Journal Sciences News
The Saudi Dental Journal
July 2018
Editorial Board
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154

July 2018
How do young cacti (seeds and seedlings) from tropical xeric environments cope with extended drought periods?
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Arag
July 2018
Aquatic invertebrates increase litter breakdown in Neotropical shallow semi-arid lakes
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Renan de Souza Rezende, Jos
July 2018
Field and laboratory responses to drought by Common Side-blotched Lizards (Uta stansburiana)
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Peter A. Zani, Samantha J. Stein Starting in 2012, and peaking in 2013, drought conditions in the Great Basin Desert persisted for almost four years. By studying a meta-population of Common Side-blotched Lizards in the wild, we found that a failure of spring rains correlated with a marked reduction of body condition in female, but not male, lizards. Likewise, rainfall correlated with reproductive scores of females such that a failure of spring rains in 2013 resulted in a cessation of the breeding season. By 2014 it was apparent that the drought had caused a general failure of recruitment into the population, which affected the body-size distribution of lizards for several subsequent years. To disentangle the effects of both water and food availability during a drought, we next conducted a laboratory experiment by imposing a drought on breeding animals, but not otherwise limiting food. Results indicate that the absence of drinking water alone tends to delay the breeding season as well as cause reproductive failure in females even as body condition was maintained. Our combination of field and laboratory data reveal that body condition and reproductive responses to drought are not strictly about food limitations, but are also caused by a lack of available drinking water.
July 2018
Interactions among hydrological-aeolian processes and vegetation determine grain-size distribution of sediments in a semi-arid coppice dune (nebkha) system
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Junran Li, Sujith Ravi The formation of coppice dunes (nebkhas) has been attributed to both aeolian and hydrological processes, however, the interactions between these processes and vegetation dynamics are poorly understood. Additionally, a systematic study on the roles of dune geometry, morphology and hydrological processes in relation to sediment grain-size distribution in the coppice dune system is lacking. Here, we analyzed detailed grain-size distribution and saturated hydraulic conductivity for sediments collected from a series of coppice dunes with different morphological features and phases of development in a degraded shrubland in the southwestern US. Our results show that fine-grained dune sediments are associated with the wind-driven accumulation of very fine sand and fine sand (50–250
July 2018
Impacts of climate change and irrigation on lakes in arid northwest China
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Leqi Fang, Shengli Tao, Jiangling Zhu, Yu Liu Lakes provide valuable water resources for people, life, and socioeconomic development in Northwestern China---a core region of the arid Central Asia where water is seriously deficient. In this study, we report the first investigation of the 30-year changes in all lakes larger than 1
July 2018
Shrub cover and fire history predict seed bank composition in Great Basin shrublands
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Sarah Barga, Elizabeth A. Leger Dormant seeds in the soil are an important contribution to the regenerative potential of an area. Understanding factors that affect seed bank dynamics in arid regions provides insight into how communities respond to disturbance and environmental change. We characterized seed banks in a Great Basin sagebrush steppe system, using field surveys and seed bank studies to compare 17 sites that differed in above-ground vegetation, fire history, and grazing use. We asked whether shrub cover, ground cover, climate, or disturbance history were predictive of seed densities, diversity, the presence of rare species, and similarity between above- and below-ground communities. Fire frequency and a coarse measure of grazing use were not highly predictive of seed bank dynamics, with the exception that sites that burned <10 years ago had greater above-vs. below-ground similarity. Shrub cover predicted multiple below-ground characteristics: Ericameria nauseosa was associated with increased density of introduced species, Chrysothamus viscidiflorus was associated with increased densities of native annual species, and Artemisia tridentata was associated with increased richness of rare native species. Shrub cover estimates were predictive of seed bank composition, and suggest that areas dominated by A. tridentata would have the greatest restoration potential within their seed banks.
July 2018
Vegetation and seed banks of arid ephemeral gilgai wetlands subject to contrasting grazing regimes
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Richard J.-P. Davies, Duncan A. Mackay, Molly A. Whalen, Anita K. Smyth Ephemeral gilgai wetlands of the stony-plains of arid Australia have a relatively high diversity of native plant species and are extensively utilised for livestock grazing. We sampled the standing vegetation (SV) and germinable soil seed bank (SSB) of 40 gilgais, comparing gilgais near and far from watering points, and continually stocked versus rarely stocked. Despite historically heavy stock grazing, we found no significant differences in native species richness between treatments, indicating the general resilience of gilgai vegetation. One contributing factor is the abundance of Atriplex nummularia ssp. omissa. Cover of this long-lived shrub did not differ significantly between treatments and was positively correlated with “highly palatable” species’ cover, suggesting that it may act as a nurse species. In contrast, two other long-lived species, Atriplex vesicaria and Astrebla pectinata, had significantly reduced cover or were absent near to watering points. These and other long-lived species had a poorly developed SSB and thus limited ability to regenerate from seed if killed by sustained heavy grazing. The absence of fifteen locally rare species (including 12 short-lived species) from water-near gilgais indicates the need for more intensive survey to determine whether the proliferation of watering points poses a threat to such species.
July 2018
Communities of arbuscular mycorrhizal fungi associated with perennial grasses of different forage quality exposed to defoliation
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Mariela Lis Ambrosino, Marta Noem
July 2018
Seasonal interactions of pastoralists and wildlife in relation to pasture in an African savanna ecosystem
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Samantha Russell, Peter Tyrrell, David Western Wildlife and livestock have coexisted across East African rangelands for millennia, tracking seasonal forage availability across large landscapes. More recently however, free-ranging movements have been increasingly restricted by land use changes, reducing the ability of livestock and wildlife to access necessary grazing resources, leading to both homogenization and degradation of the rangeland. This in turn has led to losses in productivity of both livestock and wildlife. This study describes wildlife and livestock interactions in response to pasture in one of the few remaining areas of mixed wildlife-livestock use with unrestricted movements. We ask if pastoral management systems can create and maintain spatial and temporal heterogeneity of pasture, through the seasonal movement of livestock. Furthermore, does this heterogeneity create a diverse, productive and resilient assemblage of both domestic and wild ungulates? Our results provide evidence to support the notion that traditional pastoral systems which continue to manage for heterogeneity of pasture can still support not only livestock but also substantial numbers of wildlife. The results highlight the need for wildlife and livestock to retain both mobility and access to both wet and dry season areas to maintain ecosystem resilience and promote coexistence in mixed livestock-wildlife landscapes.
July 2018
Perennial warm-season grass monocultures and mixtures: Biomass production and soil improvement in semiarid and shallow soil conditions
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Silvia Susana Paredes, N
June 2018
The ‘Small Town Paradox’ and towns of the Eastern Cape Karoo, South Africa
Publication date: July 2018
Source:Journal of Arid Environments, Volume 154 Author(s): Danie Francois Toerien Some small towns regress whilst others grow, i.e. a 'Small Town Paradox' (STP). Differential accumulation of productive knowledge could possibly be its cause. Suggestions that small towns in the Eastern Cape (EC) Karoo, South Africa survive only as a result of a state welfare system suggest that the STP does not occur in this semi-arid region. Productive knowledge (measured as enterprise richness) and demographic shifts between 1946 and 2015 in EC Karoo towns were analysed. Whilst all populations increased, the productive knowledge of three small towns increased but that of five small towns regressed. The STP is present in the EC Karoo. The contrarian success of the three towns is apparently due to strength in two business sectors: agricultural products and services, and tourism and hospitality services. These sectors are important in generating monetary inflows into the local economies of EC Karoo towns. The successful small towns are innovatively using tourism resources available to them, including tourists on national routes, the attractions of wilderness areas and a national park, gay tourism, game farms and hunting. Productive knowledge seems to play a part but aridity not. Development plans of towns in arid and semi-arid environments could benefit from these findings.

Graphical abstract

image
June 2018
Editorial Board
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153

June 2018
Contrasting ecophysiology of two widespread arid zone tree species with differing access to water resources
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): Rachael H. Nolan, Tonantzin Tarin, Rizwana Rumman, James Cleverly, Kendal A. Fairweather, Sepideh Zolfaghar, Nadia S. Santini, Anthony P. O'Grady, Derek Eamus Arid environments can support the seemingly unlikely coexistence of species tolerant of, or sensitive to, dry soil moisture. Here, we examine water-use and carbon-gain traits in two widespread tree species in central Australia: Acacia aptaneura and Eucalyptus camaldulensis. The former has a shallow root distribution and relies on soil moisture, while the latter is groundwater dependent. We hypothesised that A. aptaneura would exhibit a suite of characteristics that confer tolerance to low soil moisture, in contrast to E. camaldulensis. Consistent with our hypotheses A. aptaneura was relatively more anisohydric than E. camaldulensis (seasonal leaf water potential of
June 2018
Patterns and determinants of the response of plant biomass to addition of nitrogen in semi-arid and alpine grasslands of China
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): Xiaotian Xu, Hongyan Liu, Wei Wang, Zhaoliang Song Although the effects of adding nitrogen (N) to grasslands have been studied worldwide, little is known about how those effects are, in turn, influenced by climate, soil, and vegetation. Data from such experiments conducted in two main types of grassland in China, alpine and semi-arid, which differed widely in terms of climate, soil, and vegetation, were compiled and analysed to examine the response of above-ground biomass to N. Adding N increased the above-ground biomass by 51% on average. Although the response of biomass showed no obvious trend with the dose of N in the alpine grasslands, the response in the semi-arid grassland peaked at 15–20
June 2018
Intraspecific leaf shape at local scale determines offspring characteristics
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): Estrella Pastor, Santiago Soliveres, Alberto Vilagrosa, Andreu Bonet Identifying the degree of adaptation to particular environmental constraints at small geographical scales (e.g., intra-population variability) is particularly valuable to select plant reproductive material in restoration projects. We analyzed possible differences among progeny characteristics of Quercus coccifera L. a species of interest in forest restoration under Mediterranean climates. The differences were tested among seeds and seedlings from two phenotypic groupings (small and large leaves) within one provenance under semi-arid climate. In addition, these seeds and seedlings were compared with those from a near population under contrasted climate (i.e., subhumid climate). We analyzed differences in germination, growth and seedling morphological traits (height, number of leaves and canopy area). We considered the different characteristics of the progeny across different parent individuals, intra- and inter-population levels. We found seed provenance effects on germination and seedling morphology at different scales. Progenies from semi-arid populations and from parent plants with a smaller leaf size showed lower germination rates and lower development of above-ground structures (shoots and leaves). Our results suggest that intrapopulation variability for phenotypic traits, such as leaf size, could influence offspring fitness. In addition, these morphological traits are easily identifiable by stakeholders and could be a useful tool to ensure early plant establishment in reforestation programs.
June 2018
The effects of habitat variables and land use on breeding birds in remnant wetland strips in an arid, rural landscape
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): F. Khoury, P. Korner The Jordan Valley exemplifies the pressure of multiple human actions including intensive livestock grazing and agriculture on bird diversity. The abundances and occurrence of breeding birds were studied along remnant perennial streams which flow into the River Jordan. A patch – landscape approach was used to study the influences of vegetation cover and disturbances at the local and landscape scales. For 21 species, Principal Component Analysis was used to reveal the importance of each spatial scale and relationships with habitat variables were modeled. The abundances and occurrences of 57% of the species were predicted by local habitat variables only, while most others were apparently influenced by a mixture of habitat and landscape factors. Birds with restricted distribution were associated with less degraded wetland habitat strips with heterogeneous vegetation including reed beds and inundated Tamarix thickets. Some species were negatively influenced by intensive grazing and the spread of invasive mesquite Prosopis juliflora. Most species appeared to be tolerant to low levels of grazing within the habitat and current land use in the surrounding landscape. Based on the results, we emphasize the importance of protecting and managing remnant strips or patches of natural and semi-natural wetland habitats in the Jordan Valley.
June 2018
Bush encroachment influences nocturnal rodent community and behaviour in a semi-arid grassland in Gujarat, India
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): Anisha Jayadevan, Shomen Mukherjee, Abi Tamim Vanak Bush encroachment is one of the major threats to grasslands globally. The increased cover due to bush encroachment can strongly influence the behaviour of animals adapted to a more open habitat. In this study, we explored the effects of bush encroachment on the foraging behaviour of nocturnal rodents the semi-arid Banni grasslands of western India, once one of India's largest tropical grassland habitats. We quantified foraging behaviour using the giving-up density (GUD) framework, across two sites that differed in the extent of bush encroachment. Rodents in the site with high bush encroachment (the dense site) exhibited higher foraging costs (higher GUD) in early summer compared to the site with low bush encroachment (the sparse site). Rodents in the dense site also had lower activity. The dense site supported higher richness and relative abundance of generalist rodents than the sparse site. Our results suggest that bush encroachment may be associated with higher foraging costs for nocturnal rodents and result in a change in species composition of rodents. Given the ecosystem engineering services performed by native grassland species, these results can have negative implications for grassland restoration.
June 2018
Formation of desert pavements and the interpretation of lithic-strewn landscapes of the central Sahara
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): Jasper Knight, Andrea Zerboni This study focuses on two different but interlinked lines of evidence that critically examine land surface processes contributing to the formation of desert pavements in the central Sahara. (1) Soil pedostratigraphies from the Messak plateau (SW Libya) illustrate phases of land surface stability and instability that reflect humid and arid phases of Quaternary climate, respectively. (2) The density and morphologies of surface lithic scatters in the same region were re-examined, based on data previously published by Foley and Lahr (2015, PLoS ONE). This re-examination shows that many surface clasts previously interpreted as lithics are better interpreted as formed by in situ weathering and wind abrasion. Furthermore, weathering, abrasion and deflation are the major processes by which desert clasts are formed and concentrated on the land surface, not human agency. Erosional Quaternary periods allowed for the formation of condensed pedostratigraphies by which surface clasts and lithics were mixed and concentrated on the land surface. These two independent lines of evidence show that desert land surfaces do not reflect a single time period of formation, and that Quaternary desert pavements (including any lithics located thereon) evolved in response to subaerial weathering and erosion processes.
June 2018
Land degradation and gully development in arid environments deduced by mezzo- and micro-scale 3-D quantification – The Negev Highlands as a case study
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): Rachel Zweig, Sagi Filin, Yoav Avni, Amir Sagy, Amit Mushkin We study in this paper land degradation processes in arid environments that are leading to a major environmental change. These processes, which are mostly the outcome of gully development, have direct impact on agriculture potential, biomass degradation, and escalating desertification. Three representative sites within the Negev Highland, Israel, are studied by utilizing terrestrial laser scans to gain detailed spatial information, accurate estimations, and concisely document overarching trends. The resulting information allows us to thoroughly characterize and quantify the geomorphic and vegetative changes and to calibrate rates and trends that have only been roughly estimated thus far. The scans, which were taken over a four-year span (2009–2013), cover three different types of hydrological seasons and provide unique insights on development rates and subsequent ramifications. The characteristic progression of natural land degradation in the Negev Highlands and the techniques used to document and analyze it can be extended globally to regions undergoing similar transitions.
June 2018
How reliable is the Walkley-Black method for analyzing carbon-poor, semi-arid soils in Ethiopia?
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): Tigist Araya Gessesse, Asia Khamzina Soil degradation in sub-Saharan Africa necessitates accurate soil carbon quantification using a locally applicable method. We assessed the reliability of the original Walkley-Black method for analyzing soil organic carbon (SOC) in semi-arid soils in northern Ethiopia characterized by low SOC (1.3
June 2018
Quantifying multi-scale pastoral mobility: Developing a metrics system and using GPS-Tracking data for evaluation
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): Chuan Liao Mobility appears to be in decline in modern pastoralism, but measurement of mobility has been ambiguous. This paper develops a metrics system to evaluate multi-scale pastoral mobility, and uses continuous, frequent, cross-season GPS-tracking data to investigate movement patterns in five pastoral communities in southern Ethiopia. The metrics system includes both broad-scale indicators such as home range and number of camps, and fine-scale indicators such as herding loop length, daily maximum distance from camp, and angular distribution of observed cow locations. The findings suggest pastoral mobility patterns are highly heterogeneous, and there are clear trade-offs among different mobility indicators in pastoralists’ herding strategies. In contrast to conventional understanding that mobility declines when pastoralists settle down, I find evidence of sedentarized pastoralists engaging in more rigorous fine-scale movement than those who keep practicing camp relocation. Thus, pastoral mobility cannot be generalized according to any single indicator, and comprehensive evaluation is necessary to advance our understanding of pastoral mobility as a complex strategy to manage herds in the arid and semi-arid environments.
June 2018
MODIS NDVI trends and fractional land cover change for improved assessments of vegetation degradation in Burkina Faso, West Africa
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): Benewinde J-B. Zoungrana, Christopher Conrad, Michael Thiel, Leonard K. Amekudzi, Evariste Dapola Da Reduction of natural vegetation cover in the savannah of West Africa constitutes a pressing environmental concern that may lead to soil degradation. With the aim to assess the degradation of natural vegetation in the savannah of Burkina Faso, this study combined NDVI trends and fractional Land Use/Cover Change (LULCC). Fractional LULCC maps, derived from the aggregation of a 30
May 2018
Identifying optimal remotely-sensed variables for ecosystem monitoring in Colorado Plateau drylands
Publication date: June 2018
Source:Journal of Arid Environments, Volume 153 Author(s): Travis B. Poitras, Miguel L. Villarreal, Eric K. Waller, Travis W. Nauman, Mark E. Miller, Michael C. Duniway Water-limited ecosystems often recover slowly following anthropogenic or natural disturbance. Multitemporal remote sensing can be used to monitor ecosystem recovery after disturbance; however, dryland vegetation cover can be challenging to accurately measure due to sparse cover and spectral confusion between soils and non-photosynthetic vegetation. With the goal of optimizing a monitoring approach for identifying both abrupt and gradual vegetation changes, we evaluated the ability of Landsat-derived spectral variables to characterize surface variability of vegetation cover and bare ground across a range of vegetation community types. Using three year composites of Landsat data, we modeled relationships between spectral information and field data collected at monitoring sites near Canyonlands National Park, UT. We also developed multiple regression models to assess improvement over single variables. We found that for all vegetation types, percent cover bare ground could be accurately modeled with single indices that included a combination of red and shortwave infrared bands, while near infrared-based vegetation indices like NDVI worked best for quantifying tree cover and total live vegetation cover in woodlands. We applied four models to characterize the spatial distribution of putative grassland ecological states across our study area, illustrating how this approach can be implemented to guide dryland ecosystem management.
May 2018
Editorial Board
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152

May 2018
Plant-microbe interactions as a cause of ring formation in Bouteloua gracilis
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): Lance Carlton, Nora C. Duncritts, Y. Anny Chung, Jennifer A. Rudgers Patterned vegetation growth such as grass rings is found in many arid ecosystems, yet the mechanisms behind their formation are often unknown and have been minimally tested in the field. One explanation is pathogen accumulation in the center of a long-lived plant, which could cause central dieback and the formation of a ring as the plant grows toward pathogen-free soil. We tested this mechanism by comparing the growth of blue grama grass (Bouteloua gracilis) in live and sterilized soils from inside or outside naturally occurring grass rings. Field-collected roots from the inner edge of grass rings had higher fungal colonization than roots from the outer edge, suggesting the potential for intensified pathogen interactions on the inside of rings. However, while plants grown in live soils performed worse than those in sterile soils, this pathogenic effect did not differ between soils collected from inside versus outside of grass rings. Further work on the spatial distribution of plant-microbe interactions is needed to confirm their direct role in ring formation. Our findings suggest that soil and root microbes, in addition to known mechanisms such as soil hydrology, potentially promote ring formation of a widespread North American grass species.
May 2018
An exploratory survey of long horn beetle damage on the dryland flagship tree species Boswellia papyrifera (Del.) Hochst
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): Aklilu Negussie, Kindeya Gebrehiwot, Mekonnen Yohannes, Ermias Aynekulu, Belay Manjur, Lindsey Norgrove Boswellia papyrifera (Del.) Hochst, a flagship tree species in the drylands of Ethiopia, is of high ecological, economic and social value. Recent work has shown that a wood-boring beetle is threatening its survival. In situ and ex situ studies were carried out to study the biology and damage associated with the insect in the dry lowlands of Northern Ethiopia. The beetle's life cycle, biology, and population were studied for 10 months. The mortality of B. papyrifera trees due to the wood-boring beetle was assessed in two land management systems (managed and unmanaged) in 64 (400
May 2018
Intraspecific leaf functional trait variability of eight Prosopis pallida tree populations along a climatic gradient of the dry forests of northern Peru
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): Pablo C. Salazar, Rafael M. Navarro-Cerrillo, Gast
May 2018
Can providing shade at water points help Kalahari birds beat the heat?
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): Salamatu Abdu, Andrew E. McKechnie, Alan T.K. Lee, Susan J. Cunningham Arid-zone birds trade-off dehydration and hyperthermia during hot weather, as they are dependent on evaporative cooling when air temperature approaches or exceeds body temperature. Water points in many arid ecosystems become surrounded by piospheres, exposing drinking birds to high radiant heat loads and exacerbating this trade-off. This challenge will be aggravated under climate warming. One possible mitigation approach is to reduce heat loads birds experience when seeking water. We experimentally shaded water points on farmland in the Kalahari. We used a Before–After Control–Impact design to assess the impact of artificial shade on species, visitation rates and visitation patterns of drinking birds. The number of species drinking was not affected by the introduction of shade, but overall visitation rates declined, despite a habituation period prior to data collection and increased use of shaded water points during the heat of the day. Of the ten most common species, one –the smallest species in the study - significantly increased and four significantly reduced visitation rates to experimentally shaded water points. Providing shade benefited few species overall, perhaps because of increased perceived predation risk. Future work should investigate the impacts of shader design in order to develop this method as a conservation tool.
May 2018
Matrilineal genealogies suggest a very low dispersal in desert rodent females
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): Eduardo Felipe Aguilera-Miller, Sergio Ticul
May 2018
Nitrogen addition decreased soil respiration and its components in a long-term fenced grassland on the Loess Plateau
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): Lin Wei, Jishuai Su, Guanghua Jing, Jie Zhao, Jian Liu, Jimin Cheng, Jingwei Jin Knowledge of the impact of N enrichment on soil respiration components is critical for understanding carbon (C) cycling and its feedback processes with climate change. We conducted three N level addition experiments, control (CK, 0
May 2018
Estimating groundwater contribution to transpiration using satellite-derived evapotranspiration estimates coupled with stable isotope analysis
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): S. Gokool, E.S. Riddell, A. Swemmer, J.B. Nippert, R. Raubenheimer, K.T. Chetty The relative importance of groundwater (GW) to sustain terrestrial vegetation has been well documented. However, quantifying GW use by riparian vegetation in data scarce regions may prove to be challenging. For this purpose, we coupled evapotranspiration (ET) estimates from the satellite-based surface energy balance system (SEBS) model with stable isotope analysis, to map and quantify the contribution of GW to transpiration (ET g ), along the lower reaches of a perennial river system, in the semi-arid north-eastern region of South Africa. Plant stem, soil, stream and GW samples were collected on 3 sampling occasions during the 2016 dry season.
May 2018
Climatic modulation of early summer dust emissions over West Africa
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): Mark R. Jury This study describes how climatic conditions affect of the generation and transport of dust over the SW Sahara Desert (12°-22°N, 18°W-20°E), with a focus on early summer in the period 1980–2014. Results are given for the annual cycle and climatology of May–Aug season, trends in aerosol optical depth (AOD) and contributing factors, co-variability of monthly and daily AOD and climate variables, case studies of dust generation in early summer and analysis of diurnal fluxes. The study is underpinned by multi-satellite measured AOD and ECMWF meteorological reanalysis fields. Linear trends in the period 1980–2014 indicate that AOD (dust) diminished slightly as rainfall and vegetation cover increased. Concommitant climatic trends include a weakening of Atlantic trade winds, acceleration of the easterly jet and inland penetration of the Guinea monsoon. Trends in temperature and winds strengthen above the boundary layer; suggesting that surface changes are damped by greening of the Sahel 1980–2014. Climatic conditions favoring dust emissions are evident in sensible heat flux, maximum temperature and upward motion at seasonal and daily time scales, with influence from wind vorticity at diurnal time scale. Incremental knowledge on climatic controls of dust mobilization could improve emission budgets and forecasts for the SW Sahara Desert.
May 2018
An experimental study to assess the effect of the energy and the electrolyte concentration of rain drops on the infiltration properties of naturally crusted soils
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): G. Carmi, I. Abudi, P. Berliner The main objective of the study was to assess the relative importance of the electrolyte concentration of rain drops and their kinetic energy on the infiltration rate of naturally crusted loess soil. A highly accurate portable rainfall simulator was used in this study. The effect of electrolyte concentration on infiltration rates was studied by comparing the runoff patterns observed using distilled or tap water. Similar infiltration curves were obtained for both treatments indicating that the effect of the electrolyte concentration of the applied water on infiltration was negligible. The effect of raindrop energy on infiltration rate was assessed by comparing the runoff characteristics of three treatments: fog, plot covered with dense mesh and no-surface protection. No runoff was observed in the fog treatment and the infiltration rates in the protected treatment were significantly higher than those of the unprotected treatment. The results of this study suggest that the momentum of drops hitting a naturally crusted loess soil significantly affect the infiltration process while the electrolyte concentration of the rain water does not meaningfully contribute to further crust development. Runoff coefficients derived from studies carried out with rainfall simulators that do not mimic the natural distribution of drop size and energy should be viewed with care.
May 2018
Vegetation's role in controlling long-term response of near ground air temperature to precipitation change in a semi-arid region
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): Yu Hui, Quan Zhang, Chong-Yu Xu, Lihua Xiong, Jie Chen, Ping Xie The response of near ground air temperature to changing precipitation regimes has received extensive attentions in climate change studies. In semi-arid and arid regions, the mean annual temperature correlates negatively with precipitation. However, it remains unclear to what extent one unit change of precipitation can trigger temperature change (i.e., the temperature sensitivity to precipitation). Taking a semi-arid region in Northwest China as a study area, we quantitatively investigated the temperature sensitivity to precipitation change. Further analysis shows that the temperature sensitivity correlates well with the Normalized Difference Vegetation Index (NDVI), indicating that vegetation plays an important role in controlling the long-term temperature sensitivity to precipitation change. Specifically, different land covers show significant differences in temperature sensitivity, with bare soil generally having a higher sensitivity while more densely vegetated areas such as forest and grassland having lower sensitivity values. This implies that vegetation contributes to reducing the temperature sensitivity to precipitation change through the land surface-atmosphere interaction in semi-arid and arid regions.
May 2018
On resource defense and sustainable grazing: Forage use by territorial and non-territorial guanaco groups
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): Andrea Marino, Victoria Rodr
Available online 26 April 2018
Smallholder farmer perceived effects of climate change on agricultural productivity and adaptation strategies
Publication date: May 2018
Source:Journal of Arid Environments, Volume 152 Author(s): Veronica Makuvaro, Sue Walker, Tirivashe Phillip Masere, John Dimes The agriculture sector is sensitive to climate change and the capacity of smallholder farmers in developing countries to adapt is limited. Similar to adoption of any development-oriented strategies, perception is pre-requisite to successful adaptation of agricultural strategies against climate change effects. This study was conducted in the semi-arid Lower Gweru Communal area of Central Zimbabwe to sensitize smallholder farmers on climate change and to establish their perceptions of the projected climate of Zimbabwe by 2050. Data were collected during 2011 from a total of 60 farmers drawn from six villages in Mdubiwa and Nyama Wards. Farmers were selected using systematic random sampling from a households list and grouped into three wealth groups: resource rich; resource poor and intermediate. Focus Group Discussions were conducted with each group to investigate their perceptions of the projected climate by 2050 and their proposed adaptive strategies. Farmers perceived the projected climate to have negative effects on their livelihoods and there were no outstanding differences in the nature of responses across the three categories of farmers. Farmers’ responses showed that they were concerned about crop and livestock productivity as well as availability of water resources, food and nutrition security and about their general well-being. The intermediate wealth group, which had more than half of its members above 70 years of age provided the least number of ideas for adaptations. Farmers also suggested how they could possibly counteract some of the predicted negative effects or maximize on positive effects. Strategies that were suggested by the farmers were largely concerned with cropping and tended to address water shortages. It was concluded that almost all strategies suggested by farmers were self-directed, rather than directed at authorities like government or donors to do something for them thus showing that farmers had the will power to deal with climate change themselves.
Available online 23 April 2018
Mapping regulating services in Marrakesh Safi region - Morocco
Publication date: Available online 26 April 2018
Source:Journal of Arid Environments Author(s): Houda Ghazi, Mohammed Messouli, Mohammed Yacoubi Khebiza, Benis N. Egoh Mapping ecosystem services (ES) has become an important tool to study nature's contributions to people (NCP) spatially and to manage ecosystems sustainably. However, few of these studies have been carried out in Africa and even fewer in drylands. This is not surprising, as drylands in general have not received much attention in the field of ecosystem services due to the perception that they do not provide much due to their low levels of productivity. In addition, not much data is available to map ecosystem services in Africa. In this study, we map regulating services of the Marrakesh Safi region in Morocco. First, a land cover map was developed based on existing information. This land cover map was thereafter used to map and model three regulating service categories in the region namely, carbon sequestration, microclimate regulation, and hydrological services (water regulation and water quantity) using six indicators. Our results show that agricultural land, which occupies the largest percentage area, also sequestered the most carbon in the study area. Forests sequestered about 16% carbon despite occurring in only 14% of the area and are the most efficient in sequestering carbon when considering carbon sequestered per hectare per year. The ecosystem type with the highest potential to supply water regulation services was Quercus ilex with about 200 m3/ha. The study shows that the hotspots areas are located in the southeast parts of the study area where the Quercus ilex is mostly found. Contrary to the belief that most arid systems are not productive and therefore do not provide many ecosystem services, our spatial outputs showed that the area around Marrakesh in Morocco, despite being arid provides many regulating services including water and microclimate regulation.
Available online 17 April 2018
Beta diversity of ant-plant interactions over day-night periods and plant physiognomies in a semiarid environment
Publication date: Available online 23 April 2018
Source:Journal of Arid Environments Author(s): Pedro Luna, Yasmira Pe
Available online 16 April 2018
Spatial variations in plant nutrient concentrations in tissue of a grass species as influenced by grazing intensity in a confined savannah rangeland
Publication date: Available online 17 April 2018
Source:Journal of Arid Environments Author(s): C. Munyati Grazing can influence spatial variations in grass tissue concentrations of plant nutrients by promoting nutrient recycling through grazer dung. This study demonstrates the acuteness of the spatial variations, in a confined semiarid savannah rangeland where grazer migration has been curtailed. Eragrostis lehmanniana, a commonly grazed grass species, was selected for the study due to its abundance. Grass tissue and soil samples were collected at widely distributed sampling sites. The sample concentrations of macronutrients (N, P, K, Ca, Mg) and the micronutrients Fe, Zn, Mn, Cu, Ni, B, Mo were determined in the laboratory. Geostatistical analysis, spatial interpolation, factor analysis and Normalised Difference Vegetation Index values from a satellite image enabled assessment of spatial patterns in relation to grazing intensity. A grazing intensity induced zone of high nutrient concentrations in E. lehmanniana tissue was evident, in the vicinity of artificial water holes. Wide zones (1–2.8
April 2018
Creation of bunchgrass, sagebrush, and perennial grassland habitats within a semi-arid agricultural setting: Implications for small mammals
Publication date: Available online 16 April 2018
Source:Journal of Arid Environments Author(s): Thomas P. Sullivan, Druscilla S. Sullivan Native habitats of the semi-arid intermontane grasslands and shrub-steppe rangelands of the Pacific Northwest of North America are disappearing owing to agricultural, urban, and recreational development. A major small mammal occupying these habitats is the montane vole (Microtus montanus), along with the deer mouse (Peromyscus maniculatus), northwestern chipmunk (Neotamias amoenus), house mouse (Mus musculus), and two less common species at risk. To help restore these native habitats and small mammals, we tested three hypotheses (H) that non-crop habitats of native bunchgrasses, sagebrush (Artemisia tridentata), and perennial grasslands (alfalfa and mix of forage grasses) would: (H1) establish in an agricultural setting, (H2) conserve small mammal species, and (H3) limit vole damage to tree fruit production in orchards. Linear habitats of these non-crop treatments, within a semi-arid agrarian setting in south-central British Columbia, Canada, were sampled for all vascular plants and small mammals from 2006 to 2010. Mean abundance of bunchgrasses declined after the second year owing to competition from orchard herbs, but sagebrush and pasture grasses became well established, thereby partially supporting H1. Alfalfa established initially but then declined potentially owing to consumption by voles. Conservation of the three major small mammal species, but not less common species, partially supported H2. Alfalfa and pasture grasses provided optimum habitat for montane voles, but their high numbers did not result in feeding damage to tree fruit production, thereby supporting H3. Creation of non-crop habitats within as well as adjacent to agricultural settings should become a major endeavour to restore native habitats, enhance small mammal populations, and maintain biodiversity.
April 2018
Editorial Board
Publication date: April 2018
Source:Journal of Arid Environments, Volume 151

April 2018
Economic and environmental rehabilitation through soil and water conservation, the case of Tigray in northern Ethiopia
Publication date: April 2018
Source:Journal of Arid Environments, Volume 151 Author(s): Gebremedhin Gebremeskel, T.G. Gebremicael, Abbadi Girmay The natural resources in the semi-arid area of Tigray, northern Ethiopia, have been exploited for years. This has caused severe land degradation, which in turn led to recurrent drought and poverty. To recover the degraded lands, soil and water conservation (SWC) interventions were given a policy attention since the 1970s. Starting 1990s, SWC-based integrated catchment management (ICM) implementation programmes, complemented by conservation-based agricultural development strategy, have been implemented. Many studies on ICM interventions and associated benefits have been reported so far. However, as most of the studies were conducted on experimental plots/small catchment scale, none of them have attempted to report the achievements and lessons at large scale. Hence, a comprehensive review is needed to explore and publicize the interventions and associated benefits. This review was conducted through detailed analysis of evidence and facts from literature, field observations and farmers’ perceptions. The reviewed literature explicitly showed that ICM interventions have been successful in Tigray. Collective evidence has shown that most of the degraded landscapes are considerably restored, of which the soil fertility, availability of water, and rainfed and irrigated crop productivity have significantly increased over the last two decades. Consequently, environmental, ecological and socio-economic changes have been observed when compared to pre-implementation of ICM. Despite these achievements, some interventions often suffer from over-ambition, upward accountability and a top-down approach. Failures of Horeye and roof water harvesting, mismanagement of fertilisers, low survival of tree seedlings and lack of income from exclosures can be considered pitfalls that may affect the sustainability of the achievements. An important lesson drawn from Tigray is the participation of all stakeholders and the strong commitment and sense of ownership by the people and local government, which many projects lack worldwide. Observed experiences, achievements and implementation pitfalls can provide a lesson to other regions with similar agro-ecological, environmental and socio-economic setups.
April 2018
Factors affecting biodiversity in agrosylvopastoral ecosystems with in the Mediterranean Basin: A systematic review
Publication date: April 2018
Source:Journal of Arid Environments, Volume 151 Author(s): Sofia Plexida, Alexandra Solomou, Kostas Poirazidis, Athanasios Sfougaris The biodiversity of Mediterranean agrosylvopastoral ecosystems has been extensively studied, because the Mediterranean Basin is a crossroad of biogeographical influences between cold temperate biota and subtropical species. Here, we systematically reviewed biodiversity studies published on natural and managed agrosylvopastoral ecosystems between 2000 and 2013 to obtain information on animal and plant species richness and diversity and the factors that affect biodiversity. Overall, 774 studies of potential relevance were identified, of which 230 provided information on biological monitoring and 154 met the requirements for the systematic review. Most articles were published in 2004, 2007, and 2011, and most were conducted in Spain. There was sufficient data on species richness to perform a meta-analysis comparing the species richness of 18 different terrestrial ecosystems containing seven taxonomic groups: plants, birds, invertebrates, reptiles, fungi, mammals, and amphibians. Ecosystem type, experimental design, number of study sites, habitat characteristics, and landscape structure were the most frequently mentioned factors affecting biodiversity. Plants were primarily analyzed (42.9% of reviewed studies), with patches and plots being the most common experimental design (64.8%). In comparison, amphibians were the least studied group (1.7%), with transects being the least used experimental design (11.1%). Plants had the highest average species richness (128.25) in managed woodlands, while birds had the lowest (18), with invertebrates generally representing good indicators of biodiversity. Overall, our review indicates that habitat heterogeneity is of importance for safeguarding species adapted to the variety of microhabitats, with it being important to implement traditional cultivation and grazing practices when managing these areas (such as the maintenance of the agro-forestry systems).

Graphical abstract

image
April 2018
Transforming tradition: The aflaj and changing role of traditional knowledge systems for collective water management
Publication date: April 2018
Source:Journal of Arid Environments, Volume 151 Author(s): Grace Remmington Living in a harsh, desert climate, Omani rural communities have developed locally-appropriate knowledge to deal with water scarcity. Similar to the qanat, the aflaj taps into the natural water table and uses a gravity system to channel water through underground channels to villages. Traditional techniques of water management, such as the aflaj, represents a way of adapting to and coping with difficult climates which have persisted for millennia. However, knowledge systems have often ‘decayed’ with the onset of modernity. These management systems, which developed concurrently with early Omani date palm cultivation, have defined customary and hereditary water rights which are in decline. This article uses Ostrom's Common Pool Resource (CPR) framework, which prioritises the collective management of shared resources to maximise the benefit for all involved and avoid diminishing benefits that are created by the pursuit of individual goals. Using this framework, this article's evaluation of the literature found that traditional aflaj management systems have a great capacity to evolve and, therefore, the aflaj represents both a dying system, and a potential for climate adaptation. Historically, aflaj have been managed by ancient water users associations, which provide social controls and govern usage norms. The findings of this review are that the aflaj system's ability to respond to pressures of modernity from competing institutions, including markets, and embedded social capital mechanisms will influence its capacity to mitigate uncertain hydrology and climate. This article suggests ways in which the management of the aflaj can adapt to a multiple institutional framework to ‘transform’ collective water management.
April 2018
Phytotoxic effects of volatile and water soluble chemicals of Artemisia herba-alba
Publication date: April 2018
Source:Journal of Arid Environments, Volume 151 Author(s): Antonio I. Arroyo, Yolanda Pueyo, Fran
April 2018
Effects of nurse plants and the granivore guild in the associational susceptibility of seeds from the columnar cactus Pilosocereus leucocephalus
Publication date: April 2018
Source:Journal of Arid Environments, Volume 151 Author(s): Antonio Miranda-J
April 2018
Animal generation of green leaf litter in an arid shrubland enhances decomposition by altering litter quality and location
Publication date: April 2018
Source:Journal of Arid Environments, Volume 151 Author(s): Jane G. Smith, Heather L. Throop Soil carbon (C) and nutrients are derived largely from decomposition of plant biomass. Animals that generate greenfall, or green leaf litter, influence C and nutrient cycling dynamics by altering the phenological condition, and therefore nutrient quality, of plant litter entering the soil, and transporting litter among microsites. Microsite effects on decomposition rates are particularly pronounced in arid and semi-arid ecosystems where vegetation cover is often patchy. We investigated differences in decomposition of greenfall and senesced litter of three common Chihuahuan Desert plants from which animals frequently generate greenfall. A litterbag study was used to quantify differences in mass, C, and nitrogen (N) losses between green and senesced leaves in shrub intercanopy and subcanopy microsites in desert shrublands. We found significant differences in nutrient concentration of green and senesced leaves, and that both litter condition (green or senesced) and microsite affected decomposition rate. For two of the three litter species, greenfall decomposed more rapidly than senesced litter; for all three species, litter decomposed more rapidly in intercanopy than subcanopy microsites. These results support the idea that creation and translocation of greenfall by animals are important mechanisms regulating decomposition speed and C and nutrient transfer from plant biomass into the soil.
April 2018
Patterns of alpha diversity among Tunisian lizards (Lacertidae)
Publication date: April 2018
Source:Journal of Arid Environments, Volume 151 Author(s): Daniel Escoriza Reptiles are a successful group in subtropical arid regions. However, little is known about the drivers that influence the diversity of arid reptile communities. One approach is to investigate the variation in phylogenetic structure of the communities along a broad environmental gradient. In this study, I investigated these patterns in the communities of lacertids at the periphery of the Sahara Desert in Tunisia. The effect of the environment was assessed based on a set of variables describing the climate, topography, substrate and cover of perennial vegetation. The phylogenetic alpha diversity was described using the mean pairwise distance (MPD) and the mean nearest taxon distance (NTD) metrics. The analyses showed that the lacertid species could be clustered into three main ecological groups: mesic (Podarcis vaucheri, Psammodromus algirus, Psammodromus blanci, Timon pater), xeric (Acanthodactylus blanci, Acanthodactylus boskianus, Acanthodactylus maculatus, Mesalina olivieri, Ophisops occidentalis), and hyperxeric (Acanthodactylus dumerilii, Acanthodactylus longipes, Acanthodactylus scutellatus, Mesalina guttulata). The analyses also indicated that environment had a weak influence on species richness (15.7% of explained variance), but a strong effect on the phylogenetic (76.5% NTD, 89.5% MPD) structure. The lacertid communities tended to be phylogenetically clustered on sandy substrates under arid climate conditions, and overdispersed under more humid climatic conditions.

Going the distance on kangaroos and water: A review and test of artificial water point closures in Australia
Publication date: April 2018
Source:Journal of Arid Environments, Volume 151 Author(s): Tyrone H. Lavery, Anthony R. Pople, Hamish I. McCallum Grazing by overabundant herbivores can cause land degradation and reduce biological diversity. Across arid and semi-arid Australia, predator control, pasture improvement, and artificial water points (AWP) have contributed to increased populations of kangaroos and wallaroos (Macropus spp.). Control efforts (e.g. culling, predator reintroduction, fertility control) can be expensive, controversial and/or unsustainable in the long term. Closure of AWP is an alternative. We reviewed closures in Australia and found experimental tests have been few, and results unconvincing for two main reasons. Firstly, no study has tested AWP closures over distances influential to kangaroos. We identified seven AWP closure experiments in Australia. Five did not generate areas beyond 5 km from water and two used a method ineffective for excluding kangaroos. Secondly, post-closure monitoring has frequently been too short to detect changes amongst natural environmental fluctuations. Our own experimental AWP closure did not influence kangaroo populations and reaffirmed that kangaroo densities are dictated by food availability in Australia's water rich rangelands. Larger experiments are needed with systematic AWP closures that generate water remote landscapes, preferably exceeding 10 km from water. Monitoring must span dry, hot periods of below average rainfall when kangaroos are most likely dependent on drinking water.

Graphical abstract

image

view: 226

Get a Google Home When You Buy Two or More Qualifying Appliances Totaling $1,499 or More

Start: 01 Nov 2017 | End: 18 Nov 2018

100% Anniversary of the Chore Coat at Carhartt

Start: 28 Aug 2017 | End: 01 Mar 2018

Great hera! Check out our Wonder Woman merch here!

Start: 17 Jul 2017 | End: 31 Jan 2018

Search All Amazon* UK* DE* FR* JP* CA* CN* IT* ES* IN* BR* MX
Booking.com B.V. is based in Amsterdam in the Netherlands. Ready for some statistics? Our 1,534,024 properties, including 860,482 holiday rentals, are located in 123,105 destinations in 229 countries and territories, and are supported internationally by 198 offices in 70 countries.
2013 Copyright © Techhap.com Mobile version 2015 | PeterLife & company
Skimlinks helps publishers monetize editorial content through automated affiliate links for products.
Terms of use Link at is mandatory if site materials are using fully or particulary.
Were treated to the site administrator, a cup of coffee *https://paypal.me/peterlife
Yandex.ru