Remote sensing monitoring of the recent rapid increase in cultivation activities and its effects on desertification in the Mu Us Desert, China

The recent ecological improvement in the Mu Us Desert of China, largely attributed to large-scale afforestation projects, has created new opportunities for cultivation activities. However, the subsequent rapid increase in reclamation on desertification land and its impact on desertification have raised concerns. In this study, we first extracted data on cultivated land and desertification land in 1975,1990, 2000, 2005, 2010, 2015, and 2020 through the human-computer interaction visual interpretation method. By overlaying the cultivated land dynamics and desertification land, we subsequently explored the effect of cultivation activities on desertification in the Mu Us Desert during the six periods from 1975 to 2020(1975–1990, 1990–2000, 2000–2005, 2005–2010, 2010–2015, and 2015–2020). The results showed that cultivated land in the Mu Us Desert showed a fluctuating and increasing trend from 3769.26 km~2 in 1975 to 4865.73 km~2 in 2020, with 2010 as the turning point for the recent rapid increase. The main contributors included the large and regular patches distributed in Yuyang District and Shenmu of Shaanxi Province, and relatively smaller patches concentrated in Inner Mongolia Autonomous Region. The increased cultivated land from the reclamation on desertification land was dominated by moderate and severe desertification lands, and the decreased cultivated land that was transferred into desertification land as abandoned cultivated land was dominated by slight and moderate desertification lands. The effect of cultivation activities on desertification reversal(average area proportion of 10.61% for reversed desertification land) was greater than that of the development of desertification(average area proportion of 5.82% for developed desertification land). Nevertheless, compared to reversed desertification land,both the significant increase of developed desertification land during the periods of 2000–2005 and 2005–2010 and the insignificant decrease during the periods of 2005–2010, 2010–2015, and 2015–2020 implied a potential remobilization risk. Therefore, this study provides a significant theoretical reference for the formulation of ecological restoration projects and regional macroeconomic development policies by considering the influence of cultivation activities, to ensure the overall environmental stability and sustainability in desertification land where reclamation and abandonment activities have taken place.

The perception of desertification,its social impact and the adaptive strategies of ecological migrants in the desertification area,China

Based on social influence theory,the Risk-Coping-Social Appraisal model,and data on land desertification,its social influence,and the adaptive measures of 506 households surveyed in Ordos and Bayan Nur,Inner Mongolia,China,we used the Heckman two-stage model and a multinomial logistic model and found the following.First,the perception of land desertification was a prerequisite for eco-migrants to employ adaptive strategies but did not necessarily indicate the adoption of adaptive countermeasures.Second,the social influences eco-migrants experienced at their resettlement site had a significant effect on their ability to employ countermeasures to land desertification.Third,asset variables that reflected migrant's coping ability positively affected perceptions of land desertification and subsequent adaptive countermeasures.To mitigate the negative effects of climate change and land desertification,the local government should encourage migrants to accumulate assets and help migrants to integrate into their new community.This can be achieved by propagandizing information on climate change through a range of channels,diversifying publicity content,and guiding migrants to learn about new technologies and methods for reducing land desertification to minimize related economic losses.

以色列严重退化旱地长期恢复对土壤和植被的影响

Land degradation affects extensive drylands around the world.Due to long-term misuse,the Israeli Sde Zin dryland site has faced severe degradation.The study objective was to assess the feasibility of passive restoration in recovering the site.The study was conducted in four land-units along a preservation-degradation continuum:(1)an area that has not faced anthropogenic disturbances(Ecological land);(2)an area that was proclaimed as a national park in the 1970s(Rehabilitation);(3)an area that was prone,until recently,to moderate anthropogenic pressures(Triangle);and(4)a dirt road that was subjected to long-term off-road traffic(Dirtroad).Soil was sampled and analyzed for its properties.The soil physical quality followed the trend of Ecological land>Rehabilitation>Triangle>Dirtroad.Specifically,high soil salinity in the latter three land-units is attributed to long-term erosional processes that exposed the underlying salic horizons.Herbaceous and shrubby vegetation cover was also monitored.The herbaceous vegetation cover followed the trend of Ecological land(86.4%)>Rehabilitation(40.3%)>Triangle(26.2%)>Dirtroad(2.1%),while the shrubby cover was 2.8%in the Ecological land-unit,and practically zero in the other land-units.It seems that despite the effectiveness of passive restoration in recovering the soil’s physical properties,the recovery of vegetation is limited by the severe soil salinity.