For centuries, vegetation has been utilized to enhance dune stability and provide coastal protection. Marram grass (Calamagrostis arenaria) is the most commonly transplanted species on engineered coastal dunes in the Netherlands. However, the geomorphic behavior of engineered foredunes relative to neighboring natural foredunes remains unknown. This study utilizes historical airborne laser surveys, multispectral satellite data, and 2023 field surveys to compare the spatial and temporal patterns of sand accretion and vegetation health of the dike-in-dune in Katwijk, NL, with those of the southern neighboring Berkheide from 2015 to 2023. Results show that average annual sand accretion at the Berkheide foredune was about 1.5 times as much as at the dike-in-dune. Average annual increases in vegetation health, as represented by normalized difference vegetation indices, are roughly equal and less than 0.1 at both the dike-in-dune and Berkheide foredunes. This study observed a generally positive correlation between average annual accretion and vegetation health for each foredune. However, in areas of permanent and temporary beach structures, the Berkheide dune appeared to be the most adversely impacted. This information suggests that the foredunes are growing similarly-although the dike-in-dune is engineered-which is promising for urban coastal communities with coastlines visible leeward.
Dunes are widely distributed on Earth and other extraterrestrial bodies, yet relatively little is known about what controls their maximum size. Earth's megadunes (>100 m tall) have traditionally been attributed to constraints including atmospheric boundary layer depth, substrate bedrock type, and sediment supply. However, global mapping results presented here reveal that megadunes preferentially occur near mountains and within dunefield depressions. Megadune height-spacing transition from a power-law relationship to a near-normal distribution, and their aspect ratio (Ra) with height shifts from inverse to direct proportionality. To investigate their underlying formation mechanisms, we focus on how topography influences megadune development under conditions of sufficient sand supply and constant wind regime, using a dune simulation model. Simulation results indicate that both positive (mountain-like) and negative (basin-shaped) topographies generate abrupt shear stress gradients, triggering rapid localized sand accumulation. Compared to gradual evolution on flat terrains, mountain-depression settings accelerate the dune coarsening process and megadune growth through enhanced sand flux convergence and increased collision rates between migrating dunes. Critically, surrounding topography modifies wind regimes, elevating dune aspect ratios (Ra) as shear stress intensifies. Our proposed topography-aerodynamics-sediment redistribution mechanism for megadune formation on Earth and other extraterrestrial bodies demonstrates that terrain-induced wind regime heterogeneity is the fundamental control governing the formation and evolution of massive aeolian landforms.
The southern Atlantic coastal dunes of South America formed ca. 6000-4000 years ago. Within this dynamic landscape, three dioecious species of Poa occur: Poa lanuginosa, a widely distributed species, and two dune endemics, Poa bergii and Poa schizantha, occupying contrasting microhabitats from foredunes to interdunal slacks and inland grasslands. We investigated the evolutionary relationships, population structure, and extent of introgression among these dune-adapted grasses, conducting a population-level phylogenomic analysis using genotyping-by-sequencing. Genome-wide data provided robust phylogenetic resolution, whereas Neighbor-Net analyses revealed reticulate relationships and admixture among taxa. We tested introgression, and significant signals of gene flow were detected across major groups. Bayesian and discriminant analysis of principal components analyses identified distinct genetic lineages within both dune endemics. Poa bergii comprised three geographically structured genetic groups, and P. schizantha showed clear internal differentiation despite its restricted distribution. Instead, P. lanuginosa has a broad distribution across both dune and continental habitats and was inferred to be a paraphyletic lineage that may represent the ancestral lineage of both dune endemic species. These distinct patterns of divergence and population structure indicate species-specific evolutionary responses to a recent and dynamic dune landscape, in which habitat heterogeneity and differential environmental tolerance have driven lineage diversification. Together, our findings highlight the role of coastal dune dynamics in recent adaptation and speciation. Ongoing gene flow alongside clear lineage structure is consistent with recent and still incomplete speciation among these dune species. Poa schizantha emerged as the most differentiated lineage, combining morphological distinctiveness, ecological specialization, and strong genomic structure. Our results emphasize the importance of integrating population genetics into conservation strategies to preserve both endemic taxa and ongoing evolutionary processes in threatened coastal environments.
Sand dune encroachment poses a significant environmental challenge for peri-urban and rural communities in the North African desert, which is home to more than one-third of the region’s population. The continuous movement of sand dunes disrupts residential development, infrastructure, and agricultural systems, threatening food and energy supplies in regions already sensitive to climate variability. The subsequent decline in habitability in such areas often leads to external migration, which triggers heightened socioeconomic and geopolitical instability. As part of the North African Sahara, the West El-Minya Governorate in Egypt is a crucial case study for Saharan areas where growing dune encroachment compromises extensive and critical agricultural developments. We investigate and quantify the primary drivers of sand movement, including wind speed and direction, surface elevation, slope, land use, vegetation cover, and soil cohesion, through the Sand Dune Encroachment Vulnerability Index. Our results reveal that agricultural soils with inadequate irrigation, particularly those adjacent to bare lands, are most susceptible to encroachment. Furthermore, 14% of the total cultivated area is affected by dune encroachment, resulting in estimated annual economic losses of $263 million. Moreover, ~42% of newly established agricultural lands are situated in zones of very high vulnerability, with anticipated productivity reductions of 25% and annual rehabilitation costs approximately $52 million. Transport infrastructures are also impacted, with key highways incurring $6.5 million annually in sand clearance due to recurring dune interference. The proximity of dune-encroached areas to irrigation canals escalates sedimentation rates, deteriorating water quality and incurring additional dredging expenses of $31.3 million per year, with adverse repercussions for agriculture and fisheries. Our study reveals growing dune encroachment, highlighting the urgent need for targeted, nature-based dune stabilization interventions, such as dune leveling and reclamation, in peri-urban Saharan regions. These measures are crucial for preventing further land degradation, reducing population displacement and regional conflict risks, and maintaining the habitability of arid areas.
This study presents a comprehensive examination of coastal dune morphology, migration, and internal structures in Nitzanim, Israel. Our approach integrated Ground Penetrating Radar (GPR) and satellite analysis to understand their evolution and internal architecture. The methodology involved multi-frequency GPR (500 MHz, 250 MHz, and 100 MHz) for subsurface imaging and multi-temporal Landsat, Sentinel-2, and aerial/UAV imagery, with NDVI (Normalized Difference Vegetation Index) analysis for long-term vegetation cover and dune migration monitoring. Results demonstrate a clear trend of decreasing vegetation cover across the study area from 1995 to 2025, which coincides with increased dune mobility and shifts in dune position, with peak migration rates occurring after a localized anthropogenic change: the construction of an artificial lake in 2005. For example, the northern dune's brink line shifted approximately 71 m eastward from its 1995 position, with its southern segment becoming completely exposed by 2015 due to vegetation loss. Concurrently, processed GPR profiles revealed a coherent sequence of quasi-linear internal reflectors within the dune body, with shallow reflections near the crest exhibiting a distinct eastward inclination, suggesting the prevailing direction of past sediment transport. The consistency of these structural elements across different GPR frequencies highlighted the robustness of the multi-frequency GPR methodology employed. Furthermore, the study revealed a relationship between vegetation dynamics and the internal stratification visible in GPR data. While high NDVI values in 1995 correlated with sand accumulation and a visible accumulation line, a reduction in vegetation cover between 2010 and 2025 coincided with an apparent decrease in vertically accreted stratification in GPR profiles, suggesting a relative increase in lateral dune migration during the most recent phase. The combined multidisciplinary approach offers crucial insights into the complex history of dune stabilization, reactivation, and migration in the Nitzanim coastal dunes. It contributes to process understanding in aeolian geomorphology, informing environmental management and conservation strategies in dynamic desert landscapes.
Background: Juniperus macrocarpa Sm. is a key shrub species of the Mediterranean coastal dune systems. The species, considered vulnerable, often shows fragmented or declining populations due to coastal erosion and human pressure. However, along a protected stretch of the northern Tuscany coast it displays an opposite trend, with an apparent expansion of the species. Methods: To assess recent population dynamics, we compared high-resolution aerial imagery from 2013 with UAV orthophotos from 2023 across two dune systems of the Migliarino-San Rossore-Massaciuccoli Regional Park (Italy). The dune profile was divided into three belts (B1: shifting dune; B2: consolidated grassland dune; B3: consolidated juniper dune). A total of 368 plots (10 × 10 m) were analyzed to quantify temporal changes in individual abundance and vegetation cover. Results: Over the ten-year period, total abundance increased from 99 to 342 individuals (+245%) at Lecciona and from 117 to 324 individuals (+177%) at Marina di Vecchiano. Mean cover per plot increased significantly at both sites (overall p < 0.001), with the strongest proportional increases recorded in the seaward belts (B1: up to +1220% in abundance and +4500% in cover) revealing a clear shift from an inner-dune concentration in 2013 to a more homogeneous spatial distribution across the entire dune system in 2023. Conclusions: Under conditions of low anthropogenic disturbance, shoreline stability, or geomorphological progradation, J. macrocarpa is able to expand well beyond its recognized ecological niche. These findings demonstrate the central role of geomorphological and disturbance regimes in driving coastal dune vegetation dynamics and highlight the need for adaptive, site-specific management strategies for the long-term conservation of priority habitat 2250/EUNIS N1B.
Coastal dunes are highly vulnerable ecosystems that require adequate bioindicators for effective biodiversity monitoring. Although moths are recognized as good bioindicators in many contexts, their diversity patterns in these habitats remain understudied. This research examines the taxonomic and functional diversity of noctuoid moths in a well-preserved, protected dune system in Central Italy (Adriatic coast). Specifically, the study aimed at investigating how vegetation composition, and hence dune zonation, influences noctuoid diversity and traits. Moth sampling was carried out on an annual basis using UV LED traps in both shifting and fixed dune zones. Vegetation surveys were conducted in spring using 4 m × 4 m plots. We compared noctuoid species richness, species abundance distribution patterns, and trait attributes between the two dune zones in relation to vegetation characteristics. We also evaluated the congruence in species composition and abundance between dune zones for both moths and plants. Sampled noctuoids included 98 species (78 Noctuidae, 18 Erebidae, 1 Nolidae, and 1 Notodontidae). The presence of habitat-exclusive species underscores the influence of both abiotic and biotic filtering processes in shaping noctuoid assemblages across the seashore-inland zonation. Trait-based analyses and diversity patterns showed clear ecological links between noctuoid assemblages and dune zones. This congruence supports the use of noctuoid moths as effective bioindicators and stresses the need to conserve the entire dune system as an integrated ecological unit.
Sand burial is a dominant physical disturbance in arid dune ecosystems, profoundly altering soil moisture, temperature regimes and mechanical resistance, and thereby constraining belowground plant growth. Rhizomatous clonal plants are particularly dependent on belowground strategies to persist and expand under such conditions, yet how sand burial regulates rhizome expansion and biomass allocation remains poorly understood. We combined two complementary field components in an active dune system in the Ulan Buh Desert, northwestern China. First, rhizome extension of Phragmites australis was monitored descriptively across three burial-depth categories. Second, rhizome traits, ramet recruitment and biomass allocation were examined across three dune microhabitats: interdune lowland, transition zone and windward slope. Rhizomes in deeper burial categories showed greater extension rate and total expansion length than those in shallow burial. Rhizome morphology exhibited strong habitat-dependent variation: internode length and cross-sectional area were greater on windward slopes and transition zones, while rhizomes in interdune lowlands displayed higher length-to-width ratios. Ramet recruitment pathways also shifted spatially, with rhizome-derived ramets dominating in lowlands and tiller-derived ramets prevailing on windward slopes. Biomass allocation further reflected this gradient, with greater vertical investment in lowlands and increasing horizontal allocation toward windward slopes over the growing season. These results show that P. australis exhibits substantial variation in rhizome expansion, clonal traits and biomass allocation across heterogeneous dune environments. Descriptive observations suggest contrasting rhizome expansion under different burial conditions, while habitat-scale patterns reveal variation in clonal organization and biomass allocation. The observed variations in rhizome traits and biomass allocation help explain how clonal plants persist under disturbance in mobile dunes.
Biogeomorphic systems, key providers of ecosystem services, emerge from self-reinforcing feedbacks between landscape-building biota and geomorphic processes. Typically, these feedbacks are considered to operate at an individual patch scale, yet it remains unclear how interactions between patches shape landscapes at larger scales. Here we show how dune-building grasses form functional clusters of interacting patches that strongly amplify engineering capacity. By analyzing a decade of morphological development in an establishing coastal dune system, we discover that dune height is primarily driven by the initial density of neighboring patches, rather than individual patch size. We identify an S-shaped relationship consistent with a spatial percolation threshold: increasing local patch density triggers an abrupt shift from isolated sand-trapping patches to functionally connected clusters that enhance dune growth. This work reveals an important yet overlooked spatial dimension of ecosystem engineering, one that can be harnessed to inform future restoration designs and enhance ecosystem resilience.
The conservation status of the Colombian Caribbean dune system was assessed considering the influence of natural and anthropogenic factors. The study took place in five locations with a gradient of human disturbance. In total, 198 plots and 22 transects were established, three transects in Gairaca and Costa Verde; four in Lipe, and six in Mendihuaca and Salguero. Environmental variables such as dune height, slope, sediment physical-chemical attributes, and anthropogenic impact were assessed in each site, while species composition, frequency, and plant cover were determined for each plot. The results show a correlation between natural and anthropogenic factors and the composition and structure of plant communities growing on the beach and coastal dunes. Human disturbances (urbanized areas, construction, burning, debris, trampling, logging, tourism, groins, sewage, roads, garbage, and sediment extraction) were particularly relevant. Plant cover and species diversity were inversely related to human impact and disturbance. Furthermore, community structure varied among sites: trees and vines were more frequent in the preserved locations, while shrubs and parasitic plants were more abundant in the disturbed sites. Management alternatives should consider the environmental factors (natural and anthropogenic) affecting vegetation to improve the conservation of plant diversity on coastal dunes along the Colombian Caribbean coast.
Task based fMRI data suffers from scanner and physiologic noise. Consequently, finding the task based BOLD responses out of the noise is challenging. To improve the power to detect the BOLD responses, multi-echo (ME) fMRI combined with ICA based denoising (MEICA) and single-echo (SE) fMRI at high temporal resolution (<1 s) have been introduced. Both techniques have been found to give better activation maps than a traditional fMRI experiment at low temporal resolution (1.5-3 s). In this study, we introduced a new U-shaped convolutional neural network DUNE to denoise ME-fMRI data as an alternative to MEICA in 2 ME-fMRI experiments. The resulting activation maps found after denoising with DUNE were compared with those found after denoising with MEICA and similar SE-fMRI experiments at high temporal resolution. Our results revealed that DUNE was successful in reducing the noise while preserving the BOLD effects of interest comparable to MEICA and SE-fMRI. This latter result showed the potential of using a U-shaped convolutional neural network DUNE to denoise ME-fMRI data.
The management of invasive alien species represents a major challenge for the administration of protected natural areas. Understanding the factors that influence the spread of such taxa is essential for designing effective control and eradication strategies. This study investigates the interplay between abiotic, biotic, and anthropogenic factors and the increasing distribution and abundance of Neurada procumbens, an invasive psammophilous plant species, within a protected arid aeolian sedimentary system subject to intensive tourist activity. Based on the comparative results of two chorological inventories conducted 16 years apart, we analysed the colonization dynamics of the taxon and contrasted these with the environmental factors considered to influence the colonization success of N. procumbens. Chorological cartography was applied to 417 UTM grid cells, and abundance increases were categorized to support statistical analysis. Eco-anthropic variables were derived from GIS-based zonal statistics, including aeolian sediment transport, vegetation density, and trail density. Correlation analyses revealed that aeolian sedimentary dynamics are the primary limiting factor for the expansion of the species in the Maspalomas dune field (Canary Islands, Spain). Vegetation density also showed a biotic resistance effect, while trail density indicates a propagule dispersal factor, particularly in newly colonized areas near urban access points. Given its dominance in stabilized dune areas and its expansion over 16 years, the inclusion of N. procumbens in the Spanish Catalogue of Invasive Alien Species is recommended. These insights are currently informing management actions for the monitoring and control of this invasive alien species in the Maspalomas Dunes Special Nature Reserve.
Climate change and anthropogenic activities present significant long-term threats to global biodiversity. To effectively reduce species loss, conservation strategies must rely on detailed insights into suitable habitats for different species and the factors influencing their distribution. This research aimed to provide a checklist of the plant species on the Mediterranean coastal sand dunes in Egypt and investigated the potential impact of anthropogenic and climate change on its distribution in Egypt over the next several decades using remote sensing and species distribution modeling (SDM). The current study revealed that Egypt’s Mediterranean coastal sand dunes host 236 plant taxa, comprising 212 species, 5 varieties, and 19 subspecies, distributed across 75 genera and 39 families. An ensemble modeling approach was employed, incorporating five key. Among these, Random Forest (RF), Boosted Regression Trees (BRT) demonstrated the highest performance. For remote sensing, Landsat imagery (including Thematic Mapper (TM), and Operational Land Imager (OLI) sensors) was utilized. Support Vector Machine (SVM) classification, implemented via Google Earth Engine (GEE), was employed to analyze land use/cover changes. Additionally, future land use projections for 2080 were generated using the CA-Markov simulation model. The study detected major changes in land use along the Mediterranean coast from 1988 to 2024, with projections extending to 2050 and 2070. Based on the ensemble model, the primary environmental drivers of sand dune vegetation were distance from the shoreline, soil organic carbon, precipitation patterns (both total in the wettest month and seasonality), and sand content. The landscape was significantly transformed by the expansion of urban areas, agriculture, and aquaculture. Vegetation diversity is abundant in the Eastern and Western Mediterranean dunes, but scarce in the Deltaic Mediterranean dunes. Future projections using the IPSL-CM6A-LR GCM model for 2050 and 2070, under two climate scenarios (sustainable and low-emissions future: SSP126 and very high greenhouse gas emission: SSP585), suggested a decline in suitable habitat compared to current conditions. These findings emphasize the pressing need for conservation actions, including species reintroduction and strategic planning for both in situ and ex situ conservation in viable habitats.
Coastal sand dunes, shaped by aeolian and marine processes, are critical to natural ecosystems and human societies, making their morphological monitoring essential for effective conservation. However, large-scale, high-precision monitoring of topographic change remains a persistent challenge, a challenge that advanced sensing technologies can address. In this study, we propose an integrated, sensor-based approach using a UAV-mounted light detection and ranging (LiDAR) system, combined with a GNSS-RTK positioning unit and a novel ground control point (GCP) design to acquire high-resolution topographic data. Field surveys were conducted at four time points between October 2022 and February 2023 in the Tottori Sand Dunes, Japan. The digital elevation models (DEMs) derived from LiDAR point clouds achieved centimeter-level accuracy, enabling reliable detection of subtle topographic changes. Analysis of DEM differencing revealed that wind-driven sand deposition and erosion resulted in elevation changes of up to 0.4 m. These results validate the efficacy of the UAV-LiDAR sensor system for high-resolution, multitemporal monitoring of coastal sand dunes, highlighting its potential to advance the development of environmental sensing frameworks and support data-driven conservation strategies.
Fire is often cited as a major disturbance that can induce increased aeolian activity on vegetated sand dunes due to the removal of protective plant cover. This study investigated the spatial and temporal dimensions of burning as an agent of disturbance in partially vegetated linear dunes in the southwest Kalahari. The region is often omitted as a burn-prone area in continental and global burned area studies due to its aridity and proximity to intense temperate zone fires. The MODIS burned area product was used to create an inventory of burned area from 2000 to 2023 to identify trends in burned area extent and occurrence. In addition, MODIS-derived Soil Adjusted Total Vegetation Index (SATVI) was used to calculate vegetation recovery post-burn. 13,310 km2 of the southwest Kalahari dune field burned over the 24-year study period; 11.1 % of the total area. The land management regime significantly impacted on fire frequency (p < 0.001) and size (p < 0.001), with more burns occurring on privately owned land but larger burns within the Kgalagadi National Park. It also significantly affected burn duration (p < 0.001), with the National Park having longer lasting burns. Vegetation recovery is swift after burning, with cover returning to control levels within about two years of being burned. This study highlights how the temporal and spatial disturbance effect of the fire is limited by land management in the study region and rapid vegetation recovery post-burn.
Protected areas are generally designed to conserve biodiversity. However, how much they also contribute to maintaining ecosystem functions that plant diversity supports has rarely been tested explicitly, often because of the lack of historical ecosystem function data. We used a trait-based approach to reconstruct past ecosystem functioning and examine its change over the last 15 years in protected and unprotected coastal dune ecosystems. We resurveyed vegetation in quasipermanent plots and measured several ecosystem functions related to biomass production, carbon, water, nutrient cycling, erosion control, and invasion resistance across six coastal dune sites in central Italy. We used these data to quantify biodiversity-ecosystem function (BEF) relationships. We then used these relationships to hindcast past ecosystem functions based on historical vegetation surveys. Finally, as a case study, we applied this method to assess temporal changes in ecosystem functioning under three protection regimes: national protected areas (i.e., strict protection), Natura 2000 sites (loose protection), and unprotected areas. Biomass production, carbon, and water regulation increased over time in unprotected areas, likely due to an expansion of ruderal and non-native species, which are usually more productive. In Natura 2000 sites, communities showed a decrease in erosion control and invasion resistance associated with the loss of important dune-building species and the spread of non-native species. Only in national protected areas did ecosystem functions not undergo significant temporal changes, and invasion resistance even increased. Our results suggested that ecosystem functioning remained stable over time only in areas under strict protection. More broadly, our results demonstrate the potential for using resurvey data in combination with locally estimated BEF relationships to hindcast past ecosystem functioning. Such an approach can be valuable for monitoring long-term functional changes in response to conservation. Datos de reinspección para pronosticar el cambio en el funcionamiento ecosistémico de las dunas costeras con y sin protección Resumen Las áreas protegidas suelen estar diseñadas para conservar la biodiversidad. Sin embargo, rara vez se ha comprobado explícitamente en qué medida contribuyen también al mantenimiento de las funciones ecosistémicas que sustenta la diversidad vegetal, a menudo debido a la falta de datos históricos sobre estas funciones. Utilizamos un enfoque basado en los rasgos para reconstruir el funcionamiento pasado de los ecosistemas y examinar su evolución durante los últimos 15 años en ecosistemas de dunas costeras son y sin protección. Reinspeccionamos la vegetación en parcelas semipermanentes y medimos varias funciones del ecosistema relacionadas con la producción de biomasa, el carbono, el agua, el ciclo de los nutrientes, el control de la erosión y la resistencia a las invasiones en seis sitios de dunas costeras en el centro de Italia. Utilizamos estos datos para cuantificar las relaciones entre la biodiversidad y las funciones del ecosistema (BEF). Después utilizamos estas relaciones para realizar una predicción retrospectiva de las funciones del ecosistema en el pasado con base en estudios históricos de la vegetación. Por último, como estudio de caso, aplicamos este método para evaluar los cambios temporales en el funcionamiento del ecosistema bajo tres regímenes de protección: áreas protegidas nacionales (es decir, protección estricta), sitios Natura 2000 (protección flexible) y áreas no protegidas. La producción de biomasa, el carbono y la regulación del agua aumentaron con el tiempo en las zonas no protegidas, probablemente debido a la expansión de especies ruderales y no nativas, que suelen ser más productivas. En los espacios Natura 2000, las comunidades mostraron una disminución del control de la erosión y de la resistencia a las invasiones, asociada a la pérdida de importantes especies formadoras de dunas y a la propagación de especies no nativas. Solo en las áreas protegidas nacionales las funciones del ecosistema no sufrieron cambios temporales significativos, e incluso aumentó la resistencia a las invasiones. Nuestros resultados sugirieron que el funcionamiento del ecosistema se mantuvo estable a lo largo del tiempo solo en las áreas bajo protección estricta. En términos más generales, nuestros resultados demuestran el potencial de utilizar datos de reevaluación en combinación con relaciones BEF estimadas localmente para pronosticar el funcionamiento ecosistémico del pasado. Este enfoque puede ser valioso para monitorear los cambios funcionales a largo plazo en respuesta a la conservación. 【摘要】 保护地的设立通常旨在保护生物多样性。然而, 由于缺乏生态系统功能的历史数据, 保护地对维持植物多样性所支撑的生态系统功能的贡献程度仍很少得到明确检验。本研究利用基于性状的方法重建了过去的生态系统功能, 并分析了过去15年间受保护与未受保护海岸沙丘生态系统中的变化。我们在意大利中部六个海岸沙丘位点的准永久样地中重新调查植被, 并测量了与生物量生产、碳循环、水循环、营养循环、侵蚀控制及入侵抵抗力相关的生态系统功能指标。我们利用这些数据量化了生物多样性‐生态系统功能关系, 并基于历史植被调查数据, 回溯了过去的生态系统功能。最后, 我们将该方法应用于评估三类保护制度下(严格保护的国家级保护地、宽松保护的Natura 2000保护位点, 以及未受保护区域)生态系统功能的时序变化, 以作为案例研究。未受保护区域的生物量生产、碳调节和水调节功能随时间增强, 这可能是由于生产力普遍较高的杂草和外来物种的扩张。在Natura 2000保护位点, 由于重要沙丘构造物种的丧失和外来物种的扩散, 群落的侵蚀控制功能和入侵抵抗力均呈下降趋势。只有在国家级保护地内的生态系统功能未随时间发生显著变化, 且其入侵抵抗力甚至有所增强。以上结果表明, 只有在严格保护的区域, 生态系统功能才能保持长期稳定。更广泛地来说, 本研究表明将再调查数据与本地估算的生物多样性‐生态功能关系相结合, 有潜力来回溯过去的生态系统功能。该方法对监测保护措施引起的长期功能变化具有重要价值。【翻译:胡怡思;审校:聂永刚】.
The aims of this study were determining monthly and annual litterfall mass, turnover rates, and the relationship between the litterfall of some tree components (needles, branches, bark, and miscellaneous) and various stand parameters in in afforested coastal sand dunes; nutrient- and water-poor ecosystems, having scarce research. The study was conducted on Stone pine (Pinus pinea L.) and Maritime pine (Pinus pinaster Aiton) afforestation in a coastal sand dune on the Black Sea coast of Istanbul. The total annual litterfall was calculated as 4332 kg/ha/year for P. pinea and 4275 kg/ha/year for P. pinaster. Among the total annual litterfall, the needle litterfall accounted for 81% in P. pinea and 85% in P. pinaster. Both needle and total litterfall peaks occurred in August, mainly during summer, due to drought conditions from April to September. Biomass-based turnover rates were calculated for needles, branches, and bark. The needle turnover rate was 0.5208 in P. pinea and 0.4258 in P. pinaster, with higher rates observed in smaller diameter classes. Relationships between litterfall mass, turnover rates, and various stand parameters were examined as well. The stand parameters (except tree count per hectare) and tree components showed significant positive correlations with litterfall and turnover rates, excluding needles. In conclusion, monthly litterfall measurements are important for determining the effects of drought and other environmental factors, managing thin fuel loads in forests under changing climate conditions, and monitoring forest ecosystem dynamics. Turnover rates varied depending on species and stand characteristics, and further research is needed in this area.
The Gurbantunggut Desert, located in the Junggar Basin of Central Asia, is China's second-largest desert and the only mid-latitude desert dominated by extensive fixed and semi-fixed dunes. Despite its distinctive dendritic, honeycomb, and complex dune morphologies, comprehensive sedimentological datasets spanning multiple dune types and spatial positions remain scarce. Here we present a large-scale, systematic dataset of sediment grain-size distributions collected from 67 sampling zones and 424 sites, totaling 1,859 samples across diverse geomorphological units in the Gurbantunggut Desert. Surface and profile samples were collected following standardized protocols and, after rigorous pretreatment, were analyzed using a Mastersizer 2000 laser-diffraction particle-size analyzer. The dataset captures spatial variations in sediment composition among dune types, slope positions, and profiles, reflecting interactions among wind dynamics, sediment supply, and vegetation cover. This open-access dataset provides essential baseline information for studies of dune morphodynamics, aeolian sediment transport, and ecological responses in arid environments, thereby facilitating future research on source-to-sink dynamics, climate-change impacts, and desertification monitoring.
Arbuscular mycorrhizal fungi (AMF) are beneficial microorganisms establishing symbioses with the roots of most plants, supporting their nutrition and health, mainly in nutrient-poor and harsh environments. AMF spores host diverse bacterial communities whose distribution in the different taxa is poorly understood. To this aim we determined the entire diversity of spore associated bacteria thriving in Ammophila arenaria rhizosphere from Mediterranean maritime sand dunes by Illumina sequencing. The two most abundant AMF species, Racocetra fulgida and Racocetra persica disclosed a highly heterogeneous composition of spore bacterial communities. The endosymbiont Ca. Moeniiplasma glomeromycotorum was abundant in both AMF species and detected in R. fulgida for the first time. Ca. Glomeribacter gigasporarum was present only in R. persica. Distinct highly diversified spore-associated bacterial communities were also identified, with 251 Amplicon Sequence Variants (ASVs) affiliated to 69 and 34 genera in case of R. persica and R. fulgida, respectively. The regular detection of Actinomycetota confirmed a relatively stable relationship with AMF spores. Most of the identified bacteria belonged to culturable genera and species, reported to possess key beneficial activities. Our study showed that different AMF genotypes differentially recruited highly diversified and rich spore associated bacterial communities in a natural sand dune system. The isolation in pure culture of such bacteria could boost in-depth studies aimed at revealing their functional role in the complex interactions between AMF, associated bacteria and host plants and their possible exploitation in harsh agroecosystems.
Understanding the response mechanisms of vegetation characteristics and soil enzyme activities to climatic factors in desertified regions is crucial. However, the relationships between vegetation, soil enzyme activities, and climatic factors in dune ecosystems under different anthropogenic disturbances remain unclear. This study, based on in situ observations conducted from 2020 to 2023 in the Horqin Sand Land, systematically elucidates the response mechanisms of vegetation characteristics and soil enzyme activities to precipitation and temperature across different types of sand dunes under enclosure (control), mowing, burning, and grazing treatments. The results indicate that the effects of mowing and burning on vegetation and soil enzyme activities are strongly water-dependent. In sand dunes located in the moisture-rich dune-meadow ecotone, these treatments exhibited compensatory effects, whereas in moisture-limited semi-mobile dunes, they led to inhibitory effects. Grazing, on the other hand, significantly reduced dune vegetation biomass and soil enzyme activities by 9-45%, but markedly increased plant species richness. Correlation analysis revealed that, following mowing and burning, Poaceae species in ecotone dunes were able to rapidly utilize precipitation, exhibiting high sensitivity to rainfall. In semi-mobile dunes where shrubs and herbaceous plants coexist, species with different life forms enhanced their relationships with precipitation through stratified water use. In contrast, grazing damaged vegetation via herbivory and trampling, overall weakening the response of vegetation to both temperature and precipitation. Structural equation modeling revealed that in ecotone dunes, precipitation significantly promoted sucrose enzyme activity only under burning and grazing treatments. In fixed dunes, however, due to the low palatability of Asteraceae species, livestock trampling facilitated litter decomposition and increased fecal inputs, thereby enhancing nutrient availability, and precipitation significantly promoted vegetation growth. Overall, different disturbances modulated the responses of vegetation and soil enzyme activities to climatic factors by regulating soil hydrothermal conditions and resource use efficiency, highlighting the critical role of water availability in controlling ecological processes in desertified regions. This study provides a theoretical basis and technical support for the conservation and restoration of sandy ecosystems.