Maowusu Desert Research Articles

Socio-ecological analysis of desertification in the Mu-Us Sandy Land with satellite remote sensing

To understand the contemporary process of desertification in the Mu-Us Sandy Land, China, we assessed the current status of desertification from satellite images. We analyzed the effect of land use by comparing desertification images and GIS-based thematic data. Socioeconomic factors were studied through interviews with local people. The desertified area ratio in each village was related to the sand dune ratio. Desertification in this region was affected by the activity of sand dunes. The revegetated area ratio had a close relationship with the cropland ratio. The development of cropland and surrounding woods contributed to revegetation of desertified land. Desertified areas were distributed mainly in pastoral regions. Critical carrying capacity of grassland for sheep and goats was approximately 2 head/ha. High population density of goats was evident in the severely desertified ranges. Goats were increasingly introduced to earn money through modernization, but they overgrazed fenced pastures. Further environmental education is needed to promote sustainable land use.

Pulmonary toxicity induced by intratracheal instillation of Asian yellow dust (Kosa) in mice

Asian yellow dust (Kosa) causes adverse respiratory health effects in humans. The objective of this study was to clarify the lung toxicity of Kosa. ICR mice (5 weeks of age) were administered intratracheally with Kosa samples—two samples from Maowusu desert and Shapotou desert, one sample consisted of Shapotou Kosa plus sulfate, and natural Asian dust (NAD) from the atmosphere of Beijing—at doses of 0.05, 0.10 or 0.20 mg/mouse at four weekly intervals. The four Kosa samples tested had similar compositions of minerals and concentrations of elements. Instillation of dust particles caused bronchitis and alveolitis in treated mice. The magnitude of inflammation was much greater in NAD-treated mice than in the other particles tested. Increased neutrophils, lymphocytes or eosinophils in bronchoalveolar lavage fluids (BALF) of treated mice were dose dependent. The number of neutrophils in BALF at the 0.2 mg level was parallel to the content of β-glucan in each particle. The numbers of lymphocytes and eosinophils in BALF at the 0.2 mg level were parallel to the concentration of SO 4 2− in each particle. Pro-inflammatory mediators—such as interleukin (IL)-12, tumor necrosis factor-(TNF)-α, keratinocyte chemoattractant (KC), monocyte chemotactic protein (MCP)-l and macrophage inflammatory protein-(MIP)-lα in BALF—were greater in the treated mice. Specifically, NAD considerably increased pro-inflammatory mediators at a 0.2 mg dose. The increased amounts of MlP-lα and TNF-α at 0.2 mg dose corresponded to the amount of β-glucan in each particle. The amounts of MCP-l or IL-12 corresponded to the concentration of sulfate (SO 4 2−) at a 0.2 mg dose. These results suggest that inflammatory lung injury was mediated by β-glucan or SO 4 2−, which was adsorbed into the particles, via the expression of these pro-inflammatory mediators. The results also suggest that the variations in the magnitude of inflammation of the tested Kosa samples depend on the amounts of these toxic materials.

Climatic Features of Rainfall in the Loess Plateau in China

We have researched environmental monitoring to support anti-desertification activities in the Loess Plateau. In this thesis, the spatial distribution, the variance (stability) and the trend of annual precipitation were studied. In addition, the stability of precipitation in the summer rainy season was estimated from the viewpoint of seasonal features of precipitation. The sampling distribution of the mean of the annual precipitation was resampled by the Bootstrap method at each observation point, and the mean of the annual precipitation was estimated by interval estimation. The time series trend of the annual precipitation was analyzed by using the interval estimation mean of the annual precipitation. The stability of precipitation in the summer rainy season was analyzed from the relationship between the precipitation ratio and the precipitation stability index for the period of five days. It seems that the mean of annual precipitation was the lowest in the Tengeri Desert and the Wulanbu Desert. But the region on the Quilian mountain range at the west side of those deserts near Menyuan had much precipitation. The rainfall increased in low-latitude regions. The variation of annual precipitation was the largest in the northern Maowusu Desert, the northeastern Wulanbu Desert, and around Wugong. In contrast, the variations of annual precipitation were small around Menyuan. We could not see a trend for annual precipitation in the whole of the Loess Plateau from 1980 to 2000. However, it seems that there were significant trends at a few observation points. We proposed the rainy season stability index {RSS(j)} based on the relationship between the precipitation ratio PRP(t, j) and the precipitation stability index PSI(t, j). The analysis of the feature of precipitation by using RSS(j) clarified that the rainy season is not equally stable between the east side and the west side of the Loess Plateau, even if the annual precipitation is at the same level.

The study of land desertification in transitional zones between the MU US Desert and the Loess Plateau using RS and GIS?a case study of the Yulin region

In this study, the land desertification of transitional zones of desert loess in the Yulin region (China) is studied from TM images in a geographical information system (GIS). It is found that the desertification in Yulin is still severe. The desertified land accounts for 67.7% of the total land areas. The distribution of desertified land shows obvious spatial imbalance, with severe desertification in northwestern regions and slight desertification in southeastern regions. This imbalance is related to the difference in physical factors and land-use pattern. The process of desertification in Yulin areas shows a steady and even reversed trend between 1987 and 1999, as a result of positive efforts. At the end of the paper the cause of desertification is discussed. It is believed that the interaction and confliction between the natural process and human activities may lead to the development of desertification.

WATER UTILIZATION OF NATURAL AND PLANTED TREES IN THE SEMIARID DESERT OF INNER MONGOLIA, CHINA

We used stable isotope techniques to investigate water utilization of two native trees, Sabina vulgaris Ant. and Artemisia ordosica Krasch., and one introduced tree, Salix matsudana Koidz., in the semiarid Mu-Us desert, Inner Mongolia, China. The study site was in a region where there has been a decline in agricultural productivity, caused by severe desertification over the past several decades. S. matsudana is used extensively for reforestation to protect farms and cultivated lands from shifting sand dunes. We identified water sources for each tree species by comparing the stable isotopes δD and δ18O in water in stems, soil, and groundwater. We also measured δ13C levels in leaves to evaluate the intrinsic water-use efficiency (WUE) of each plant. Comparison of isotopes showed that S. vulgaris and S. matsudana consume relatively deep soil water as well as groundwater, whereas A. ordosica uses only shallow soil water. The δ13C measurements indicated that S. vulgaris has exclusively high WUE, whereas that of the other species was typical of temperate-region C3 plants. The water source data plus WUE data suggest that planted S. matsudana uses groundwater freely, whereas native plants conserve water. Thus, reforestation with S. matsudana might cause irreversible groundwater shortages. Corresponding Editor: E. A. Holland.

毛烏素沙地に生育する５種類の植物のフェノロジーについて

乾燥地や半乾燥地では，水分条件の異なる様々な立地が形成されているため，種組成は豊かであり，高温乾燥環境へ多様な適応がみられる。ここでは乾燥条件に対するフェノロジカルな反応を明らかにするために，中国半乾燥地の毛烏素沙地で在来種(油蒿，檸条，沙柳，臭柏の4種類)および外来種(旱柳)の新梢の伸長成長の経過と環境条件の関係を1年間測定した。油蒿以外は5月初めまでに伸長成長を開始した。その時期は平均気温が連続的に10℃を越えるころであった。油蒿，檸条，沙柳，臭柏の在来種は高温, 乾燥条件にあった7月に成長を休止または終了した。一方，外来種である旱柳は継続して成長を行った。その後，油蒿と臭柏は秋に成長を再開した。2度目の成長は降雨と強い関係をもっていた。在来種のうち沙柳のみが地下水面に近いほど旺盛な成長を示した。

Scale-dependent spatial heterogeneity of vegetation in Mu Us sandy land, a semi-arid area of China

To examine spatial scale-dependent variation in the vegetation in Mu Ussandy land, in the semi-arid area of NW China, two transects (5 kmin length, meeting at right angle) were set, and two vegetation attributes(quantitative descriptors), vegetation cover and number of plant species, wereinvestigated. The data were analyzed combining geostatistics and fractalgeometry. Nested spatial structures were revealed for both vegetationattributes, indicating the existence of multi-scale variations. The largefractal dimensions (> 1.70) commonly found in the vegetation suggest thedominance of small-scale variations. Shifting in fractal dimensions wasdetected, implying scale-dependent spatial variation of the vegetation, as wellas its hierarchical organization. Significant differences in spatial variationof the vegetation attributes between the different directions were also found,suggesting a zonal anisotropy of geomorphologic processes.

Plant species effect on the spatial patterns of soil properties in the Mu-us desert ecosystem, Inner Mongolia, China

Although Artemisia ordosica Krasch. and Sabina vulgaris Ant. are the dominant shrub species in the Mu-us desert ecosystem, they differ in their botanical traits. We investigated the spatial patterns of soil properties using geostatistical analysis to examine the effect of plant species on these spatial patterns. Comparison among three microsite types (under A. ordosica, under S. vulgaris, and the opening between vegetation) showed that A. ordosica generally had less effect than S. vulgaris on local soil properties. The long life-span, prostrate life-form, and evergreen leaf-habit of S. vulgaris may lead to a higher accumulation of organic and fine materials under S. vulgaris. The range of spatial autocorrelation found in the mass of organic matter on the soil surface was smaller than that of the coverage of S. vulgaris (11.5 m) which corresponded to the canopy patch size of this species, and was longer than the canopy patch size of A. ordosica. The ranges of total C and N, and pH (11.7–15.6 m) were similar to that of S. vulgaris. The range of available P (106.3 m) was comparable to that of the coverage of A. ordosica (86.2 m) considered to be the scale of the distribution of this species. The ranges of silt+clay and exchangeable K, Ca, and Mg (31.0–46.7 m) were not related to plant presence, and were similar to that of topography (43.1 m).

Preparation of Artificial Kosa Aerosol with Two Original Desert Sands.

Two kinds of surface soils were sampled at Shapotou in Tengger Desert and Yanchi Shabianzi in Maowusu Desert, two well known areas as origin of sand storm, in order to prepare a typical artificial kosa aerosol. Those original desert soils were separated, by sieving, to three different particle sizes (>100, 100-50, and< 50μm) . The artificial kosa aerosol with particle size around 10μm was successfully separated from particle fraction of < 50μm by wind-driven mode tunnel system. The amount of the two artificial kosa aerosol samples thus prepared were about 2kg each from 250kg (Shapotou) and 150kg (Yanchi Shabianzi) of original desert surface soils with less than 100 μm in particle size. The minerals in artificial kosa aerosol were compared with those in natural ones collected at Lanzhou and in Japan by X-ray diffraction analysis. The artificial samples prepared were found to be very similar to Lanzhou sample rather than Japanese one. The size distributions of these artificial kosa aerosol samples were confirmed similar to a natural sample that was collected at Lanzhou in May 1993 when a strong sand storm occurred.

Development and Afforestation Planning against Desertification and Any Potential of Agricultural Mechanization in the Maowusu Desert, Inner Mongorian Autonomous Region, China (2)

Development and Afforestation Planning against Desertification and Any Potential of Agricultural Mechanization in the Maowusu Desert, Inner Mongorian Autonomous Region, China (2)

Development and Afforestation Planning against Desertification and Any Potential of Agricultural Mechanization in the Maowusu Desert, Inner Mongorian Autonomous Region, China (1)

Development and Afforestation Planning against Desertification and Any Potential of Agricultural Mechanization in the Maowusu Desert, Inner Mongorian Autonomous Region, China (1)

Recent Trends of Desertification in the Maowusu Desert, China

In the Maowusu Desert—which in the south-east encompasses part of the Yulin Region, Shaanxi Province, and in the north-west the Ih Ju League, Inner Mongolia Autonomous Region—desertification trends in relation to the impact of droughts and land-use changes were investigated. Data derived from Earth resources technology satellites (LANDSAT I and LANDSAT II, 1974–1978), and Chinese documentary sources, were used for the analysis. It was found that desert ‘expansion’ occurred during 1953–76, but the rates of expansion varied over time and space, relatively rapid desertification being observed for 1959–63 and 1971–76. The bulk of the expansion was located in the more arid Ih Ju League. The mean annual rate of areal expansion was 6.4% during 1958–71. By comparing the desertification rates with precipitation and land-use information, it was established that droughts have only accentuated the desertification process. The primary cause of desert expansion is the excessive clearing of land for rain-fed agriculture as well, of course, as overgrazing. Another contributory factor was culling of vegetation for fuel and raw materials for handicraft industries.Efforts have been expended on desert control since the mid-1950s, resulting in the arresting of desertification in some local areas. The individual success stories demonstrate that, with mass participation, effective desert control can be achieved by using low-level technology. However, the Chinese programme of desert control was not conceived as a comprehensive programme. Control activities relied almost exclusively on vegetational methods, and they were seldom coordinated with land-use policies as well as with the planning of energy supplies. The negligence of the fundamental conflict between expanding agricultural activities and desert control has led to a net desert expansion in the last 30 years. Recognition of this fundamental conflict and implementation of mitigative land-use policies, would be a major step towards resolving the desertification problem in the Maowusu Desert.