Desert Margin Research Articles

The First Observation of the Vulnerable Sooty Falcon falco concolor in Iraq

Sooty Falcon Falco concolor is small to medium-sized, greysh, migrant Falcon, breeds mainly in islands’ cliffs around Arabia and inland in Libya and Egypt, and migrates to east Africa. This species in classified as Vulnerable (VU) in the IUCN Red List. During one of the regular surveys conducted by the Iraqi Organization for Conservation of Nature (IOCN), the first Sooty Falcon for Iraq was found at Zibliya area close to Dalmaj protected area, approx. 35km northeast of Diwaniya city in the Middle Euphrates region of Iraq. The habitat where the first Sooty Falcon was found consists of open farms with desert margins in addition to intensive, long rows of tall trees (Tamarix aphylla) distributed in different locations within Zibliya area. Considerable list of Passerines and other small bird species were also found in the area that might form preferred food items for Sooty Falcon. This observation represents the first record of Sooty Falcon for Iraq.

Water source and transmission in Haloxylon ammodendron in the desert margin of the Manas River Basin, China

Abstract Analysis of water source and moisture transfer characteristics of desert plants is of great significance for ecological restoration in arid areas. In this study, the water source utilized by the desert plant, Haloxylon ammodendron, was analysed using the stable isotope technique, and the water transportation characteristics were obtained based on the proportional heat balance method under different weather conditions. The results showed that (1) before raining, the moisture of H. ammodendron mainly relied on groundwater (the average contribution rate was 34.14%) and on soil water located at a depth of 120–180 cm (the average contribution rate was 29.87%). After the rain, H. ammodendron mainly absorbed soil water from a depth of 60–120 cm (the average contribution rate was 33.19%) and groundwater (the average contribution rate was 30.67%); (2) the stem flow of H. ammodendron showed an obvious diurnal variation, showing a “midday rest” phenomenon. The stem flow showed a peak value, and in sunny days, it was ~2 fold higher than that in cloudy days. (3) The stem flow rate of H. ammodendron varied regularly overtime as follows: August > July > September > June > May, and the meteorological factors affecting its stem flow were solar radiation (0.826) > atmospheric temperature (0.598) > humidity (-0.573). The results provide basic support for the ecological conservation of the desert plant H. ammodendron, while also having important implications for ecological restoration in arid regions.

The Productive Landscape in the Desert Margin for the Sustainable Development of Rural Settlements: An Innovative Greenbelt for Maranjab Desert in Iran

About two billion rural individuals depend on agricultural systems associated with a high amount of risk and low levels of yield in the drylands of Asia, Africa, and Latin America. Human activities, climate change and natural extreme events are the most important drivers of desertification. This phenomenon has occurred in many regions of Iran, particularly in the villages in the periphery of the central desert of Iran, and has made living in the oases so difficult that the number of abandoned villages is increasing every year. Land abandonment and land-use change increase the risk of desertification. This study aims to respond to the research questions: (i) does the planning of green infrastructures on the desert margin affect the distribution and balance of the population? (ii) how should the green belt be designed to have the greatest impact on counteracting desertification?, and (iii) does the design of productive landscape provide the solution? Through a wide-ranging and comprehensive approach, this study develops different scenarios for designing a new form of green belt in order to sustainably manage the issues of environmental protection, agricultural tradition preservation and desertification counteraction. This study proposes a new-traditional greenbelt including small low-cost and low-tech projects adapted to rural scale.

Materiality, inequality, and future‐making as focal points of future engagement of economic anthropology with climate change

Materiality, inequality, and future‐making as focal points of future engagement of economic anthropology with climate change

Largest on earth: Discovery of a new type of fairy circle in Angola supports a termite origin

1. Circular bare patches occur in high numbers among the vegetation of the Namib Desert margin. There is an ongoing scientific debate on the origin of these so‐called “fairy circles” (FCs). One of the most frequently discussed hypotheses regards the bare patches to be the result of localised herbivory by sand termites of the genus Psammotermes (family Rhinotermitidae).2. In all earlier publications, the fairy circles of the Namib Desert region within their entire range from Angola through Namibia to South Africa were, in principle, regarded to be of one type, albeit increasing in size towards the north. Here we present evidence that at −16.23° latitude there is an abrupt discontinuity which separates the FCs on either side from each other.3. South of this discontinuity all studied FCs share the properties of the previously described fairy circles in Namibia and South Africa, especially the presence of Psammotermes termites.4. In contrast, north of −16.23°S the FCs are much larger and are caused by a different and undescribed termite species, most closely related to the harvester termite genus Microhodotermes (family Hodotermitidae). The two sets of fairy circles differ in a specific set of morphological features, associated termites, and soil parameters.5. The observed juxtaposition of the newly discovered large structures caused by a hodotermitid termite and the Psammotermes FCs caused by a rhinotermitid species is interpreted as an interesting example of convergent evolution resulting in similar ecological structures.

The accuracy improvement of clear-sky surface shortwave radiation derived from CERES SSF dataset with a simulation analysis

Towards the Xiaotang region along the northern margin of the China's largest desert, a quantitative assessment of the precision of clear-sky satellite observations (the Single Scanner Footprint TOA/Surface Fluxes and Clouds downward surface shortwave radiation product of Clouds and the Earth's Radiant Energy System (CERES), DSSRCER) is conducted, the localized inversion mode of “absolutely clear-sky” downward surface shortwave radiation (DSSR) is established, and the “absolutely clear-sky” DSSR in Xiaotang during 2005–2018 is simulated by the Santa Barbara Discrete Atmospheric Radiative Transfer (SBDART) model. In general, under the “absolutely clear-sky” condition of Xiaotang region, there is a significant error in DSSRCER, and the simulated results of SBDART (DSSRSBD) with same input parameters as DSSRCER is better and more comparable. Single scattering albedo (SSA), asymmetry parameter (ASY) and aerosol optical depth (AOD) play crucial roles in deciding the accuracy of DSSR, and after parameter adjustment, the DSSRSBD is better than the initial, which is improved remarkably with all indexes of the fitting results greatly improved. The temporal variation of the DSSR during 2005–2018 indicates that the highest annual average value is found in 2008 (770.00 W·m−2), while the lowest appears in 2010 (600.97 W·m−2). Besides, the highest seasonal mean DSSR appears in summer, which between 860.6 and 935.07 W·m−2, while reaches the lowest in winter (403.79–587.53 W·m−2). Moreover, the monthly average DSSR changes as a curve with a single peak and is close to normal distribution, the highest appears in June (934.61 W·m−2), while the minimum with the value of 390.34 W·m−2 is found in December. All of the solar elevation angle, the characteristics of climate and aerosol particles in different seasons may contribute to the temporal variation.

Fluvial incision caused irreversible environmental degradation of an ancient city in the Mu Us Desert, China

AbstractAncient cities are excellent spatiotemporal indicators for the study of historical human activities and environmental change. The ancient city of Sanchahe is located at the southern margin of the Mu Us Desert, China. It is an ideal location for studying the complex relationships between historical desertification and human activities. Field observations of the ancient city walls, a well, and a spring, as well as 14C dating, grain size, spatial analysis of archaeological sites, and analyses of historical seismicity, indicated that neotectonics may have contributed to crustal uplift and accelerated fluvial incision of the Wuding River. This rapid incision caused a decline in groundwater levels, which is an important reason for the irreversible environmental degradation around Sanchahe city over the past 800 yr. This study provides new evidence for such environmental degradation and may contribute to a better understanding of historical desertification in the Mu Us Desert.

Marking the sacral landscape of a north Arabian oasis: a sixth-millennium BC monumental stone platform and surrounding burials

AbstractPrehistoric stone structures are prominent and well-studied in the Levantine desert margins. In northern Arabia, however, such structures have received less attention. This article presents the results of investigations of a 35m-long stone platform, first constructed in the mid sixth millennium BC, overlooking the oasis of Dûmat al-Jandal in northern Saudi Arabia. Excavation of the platform has yielded bioarchaeological and cultural remains, along with evidence for several phases of construction and intermittent use down to the first millennium BC. Analysis of the platform and nearby tombs highlights the persistent funerary and ritual use of this area over millennia, illuminating nomadic pastoralist lifeways in prehistoric Arabia.

Locally recycled late Pleistocene loess feeds modern dust storms at the desert margins of the eastern Mediterranean, Israel

Abstract Current dust storms, originating from afar, are common in Israel and the eastern Mediterranean, and thus most dust sources are considered to be distal. However, recent studies suggest that the latest Quaternary loess accreted in the Northern Negev can also serve as a proximal source of dust. These sources were mostly neglected in past discussions as contributors of dust. Here, we demonstrate that such proximal dust sources, mostly the Negev loess, currently contribute relatively large amounts of recycled dust to the regional dust cycle. We conducted a sampling campaign of deposited dust during individual dust storms and identified high content of coarse silt grains and quartzo-feldspathic minerals within and adjacent to the Negev loess that gradually decreases toward the north. These grains, characteristics of the Negev loess, indicate a short transport distance. In addition, our data reveal that local wind speed is the limiting factor for emitting proximal dust, regardless of the synoptic system. We determined that proximal sources in Israel emit dust during either local events or as a part of regional dust storms originating from afar. We evaluate the minimal contribution of this proximal dust to the total mass of deposited dust as 58–74%, 54–70%, 52–64%, and 26–34% for northern Negev, central Negev, central mountainous region, and northern Israel, respectively. These estimates indicate that at the desert fringe, both proximal and distal sources of dust should be considered when inferring dust sources from dust geochemistry that can sometimes be similar due to the long dust history.

Holocene climatic instability record in the southeastern margin of Mu Us Desert

Holocene climatic instability record in the southeastern margin of Mu Us Desert

Drought-induced tree growth decline in the desert margins of Northwestern China

Water deficiency is the primary limiting factor for tree growth in arid and semi-arid areas. Droughts associated with rising temperatures have increased in severity and frequency globally over the past few decades, making the trees in the drought-prone sites first be affected by water shortages. However, our understanding of tree growth status in these areas, and of their response to drought, is currently insufficient; especially in the context of global warming. Here, we studied 94 Chinese pine (Pinus tabulaeformis) and 86 spruce (Picea crassifolia) trees from different altitudes [2,100–2400 m above sea level (a.s.l.)] distributed at the desert margins of Northwestern China to explore tree growth and drought response from multiple perspectives using dendroecological approaches. Significant growth decline, across all tree species and altitudes, was detected in response to an interdecadal trend towards a drier climate. Moreover, the extent of tree growth decline, the proportion of affected trees, and the degree of moisture dependence have all tended to increase in each sample site, most likely due to enhanced drought severity and duration in recent decades. The more sensitive and susceptible trees were found at lower elevations (drier sites) and may signify a higher vulnerability to heating-induced drought stress. Tree resistance to drought showed strong negative correlation with drought severity across all sample sites. However, the connection between post-drought tree resilience and drought intensity is weak, perhaps because the samples were all collected from living trees, while those that had died were not sampled. The priority for future work should be to combine surviving and dead trees simultaneously, thus achieving a more representative view of tree resilience to drought; this will improve our knowledge of forest dynamics and even ecosystem succession in these vulnerable and sensitive environments.

Aerosols chemical composition, light extinction, and source apportionment near a desert margin city, Yulin, China.

Daily PM10and PM2.5 sampling was conducted during four seasons from December 2013 to October 2014 at three monitoring sites over Yulin, a desert margin city. PM10 and PM2.5 levels, water soluble ions, organic carbon (OC), and elemental carbon (EC) were also analyzed to characterize their chemical profiles. bext (light extinction coefficient) was calculated, which showed the highest in winter with an average of 232.95 ± 154.88 Mm−1, followed by autumn, summer, spring. Light extinction source apportionment results investigated (NH4)2SO4 and NH4NO3 played key roles in the light extinction under high RH conditions during summer and winter. Sulfate, nitrate and Ca2 + dominated in PM10/PM2.5 ions. Ion balance results illustrated that PM samples were alkaline, and PM10 samples were more alkaline than PM2.5. High SO42−/K+ and Cl−/K+ ratio indicated the important contribution of coal combustion, which was consistent with the OC/EC regression equation intercepts results. Principal component analysis (PCA) analyses results showed that the fugitive dust was the most major source of PM, followed by coal combustion & gasoline vehicle emissions, secondary formation and diesel vehicle emissions. Potential contribution source function (PSCF) results suggested that local emissions, as well as certain regional transport from northwesterly and southerly areas contributed to PM2.5 loadings during the whole year. Local government should take some measures to reduce the PM levels.

Palaeoenvironmental reconstruction of Kathu Pan, South Africa, based on sedimentological data

Several studies have highlighted the importance of collecting well-dated records of palaeoenvironmental changes on desert margins, particularly in the semi-arid interior of southern Africa. Here we describe sediments at three sites in Kathu Pan, a pan complex overlying karstic bedrock at the southern edge of the Kalahari Basin. Sinkholes have exposed sedimentary sequences dating back to the Pleistocene, making it possible to document multiple palaeoenvironmental regimes in this landscape. Using a multi-analytical sedimentological approach, including micromorphology, energy dispersive X-ray spectrometry, electron microprobe, loss-on-ignition, laser diffractometry and luminescence dating, we demonstrate that the sediments at Kathu Pan represent an environment fluctuating among a number of thresholds for accumulation of different kinds of transported and authigenic sediments. Within the Pleistocene sands at the base of our studied sedimentary sequence, the presence of palygorskite, indicative of less extreme evaporative control, represents a semi-arid environment from 156 ± 11 ka to 32 ± 2 ka (Marine Isotope Stages 6–3). Increased moisture availability at 84 ± 4 ka and at 96 ± 5 ka (possibly during Marine Isotope Stages 5a and 5c, respectively) is reflected in the sands by the formation of palygorskite in concert with the deposition and oxidation of organic material. As the climate became increasingly arid, possibly in response to global cooling during the Last Glacial Maximum (21 ± 2 ka), Kathu Pan crossed a threshold, and deposition of CaCO3 dominated over that of palygorskite. In the Holocene beds within our studied unit, alternating CaCO3- and organic-dominated deposits, sometimes in very fine laminae, reflect an increase in the amplitude of either seasonal or annual changes in water availability.

Soil microbiotic homogenization occurred after long‐term agricultural development in desert areas across northern China

AbstractSoil microbial communities respond significantly to long‐term agricultural development in desert areas. Because soil microbial communities are distinct in various deserts at different eco‐climate regions, their response patterns to agricultural development are diverse at a local scale. However, whether the different response patterns had some commonalities across various types of deserts at a larger spatial scale remained unclear. To address this question, historical soil samples, collected in different years from pairwise long‐term experimental plots (desert and farmland) at five field stations of the Chinese Ecosystem Research Network across northern China, were analyzed through high‐throughput sequencing approach. Here, we found that soil bacterial communities were sharply different between deserts and agricultural lands. Contrasting to desert soils with higher relative abundances of Actinobacteria and Firmicutes, agricultural soils harbored higher relative abundances of Proteobacteria, Acidobacteria, and Planctomycetes and exhibited higher bacterial α‐diversity with less variation. More importantly, higher community similarities were found in agricultural lands for each station and all stations, suggesting that soil microbiotic homogenization occurred at both local and regional scales after long‐term agricultural development in desert areas. Further analyses revealed that the homogenization was due to the loss of desert‐endemic species and the range expansion of generalist species, which might result from the introduction of crops combined with agricultural practices. The soil microbiotic homogenization associated with the loss of endemic species should be paid special attention to because this might imply the decrease in ecological resilience to perturbations and might lead to rapid desertification in desert margin areas.

Monitoring of Land Degradation and Desertification in the South of Jabal Al Akhdar Mountain in North East Libya

Over the last few decades, global warming and human activities have led to changes and deterioration in natural vegetation across the world. Land degradation in arid, semi-arid areas led to the emergence of desertification especially areas that are located along the desert margins. The Al Jabal Al Akhdar Mountains (The green Mountain) in the north east Libya is one of those areas that have experienced changes in vegetation cover. This region has environmental and economic importance in providing habitat for wildlife and services for local communities and cities in the Libyan Desert. This research will investigate natural vegetation dynamics in the Al Jabal Al Akhdar region using remote sensing techniques in an attempt to monitoring the desertification over the last 42 years to determine the factors that have caused this problem. The overall aim of this paper was to evaluate the factors which have affected vegetation cover change in the Al Jabal Al Akhdar region over the last 42 years.

Indigenous Knowledge Systems and the Teaching of Climate Change in Zimbabwean Secondary Schools

Indigenous African education grew out of the immediate environment, real or imaginary, where people had knowledge of the environment. Indigenous education inculcated a religious attitude that imbued courtesy, generosity, and honesty. At colonization, Africans were thought of as primitive although they had their own systems, contents, and methods of education. Colonialism signified the decline in the importance of indigenous knowledge systems (IKS). By shifting focus in the core curriculum from teaching/learning based on Western science to teaching/learning through IKS as a foundation for all education, it is anticipated that all forms of knowledge, ways of knowing, and world views be acknowledged as equally valid, adaptable, and complementary to one another in equally valuable ways. The uniqueness of indigenous people and their knowledge is inextricably connected to their lands, which are situated primarily at the social-ecological margins of human habitation such as tropical forests and desert margins. It is at these margins that the consequences of climate change manifest themselves in the following sectors: agriculture, pastoralism, fishing, hunting and gathering, and other subsistence activities, including access to water. Government policies in Zimbabwe often limit options and thus undermine indigenous peoples’ efforts to adapt. IKS is very important for community-based adaptation and mitigation actions in the agricultural sector for maintenance of resilience of social-ecological systems at a local level. This article, through interviews, document analysis, and personal observations, proposes that it is best for Zimbabwe to develop her own climate change curricula and modes of delivery that incorporates IKS.

Anzo, The First Evidence of Paleolithic Cave Sites in the Northern Margin of the Iranian Central Desert, Semnan, Iran.

The archaeological survey of the southern foothills of Alborz Mountains was conducted in search of caves and rock shelters with Palaeolithic remains. The region under investigation in Semnan Province is located in the northwestern margins of Dasht-e Kavir in Iranian Plateau. It was investigated primarily in 1980s and 1990s by Iranian archaeologists. From 2009, The Paleolithic Survey of the Iranian Central Desert Project (PSICDP) was established in order to evaluate the Paleolithic potential of the region, as a result of which Palaeolithic sites were documented and their surface collections were published. The current survey was conducted as a part of PSICDP project in autumn 2017. As a result, 12 caves and rock shelters were recorded, despite the promising condition of which only one had evidence from Palaeolithic Period. Anzo Cave, in northwest of Mehdishahr, was the only cave which yielded few number of chipped stones on the outer slope of the cave. The results of this survey raise the possibility that movement patterns of Palaeolithic hunter-gatherers in the region included seasonal-vertical movements between mountainous area in the north and southern lowlands. Recent discovery of Anzo Cave re-emphasizes the significance of the region as a part of migratory pathways during the Pleistocene.

Spatial distribution of sand dunes and their relationship with fluvial systems on the southern margin of the Taklimakan Desert, China

The landscape in desert margin regions is simultaneously shaped by both wind and water forces, resulting in a particular spatial distribution of dunes. It has been suggested previously that aeolian and fluvial systems should be integrated in investigations of the development of regional landforms. We carried out a comprehensive study of landforms on the southern margin of the Taklimakan Desert, China based on remote sensing images, meteorological data and morphodynamic theories of dune formation. Our results indicate that the major characteristic of dunes in this region is the coexistence of dunes with different orientations in a small geographical area. As the development of dunes is mainly determined by the wind regime and the availability of sand, the coexistence of dunes with different orientations might be caused by differences in the availability of sand. The topographic relief and fluvial systems both affect the grain size distribution and the amount of sediment in different regions, resulting in variations in the availability of sand. A comprehensive analysis of the spatial distribution of dunes and the regional environment can help our understanding of the regional variations of sediment in aeolian–fluvial interaction systems and help to model the development of landforms in these environments.

Effect of groundwater depth on riparian plant diversity along riverside-desert gradients in the Tarim River

Riparian plant diversity is sensitive to changes in groundwater in arid regions. However, little is known about how plant diversity responds to changes in environment along riverside-desert gradients in riparian ecosystem. Our objectives were to (i) identify riparian plant diversity along riverside-desert gradients in Tarim desert riparian forests, (ii) analyze the impact of environment variables on plant diversity, (iii) determine the optimum groundwater depth for different plant life-forms. Six transects 90 quadrats (with each size 100 m × 100 m) distributed vertically to river bed along riverside-desert gradients ~30 km in length were surveyed. At each quadrat, the morphological features of riparian plant communities were measured, and the groundwater depth, soil water, soil salinity, soil nutrient were also monitored at same sites. Three distinct vegetation communities were identified based on cover and richness in the tree, shrub and herb layers: the riparian zone, the transitional zone and the desert margin zone. Twelve species were indicators of the three vegetation communities. Riparian plant diversity was influenced by groundwater depth, distance from river, soil moisture content, soil salinity and soil nutrient by redundancy analysis. In response to groundwater depth, the optimal groundwater depths for species diversity, evenness and shrub cover were 2.8, 2.7 and 3.7 m, respectively. Therefore, maintaining high plant diversity requires managers to ensure stable groundwater depth for different plant life-forms rather than for some of them.

DIFFERENT POLLUTANT MONITORING IN QARUN LAKE

The presence of pollutants in the lakes considers the most common problem facing consumers. So, the aim of this study was to monitor the physiochemical, bacteriological properties of Qarun lake. It is a closed saline lake in the northern part of El-Fayoum Depression (Middle Egypt) at the margin of the Great Western Desert. During the 20th century, lake water salinity has increased strongly as a result of high evaporation rate. Also fish productivity decreased strongly. It receives agricultural and domestic non-treated drainage waters, which are also used for aquaculture in Qarun area. The study aimed to know the state of the lake and monitored the effect of agricultural drainages and domestic on the concentration of pollutants. The Physiochemical, bacteriological and some heavy metals monitored during the summer of 2017 to compare it with the previous results of the lake. The study proved that the lake suffering pollution by heavy metals as Cd (0.0034mg/l), Zn (1.091mg/l) at Al-Bats drain, NH3 (0.58 mg/l),PO4-3(1.38mg/l),COD (292mg/l) and BOD (71mg/l) at Al-Wadi drain. Therefore, it is necessary to put an environmental policy to control this pollution.