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1. China's Grain for Green Project is a rapid landscape-scale shift in ground cover and land use with significant implications for biodiversity. From 1998 to 2005, we carried out field studies to examine the landscape-level impacts of this project, and to provide a practical example of the successes and failures of a large-scale attempt to restore a vulnerable environment. 2. In a northern part of China's Shaanxi Province, our results indicated that the total vegetation cover in areas covered by this project increased from 29·7% in 1998 to 42·2% in 2005. However, we also found evidence that large-scale afforestation in this vulnerable arid and semi-arid region could increase the severity of water shortages, decrease vegetation cover in afforestation plots, and adversely affect the number of species present. The exclusion of livestock from overgrazed areas and the elimination of cultivation in marginal areas had the biggest effects on the restoration of vegetation cover, whereas tree planting had a strong negative effect in vulnerable areas. 3. Synthesis and applications. In practical terms, the destruction of natural vegetation cover during afforestation should be avoided, as this makes the soil surface more vulnerable to erosion and reduces species diversity. Managers should reduce the intensity of farming and grazing on fragile land rather than relying on afforestation as the primary tool for ecological restoration in arid and semi-arid areas. Afforestation remains a valuable tool but should be limited to the planting of native or other species that will not exacerbate soil water shortages such as stable communities of natural desert steppe, maximum water-use efficiency dwarf shrubs, and possibly even lichen species in more severely degraded environments.

Arid and semi-arid regions are climate-sensitive areas, which account for about 40% of the world's land surface area. Future environment change will impact the environment of these area, resulting in a sharp expansion of arid and semi-arid regions. is a multi-functional tree species with extreme cold, drought and barren resistance, as well as ornamental and medicinal functions. It was found to be one of the most important tree species for ecological restoration in arid and semi-arid areas. However, bioclimatic factors play an important role in the growth, development and distribution of plants. Therefore, exploring the response pattern and ecological adaptability of to future climate change is important for the long-term ecological restoration of in arid and semi-arid areas. In this study, we predicted the potential distribution of in China under different climate scenarios based on the MaxEnt 2.0 model, and discussed its adaptability and the major factors affecting its geographical distribution. The major factors that explained the geographical distribution of were Annual precipitation (Bio12), Min air temperature of the coldest month (Bio6), and Mean air temperature of the coldest quarter (Bio11). However, could thrive in environments where Annual precipitation (Bio12) >150 mm, Min air temperature of the coldest month (Bio6) > -42.5°C, and Mean air temperature of the coldest quarter (Bio11) > -20°C, showcasing its characteristics of cold and drought tolerance. Under different future climate scenarios, the total suitable area for ranged from 411.199×10 km² to 470.191×10 km², which was 0.8~6.14 percentage points higher than the current total suitable area. Additionally, it would further shift towards higher latitude. The MaxEnt 2.0 model predicted the potential distribution pattern of in the context of future climate change, and identified its ecological adaptability and the main climatic factors affecting its distribution. This study provides an important theoretical basis for natural vegetation restoration in arid and semi-arid areas.

Accurate precipitation prediction is very important for social life and economical activity. Prediction of the quantitative precipitation in semi-arid areas is difficult because of rain scarcity and volatility. In this study, the 3-h precipitation situation in the semi-arid region of Lanzhou is predicted, that is, the precipitation status after 3 h is forecasted on 5 levels: ‘no rain’, ‘light rain’, ‘moderate rain’, ‘heavy rain’ and ‘torrential rain’. We selected the meteorological data from 25 stations in and nearby Lanzhou, and processed the data with lag, difference and multiplication. Due to the large number of features, we use Mutual Information (MI) feature extraction method to reduce feature dimension, extract the features that are highly correlated with the target variable, and introduce spatio-temporal information in this way. Precipitation in semi-arid areas also has the problem of sample imbalance. We oversampled the data using Adaptive Synthetic (ADASYN) sampling approach and generated some minority class samples. Based on the MI feature extraction method and the ADASYN oversampling method, we constructed an Adaptive Synthesis and Mutual Information extraction Matrix (ASMI-M), which is the feature matrix used for model training. Then we proposed a Convolutional Neural Network and Long Short Term Memory (CNN-LSTM) model based on deep learning to predict the 3-h precipitation in Lanzhou City, which has achieved better prediction performance than traditional machine learning methods.

The arid and semi-arid regions within China host 75% of the country’s cultivated lands. These regions heavily rely on groundwater for drinking, irrigation, industry and energy production. Understanding recharge and discharge processes is critical to managing sustainable use and development of groundwater resources. Recently, groundwater recharge and discharge have been altered by climate change (air temperature, rainfall) and human activities (e.g. irrigation, pumping, reforestation), resulting in significant changes in the quantity, quality, and spatiotemporal distribution of groundwater resources. This essay describes some examples of the associated issues, challenges and opportunities in the arid and semi-arid areas of China.

Abstract Pastoralism has been the most productive livelihood option in the dryland of the Horn of Africa although recently its sustainability is becoming challenging. Camel is a livestock species uniquely adapted to the arid and semi-arid areas of the region. Camels are predominantly reared in the drier areas of Ethiopia such as Afar, Ethiopian Somali and the eastern and southern parts of Oromia region. This review is aimed at reviewing the camel population, marketing status, challenges and opportunities related to camel production and marketing in Ethiopia. Official reports on the camel population (1.42 million) underestimate the number of camel populations in Ethiopia while different research reports a higher figure of the camel population up to 4.8 million. However, each report indicated an increasing trend in the camel population. Camel is being adopted by different pastoral groups, in which camel rearing was less customary. The economic importance of the camel over other livestock species is immense, particularly during the harsh seasons due to less decline in its prices and the camel is the most expensive in both pastoral and agro-pastoral areas when compared to other livestock. Camel plays an important role in revenue generation, contributing to the earnings from export. Formal camel export status has shown a flat trend and informal export outweighed the formal one. Despite its ecological and economic importance, the camel has been neglected by researchers and the Ethiopian government. Poor market infrastructure, lack of market information, lack of market-oriented production system, the export ban by many countries and the inconvenience of an export regulatory institutional setting are among the major constraints of camel marketing in Ethiopia. Therefore, policy and development interventions are demanded that recognize the social, economic and ecological importance of camels for pastoral communities and the national economy.

Annual species show traits, such as shortleaf lifetimes, higher specific leaf area, and leaf nutrient concentrations, that provided a more rapid resource acquisition compared to perennials. However, the comparison of root traits between the annuals and perennials is extremely limited, as well as the trade-offs of leaf and fine root traits, and resource allocation between leaf and root, which may provide insight into the mechanism of species changes in arid and semi-arid areas. With lab analysis and field observation, 12 traits of leaf and fine root of 54 dominant species from Horqin Sandy Land, Northeastern China were measured. The organization of leaf and fine root traits, and coordination between leaf and fine root traits of annual and perennial plants were examined. Results showed that there were differences between annuals and perennials in several leaves and fine root traits important in resource acquisition and conservation. Annuals had higher leaf area (LA), specific LA (SLA), and specific root length (SRL) but lower leaf dry-matter content (LDMC), leaf tissue density (LTD), leaf carbon concentration (LC), and fine root dry-matter content (FRDMC) than perennials. Leaf nitrogen (LN) concentration and fine root nitrogen concentration (FRN) were negatively related to LTD and FRDMC in annuals, while FRN was positively related to FRTD and fine root carbon concentration (FRC), and LA was positively related to LN in perennials. These implied that annuals exhibited tough tissue and low palatability, but perennials tend to have smaller leaves to reduce metabolism when N is insufficient. Annuals showed significant positive correlations between FRC/FRDMC and LDMC/LTD/LC, suggesting a proportional allocation of photosynthate between leaf and fine root. In perennials, significant negative correlations were detected between LN, LC, and SRL, fine root tissue density (FRTD), as well as between LA and FRTD/FRC. These indicated that perennials tend to allocate more photosynthate to construct a deeper and rigid roots system to improve resource absorption capacity in resource-limited habitats. Our findings suggested that annuals and perennials differed considerably in terms of adaptation, resource acquisition, and allocation strategies, which might be partly responsible for species changes in desertified grasslands. More broadly, this work might be conducive to understand the mechanism of species changes and could also provide support to the management and restoration of desertified grassland in arid and semi-arid areas.

Drought is one of the main constraints affecting crop production in the current climate change scenario. The desert area of Chihuahua in Mexico has limited water availability and is therefore susceptible to drought. Plant photosynthetic performance is the main determining factor of crop productivity, especially under stress conditions. The present study aimed to conduct a comparative analysis of three maize hybrids (P1898, P1445, and P1382) grown under drought stress, focusing on yield, physiological aspects, photosynthetic efficiency, and stomatal activity. A field experiment with these hybrids was carried out in the municipality of Cuauhtémoc, Chihuahua, Mexico, which is characterized by a low precipitation regime. The results indicated that the P1898 hybrid achieved the highest yield and was the best adapted to drought conditions. The analysis of photosynthesis parameters suggests favorable adaptations in both the P1898 and P1382 hybrids such as excess energy dissipation. Additionally, the P1898 hybrid exhibited a greater stomatal area, potentially enhancing CO 2 uptake and heat dissipation via transpiration. The P1382 hybrid demonstrated greater efficiency in photosynthetic energy use and improved water use efficiency (WUE), likely due to its stomatal adaptations. These findings suggest that the P1898 hybrid is the most suitable maize cultivar for cultivation in regions prone to drought and high temperatures, owing to its superior yield and photosynthetic adaptations.

Groundwater recharge is critical to water circulation in arid and semi-arid regions. The accurate determination of groundwater recharge is required for assessing water resources and effectively managing groundwater, especially in water-limited areas. Based on field experiments and numerical models in a semi-arid region, this study assessed the effect of non-isothermal flow on groundwater recharge. A lysimeter was used in the Mu Us Desert, northwestern China, to monitor groundwater recharge from 1 June to 30 September 2018. The numerical models (isothermal and non-isothermal models) were calibrated with the measured soil moisture and soil temperature. Groundwater recharge was found to take up nearly 29% of rainfall. The non-isothermal model was capable of accurately assessing groundwater recharge based on the accurate calculation of evaporation. The isothermal model, however, underestimated the groundwater recharge by 13.2% and overestimated the evaporation by 16.2%. The isothermal model overestimated evaporation during the drying process. In contrast, cumulative net recharge was underestimated after heavy rainfall events. It was therefore suggested that the non-isothermal flux should be considered in semi-arid regions, especially when assessing groundwater recharge.

The ridge-furrow rainfall harvesting system (RFRH) improved the water shortages, and reasonable fertilization can promote nutrient uptake and utilization of crops, leading to better yield in semi-arid regions. This holds significant practical significance for improving fertilization strategies and reducing the application of chemical fertilizers in semi-arid areas. This field study was conducted to investigate the effects of different fertilization rates on maize growth, fertilizer use efficiency, and grain yield under the ridge-furrow rainfall harvesting system during 2013-2016 in semiarid region of China. Therefore, a four-year localization field experiment was conducted with four fertilizer treatments: RN (N 0 kg hm -2 , P 2 O 5 0 kg hm -2 ), RL (N 150 kg hm -2 , P 2 O 5 75 kg hm -2 ), RM (N 300 kg hm -2 , P 2 O 5 150 kg hm -2 ), and RH (N 450 kg hm -2 , P 2 O 5 225 kg hm -2 ). The results showed that the total dry matter accumulation of maize increased with the fertilizer application rate. The nitrogen accumulation was highest under the RM treatment after harvest, average increase by 1.41% and 22.02% (P<0.05) compared to the RH and RL, respectively, whereas the phosphorus accumulation was increased with the fertilizer application rate. The nitrogen and phosphorus use efficiency both decreased gradually with the fertilization rate increased, where the maximum efficiency was observed under the RL. With the increase of fertilizer application rate, the maize grain yield initially increased and then decreased. Under linear fitting, the grain yield, biomass yield, hundred-kernel weight, and ear-grain number all showed a parabolic trend with the increase of fertilization rate. Based on comprehensive consideration, the recommended moderate fertilization rate (N 300 kg hm -2 , P 2 O 5 150 kg hm -2 ) is suitable for the ridge furrow rainfall harvesting system in semiarid region, and the fertilization rate can be appropriately reduced according to the rainfall.

To explore the spatiotemporal niche characteristics and changing regularities of insect communities under lamps in a semi-arid region, this paper analyzed Levins’ niche breadth index and the Pianka niche overlap index of 10 orders and 19 selected common families or superfamilies of insect communities under lamps from April to September 2018 at six vegetation sites in the Habahu National Nature Reserve, a rare desert grassland–wetland reserve in China. The results indicated the following: (1) Different taxa possess varying spatiotemporal, temporal, and spatial niche breadths, suggesting that insects effectively utilized resources in the Habahu Nature Reserve. (2) Among these groups, in terms of the orders aspect, Lepidoptera had the largest temporal niche breadth, the Hemiptera had the largest spatial niche breadth, and Lepidoptera, Coleoptera, and Hemiptera had relatively large spatiotemporal niche breadths, while Odonata had the smallest niche breadth in all three aspects. The orders of Coleoptera and Lepidoptera had the largest spatiotemporal niche overlap value, while Odonata and Diptera had the smallest. (3) In terms of the common families (superfamilies) aspect, Noctuidae had the largest temporal niche breadth and spatiotemporal niche breadth, while Hydrophilidae had the smallest. The spatial niche breadth of Sphingidae was the largest, while Corixidae was the smallest. Noctuidae and Pyraloidea had the largest spatiotemporal niche overlap value among these herbivore groups, Miridae and Chrysopidae, among the herbivore to predatory groups, and Noctuidae and Braconidae, among the herbivore to parasitic groups. This lays a theoretical foundation for developing Chrysopidae and Braconidae as biological control taxa in the Habahu Nature Reserve.