. It is therefore important we better understand the impact of different urban expansion level on ecosystems for developing regionally differentiated ecological protection policies. Here, we proposed a conceptual framework to describe the impacts of urbanization on bundles of ecosystem services. Referred to as the concept of land use degree by nighttime light data, we put forward and verified an urban expansion level model. According to this model, study area was divided into a slow increase zone, increase zone, and rapid increase zone. Then, taking Taihu Lake Basin in China as a case, we used Zonal-statistics and Pearson correlation coefficients to reveal the impact in different zones of urban expansion level on multiple ecosystem services: crop production, freshwater supply, aquatic production, net primary productivity, soil conservation, water retention, flood regulation, and forest recreation index. Our results revealed that urban expansion levels significantly impacted all ecosystem services. In either increase zone or rapid increase zone, we found lowered values of crop production, net primary productivity, soil conservation, water retention, and flood regulation, while both aquatic production and forest recreation index increased in all zones from 1990 to 2010. Across the levels of urbanization, urban expansion level was always negatively correlated with provisioning services. This result suggests local governors should improve crop production per unit area and increase the cultivated land area to guarantee food security. In addition, urban expansion level had positive correlations with the trade-offs between flood regulation and forest recreation index, and those among crop production, freshwater supply, and net primary productivity. Therefore, policy-makers should effectively maintain the land use balance among ecological protection, agriculture development, and urban expansion to better coordinate relationships between development and protection. In acquiring quantitative knowledge of how urban expansion level drives ecosystem changes, our findings may help guide future sustainable urban planning with respect to ecosystem services, urban development, and human welfare benefits.

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