Background Ecosystem services(ESs)are fundamental to ensuring human well-being and sustainable development.However,the complex nonlinear relationships between ESs and social systems are still not fully recognized at p...Background Ecosystem services(ESs)are fundamental to ensuring human well-being and sustainable development.However,the complex nonlinear relationships between ESs and social systems are still not fully recognized at present.Here,we used a comprehensive indicator framework,a coupling coordination degree(CCD)model,and a GeoDetector model to measure the CCD and development level of ESs and social systems in Sanmenxia City,Henan Province,China from 2000 to 2020,analyze the spatial patterns and temporal variations of their development,and quantify the influence of 15 factors on the spatial heterogeneity of their CCD.Results We observed that the increase of social system development level in Sanmenxia City was higher than that of ESs'provisioning capacity.From 2000 to 2020,the ecosystem service index value of Sanmenxia City increased by about 25%,while the level of social system development increased by 118.9%.The coordination between ESs and social systems improved by 25%,indicating that their relationships were shifting from trade-offs to synergies.Lushi County(one of the six administrative regions of Sanmenxia City)had the highest level of CCD,but the overall coordination remained relatively weak in Sanmenxia City,and none of the six administrative regions achieved a high level of coordination.CCD was influenced by multiple interacting factors,with topography and land use patterns being the primary drivers.Conclusions Optimizing the spatial layout of ecological space,agricultural space,and urban space based on natural geographic patterns can be an effective way to improve CCD.Accordingly,we identified the impacts of potential barriers on sustainable development and provided multiple possible effective actions.Our findings deepen the knowledge and understanding of the“human-nature relationships”,which are of great significance in promoting the synergistic development of social and ecological systems.展开更多
Background The temperate grasslands are facing numerous pressures from global change.Despite their essential ecological and economic role,how their microbial communities react to multiple varying factors remain obscur...Background The temperate grasslands are facing numerous pressures from global change.Despite their essential ecological and economic role,how their microbial communities react to multiple varying factors remain obscure.In this study,we simulated three global change drivers,i.e.,nitrogen deposition(ambient N vs.elevated N,a N vs.e N),precipitation increase(ambient precipitation vs.elevated precipitation,a P vs.e P),and mowing,represented experimentally by clipping(unclipped vs.clipped,u C vs.CL),together in all possible combinations in a temperate semi-arid grassland ecosystem.Results Nitrogen addition had negative effects on the richness of bacterial and fungal communties,significantly changed their structures(P<0.05)and increased their dissimilarities(P<0.05),while water addition had positive effects on fungal and protist communities and significantly stimulated theα-diversity of protist communities under N addition without clipping,which was in contrast to the effect in clipped plots.Clipping had a marginal effect on fungal communities and significantly affected protist communities(P<0.05).A notable interactive effect of N and precipitation on the structure of bacterial communities and a significant interactive effect of clipping and precipitation on protists were found.Combination effects of N with precipitation or clipping on module aggregation of metanetworks were also observed between u C and CL,as well as a P and e P meta-networks.Bacterial,fungal,and protist communities varied in their assembly mechanisms,and their assembly processes differed in response to the three global change factors.Conclusions Overall,N,water addition,and clipping individually and/or interactively,in distinct degrees,altered soil microbial interaction,community structure,and the potential function in a semi-arid steppe.These findings enhance our understanding of soil microbial community assembly and provide a scientific basis for managing temperate grasslands,particularly in the context of global change's impact on ecosystem function and stability.展开更多
Background Increasing atmospheric nitrogen(N)deposition is a major threat to plant diversity globally.Recent observations show that the reduced-to-oxidized(NH_(x)/NO_(y))ratio of N deposition has been changing spatial...Background Increasing atmospheric nitrogen(N)deposition is a major threat to plant diversity globally.Recent observations show that the reduced-to-oxidized(NH_(x)/NO_(y))ratio of N deposition has been changing spatially and temporally.How and to what extent different N forms(i.e.,NH_(x)and NO_(y))influence grassland plant species loss are still unclear.Methods We employed a field manipulative experiment by using three N forms[i.e.,Ca(NO_(3))_(2),NH_(4)NO_(3),and(NH_(4))_(2)SO_(4)]with six N addition levels(0,4,8,16,24,32 g N m^(-2)year^(-1))in a temperate grassland and conducted a greenhouse experiment culturing four plant species corresponding different plant functional groups under Ca(NO_(3))_(2)or(NH_(4))_(2)SO_(4)addition.Results Results from our field experiment showed that the plant species loss rate was greater under NH_(4)^(+)-N than NO_(3)^(-)-N enrichment.Plant species loss was driven by light asymmetry under NO_(3)^(-)-N enrichment,while it was co-driven by light asymmetry and soil acidification under NH_(4)NO_(3)enrichment.Under NH_(4)^(+)-N enrichment,light asymmetry,pH decrease,NH_(4)^(+) toxicity,and metal toxicity jointly affected species loss.The greenhouse experiment provided direct evidence that legumes and forbs are more physiologically susceptible to NH_(4)^(+)-induced toxicity than grasses.Conclusions Our results emphasize that N forms play a vital role in affecting grassland plant diversity.This suggests that regions with higher NH_(x) enrichment may experience more severe plant diversity losses as N deposition continues to increase.Therefore,appropriate measures should be adopted to mitigate species losses.展开更多
Background The forest floor humus layer is an important carbon pool and serves as a key interface that influences forest soil carbon and nutrient cycling,especially in temperate and boreal forests.Over the past decade...Background The forest floor humus layer is an important carbon pool and serves as a key interface that influences forest soil carbon and nutrient cycling,especially in temperate and boreal forests.Over the past decades,China has implemented numerous forestry ecological programs,leading to an increasing quantity of forest floor litter and the formation of humus layers,which has altered the interface between aboveground litter and surface soil.Our previous study revealed that these alterations affect the litter decomposition rate;however,it is still unclear how the litter decomposition process changes,how nutrients are released or imported and the extent to which these changes depend on the humus layer.Results In this study,we used a 535-day in situ litterbag experiment to monitor the litter decomposition process and nutrient variations under forest floor humus layer removal in a Pinus sylvestris var.mongolica plantation in Northeast China.The results revealed that the litter decomposed quickly when a forest floor humus layer was present,with the decomposition rate constant(k value)increasing from 0.122 to 0.328.Accordingly,during decomposition,the litter C,N and P concentrations increased,whereas their contents varied only slightly(with the exception of the litter P content,which decreased significantly)compared with those in the treatment where the humus layer was removed.However,both the litter C and N contents decreased,whereas the litter P content increased significantly compared with the initial litter content.Moreover,the litter C:N,C:P and N:P ratios decreased significantly during decomposition.In addition,the microbial community diversity of the litter showed no significant change,whereas the relative abundances of several major fungal and bacterial taxa at the phylum and genus levels varied significantly.Furthermore,redundancy analysis revealed effective relationships among the k values,chemical traits and microbial communities,and the least squares method suggested that the C,P and C:P ratios of the litter were significantly correlated with the litter decomposition rate.Conclusions These results enhance our understanding of the role of the humus layer in forest soil-plant carbon and nutrient cycling and should be considered in carbon cycle models in the future.展开更多
Background The mangrove ecosystem has the highest carbon sink potential which significantly contributes to bringing carbon neutrality.Understanding the carbon stock dynamics along the age of forest stands in the mangr...Background The mangrove ecosystem has the highest carbon sink potential which significantly contributes to bringing carbon neutrality.Understanding the carbon stock dynamics along the age of forest stands in the mangrove forest ecosystem is of significance for managing the forests and their carbon accumulation.This study aimed to estimate the forest structural attributes,biomass and total ecosystem carbon stock(TECS)of old natural(age>50 years)and young planted(age~20 years)mangrove forest stands at Bichitrapur Mangrove Reserve Forest in eastern coast of India.We also attempted to understand the interrelationship of structural attributes,biomass and soil properties in the mangrove forests.To achieve the results,twenty random plots were established(size:20 m×25 m)and suitable allometric equations along with species-specific wood density values were used to estimate the biomass and carbon stock.Results Altogether,29 plant species(18 exclusive and 11 associate species)were recorded.The mean total biomass(±SE)and soil organic carbon(at 30 cm depth)were 165.31±20.89 t ha^(-1)and 40.20±1.24 t C ha^(-1)for young stands,and 586.12±56.74 t ha^(-1)and 49.68±2.39 t C ha^(-1)for old stands,respectively.Among mangrove species,Avicennia marina contributed the highest vegetation biomass in both forest stands(59.72 t ha^(-1)and 262.28 t ha^(-1)in young and old stands,respectively),followed by Avicennia officinalis(35.05 t ha^(-1))and Sonneratia apetala(26.09 t ha^(-1))in young stand and Avicennia alba(169.28 t ha^(-1))and Avicennia officinalis(115.58 t ha^(-1))in old stand.The mean TECS was 235.62±27.34 t C ha^(-1).The contribution of vegetation and soil to TECS was 63%and 37%in the young stand,whereas in the old stand it was 83%and 17%,respectively.The correlation analyses revealed that mean stand height(r=0.87),basal area(r=0.99),soil nitrogen(r=0.76),potassium(r=0.78),and carbon(r=0.80)were significantly positively correlated with total biomass at p<0.01.Conclusions Our results demonstrate that old mangrove forest stands store substantially high carbon stock than young planted forest stands,implying the role of forest age in determining the carbon storage potential of mangrove ecosystems.展开更多
Background The effects of war on biodiversity,habitats,ecosystem services,and water,seafood,and fishing resources are complex and long-lasting,yet their ongoing environmental analyses are limited.The Russia–Ukraine W...Background The effects of war on biodiversity,habitats,ecosystem services,and water,seafood,and fishing resources are complex and long-lasting,yet their ongoing environmental analyses are limited.The Russia–Ukraine War(2022–present)comprises a unique ecological situation to examine biodiversity effects on the distinctive cold-temperate northern Black Sea ecosystem,which has an intriguing biogeographic history and high endemism resulting from geographic isolation and differentiation.Results We summarize negative and positive effects from the War on the aquatic(marine,estuarine,and freshwater)biota and their habitats,focusing on investigations by the Institute of Marine Biology,National Academy of Sciences of Ukraine.Negative effects include toxins and habitat damage from oil spills,shelling,mining,explosions,flooding,and fires;along with disregard of Protected Areas.Positive effects are reduced anthropogenic loads from less shipping,fishing,trawling,recreation,hydraulic engineering,construction,and tourism.The Kakhovka Dam's destruction on June 6,2023 was the greatest ecological catastrophe to date,causing extensive downstream flooding with freshwaters and pollutants that destroyed many populations and habitats.We discern that many effects have been temporary,with habitats and species replenishing,and some reverting to their historical biota characteristic of lower salinity regimes.However,significant habitat destruction,disturbances,and pollutant damages remain.Since many of the native species evolved in conditions favoring broad salinity,temperature,and oxygen tolerances,the northern Black Sea ecosystem appears pre-adapted for ecological recovery and persistence,which may equate to ecological resilience during and after the War.Conclusions The native biota exhibits long-term adaptiveness to marked salinity and temperature fluctuations,alongside a background of invasive species.An evolutionary and recent history of broad environmental tolerances by a large proportion of Black Sea species may enhance their ability to withstand marked environmental changes,including habitat destruction,as during the Kakhovka Dam's breakage and other stressors that continue during the Russia–Ukraine War.The Black Sea community's overall ecological resilience is likely to facilitate persistence and adaptation to the War's effects and the accelerating impacts of climate change,increased global transportation,and invasive species—meriting worldwide conservation agency focus and cooperation.展开更多
Background Accurate measurements of aboveground biomass(AGB)are essential for understanding the planet's carbon balance.The Atlantic Forest of the Serra do Mar in southeastern Brazil contains large areas of well-p...Background Accurate measurements of aboveground biomass(AGB)are essential for understanding the planet's carbon balance.The Atlantic Forest of the Serra do Mar in southeastern Brazil contains large areas of well-preserved remnants,characterized by mountainous terrain with significant orographic contrasts along its elevation gradient.This diverse landscape creates a variety of biophysical factors that strongly influence the spatial distribution of AGB.This study aims to estimate AGB using a hybrid geostatistical methodology,regression kriging simulation(RKS),to analyze AGB spatial distribution at a local scale(84 plots,each 0.01 ha)across a small forest fragment covering the entire tree-covered area(8777 ha).Building on traditional regression kriging method,this study introduces an innovative approach by incorporating Gaussian simulation to interpolate residuals,allowing RKS to account for uncertainties in the estimation process and create new results.This allows us to clearly distinguish exogenous ecological processes from endogenous ones before reaching the model's final estimate.Results Four regression kriging models were created,and the best-performing model used the Enhanced Vegetation Index and direct solar radiation(DSR),achieving an R^(2) of 55%.A Gaussian simulation was performed to interpolate the residuals of this model.The final results indicate that RKS provides accurate AGB estimates(RMSE=1.333 Mg/0.01 ha and R^(2) of 77%).Additionally,the inclusion of DSR as a new predictor variable enhances the precision of AGB estimates.The analysis showed that 63%of the sample pairs exhibited measurable spatial dependence.Conclusions Regression kriging simulation is proposed using Gaussian simulation,altering the classical application of regression kriging.For this,a case study was conducted in the Atlantic Forest of Serra do Mar to estimate the spatial distribution of tree biomass in a forest fragment of this region.We demonstrate that the proposed method better captures the heterogeneity of the region and produces more comprehensive results than regression kriging.Regression kriging simulation estimates tree biomass by considering the actual fluctuations of the spatial distribution of tree biomass in the region,taking into account exogenous and endogenous ecological processes,addressing random noise,and allowing the creation of dynamic maps for use by environmental managers.展开更多
Background Insectivorous birds provide a key ecosystem service as predators of folivorous insects. Changes in forest structural complexity and composition, currently underway in temperate forests, may affect the preda...Background Insectivorous birds provide a key ecosystem service as predators of folivorous insects. Changes in forest structural complexity and composition, currently underway in temperate forests, may affect the predation pressure exerted by birds on folivores, by altering the abundance of avian predators. However, studies examining this are few, as well as on how predation rates vary within forest stands. We aimed to address these gaps, by focusing on beech(Fagus sylvatica) trees in managed montane forests of the Black Forest region, in Central Europe. We measured abundance and diversity of birds using point counts on 135 1-ha plots in 2017–2022. To assess bird predation pressure on caterpillars, we placed 3153 artificial caterpillars on selected 24 plots for a week, in the spring of 2021, and inspected them for bird bite marks. We placed caterpillars on up to four focal tree locations in each plot, in both the canopy and the understorey of each tree. We also measured forest structure and composition both at the scale of plots and the vicinity of focal trees.Results We found that higher shrub-layer cover and share of broadleaf trees at the plot scale were associated with higher overall abundance of foliage-gleaning insectivorous birds. However, predation rates on artificial prey appeared to be more closely related with the abundance of single species(particularly the Eurasian chaffinch, Fringilla coelebs), which in turn responded to other facets of forest structural complexity. Within plots, predation pressure was overall higher in the canopy than in the understorey, but this may reflect observer effects rather than true differences between vegetation layers. Predation rates also showed strong variation across trees, being higher in beech crowns with a monospecific neighbourhood, and in saplings surrounded by a mixed-species shrub layer.Conclusions Our results suggest that specific bird species and particular facets of forest structural complexity contribute disproportionately to the predation pressure exerted by birds on caterpillars, and that fine-scale management decisions may also affect the role of birds as predators. However, further research is needed to confirm these patterns and overcome the limitations we identified.展开更多
Background Biological invasions pose severe threats to global biodiversity and human well-being.Invading populations often experience negative growth rates during the‘lag phase',leading to Allee effects,a density...Background Biological invasions pose severe threats to global biodiversity and human well-being.Invading populations often experience negative growth rates during the‘lag phase',leading to Allee effects,a density-dependent phenomenon.Allee effects reduce species fitness or plant performance due to low-density populations.The rapid spread and range expansion of an invader,Hyptis suaveolens(L.)Poit.has been reported to have negative impacts on local biodiversity in the invaded regions of the Vindhyan highlands,India.The present study examines the effects of varied population densities of H.suaveolens on its vegetative trait performance,reproductive output,and density-dependent plant population regulations.Understanding the relationship between the population density and trait modulation ability of H.suaveolens at fine and coarse scales could help strategize for management.Methods The study was conducted in invaded habitats of H.suaveolens in the Vindhyan highlands,India.Population density was divided into low-,medium-,and high-density groups.Plant performance was assessed at two scales—fine scale and coarse scale.Plant performance traits,vegetative growth,and reproductive output were estimated as plant traits(Pl Ts)at the fine scale and patch traits(Pa Ts)at the coarse scale.The plasticity response index(PI)was also estimated among three population densities.Results Results showed that Pl Ts-vegetative and reproductive traits,such as plant height,biomass,and number of seeds,were significantly different across densities,with medium-density individuals showing maximum plant height and plant biomass and high-density individuals exhibiting a higher number of seeds per plant.Pa Ts analysis revealed that plant biomass per patch was similar for medium-and high-density populations,whereas the number of seeds per patch was similar in low-and medium-density populations.PI values revealed that Pl Ts showed low,medium,and high plastic responses,while Pa Ts exhibited low and high plastic responses.Conclusions The study concludes that H.suaveolens exhibits density-dependent plant population regulations.As population density increases,low-density populations grow more rapidly,resulting in denser populations.These populations can negatively impact recipient habitats and,if left unchecked,grow into high-density populations with higher seed production.The study suggests that low-density areas should be considered a high priority for developing efficient and cost-effective management strategies.The present study emphasizes the importance of incorporating Allee effects dynamics in invasion studies for predicting high-risk/priority areas for strategizing invasive species management.展开更多
Background Fluvial fish habitat in the Northeastern and Midwestern U.S. is substantially affected by natural landscape factors and anthropogenic stressors, with climate change expected to alter natural influences and ...Background Fluvial fish habitat in the Northeastern and Midwestern U.S. is substantially affected by natural landscape factors and anthropogenic stressors, with climate change expected to alter natural influences and exacerbate stressor effects. To conserve fluvial fish species in the future, it is crucial to understand which fish habitats will be most strongly influenced by changing climate, which species are most sensitive to climate change, and how changes in individual species will affect entire assemblages. To answer these questions, we modeled fluvial fish distributions under projected changes in climate to understand how climate could affect suitability of fish habitat for 55 widely distributed fluvial fishes with differing thermal preferences in the region. Using boosted regression tree models, we predicted distributions of fishes at a stream reach scale using four contemporary climate variables including annual mean air temperature, annual precipitation, and variation in monthly air temperature and precipitation along with seven natural landscape and anthropogenic stressor variables. We then used projected values from eight general circulation models(GCMs) during 2041–2080 to evaluate potential patterns in species richness, turnover, and range shifts under climate change across the study region.Results Most cold-water and cool-water species were projected to lose habitat;however, projected habitat loss also occurred for certain small-bodied warm-water species. The percentage change in species richness of all 55 species across reaches ranged from-40.4 to 33.93%, with regions of major species richness losses occurring across southern portions of the Northeastern coast and southern Midwest regions. Species turnover ranged from 0 to 43.5% with substantial turnover occurring along the Northeastern coast and upper Midwest.Conclusions Temperature and precipitation variation will influence fish species distribution substantially. Our findings provide multiple measures describing patterns of fish community change under climate change to aid management and conservation of stream fishes in the future.展开更多
Background Describing where distribution hotspots and coldspots are located is crucial for any science-based species management and governance.Thus,here we created the world's first Super Species Distribution Mode...Background Describing where distribution hotspots and coldspots are located is crucial for any science-based species management and governance.Thus,here we created the world's first Super Species Distribution Models(SDMs)including all described primate species and the best-available predictor set.These Super SDMs are conducted using an ensemble of modern Machine Learning algorithms,including Maxent,Tree Net,Random Forest,CART,CART Boosting and Bagging,and MARS with the utilization of cloud supercomputers(as an add-on option for more powerful models).For the global cold/hotspot models,we obtained global distribution data from www.GBIF.org(approx.420,000 raw occurrence records)and utilized the world's largest Open Access environmental predictor set of 201 layers.For this analysis,all occurrences have been merged into one multi-species(400+species)pixel-based analysis.Results We present the first quantified pixel-based global primate hotspot prediction for Central and Northern South America,West Africa,East Africa,Southeast Asia,Central Asia,and Southern Africa.The global primate coldspots are Antarctica,the Arctic,most temperate regions,and Oceania past the Wallace line.We additionally described all these modeled hotspots/coldspots and discussed reasons for a quantified understanding of where the world's non-human primates occur(or not).Conclusions This shows us where the focus for most future research and conservation management efforts should be,using state-of-the-art digital data indication tools with reasoning.Those areas should be considered of the highest conservation management priority,ideally following‘no killing zones'and sustainable land stewardship approaches if primates are to have a chance of survival.展开更多
Background The decomposition of organic matter is among the most important ecosystem processes in forest ecosystems,regulating the carbon and nutrient cycle.However,our understanding about how direct(environment and d...Background The decomposition of organic matter is among the most important ecosystem processes in forest ecosystems,regulating the carbon and nutrient cycle.However,our understanding about how direct(environment and decomposer diversity)and indirect effects(environment via decomposer diversity)contribute to deadwood decomposition is limited.We set up a large real-world deadwood experiment in a mixed mountain forest in southeastern Germany considering beech(Fagus sylvatica)and fir(Abies alba)as substrates.We simultaneously tested effects of canopy cover,amount and heterogeneity of surrounding deadwood and a broad set of fungal diversity measures mediated by environment on deadwood density loss after 10 years.Results Deadwood density loss was mainly explained by tree species and canopy cover.Beech showed higher density loss than fir and density loss was larger in open compared to closed canopies.Even though fungal diversity is mediated by environment,the direct effects on density loss were weak and inconsistent across tree species and fungal diversity measures.Conclusions We found weak support for the fungal diversity–ecosystem process relationship for deadwood decomposition.We suggest that deadwood decomposition and the resulting carbon and nutrient cycles in forest ecosystems are primarily regulated by the tree species selected through forest management and canopy disturbances,particularly in the context of climate change.展开更多
Background The global freshwater biodiversity crisis has led to widespread implementation of measures to counteract environmental degradation and biodiversity loss.While these efforts aim to foster recovery,intensifyi...Background The global freshwater biodiversity crisis has led to widespread implementation of measures to counteract environmental degradation and biodiversity loss.While these efforts aim to foster recovery,intensifying stressors continue to drive complex biotic responses,the trajectories and drivers of which are insufficiently understood.This study examines the roles of abiotic stressors,biotic interactions(e.g.,competition),and land use in shaping ecological status changes across Germany,using data from 1599 river sites sampled at least twice between 2004 and 2022.Results Changes in abiotic stressors emerged as the most consistent drivers of ecological status,explaining substantial variation(R^(2)=0.39)and similar slopes for recovery(β=-0.11)and degradation(β=-0.10).Biotic interactions,particularly interspecific competition,also influenced the ecological status(R^(2)=0.11),with stronger positive effects observed during recovery(β=2.99)compared to degradation(β=1.59).Land use effects varied by context:Streams in catchments with higher cropland or urban areas showed greater likelihood of recovery,whereas streams in forested catchments were more prone to degradation.These results highlight the interplay of abiotic and biotic factors in driving ecological processes of recovery and degradation.Conclusion These findings emphasize the critical role of improving water quality for enhancing biodiversity and ecological status in rivers,while also demonstrating the importance of biotic interactions and land use context in driving recovery dynamics.Integrating these insights into management and restoration efforts can enhance freshwater ecosystem resilience in the face of escalating environmental pressures.展开更多
Background Subtropical forests play a critical role in global carbon cycling but are highly sensitive to climate-d riven precipitation and temperature variability.At China's Dinghushan Biosphere Reserve,observed w...Background Subtropical forests play a critical role in global carbon cycling but are highly sensitive to climate-d riven precipitation and temperature variability.At China's Dinghushan Biosphere Reserve,observed warming(+1.5℃since 2002)and precipitation declines(8.2±1.3 mm/yr)exceed global subtropical averages,yet their combined effects on water-use efficiency(WUE)and carbon exchange remain poorly quantified.Methods Using 21 years of eddy covariance and meteorological data(2002-2022),we analyzed WUE(defined as NEE/ET;g C kg^(-1)H_(2)O)responses to drought events classified via the standardized precipitation index(SPI).Results The reserve experienced increasing drought frequency,with 7 extreme droughts(SPI≤-2.0)post-2010versus 2 pre-2010.Soil moisture extremes(<0.15 m^(3)m^(-3))reduced WUE by 2.35 g C kg^(-1)H_(2)O.Carbon fluxes showed diffe rential sensitivity:ecosystem respiration(RE)declined most sharply(-71.9×10^(-5)g C m^(-2)s^(-1))during extreme droughts,while gross primary productivity(GPP)exhibited non-linear reductions below a 1,200 mm yr^(-1)precipitation threshold.Late-successional forests maintained 0.94 g C kg^(-1)H_(2)O higher WUE than mid-successional stands during droughts,linked to deeper rooting systems(120±15 cm).The identified 3-year recovery lag suggests targeted reforestation during wet intervals(SPI≥1.5)could enhance resilience.Conclusion By establishing quantitative drought thresholds and revealing hydraulic versus non-hydraulic limitations,our findings provide actionable strategies for subtropical forest conservation under climate change.展开更多
Background Recent increases in tree mortality are often attributed to climate, but climate extremes may just be the last of many stressors that have unfolded over many years resulting in tree death. Potentially it is ...Background Recent increases in tree mortality are often attributed to climate, but climate extremes may just be the last of many stressors that have unfolded over many years resulting in tree death. Potentially it is only those trees weakened by mechanical damage or attacks by insects or fungi that are susceptible to climate-mediated mortality, whereas vigorous trees resist periods of unfavorable climate. Although previous studies have explored immediate and catastrophic effects of mechanical damage via blowdowns and stem breakage, few have investigated the delayed effects of mechanical damage on mortality. Taxus is a shade-tolerant genus of subcanopy trees or shrubs distributed throughout the northern hemisphere. Populations of Taxus are in decline worldwide but owing to the tenacity of Taxus in the face of stressors, this decline is poorly understood. Here, we provide spatial evidence that cumulative stress interactions, particularly mechanical damage, contribute to Taxus mortality.Methods We examined 14 years of annual demographic data from the 27.2 ha Wind River Forest Dynamics Plot(WFDP), where woody stems, snags, and deadwood have been tagged, mapped and identified to species. We analyzed the multiple factors associated with tree death, including mechanical damage, pathogens, suppression, beetles, animal damage, and their combinations. We performed spatial pattern analyses with the pair correlation function to investigate the prevalence of density-dependent mortality, effects of neighboring large-diameter trees, and effects of nearby snag fall and deadwood.Results In 2011, there were 29,827 trees within the WFDP of which 2119 were Taxus. Between 2011 and 2024, Taxus declined to 1523 trees(mean annual mortality of 2.79% yr^(-1)). Taxus mortality was not influenced by intraspecific density dependence or the presence of snags but was mainly driven by mechanical damage, pathogens, and suppression. Dead Taxus were strongly associated with deadwood within 2 m of the bole. Structural equation modeling showed that mechanical damage likely increased the vulnerability of Taxus to pathogen infection and exposure to drier gap areas.Conclusions These results suggest that Taxus mortality is rarely due to a single event, but a cumulative process of interacting stressors initiated by falling wood and often culminating in death by other stressors—potentially many years later. The association of newly dead trees with deadwood suggests that falling snags likely contributed to past crown damage, initiating or accelerating a decline spiral. The results emphasize that previous mechanical damage—evidenced by mapped and persistent deadwood—can disproportionately affect tree species, influencing successional dynamics.展开更多
Background Forest ecosystems are in the spotlight for their potential to mitigate anthropogenic carbon dioxide(CO_(2)) emissions through net photosynthesis. However, this mitigation potential can be counteracted by re...Background Forest ecosystems are in the spotlight for their potential to mitigate anthropogenic carbon dioxide(CO_(2)) emissions through net photosynthesis. However, this mitigation potential can be counteracted by respiratory losses, e.g., from soils and the forest floor. With global warming, soil respiration(SR) rates are expected to increase, unless acclimation occurs. Using manual and automated chambers as well as a below-canopy eddy-covariance system, we quantified SR and forest floor net CO_(2) exchange(NEEff) for 13 years throughout an 18-year study period(2006–2010, 2015–2016, 2018–2023) in a mixed deciduous forest ecosystem in Switzerland. We identified the contribution of environmental drivers for SR and NEEff using Extreme Gradient Boosting models and Shapley additive explanations(SHAP) analyses and assessed the long-term temperature sensitivity of SR and NEEff.Results Over the 18-year study period, soil temperature increased significantly and was the main driver of both SR and NEEff, explaining over 50% of their temporal variability. Differences in drivers and magnitudes of SR vs. NEEff were only found in early spring, when the forest floor vegetation showed net CO_(2) uptake. Finally, we found no evidence that SR or NEEff(at mean annual temperatures) had increased between 2006 and 2023. Similarly, no significant change in the temperature sensitivity of SR and NEEff was observed.Conclusions Combining multiple techniques to assess long-term responses of CO_(2) fluxes to environmental conditions with machine learning approaches enhanced our understanding of forest responses to climate change. Moreover, our findings suggest that soil and forest floor respiration already acclimated to warmer conditions, highly relevant for predicting future mitigation potentials of forest ecosystems.展开更多
Background Identifying the processes that govern community assembly along elevational gradients has been a central theme in ecology,especially in montane ecosystems where abundant species and strong turnover are prese...Background Identifying the processes that govern community assembly along elevational gradients has been a central theme in ecology,especially in montane ecosystems where abundant species and strong turnover are present.However,our understanding of how the relative importance of deterministic and stochastic processes varies along elevational gradients remains limited.Here,we compiled a rigorously curated dataset of elevational distributions of 734 breeding bird species across the Hengduan Mountains in China to assess the dominant underlying mechanisms of bird community assembly at both intra-community and inter-community scales across four elevation zones:low,middle,subalpine,and alpine.Results At the intra-community scale,homogeneous dispersal played a pivotal role in driving community assembly of breeding birds across the Hengduan Mountains.Deterministic processes became more influential with increasing elevation,whereas stochastic processes prevailed in low,middle,and subalpine zones.At inter-community scale,assemblages from different elevation zones were more differentiated by dispersal limitation.Non-Passeriformes experienced more obvious influence of homogeneous dispersal but were less subject to dispersal limitation compared to Passeriformes.Conclusions Our findings highlight the role of stochastic processes in shaping biotic communities in montane ecosystems,but this effect is scale-dependent.The transition from stochastic to deterministic processes along elevational gradients suggests that environmental factors become more influential at higher elevations.Species dispersal ability may affect the relative importance of these two processes shaping community assembly.展开更多
Background Tick borne diseases are re-emerging around the world,including India.Information about the occurrence of the tick vectors in different geographical locations is essential for controlling the diseases.Tick s...Background Tick borne diseases are re-emerging around the world,including India.Information about the occurrence of the tick vectors in different geographical locations is essential for controlling the diseases.Tick surveys have not been conducted in many parts of India and information on the current prevalence of tick vectors is not available in all states of India.Many studies have been carried out utilizing modelling methods to predict the distribution of tick species in other countries.The MaxEnt model is widely used for predicting tick species distribution using bioclimatic variables.Lyme disease vectors such as Ixodes sp.,Amblyomma sp.,and Dermacentor sp.are the most commonly predicted tick species.However,very few studies have been carried out to predict the distribution of tick species in India.Haemaphysalis spinigera,the primary Kyasanur Forest Disease vector,was predicted along the Western Ghats using the MaxEnt model.Rhipicephalus(Boophilus)microplus was predicted across India using the generalized linear model(GLM).Identifying the tick vectors in transmitting the infection through conventional survey and identification methods is cumbersome due to the less number of experienced persons available.Prediction of tick vectors of public health concern,including other tick species in different geographical regions of Tamil Nadu,India,is essential for the prevention and control of tick-borne disease in humans and domestic animals.The present study adopts the package‘SSDM’(stacked species distribution models)with R software containing ensemble species distribution models to predict the distribution of tick species using different available environmental and climatic data.Results The categorical variables such as land use and land cover(LULC),soil type,elevation,Bio1,Bio10,Bio15,Bio19 and Bio8 contributed more to modelling the distribution of tick species.MaxEnt,GLM,GBM and GAM are suitable models for predicting the tick species distribution in the present study.Among these models,MaxEnt is the most suitable model for predicting tick species distribution in Tamil Nadu,India.Conclusions Our results suggest that MaxEnt is a suitable model for predicting the distribution of tick species.Both environmental factors such as LULC,elevation and soil type and bioclimatic factors such as temperature and precipitation contribute significantly to predicting tick species distribution in domestic animals in Tamil Nadu.The SSDM package is very useful and user-friendly graphical user interface for modelling the distribution of tick species.However,the package can be further improved by using higher resolution raster variables in larger areas,which is not currently supported.The predicted elevation range of Ha.spinigera distribution could not be provided due to software limitations.展开更多
Background Deforestation for terraced orchards,a common agricultural development pattern in mountainous ecosystems,drastically modifies soil physicochemical and biological properties.This conversion can affect soil mi...Background Deforestation for terraced orchards,a common agricultural development pattern in mountainous ecosystems,drastically modifies soil physicochemical and biological properties.This conversion can affect soil microbial carbon use efficiency(CUE),which is a crucial indicator of soil carbon dynamics.However,the impact of this conversion on CUE remains unclear.Understanding how deforestation affects CUE will help predict soil carbon dynamics and guide the development of sustainable ecosystem strategies in fragile mountainous areas.Methods Herein,the response of CUE to environmental variations induced by deforestation for terraced orchards in an arid valley was explored.We quantified CUE using the^(18)O-labeled water addition method.To identify the underlying driving factors,soil properties and microbial parameters were measured concurrently.Results Microbial CUE declined significantly after forest conversion to terraced orchards.Multiple factors,including soil micro-environmental conditions,stoichiometric traits,enzymatic properties,and microbial community attributes,were all closely associated with CUE.Furthermore,hierarchical partitioning analysis revealed soil stoichiometric traits as the primary drivers of CUE reduction,especially traits associated with the C:N and C:P ratios.During the conversion process,mechanical compaction and horizon inversion increased soil bulk density and clay content,thereby reducing soil aeration.These micro-environmental constraints were closely linked to intensified imbalances in the C:N and C:P ratios between microbes and soil.Along with the reduced soil C:N ratio,these stoichiometric shifts made it more difficult for microorganisms to obtain resources.Therefore,microbial C limitation intensified,soil microbes shifted from being primarily limited by P in forests to being co-limited by C and P in terraced orchards,which in turn stimulated greater microbial investment in resource-acquiring hydrolytic enzymes.Consequently,CUE declined because microbial growth decreased more significantly than microbial respiration.Conclusion In summary,deforestation for terraced orchards in the arid valley reduced CUE by constraining soil micro-environments and resource conditions.These findings advance our understanding of CUE variations following deforestation and have important implications for soil carbon cycling in vulnerable mountain ecosystems.展开更多
Background The impact of vessel-induced waves on macrophyte communities in lakes remains controversial,due to a lack of comprehensive assessments which also consider mechanistic effects on ecological processes during ...Background The impact of vessel-induced waves on macrophyte communities in lakes remains controversial,due to a lack of comprehensive assessments which also consider mechanistic effects on ecological processes during early life stages.This study investigates both the direct and indirect effects of such waves on the early life stages of macrophytes in a case study of Lake W?rthersee,Austria.The study focuses on Characeae species and Najas intermedia which have both experienced significant declines in Lake W?rthersee.Results The linear wave theory was applied to model typical small vessel-induced waves,characterized by wave heights of 0.05–0.30 m and periods of 1 and 3 s.Relevant characteristics for testing remobilization of oospores and seeds like geometric dimensions and density were experimentally determined by field data.Sediment samples from ten locations across six beach sites at depths ranging from 0.8 to 2.2 m were collected and analyzed for oospore presence and sediment texture.Results indicate that maximum wave scenarios can affect oospores and seeds directly by motion activation at water depths down to 3.75 m.Moderate wave scenarios,which are assumed to occur more frequently,can mobilize those particles between 0.75 and 2.25 m water depth.This corresponds to our field data,where 95%of oospores were found in samples from water depths≥2 m.The mobilization disrupts germination processes and impedes the recovery of macrophyte populations.Additionally,in the study lake and other fine-sediment dominated lakes,a significant fraction of sediments can be initiated to motion by small vessel-induced waves,which may indirectly affect germination by altering habitat conditions like turbidity and nutrients.However,grain size distribution showed minimal variation with depth at the same sampling sites,indicating limited sediment redistribution at the selected sampling sites by small vessel-induced waves.No significant correlation was found between oospore abundance and sediment grain size.Conclusions These findings suggest that the impacts of increased traffic of small vessels in lakes may be a key factor contributing to the decline of macrophyte species in shallow waters by motion triggering of oospores and seeds,with broader implications for the recreational management.展开更多
基金funded by the National Natural Science Foundation of China (Nos. 42361144882 to T.L., and 42471322 to Y.H.)
文摘Background Ecosystem services(ESs)are fundamental to ensuring human well-being and sustainable development.However,the complex nonlinear relationships between ESs and social systems are still not fully recognized at present.Here,we used a comprehensive indicator framework,a coupling coordination degree(CCD)model,and a GeoDetector model to measure the CCD and development level of ESs and social systems in Sanmenxia City,Henan Province,China from 2000 to 2020,analyze the spatial patterns and temporal variations of their development,and quantify the influence of 15 factors on the spatial heterogeneity of their CCD.Results We observed that the increase of social system development level in Sanmenxia City was higher than that of ESs'provisioning capacity.From 2000 to 2020,the ecosystem service index value of Sanmenxia City increased by about 25%,while the level of social system development increased by 118.9%.The coordination between ESs and social systems improved by 25%,indicating that their relationships were shifting from trade-offs to synergies.Lushi County(one of the six administrative regions of Sanmenxia City)had the highest level of CCD,but the overall coordination remained relatively weak in Sanmenxia City,and none of the six administrative regions achieved a high level of coordination.CCD was influenced by multiple interacting factors,with topography and land use patterns being the primary drivers.Conclusions Optimizing the spatial layout of ecological space,agricultural space,and urban space based on natural geographic patterns can be an effective way to improve CCD.Accordingly,we identified the impacts of potential barriers on sustainable development and provided multiple possible effective actions.Our findings deepen the knowledge and understanding of the“human-nature relationships”,which are of great significance in promoting the synergistic development of social and ecological systems.
基金financially supported by grants from the National Natural Science Foundation of China (41930643 and 42273084)Natural Science Foundation of Henan Province (242300421039)Science and Technology Development Plan Project of Henan Province (242102110186)
文摘Background The temperate grasslands are facing numerous pressures from global change.Despite their essential ecological and economic role,how their microbial communities react to multiple varying factors remain obscure.In this study,we simulated three global change drivers,i.e.,nitrogen deposition(ambient N vs.elevated N,a N vs.e N),precipitation increase(ambient precipitation vs.elevated precipitation,a P vs.e P),and mowing,represented experimentally by clipping(unclipped vs.clipped,u C vs.CL),together in all possible combinations in a temperate semi-arid grassland ecosystem.Results Nitrogen addition had negative effects on the richness of bacterial and fungal communties,significantly changed their structures(P<0.05)and increased their dissimilarities(P<0.05),while water addition had positive effects on fungal and protist communities and significantly stimulated theα-diversity of protist communities under N addition without clipping,which was in contrast to the effect in clipped plots.Clipping had a marginal effect on fungal communities and significantly affected protist communities(P<0.05).A notable interactive effect of N and precipitation on the structure of bacterial communities and a significant interactive effect of clipping and precipitation on protists were found.Combination effects of N with precipitation or clipping on module aggregation of metanetworks were also observed between u C and CL,as well as a P and e P meta-networks.Bacterial,fungal,and protist communities varied in their assembly mechanisms,and their assembly processes differed in response to the three global change factors.Conclusions Overall,N,water addition,and clipping individually and/or interactively,in distinct degrees,altered soil microbial interaction,community structure,and the potential function in a semi-arid steppe.These findings enhance our understanding of soil microbial community assembly and provide a scientific basis for managing temperate grasslands,particularly in the context of global change's impact on ecosystem function and stability.
基金financially supported by the National Natural Science Foundation of China(42203077,32192462)the Chinese Universities Scientific Fund(2020RC009)the 2115 Talent Development Program of China Agricultural University(1201-00109017)
文摘Background Increasing atmospheric nitrogen(N)deposition is a major threat to plant diversity globally.Recent observations show that the reduced-to-oxidized(NH_(x)/NO_(y))ratio of N deposition has been changing spatially and temporally.How and to what extent different N forms(i.e.,NH_(x)and NO_(y))influence grassland plant species loss are still unclear.Methods We employed a field manipulative experiment by using three N forms[i.e.,Ca(NO_(3))_(2),NH_(4)NO_(3),and(NH_(4))_(2)SO_(4)]with six N addition levels(0,4,8,16,24,32 g N m^(-2)year^(-1))in a temperate grassland and conducted a greenhouse experiment culturing four plant species corresponding different plant functional groups under Ca(NO_(3))_(2)or(NH_(4))_(2)SO_(4)addition.Results Results from our field experiment showed that the plant species loss rate was greater under NH_(4)^(+)-N than NO_(3)^(-)-N enrichment.Plant species loss was driven by light asymmetry under NO_(3)^(-)-N enrichment,while it was co-driven by light asymmetry and soil acidification under NH_(4)NO_(3)enrichment.Under NH_(4)^(+)-N enrichment,light asymmetry,pH decrease,NH_(4)^(+) toxicity,and metal toxicity jointly affected species loss.The greenhouse experiment provided direct evidence that legumes and forbs are more physiologically susceptible to NH_(4)^(+)-induced toxicity than grasses.Conclusions Our results emphasize that N forms play a vital role in affecting grassland plant diversity.This suggests that regions with higher NH_(x) enrichment may experience more severe plant diversity losses as N deposition continues to increase.Therefore,appropriate measures should be adopted to mitigate species losses.
基金supported by the National Key Research and Development Program of China(2024YFD150140302)the Natural Science Foundation of China(Nos.32271843,41888101 and 41871027)the project of forestry science and technology innovation platform(No.LLC20245)
文摘Background The forest floor humus layer is an important carbon pool and serves as a key interface that influences forest soil carbon and nutrient cycling,especially in temperate and boreal forests.Over the past decades,China has implemented numerous forestry ecological programs,leading to an increasing quantity of forest floor litter and the formation of humus layers,which has altered the interface between aboveground litter and surface soil.Our previous study revealed that these alterations affect the litter decomposition rate;however,it is still unclear how the litter decomposition process changes,how nutrients are released or imported and the extent to which these changes depend on the humus layer.Results In this study,we used a 535-day in situ litterbag experiment to monitor the litter decomposition process and nutrient variations under forest floor humus layer removal in a Pinus sylvestris var.mongolica plantation in Northeast China.The results revealed that the litter decomposed quickly when a forest floor humus layer was present,with the decomposition rate constant(k value)increasing from 0.122 to 0.328.Accordingly,during decomposition,the litter C,N and P concentrations increased,whereas their contents varied only slightly(with the exception of the litter P content,which decreased significantly)compared with those in the treatment where the humus layer was removed.However,both the litter C and N contents decreased,whereas the litter P content increased significantly compared with the initial litter content.Moreover,the litter C:N,C:P and N:P ratios decreased significantly during decomposition.In addition,the microbial community diversity of the litter showed no significant change,whereas the relative abundances of several major fungal and bacterial taxa at the phylum and genus levels varied significantly.Furthermore,redundancy analysis revealed effective relationships among the k values,chemical traits and microbial communities,and the least squares method suggested that the C,P and C:P ratios of the litter were significantly correlated with the litter decomposition rate.Conclusions These results enhance our understanding of the role of the humus layer in forest soil-plant carbon and nutrient cycling and should be considered in carbon cycle models in the future.
文摘Background The mangrove ecosystem has the highest carbon sink potential which significantly contributes to bringing carbon neutrality.Understanding the carbon stock dynamics along the age of forest stands in the mangrove forest ecosystem is of significance for managing the forests and their carbon accumulation.This study aimed to estimate the forest structural attributes,biomass and total ecosystem carbon stock(TECS)of old natural(age>50 years)and young planted(age~20 years)mangrove forest stands at Bichitrapur Mangrove Reserve Forest in eastern coast of India.We also attempted to understand the interrelationship of structural attributes,biomass and soil properties in the mangrove forests.To achieve the results,twenty random plots were established(size:20 m×25 m)and suitable allometric equations along with species-specific wood density values were used to estimate the biomass and carbon stock.Results Altogether,29 plant species(18 exclusive and 11 associate species)were recorded.The mean total biomass(±SE)and soil organic carbon(at 30 cm depth)were 165.31±20.89 t ha^(-1)and 40.20±1.24 t C ha^(-1)for young stands,and 586.12±56.74 t ha^(-1)and 49.68±2.39 t C ha^(-1)for old stands,respectively.Among mangrove species,Avicennia marina contributed the highest vegetation biomass in both forest stands(59.72 t ha^(-1)and 262.28 t ha^(-1)in young and old stands,respectively),followed by Avicennia officinalis(35.05 t ha^(-1))and Sonneratia apetala(26.09 t ha^(-1))in young stand and Avicennia alba(169.28 t ha^(-1))and Avicennia officinalis(115.58 t ha^(-1))in old stand.The mean TECS was 235.62±27.34 t C ha^(-1).The contribution of vegetation and soil to TECS was 63%and 37%in the young stand,whereas in the old stand it was 83%and 17%,respectively.The correlation analyses revealed that mean stand height(r=0.87),basal area(r=0.99),soil nitrogen(r=0.76),potassium(r=0.78),and carbon(r=0.80)were significantly positively correlated with total biomass at p<0.01.Conclusions Our results demonstrate that old mangrove forest stands store substantially high carbon stock than young planted forest stands,implying the role of forest age in determining the carbon storage potential of mangrove ecosystems.
文摘Background The effects of war on biodiversity,habitats,ecosystem services,and water,seafood,and fishing resources are complex and long-lasting,yet their ongoing environmental analyses are limited.The Russia–Ukraine War(2022–present)comprises a unique ecological situation to examine biodiversity effects on the distinctive cold-temperate northern Black Sea ecosystem,which has an intriguing biogeographic history and high endemism resulting from geographic isolation and differentiation.Results We summarize negative and positive effects from the War on the aquatic(marine,estuarine,and freshwater)biota and their habitats,focusing on investigations by the Institute of Marine Biology,National Academy of Sciences of Ukraine.Negative effects include toxins and habitat damage from oil spills,shelling,mining,explosions,flooding,and fires;along with disregard of Protected Areas.Positive effects are reduced anthropogenic loads from less shipping,fishing,trawling,recreation,hydraulic engineering,construction,and tourism.The Kakhovka Dam's destruction on June 6,2023 was the greatest ecological catastrophe to date,causing extensive downstream flooding with freshwaters and pollutants that destroyed many populations and habitats.We discern that many effects have been temporary,with habitats and species replenishing,and some reverting to their historical biota characteristic of lower salinity regimes.However,significant habitat destruction,disturbances,and pollutant damages remain.Since many of the native species evolved in conditions favoring broad salinity,temperature,and oxygen tolerances,the northern Black Sea ecosystem appears pre-adapted for ecological recovery and persistence,which may equate to ecological resilience during and after the War.Conclusions The native biota exhibits long-term adaptiveness to marked salinity and temperature fluctuations,alongside a background of invasive species.An evolutionary and recent history of broad environmental tolerances by a large proportion of Black Sea species may enhance their ability to withstand marked environmental changes,including habitat destruction,as during the Kakhovka Dam's breakage and other stressors that continue during the Russia–Ukraine War.The Black Sea community's overall ecological resilience is likely to facilitate persistence and adaptation to the War's effects and the accelerating impacts of climate change,increased global transportation,and invasive species—meriting worldwide conservation agency focus and cooperation.
文摘Background Accurate measurements of aboveground biomass(AGB)are essential for understanding the planet's carbon balance.The Atlantic Forest of the Serra do Mar in southeastern Brazil contains large areas of well-preserved remnants,characterized by mountainous terrain with significant orographic contrasts along its elevation gradient.This diverse landscape creates a variety of biophysical factors that strongly influence the spatial distribution of AGB.This study aims to estimate AGB using a hybrid geostatistical methodology,regression kriging simulation(RKS),to analyze AGB spatial distribution at a local scale(84 plots,each 0.01 ha)across a small forest fragment covering the entire tree-covered area(8777 ha).Building on traditional regression kriging method,this study introduces an innovative approach by incorporating Gaussian simulation to interpolate residuals,allowing RKS to account for uncertainties in the estimation process and create new results.This allows us to clearly distinguish exogenous ecological processes from endogenous ones before reaching the model's final estimate.Results Four regression kriging models were created,and the best-performing model used the Enhanced Vegetation Index and direct solar radiation(DSR),achieving an R^(2) of 55%.A Gaussian simulation was performed to interpolate the residuals of this model.The final results indicate that RKS provides accurate AGB estimates(RMSE=1.333 Mg/0.01 ha and R^(2) of 77%).Additionally,the inclusion of DSR as a new predictor variable enhances the precision of AGB estimates.The analysis showed that 63%of the sample pairs exhibited measurable spatial dependence.Conclusions Regression kriging simulation is proposed using Gaussian simulation,altering the classical application of regression kriging.For this,a case study was conducted in the Atlantic Forest of Serra do Mar to estimate the spatial distribution of tree biomass in a forest fragment of this region.We demonstrate that the proposed method better captures the heterogeneity of the region and produces more comprehensive results than regression kriging.Regression kriging simulation estimates tree biomass by considering the actual fluctuations of the spatial distribution of tree biomass in the region,taking into account exogenous and endogenous ecological processes,addressing random noise,and allowing the creation of dynamic maps for use by environmental managers.
基金Open Access funding enabled and organized by Projekt DEALthe German Science Foundation(Deutsche Forschungsgemeinschaft,DFG),for their doctoral projects in the framework of the Research Training Group Con Fo Bi(grant number GRK 2123/1 TPX)State Graduate Funding of Baden-Württemberg,through the International Graduate Academy(IGA)of the University of Freiburg
文摘Background Insectivorous birds provide a key ecosystem service as predators of folivorous insects. Changes in forest structural complexity and composition, currently underway in temperate forests, may affect the predation pressure exerted by birds on folivores, by altering the abundance of avian predators. However, studies examining this are few, as well as on how predation rates vary within forest stands. We aimed to address these gaps, by focusing on beech(Fagus sylvatica) trees in managed montane forests of the Black Forest region, in Central Europe. We measured abundance and diversity of birds using point counts on 135 1-ha plots in 2017–2022. To assess bird predation pressure on caterpillars, we placed 3153 artificial caterpillars on selected 24 plots for a week, in the spring of 2021, and inspected them for bird bite marks. We placed caterpillars on up to four focal tree locations in each plot, in both the canopy and the understorey of each tree. We also measured forest structure and composition both at the scale of plots and the vicinity of focal trees.Results We found that higher shrub-layer cover and share of broadleaf trees at the plot scale were associated with higher overall abundance of foliage-gleaning insectivorous birds. However, predation rates on artificial prey appeared to be more closely related with the abundance of single species(particularly the Eurasian chaffinch, Fringilla coelebs), which in turn responded to other facets of forest structural complexity. Within plots, predation pressure was overall higher in the canopy than in the understorey, but this may reflect observer effects rather than true differences between vegetation layers. Predation rates also showed strong variation across trees, being higher in beech crowns with a monospecific neighbourhood, and in saplings surrounded by a mixed-species shrub layer.Conclusions Our results suggest that specific bird species and particular facets of forest structural complexity contribute disproportionately to the predation pressure exerted by birds on caterpillars, and that fine-scale management decisions may also affect the role of birds as predators. However, further research is needed to confirm these patterns and overcome the limitations we identified.
基金the Institution of Eminence(IOE),University of Delhithe Science and Engineering Research Board,Department of Science and Technology,India
文摘Background Biological invasions pose severe threats to global biodiversity and human well-being.Invading populations often experience negative growth rates during the‘lag phase',leading to Allee effects,a density-dependent phenomenon.Allee effects reduce species fitness or plant performance due to low-density populations.The rapid spread and range expansion of an invader,Hyptis suaveolens(L.)Poit.has been reported to have negative impacts on local biodiversity in the invaded regions of the Vindhyan highlands,India.The present study examines the effects of varied population densities of H.suaveolens on its vegetative trait performance,reproductive output,and density-dependent plant population regulations.Understanding the relationship between the population density and trait modulation ability of H.suaveolens at fine and coarse scales could help strategize for management.Methods The study was conducted in invaded habitats of H.suaveolens in the Vindhyan highlands,India.Population density was divided into low-,medium-,and high-density groups.Plant performance was assessed at two scales—fine scale and coarse scale.Plant performance traits,vegetative growth,and reproductive output were estimated as plant traits(Pl Ts)at the fine scale and patch traits(Pa Ts)at the coarse scale.The plasticity response index(PI)was also estimated among three population densities.Results Results showed that Pl Ts-vegetative and reproductive traits,such as plant height,biomass,and number of seeds,were significantly different across densities,with medium-density individuals showing maximum plant height and plant biomass and high-density individuals exhibiting a higher number of seeds per plant.Pa Ts analysis revealed that plant biomass per patch was similar for medium-and high-density populations,whereas the number of seeds per patch was similar in low-and medium-density populations.PI values revealed that Pl Ts showed low,medium,and high plastic responses,while Pa Ts exhibited low and high plastic responses.Conclusions The study concludes that H.suaveolens exhibits density-dependent plant population regulations.As population density increases,low-density populations grow more rapidly,resulting in denser populations.These populations can negatively impact recipient habitats and,if left unchecked,grow into high-density populations with higher seed production.The study suggests that low-density areas should be considered a high priority for developing efficient and cost-effective management strategies.The present study emphasizes the importance of incorporating Allee effects dynamics in invasion studies for predicting high-risk/priority areas for strategizing invasive species management.
基金funded by the United States Geological Survey Aquatic GAP Project
文摘Background Fluvial fish habitat in the Northeastern and Midwestern U.S. is substantially affected by natural landscape factors and anthropogenic stressors, with climate change expected to alter natural influences and exacerbate stressor effects. To conserve fluvial fish species in the future, it is crucial to understand which fish habitats will be most strongly influenced by changing climate, which species are most sensitive to climate change, and how changes in individual species will affect entire assemblages. To answer these questions, we modeled fluvial fish distributions under projected changes in climate to understand how climate could affect suitability of fish habitat for 55 widely distributed fluvial fishes with differing thermal preferences in the region. Using boosted regression tree models, we predicted distributions of fishes at a stream reach scale using four contemporary climate variables including annual mean air temperature, annual precipitation, and variation in monthly air temperature and precipitation along with seven natural landscape and anthropogenic stressor variables. We then used projected values from eight general circulation models(GCMs) during 2041–2080 to evaluate potential patterns in species richness, turnover, and range shifts under climate change across the study region.Results Most cold-water and cool-water species were projected to lose habitat;however, projected habitat loss also occurred for certain small-bodied warm-water species. The percentage change in species richness of all 55 species across reaches ranged from-40.4 to 33.93%, with regions of major species richness losses occurring across southern portions of the Northeastern coast and southern Midwest regions. Species turnover ranged from 0 to 43.5% with substantial turnover occurring along the Northeastern coast and upper Midwest.Conclusions Temperature and precipitation variation will influence fish species distribution substantially. Our findings provide multiple measures describing patterns of fish community change under climate change to aid management and conservation of stream fishes in the future.
文摘Background Describing where distribution hotspots and coldspots are located is crucial for any science-based species management and governance.Thus,here we created the world's first Super Species Distribution Models(SDMs)including all described primate species and the best-available predictor set.These Super SDMs are conducted using an ensemble of modern Machine Learning algorithms,including Maxent,Tree Net,Random Forest,CART,CART Boosting and Bagging,and MARS with the utilization of cloud supercomputers(as an add-on option for more powerful models).For the global cold/hotspot models,we obtained global distribution data from www.GBIF.org(approx.420,000 raw occurrence records)and utilized the world's largest Open Access environmental predictor set of 201 layers.For this analysis,all occurrences have been merged into one multi-species(400+species)pixel-based analysis.Results We present the first quantified pixel-based global primate hotspot prediction for Central and Northern South America,West Africa,East Africa,Southeast Asia,Central Asia,and Southern Africa.The global primate coldspots are Antarctica,the Arctic,most temperate regions,and Oceania past the Wallace line.We additionally described all these modeled hotspots/coldspots and discussed reasons for a quantified understanding of where the world's non-human primates occur(or not).Conclusions This shows us where the focus for most future research and conservation management efforts should be,using state-of-the-art digital data indication tools with reasoning.Those areas should be considered of the highest conservation management priority,ideally following‘no killing zones'and sustainable land stewardship approaches if primates are to have a chance of survival.
基金funded by the German Research Foundation(Project number:BA 5127/3-1)supported by the Czech Science Foundation(21-09334J)supported by the Ministry of Education,Youth and Sports of the Czech Republic(CZ.02.01.01/00/22_008/0004597)
文摘Background The decomposition of organic matter is among the most important ecosystem processes in forest ecosystems,regulating the carbon and nutrient cycle.However,our understanding about how direct(environment and decomposer diversity)and indirect effects(environment via decomposer diversity)contribute to deadwood decomposition is limited.We set up a large real-world deadwood experiment in a mixed mountain forest in southeastern Germany considering beech(Fagus sylvatica)and fir(Abies alba)as substrates.We simultaneously tested effects of canopy cover,amount and heterogeneity of surrounding deadwood and a broad set of fungal diversity measures mediated by environment on deadwood density loss after 10 years.Results Deadwood density loss was mainly explained by tree species and canopy cover.Beech showed higher density loss than fir and density loss was larger in open compared to closed canopies.Even though fungal diversity is mediated by environment,the direct effects on density loss were weak and inconsistent across tree species and fungal diversity measures.Conclusions We found weak support for the fungal diversity–ecosystem process relationship for deadwood decomposition.We suggest that deadwood decomposition and the resulting carbon and nutrient cycles in forest ecosystems are primarily regulated by the tree species selected through forest management and canopy disturbances,particularly in the context of climate change.
基金funded by the Deutsche Forschungsgemeinschaft(DFG,German Research FoundationCRC 1439/1,project number:426547801)
文摘Background The global freshwater biodiversity crisis has led to widespread implementation of measures to counteract environmental degradation and biodiversity loss.While these efforts aim to foster recovery,intensifying stressors continue to drive complex biotic responses,the trajectories and drivers of which are insufficiently understood.This study examines the roles of abiotic stressors,biotic interactions(e.g.,competition),and land use in shaping ecological status changes across Germany,using data from 1599 river sites sampled at least twice between 2004 and 2022.Results Changes in abiotic stressors emerged as the most consistent drivers of ecological status,explaining substantial variation(R^(2)=0.39)and similar slopes for recovery(β=-0.11)and degradation(β=-0.10).Biotic interactions,particularly interspecific competition,also influenced the ecological status(R^(2)=0.11),with stronger positive effects observed during recovery(β=2.99)compared to degradation(β=1.59).Land use effects varied by context:Streams in catchments with higher cropland or urban areas showed greater likelihood of recovery,whereas streams in forested catchments were more prone to degradation.These results highlight the interplay of abiotic and biotic factors in driving ecological processes of recovery and degradation.Conclusion These findings emphasize the critical role of improving water quality for enhancing biodiversity and ecological status in rivers,while also demonstrating the importance of biotic interactions and land use context in driving recovery dynamics.Integrating these insights into management and restoration efforts can enhance freshwater ecosystem resilience in the face of escalating environmental pressures.
基金funded by the National Key R&D Program of China[No.2024YFF1306600]the National Natural Science Foundation of China[31961143023]+3 种基金the Dinghushan Forest Ecosystem Positioning Research Station of the National Science and Technology Infrastructure Platformthe Chinese Ecosystem Research Network(CERN)the Operation Service Project of the National Scientific Observation and Research Field Station of the Dinghushan Forest Ecosystem of Guangdongthe Ministry of Science and Technology of the People’s Republic of China
文摘Background Subtropical forests play a critical role in global carbon cycling but are highly sensitive to climate-d riven precipitation and temperature variability.At China's Dinghushan Biosphere Reserve,observed warming(+1.5℃since 2002)and precipitation declines(8.2±1.3 mm/yr)exceed global subtropical averages,yet their combined effects on water-use efficiency(WUE)and carbon exchange remain poorly quantified.Methods Using 21 years of eddy covariance and meteorological data(2002-2022),we analyzed WUE(defined as NEE/ET;g C kg^(-1)H_(2)O)responses to drought events classified via the standardized precipitation index(SPI).Results The reserve experienced increasing drought frequency,with 7 extreme droughts(SPI≤-2.0)post-2010versus 2 pre-2010.Soil moisture extremes(<0.15 m^(3)m^(-3))reduced WUE by 2.35 g C kg^(-1)H_(2)O.Carbon fluxes showed diffe rential sensitivity:ecosystem respiration(RE)declined most sharply(-71.9×10^(-5)g C m^(-2)s^(-1))during extreme droughts,while gross primary productivity(GPP)exhibited non-linear reductions below a 1,200 mm yr^(-1)precipitation threshold.Late-successional forests maintained 0.94 g C kg^(-1)H_(2)O higher WUE than mid-successional stands during droughts,linked to deeper rooting systems(120±15 cm).The identified 3-year recovery lag suggests targeted reforestation during wet intervals(SPI≥1.5)could enhance resilience.Conclusion By establishing quantitative drought thresholds and revealing hydraulic versus non-hydraulic limitations,our findings provide actionable strategies for subtropical forest conservation under climate change.
基金Utah State University and the Utah Agricultural Experiment Station(Project 1711)
文摘Background Recent increases in tree mortality are often attributed to climate, but climate extremes may just be the last of many stressors that have unfolded over many years resulting in tree death. Potentially it is only those trees weakened by mechanical damage or attacks by insects or fungi that are susceptible to climate-mediated mortality, whereas vigorous trees resist periods of unfavorable climate. Although previous studies have explored immediate and catastrophic effects of mechanical damage via blowdowns and stem breakage, few have investigated the delayed effects of mechanical damage on mortality. Taxus is a shade-tolerant genus of subcanopy trees or shrubs distributed throughout the northern hemisphere. Populations of Taxus are in decline worldwide but owing to the tenacity of Taxus in the face of stressors, this decline is poorly understood. Here, we provide spatial evidence that cumulative stress interactions, particularly mechanical damage, contribute to Taxus mortality.Methods We examined 14 years of annual demographic data from the 27.2 ha Wind River Forest Dynamics Plot(WFDP), where woody stems, snags, and deadwood have been tagged, mapped and identified to species. We analyzed the multiple factors associated with tree death, including mechanical damage, pathogens, suppression, beetles, animal damage, and their combinations. We performed spatial pattern analyses with the pair correlation function to investigate the prevalence of density-dependent mortality, effects of neighboring large-diameter trees, and effects of nearby snag fall and deadwood.Results In 2011, there were 29,827 trees within the WFDP of which 2119 were Taxus. Between 2011 and 2024, Taxus declined to 1523 trees(mean annual mortality of 2.79% yr^(-1)). Taxus mortality was not influenced by intraspecific density dependence or the presence of snags but was mainly driven by mechanical damage, pathogens, and suppression. Dead Taxus were strongly associated with deadwood within 2 m of the bole. Structural equation modeling showed that mechanical damage likely increased the vulnerability of Taxus to pathogen infection and exposure to drier gap areas.Conclusions These results suggest that Taxus mortality is rarely due to a single event, but a cumulative process of interacting stressors initiated by falling wood and often culminating in death by other stressors—potentially many years later. The association of newly dead trees with deadwood suggests that falling snags likely contributed to past crown damage, initiating or accelerating a decline spiral. The results emphasize that previous mechanical damage—evidenced by mapped and persistent deadwood—can disproportionately affect tree species, influencing successional dynamics.
基金the Swiss University Conference and the ETH Board within the project Swiss Earth Observatory Network(SEON)the State Secretariat for Education and Research(project number C04.0255,Switzerland)the SNF for the COCO project(200021_197357)
文摘Background Forest ecosystems are in the spotlight for their potential to mitigate anthropogenic carbon dioxide(CO_(2)) emissions through net photosynthesis. However, this mitigation potential can be counteracted by respiratory losses, e.g., from soils and the forest floor. With global warming, soil respiration(SR) rates are expected to increase, unless acclimation occurs. Using manual and automated chambers as well as a below-canopy eddy-covariance system, we quantified SR and forest floor net CO_(2) exchange(NEEff) for 13 years throughout an 18-year study period(2006–2010, 2015–2016, 2018–2023) in a mixed deciduous forest ecosystem in Switzerland. We identified the contribution of environmental drivers for SR and NEEff using Extreme Gradient Boosting models and Shapley additive explanations(SHAP) analyses and assessed the long-term temperature sensitivity of SR and NEEff.Results Over the 18-year study period, soil temperature increased significantly and was the main driver of both SR and NEEff, explaining over 50% of their temporal variability. Differences in drivers and magnitudes of SR vs. NEEff were only found in early spring, when the forest floor vegetation showed net CO_(2) uptake. Finally, we found no evidence that SR or NEEff(at mean annual temperatures) had increased between 2006 and 2023. Similarly, no significant change in the temperature sensitivity of SR and NEEff was observed.Conclusions Combining multiple techniques to assess long-term responses of CO_(2) fluxes to environmental conditions with machine learning approaches enhanced our understanding of forest responses to climate change. Moreover, our findings suggest that soil and forest floor respiration already acclimated to warmer conditions, highly relevant for predicting future mitigation potentials of forest ecosystems.
基金supported by the National Natural Science Foundation of China(32130013)the National Key Research and Development Program of China(2022YFC2601601)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK05010112,2019QZKK0304-02)Dynamic Monitoring of Distribution,Quantity and Activity of Typical Large and Medium-sized Mammals in the Yarlung Tsangpo River Basin(54000022T000000071200)the Institute of Zoology,Chinese Academy of Sciences(2023IOZ0104)
文摘Background Identifying the processes that govern community assembly along elevational gradients has been a central theme in ecology,especially in montane ecosystems where abundant species and strong turnover are present.However,our understanding of how the relative importance of deterministic and stochastic processes varies along elevational gradients remains limited.Here,we compiled a rigorously curated dataset of elevational distributions of 734 breeding bird species across the Hengduan Mountains in China to assess the dominant underlying mechanisms of bird community assembly at both intra-community and inter-community scales across four elevation zones:low,middle,subalpine,and alpine.Results At the intra-community scale,homogeneous dispersal played a pivotal role in driving community assembly of breeding birds across the Hengduan Mountains.Deterministic processes became more influential with increasing elevation,whereas stochastic processes prevailed in low,middle,and subalpine zones.At inter-community scale,assemblages from different elevation zones were more differentiated by dispersal limitation.Non-Passeriformes experienced more obvious influence of homogeneous dispersal but were less subject to dispersal limitation compared to Passeriformes.Conclusions Our findings highlight the role of stochastic processes in shaping biotic communities in montane ecosystems,but this effect is scale-dependent.The transition from stochastic to deterministic processes along elevational gradients suggests that environmental factors become more influential at higher elevations.Species dispersal ability may affect the relative importance of these two processes shaping community assembly.
基金funded through the internal funds of the ICMR-VCRC,Puducherry,India
文摘Background Tick borne diseases are re-emerging around the world,including India.Information about the occurrence of the tick vectors in different geographical locations is essential for controlling the diseases.Tick surveys have not been conducted in many parts of India and information on the current prevalence of tick vectors is not available in all states of India.Many studies have been carried out utilizing modelling methods to predict the distribution of tick species in other countries.The MaxEnt model is widely used for predicting tick species distribution using bioclimatic variables.Lyme disease vectors such as Ixodes sp.,Amblyomma sp.,and Dermacentor sp.are the most commonly predicted tick species.However,very few studies have been carried out to predict the distribution of tick species in India.Haemaphysalis spinigera,the primary Kyasanur Forest Disease vector,was predicted along the Western Ghats using the MaxEnt model.Rhipicephalus(Boophilus)microplus was predicted across India using the generalized linear model(GLM).Identifying the tick vectors in transmitting the infection through conventional survey and identification methods is cumbersome due to the less number of experienced persons available.Prediction of tick vectors of public health concern,including other tick species in different geographical regions of Tamil Nadu,India,is essential for the prevention and control of tick-borne disease in humans and domestic animals.The present study adopts the package‘SSDM’(stacked species distribution models)with R software containing ensemble species distribution models to predict the distribution of tick species using different available environmental and climatic data.Results The categorical variables such as land use and land cover(LULC),soil type,elevation,Bio1,Bio10,Bio15,Bio19 and Bio8 contributed more to modelling the distribution of tick species.MaxEnt,GLM,GBM and GAM are suitable models for predicting the tick species distribution in the present study.Among these models,MaxEnt is the most suitable model for predicting tick species distribution in Tamil Nadu,India.Conclusions Our results suggest that MaxEnt is a suitable model for predicting the distribution of tick species.Both environmental factors such as LULC,elevation and soil type and bioclimatic factors such as temperature and precipitation contribute significantly to predicting tick species distribution in domestic animals in Tamil Nadu.The SSDM package is very useful and user-friendly graphical user interface for modelling the distribution of tick species.However,the package can be further improved by using higher resolution raster variables in larger areas,which is not currently supported.The predicted elevation range of Ha.spinigera distribution could not be provided due to software limitations.
基金the National Natural Science Foundation of China (No. 32271654)the Natural Science Foundation of Sichuan (No. 2024NSFSC0010)GDAS’ Project of Science and Technology Development (No. 2023GDASZH-2023010104–1)
文摘Background Deforestation for terraced orchards,a common agricultural development pattern in mountainous ecosystems,drastically modifies soil physicochemical and biological properties.This conversion can affect soil microbial carbon use efficiency(CUE),which is a crucial indicator of soil carbon dynamics.However,the impact of this conversion on CUE remains unclear.Understanding how deforestation affects CUE will help predict soil carbon dynamics and guide the development of sustainable ecosystem strategies in fragile mountainous areas.Methods Herein,the response of CUE to environmental variations induced by deforestation for terraced orchards in an arid valley was explored.We quantified CUE using the^(18)O-labeled water addition method.To identify the underlying driving factors,soil properties and microbial parameters were measured concurrently.Results Microbial CUE declined significantly after forest conversion to terraced orchards.Multiple factors,including soil micro-environmental conditions,stoichiometric traits,enzymatic properties,and microbial community attributes,were all closely associated with CUE.Furthermore,hierarchical partitioning analysis revealed soil stoichiometric traits as the primary drivers of CUE reduction,especially traits associated with the C:N and C:P ratios.During the conversion process,mechanical compaction and horizon inversion increased soil bulk density and clay content,thereby reducing soil aeration.These micro-environmental constraints were closely linked to intensified imbalances in the C:N and C:P ratios between microbes and soil.Along with the reduced soil C:N ratio,these stoichiometric shifts made it more difficult for microorganisms to obtain resources.Therefore,microbial C limitation intensified,soil microbes shifted from being primarily limited by P in forests to being co-limited by C and P in terraced orchards,which in turn stimulated greater microbial investment in resource-acquiring hydrolytic enzymes.Consequently,CUE declined because microbial growth decreased more significantly than microbial respiration.Conclusion In summary,deforestation for terraced orchards in the arid valley reduced CUE by constraining soil micro-environments and resource conditions.These findings advance our understanding of CUE variations following deforestation and have important implications for soil carbon cycling in vulnerable mountain ecosystems.
基金a Project(WAMOS)funded by the Austrian Promotion Agency(FFG)within the program line“ASAP”(Project Number FO999900575)
文摘Background The impact of vessel-induced waves on macrophyte communities in lakes remains controversial,due to a lack of comprehensive assessments which also consider mechanistic effects on ecological processes during early life stages.This study investigates both the direct and indirect effects of such waves on the early life stages of macrophytes in a case study of Lake W?rthersee,Austria.The study focuses on Characeae species and Najas intermedia which have both experienced significant declines in Lake W?rthersee.Results The linear wave theory was applied to model typical small vessel-induced waves,characterized by wave heights of 0.05–0.30 m and periods of 1 and 3 s.Relevant characteristics for testing remobilization of oospores and seeds like geometric dimensions and density were experimentally determined by field data.Sediment samples from ten locations across six beach sites at depths ranging from 0.8 to 2.2 m were collected and analyzed for oospore presence and sediment texture.Results indicate that maximum wave scenarios can affect oospores and seeds directly by motion activation at water depths down to 3.75 m.Moderate wave scenarios,which are assumed to occur more frequently,can mobilize those particles between 0.75 and 2.25 m water depth.This corresponds to our field data,where 95%of oospores were found in samples from water depths≥2 m.The mobilization disrupts germination processes and impedes the recovery of macrophyte populations.Additionally,in the study lake and other fine-sediment dominated lakes,a significant fraction of sediments can be initiated to motion by small vessel-induced waves,which may indirectly affect germination by altering habitat conditions like turbidity and nutrients.However,grain size distribution showed minimal variation with depth at the same sampling sites,indicating limited sediment redistribution at the selected sampling sites by small vessel-induced waves.No significant correlation was found between oospore abundance and sediment grain size.Conclusions These findings suggest that the impacts of increased traffic of small vessels in lakes may be a key factor contributing to the decline of macrophyte species in shallow waters by motion triggering of oospores and seeds,with broader implications for the recreational management.
