Quantitative Assessment of the Impact of Human Activities on Terrestrial Net Primary Productivity in the Yangtze River Delta

Exploring the relationships between human consumption and environmental pressure: A case study of the Yangtze river economic zone in China

It is crucial to decouple and coordinate human consumption and its environmental pressure for achieving sustainable development. As an important aspect of United Nations Sustainable Development Goal (SDG12), sustainability on material consuming is still in its early stages of research. To address the research gap in sustainable consumption of vegetation net primary productivity (NPP), this study analyzed the spatio-temporal dynamics of human consumption and environmental pressure in the Yangtze River Economic Zone (YREZ) using consumption-based HANPP (cHANPP) and Human Appropriation of Net Primary Production (HANPP) as indicators. Later, we measured their decoupling relationship using Tapio decoupling approach. We found that distribution of HANPP and cHANPP were regionally separated, with the former mainly concentrated in the middle and upper reaches provinces, while the latter concentrated in the lower reach provinces. From 2004 to 2019, the relationship between HANPP and cHANPP changed from strong negative decoupling to weak decoupling in the YREZ. Furthermore, the relationship was differed among different regions. As a whole, developing regions showed a weak decoupling state, experiencing an increase in environmental pressure (i.e., HANPP) alongside increased human consumption (i.e., cHANPP). In contrast, developed regions showed a strong decoupling state, experiencing a decrease in environmental pressure (i.e., HANPP) alongside increased human consumption (i.e., cHANPP). Our study highlights that different countermeasures should be formulated by regions according to their own situation to realize sustainable regional development.

Assessing the Effects of Human Activities on Terrestrial Net Primary Productivity of Grasslands in Typical Ecologically Fragile Areas

Global enhanced human activities have deeply influenced grassland ecosystems. Quantifying the impact of human activities on grasslands is crucial to understanding the grassland dynamic change mechanism, such as grassland degradation, and to establishing ecosystem protection measures. In this study, potential net primary productivity (PNPP), actual NPP (ANPP), and the forage harvest NPP (HNPP) were employed to establish the human activities index (HAI) to reveal the spatiotemporal changes of the effects of human activities on grassland ecosystems in eastern Inner Mongolia from 2000 to 2017, and to further explore the relationship between human activities and grassland degradation. The results showed that the total average PNPP, ANPP, and HNPP of grasslands in eastern Inner Mongolia were 187.2 Tg C yr^-1, 152.3 Tg C yr^-1, and 8.9 Tg C yr^-1, respectively, during the period of 2000 to 2017. The HAI exhibited a clear decreasing trend during the study period, with annual mean values ranging from 0.75 to 0.47, which indicates that the NPP loss induced by human activities is weakening, and this trend is dominated by the difference between potential NPP and actual NPP. About 42.4% of the study area was non-degraded grassland, and the declining grassland degradation index (GDI) indicated that the degradation grade in eastern Inner Mongolia improved from moderate to light degradation. A positive relationship was found between HAI and GDI. This relationship was more significant in Xilingol League, which is a typical ecologically fragile area, than that in Xing'an League and Hulunbuir City.

Assessing the Net Primary Productivity Dynamics of the Desert Steppe in Northern China during the Past 20 Years and Its Response to Climate Change

The net primary productivity (NPP) dynamics in arid and semi-arid ecosystems are critical for regional carbon management. Our study applied a light-utilization-efficiency model (CASA: Carnegie–Ames–Stanford Approach) to evaluate the vegetation NPP dynamics of a desert steppe in northern China over the past 20 years, and its response to climate change. Our results show that the annual average NPP of the desert steppe was 132 g C m−2 y−1, of which the grass- and shrub-dominated biome values were 142 and 91 g C m−2 y−1, respectively. The average change rate of NPP was 1.13 g C m−2 y−1, and in the grassland biome 1.31 g C m−2 y−1, a value which was significantly higher than that in shrubland, at 0.84 g C m−2 y−1. The precipitation and temperature at different time scales in the desert steppe showed a slow upward trend, and the degree of aridity tended to weaken. The correlation analysis shows that NPP changes were significantly positively and negatively correlated with precipitation and temperature, respectively. In terms of temperature, 43% of the area was significantly correlated during the growing season, which decreased to 12% on the annual scale. In 31% of the changed areas, the average NPP was 148.1 g C m−2 y−1, which was higher than the remaining significant areas. This suggests that higher NPP levels help to attenuate the negative effects of high temperature during the growing season on plant productivity in the desert steppe. This improves the understanding of the carbon cycle mechanism of arid and semi-arid ecosystems, which is beneficial to improving sustainable grassland development strategies.

The Impacts of Calamity Logging on the Sustainable Development of Spruce Fuel Biomass Prices and Spruce Pulp Prices in the Czech Republic

Currently, due to the calamity of unplanned harvesting, the amount of biomass from wood products has increased. Forests occupy 33.7% of the total area of the Czech Republic; therefore, wood and non-wood forest products are important renewables for the country. Wood biomass consists mainly of branches and bark that are not used in the wood or furniture industry. However, it can be used in bioenergy, including wood processing for fuel. As spruce production in the Czech Republic increased from the planned 15.5 million to almost 36.8 million trees in 2020, the price of wood biomass can be expected to be affected. This study aims to develop a predictive model for estimating the decline in the price of wood biomass for wood processors, such as firewood or sawdust producers, as well as for the paper industry. Wood biomass prices are falling with each additional million m3 of spruce wood harvested, as is the decline in wood pulp, which is intended for the paper and packaging industries. The proposed predictive model based on linear regressions should determine how the price of wood biomass will decrease with each additional million harvested spruce trees in the Czech Republic. This tool will be used for practical use in the forestry and wood industry. The linear regression model is suitable for practical forestry use due to its simplicity and high informative value. The aim of the research is to model the dependence of the prices of firewood in the form of wood briquettes and pellets for domestic and industrial processing, as well as the prices of wood pulp on the volume of unplanned logging. It is a guide for the practice of how to use excess spruce wood from unplanned mining in the field of alternative processing with a sustainable aspect for households or heat production for households. The intention is to carry out modelling in such a way that it does not include prices of higher quality wood assortments, which are intended for the woodworking industry.