Species distribution models are widely used for conservation planning, but their long-term predictive performance is rarely evaluated using independent field data. We evaluated how accurately habitat suitability models predict the distribution of the Mongolian gazelle (Procapra gutturosa) by comparing model outputs with empirical distribution maps collected approximately a decade later. Potential habitats (all environmentally suitable areas) and optimal habitats (core areas with the highest predicted suitability) were modeled using MaxEnt based on occurrence records collected between 1994 and 2015 in southeastern Transbaikalia and eastern Mongolia together with biologically meaningful environmental predictors. The final modeling dataset consisted of both georeferenced field presence records and supplementary spatially generated points representing uniformly occupied areas. Model predictions were subsequently evaluated using independent field observations collected during 2020–2025 following rapid recolonization of the study region.Field mapping showed that gazelles occupied 35,694 km2 in winter and 15,145 km2 in summer. Agreement between predicted and observed distributions was substantially higher for winter habitats than for summer habitats, indicating that snow-related predictors effectively captured the primary ecological constraints on winter distribution. The largest discrepancies between predicted and observed distributions occurred in summer habitats, highlighting ecological factors that are insufficiently represented by commonly used environmental predictors, particularly forage conditions and soil overmoistening associated with summer precipitation.Overall, the study demonstrates the importance of long-term evaluation of species distribution models using independent field data and highlights the need to incorporate climate-sensitive predictors when forecasting range dynamics of steppe ungulates under ongoing climate change. Conversely, accurate mapping of species distributions can help identify and refine critical environmental thresholds that determine species persistence, which is particularly important under ongoing rapid climate change.
Flight initiation distance (FID) and Distance fled (DF) are two common behavioural metrics used to assess how prey perceive threats from predators. Although widely studied in vertebrates, these are poorly measured in invertebrates, and even less in toxic or chemically defended species. We examined FID and DF in the aposematic, sexually dimorphic painted grasshopper, Poekilocerus pictus, in response to an approaching human. Because predation risk can vary between sexes, habitat type, and time of day, we predicted that these factors would influence grasshopper escape behaviours.Females, which are larger and heavier than males, showed shorter FID and DF. Adult females also have shorter forewings than males. These morphological differences help best explain sex-based variation in escape behaviour. Interestingly, we found grasshoppers that did not escape when approached. The probability that a non-escaping individual was female was significantly higher than that of a male. Habitat also influenced escape responses. Grasshoppers in wooded grasslands (dense) were less likely to fly compared to those in open grasslands. Our study shows that even aposematic, chemically defended prey engage in risk-avoidance behaviours to reduce the likelihood of accidental injury or death from larger organisms such as herbivores, and these risks may be sex-biased.
In arid regions, litter decomposition is primarily constrained by precipitation and phosphorus (P) deposition. A 360-day field experiment was carried out to examine the interactive effects of precipitation and P addition on this process. Precipitation and P addition significantly reduced litter C/P and N/P ratios, while enhancing β-1,4-glucosidase (BG), leucine aminopeptidase (LAP), and laccase (LAC) activities. These coordinated changes reduced relative lignin accumulation and collectively accelerated litter decomposition. These results demonstrate a pronounced synergistic effect of precipitation and P addition on litter decomposition. Under ambient precipitation, P addition reduced lignin remaining and increased the litter decomposition rate (k). However, LAC activity declined, probably due to combined microbial metabolic adjustment and photochemical degradation. Under increased precipitation, k did not differ significantly between 2.5 and 5 g P m−2 yr−1, suggesting P saturation under these conditions. Overall, our findings show that water and P inputs interact non-additively to regulate litter decomposition in hyper-arid deserts, with P effects depending on water availability. Accurate predictions of dryland carbon (C) turnover under global change should explicitly account for water–P interactions and their saturation effects.
Seed dormancy limits recruitment in many cactus species by restricting germination even under favorable environmental conditions. In Opuntia streptacantha, dormancy is reinforced by physiological constraints and the lignified endocarp, which imposes a strong mechanical barrier. We evaluated whether seed-associated fungi influence germination across eight Mexican populations. In Experiment 1, germination was higher in non-surface-sterilized seeds than in surface-sterilized seeds, suggesting a facilitative role of naturally occurring seed-associated microorganisms. In Experiment 2, seeds were inoculated with Trichoderma gamsii, Cladosporium cladosporioides, and Fusarium chlamydosporum. Fungal treatments increased germination relative to controls, with F. chlamydosporum showing the strongest positive effect under experimental conditions (up to 78%). Significant provenance × treatment interactions indicated that the magnitude of fungal effects differed among seed sources, highlighting intraspecific variation in seed–microbe interactions. Scanning electron microscopy revealed fungal colonization and localized modifications of the endocarp surface, suggesting a potential interaction between fungal growth and seed coat structure; however, further studies quantifying seed biomechanics, water uptake, and fungal enzymatic activity are needed to confirm the mechanisms involved. These findings highlight the importance of considering seed provenance and microbial interactions when developing microbial-assisted restoration strategies for arid ecosystems.
In arid ecosystems, heterogeneity in ground substrate may influence vegetation dynamics. Along the lower Tarim River, we investigated whether shallow clay layers are associated with contrasting growth of Populus euphratica forests. We integrated microtremor surveys, high-resolution soil profiling at 20-cm intervals, and root investigations across three replicate plots per stand type using a paired-plot design. A consistent shallow clay layer at 180–240 cm depth was identified in declining stands but absent in thriving stands. Within this layer, bulk density reached 1.38 g/cm3, and coarse root weight density was reduced by 88% compared with thriving stands. Soil moisture in the root zone (0–180 cm, above the shallow clay layer) remained below 7%, whereas moisture below the layer (240–300 cm) was 11–12%, values similar to those in thriving stands at equivalent depths. The shallow clay layer also accumulated higher total organic carbon (0.37 g/kg), total nitrogen (225 mg/kg), total phosphorus (535 mg/kg) and total salts than overlying layers. These patterns suggest that the shallow clay layer may restrict root penetration and reduce vertical water connectivity between the root zone and deeper moisture sources. This subsurface perspective suggests that local ground substrate properties may help refine ecological water conveyance planning in arid regions.
Plant–plant recruitment networks provide a useful framework to examine how species interactions shape community structure, yet their drivers remain poorly understood in extremely arid environments. We describe the recruitment network of a Sonoran Desert plant community and evaluate the relative roles of species abundance and phylogenetic distance in determining interaction frequencies and network structure. The network was modular and sparsely connected, comprising ten core species, fourteen satellites, and four strict transients. Most canopy–recruit interactions were positive, suggesting facilitation at the community level. Phylogenetic structure was weak, showing a non-significant tendency towards clustering and no detectable phylogenetic signal in interaction patterns. Species abundance was found to be the best predictor of interaction frequencies, whereas phylogeny-based models failed to provide a good explanation. However, none of the models based on abundance, phylogenetic distance, or their combination were able to reproduce the observed network properties. This mismatch indicates that, although recruitment is largely driven by abundance-dependent encounter processes, the realization of interactions is constrained by additional ecological filters not captured by these predictors. These results highlight the context dependence of recruitment dynamics and the limited role of phylogenetic relatedness in structuring plant interactions under extreme aridity.
Termites are well-known ecosystem engineers, yet the ecological influence of arboreal-nesting species remains poorly understood, especially in semi-arid environments. We investigated whether the subterranean gallery networks of the arboreal termite Constrictotermes cyphergaster create functional soil microsites in the Brazilian Caatinga. We compared soil CO2 efflux beneath termite-influenced soil directly connected to arboreal nests against adjacent reference soil, accounting for seasonal variations. Our results show that termite-influenced soils exhibit CO2 efflux rates up to 4.7-fold higher than surrounding areas, acting as persistent metabolic hotspots. This enhancement persisted across rainfall gradients, despite contrasting responses to precipitation, indicating that termite-influenced soils maintain consistently higher respiration under varying moisture conditions. Notably, the elevated soil CO2 efflux observed in termite-influenced soils was decoupled from surface temperature and did not vary among host tree species, indicating that these differences are primarily driven by termite engineering rather than by root-derived respiration. Termite-influenced soils also displayed higher organic matter and potential acidity. These findings demonstrate that arboreal termites extend their functional influence vertically into the soil, generating significant biogeochemical heterogeneity. By uncovering this “invisible” subterranean footprint, our study highlights the overlooked role of arboreal termites in regulating soil carbon dynamics and ecosystem functioning in semi-arid landscapes.
Climate variability, and change in the long-term, will threaten the stability of vegetation phenology. In this study, long-term changes to the start (SOS), end (EOS) and length of the growing season (LOS) of trees were examined in semi-arid savannah woodlands. A 2000–2025 archive of Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) data from the MODIS (MODerate resolution Imaging Spectrometer) MOD13Q1 product was used. Long-term (1995–2025) rainfall and temperature data from nearby meteorological stations indicated climate trends. Vegetation index (VI) values were plotted against their respective 16-day dates. SOS was detected as the seasonal commencement of EVI increases, EOS as EVI reductions, and LOS as the SOS–EOS time frame. Tree and grass metrics were separated using their respective phenology triggers: annual temperature and rainfall cycles. Warming was detected using long-term trends in mean monthly minimum temperature. The best-fit trend models indicated warming by 0.6–1.2°C. Total annual rainfall was highly variable (coefficient of variation 30–36%). Tree SOS and EOS varied year-to-year, but LOS increased by nearly one month. Remotely sensing savannah tree phenology metrics separately from grass using historical VI images can be more reliable with temperature and rainfall data as interpretation aids.
The Taklimakan Desert is a principal source of atmospheric dust, affecting regional climate, air quality, and cross-border ecosystems. This study quantifies the seasonal, spatial, and interannual variability of three dust categories, namely suspended dust (dust optical depth, DOD > 0.1), blowing dust (DOD > 0.5), and sandstorm (DOD > 1.0), using 23 years (2000–2022) of Moderate Resolution Imaging Spectroradiometer (MODIS) derived monthly dust storm frequency (MODFDS product) at 0.1° resolution. Parametric and non-parametric tests were applied, and the satellite classification was compared against ground-based visibility and present-weather observations from seven stations for 2022. Suspended dust was the most frequent and spatially extensive category, blowing dust was concentrated in the central and south-eastern basin, and sandstorm activity was localised near dune fields and river deltas. Spring was the most active season for all three categories. The categories differed significantly in mean frequency (one-way ANOVA F(2,66) = 978.9, p < 0.001, η2 = 0.97; repeated-measures ANOVA partial η2 = 0.99), and were positively correlated (r = 0.46–0.82). Basin-aggregate Mann–Kendall tests, including the Hamed–Rao variance-corrected test, detected no statistically significant monotonic trend in any category over 2000–2022 (p > 0.4); localised tendencies are apparent in the spatial trend field. Ground comparison yielded moderate, statistically significant correlations (r = 0.38–0.52, p < 0.001), strongest for sandstorm, for which the root-mean-square error was also the smallest (6.2 percentage points, against 22.3 for blowing dust and 33.9 for suspended dust). The multi-threshold framework is reasonably consistent with surface observations and offers a transferable approach for dust monitoring in arid regions with sparse ground networks.
The Caatinga, a semiarid Brazilian biome, is the largest tropical dry savanna forest in South America. With a high environmental heterogeneity, it has a great complexity of communities and endemic species. Among the microorganisms found in the Caatinga, arbuscular mycorrhizal fungi (AMF) form symbiotic associations that increase nutrient absorption and the tolerance of plants to biotic and abiotic stresses. This study aimed to determine the structuring factors of AMF communities across three Caatinga ecoregions (9 areas in total), which differ in soil and vegetation: Northern Sertaneja depression (shrub & tree savanna), savanna-forest Borborema Plateau (most humid and elevated), and dry shrubland Raso da Catarina. These hypotheses were tested: (1) AMF communities differ in composition and structure among the ecoregions; (2) Raso da Catarina has the greatest AMF richness and diversity; (3) edaphic factors (pH and phosphorus content) are key determinants for differences among AMF communities. Multivariate analyses showed that richness, diversity, and composition of AMF communities differed among the ecoregions, represented by 73 species of 19 genera, predominantly Acaulospora, Glomus, and Rhizoglomus. The Northern Sertaneja depression had greater richness, diversity, and abundance of spores than the other areas. Soil moisture, aluminum, calcium, pH, sum of bases, and silt were the structuring elements of these AMF communities. This study highlights the importance to better understand the ecological aspects in the Caatinga ecoregions related to AMF, providing scientific bases for conservation strategies to protect these symbionts, which are fundamental to the resilience of semiarid ecosystems in the face of climate change.
The Safe and Just Space (SJS) framework integrates ecological ceilings and social foundations to define the conditions under which human development can remain both environmentally sustainable and socially equitable. Although interest in SJS has grown rapidly, research remains fragmented across planetary boundaries, the doughnut economy, social–ecological systems governance and sustainability transitions. Consequently, a comprehensive synthesis of the conceptual evolution, research themes and future directions of SJS is still lacking. This study combines bibliometric analysis with a critical literature review to synthesize the conceptual evolution, thematic development, and major advances in SJS research, and to identify priorities for future research. The results show that SJS research began by defining ecological ceilings through the planetary boundaries and safe operating space frameworks, expanded to incorporate social foundations through the doughnut model, and subsequently evolved through concepts such as the safe and just corridor and safe and just Earth system boundaries, which emphasize transition pathways, justice principles, and human well-being. Research has evolved from identifying environmental limits to assessing coupled social–ecological systems, and more recently to translating SJS concepts into policy and place-based sustainability practice. Existing studies mainly focus on boundary quantification and localization of SJS, interaction mechanisms between ecological ceilings and social foundations, and scenario analysis for governance applications. However, several key challenges remain, including the equitable translation of global boundaries across spatial scales, limited understanding of boundary dynamics and long-term scenario simulation, unclear linkages among ecological safety, social justice, and human well-being, and inadequate representation of the dynamics of coupled human–nature system evolution. Future research should focus on developing equitable principles for translating global boundaries to regional and local scales, strengthening the identification of dynamic boundary changes and long-term sustainability pathways, clarifying the relationships between ecological safety, social justice, and human well-being, and advancing analytical frameworks for coupled human–nature systems. Collectively, these efforts will help shift SJS research from boundary identification towards understanding long-term sustainability transitions.
Understanding drought dynamics in arid and semi-arid regions is essential for climate adaptation and sustainable resource management. This study assessed multi-decadal drought variability in Darfur, western Sudan, from 1981 to 2025 using the Standardized Precipitation–Evapotranspiration Index at a 12-month timescale (SPEI-12). Monthly precipitation and temperature records from North, West, and South Darfur were analysed using piecewise linear regression, Bayesian Information Criterion (BIC)-based breakpoint detection, and Breaks for Additive Seasonal and Trend (BFAST) analysis. A precipitation–temperature proxy was used for climatic water balance because potential evapotranspiration data were unavailable. Results revealed statistically significant positive SPEI-12 trends across all regions, indicating a gradual reduction in cumulative drought severity. West Darfur exhibited the strongest trend (0.0463 yr−1; R2 = 0.356), followed by South Darfur (0.0407 yr−1; R2 = 0.277), whereas North Darfur showed a weaker trend (0.0198 yr−1; R2 = 0.065) and greater interannual variability. Although piecewise regression detected no long-term structural breaks, BFAST identified episodic climatic transitions. Severe drought events persisted, particularly during the early 1980s and in recent years. Overall, drought evolution in Darfur is consistent with the broader post-1990s Sahelian hydroclimatic recovery while exhibiting pronounced spatial heterogeneity, providing a basis for drought monitoring and climate adaptation in arid environments.
In recent decades, Spain has experienced an expansion of drylands, with an increase of approximately 4% of its surface area, alongside processes of demographic transformation that altered the spatial distribution of the population. The aim of this study is to quantify the population residing in Spain's drylands and to analyse its evolution between 1960 and 2020, as well as the territorial and environmental implications of these changes. To this end, municipal-scale demographic data are combined with climatic aridity maps based on 30-year averages. Three time points are analysed: 1960, prior to the rural exodus; 1991, following its culmination; and 2020, representing the current scenario, applying the corresponding aridity classification to each period. The results show that the population living in drylands has increased by more than 8% over the study period and currently accounts for nearly 80% of the country's total population. This growth has occurred mainly in semi-arid and arid areas, while non-drylands regions have experienced a sustained demographic decline. This imbalance, combined with the concentration of water-intensive economic activities such as agriculture and tourism in regions characterised by structural water deficits, increases pressure on natural resources and contributes to the intensification of soil degradation and desertification processes.
Reclaimed water is increasingly used to restore arid terminal wetlands, but its ecological effects remain unclear. Using the Dongdao Haizi Wetland as a case, we developed an improved Remote Sensing Ecological Index (MRSEI) that incorporates salinity, based on Landsat imagery on GEE. We analyzed spatiotemporal ecological quality changes from 2000 to 2025 and their drivers using spatial autocorrelation and PLS-SEM. Results show that water area expanded from 3.85 to 38.97 km², and ecological quality improved with a stable spatial pattern. Biological factors were the dominant positive drivers, while human restoration efforts also contributed. This study reveals a hydrological–ecological pathway for wetland recovery in arid regions.
Rural communities in Ethiopia play a significant role in managing agrobiodiversity through their rich indigenous knowledge in conserving diverse plant species. Beekeeping serves as a key practice for supporting local biodiversity. Despite its importance, research on the systematic contribution of beekeeping to agrobiodiversity in Ethiopia remains limited. This study seeks to assess the specific role of beekeeping in promoting biodiversity conservation within crop farming systems in the Eastern Amhara region, Ethiopia. Semi-structured interviews were used to document community backyard management practices and local knowledge. The quadrate method was used to assess vegetation structure and species diversity. Results showed that beekeepers selectively preserve both exotic (e.g., Eucalyptus camaldulensis, Prosopis molle) and indigenous (e.g., Cordia africana, Acacia spp., Ziziphus spina-christi) plant species in their home gardens based on their significance for beekeeping. Beekeeper home gardens showed marginally higher floral species richness (13.80 ± 5.00 vs. 12.55 ± 4.99), Shannon–Wiener diversity (2.08 ± 0.34 vs. 1.92 ± 0.53), and evenness (0.83 ± 0.08 vs. 0.78 ± 0.14) than non-beekeeper gardens (values are means ± SD). In small garden systems, consistent improvements across multiple diversity metrics indicate enhanced floral resource availability. This pattern suggests a balanced community structure and ecological relevance that extends beyond statistical significance. Higher Rényi profiles observed in beekeeper gardens suggest that beekeeping practices, such as the deliberate planting and maintenance of nectar- and pollen-producing plants, are associated with greater plant diversity and may have implications for ecosystem resilience. Integrating beekeeping into community forestry and watershed management could further enhance biodiversity conservation and rural economic development.
Due to global warming, extreme weather increasingly threatens terrestrial carbon sinks. Research on the asymmetric response of aboveground biomass density (AGBD) to precipitation anomalies and its multidimensional drivers remains limited. Using the Asymmetry Index (AS) and multi-source remote sensing data, we systematically revealed the asymmetric response mechanism of forest AGBD in China to dry and wet conditions during 2000−2020. Nationwide, forest AGBD showed a slight negative asymmetry (mean AS = −0.01), with negative AS covering 51.70% of the forest area. Coniferous forests exhibited a weak negative asymmetry (AS = −0.0643), whereas broad-leaved and mixed forests showed positive asymmetry (AS = 0.0406 and 0.2838, respectively). Driving mechanism analysis indicated that monthly maximum temperature (Tmx) was the dominant factor for broad-leaved forests, whereas annual precipitation variability (CVPR) primarily governed coniferous and mixed forests. The asymmetric responses of broad-leaved forests were positively affected by Tmx, CVPR, and mean annual precipitation (MAP), with intensification when high temperature and precipitation variability co-occurred. Coniferous forest responses were jointly regulated by CVPR, Tmx, and MAP, while mixed forests were jointly regulated by CVPR, MaxAGBD, and Tmx. These findings enhance understanding of AGBD responses to precipitation changes and provide a scientific basis for elucidating forest carbon cycling mechanisms.
The continuous release of sand barrier microplastics (PLA-MPs) from polymer sand barriers during weathering in arid sandy areas poses potential ecological risks that are not yet well understood, particularly regarding their effects on vegetation growth and soil ecosystems in desert environments. This study used Agriophyllum squarrosum, a typical sand-fixing pioneer species, and soil from the Ulan Buh Desert as the research system to increase ecological relevance. This study systematically evaluated the concentration-dependent effects of PLA-MPs on the plant–soil system in an arid sand-fixation area using an integrated multi-indicator approach combined with PLS-SEM. Through pot experiments with different concentrations of PLA-MPs, combined with structural equation modeling, the effects on plant growth, physiological traits, soil nutrients, and enzyme activities were evaluated. The results indicate that PLA-MPs significantly inhibited plant biomass and physiological performance, while promoting the accumulation of soil carbon and nitrogen and altering their stoichiometric ratios. However, enhanced soil nutrient levels did not translate into plant growth benefits, reflecting constrained nutrient uptake and utilization. Overall, PLA-MPs exhibited dual effects in arid sandy areas, suppressing plant growth while increasing soil nutrient accumulation, suggesting potential ecological risks associated with polymer sand barriers in desertification control. These findings provide new insights into plant–soil responses to biodegradable microplastics in arid sand-fixation ecosystems and contribute to the ecological risk assessment of polymer-based restoration materials in desert environments.
