Activities In Arid Regions Research Articles

Benefits of applying hourly resolution in the assessment of the climate aptitude to manage tourist activities in arid regions

The availability of reliable information on local climatic-tourism conditions is a growing need due to the influence it exerts on the quality of the organizational strategy of tourist destination’s, and travel experience. Evaluations of the tourism potential of the climate have been carried out on a daily or monthly resolution, thus limiting the collection of detailed information that makes it possible to fine-tune tourism management and operational decision-making on an intraday scale. This research is the first case study to analyse the climatic suitability for nature tourism, using the weather types method at hourly resolution. The study applies to arid tourist destinations in Isfahan province (Iran). The detailed resolution has made it possible to identify the time slots favourable to the development of nature tourism in those periods of the year recognized as critical in the daily resolution analyses. In the same way, the hourly resolution has also identified critical bands in those periods indicated as favourable in the evaluations to daily resolution. The hourly resolution provides detailed information that can allow tourists and also tourism managers to establish intraday adaptation strategies that make it possible to develop the activity even in places with extreme climates.

Evolution of vegetation cover and impacts of climate change and human activities in arid regions of Northwest China: a Mu Us Sandy Land case

Evolution of vegetation cover and impacts of climate change and human activities in arid regions of Northwest China: a Mu Us Sandy Land case

Assessing Ecological Restoration in Arid Mining Regions: A Progressive Evaluation System

The mining activities in arid regions have resulted in significant ecological environmental issues, exacerbating the already challenging ecological conditions and leading to severe ecosystem damage. Merely relying on natural recovery processes proves inadequate, thus necessitating the implementation of artificial restoration measures to facilitate ecosystem recovery in these arid mining regions. However, it is difficult to scientifically answer the questions of how artificial restoration can be effectively combined with natural recovery, and to what extent can artificial assistance can define the beginning of natural recovery in ecosystems. To address this issue, this study proposed a stepwise ecological restoration model for arid mining regions. The model delineated the ecological restoration process in arid mining regions into three phases: “artificial reconstruction”, “auxiliary ecological restoration”, and “natural recovery”, and constructed an evaluation index system of the stepwise ecological restoration process. Taking an example of a mining ecological restoration in Aksu, Xinjiang, this study examined the evaluation effects of the stepwise ecological restoration model on ecological restoration projects in arid mining regions. The research showed that adopting the stepwise ecological restoration model in arid mining regions can achieve scientific and moderate artificial restoration, better clarify ecological restoration goals, and facilitate the implementation of ecological restoration projects.

Impact of climate-driven oasis evolution on human settlement in the Baiyang River Basin, northwest China, Hami, during the middle to late Holocene

Oases are major foci of human activities in arid regions. Research on the interactions between past climate change, oasis evolution, and human activities may provide an important historical frame of reference for evaluating current and future societal responses to global climate changes. Here, we use optically stimulated luminescence (OSL) and radiocarbon (14C) dating of a sedimentary sequence, combined with analyses of various environmental proxies, to reconstruct the environmental evolution of the Baiyang River Basin, northwest China, during the middle to late Holocene. Additionally, we use a compilation of radiocarbon-dated archaeological sites from the Bronze Age to the historical period to construct a timeline of human activity in the study area. The results show that a flourishing oasis environments were concentrated during the periods of 4.14–2.41 ka BP and after 1.68 ka BP, which corresponded to increases in human settlements during the Bronze Age and after the Tang Dynasty, respectively. By contrast, increased environmental instability during 5.71–4.14 ka BP and 2.41–1.68 ka BP may have hindered human settlement in this area, and the 14C dates show that human activity in the Baiyang River Basin was reduced during those periods. A comparison with regional paleoclimatic records revealed that the evolution of oases was closely related to changes in temperature and precipitation. Higher temperatures in the middle Holocene (∼6–4 ka) caused increases in glacier meltwater production and river discharge, which resulted in a more hydrogenic environment in the downstream oases. Increased humidity in the area during the late Holocene resulted in the re-emergence of oases and therefore of human settlements. Our findings highlight the important relationship between human settlement and land surface processes. We suggest that future warming may cause increased meltwater production and extreme precipitation events, which could adversely impact human societies in arid regions due to more frequent flooding in the downstream oases.

China's oases have expanded by nearly 40% over the past 20 years

AbstractOases are supporters of biological, social, and economic activities in arid regions, which guides their prosperity or decay. Given that China has the largest oases area in the world, determining their evolution is of substantial importance for sustainable development and the ecological protection of these systems. Accordingly, the spatiotemporal evolution of China's oases between 2000 and 2020 was analyzed. This was based on the normalized difference vegetation index derived from moderate imaging spectroradiometer data, combined with superpixel image segmentation, the region adjacency graph merging method, and the genetic algorithm. The results were as follows. Between 2000 and 2020: (1) the oases in China expanded significantly from 207,812 to 289,751 km2; with a total increase of 39.43%; and the number of oases decreased from 135 to 93, which mainly occurred in micro and small oases; (2) the areas of oases in stable, expanding, and shrinking states accounted for 96.77%, 42.65%, and respectively 3.23% of the total oasis area in 2000. Oases have become more concentrated and continuously expanded; (3) the increase in glacial meltwater and precipitation caused by rising temperatures increased the availability of water resources in oases, which provides the substantial basis for expansion; and (4) the primary anthropogenic drivers of oasis expansion and stabilization regions were cultivation and construction, respectively.

Effect of growing conditions on the physiological and biochemical status of remediating plants

This study evaluated the effects of oil pollution, low humidity, and plant co-cultivation in kastanozem on Sorghum bicolor L. Moench and Medicago falcata L. Under the influence of oil pollution, the accumulation of sorghum biomass and the content of its photosynthetic pigments decreased. At the same time, an increase in the concentration of protein in the roots of this plant was not accompanied by an increase in the peroxidase activity. The reduced humidity did not have a negative impact on sorghum. The pollution also reduced the yellow medick biomass and the content of its photosynthetic pigments and proteins in leaves. At the same time, an increase in the protein content in the roots was accompanied by an increase in the peroxidase activity. The low humidity promoted an increase in the concentration of protein in the leaves and an increase in the peroxidase activity in the roots. The plant co-cultivation reflected positively on the sorghum state and negatively on the alfalfa state. The data obtained can be used by phytoremediation technology for kastanozem cleaning up from oil hydrocarbons and rehabilitation of soil biological activities in arid regions.

Assessment of drinking and irrigation water quality using WQI and SAR method in Maâder sub-basin, Ksour Mountains, Algeria

Domestic and agricultural activities in arid regions of Ksour Mountains which stretching across the provinces of Naâma and El Bayadh in Algeria, depend mostly on groundwater due to the region’s climate, which is characterized by low rainfall and high evaporation. The paper aims to assess the suitability of groundwater for drinking and agricultural purposes in the Maâder sub-basin. The data used in this study have been collected from twenty-one (21) groundwater samples from the field. In the laboratory, the major anions and cations were analyzed, and other physicochemical parameters such as temperature, potential hydrogen (pH), electrical conductivity (EC), and total dissolved solids (TDS) were measured in situ. The assessment of water potential for drinking uses was evaluated using the water quality index (WQI). While the evaluation of water quality for irrigation purposes was assessed using the sodium adsorption ratio (SAR). The results revealed that all water quality parameters were within the Algerian standards’ permissible limit. Most of the concentration falls within the allowable limits of World Health Organization standards, except for some samples. The water quality index (WQI) of the study area ranged from 44.71 to 80.67, which means that the groundwater falls into the category of excellent and adequate water. The SAR values varied from 1.06 to 2.78, indicating that all groundwater samples are suitable for irrigation purposes. The obtained spatial distribution maps of WQI and SAR show that groundwater's best quality is located in the northeast part of the study area, and the water quality exhibits a gradual increase in concentration from northeast to southwest. This work helps the decision makers better manage water resources and policy development in the region.

Анализ пространственного распределения сообществ макрозообентоса в равнинной реке полупустынной зоны

Анализ пространственного распределения сообществ макрозообентоса в равнинной реке полупустынной зоны

Response of grassland productivity to climate change and anthropogenic activities in arid regions of Central Asia.

BackgroundQuantitative evaluations of the relative impacts of climate change and anthropogenic activity on grasslands are significant for understanding grassland degradation mechanisms and controlling degraded grasslands. However, our knowledge about the effects of anthropogenic activities and climate change on the grassland in a mountain basin system in arid regions of Central Asia is still subject to great uncertainties.MethodsIn this research, we have chosen the net primary productivity (NPP) as an index for revealing grassland dynamics processes. Moreover, the human appropriation of net primary production (NPPH), which was calculated as the potential NPP (NPPP) minus the actual NPP (NPPA), was applied to distinguish the relative influences of climate change and human activities on the grassland NPP variations in a mountain basin system of Central Asia from 2001–2015.ResultsThe results indicated that the grassland NPPA showed an increasing trend (35.88%) that was smaller than the decreasing trend (64.12%). The respective contributions of human activity, climate change and the two together to the increase in the NPPA were 6.19%, 81.30% and 12.51%, respectively. Human activity was largely responsible for the decrease in the grassland NPPA, with the area experiencing human-induced decreases accounting for 98.21% of the total decreased area, which mainly occurred during spring/autumn pasture and winter pasture. Furthermore, the average grazing pressure index (GPI) values of summer pastures, spring/autumn pasture and winter pastures were 1.04, 3.03 and 1.83, respectively, from 2001–2015. In addition, negative correlations between the NPP and GPI occupied most of the research area (92.41%).DiscussionOur results indicate that: (i) anthropogenic activities were the primary cause of the reduction in the grassland NPP, especially grazing activities. (ii) For areas where the grassland NPP has increased, precipitation was the dominant climatic factor over temperature in controlling the grassland NPP changes in the study area. (iii) The findings of the current research indicate that some measures should be taken to reduce livestock pressure, and artificial grasslands can be built along the Irtysh River and the Ulungur River to relieve grazing pressure on spring/autumn pastures and winter pastures. Our results could provide reliable information for grassland management and the prevention of grassland degradation in arid regions of Central Asia.

Responses of vegetation activity to the daytime and nighttime warming in Northwest China.

Though temperature over the past three decades has shown an asynchronous warming trend between daytime and nighttime, the response of vegetation activity to such non-uniform warming is still not very clear. In this study, the least squares linear trend analysis and geographic information system spatial analysis were conducted to analyze the spatiotemporal patterns of the daytime and nighttime warming based on the daily temperature data from 1982 to 2015 in Northwest China. The normalized difference vegetation index (NDVI) from Global Inventory Monitoring and Modeling System and vegetation type data were used to investigate the responses of vegetation activity to the daytime and nighttime warming using the partial correlation analysis. Our results suggested that (1) there was a very significant increasing trend in both daytime and nighttime temperatures in Northwest China from 1982 to 2015; night temperatures increased about 1.2 times faster than daytime temperatures, showing diurnal asymmetric warming; (2) the responses of vegetation activity to daytime and nighttime warming in Northwest China showed a distinct spatial pattern; the change in night temperatures had a more significant (positive in most regions) effect on vegetation; (3) various types of vegetation responded differently to asymmetric daytime and nighttime warming. Grassland NDVI, broad-leaved, and coniferous forest NDVI significantly responded to daytime warming. Shrub NDVI and desert NDVI significantly responded to night warming. These findings can deepen the understanding of the effects of the daytime and nighttime warming on vegetation activities in arid regions in the context of the current asymmetric warming.

No-tillage reduces competition and enhances compensatory growth of maize (Zea mays L.) intercropped with pea (Pisum sativum L.)

Compensatory growth is a mechanism that explains the recovery in stature and yield of a subordinate crop after the dominant competitor is harvested from an intercropping system. This mechanism might be affected by agronomic practices, particularly those related to the crop water supply in arid regions. The objective of this study was to evaluate the effects of tillage and irrigation practices on competition and compensatory growth in pea-maize intercropping systems at Wuwei station in northwest China from 2014 to 2016. The field experiment included two forms of tillage with plastic film (no-tillage, NT; conventional tillage CT) and three irrigation levels (450 mm, I1; 495 mm, I2; 540 mm, I3). As pea was planted first, it was the dominant competitor and caused greater suppression of maize when crops were grown under I1 > I2 > I3 levels in NT than at the corresponding irrigation levels in CT. Compensatory growth of maize after pea harvest was, on average, 8 to 16% greater in the NT than CT. Growing the intercropped maize strip under NT with plastic mulch was as effective as CT with plastic mulch to achieve a favorable yield outcome. However, the intercropped pea yield was 20–29% greater, with 0–5% more maize yield under deficit irrigation level (I1) and the land equivalent ratio was 3–15% greater in NT than CT plots during this study. Yield gains were related to improved water use efficiency, which was 8 to 18% greater in the intercropping system under NT than CT management. We recommend the NT with plastic mulch method as a water-saving strategy that can sustain the productivity of maize-pea intercropping systems while reducing plastic pollution from agricultural activities in arid regions.

Changes in wetlands and surrounding land cover in a desert area under the influences of human and climatic factors: A case study of the Hongjian Nur region

Wetlands, as the transition zones between land and aquatic systems, are one of nature's most biologically diverse ecosystem types and are important environments for humans. In arid deserts, the roles of wetlands are particularly important. The Hongjian Nur region (HJN), which has the largest desert freshwater lake in China, is not only a national reserve but also the largest breeding ground for Larus relictus in the world. However, due to climate change and human activities, extensive wetland changes have occurred in the HJN region in recent decades. To investigate the changes of wetlands in the HJN region, the dynamics of wetlands and surrounding land cover types in this region over the past three decades were studied using remote sensing. In addition, how these dynamics have been affected by climatic and human factors was analyzed. The results suggested that the area of wetlands presented a decreasing trend over the studied time period from 62.54 km2 to 35.89 km2, with an average rate of change of −0.66 km2/year. The reduction in wetland area was mainly caused by climatic and human factors. The contribution of temperature and precipitation to vegetation growth were small, and the impacts of human activities on the wetland areas of the HJN region were mainly caused by agricultural irrigation, artificial surface expansion and ecological water use. The results also suggested that human activities in arid regions may have negative impacts on fragile wetland ecosystems.

Windblown sand saltation: A statistical approach to fluid threshold shear velocity

The reliable prediction in probabilistic terms of the consequences of aeolian events related to sand transport phenomena is a key element for human activities in arid regions. Threshold shear velocity generating sand lifting is a key component of such a prediction. It suffers from the effect of uncertainties of different origin, such as those related to the physical phenomena, measurement procedures, and modelling. Semi empirical models are often fitted to a small amount of data, while recent probabilistic models needs the probability distribution of several random variables. Triggered by this motivation, this paper proposes a purely statistical approach to fluid threshold shear velocity for sand saltation, treated as a single comprehensive random variable. A data set is derived from previously published studies. Estimates of conditional probability distributions of threshold shear velocity for given grain diameters are given. The obtained statistical moments are critically compared to some deterministic semi empirical models refitted to the same collected data. The proposed statistical approach allows to obtain high order statistics useful for practical purposes.

Hydrological response to land cover changes and human activities in arid regions using a geographic information system and remote sensing.

The hydrological response to land cover changes induced by human activities in arid regions has attracted increased research interest in recent decades. The study reported herein assessed the spatial and quantitative changes in surface runoff resulting from land cover change in the Al-Baha region of Saudi Arabia between 1990 and 2000 using an ArcGIS-surface runoff model and predicted land cover and surface runoff depth in 2030 using Markov chain analysis. Land cover maps for 1990 and 2000 were derived from satellite images using ArcGIS 10.1. The findings reveal a 26% decrease in forest and shrubland area, 28% increase in irrigated cropland, 1.5% increase in sparsely vegetated land and 0.5% increase in bare soil between 1990 and 2000. Overall, land cover changes resulted in a significant decrease in runoff depth values in most of the region. The decrease in surface runoff depth ranged from 25-106 mm/year in a 7020-km2 area, whereas the increase in such depth reached only 10 mm/year in a 243-km2 area. A maximum increase of 73 mm/year was seen in a limited area. The surface runoff depth decreased to the greatest extent in the central region of the study area due to the huge transition in land cover classes associated with the construction of 25 rainwater harvesting dams. The land cover prediction revealed a greater than twofold increase in irrigated cropland during the 2000-2030 period, whereas forest and shrubland are anticipated to occupy just 225 km2 of land area by 2030, a significant decrease from the 747 km2 they occupied in 2000. Overall, changes in land cover are predicted to result in an annual increase in irrigated cropland and dramatic decline in forest area in the study area over the next few decades. The increase in surface runoff depth is likely to have significant implications for irrigation activities.

Response of ants to grazing disturbance at the central Monte Desert of Argentina: community descriptors and functional group scheme

Livestock ranching is one of the main productive activities in arid regions of the world. Grazing produces changes in animal as well as plant communities (e.g. richness, abundance and species dominance relationships). Ants are good biological indicators due to the environmental fidelity of some of their community parameters. We described the functional structure of the ant community in the central Monte of Mendoza, Argentina, and examined the effect of grazing using richness, diversity and the functional group scheme. We used pitfall traps to sample ants at a reserve with 30-year cattle exclusion and at an adjacent ranch. Eleven of the 27 recorded species showed significant differences in their abundance and two species were absent at the ranch. While richness and diversity did not reflect these differences, functional groups did. Hot Climate Specialists were more abundant at the ranch while Cryptic Species and Generalized Myrmicinae increased at the reserve. This study supports the utility of the functional group scheme to study the effects of grazing disturbance in ant communities of arid regions.

Optimum groundwater locations in the northern United Arab Emirates

Due to the increase in urban and agricultural activities in arid regions, the exploration of new locations of possible groundwater discharge and accumulation is required to augment the limited water resources. In order to locate such discharge areas, it is necessary first to identify zones of high recharge potentials. In such an arid region, like the northern United Arab Emirates (UAE), one of the ways to predict areas of potential groundwater recharge is by understanding the hydrological response of its drainage basins to rainfall events. Due to the scarcity of basic hydrological data, a hydrological model driven mainly by information on the physiographic characteristics, drainage network properties (generated from DEM), and surface cover distribution (generated from satellite images) was used to comprehend the dynamics of surface runoff through hydrographs, and hence water loss in the study area. Results show that the northern UAE is drained by 48 drainage basins emerging from the Oman Mountains. Two‐thirds of these basins drain easterly toward the Gulf of Oman, and one‐third drain westerly toward the Arabian Gulf. These basins are found to be structurally controlled by three major fault trends, which are the NE trend (Dibba zone), NW trend (Ham Zone), and WNW trend (Hatta zone). The hydrological response of a basin is correlated with its morphological characteristics. Based on these characteristics, and through the application of a cluster analysis, it was feasible to classify the largest basins in the region into four groundwater potentiality groups in accordance with the magnitude of their peak discharges. From this study, it became evident that the downstream area of the two major basins of Ar‐Rafiah and Limhah, and their vicinities are the most probable sites for groundwater accumulation. The drainage systems of these two basins, especially those controlled by major fault lines, play a vital role in transmitting surface–subsurface rainwater from the Oman Mountains, the recharge zone, into the western desert plain, the discharge zone, where freshwater accumulates underground. The study also revealed that a large volume of groundwater is dissipated into the sea along the eastern coast. A detailed examination of MODIS thermal data supports this by revealing cool surface anomalies issuing from the mountain range toward both the western desert plain and the Gulf of Oman following major rainfall events. Thus, the technique used facilitates the prediction of new locations of optimum groundwater resources in the northern UAE. Such a technique could be adopted, with appropriate modifications, elsewhere in arid regions, where groundwater is restricted and subject to greater complexity.

Field tests of a village-based mollusciciding programme for the control of snail hosts of human schistosomes in Cameroon.

The feasibility of using unskilled workers at the district or village level to perform mollusciciding activities in arid regions of northern Cameroon was investigated. A simplified procedure for application to temporary ponds, the principal sites of schistosomiasis transmission in that region, was tested. This consisted of mixing the required quantity of niclosamide (Bayluscide, Bayer AG, Leverkusen) with pond water in a plastic watering can and applying the mixture around the circumference. To aid dispersion, the can was repeatedly swept from the perimeter toward the centre of the pond. Two ponds each were treated once near the end of the rainy season at 1 of 3 concentrations: 0.5, 1.0 and 1.5 p.p.m. Following treatment, 100% snail mortality was recorded at all concentrations. A simple, rapid method for determining the quantity of niclosamide needed to treat temporary ponds was also devised. Physical characteristics were determined for 16 potential schistosomiasis transmission sites in the region. An integration of those characteristics was used to develop a simplified scale indicating the quantity of niclosamide needed to treat ponds based on their circumference. The operational feasibility of a village based mollusciciding programme using those simplified procedures was then evaluated in 2 villages. Village health workers demonstrated a high accuracy (87%) in identifying potential schistosomiasis transmission foci and snail host populations were virtually eliminated from treated sites.