scholarly journals Spatiotemporal Evolution of the Carbon Fluxes from Bamboo Forests and their Response to Climate Change Based on a BEPS Model in China

2022 ◽  
Vol 14 (2) ◽  
pp. 366
Author(s):  
Fangfang Kang ◽  
Xuejian Li ◽  
Huaqiang Du ◽  
Fangjie Mao ◽  
Guomo Zhou ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Climatic Factors ◽  
Carbon Fluxes ◽  
Negative Effects ◽  
Spatiotemporal Evolution ◽  
Positive Effects ◽  
The North ◽  
Boreal Ecosystem ◽  
Beps Model

Carbon flux is the main basis for judging the carbon source/sink of forest ecosystems. Bamboo forests have gained much attention because of their high carbon sequestration capacity. In this study, we used a boreal ecosystem productivity simulator (BEPS) model to simulate the gross primary productivity (GPP) and net primary productivity (NPP) of bamboo forests in China during 2001–2018, and then explored the spatiotemporal evolution of the carbon fluxes and their response to climatic factors. The results showed that: (1) The simulated and observed GPP values exhibited a good correlation with the determination coefficient (R2), root mean square error (RMSE), and absolute bias (aBIAS) of 0.58, 1.43 g C m−2 day−1, and 1.21 g C m−2 day−1, respectively. (2) During 2001–2018, GPP and NPP showed fluctuating increasing trends with growth rates of 5.20 g C m−2 yr−1 and 3.88 g C m−2 yr−1, respectively. The spatial distribution characteristics of GPP and NPP were stronger in the south and east than in the north and west. Additionally, the trend slope results showed that GPP and NPP mainly increased, and approximately 30% of the area showed a significant increasing trend. (3) Our study showed that more than half of the area exhibited the fact that the influence of the average annual precipitation had positive effects on GPP and NPP, while the average annual minimum and maximum temperatures had negative effects on GPP and NPP. On a monthly scale, our study also demonstrated that the influence of precipitation on GPP and NPP was higher than that of the influence of temperature on them.

scholarly journals Spatio-Temporal Changes of Vegetation Net Primary Productivity and Its Driving Factors on the Qinghai-Tibetan Plateau from 2001 to 2017

2021 ◽  
Vol 13 (8) ◽  
pp. 1566
Author(s):  
Yin Zhang ◽  
Qingwu Hu ◽  
Fengli Zou
Keyword(s):  
Tibetan Plateau ◽  
Primary Productivity ◽  
Human Activities ◽  
Net Primary Productivity ◽  
Climatic Factors ◽  
Correlation Coefficients ◽  
Google Earth ◽  
Computing Platform ◽  
Positive Effects ◽  
Spatio Temporal

The Qinghai-Tibetan Plateau (QTP) is the highest plateau in the world. Under the background of global change, it is of unique significance to study the net primary productivity (NPP) of vegetation on the QTP. Based on the Google Earth Engine (GEE) cloud computing platform, the spatio-temporal variation characteristics of the NPP on the QTP from 2001 to 2017 were studied, and the impacts of climate change, elevation and human activity on the NPP in the QTP were discussed. The mean and trend of NPP over the QTP were “high in the southeast and low in the northwest” during 2001–2017. The trend of NPP was mostly between 0 gC·m−2·yr−1 and 20 gC·m−2·yr−1 (regional proportion: 80.3%), and the coefficient of variation (CV) of NPP was mainly below 0.16 (regional proportion: 89.7%). Therefore, NPP was relatively stable in most regions of the QTP. Among the correlation coefficients between NPP and temperature, precipitation and human activities, the positive correlation accounted for 81.1%, 48.6% and 56.5% of the QTP area, respectively. Among the two climatic factors, the influence of temperature on NPP was greater than that of precipitation. The change of human activities and the high temperature at low altitude had positive effects on the increase of NPP.

scholarly journals The Role of Forests in Climate Change Regarding Carbon, Nitrogen, and Water: A Case Study of Pinus densiflora

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3050
Author(s):  
Dong Kook Woo ◽  
Wonseok Do
Keyword(s):  
Climate Change ◽  
South Korea ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Pinus Densiflora ◽  
Biogeochemical Model ◽  
Negative Effects ◽  
Rcp Scenarios ◽  
Positive Effects ◽  
Use Efficiency

We examined the influence of climate change on the dynamics of Pinus densiflora, the most dominant tree species in South Korea, to explore its potential for climate change mitigation. We considered changes in precipitation, temperature, and CO2 under four representative concentration pathway (RCP) scenarios separately and in combination to evaluate the responses of Pinus densiflora to climate change. A well-tested ecohydrological and biogeochemical model, ecosys, was used to study the Gwangneung Experimental Forest in South Korea. Results showed that the positive effects of CO2 fertilizer on gross primary productivity (GPP) and net primary productivity (NPP) outweighed the negative effects caused by changes in precipitation and temperature. In particular, NPP improvements of 3.79%, 13.44%, 18.26%, and 28.91% were modeled under RCP values of 2.6, 4.5, 6.5, and 8.5, respectively, compared to the baseline. We found that nitrogen leaching and N2O flux reduced as climate change become severe due to increases in nutrient uptake, leading to reduced soil nitrogen losses. Although evapotranspiration increased as the intensity of climate change increased, reductions in the stomatal opening improved the water use efficiency of Pinus densiflora. These results indicated that Pinus densiflora could serve as an environmentally friendly option to minimize climate change consequences.

scholarly journals Effects of climatic factors on the net primary productivity in the source region of Yangtze River, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Yuan ◽  
Yongqiang Wang ◽  
Jijun Xu ◽  
Zhiguang Wu
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Yangtze River ◽  
Net Primary Productivity ◽  
Climatic Factors ◽  
Source Region ◽  
Primary Reason ◽  
Vegetation Types ◽  
Temperature And Precipitation ◽  
Increasing Trend

AbstractThe ecosystem of the Source Region of Yangtze River (SRYR) is highly susceptible to climate change. In this study, the spatial–temporal variation of NPP from 2000 to 2014 was analyzed, using outputs of Carnegie–Ames–Stanford Approach model. Then the correlation characteristics of NPP and climatic factors were evaluated. The results indicate that: (1) The average NPP in the SRYR is 100.0 gC/m2 from 2000 to 2014, and it shows an increasing trend from northwest to southeast. The responses of NPP to altitude varied among the regions with the altitude below 3500 m, between 3500 to 4500 m and above 4500 m, which could be attributed to the altitude associated variations of climatic factors and vegetation types; (2) The total NPP of SRYR increased by 0.18 TgC per year in the context of the warmer and wetter climate during 2000–2014. The NPP was significantly and positively correlated with annual temperature and precipitation at interannual time scales. Temperature in February, March, May and September make greater contribution to NPP than that in other months. And precipitation in July played a more crucial role in influencing NPP than that in other months; (3) Climatic factors caused the NPP to increase in most of the SRYR. Impacts of human activities were concentrated mainly in downstream region and is the primary reason for declines in NPP.

scholarly journals Monitoring Phenology in the Temperate Grasslands of China from 1982 to 2015 and Its Relation to Net Primary Productivity

2019 ◽  
Vol 12 (1) ◽  
pp. 12
Author(s):  
Chaobin Zhang ◽  
Ying Zhang ◽  
Zhaoqi Wang ◽  
Jianlong Li ◽  
Inakwu Odeh
Keyword(s):  
Primary Productivity ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Net Primary Productivity ◽  
Meteorological Data ◽  
Temperate Grasslands ◽  
The North ◽  
Phenological Changes ◽  
Grass Growth ◽  
Global Inventory

Both vegetation phenology and net primary productivity (NPP) are crucial topics under the background of global change, but the relationships between them are far from clear. In this study, we quantified the spatial-temporal vegetation start (SOS), end (EOS), and length (LOS) of the growing season and NPP for the temperate grasslands of China based on a 34-year time-series (1982–2015) normalized difference vegetation index (NDVI) derived from global inventory modeling and mapping studies (GIMMS) and meteorological data. Then, we demonstrated the relationships between NPP and phenology dynamics. The results showed that more than half of the grasslands experienced significant changes in their phenology and NPP. The rates of their changes exhibited spatial heterogeneity, but their phenological changes could be roughly divided into three different clustered trend regions, while NPP presented a polarized pattern that increased in the south and decreased in the north. Different trend zones’ analyses revealed that phenology trends accelerated after 1997, which was a turning point. Prolonged LOS did not necessarily increase the current year’s NPP. SOS correlated with the NPP most closely during the same year compared to EOS and LOS. Delayed SOS contributed to increasing the summer NPP, and vice versa. Thus, SOS could be a predictor for current year grass growth. In view of this result, we suggest that future studies should further explore the mechanisms of SOS and plant growth.

scholarly journals Climate and competition influence sockeye salmon population dynamics across the Northeast Pacific Ocean

2020 ◽  
Vol 77 (6) ◽  
pp. 943-949 ◽  
Author(s):  
Brendan Connors ◽  
Michael J. Malick ◽  
Gregory T. Ruggerone ◽  
Pete Rand ◽  
Milo Adkison ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Large Scale ◽  
Pacific Salmon ◽  
Spatial Scales ◽  
Interspecific Interactions ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Negative Effects ◽  
Positive Effects ◽  
The North

Pacific salmon productivity is influenced by ocean conditions and interspecific interactions, yet their combined effects are poorly understood. Using data from 47 North American sockeye salmon (Oncorhynchus nerka) populations, we present evidence that the magnitude and direction of climate and competition effects vary over large spatial scales. In the south, a warm ocean and abundant salmon competitors combined to strongly reduce sockeye productivity, whereas in the north, a warm ocean substantially increased productivity and offset the negative effects of competition at sea. From 2005 to 2015, the approximately 82 million adult pink salmon (Oncorhynchus gorbuscha) produced annually from hatcheries were estimated to have reduced the productivity of southern sockeye salmon by ∼15%, on average. In contrast, for sockeye at the northwestern end of their range, the same level of hatchery production was predicted to have reduced the positive effects of a warming ocean by ∼50% (from a ∼10% to a ∼5% increase in productivity, on average). These findings reveal spatially dependent effects of climate and competition on sockeye productivity and highlight the need for international discussions about large-scale hatchery production.

Climate Variability in Tallgrass Prairie at Multiple Timescales: Konza Prairie Biological Station

2003 ◽  
Author(s):  
Douglas G. Goodin ◽  
Philip A. Fay
Keyword(s):  
Climate Variability ◽  
Tallgrass Prairie ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Konza Prairie ◽  
Central Plains ◽  
Atmospheric Processes ◽  
Biological Station ◽  
The North ◽  
Temperature And Precipitation

Climate is a fundamental driver of ecosystem structure and function (Prentice et al. 1992). Historically, North American grassland and forest biomes have fluctuated across the landscape in step with century- to millennialscale climate variability (Axelrod 1985; Ritchie 1986). Climate variability of at decadal scale, such as the severe drought of the 1930s in the Central Plains of North America, caused major shifts in grassland plant community composition (Weaver 1954, 1968). However, on a year-to-year basis, climate variability is more likely to affect net primary productivity (NPP; Briggs and Knapp 1995; Knapp et al. 1998; Briggs and Knapp 2001). This is especially true for grasslands, which have recently been shown to display greater variability in net primary production in response to climate variability than forest, desert, or arctic/alpine systems (Knapp and Smith 2001). Although the basic relationships among interannual variability in rainfall, temperature, and grassland NPP have been well studied (Sala et al. 1988; Knapp et al. 1998; Alward et al. 1999), the linkages to major causes of climate variability at quasi-quintennial (~5 years) or interdecadal (~10 year) timescales in the North American continental interior, such as solar activity cycles, the El Niño–Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), and the North Pacific Index (NP), are less well understood. In this chapter, we will examine how interannual, quasi-quintennial, and interdecadal variation in annual precipitation and mean annual temperature at a tallgrass prairie site (Konza Prairie Biological Station) may be related to indexes of solar activity, ENSO, NAO, and NP, and in turn how these indexes may be related to aboveground net primary productivity (ANPP). Specifically, we present (1) period-spectrum analyses to characterize the predominant timescales of temperature and precipitation variability at Konza Prairie, (2) correlation analyses of quantitative indexes of the major atmospheric processes with Konza temperature and precipitation records, and (3) the implications of variation in major atmospheric processes for seasonal and interannual patterns of ANPP. The Konza Prairie Biological Station (KNZ), which lies in the Flint Hills (39º05' N, 96º35' W), is a 1.6-million-ha region spanning eastern Kansas from the Nebraska border to northeastern Oklahoma (figure 20.1). This region is the largest remaining tract of unbroken tallgrass prairie in North America (Samson and Knopf 1994) and falls in the more mesic eastern portion of the Central Plains grasslands.

scholarly journals The up-scaling of ecosystem functions in a heterogeneous world

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Andrew M. Lohrer ◽  
Simon F. Thrush ◽  
Judi E. Hewitt ◽  
Casper Kraan
Keyword(s):  
Primary Productivity ◽  
Ecosystem Functioning ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Marine Ecosystem ◽  
Ecosystem Functions ◽  
Small Scale ◽  
Biodiversity Crisis ◽  
Positive Effects ◽  
Marine Habitats

Abstract Earth is in the midst of a biodiversity crisis that is impacting the functioning of ecosystems and the delivery of valued goods and services. However, the implications of large scale species losses are often inferred from small scale ecosystem functioning experiments with little knowledge of how the dominant drivers of functioning shift across scales. Here, by integrating observational and manipulative experimental field data, we reveal scale-dependent influences on primary productivity in shallow marine habitats, thus demonstrating the scalability of complex ecological relationships contributing to coastal marine ecosystem functioning. Positive effects of key consumers (burrowing urchins, Echinocardium cordatum) on seafloor net primary productivity (NPP) elucidated by short-term, single-site experiments persisted across multiple sites and years. Additional experimentation illustrated how these effects amplified over time, resulting in greater primary producer biomass (sediment chlorophyll a content) in the longer term, depending on climatic context and habitat factors affecting the strengths of mutually reinforcing feedbacks. The remarkable coherence of results from small and large scales is evidence of real-world ecosystem function scalability and ecological self-organisation. This discovery provides greater insights into the range of responses to broad-scale anthropogenic stressors in naturally heterogeneous environmental settings.

The response of net primary productivity of two different vegetation types to climatic factors and root turnover analysis on the Qinghai-Tibet Plateau

2019 ◽  
Vol 39 (14) ◽  
Author(s):  
戴黎聪 DAI Licong ◽  
郭小伟 GUO Xiaowei ◽  
张法伟 ZHANG Fawei ◽  
柯浔 KE Xun ◽  
曹莹芳 CAO Yingfang ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Climatic Factors ◽  
Tibet Plateau ◽  
Root Turnover ◽  
Vegetation Types ◽  
Qinghai Tibet Plateau

scholarly journals NAFTA, Social Unionism, and Labour Movement Power in Canada and the United States

2005 ◽  
Vol 49 (4) ◽  
pp. 657-695 ◽  
Author(s):  
Ian Robinson
Keyword(s):  
United States ◽  
Trade Agreement ◽  
The United States ◽  
Negative Effects ◽  
Labour Movement ◽  
Positive Effects ◽  
The North ◽  
Long Run ◽  
Short Run ◽  
Negative Impacts

This paper considers how the North American Free Trade Agreement (NAFTA) is likely to affect labour movement power in Canada and the United States. The paper is divided into four parts. It first defines the concept of « labour movement power », breaking it down into its component parts. It next considers why we should care about what happens to labour movement power. It then outlines the principal negative and positive effects that the NAFTA is likely to have on labour movement power. Attention is also given to the beneficial consequences that the fight against the NAFTA has already had for the labour movement. It is argued that the NAFTA 's negative impacts are likely to outweight its positive ones in the short run and that the positive effects could substantially outweight its negative effects over the medium to long run. Whether it does will depend upon choices made in the next few years by labour movement leaders and activists.

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