It is important to quantitatively analyze the effects of protection of important ecological spaces in China to ensure national ecological security. By considering changes in the ecological land, this study examines the effects of protecting three types of important natural ecological spaces in China from 1980 to 2018. Moreover, considering important ecological spaces and their surroundings yields differences in the effects of protection between internal and external spaces, where this can provide a scientific basis for the categorization and zoning of China’s land. The results show the following: (1) In 2018, the ratio of ecological land to important natural ecological spaces accounted for 92.64%. This land had a good ecological background that reflects the developmental orientation of important ecological spaces. (2) From 1980 to 2018, the area of ecological land in important ecological spaces shrank but the rate of reduction was lower than the national average, which shows the positive effect of regulating construction in natural ecological spaces. The restorative effects of ecological projects to convert farmland into forests and grasslands have been prominent. The expanded ecological land is mainly distributed in areas where such projects have been implemented, and the reduced area is concentrated in grain-producing areas of the Northeast China Plain and agricultural oases of Xinjiang. In the future, the government should focus on strengthening the management and control of these areas. (3) The area ratio of ecological land was the highest in national nature reserves. The rate of reduction in its area was the lowest and the trend of reduction was the smallest in national nature reserves, which reflects differences in the status of ecological protection among different spaces. (4) The ratio of ecological land to important ecological spaces was higher than that in the surrounding external space, and the rate of reduction in it was lower. Thus, the effects of internal and external protection had clear differences in terms of gradient.
Assessing the climate change risk faced by the ecosystems in the arid/humid transition zone (AHTZ) in northern China holds scientific significance to climate change adaptation. We simulated the net primary productivity (NPP) for four representative concentration pathways (RCPs) using an improved Lund-Potsdam-Jena model. Then a method was established based on the NPP to identify the climate change risk level. From the midterm period (2041-2070) to the long-term period (2071-2099), the risks indicated by the negative anomaly and the downward trend of the NPP gradually extended and increased. The higher the scenario emissions, the more serious the risk. In particular, under the RCP8.5 scenario, during 2071-2099, the total risk area would be 81.85%, that of the high-risk area would reach 54.71%. In this high-risk area, the NPP anomaly would reach -96.00±46.95 gC·m-2·a-1, and the rate of change of the NPP would reach -3.56±3.40 gC·m-2·a-1. The eastern plain of the AHTZ and the eastern grasslands of Inner Mongolia are expected to become the main risk concentration areas. Our results indicated that the management of future climate change risks requires the consideration of the synergistic effects of warming and intensified drying on the ecosystem.
The Xinjiang region of China is among the most sensitive regions to global warming. Based on the meteorological and hydrological observation data, the regional wet-to-dry climate regime shifts in Xinjiang were analyzed and the impacts of climatic shift on the eco-hydrological environment of Xinjiang were assessed in this study. The results showed that temperature and precipitation in Xinjiang have increased since the mid-1980s, showing a warming-wetting trend. However, drought frequency and severity significantly increased after 1997. The climate of Xinjiang experienced an obvious shift from a warm-wet to a warm-dry regime in 1997. Since the beginning of the 21st century, extreme temperatures and the number of high temperature days have significantly increased, the start date of high temperature has advanced, and the end date of high temperature has delayed in Xinjiang. In addition, the intensity and frequency of extreme precipitation have significantly increased. Consequently, regional ecology and water resources have been impacted by climatic shift and extreme climate in Xinjiang. In response, satellite-based normalized difference vegetation index showed that, since the 1980s, most regions of Xinjiang experienced a greening trend and vegetation browning after 1997. The soil moisture in Xinjiang has significantly decreased since the late 1990s, resulting in adverse ecological effects. Moreover, the response of river runoff to climatic shift is complex and controlled by the proportion of snowmelt to the runoff. Runoff originating from the Tianshan Mountains showed a positive response to the regional wet-to-dry shift, whereas that originating from the Kunlun Mountains showed no obvious response. Both climatic shift and increased climate extremes in Xinjiang have led to intensification of drought and aggravation of instability of water circulation systems and ecosystem. This study provides a scientific basis to meet the challenges of water resource utilization and ecological risk management in the Xinjiang region of China.
Climate change (CC) and human activities (HA) are the main reasons for the restoration/degradation of the Qinghai-Tibet Plateau (QTP) grassland. Many related studies have been conducted thus far, but the impact mechanism of CC coupled with HA on QTP remains unclear. We summarized the two main coupling factors in recent years (specifically, in the past five years) and obtained the following conclusions. (1) CC and HA have positive and negative effects on the QTP grassland ecosystem. CC primarily affects grassland ecology through temperature, humidification, and extreme climate, and HA mainly affects ecosystems through primary, secondary, and tertiary industries and restoration measures. (2) CC coupled with HA affects soil, plants, animals, and fungi/microbes. CC makes the snow line rise by increasing the temperature, which expands the zone for HA. CC also restricts HA through hydrological changes, extreme climate, and outbreak of pikas and pests. Simultaneously, measures are implemented through HA to control and adapt to CC. Hence, the grassland ecosystem is comprehensively influenced by CC and HA. (3) The grassland ecosystem dynamically adapts to the disturbance caused by CC and HA by changing its physiological characteristics, distribution range, diet structure, community structure, and physical state. Simultaneously, it responds to environmental changes through desertification, poisonous weeds, rodent outbreak, release of harmful gases, and other means. This work can be used as a reference for the sustainable development of the QTP grassland.
Global large-scale urbanization and climate change have become indisputable scientific facts yet are unresolved issues, and are a common concern for mankind. The relationship between these two topics is unclear and it is not known how to deal appropriately at the scientific level with climate change in the process of urbanization. Further exploration of the science, management and practice, are needed to achieve global and regional sustainable development. This paper first considers the basic facts concerning mass urbanization and climate change and summarizes the interactions and possible mechanisms of urbanization and climate change. Urbanization leads to the heat island effect, an uneven distribution of precipitation and extreme weather, together with a local-regional-global multi-scale superposition effect, which aggravates the consequences of global climate change. The impact of climate change on urbanization is mainly manifested in aspects such as changes of energy consumption, mortality, and the spread of infectious diseases, sea level rise, extreme weather damage to infrastructure, and water shortages. This paper also briefly reviews relevant international research programs and action coalitions and puts forward an analysis framework of multi-dimensional sustainable urbanization which can adapt to and mitigate climate change, from the perspective of the four key dimensions—population, land use, economy, and society. It is imperative that we strengthen the interdisciplinary activities involving the natural and social sciences, take urbanization and other human activities into consideration of the land - atmosphere system, and explore the human-land-atmosphere coupling process. The adaptation and mitigation from the perspective of human activities, as represented by urbanization, might be the most critical and realistic way to deal with climate change.
Rural spatial governance has become an important part of the spatial governance system under the unified management of urban and rural spaces. In-depth theoretical and practical research on rural spatial governance in terms of promoting national spatial planning can help improve the planning and regulation system of rural space. Beginning with a description of rural spatial governance, this paper constructs a theoretical analysis framework of rural spatial governance based on the comprehensive perspective of spatial governance. The study also discusses the internal processes and feasible paths of rural spatial governance in territorial spatial planning and outlines the theoretical and practical research for enhancing rural spatial governance. The conclusions are as follows: (1) Rural spatial governance starts with the coordination theory of human-land relationships in the rural regional system. Through planning and negotiation, governance has effective regulation of rural space and allocates spatial rights in an orderly manner. Rural spatial governance highlights the comprehensive governance processes that combine “top-down” and “bottom-up” participation by multiple subjects. (2) Through the “action-efficiency-target” system, the comprehensive governance analysis framework of “matter-organization-ownership” in rural space provides an effective scheme for constructing rural spatial governance. Rural spatial governance is characterized by both rigidity and flexibility, the interaction between physical space and spatial relationships, and the superposition of spatial ownership and spatial organization. (3) The rural spatial governance features of interconnecting various scales (regional-village-plot) are conducive to improving the rural spatial governance system. (4) The governance means, participation modes, and value-sharing mechanisms of rural spatial governance help enrich the territorial spatial planning system, promote the integration of multiple regulations, refine the regulation of land use, and ensure good rural governance and ecological governance.
In the past 40 years, cultivated land has faced the continued anthropogenic interference, which has become a significant issue for cultivated land preservation during rapid urbanization. The purpose of this research was to reveal the spatio-temporal evolutionary characteristics of cultivated land and the correlation between rural population variation and farmland change in China. Fifty county-level administrative units in Zhejiang Province were selected as the study area wherein spatio-temporal evolution comparative analysis for every 5 years from 2000 to 2015 was conducted. This study used the pool method to estimate the impacts of the rural population variation, average slope, average elevation, rural residential disposable income, primary industry proportion, and road density on farmland utilization efficiency from the spatial perspective, which is represented by landscape metrics including the mean patch size, edge density, area weighted mean shape index, and area weighted mean patch fractal dimension. This study showed that the cultivated land landscape index continued to rise after 2000 and then started decreasing after 2010, indicating a reduction in human interference after 2010. The spatial variation of rural population of all county-level administrative units decreased from 2000 to 2010, and 62% of them began to increase after 2010. The regression analysis results showed that the spatial variation of rural population was significantly and negatively correlated with the cultivated land landscape while the rural residential disposable income, average slope and primary industry proportion were all significantly and positively related to the cultivated land landscape index. The results implied that the loss of the agricultural labor force and the difficulty of sloping farmlands adapting to mechanized farming were unconducive to farmland utilization efficiency improvement, and the increase in nonagricultural activities in rural areas would increase the difficulty of cultivated land preservation. Our analysis suggests that local governments should improve the production efficiency of fragmented land or strengthen the construction control of housing and facilities in rural areas according to their regional urbanization development situation.
As one of the most critical impact factors of global change, historical land-use change is an indispensable input in climate and environment simulations. To better understand the cropland change in the Guanzhong area, gazetteers, statistics, and survey data were collected as data sources. Methods of registered tax-paying cropland data collection, selection of time points, and data interpolation and calibration were used to reconstruct changes in the cropland area. The cropland area data at the county level were allocated to 1 km×1 km grid cells. The total cropland area in the Guanzhong area was influenced by changes in population, wars, natural disasters, and land-use types, and it fluctuated from 1650 to 2016. From 1780 to 1830, the cropland expanded in the northern and western parts of Guanzhong area, and the cropland in the north of Qinling Mountains increased slightly. The spatial pattern of cropland reached its maximum range in 1980, and the cropland area declined in the whole study area, especially in the cities of Xi’an and Xianyang in 2016. The comparison between HYDE 3.2 and the data obtained in this study showed that the grid cells of HYDE 3.2 exhibit lower values of cropland area fractions in the Guanzhong Basin and higher values in high-altitude areas around the Guanzhong Basin as compared to those in this study.
