The Hedendoa of Sudan produce goat-hair blankets, called shamlas, for nuptial ceremonies employing an extremely rare and labour-intensive half-weaving technique that is completely unrelated to the narrow braided sewn strips used to produce palm leaf mats that cover their tents. I hypothesize that this technique exemplifies technological transfer resultant from casual encounters and incomplete observations of the weaving techniques of the Bedouin pastoral nomads of the region.
Desert ecosystems are extremely arid and nutrient poor. “Fertile islands” formed by mobile sand dunes and perennial desert plants are crucial for maintaining the structure and function of these ecosystems. However, the impacts of fertile islands created by different plant species at various spatial locations on soil physicochemical properties such as soil nutrients remain unclear. This study focused on the legumes (Astragalus flexus Fisch.), and non-legume (Eremurus inderiensis (M. Bieb.) Regel) plants widely distributed in the Gurbantunggut Desert in northwestern China. We analyzed the soil physicochemical properties of fertile islands formed by these two desert plants at different horizontal distances (0–140 cm) and vertical depths (0–15 cm). In addition, we investigated the relationship between plant functional shape and soil physicochemical properties. This study yielded the following results. (1) The fertile island was observed within the 0–140 cm soil layer of Astragalus flexus and Eremurus inderiensis and gradually weakened with increasing horizontal distance and soil depth. (2) The two plants had different nutrient enrichment rates. Eremurus inderiensis had higher TP and AK enrichment rates than Astragalus flexus. In contrast, Astragalus flexus demonstrated significantly higher enrichment rates for TN, NH4+-N, and NO3−-N, especially NH4+-N, highlighting the ability of legumes to fix and uptake N. (3) The correlation between plant height, crown width, and soil nutrient enrichment rate was more significant for Eremurus inderiensis than for Astragalus flexus. In general, both plants formed the fertile islands that gradually decreased with the increasing distance (both horizontal and vertical). Different plants exhibited varying abilities to enrich soil nutrients and form fertile islands, which presented a clear species effect. Therefore, protecting the diversity of desert plants to form stable fertile islands could be crucial for maintaining the soil fertility in desert ecosystems.
The current water crisis in the Atacama Desert is explained by extractivist models based on the overexploitation of this resource. Extensive mega-mining is devastating water reserves and causing inequities in access for local indigenous communities. In the present work, through ethnographic research in the community of Mamiña, we show how the water values of different local actors come into conflict. Through a positioned analysis model, we observe two types of water-related values, some determined by worldviews and others created by socio-environmental relationships throughout history. Along these two axes, we observe the emergence of new pragmatic values that make an adequate collective response to the water crisis challenging to implement. We argue that this paradox can be better understood through an approach focused on the sociocultural analysis of water values, deriving from the context of their emergence, as well as their complementarities and dynamics.
Drought events have significant impact on ecosystems and the livelihoods of rural communities in Iran. So, the purpose of this study was the analysis and evaluation of dimensions of adaptive capacity (AC) against drought in Bajestan county, Khorasan Razavi province, Iran. A questionnaire was used to collect data for social network analysis (SNA) and AC by the full network method. Then, a combined SNA-SEM model was developed to determine what was the social response of rangeland users in dealing with drought. In this study, the AC of rangeland users was compared in two groups of villages covered by the collaborative management or Carbon Sequestration Project (CSP) and uncovered by CSP. The results confirmed that the villages under CSP had higher levels of AC and social capital. Among five capitals, indicators of economic resources and information, skills and management were more effective on AC. Among the SNA indexes, effsize, constrain, indirects, density and betweenes centrality are more effective on AC of rangeland users. Results showed that identifying the key actors, who have the power and influence to determine the information flow and financial inflows in these components, can help increase the AC of rangeland users to mitigate effects of drought.
The current study focuses on large geometric flint sickle blades found in association with the deceased unearthed during the excavation of the Iron Age cemetery of Tel Erani. The archaeological meaning and interpretation of such a correlation are examined here through the prism of the system of burials and beliefs of Iron Age communities in the southern Levant and previous periods, where sickles and sickle blades were found in funerary contexts. Flint tools in the southern Levant may be divided into belonging to the deceased and used in life, and those serving as offerings to the dead by the community. The presence of sickles and flint sickle blades in burials of the southern Levant from the Chalcolithic period to the Iron Age may be interpreted as part of a ritual symbolizing a relationship between the deceased and agriculture. A concluding interpretation of these findings is presented here based on anthropological and archaeological parallels.
Solar energy development causes land-use change and habitat alteration that may affect desert ecosystems. Tenebrionid beetles have evolved to exploit desert environments and heavily contribute to ecosystem functionality in aridlands, yet their species-specific, ecological responses to solar energy development are unknown. Our objective was to elucidate effects of solar energy development decisions at a solar power facility (392 MW) on a tenebrionid beetle community in the Mojave Desert. Seven years post-construction, we used pitfall traps to collect tenebrionid beetles for one month in treatments representing variably intense site preparation practices and conservation measures, including blading (i.e., bulldozing), mowing, and establishment of undeveloped patches in solar fields, replicated across three power blocks comprising the facility and in undeveloped control sites surrounding the facility. Blading caused significant, deleterious effects on tenebrionid beetle abundance, species richness, and diversity. Ordination revealed apparent overlap of non-bladed treatments and controls, suggesting that intermediate levels of disturbance from less intensive solar energy development decisions may serve to minimize negative effects of solar energy development on tenebrionid communities. Anepsius delicatulus and Triorophus laevis, the two most commonly collected tenebrionids, were significantly more abundant in non-bladed treatments in the solar facility than in undeveloped controls; thus, solar facilities with minimized disturbance to vegetation may provide preferred habitat for certain tenebrionid species. Our results demonstrate the value of understanding variable responses of insects to solar energy development decisions in deserts to inform real-world adaptive management of natural resources during the renewable energy transition.
Woody plant encroachment degrades the economic and environmental potential of drylands by altering processes such as nutrient fluxes, ecohydrology, and ecosystem services. Though past research has investigated the encroachment process, relatively little is known about post-encroachment shrub community ecology. To better quantify dynamics within post-woody encroachment shrub communities, we combined USGS lidar height data and multispectral imagery to estimate shrub density, shrub height, shrub cover, and shrub volume across the Jornada Basin Long Term Ecological Research (JRN-LTER) site in southern New Mexico, USA. Structural estimates were analyzed in search of telltale signs of community competition, specifically, the presence of thinning relationships. Results demonstrated density-dependent thinning relationships in shrub communities of creosote and mesquite, indicating a large role for competition in arid shrub communities even at relatively low shrub densities and cover (∼35% cover). In addition, shrub volume estimates better modeled the expected thinning dynamics of shrub communities than shrub canopy cover measurements. Overall, our results indicate the utility of lidar data in extending two-dimensional descriptions of woody vegetation structure (i.e., woody canopy cover) into the critical third dimension (i.e., woody plant volume), as well as the relative importance of competition and demographic bottlenecks to vegetation structure in drylands.
Understanding human impacts on drylands is crucial in a global scenario of forest degradation and biodiversity loss. This study analyzed foliar concentrations of nitrogen (N) and phosphorous (P) in the Brazilian seasonally dry tropical forests (Caatinga). Foliar patterns of N, P, and the N/P ratio were assessed both within and among botanical families. To do this, 10 plots were established in an anthropized area and 10 in a conserved area. Within each plot, leaves from all tree species and soil samples from four random points were collected. Stoichiometric analyses were performed on the leaves of 136 trees from 14 botanical families. Significant differences were observed in soil P concentrations, organic matter content, and cation exchange capacity, with the highest values found in the conserved area. Foliar N and P concentrations and N/P were also higher in the conserved area for the F+ (nitrogen-fixing Fabaceae), F- (non-nitrogen-fixing Fabaceae), and NF (non-Fabaceae) groups, indicating greater efficiency in nutrient retention and cycling. When comparing species found in both areas, Aspidosperma pyrifolium (NF), Bauhinia forficata (F-), and Mimosa ophthalmocentra (F+) showed significant differences in foliar N concentrations and foliar P (for A. pyrifolium and B. forficata only). Degradation of the Caatinga directly impacts nutrient cycling.
The Zagros region in western Iran has experienced prolonged drought, significantly impacting water resource and forest ecosystems over the past few centuries. Understanding historical prolonged drought is crucial for making precise forecasts of shifts in regional drought in the Zagros region. Due to the lack of comprehensive historical records, the use of proxy records is considered a valuable tool for reconstructing past drought variations. We aimed to construct a tree-ring chronology of Juniper (Juniperus polycarpus) in the central Zagros region to comprehend its growth response to climate variables. We cored 25 J. polycarpus trees from the Keygooran forest reserve in western Iran and developed the tree ring chronology (1802–2022) using dplR. The relationships between tree growth and climate variables of monthly mean temperature, precipitation, PDSI (Palmer Drought Severity Index), and SPEI (Standardized Precipitation Evapotranspiration Index) were examined. The analysis revealed a strong positive correlation between tree growth and SPEI March-September of 1990–2018 on a 48-month timescale with a 2-year lag (r = 0.61, p < 0.05) which was included in the transfer model. Consequently, the SPEI-48 March-September was reconstructed for the period 1802–2022. On this reconstruction, several extremely dry years in 1832, 1867, and 1876 and extremely wet years in 1807, 1814, 1838, 1850, 1907, and 1908 years were identified, some of them aligning with historical records in Iran. Furthermore, there was a relationship between SPEI-48 March-September and teleconnection events suggesting that certain drought occurrences in the area were associated with the El Niño-Southern Oscillation (ENSO). Consequently, this reconstruction can serve as a reliable proxy for large-scale drought variability in the Zagros region of western Iran. Moreover, our research underscores the utility of SPEI in reconstructing the history of semi-arid climate conditions.
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