Land degradation is a global issue receiving much attention currently. In order to objectively reveal the research situation of land degradation, bibliometrix and biblioshiny software packages have been used to conduct data mining and quantitative analysis on research papers in the fields of land degradation during 1990–2019 (data update time was 8 April 2019) in the Web of Science core collection database. The results show that: (1) during the past 20 years, the number of papers on land degradation has increased. According to the number of articles, it is divided into four stages: a low-production exploration period, a developmental sprout period, expansion of the promotion period, and a high-yield active period. (2) Land-degradation research covers 93 countries or regions. The top five countries in terms of research volume are China, the United States, the United Kingdom, Germany, and Australia. China, the United States, and the United Kingdom are the most important countries for international cooperation in the field of land degradation. However, cooperation between countries is not very close overall. (3) Land degradation, degradation, desertification, remote sensing, soil erosion, and soil degradation are high-frequency keywords in the field of land degradation in recent years. (4) The research hotspots in the field of land degradation mainly focus on research directions such as restoration and reconstruction of land degradation, and sustainable management of land resources. (5) The themes of various periods in the field of land degradation are diversified, and the evolutionary relationship is complex. There are 15 evolutionary paths with regard to dynamic monitoring of land degradation, environmental governance of land degradation, and responses of land degradation to land-use change. Finally, the paper concludes that the research directions on land degradation in future include the process, mechanism, and effect of land degradation, the application of new technologies, new monitoring methods for land degradation, theory enhancement, methods and models of ecological restoration, reconstruction of degraded land, multidisciplinary integrated system research, constructing a policy guarantee system for the reconstruction of degraded land, and strengthening research on land resource engineering.

No abstract

Abstract:The mixed Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.), Masson's pine (Pinus massoniana Lamb.), and hardwood forest is a major forest type in China and of national and international importance in terms of its provision of both timber and ecosystem services. However, over-harvesting has threatened its long-term productivity and sustainability. We examined the impacts of timber harvesting intensity on soil physical and chemical properties 10 and 15 years after cutting using the research plots established with a randomized block design. We considered five treatments, including clear cutting and low (13.0% removal of growing stock volume), medium (29.1%), high (45.8%), and extra-high (67.1) intensities of selective cutting with non-cutting as the control. The impact on overall soil properties derived from principal component analysis showed increasing with a rise in cutting intensity, and the most critical impact was on soil nutrients, P and K in particular. Soil nutrient loss associated with timber harvesting even at a low cutting intensity could lead to nutrient deficits in this forest although most of the soil physical properties could be recovered under the low and medium intensities of cutting. These results indicate that clear cutting and the selective cutting of extra-high and high intensities should be avoided in this type of forest in the region.

No abstract

Ecosystem services are important foundations to realize the sustainable development of economy and society. The question of how to quantitatively evaluate ecosystem services in a scientific way is a hot topic among international researchers. Studying the spatial characteristics of ecosystem services in arid regions can provide the theoretical and practical basis for coordinating a sustainable man-land relationship. Altay Prefecture of China, a typical arid region in Central Asia, was taken as the study area. It is on the Silk Road economic belt, which is a key region in the program of developing Western China. Three ecosystem services: water yield, soil conservation, and net primary productivity were quantitatively evaluated. The results show that (1) the spatial distribution pattern has a distinct characteristic of zonality; (2) mountain zone and mountain-oasis ecotone are the hotspots of ecosystem services; and (3) the correlation between water yield and net primary productivity shows a gradual increasing trend as altitude decreases. Objective analysis from the aspect of mechanism is given by discussing the causes of this particular pattern. It is found that altitude and slope have great influence on spatial distributions of ecosystem services, zones with the most amount of services are distributed in 1.5-2 km-altitude and 15-25°-slope. Different human activities in different regions and spatial distance decay of ecosystem services also contribute to the formation of spatial pattern. Thus, overgrazing, logging and mining are prohibited in mountain zones and OPEN ACCESSSustainability 2015, 7 8336 mountain-oasis ecotones. Scholars are encouraged to focus on desert-ecosystem services in the future.

Livelihood diversification is beneficial to mitigate economic and environmental risks and to improve livelihood sustainability and regional sustainable development. Unsettled herder households (UHH), settled herder households (SHH) and farmer households (FH) are different household types in far northwestern China whose livelihood diversification has not been fully explored. By applying a framework of livelihood diversification, this paper presents a comparative analysis of the characteristics and determinants of the diversification of the three household types. The results show that livelihood assets have been unequally distributed, with FH possessing the least assets; however, FH are better than UHH and SHH in the diversification of livelihood activities. Agriculture remains the most important livelihood source. The high-income groups of the three household types have a higher number of livelihood activities but do not necessarily hold an advantage in equality of livelihood activities. Labor capacity and income are positively related to the number of livelihood activities for the three household types. Livestock size is negatively associated with the number of activities of herders. Moreover, age and subsidy have negative impacts on the number of activities for UHH. Based on the findings, we provide policy suggestions on livelihood enhancement and sustainable and effective development of pastoral regions.

No abstract

No abstract