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31 October 2023, Volume 15 Issue 10 Previous Issue    Next Issue
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Review article
A review of science-policy interface for water governance in the Caspian Sea
Journal of Arid Land. 2023, 15 (10): 1143-1159.   DOI: 10.1007/s40333-023-0030-7
Abstract ( 37 )   HTML ( 675 )     PDF (620KB) ( 165 )  

Science and policy have been interlinked for decades and perform essential nexus conditions in the governing aspects of environmental scenarios. This review paper examines the present challenges in the science-policy interface in terms of water governance in the Caspian Sea and identifies effective conditions that may be used in the current context to enhance the mechanism. The evaluation of the science-policy link in the water policy of the Caspian Sea reveals a gap between knowledge producer and governance system, impeding the translation of scientific information into action. Complicated and context-dependent solutions make it challenging to establish effective science-policy processes in the Caspian Sea water governance settings. Establishing a common governing authority, implementing water and resource management regulations, and protecting the natural environment through legal frameworks are crucial steps to address these concerns and ensure sustainable development. Collaboration among coastal states is essential in environmental, economic, and social aspects of regional development. However, the lack of a comprehensive approach, coherent activities, and effective utilization of national and regional power has hindered efforts to halt the environmental degradation of the Caspian Sea. Local governments need to recognize their responsibility to protect and utilize the Caspian Sea for present and future generations, considering both environmental and human security. The interlinkage of the Caspian Sea water governance with the Organization for Economic Co-operation and Development (OECD) water governance principles offers a framework for policymakers to assess gaps and make necessary amendments to existing mechanisms. Effective science-policy interaction, engagement of diverse stakeholders, institutionalizing agreements, and addressing collective action issues are critical for successful water governance.

Research article
Distribution patterns of fire regime in the Pendjari Biosphere Reserve, West Africa
Journal of Arid Land. 2023, 15 (10): 1160-1173.   DOI: 10.1007/s40333-023-0027-2
Abstract ( 203 )   HTML ( 571 )     PDF (3201KB) ( 318 )  

Pendjari Biosphere Reserve (PBR), a primary component of the W-Arly-Pendjari transboundary biosphere reserve, represents the largest intact wild ecosystem and pristine biodiversity spot in West Africa. This savannah ecosystem has long been affected by fire, which is the main ecological driver for the annual rhythm of life in the reserve. Understanding the fire distribution patterns will help to improve its management plan in the region. This study explores the fire regime in the PRB during 2001-2021 in terms of burned area, seasonality, fire frequency, and mean fire return interval (MFRI) by analysing moderate resolution imaging spectroradiometer (MODIS) burned area product. Results indicated that the fire season in the PBR extends from October to May with a peak in early dry season (November-December). The last two fire seasons (2019-2020 and 2020-2021) recorded the highest areas burned in the PBR out of the twenty fire seasons studied. During the twenty years period, 8.2% of the reserve burned every 10-11 months and 11.5% burned annually. The largest part of the reserve burned every one to two years (63.1%), while 8.3% burned every two to four years, 5.8% burned every four to ten years, and 1.9% burned every ten to twenty years. Only 1.3% of the entire area did not fire during the whole study period. Fire returned to a particular site every 1.39 a and the annual percentage of area burned in the PBR was 71.9%. The MFRI (MFRI<2.00 a) was low in grasslands, shrub savannah, tree savannah, woodland savannah, and rock vegetation. Fire regime must be maintained to preserve the integrity of the PBR. In this context, we suggest applying early fire in tree and woodland savannahs to lower grass height, and late dry season fires every two to three years in shrub savannah to limit the expansion of shrubs and bushes. We propose a laissez-faire system in areas in woodland savannah where the fire frequency is sufficient to allow tree growth. Our findings highlight the utility of remote sensing in defining the geographical and temporal patterns of fire in the PBR and could help to manage this important fire prone area.

Wind regime features and their impacts on the middle reaches of the Yarlung Zangbo River on the Tibetan Plateau, China
ZHANG Yan, ZHANG Zhengcai, MA Pengfei, PAN Kaijia, ZHA Duo, CHEN Dingmei, SHEN Caisheng, LIANG Aimin
Journal of Arid Land. 2023, 15 (10): 1174-1195.   DOI: 10.1007/s40333-023-0066-8
Abstract ( 43 )   HTML ( 4 )     PDF (4201KB) ( 67 )  

The wide valley of the Yarlung Zangbo River is one of the most intense areas in terms of aeolian activity on the Tibetan Plateau, China. In the past, the evaluation of the intensity of aeolian activity in the Quxu-Sangri section of the Yarlung Zangbo River Valley was mainly based on data from the old meteorological stations, especially in non-sandy areas. In 2020, six new meteorological stations, which are closest to the new meteorological stations, were built in the wind erosion source regions (i.e., sandy areas) in the Quxu-Sangri section. In this study, based on mathematical statistics and empirical orthogonal function (EOF) decomposition analysis, we compared the difference of the wind regime between new meteorological stations and old meteorological stations from December 2020 to November 2021, and discussed the reasons for the discrepancy. The results showed that sandy and non-sandy areas differed significantly regarding the mean velocity (8.3 (±0.3) versus 7.7 (±0.3) m/s, respectively), frequency (12.9% (±6.2%) versus 2.9% (±1.9%), respectively), and dominant direction (nearly east or west versus nearly north or south, respectively) of sand-driving winds, drift potential (168.1 (±77.3) versus 24.0 (±17.9) VU (where VU is the vector unit), respectively), resultant drift potential (92.3 (±78.5) versus 8.7 (±9.2) VU, respectively), and resultant drift direction (nearly westward or eastward versus nearly southward or northward, respectively). This indicated an obvious spatial variation in the wind regime between sandy and non-sandy areas and suggested that there exist problems when using wind velocity data from non-sandy areas to evaluate the wind regime in sandy areas. The wind regime between sandy and non-sandy areas differed due to the differences in topography, heat flows, and their coupling with underlying surface, thereby affecting the local atmospheric circulation. Affected by large-scale circulations (westerly jet and Indian monsoon systems), both sandy and non-sandy areas showed similar seasonal variations in their respective wind regime. These findings provide a credible reference for re-understanding the wind regime and scientific wind-sand control in the middle reaches of the Yarlung Zangbo River Valley.

Spatial distribution and ecological risk of heavy metals and their source apportionment in soils from a typical mining area, Inner Mongolia, China
XIE Shicheng, LAN Tian, XING An, CHEN Chen, MENG Chang, WANG Shuiping, XU Mingming, HONG Mei
Journal of Arid Land. 2023, 15 (10): 1196-1215.   DOI: 10.1007/s40333-023-0109-1
Abstract ( 32 )   HTML ( 5 )     PDF (9918KB) ( 65 )  

Determining the distributions and sources of heavy metals in soils and assessing ecological risks are fundamental tasks in the control and management of pollution in mining areas. In this study, we selected 244 sampling sites around a typical lead (Pb) and zinc (Zn) mining area in eastern Inner Mongolia Autonomous Region of China and measured the content of six heavy metals, including cuprum (Cu), Zn, Pb, arsenic (As), cadmium (Cd), and chromium (Cr). The ecological risk of heavy metals was comprehensively evaluated using the Geo-accumulation index, Nemerow general pollution index, and potential ecological risk index. The heavy metals were traced using correlation analysis and principal component analysis. The results showed that the highest content of heavy metals was found in 0-5 cm soil layer in the study area. The average content of Zn, As, Pb, Cu, Cr, and Cd was 670, 424, 235, 162, 94, and 4 mg/kg, respectively, all exceeding the risk screening value of agricultural soil in China. The areas with high content of soil heavy metals were mainly distributed near the tailings pond. The study area was affected by a combination of multiple heavy metals, with Cd and As reaching severe pollution levels. The three pathways of exposure for carcinogenic and noncarcinogenic risks were ranked as inhalation>oral ingestion>dermal absorption. The heavy metals in the study area posed certain hazards to human health. Specifically, oral ingestion of these heavy metals carried carcinogenic risks for both children and adults, as well as noncarcinogenic risks for children. There were differences in the sources of different heavy metals. The tailings pond had a large impact on the accumulation of Cd, Zn, and Pb. The source of Cr was the soil parent material, the source of As was mainly the soil matrix, and the source of Cu was mainly the nearby Cu ore. The purpose of this study is to more accurately understand the extent, scope, and source of heavy metals pollution near a typical mining area, providing effective help to solve the problem of heavy metals pollution.

Nutrient coordination mechanism of tiger nut induced by rhizosphere soil nutrient variation in an arid area, China
TAN Jin, WU Xiuqin, LI Yaning, SHI Jieyu, LI Xu
Journal of Arid Land. 2023, 15 (10): 1216-1230.   DOI: 10.1007/s40333-023-0029-0
Abstract ( 24 )   HTML ( 2 )     PDF (6454KB) ( 197 )  

Tiger nut is a bioenergy crop planted in arid areas of northern China to supply oil and adjust the planting structure. However, in the western region of Inner Mongolia Autonomous Region, China, less water resources have resulted in a scarcity of available farmland, which has posed a huge obstacle to planting tiger nut. Cultivation of tiger nut on marginal land can effectively solve this problem. To fully unlock the production potential of tiger nut on marginal land, it is crucial for managers to have comprehensive information on the adaptive mechanism and nutrient requirement of tiger nut in different growth periods. This study aims to explore these key information from the perspective of nutrient coordination strategy of tiger nut in different growth periods and their relationship with rhizosphere soil nutrients. Three fertilization treatments including no fertilization (N:P (nitrogen:phosphorous)=0:0), traditional fertilization (N:P=15:15), and additional N fertilizer (N:P=60:15)) were implemented on marginal land in the Dengkou County. Plant and soil samples were collected in three growth periods, including stolon tillering period, tuber expanding period, and tuber mature period. Under no fertilization, there was a significant correlation between N and P contents of tiger nut roots and tubers and the same nutrients in the rhizosphere soil (P<0.05). Carbon (C), N, and P contents of roots were significantly higher than those of leaves (P<0.05), and the C:N ratio of all organs was higher than those under other treatments before tuber maturity (P<0.05). Under traditional fertilization, there was a significant impact on the P content of tiger nut tubers (P<0.05). Under additional N fertilizer, the accumulation rate of N and P was faster in stolons than in tubers (P<0.05) with lower N:P ratio in stolons during the tuber expansion period (P<0.05), but higher N:P ratio in tubers (P<0.05). The limited availability of nutrients in the rhizosphere soil prompts tiger nut to increase the C:N ratio, improving N utilization efficiency, and maintaining N:P ratio in tubers. Elevated N levels in the rhizosphere soil decrease the C:N ratio of tiger nut organs and N:P ratio in stolons, promoting rapid stolon growth and shoot production. Supplementary P is necessary during tuber expansion, while a higher proportion of N in fertilizers is crucial for the aboveground biomass production of tiger nut.

Nitrogen application levels based on critical nitrogen absorption regulate processing tomatoes productivity, nitrogen uptake, nitrate distributions, and root growth in Xinjiang, China
JING Bo, SHI Wenjuan, DIAO Ming
Journal of Arid Land. 2023, 15 (10): 1231-1244.   DOI: 10.1007/s40333-023-0108-2
Abstract ( 23 )   HTML ( 4 )     PDF (1004KB) ( 279 )  

The unreasonable nitrogen (N) supply and low productivity are the main factors restricting the sustainable development of processing tomatoes. In addition, the mechanism by which the N application strategy affects root growth and nitrate distributions in processing tomatoes remains unclear. In this study, we applied four N application levels to a field (including 0 (N0), 200 (N200), 300 (N300), and 400 (N400) kg/hm2) based on the critical N absorption ratio at each growth stage (planting stage to flowering stage: 22%; fruit setting stage: 24%; red ripening stage: 45%; and maturity stage: 9%). The results indicated that N300 treatment significantly improved the aboveground dry matter (DM), yield, N uptake, and nitrogen use efficiency (NUE), while N400 treatment increased nitrate nitrogen (NO3--N) residue in the 20-60 cm soil layer. Temporal variations of total root dry weight (TRDW) and total root length (TRL) showed a single-peak curve. Overall, N300 treatment improved the secondary root parameter of TRDW, while N400 treatment improved the secondary root parameter of TRL. The grey correlation coefficients indicated that root dry weight density (RDWD) in the surface soil (0-20 cm) had the strongest relationship with yield, whereas root length density (RLD) in the middle soil (20-40 cm) had a strong relationship with yield. The path model indicated that N uptake is a crucial factor affecting aboveground DM, TRDW, and yield. The above results indicate that N application levels based on critical N absorption improve the production of processing tomatoes by regulating N uptake and root distribution. Furthermore, the results of this study provide a theoretical basis for precise N management.

Temporal and spatial responses of ecological resilience to climate change and human activities in the economic belt on the northern slope of the Tianshan Mountains, China
ZHANG Shubao, LEI Jun, TONG Yanjun, ZHANG Xiaolei, LU Danni, FAN Liqin, DUAN Zuliang
Journal of Arid Land. 2023, 15 (10): 1245-1268.   DOI: 10.1007/s40333-023-0070-z
Abstract ( 46 )   HTML ( 5 )     PDF (5051KB) ( 248 )  

In the Anthropocene era, human activities have become increasingly complex and diversified. The natural ecosystems need higher ecological resilience to ensure regional sustainable development due to rapid urbanization and industrialization as well as other intensified human activities, especially in arid and semi-arid areas. In the study, we chose the economic belt on the northern slope of the Tianshan Mountains (EBNSTM) in Xinjiang Uygur Autonomous Region of China as a case study. By collecting geographic data and statistical data from 2010 and 2020, we constructed an ecological resilience assessment model based on the ecosystem habitat quality (EHQ), ecosystem landscape stability (ELS), and ecosystem service value (ESV). Further, we analyzed the temporal and spatial variation characteristics of ecological resilience in the EBNSTM from 2010 to 2020 by spatial autocorrelation analysis, and explored its responses to climate change and human activities using the geographically weighted regression (GWR) model. The results showed that the ecological resilience of the EBNSTM was at a low level and increased from 0.2732 to 0.2773 during 2010-2020. The spatial autocorrelation analysis of ecological resilience exhibited a spatial heterogeneity characteristic of "high in the western region and low in the eastern region", and the spatial clustering trend was enhanced during the study period. Desert, Gobi and rapidly urbanized areas showed low level of ecological resilience, and oasis and mountain areas exhibited high level of ecological resilience. Climate factors had an important impact on ecological resilience. Specifically, average annual temperature and annual precipitation were the key climate factors that improved ecological resilience, while average annual evapotranspiration was the main factor that blocked ecological resilience. Among the human activity factors, the distance from the main road showed a negative correlation with ecological resilience. Both night light index and PM2.5 concentration were negatively correlated with ecological resilience in the areas with better ecological conditions, whereas in the areas with poorer ecological conditions, the correlations were positive. The research findings could provide a scientific reference for protecting the ecological environment and promoting the harmony and stability of the human-land relationship in arid and semi-arid areas.