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Aims Sand-fixing shrub Salix gordejevii plays an important role in sand dune stabilization but often shows severe decline and mortality on the windward slopes of active dunes. The objective of this study was to explore the environmental drivers and physiological mechanisms behind its decline and mortality on the windward slopes of active sand dunes. Methods The xylem hydraulics, sap flow, water relations and non-structural carbohydrate reserves were measured for S . gordejevii plants that respectively inhabited interdune, leeward and windward positions of active dunes with contrasting soil water regimes. Results Root exposure caused by wind erosion, rather than low soil moisture, predisposed windward S . gordejevii plants to stronger water stress. Correspondingly, the windward plants showed reduced transpirational water use and exhibited a suite of acclimative adjustments in leaf traits favoring water conservation. Despite these adjustments, windward S . gordejevii plants still suffered from higher risks of hydraulic failure and branch mortality. No evidence of carbon depletion in windward S. gordejevii plants was found although the soluble sugar to starch ratios changed significantly. Conclusions Our findings suggest that wind-erosion-induced root exposure triggers water stress and eventually causes the mortality of windward S . gordejevii plants, during which increased risk of hydraulic dysfunction is pronounced.

Background Understanding the dynamics of species and functional diversity and their interrelationships during vegetation restoration is essential for assessing the effectiveness of ecosystem restoration. Yet, the mechanistic links between species diversity and functional diversity during vegetation restoration remain uncertain, with community-level functional traits likely mediating this relationship. Methods We studied a chronosequence of Artemisia ordosica -dominated dryland communities, including semi-fixed (D1), fixed (D2), soil-biocrusted fixed (D3), and shrub-herbaceous-fixed sand-dunes (D4). Thirteen leaf functional traits were measured, including leaf tissue density (LTD), and leaf dry matter content (LDMC). Community-weighted mean leaf functional traits (CWM-LFTs) were calculated using importance value-weighted averages. Results Species and functional diversity increased progressively from stages D1 to D4, with the coefficient of variation for CWM-LFTs ranging from 7.71% to 57.27%. Changes in species diversity during sand dune stabilization were linked to a strategy of slow growth and cumulative increases in LTD, LDMC, and leaf carbon content (LCC), improving the community’s physical defense and nutrient retention. Leaf structural traits mirrored diversity patterns, with LDMC most strongly linked to functional evenness, functional divergence and Rao’s quadratic entropy. Conclusions Our results show that both species and functional diversity increased progressively with sand-dune stabilization. The plant community followed a trajectory of increasingly complex strategies, shifting from stress-tolerant traits toward competition-adapted traits in later stages. The LDMC was strongly correlated with both species and functional diversity, serving as a key trait that mediates competitiveness and defense in resource-limited ecosystems. These findings highlight the importance of trait-based assembly in vegetation restoration and offer new insights for desertification control.

The increasing need for efficient and sustainable construction materials has prompted the investigation of local and recycled resources to improve the characteristics of poor soils. This research aims to enhance dune sand (DS)—a plentiful yet geotechnically weak material—by integrating rubber crumb (RC) and brick powder (BP), with the objectives of soil stability and waste valorization. Experimental formulations were created with RC at concentrations of 10%, 30%, and 50%, and BP at concentrations of 1%, 2%, and 3%. A response surface methodology (RSM) and artificial neural network (ANN) techniques were utilized to examine the influences of RC and BP content on three primary responses: maximum dry density (MDD), internal friction angle (ϕ), and cohesion (C). Ideal conditions with 40.7% RC and 3% BP were achieved through optimization utilizing RSM and ANN-GA, greatly enhancing compaction and shear strength for geotechnical applications. According to Life Cycle Assessment (LCA), a high CR content raises energy consumption (E-Energy) and greenhouse gas emissions (E-CO₂), primarily as a result of rubber recycling. However, the reduction in sand mining and the diversion of tyre waste balance these effects. Therefore, the combination of RC with BP is turning out to be a viable and efficient infrastructure solution, especially in dry regions.

This study focused on evaluating dune sand stabilized with lime and volcanic ash as base course materials in engineering construction. Dune sands are found in Saudi Arabia in huge quantities. Due to the high demand for construction materials, this makes them highly suitable for construction. A testing program was designed to investigate the effect of adding different percentages by weight of lime (L: 0, 2, 4, and 6%) and volcanic ash (VA: 0, 1, 3, and 5%) on the engineering properties of the stabilized mixture. Unconfined compressive strength (UCS) and California bearing ratio (CBR) tests were conducted. In addition, Raman spectroscopy and laser-scanning microscopy (LSM) tests were performed to explore the chemical characteristic, packing, and structure of the mixture. The results showed that the UCS, CBR, and the Young’s modulus (Es) of the treated dune sand increased with the increase in percentage of both stabilizers. Furthermore, LSM images of mortar blended with intermediate L-to-VA blend ratio ≈0.55 (L: 6% and VA: 5%) exhibit compact packing of sand grains, indicating strong adhesion and higher cementing value. The results of the study are promising and encourage using the treated dune sand in engineering construction even with a low percentage use of lime (2%) and volcanic ash (1–3%) as stabilizers.

Pines are widely planted for sand dune stabilization and their cultivation results in the changes in physical, chemical, hydro-physical and water repellency properties. Soil properties were evaluated at three Scots pine plantations (PF1, PF2 and PF3) close to Studienka village, Borská nížina lowland (southwestern Slovakia) during hot and dry summer period. The PF1 site is a newly established plantation, the PF2 site is about 30 years old plantation, and the PF3 site is about 100 years old plantation. Here, we estimated the differences in pH, soil organic carbon content, C , particle size distribution, PSD, saturated, s, and unsaturated, (–2 cm), hydraulic conductivity, water, , and ethanol, , sorptivity, water drop penetration time, WDPT, and repellency index, RI. It was found that C varies most significantly with plantation age, and relative differences in PSD and pH were lower than the relative difference in C . The PF3 site differs the most from the other two, especially in C and in the content of sand fraction. It can be attributed to the older age of the plantation, which represents a more advanced stage of succession accompanied by an accumulation of soil organic matter. Relationships between C , (–2 cm), RI, and WDPT and pine forest age were described by appropriate mathematical models. We found a similarity between (–2 cm) and RI relationships vs. pine forest age (exponential models), and between Cox and WDPT relationships vs. pine forest age (first and second-order polynomial models). The latter similarity can be supported by the fact that soil water repellency is induced by the hydrophobic and amphiphilic components of soil organic matter.

Rainstorms frequently cause runoff and then the runoff carries large amounts of sediments (sand, clay, and silt) from upstream and deposit them on different landforms (coast, plain, lowland, piedmont, etc.). Afterwards, monsoons and tropical cyclones often induce severe coastal erosion and dust storms in Taiwan. Ipomoea pes-caprae (a vine), Spinifex littoreus (a grass), and Vitex rotundifolia (a shrub) are indigenous foredune pioneer species. These species have the potential to restore coastal dune vegetation by controlling sand erosion and stabilizing sand dunes. However, their growth characteristics, root biomechanical traits, and anti-wind erosion abilities in sand dune environments have not been documented. In this study, the root growth characteristics of these species were examined by careful hand digging. Uprooting test and root tensile test were carried out to measure their mechanical strength, and wind tunnel (6 m × 1 m × 1.3 m, L × W × H) tests were executed to explore the anti-wind erosion ability using one-year-old seedlings. The results of root growth characteristics demonstrate that I. pes-caprae is superior to S. littoreus and V. rotundifolia. Moreover, uprooting resistance of V. rotundifolia seedlings (0.074 ± 0.032 kN) was significantly higher than that of I. pes-caprae (0.039 ± 0.015 kN) and S. littoreus (0.013 ± 0.005 kN). Root tensile strength of S. littoreus (16.68 ± 8.88 MPa) and V. rotundifolia (16.48 ± 4.37 MPa) were significantly higher than that of I. pes-caprae (6.65 ± 2.39 MPa). In addition, wind tunnel tests reveal that sand wind erosion rates for all three species decrease with increasing vegetation cover, but the anti-wind erosion ability of S. littoreus seedlings is significantly higher than I. pes-caprae and V. rotundifolia. Results of root tensile strength and anti-wind erosion ability clearly show that S. littoreus is superior to I. pes-caprae and V. rotundifolia. Taken together, our results suggest that I. pes-caprae and S. littoreus are beneficial for front line mixed planting, while V. rotundifolia is suitable for second line planting in foredune areas. These findings, along with the knowledge on adaption of foredune plants following sand accretion and erosion, provide us critical information for developing the planting strategy of foredune pioneer plants for the sustainable management of coastal foredune ecosystem.

Artemisia ordosica is an excellent sand-fixing shrub for sand stabilization in northwestern China. Sand dune stabilization, a critically important process, leads changes in abiotic factors, such as soil structure and nutrient contents. However, the effects of factors on an A. ordosica community following sand stabilization remain unclear. In this study, we used canonical correspondence analysis （CCA） to examine the relationships between A. ordosica communities and environmental factors at three habitats： semi-fixed dune （SF）, fixed dune with low-cov- erage biological soil crust （F）, and fixed dune with high- coverage biological soil crust （FC） in Mu Us desert. The mean height and coverage of plants increased with sand stabilization, while species diversity and richness increased initially and then reduced significantly. Correlation analysis and CCA revealed that slope, soil organic carbon, and nutrient contents, proportion of fine soil particles, soil moisture, and thickness of biological soil crust were all highly correlated with vegetation characteristics. These environmental factors could explain 40.42 % of the vege- tation-environment relationships at the three habitats. The distribution of plant species was positively related to soil moisture in the SF dune. Soil moisture, soil nutrient, and fine-particle contents mainly affected plants distribution in the F dune. In the FC dune, distribution of plant species was positively and negatively correlated with the thickness of biological soil crust and soil moisture at a depth 0-20 cm, respectively. The dominance value of typical steppe species increased significantly following sand-dune stabilization and relations between species and samples in CCA ordination bi-plots showed that perennial grasses could invade the A. ordosica community on FC, indicating A. ordosica communities had a tendency to change into typical steppe vegetation with the further fixation. We conclude that the significant differentiation not only occurred in community characteristics, but also in the relationships between vegetation and environmental factors among the three stages of dune fixation. So, restoration of degraded dune ecosystems should be based on habitat conditions and ecological needs.

Rising temperatures and precipitation are important climate change processes around the world. The responses of plants to these trends are still unclear in semi-arid regions, especially in areas with degraded sandy grassland. To provide insights into the response in these regions, we investigated responses of vascular plants to warming and increased precipitation in mobile dunes, fixed dunes and grassland, which represent the series of sand dune stabilization by plants in semi-arid northeastern China. Plant biomass, especially the aboveground biomass, varied significantly ( P  < 0.05) among dune categories. Total plant density in the fixed dunes and grassland was 1.9 and 1.7 times that in the mobile dunes. Species richness differed slightly but significantly ( P  < 0.05) among the habitats. Increasing precipitation in a drought year (65.5% of the long-term average annual precipitation) by 30% did not significantly affect any plant variable. By contrast, warming significantly decreased the belowground biomass, total biomass, species richness and plant total density. In summary, in semi-arid region with sandy soil, additional precipitation slightly improved plant performance, but increased temperature decreased plant performance. Soil texture, which determines the balance between moisture retention and evaporation, may be a key factor in determining these responses when precipitation is unusually low.

Background Poor physical and chemical properties of sand dune soil are the main constrains in afforestation of sand dune in desertified area. The aim of this study is to improve the physical and chemical properties of dune soil in Elrawakeeb Dry Land Station using organic wastes as a fertilizer source and amendments, for sustainable sand dune stabilization program. Salvadora persica L. seedlings were transplanted in a 2 m × 2 m plots and treated with: sawdust (SW), chicken manure (CH), chicken manure with sawdust (CH + SW), sawdust with inorganic fertilizer (SW + IF), sewage sludge (SS), sewage sludge with sawdust (SS + SW), and control (C). The treatments were arranged in a randomized complete block design with four replicates. The soil chemical properties were determined from soil samples collected from the fixed sand dune (0–20 cm depth) in the second year after application. Results Application of organic amendments significantly ( P  = 0.001) increased soil organic carbon by 224 %, available P by 139.9 %, total nitrogen by 142.9 %, and mineral nitrogen by 83.5 % and decreased soil pH by 5.6 %. Conclusions Incorporation of organic waste in desertified sandy dune soils increased its nutrient content and hence sustained biological fixation of sand dunes.

/ This paper examines the use of the European dune pioneer plant Ammophila arenaria (marram or European beach grass) for dune stabilization in South Africa in the past and present, its present distribution in South Africa, and the perceptions of coastal management agencies and the public about its further use. The planting of A. arenaria became the most important means of dune stabilization, by human intervention, along the South African Cape coast in this century. Its modern distribution from the semiarid west coast to the subtropical shores of the Eastern Cape extends through various climatic zones. Although historical data are missing for some areas, there is no indication of its unaided spread. A. arenaria occurs at most sites because of its prior planting. The South African climate appears to affect its vigor. However, concern about the use of the alien grass has been raised since it has proved to be a highly invasive species in other parts of the world, particularly along the North American west coast and in Tasmania. While the CSIR (Council of Scientific and Industrial Research) promotes its use, CNC (Cape Nature Conservation) follows a policy that restricts the use of any alien plant, including A. arenaria, and requests further research on its invasive properties. Although a questionnaire survey shows that stabilization sites featuring large areas of A. arenaria are accepted by the South African public, current coastal management practices need to be analyzed critically. A thorough investigation of the potential invasiveness of A. arenaria on South African coastal dunes will be essential and shed new light on the American A. arenaria problem.KEY WORDS: Ammophila arenaria; Marram; European beach grass; Dune stabilization; South Africa; Coastal managementhttp://link.springer-ny.com/link/service/journals/00267/bibs/24n4p467.html