Biodiversity of wild alfalfa pollinators and their temporal foraging characters in Hexi Corridor, Northwest China

Seed production of alfalfa (Medicago sativa L.) is important in determining the effective distribution of new cultivars to farmers. However, little is known about the biodiversity and their community function of native wild pollinators of alfalfa in agronomic systems. We investigated the biodiversity of insects which visited alfalfa flowers and their temporal foraging characters in Hexi Corridor, China. A high biodiversity of insect visitors was discovered, 20 insect taxa in all, including 13 species of Hymenoptera, 3 species of Coleoptera, 3 species of Lepidoptera and 1 species of Diptera. Three native bee species, Andrena squamata, Anthophora melanognatha and Megachile abluta,were validated as the principal pollinators. They showed significant variations in tripping mode and their diurnal distribution patterns. Our results indicated that the native wild bees are diverse and they complement each other. This means they have developed a more complex system for the pollination of alfalfa than has been previously found out.

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The constraints and driving forces of oasis development in arid region: a case study of the Hexi Corridor in northwest China

Scientific Reports ◽

10.1038/s41598-020-74930-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Qiang Bie ◽

Yaowen Xie

Keyword(s):

Arid Region ◽

Driving Forces ◽

Distribution Patterns ◽

Northwest China ◽

Hexi Corridor ◽

Arid Land ◽

Heat Condition ◽

Sustainable Planning ◽

The Index System ◽

Oasis Area

Abstract The oasis, a special landscape with the integration of nature and humanity in the arid region, has undergone an enormous transformation during the past decades. To gain a better understanding of the tradeoff between economic growth and oases stability in the arid land, we took the oases in the Hexi Corridor as a case to explore the constraints of oases development and the driving factors of oases expansion. The dynamic changes and spatial distribution patterns underwent by the oases were examined using multispectral remote sensing imagery. The constraints of oasis development in arid land were investigated by the grid-transformed model, as well as the index system of driving forces was analyzed using the grey incidence model based on the data from statistics yearbooks. The oasis area in the Hexi Corridor had tremendous changes expanded 40% from 1986 to 2015, the stable oasis area was 9062 km2, while the maximum area reached 16,374 km2. The constraints for oases of topography, hydrology and heat condition are as follow: The elevation of oasis ranged from 1000 to 1800 m, peaked in 1500 m; the slope of oasis distribution was flatter than 3 degrees; the aspect of oases on slope land concentrated in northeast and north, accounting for more than 60%. The main driving forces of oasis spatial expansion in the arid region were population, water resource, economy, policies, and other factors. These results are expected to (1) improve the rationality of oasis development, and (2) promote the sustainable planning and management of oases in the arid land.

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Nesting, Sex Ratio and Natural Enemies of the Giant Resin Bee in Relation to Native Species in Europe

Insects ◽

10.3390/insects12060545 ◽

2021 ◽

Vol 12 (6) ◽

pp. 545

Author(s):

Sara Straffon Díaz ◽

Luca Carisio ◽

Aulo Manino ◽

Paolo Biella ◽

Marco Porporato

Keyword(s):

Sex Ratio ◽

Natural Enemies ◽

Native Species ◽

Wild Bees ◽

Trap Nests ◽

Native Bee ◽

New Locations ◽

Negative Impacts ◽

Set Up ◽

North Western

Megachile sculpturalis (Smith, 1853) is the first exotic bee species in Europe. Its remarkably fast expansion across this continent is leading to a growing concern on the extent of negative impacts to the native fauna. To evaluate the interactions of exotic bees with local wild bees, we set up trap nests for above-ground nesting bees on a semi-urban area of north-western Italy. We aimed to investigate the interaction in artificial traps between the exotic and native wild bees and to assess offspring traits accounting for exotic bee fitness: progeny sex ratio and incidence of natural enemies. We found that the tunnels occupied by exotic bees were already cohabited by O. cornuta, and thus the cells of later nesting alien bees may block the native bee emergence for the next year. The progeny sex ratio of M. sculpturalis was strongly unbalanced toward males, indicating a temporary adverse population trend in the local invaded area. In addition, we documented the presence of three native natural enemies affecting the brood of the exotic bee. Our results bring out new insights on how the M. sculpturalis indirectly competes with native species and on its performance in new locations.

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Multi-Temporal Arable Land Monitoring in Arid Region of Northwest China Using a New Extraction Index

Sustainability ◽

10.3390/su13095274 ◽

2021 ◽

Vol 13 (9) ◽

pp. 5274

Author(s):

Xinyang Yu ◽

Younggu Her ◽

Xicun Zhu ◽

Changhe Lu ◽

Xuefei Li

Keyword(s):

Arable Land ◽

Ground Truth ◽

Northwest China ◽

Hexi Corridor ◽

Ground Truth Data ◽

Land Protection ◽

Promising Tool ◽

Study Results ◽

Multi Temporal ◽

The Mean

Development of a high-accuracy method to extract arable land using effective data sources is crucial to detect and monitor arable land dynamics, servicing land protection and sustainable development. In this study, a new arable land extraction index (ALEI) based on spectral analysis was proposed, examined by ground truth data, and then applied to the Hexi Corridor in northwest China. The arable land and its change patterns during 1990–2020 were extracted and identified using 40 Landsat TM/OLI images acquired in 1990, 2000, 2010, and 2020. The results demonstrated that the proposed method can distinguish arable land areas accurately, with the User’s (Producer’s) accuracy and overall accuracy (kappa coefficient) exceeding 0.90 (0.88) and 0.89 (0.87), respectively. The mean relative error calculated using field survey data obtained in 2012 and 2020 was 0.169 and 0.191, respectively, indicating the feasibility of the ALEI method in arable land extracting. The study found that arable land area in the Hexi Corridor was 13217.58 km2 in 2020, significantly increased by 25.33% compared to that in 1990. At 10-year intervals, the arable land experienced different change patterns. The study results indicate that ALEI index is a promising tool used to effectively extract arable land in the arid area.

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Comprehensive assessment of water security for inland watersheds in the Hexi Corridor, Northwest China

Environmental Geology ◽

10.1007/s00254-007-0982-5 ◽

2007 ◽

Vol 55 (2) ◽

pp. 369-376 ◽

Cited By ~ 16

Author(s):

Sheng-chun Xiao ◽

Jin-xiu Li ◽

Hong-lang Xiao ◽

Fa-min Liu

Keyword(s):

Water Security ◽

Northwest China ◽

Hexi Corridor ◽

Comprehensive Assessment

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Abundant Precipitation in Qilian Mountains Generated from the Recycled Moisture over the Adjacent Arid Hexi Corridor, Northwest China

Water ◽

10.3390/w13233354 ◽

2021 ◽

Vol 13 (23) ◽

pp. 3354

Author(s):

Zhihua Zhang ◽

Qiudong Zhao ◽

Shiqiang Zhang

Keyword(s):

Water Vapor ◽

Water Cycle ◽

Precipitable Water ◽

Northwest China ◽

Hexi Corridor ◽

Qilian Mountains ◽

Mountain Areas ◽

Reanalysis Dataset ◽

Weather Forecasts ◽

Endorheic Basin

The observed precipitation was suggestive of abundant precipitation in upstream Qilian mountains and low precipitation in the downstream oasis and desert in an endorheic basin. However, precipitation in mountains generated from the recycled moisture over oasis and desert areas has rarely been studied. The climatological patterns of water vapor from 1980 to 2017 in the Qilian Mountain Region (QMR) and Hexi Corridor Region (HCR) were investigated by the European Centre for Medium-Range Weather Forecasts Interim reanalysis dataset and the Modern-Era Retrospective Analysis for Research and Application, Version 2 reanalysis dataset. The results suggest that the precipitable water content decreases from the adjacent to the mountain areas. There are two channels that transport water vapor from the HCR to the QMR in the low troposphere (surface—600 hPa), suggesting that parts of recycled moisture generated from evapotranspiration over the oasis and desert of the HCR is transported to the QMR, contributing to the abundant precipitation in the QMR. This indicates that the transport mechanism is probably because of the “cold and wet island effect” of the cryosphere in QMR. This is likely one of the essential mechanisms of the water cycle in endorheic river basins, which has rarely been reported.

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Soil Susceptibility to Macropore Flow Across a Desert-Oasis Ecotone of the Hexi Corridor, Northwest China

Water Resources Research ◽

10.1002/2017wr021462 ◽

2018 ◽

Vol 54 (2) ◽

pp. 1281-1294 ◽

Cited By ~ 7

Author(s):

Yongyong Zhang ◽

Wenzhi Zhao ◽

Jianhua He ◽

Li Fu

Keyword(s):

Northwest China ◽

Hexi Corridor ◽

Macropore Flow ◽

Desert Oasis

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Early Cretaceous redbeds from the Minle Basin, Hexi Corridor, northwest China: Mineralogy and geochemistry implications for paleoweathering, provenance, and tectonic settings

Interpretation ◽

10.1190/int-2018-0120.1 ◽

2019 ◽

Vol 7 (2) ◽

pp. T525-T545

Author(s):

Yaxiong Sun ◽

Wenlong Ding ◽

Yang Gu ◽

Gang Zhao ◽

Siyu Shi ◽

...

Keyword(s):

Early Cretaceous ◽

Lower Cretaceous ◽

Chemical Weathering ◽

Tectonic Setting ◽

Active Continental Margin ◽

Northwest China ◽

Hexi Corridor ◽

Sediment Supply ◽

Compositional Variation ◽

Tectonic Settings

Redbeds with a large thickness in the lower Cretaceous record abundant geologic information in the Minle Basin. We have conducted the paleoweathering conditions, provenance, and tectonic settings based on mineralogy and geochemistry. Our results indicate that mudstone samples are characterized by abundant illite with negligible amounts of K-feldspars and analcime. The lower part of the lower Cretaceous is rich in quartz, whereas the upper part is dominated by dolomite and analcime. We suggest that this is caused by the decreasing input of the clastic influx during the middle-late early Cretaceous. High index of compositional variation values (average 1.33) indicate first-cycle sediment supply, suggesting an overall compositional immaturity and short-distance transportation. These characteristics are consistent with an active regional extension tectonic setting. The [Formula: see text] system ([Formula: see text];[Formula: see text];[Formula: see text]) and Th/U versus Th consistently reveal that the lower Cretaceous experienced a positive gradient in chemical weathering from young to old formations. Although the patterns of trace elements in three formations of the lower Cretaceous are different, those of the rare earth elements (REEs) tend to be consistent. The significant enrichment of light REEs, heavy REEs fractionation, and distinctive negative Eu anomalies suggest derivation from an old, upper continental crust composed of predominantly felsic sediments. This interpretation is supported by several discrimination diagrams such as titanium dioxide-nickel ([Formula: see text]), which shows the characteristics of immature recycled sediments. A few sensitive elements, ratios, and normalized REE patterns indicate a provenance of an active continental margin and a continental island arc (CIA). The La-Th-Sc, Th-Co-Zr/10, and Th-Sc-Zr/10 discrimination plots further confirm the CIA signature. Thus, we conclude that the early Cretaceous redbeds in the Minle Basin, Hexi Corridor, were deposited in a dustpan-shaped half-graben basin in a CIA setting when northwest China was influenced by intense regional extension.

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Water Productivity Evaluation under Multi-GCM Projections of Climate Change in Oases of the Heihe River Basin, Northwest China

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16101706 ◽

2019 ◽

Vol 16 (10) ◽

pp. 1706 ◽

Cited By ~ 6

Author(s):

Liu Liu ◽

Zezhong Guo ◽

Guanhua Huang ◽

Ruotong Wang

Keyword(s):

Climate Change ◽

Sustainable Development ◽

River Basin ◽

Water Productivity ◽

Northwest China ◽

Hexi Corridor ◽

Heihe River Basin ◽

Heihe River ◽

Crop Water ◽

The Heihe River Basin

As the second largest inland river basin situated in the middle of the Hexi Corridor, Northwest China, the Heihe River basin (HRB) has been facing a severe water shortage problem, which seriously restricts its green and sustainable development. The evaluation of climate change impact on water productivity inferred by crop yield and actual evapotranspiration is of significant importance for water-saving in agricultural regions. In this study, the multi-model projections of climate change under the three Representative Concentration Pathways emission scenarios (RCP2.6, RCP4.5, RCP8.5) were used to drive an agro-hydrological model to evaluate the crop water productivity in the middle irrigated oases of the HRB from 2021–2050. Compared with the water productivity simulation based on field experiments during 2012–2015, the projected water productivity in the two typical agricultural areas (Gaotai and Ganzhou) both exhibited an increasing trend in the future 30 years, which was mainly attributed to the significant decrease of the crop water consumption. The water productivity in the Gaotai area under the three RCP scenarios during 2021–2050 increased by 9.2%, 14.3%, and 11.8%, while the water productivity increased by 15.4%, 21.6%, and 19.9% in the Ganzhou area, respectively. The findings can provide useful information on the Hexi Corridor and the Belt and Road to policy-makers and stakeholders for sustainable development of the water-ecosystem-economy system.

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