Search Results (500)

Elevation is a strong proxy for the thermal environment because it causes a predictable drop in temperature and food availability. This restricts cave-dwelling bats to species with specific metabolic traits, such as torpor or migration to avoid cold stress. In this context, we aimed to reveal how thermal niche differentiation structures 25 cave-dwelling bat assemblages along elevation gradients in two of the largest Bulgarian mountains—Stara Planina and Rhodopi. Multivariate PERMANOVA showed significant differences in bat assemblages among elevation groups (F = 1.616, p = 0.046), with altitude and temperature explaining 32.4% of the variance (p = 0.001). A high degree of species turnover (91.12% dissimilarity), driven by temperature niches, was observed: mesophilic Rhinolophus species dominated warm, low-elevation caves, while cold-adapted Myotis species were more common at high elevations. SIMPER analysis identified R. euryale as an indicator in low-elevation caves (p = 0.012) and the M. myotis/blythii complex at high elevations (p = 0.003). Alpha diversity showed no variation across elevation groups (p = 0.293), indicating that species turnover occurs without overall changes to local diversity. Mid-elevation assemblages lacked specific indicator species and resembled high-elevation communities, forming an ecotone. Thermal niche partitioning, as a physiological filter, shapes cave-dwelling bat assemblages and affects climate change range-shift predictions. Full article

Platonia insignis Mart. (Clusiaceae) is a native fruit tree of great ecological and socioeconomic importance in the Brazilian Amazon and Cerrado. However, habitat loss is threatening its genetic variability. We investigated whether habitat fragmentation across the Amazon, Cerrado, and transition zones shapes the genetic diversity and population structure of five natural populations of P. insignis, using ISSR markers. Leaf samples from 13–15 individuals per population were collected, and DNA was extracted using the CTAB protocol. Twelve ISSR primers amplified 149 loci, used to estimate genetic parameters. AMOVA showed that 73.58% of genetic variation occurred within populations and 26.41% among populations (F_ST = 0.261). Amazonian populations exhibited the highest genetic diversity, while transition zone populations had the lowest values. The Cerrado population was genetically distinct and maintained moderate intrapopulation diversity. Bayesian clustering, PCoA, and UPGMA revealed three genetic groups corresponding to the sampled regions. Transitional populations showed high genetic admixture, indicating their role as potential corridors for gene flow. Our results highlight the need to preserve genetically diverse Amazonian populations, safeguard the Cerrado population as an evolutionarily significant unit, and maintain transitional populations to promote landscape connectivity. The study provides a genetic baseline to support conservation and management of P. insignis germplasm resources. Full article

Mountain ecosystems are susceptible to climate change, and alpine treeline ecotones (ATEs) represent one of the significant responsive indicators of climate-driven environmental change. This study examines long-term spatiotemporal dynamics of the ATE across the Eastern Slopes of the Canadian Rocky Mountains (ESCR) from 1984 to 2023, with the objective of assessing whether regional climate warming has influenced ATE extent and elevation across different aspects and watersheds. Multi-decadal Landsat imagery, ERA5-Land temperature data, and topographic variables were integrated within a Google Earth Engine (GEE) framework to map ATEs using the Alpine Treeline Ecotone Index (ATEI), a probabilistic approach designed to capture transitional vegetation zones. Temporal trends were evaluated using non-parametric statistics, correlation analyses, and watershed- and aspect-based comparisons. Results indicate that the total alpine treeline ecotone (ATE) area in the ESCR was approximately 13.3% larger in 2023 than in 1984. However, the temporal evolution of ATE extent and elevation was non-monotonic, and linear trend analyses did not detect statistically significant increasing or decreasing trends over the full study period. ATE elevation and expansion exhibited pronounced spatial heterogeneity, with greater changes occurring on north- and northwest-facing slopes and within selected watersheds. In contrast, summer (July–September) temperatures increased significantly (+2.84 °C), exceeding global land-only warming rates, and vegetation greenness (NDVI) showed a strong, statistically significant positive relationship with temperature. These findings show that while climate warming has clearly increased vegetation productivity, elevational ATE dynamics remain spatially heterogeneous and temporally non-synchronous with summer temperature trends. Full article

The northern agro-pastoral ecotone of China faces persistent trade-offs among cultivated land (CL) protection, energy development, water constraints, and ecological restoration, posing challenges for sustainable human–land interactions. Focusing on Yulin City from 1980 to 2020, this study develops an integrated diagnostic framework coupling pattern–process–trend–mechanism modules to analyze the spatiotemporal evolution, transition pathways, and driving forces of CL change. Results show that CL dynamics over four decades were shaped by nonlinear interactions among natural conditions, policies, economic development, and technological progress. Spatially, CL changes exhibited a distinct divergence, with ecological-driven contraction in the southern region and sandy land-based compensation in the north. Temporally, the transformation evolved from a gradual, nature-dominated stage to a policy-intensive phase characterized by abrupt shifts, followed by a refined regulation stage with multi-factor synergies. Policy interventions and economic incentives emerged as dominant drivers of CL spatial heterogeneity, with interacting factors exerting bidirectional effects. Building on these findings, a Zoning–Optimization–Synergy (ZOS) framework is proposed to support adaptive land governance, emphasizing differentiated management and cross-sector coordination. This study offers a transferable diagnostic approach for understanding CL dynamics in fragile ecotones and provides insights for managing the water–energy–food nexus under ecological transition and climate change. Full article

Accurate alfalfa biomass prediction is crucial for pasture management and sustainable livestock production. However, traditional methods often perform poorly under complex field conditions. To address the limited prediction accuracy of traditional methods under complex planting environments, this study proposes an alfalfa biomass prediction method combining multispectral and LiDAR data with ensemble learning model. Based on the multispectral images acquired by unmanned aerial vehicle (UAV) and airborne LiDAR data, the spectral features, three-dimensional structural features, and their interaction features are systematically extracted at the quadrat scale, and a high-quality modeling dataset is constructed by feature selection. Secondly, an ensemble model for alfalfa biomass prediction was constructed, which was composed of random forest, extra trees, and histogram gradient boosting. After model training, the coefficient of determination (R²) of the integrated model on the test set reached 0.813, and the root mean square error (RMSE) and mean absolute error (MAE) were 0.178 kg m⁻² and 0.146 kg m⁻², which were significantly better than those of similar single models. Under feature combinations, the fusion model was better than that of spectral indices only (R² = 0.773) and LiDAR traits only (R² = 0.576), and the model achieved the highest accuracy from bud emergence to early flowering (R² = 0.917). The overall prediction error of the model was approximately normal distribution, and the absolute error of more than 65% of the samples was less than 0.2. However, there was still a trend of underestimation in the high biomass interval. This research showed that the multimodal data fusion and ensemble learning method could achieve high-precision prediction of alfalfa biomass, which provided reliable technical support for pasture resources monitoring and precision agriculture management. Full article

Planform evolution and terrestrial habitat health of two representative mid-channel bars (Baishazhou bar and Tianxingzhou bar) in the urban reach of the Middle Yangtze River in Wuhan City have not been understood under the combined influences of natural forcing and human activities. Using dry-season Landsat imagery (1989–2020), hydrological records from the Hankou gauging station (1990–2019), and field surveys, we quantified bar-morphology changes and examined the mechanisms underlying their differentiated scouring. We also developed an indicator system to evaluate terrestrial habitat health on mid-channel bars. Indicator weights were determined using a combined weighting approach integrating the Analytic Hierarchy Process and the entropy weight method. Since the Three Gorges Dam began operation, the runoff in the Wuhan reach has decreased only slightly (6.72%), whereas sediment load decreased sharply (69.88%), causing net scouring of both bars. Baishazhou bar, in a straight anabranching reach, lost 43.83% of its area (1989–2020), with erosion concentrated at the head and main channel margin and caving. Tianxingzhou bar, in a mildly curved reach, had moderate shrinkage (26.33%, 1992–2022) as revetments curbed head/right margin retreat. Both bars were “very healthy” in natural attributes, with the Baishazhou bar showing longer water–land ecotone exposure (217 d) and higher vegetation cover (92%). Socially, Baishazhou bar was “sub-healthy” due to unprotected shrinkage, and Tianxingzhou bar was “unhealthy” due to area loss and low permeability of hard works. Overall, both bars were “healthy”. These findings provide a basis for ecological conservation and habitat restoration of bar wetlands. Full article

Long-term fire histories are well-documented across most North American temperate forest systems, yet the fire regimes of high-alpine treeline environments remain poorly understood. Here, we present a millennial-scale fire history from the Sawtooth Fen Palsa (SFP), a rare permafrost fen palsa located in the high-alpine treeline ecotone of the Beartooth Plateau, Wyoming, a permafrost system now unraveling due to recent decades of rapid warming. Analysis of paleoenvironmental proxies from peat sediments overlying the permafrost reveals a multi-century peak in fire activity at the beginning of the record, ca. 10,000 cal yr BP, coinciding with the afforestation of newly deglaciated, ice-free sites. This initial surge in high-severity fire activity was followed by a decline when solar-orbitally driven increases in growing-season temperatures likely promoted forest opening and more surface fire activity within the SFP watershed. High-severity fire activity increased again during the mid-Holocene (ca. 5800–5000 cal yr BP), when effective moisture increased, favoring subalpine forest expansion and increased connectivity of woody biomass (sagebrush and forest), enhancing the potential for canopy fire spread. Only two small fire episodes were recorded in recent millennia when a rapid change in the sedimentation rate may indicate a partial loss of the sediment record. Rapid warming in recent decades has triggered the formation of dozens of thermal collapse ponds across the fen palsa. The frequency of these features has more than doubled since 2000 CE, underscoring the degradation of underlying permafrost in response to changing climatic conditions. Continued warming is expected to cause the complete loss of the permafrost lens and alter ecosystem dynamics, disturbance regimes, and carbon and nutrient cycling in alpine systems throughout the Rocky Mountains. Full article

Against the backdrop of global climate change, climate warming and increasing nitrogen addition are profoundly altering carbon (C) and nitrogen (N) cycling in terrestrial ecosystems. Short-term observations are critical for capturing the initial response trajectories of soil C-N dynamics to environmental stress, providing timely insights into early-stage adaptation mechanisms that underpin long-term ecosystem stability. This study investigated the interactive effects of these drivers on soil C and N transformation rates, component dynamics, and their coupling relationships in a warm steppe and a warm shrub grassland within the forest–steppe ecotone of northwestern Liaoning Province. We employed field-controlled experiments using open-top chambers for warming in combination with four nitrogen addition gradients. Results showed warming plus high N addition increased soil total N but reduced net N mineralization, supporting the “N saturation hypothesis”. Though N addition generally suppressed the C conversion rate, low-level N (5 g N m⁻² a⁻¹) mitigated C loss and enhanced it under warming. Soil organic C and microbial biomass C drove C transformation. Warm shrub grassland’s stable mineral-associated organic C pool rose 640.5% (stronger resilience), while warm steppe’s C/N turnover depended on seasons (greater vulnerability); C/N transformations were synchronized in the steppe but independent in shrubland. Full article

Frequent agricultural and pastoral activities in northern China’s agro-pastoral ecotone have resulted in severe soil salinization. Although phytoremediation is currently the recommended remediation strategy, plant growth is often hindered by microbial deficiencies, nutrient limitations, and high salt content. Arbuscular mycorrhizal fungi (AMF) are prevalent in saline soils and have been shown to facilitate the growth of various forage grasses. However, highly efficient “AMF strain–leguminous forage grass” remediation systems are currently lacking in this area. This study examined the impact of nine AMF strains sourced from the Bank of Glomeromycota in China (BGC) on the growth and salt tolerance mechanisms of Medicago sativa and Astragalus adsurgens via pot experiment. The results showed that all the strains, except Funneliformis mosseae BGC NM04A (Fm-2), exhibited significant promotion of the growth of both leguminous forage species. Specifically, the growth of M. sativa increased by 157% to 354%, and that of A. adsurgens increased by 15.2% to 252%. The impact of different strains on plant-soluble sugar and protein content was found to vary, with Rhizophagus intraradices BGC BJ09 (Rin) and Rhizophagus irregularis MUCL 43194 (Rir-1) having particularly pronounced effects. Most of the AMF strains enhanced the uptake of phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) in the shoots of both plant species. Additionally, all strains except for Fm-2 exhibited a significant increase in the K⁺/Na⁺ ratio in M. sativa shoots. In contrast, only Claroideoglomus etunicatum BGC GZ03C (Ce-1) and Rir-1 demonstrated a substantial increase in the K⁺/Na⁺ ratio in A. adsurgens. Following a comprehensive assessment, several highly effective combinations were identified: M. sativa in combination with Ce-1, F. mosseae BGC HUN01A (Fm-1), or Rir-1; and A. adsurgens with Rir-1 or Fm-1. These “forage–AMF strain” combinations have been demonstrated to alleviate salt stress by enhancing mycorrhizal effects, regulating ion homeostasis, and optimizing osmotic regulatory substances. Our findings have clarified the intraspecific and interspecific differences in AMF in mitigating salt stress, emphasizing the potential of AMF as a sustainable strategy to improve the stress resistance and productivity of leguminous forages in the saline agro-pastoral ecotone. Full article

This study evaluated the influence of soil health in riparian and ecotone zones on water quality in four high-Andean rivers (Atillo, Ozogoche, Yasepan, and Cebadas) within the Cebadas River sub-basin, Ecuador. Soil and water samples were collected from 20 sites during three field campaigns (2022–2024). Soil properties included organic carbon concentration, soil organic carbon stock (SOC), bulk density, moisture, and potential microbial activity estimated through laboratory CO₂–C efflux. Water quality parameters were integrated into the National Sanitation Foundation Water Quality Index (NSF-WQI), and riparian condition was assessed using the QBR-And index. Multivariate statistical approaches, including Random Forest and Classification and Regression Trees (CART), were used to identify the most influential predictors of ecosystem quality. Results revealed marked spatial contrasts. Riparian SOC stocks ranged from 22.8 to 32.8 Mg C/ha in the more disturbed Cebadas and Yasepan rivers to 91.4–133.6 Mg C/ha in the better-conserved Atillo and Ozogoche systems. Sites with higher SOC and lower bulk density consistently exhibited better water quality, with NSF-WQI values classified as “good”, whereas more degraded sites showed lower riparian quality and “fair” water quality. Riparian forest quality was strongly correlated with water quality (r = 0.81). Random Forest models identified ammoniacal nitrogen, fecal coliforms, and altitude as the most influential predictors of riparian ecosystem condition. These findings demonstrate that soil health and riparian integrity are tightly linked to water quality patterns in high-Andean fluvial systems and support their integration into ecosystem-based watershed management. Full article

As global climate change intensifies and economic transformation progresses, the agro-pastoral ecotone of northern China faces dual challenges of stopping ecological degradation and enhancing farmers’ livelihoods. Yunzhou District in Shanxi Province represents a typical ecologically fragile area, where the daylily industry contributes significantly to improving livelihood resilience. This study categorized farmers into three types based on their dependence on daylily income: major-job farmers (50–90% income from daylily), sole agriculture farmers (≥90%), and side-job farmers (<50%). Using questionnaire survey data and the optimal parameter-based geographical detector method, we evaluated and compared the livelihood resilience levels of these farmer types and identified their key explanatory factors. The results showed that (1) major-job farmers exhibited the highest livelihood resilience index (0.165), followed by sole agriculture farmers (0.152), whereas side-job farmers exhibited the lowest (0.138); (2) significant differences in livelihood resilience existed across farmer types (p < 0.05); and (3) health status was a common key factor across all types, while factors such as traffic accessibility, policy awareness, social security, and information acquisition capability exhibited differential effects among groups. These findings provide empirical evidence to guide targeted livelihood interventions and sustainable transitions in the agro-pastoral ecotone. Full article

Haloxylon ammodendron plantations constitute a dominant vegetation component of the desert–oasis ecotone in the arid and semi-arid regions of northwest China, playing a critical role in maintaining oasis stability and ecological security. However, the effects of converting natural desert ecosystems into plantations on the soil food webs of arthropods remain poorly understood, particularly with respect to how these effects vary across plantation age. To address this knowledge gap, we conducted a field investigation in the desert–oasis ecotone of the middle reaches of the Hexi Corridor, Gansu Province. Using pitfall trapping, we sampled two key arthropod taxa (arachnids and soil mesofauna) from control areas (natural deserts) and H. ammodendron plantations representing different ages (young and old). The results indicated that both young and old plantations were associated with significantly higher abundance and richness of arachnids, soil mesofauna, mites, and springtails compared with natural deserts, with springtail richness exhibiting a further significant increase in old plantations. Arachnid responses to plantation conversion were strongly structured by body size. Medium arachnid abundance increased in both young and old plantations, whereas large arachnid abundance increased only in young plantations and declined in older ones. In contrast, small arachnid abundance exhibited significant increases exclusively in old plantations. In addition, relationships between arachnid, mite and springtail abundance varied with plantation age: the ratio of large arachnids to mites and springtails declined significantly in old plantations relative to young ones, while the corresponding ratio for small arachnids showed an opposite pattern. Variations in soil mesofauna community composition were primarily explained by shrub cover, herbaceous cover, coarse sand proportion, silt-clay content, and soil soluble salt, which together accounted for 48.9% of observed variation. For arachnids, soil mesofauna as a food resource significantly enhanced abundance and richness. Moreover, shrub cover and silt-clay content were also drivers of arachnid community variation, jointly explaining 6.7% of variance. Overall, the establishment of H. ammodendron plantations promoted the diversity of both arachnids and soil mesofauna, but their relationships shifted dynamically with plantation age, leading to a reorganization of detrital food web structure and functioning. Full article

Wetlands play essential roles in sustaining biodiversity, maintaining hydrological stability, and regulating the climate. Subalpine wetlands are particularly rare in Northeast China, yet their floristic composition and diversity patterns remain poorly studied. To fill this knowledge gap and address the lack of baseline plant data for this region, this study conducted systematic field surveys in the subalpine wetlands of Fenghuangshan, Heilongjiang Province, with the aim of assessing plant diversity, dominant floristic types, and community differentiation. The result showed a total of 100 vascular plant species were recorded, belonging to 38 families and 69 genera. Four nationally protected Class II species were also identified, underscoring the region’s conservation importance. Across the three representative plant associations, the Carex limosa-Carex lasiocarpa association exhibited markedly higher species richness, Simpson diversity, and Shannon diversity than both the Salix sericeo-cinerea and Pinus pumila-Rhododendron aureum associations, reflecting pronounced community-level variation in biodiversity. The floristic characteristics at the species level also pointed to a predominantly temperate distribution and showed a pronounced vascular plant flora, which is characterized by the ecotone between temperate and boreal biogeographical zones, directly underpinning the different composition of the communities. This study presents a detailed baseline assessment of plant diversity and floristic composition in the Fenghuangshan subalpine wetland ecosystem. In response to the limited understanding of such ecosystems in East Asia, this research provides crucial foundational data. Furthermore, by contextualizing these results with ecological patterns observed in Northern European wetlands, the study places the local findings into a broader, global perspective. The results offer essential scientific support for biodiversity monitoring, ecological conservation planning, and the future restoration of subalpine wetlands in Northeast China. Full article

Future climate change poses unprecedented challenges to agricultural production worldwide. Therefore, designing region-specific rotation patterns is crucial for achieving synergies among multiple objectives, including agricultural productivity and ecological conservation. Based on a long-term field experiment in the Northern Agro-pastoral Ecotone of China, we calibrated and validated the Agricultural Production Systems Simulator (APSIM) and simulated rotation patterns involving four representative crops under eight climate scenarios, including warming, extreme precipitation, and combined temperature–precipitation changes. Analysis combined with carbon footprint assessment was employed to quantitatively evaluate the productivity, ecological benefits, and economic returns of different rotation patterns. The results showed that warming generally reduced crop productivity and economic returns, weakened soil carbon sequestration, and increased net carbon emissions across rotation patterns. Increasing intensity of extreme precipitation further constrained the capacity of rotation patterns to enhance yields, improve incomes, and reduce carbon emissions. Under scenarios of warming and extreme precipitation, the faba bean–oat rotation pattern was found to be the most effective for increasing crop yields, while the faba bean–potato rotation is beneficial for enhancing the incomes from local agriculture. The potato–faba bean rotation pattern was most effective for environmental sustainability due to low net carbon emissions. The findings provide a scientific basis for developing diversified planting strategies with synergistic multi-objectives in the Northern Agro-pastoral Ecotone of China, contributing to food security and sustainable agricultural development under a changing climate focused on changes in temperature and precipitation. Nevertheless, the potential effects of rising atmospheric CO₂ concentrations may be incorporated in future studies. Full article

African grasses deliberately introduced for cattle forage have become among the most destructive invaders of tropical wetlands globally, yet invasion mechanisms and management strategies remain poorly understood. We conducted field experiments examining competition dynamics between the invasive African grass Echinochloa pyramidalis and native wetland species in La Mancha, Mexico—a Ramsar site of international importance. Experiment 1 tested invasion potential within native Sagittaria lancifolia zones using four treatments: control, herbicide removal, E. pyramidalis transplant, and combined removal + transplant. Repeated-measures ANOVA showed significant treatment and time effects on invasion success, with vegetation removal facilitating invasion (relative importance value increasing from 0 to 149.4 ± 26.6 after 18 months) while transplants alone failed to establish (RIV < 7.0). Sagittaria maintained 35–48% biomass across treatments, demonstrating coexistence capacity. Experiment 2 examined natural invasion of the vegetation ecotone over 49 months. Mixed-effects models revealed that E. pyramidalis increased dominance in its zone (β = 9.98, z = 4.77, p < 0.001) but showed minimal expansion into the adjacent Sagittaria habitat, indicating propagule limitation rather than competitive exclusion as the invasion constraint. Sagittaria removal within E. pyramidalis zones significantly reduced invasion temporal increase (β = −6.44, z = −2.18, p = 0.030), suggesting biotic resistance. Results demonstrate that E. pyramidalis possesses invasion potential but requires disturbance to overcome establishment barriers. These findings support prevention-based management prioritizing disturbance limitation in intact wetlands and demonstrate that hydrological management maintaining permanent flooding (>30 cm depth) can effectively control established invasions by exploiting C4 photosynthetic limitations. Conservation implications for Mexican coastal wetlands—which lack legal protection equivalent to mangroves despite comparable ecosystem services—are discussed. These findings inform evidence-based management of African grass invasions in tropical wetlands worldwide. Full article