Correlated increases in population and demand for food over recent decades have caused remarkable changes in cropland area globally. Utilizing the latest data product provided by the European Space Agency (ESA), this paper analyzes annual trends and spatiotemporal variations in cropland area and discusses cropland conversion, losses, and increases globally between 1992 and 2015 at a 300 m resolution. The results show that the global area of cropland increased rapidly between 1992 and 2004, more slowly between 2004 and 2012, and began to decrease gradually since 2012. First, an increasing trend in cropland area has been maintained solely in Africa; all other regions are characterized by decreasing trends in later periods despite different transition points and change rates. A reduction in cropland area frequently emerged earlier in high-income countries. Second, increase rates in cropland area have largely decreased in recent years while the overall rate of loss has remained almost the same. Hotspot areas of global cropland increases are mainly concentrated around the edge of the Amazon forest, Eurasian Steppe, and Sahara Desert. These hotspot areas of global cropland loss shifted from Europe to Asia while built-up areas have expanded at the expense of cropland.
A combination of rapid industrialization, economic development and urbanization has caused a series of issues such as resource shortages, ecosystem destruction, environmental pollution and tension between human needs and land conservation. In order to promote balanced development of human, resources, ecosystems, the environment, and the economy and society, it is vital to conceptualize ecological spaces, production spaces and living spaces. Previous studies of ecological-production-living spaces focused mainly on urban and rural areas; few studies have examined mountainous areas. The Taihang Mountains, a key area between the North China Plain and Beijing-Tianjin-Hebei area providing ecological shelter and the safeguarding of crucial water sources, suffer from increasing problems of fragile environment, inappropriate land use and tensions in the human-land relationship. However, studies of the ecological, production, and living spaces in the Taihang Mountains are still lacking. Therefore, this study, based on the concept of ecological-production-living spaces and using data from multiple sources, took the Taihang Mountains as the study area to build a functional land classification system for ecological-production-living spaces. After the classification system was in place, spatial distribution maps for ecological, production and living spaces were delineated. This space mapping not only characterized the present land use situation, but also established a foundation for future land use optimization. Results showed that the area of ecological space was 78,440 km2, production space 51,861 km2 and living space 6,646 km2, accounting for 57.28%, 37.87% and 4.85% of the total area, respectively. Ecological space takes up the most area and is composed mainly of forests and grasslands. Additionally, most of the ecological space is located in higher elevation mountainous areas, and plays an important role in regulating and maintaining ecological security. Production space, mostly farmlands sustaining livelihoods inside and outside the region, is largely situated in lower elevation plains and hilly areas, as well as in low-lying mountainous basins. Living space has the smallest area and is concentrated mainly in regions with relatively flat terrain and convenient transportation for human settlements.
This paper examines the spatial characteristics of farmer/household behaviors in regional rice cropping systems (RCS), and the results provide necessary information for developing strategies that will maintain regional food security. Through field study and statistical analysis based on 402 households questionnaires finished in 2014-2015 in the Poyang Lake Region (PLR) of China, we arrived at two main conclusions. First, single- and double cropping rice were found across the study area, but showed a general distribution trend, with double cropping rice in the southeast part (especially in Jinxian county) and single cropping rice in the northwest (particularly in De’an county). Second, the household decisions concerning RCS varied in different parts of the PLR, but double cropping was the dominant type, with about 63.57% of the respondent households in the PLR cultivating double cropping rice. However, the multiple-cropping index of paddy rice was only 1.55. About 3% of interviewed households had altered their RCS during this period. Based on these findings, the local governments should guide farmers’ paddy field cultivation behaviors by increasing the comparative efficiency of rice production, promoting appropriate scale operations and land conversion, as well as optimizing rice growing conditions to improve the multiple cropping index and enhance food provision. Finally, land-use efficiency and more sustainable use of land resources should be improved.
Based on the cost-income data of agricultural products and relevant statistical data, taking major grain crops and economic crops in the process of cultivated land use as study cases, we studied characteristics of the temporal variation of cultivated land use intensity and its composition in Shandong Province from 1980 to 2015, and then analyzed its main driving factors. The results showed that: (1) The total intensity of major crops in Shandong Province showed a rising trend from 919.73 Yuan ha-1 in 1980 to 3285.06 Yuan ha-1 in 2015, and the average annual intensity of economic crops was higher than that of grain crops. The labor cost and material cost of major crops both showed an increasing trend, but the material input was much higher than labor input for grain crops, while the labor input was much higher than material input for economic crops. (2) The labor intensity of major crops in Shandong Province showed a decreasing trend from 501.75 man-day ha-1 in 1980 to 161.93 man-day ha-1 in 2015. The labor intensity of grain crops was lower than that of economic crops and its decline rate was fast. On the contrary, the capital intensity showed an increasing trend from 518.33 Yuan ha-1 in 1980 to 1159.95 Yuan ha-1 in 2015. In the internal composition of capital intensity, the proportion of yield-increasing inputs such as seed, farmyard manure, fertilizer, pesticide and drainage and irrigation decreased gradually, while the proportion of labor-saving inputs such as agricultural machinery increased significantly. (3) The cultivated land use intensity in Shandong Province had significant negative correlations with the amount of agricultural labor and cultivated land area per capita. The primary direct driving factor was the net income per unit cost of major crops, but the time response lagged by 1-3 years. The main indirect driving factor was the reform of agricultural policy.
In order to explore the relationship between urban construction land and economic development, this paper uses a decoupling model to analyze the decoupling relationship between expansion of urban construction land and economic growth in Jilin Province. The results show that from 2000 to 2015, the decoupling of urban construction land expansion and economic growth in Jilin province tended to be reasonable. The paper divides urban decoupling into three categories. The first type consists of ideal cities, including Liaoyuan and Baishan. The second type includes basic ideal cities like Changchun, Tonghua, Songyuan, Baicheng, and Yanbian. The third type consists of non-ideal cities, including Jilin and Siping. This paper puts forward relevant measures to promote the further decoupling of construction land expansion and economic growth in order to realize the sustainable use of land resources.
With the rapid development of the society and the economy, people are paying more attention to the value of natural resources and the benefits of the ecological environment. Evaluating the value of eco-assets has become a focus of concern. Quantitative remote sensing measurements, land data and other auxiliary data were used to measure the eco-assets in 46 regions of the Wanjiang Demonstration Area from 1990 to 2013. This paper analyzes temporal and spatial variations of eco-assets’ distribution, composition, change patterns and the factors driving variations. The results show that the distribution of eco-assets in the regions is very uneven, the central region has higher ecological assets than other regions, and it declined first and then rose during the period 1990-2013. The total amount of eco-assets increased by 3.05%. The change in the amount of ecological assets was not large, but it is important that the amount of assets was basically stable, and increases in the proportion of degraded areas was small. Grassland and water body eco-assets decreased by 11.19% and 0.66%, respectively, and that of cultivated land decreased by 15.54%, but forest land increased by 6.42%. As for the change pattern of ecological assets, the per capita assets of Hefei had the largest reduction, and those of Xuancheng the second largest. The spatial and temporal changes of ecological assets in the Wanjiang Demonstration Area include natural factors and human factors. The government's macro-control and economic policies are the main driving factors for the spatial and temporal changes of the ecological assets pattern.
The aim of this study is to find an optimal design for a distributed hybrid renewable energy system (HRES) for a residential house in the UK. The hybrid system, which consists of wind turbines, PV arrays, a biodiesel generator, batteries and converters, is designed to meet the known dynamic electrical load of the house and make use of renewable energy resources available locally. Hybrid Optimization Model for Electric Renewables (HOMER) software is used for this study. Different combinations of wind turbines, PV arrays, a biodiesel generator and batteries are evaluated and compared using the NPC (Net Present Cost) method to find the optimal solutions. The HRES is modeled, simulated and optimized using HOMER. The results showed that the wind-biodiesel engine-battery system was the best with the lowest NPC (USD 60254) and the lowest COE (Cost of Energy, USD 0.548/kWh) while the second best system added PV arrays. This study gives evidence of the key contribution wind turbines make to HRES due to abundant wind resources in the UK, especially in Wales.
The Mongolian and Tibetan Plateaus have experienced warming higher than the global average in recent decades, resulting in many significant changes to ecosystem structures and functions. Among items that show change are the leaf area index (LAI) and evapotranspiration (ET), both of which play a fundamental role in shaping many causes and consequences of land surface processes and climate. This study examines the spatiotemporal changes of the LAI and ET and their relationships on these two roofing landscapes. Based on the MODIS products from 2000 through 2014, we found that there existed a general positive relationship between LAI and ET on the Mongolia Plateau (MP), while synergy did not exist on the Tibetan Plateau (TP). Overall, 49.38% (50.62%) of land areas on the TP experienced significant increases (decreases) in LAI, while on the MP the percentages of increase and decrease were 94.92% (5.09%). For ET, the increased land area was 21.70% (124100 km2) on the TP and 88.01% (341600 km2) on the MP. More importantly, the relationships varied substantially across space and over time, with mismatches found in some parts of the landscapes. Additional observational investigations and/or experimental research are needed to explore the relationships, including the influences of vegetation characteristics and disturbances.
Throughfall, stemflow, evapotranspiration and infiltration are likely to vary with forest types, and consequently affect soil moisture regimes in different soil layers. In this study, the spatial and temporal characteristics of soil moisture were investigated to understand variations in soil moisture in three typical forests, including Phyllostachys pubescens forest (abbreviated as PPF), Schima superba forest (abbreviated as SSF) and Cunninghamia lanceolata forest (abbreviated as CLF) in the upper reaches of Lijiang River basin in southern China. The results showed that, (1) Litterfall and soil physical properties differed significantly in the three typical forests. Infiltration capacity in SSF was more favorable to soil moisture than in PPF and CLF. (2) Large variations were found in soil moisture at different forest stands and depths. Due to complicated vertical structures, there were obvious differences in soil moisture from the 0-20 cm soil layer to the 50-80 cm soil layer. (3) Average soil moisture in each layer was higher in SSF than in PPF and CLF. (4) Soil moisture in different layers correlated closely with precipitation (P<0.01) and the three typical forests had the same change trends with rainfall during the studying period. (5) In topsoil, soil moisture was influenced by soil properties which were mostly determined by litterfall, while in deep soil, soil moisture was affected by variations of soil characteristics, which were mostly determined by root distribution. This study provides a scientific basis for better understanding the relationships between forest vegetation and its hydrological effects, helping to facilitate water resources conservation and achieving wise forest management in the upper reaches of Lijiang River basin.
Data selection and methods for fitting coefficients were considered to test the self-thinning law. The Chinese fir (Cunninghamia lanceolata) in even-aged pure stands with 26 years of observation data were applied to fit Reineke’s (1933) empirically derived stand density rule (N $propto$ d¯ -1.605, N = numbers of stems, d¯ = mean diameter), Yoda’s (1963) self-thinning law based on Euclidian geometry (v¯ $propto$ N -3/2, v¯ = tree volume), and West, Brown and Enquist’s (1997, 1999) (WBE) fractal geometry (w¯ $propto$ d¯ -8/3). OLS, RMA and SFF algorithms provided observed self-thinning exponents with the seven mortality rate intervals (2%-80%, 5%-80%, 10%-80%, 15%-80%, 20%-80%, 25%-80% and 30%-80%), which were tested against the exponents, and expected by the rules considered. Hope for a consistent allometry law that ignores species-specific morphologic allometric and scale differences faded. Exponents α of N $propto$ d¯α, were significantly different from -1.605 and -2, not expected by Euclidian fractal geometry; exponents β of w¯ $propto$ Nβ varied around Yoda’s self-thinning slope -3/2, but was significantly different from -4/3; exponent γ of w¯ $propto$ d¯γ tended to neither 8/3 nor 3.
The location of the homestay agglomeration is closely related to its proximity to the resources environment and the humanities and social environments. From the macroscopic and microscopic aspects, this study uses the analytic hierarchy process and the expert consultation method to construct a relatively comprehensive evaluation system including economic and environmental factors, tourism development factors, geographical environment factors, supporting facilities and operating conditions. The evaluation index system consists of 20 evaluation indexes and 35 evaluation factors. Taking the Baileqiao in Hangzhou and Qianjiadian Town in Beijing as examples, the evaluation indexes are verified and applied. The results show that the main factors affecting the location of the homestay agglomeration are the economic and environmental factors. The evaluation index system is composed of a target layer, a comprehensive evaluation layer, a factor evaluation layer and an index layer. The target layer takes reasonable location of the homestay agglomeration as the overall objective; the comprehensive evaluation layer includes economic and environmental factors (0.4396), tourism development (0.3039), geographic and environmental factors (0.1405), and supporting facilities (0.0545). The comprehensive evaluation scores of Baileqiao and Qianjiadian homestay agglomerations are 92.644 and 88.734, respectively, indicating that both are reasonable homestay sites. This study is helpful for promoting the understanding of the homestay agglomeration location selection and the development and construction of homestay agglomeration sites.
Tourism symbiosis is a social phenomenon consisting of many complex factors, and the reciprocal cooperation among multiple tourist agents at tourist destinations is the crux of the sustainable development of tourism. This study is from the perspective of tourist enterprises, and introduces the Symbiosis Theory of genecology. A quantitative evaluation is used to analyze both the equilibrium state of the combined symbiotic behavior routes and the behavior patterns of tourist enterprises with local governments, community residents, tourists and tourist enterprises around Qinghai Lake. The findings reveal: (1) the symbiotic behavior routes of the multiple tourist agents “E→G-R-T-E” in the Qinghai Lake area are constituted of intense symbiotic indications, while the maximum dimensionality of symbiotic interest of “E→G-R-T-E” is still in the state of disequilibrium and dissymmetry; (2) the symbiotic model of multiple tourist agents “E→G-R-T-E” in the Qinghai Lake area is an asymmetrically positive symbiotic model. It is proposed that, by establishing symbiotic mechanisms for guidance, decisions, supervisory control and profit distribution, the participation mechanism for multiple agents “E-G-R-T” can be further standardized. Moreover, tourist enterprises should be regarded as the primary agents to optimize the symbiotic model for “E→G-R-T-E” through the reinforcement of integrative supply and the construction of integrative effect, and finally promote the integrative symbiotic model of symmetrical reciprocity of the E-R-G-T model “driven by scenic areas, responsive to community residents, affected by local governments and enjoyed by tourists.”
