Species’ geographical range, environmental range and traits lead to specimen collection preference of dominant plant species of grasslands in Northern China

Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection in China is preferred by species traits(i.e.,plant height,flowering and fruiting period),environmental range(i.e.,the temperature and precipitation range)and geographical range(i.e.,distribution range and altitudinal range).Ordinary least squares models and phylogenetic generalized linear mixed models were used to analyze the relationships between specimen number and the explanatory variables.Random Forest models were then used to find the most parsimonious multivariate model.The results showed that interannual variation in specimen number between 1900 and 2020 was considerable.Specimen number of these species in southeast China was notably lower than that in northwest China.Environmental range and geographical range of species had significant positive correlations with specimen number.In addition,there were relatively weak but significant associations between specimen number and species trait(i.e.,plant height and flowering and fruiting period).Random Forest models indicated that distribution range was the most important variable,followed by flowering and fruiting period,and altitudinal range.These findings suggest that future floristic surveys should pay more attention to species with small geographical range,narrow environmental range,short plant height,and short flowering and fruiting period.The correction of specimen collection preference will also make the results of species distribution model,species evolution and other works based on specimen data more accurate.

Rapid loss of leguminous species in the semi-arid grasslands of northern China under climate change and mowing from 1982 to 2011

Effects of mowing on the composition and diversity of grasslands varied with climate change(e.g.,precipitation and temperature).However,the interactive effects of long-term mowing and climate change on the diversity and stability of leguminous and non-leguminous species in the semi-arid grasslands are largely unknown.Here,we used in situ monitoring data from 1982 to 2011 to examine the effects of continuous mowing and climate change on the plant biomass and diversity of leguminous and non-leguminous species,and soil total nitrogen in the typical semi-arid grasslands of northern China.Results showed that the biomass and diversity of leguminous species significantly decreased with the increasing in the biomass and diversity of non-leguminous species during the 30-a period.Variations in biomass were mainly affected by the long-term mowing,while variations in diversity were mainly explained by the climate change.Moreover,the normalized change rates of diversity in leguminous species were significantly higher than those in non-leguminous species.Mowing and temperature together contributed to the diversity changes of leguminous species,with mowing accounting for 50.0%and temperature 28.0%.Temporal stability of leguminous species was substantially lower than that of non-leguminous species.Consequently,soil total nitrogen decreased in the 2000s compared with the 1980s.These findings demonstrated that leguminous species were more sensitive to the long-term mowing and climate change than non-leguminous species in the semi-arid grasslands.Thus,reseeding appropriate leguminous plants when mowing in the semi-arid grasslands may be a better strategy to improve nitrogen levels of grassland ecosystems and maintain ecosystem biodiversity.

Assessing the collapse risk of Stipa bungeana grassland in China based on its distribution changes

The criteria used by International Union for Conservation of Nature(IUCN) for its Red List of Ecosystems(RLE) are the global standards for ecosystem-level risk assessment, and they have been increasingly used for biodiversity conservation. The changed distribution area of an ecosystem is one of the key criteria in such assessments. The Stipa bungeana grassland is one of the most widely distributed grasslands in the warm-temperate semi-arid regions of China. However, the total distribution area of this grassland was noted to have shrunk and become fragmented because of its conversion to cropland and grazing-induced degradation. Following the IUCN-RLE standards, here we analyzed changes in the geographical distribution of this degraded grassland, to evaluate its degradation and risk of collapse. Past(1950-1980) distribution areas were extracted from the Vegetation Map of China(1:1,000,000). Present realizable distribution areas were equated to these past areas minus any habitat area losses. We then predicted the grassland’s present and future(under the Representative Concentration Pathway 8.5 scenario) potential distribution areas using maximum entropy algorithm(MaxEnt), based on field survey data and nine environmental layers. Our results showed that the S. bungeana grassland was mainly distributed in the Loess Plateau, Hexi Corridor, and low altitudes of the Qilian Mountains and Longshou Mountain. This ecosystem occurred mainly on loess soils, kastanozems, steppe aeolian soils and sierozems. Thermal and edaphic factors were the most important factors limiting the distribution of S. bungeana grassland across China. Since 56.1% of its past distribution area(4.9×10~4 km^2) disappeared in the last 50 a, the present realizable distribution area only amounts to 2.2×10~4 km^2. But only 15.7% of its present potential distribution area(14.0×10~4 km^2) is actually occupied by the S. bungeana grassland. The future potential distribution of S. bungeana grassland was predicted to shift towards northwest, and the total area of this ecosystem will shrink by 12.4% over the next 50 a under the most pessimistic climate change scenario. Accordingly, following the IUCN-RLE criteria, we deemed the S. bungeana grassland ecosystem in China to be endangered(EN). Revegetation projects and the establishment of protected areas are recommended as effective ways to avert this looming crisis. This empirical modeling study provides an example of how IUCN-RLE categories and criteria may be valuably used for ecosystem assessments in China and abroad.

Sensitivity of livelihood strategy to livestock production and marketization:An empirical analysis of grasslands in Inner Mongolia,China

Recent researches have primarily focused on the relationship between livelihood strategies and livelihood capital,with few empirical studies on the sensitivity of livelihood strategies to livestock production and marketization in Inner Mongolia Autonomous Region of China.This study used an income distribution approach to categorize livelihood strategies of the respondents(n=394)into three types,i.e.,herder livelihood strategy(LS1),petty-herder livelihood strategy(LS2),and non-herder livelihood strategy(LS3).Using the multinomial logistic regression model,we compared livestock production and marketization across the three livelihood strategies.Our findings showed that(1)livestock production and marketization tended to favor LS1;(2)an increase in the land asset(contracted and rented grassland)and off-take rate increased the probability of households choosing LS1;(3)stocking rate was higher for LS1;and(4)the higher critical market-related risks perceived by herders were animal price and hay and corn price.Moreover,higher livestock price acted as a deterrent to diversifying into other livelihood strategies(LS2 and LS3).Finally,this study advocates for policies that will promote the land transfer market,adopt modern techniques in animal husbandry,improve the medium for disseminating market information to herders,and provide incentives for long-term livelihood transformation.

Bird specimen number linked with species trait and climate niche breadth

Biological specimens are fundamental for taxonomy and flora/fauna research.More importantly,they also play crucial roles in recording environmental impacts on morphology and behavior,which is vital for biodiversity research and conservation.However,there are few systematic studies on the patterns and drivers of bird specimen number at regional scales.This study is the first attempt to examine the relationships between bird specimen number and species traits as well as climate niche breadth in China,aiming to answer two questions:1)how do species’temperature niche breadth and precipitation niche breadth influence specimen number?2)which trait is most associated with bird specimen number?The associations between bird specimen number and explanatory variables were examined using ordinary least squares,generalized linear models,phylogenetic generalized linear mixed models,and multiple comparisons.The results showed that Muscicapidae was the family with the highest specimen number,and Passeriformes was the order with the highest specimen number.Bird specimen number significantly increased with larger temperature niche breadth and precipitation niche breadth.Specimen number was also positively associated with geographic range size,habitat specificity,hunting vulnerability and clutch size,but negatively associated with body size.These findings suggest that future bird specimen collection should pay more attention to birds with limited ecological niches,large body sizes,and small clutch sizes.This research enhances the use of bird specimen data to study and preserve biodiversity.

Nitrogen addition and mowing alter drought resistance and recovery of grassland communities

Nitrogen enrichment and land use are known to influence various ecosystems,but how these anthropogenic changes influence community and ecosystem responses to disturbance remains poorly understood.Here we investigated the effects of increased nitrogen input and mowing on the resistance and recovery of temperate semiarid grassland experiencing a three-year drought.Nitrogen addition increased grassland biomass recovery but decreased structural recovery after drought,whereas annual mowing increased grassland biomass recovery and structural recovery but reduced structural resistance to drought.The treatment effects on community biomass/structural resistance and recovery were largely modulated by the stability of the dominant species and asynchronous dynamics among species,and the community biomass resistance and recovery were also greatly driven by the stability of grasses.Community biomass resistance/recovery in response to drought was positively associated with its corresponding structural stability.Our study provides important experimental evidence that both nitrogen addition and mowing could substantially change grassland stability in both functional and structural aspects.Our findings emphasize the need to study changes across levels of ecological organization for a more complete understanding of ecosystem responses to disturbances under widespread environmental changes.

Endemic medicinal plant distribution correlated with stable climate,precipitation,and cultural diversity

Medicinal plants provide crucial ecosystem services,especially in developing countries such as China,which harbors diverse endemic medicinal plant species with substantial cultural and economic value.Accordingly,understanding the patterns and drivers of medicinal plant distribution is critical.However,few studies have investigated the patterns and drivers of endemic medicinal plants distribution in China.Here,we linked endemic medicinal plants distribution with possible explanatory variables,i.e.,paleoclimate change,contemporary climate,altitudinal range and ethnic minority human population size at the prefecture city level in China.Our results show that endemic medicinal plants are concentrated in southern China,especially in southwestern China.Notably,both endemic medicinal plant species richness and the ratio of endemic medicinal plant species richness are negatively associated with glacialinterglacial anomaly in temperature,and positively associated with contemporary precipitation and altitudinal range.In addition,we found that endemic medicinal plant species richness is positively associated with ethnic minority population sizes as well as its ratio to the overall population size.These findings suggest that the distribution of endemic medicinal plants is determined by multiple drivers.Furthermore,our findings stress that dramatic future climate changes and massive anthropogenic activities in southern China pose great challenges to the conservation of China's endemic medicinal plants.

Precipitation is the dominant driver for bird species richness,phylogenetic and functional structure in university campuses in northern China

Background:Although urbanization is threatening biodiversity worldwide,the increasing green urban spaces could harbor relatively high biodiversity.Therefore,how to maintain the biodiversity in urban ecosystem is crucial for sustainable urban planning and management,especially in arid and semiarid regions with relatively fragile environment and low biodiversity.Here,for the first time we linked species richness,phylogenetic and functional structure of bird assemblages in university campuses in northern China with plant species richness,glacial-interglacial climate change,contemporary climate,and anthropogenic factors to compare their relative roles in shaping urban bird diversity.Methods:Bird surveys were conducted in 20 university campuses across Inner Mongolia,China.Ordinary least squares models and simultaneous autoregressive models were used to assess the relationships between bird species richness,phylogenetic and functional structure with environmental factors.Structural equation models were used to capture the direct and indirect effects of these factors on the three components of bird diversity.Results:Single-variable simultaneous autoregressive models showed that mean annual precipitation was consistently a significant driver for bird species richness,phylogenetic and functional structure.Meanwhile,mean annual temperature and plant species richness were also significant predictors for bird species richness.Conclusions:This study suggests that campuses with warmer and wetter climate as well as more woody plant species could harbor more bird species.In addition,wetter campuses tended to sustain over-dispersed phylogenetic and functional structure.Our findings emphasize the dominant effect of precipitation on bird diversity distribution in this arid and semiarid region,even in the urban ecosystem.

High-resolution remote sensing data can predict household poverty in pastoral areas,Inner Mongolia,China

The accurate prediction of poverty is critical to efforts of poverty reduction,and high-resolution remote sensing(HRRS)data have shown great promise for facilitating such prediction.Accordingly,the present study used HRRS with 1 m resolution and 238 households data to evaluate the utility and optimal scale of HRRS data for predicting household poverty in a grassland region of Inner Mongolia,China.The prediction of household poverty was improved by using remote sensing indicators at multiple scales,instead of indicators at a single scale,and a model that combined indicators from four scales(building land,household,neighborhood,and regional)provided the most accurate prediction of household poverty,with testing and training accuracies of 48.57%and 70.83%,respectively.Furthermore,building area was the most efficient indicator of household poverty.When compared to conducting household surveys,the analysis of HRRS data is a cheaper and more time-efficient method for predicting household poverty and,in this case study,it reduced study time and cost by about 75%and 90%,respectively.This study provides the first evaluation of HRRS data for the prediction of household poverty in pastoral areas and thus provides technical support for the identification of poverty in pastoral areas around the world.

Kin recognition benefits clonal offspring performance of historically grazed Leymus chinensis:insights for grassland management

Background:Individual plants can identify their neighbors and adjust their biomass investment to avoid competing with their relatives or jointly cope with external stresses.Maternal effects can improve their offspring adaptability under external stresses.However,how grazing-induced maternal effects influence plant kin interactions remain unknown.Methods:Clonal offspring of Leymus chinensis grown under multi-year grazing and non-grazing conditions were used for this study.A greenhouse experiment was conducted to evaluate the performance of focal plants in the presence of kin and stranger neighbors,with the aim of analyzing the interaction between maternal effect and kin relatedness.Results:Kin relatedness of neighboring plants affected the biomass production and allocation of focal plants,demonstrating the presence of kin recognition in L.chinensis.Moreover,grazing-induced maternal effects significantly enhanced kin recognition in the species.Consequently,the presence of stranger neighbors significantly improved the growth potential of grazed offspring.Specifically,the total biomass of clonal offspring increased by 73.1%compared to the kin group,potentially buffering grazing-induced plant productivity declines.Conclusions:This study shows that historical grazing enhances kin recognition in L.chinensis.Thus,introducing multi-genotypic plants can increase the productivity of grasslands.The findings of this study enhance our understanding of intraspecific plant–plant interactions in clonal species and provide new insights into sustainable grassland management.

More endemic birds occur in regions with stable climate, more plant species and high altitudinal range in China

Background:Geographical distribution of endemic species and its multiple scale drivers are an important topic in biodiversity conservation,because these species are especially vulnerable to climate change and habitat degradation,and therefore have high conservation priority.Here,for the first time,we simultaneously linked glacial-interglacial climate change,contemporary climate,plant species richness and altitudinal range with endemic bird distribution in China.Methods:Ordinary least squares models and simultaneous autoregressive models were used to assess the associations between endemic bird richness,endemic bird ratio and each explanatory variable.Structural Equation Models were also performed to test the direct and indirect effects of these variables on endemic bird richness and endemic bird ratio.Results:Higher endemic bird richness and endemic bird ratio occurred in regions with stable glacial-interglacial temperature,i.e.,southwest China.Plant species richness and altitudinal range were also positively correlated with endemic bird richness and endemic bird ratio.Glacial-interglacial temperature change,contemporary precipitation,plant species richness and altitudinal range were all included in the best combination of variables for endemic bird richness.Importantly,glacial-interglacial temperature change had strong direct effects on both endemic bird richness and endemic bird ratio,while plant species richness only had a direct effect on endemic bird richness.Conclusions:Our results indicate that endemic birds in China concentrate in southwest regions where there are stable glacial-interglacial temperature,more plant species and larger altitudinal range.Notably,while stable climate has strong direct effects on both endemic bird richness and endemic bird ratio,plant species may affect endemic bird richness through its effect on overall bird species richness.Importantly,the recent anthropogenic activities have also significantly intensified in this region,which would pose huge challenge for biodiversity conservation in China.

养分回收加剧了氮沉降背景下盐渍化草地优势植物内在氮磷的失衡

在落叶之前,从衰老组织中重新吸收养分被认为是植物适应养分缺乏的一种策略。然而,养分重吸收如何调节植物体内氮(N)和磷(P)的平衡仍不清楚,特别是在土壤氮有效性增加的情况下。本文研究了不同速率(0、1、2、4、8、16、24和32 g N m^(-2)yr^(-1))氮添加对中国北方盐渍化草地优势植物赖草(Leymus secalinus)叶片和茎秆养分回收的影响,以及养分回收在调控植物内部氮磷平衡的作用。研究结果表明:氮添加6年后,随着施氮量的增加,绿色和衰老组织(叶和茎)的N浓度和氮磷比均呈上升趋势。随着施氮量的增加,绿色组织中P浓度降低,而衰老组织中P浓度无显著变化。N重吸收效率(NRE)、P重吸收效率(PRE)和NRE:PRE比值沿N添加梯度显著降低。此外,我们发现衰老组织(叶和茎)氮磷比比绿色组织(叶和茎)氮磷比对氮素添加的响应更敏感,植物内在氮磷失衡的加剧主要是由于不成比例的减少养分重吸收,尤其是NRE。总的来说,我们的研究表明,NRE和PRE的差异进一步加剧了植物凋落物内部氮磷的失衡。

The shift in the abundance of two Stipa species in response to land use change is associated with their divergent reproductive strategies

Aims The divergent changes of plant species under land use changes are key mechanisms underlying vegetation succession.Stipa grandis steppe and Stipa krylovii steppe are two plant commu-nities widely distributed on the Mongolian Plateau.They have been speculated to be able to succeed into each other under different land use types and intensities based on the observa-tions on their presence and abundance at the sites with dif-ferent land use history.However,no direct evidence,neither the underlying mechanisms,have been reported for this specu-lation.Here,we verified this speculation and explored the underlying mechanisms in the typical steppe region of Inner Mongolia.Methods We investigated the abundance and reproductive behavior of S.kry-lovii and S.grandis under different land use types and intensities.We used 18 grassland paddocks to run a 6-year experiment with 6 management treatments(T0-unused,T1-grazing monthly in plant growing season,T2,T4,T6-grazing in different months in plant growing season,and T8-mowing)replicated three times.We measured the relative density and cover of S.krylovii and S.grandis using line sampling method and examined their number and bio-mass of vegetative and reproductive tillers using quadrat method in each paddock after treatments for 4 and 6 years.We also de-termined these plant attributes in 14 pairs of heavily versus lightly used grassland plots in a wide area(150 km×200 km)of the typical steppe region.Important Findings 1.Grazing largely and mowing moderately decreased the density ratio and coverage ratio of S.grandis to S.krylovii in grasslands(P<0.05),and the differences in these ratios between grazed and unused grasslands increased with time.2.Grazing,but not mowing,significantly enhanced the relative density(N_(rep)=reproductive tiller number/total tiller number)of,and biomass allocation(B_(rep)=reproductive tiller biomass/total bio-mass)to,reproductive tillers of S.krylovii(P<0.05),but not S.gran-dis.This grazing enhancement to sexual reproduction of S.krylovii,and additionally inhibition to N_(rep) of S.grandis(P<0.05),were found across the 14 pairs of heavily versus lightly used plots.3.Seasonal pattern of grazing affected sexual reproduction of S.kry-lovii.The N_(rep) and B_(rep) was higher under grazing in July and September(T4)than in July and August(T6)or in May and July(T2)(P<0.05),suggesting a relatively positive effect of grazing on sexual reproduction in July(tasseling phenophase)than in May or August.Our results provide direct evidence to the reciprocal change of S.grandis and S.krylovii in steppe communities under different management and indicate that gazing or mowing enhancement of sexual reproduction of S.krylovii relative to S.grandis is one of the mechanisms for the change.

季节性放牧改变大针茅养分回收和根系养分储存并影响其翌年春季返青生长

秋季养分回收是草地多年生植物保存和高效利用养分的关键机制。放牧对植物养分回收的影响可能改变根系养分储存,进一步影响植物在翌年春季的返青生长。多数研究关注于放牧草地植物养分回收和保存,而其对植物在翌年春季返青生长的影响研究则较少。本研究以半干旱草原多年生优势禾草——大针茅(Stipa grandis)为模式植物,具体评估了4种季节性放牧管理下(不放牧、春季放牧、夏季放牧和秋季放牧)大针茅植株水平的养分回收特征(养分回收度、回收效率和回收通量)、根系养分动态,以及翌年植物返青状况,旨在探究植物养分回收、根系养分储存和翌年返青生长对不同季节放牧的响应。研究结果显示,(i)大针茅氮回收效率为51%–66%、磷回收效率为58%–80%,养分回收通量在秋季放牧下最低,在春季放牧下最高。(ii)大针茅根系养分储存特征在夏季放牧下显著降低,在春季放牧下轻微下降,而在秋季放牧下则无变化。(iii)翌年春季大针茅返青生长状况在早春放牧下最佳,在秋季放牧下最差,这一现象主要受土壤水分的影响,而与根系养分储存无关。本研究为深入了解植物养分循环过程,建立草原保护和合理放牧管理制度提供了理论依据。

放牧和刈割对内蒙古典型草原植物养分的不同影响

放牧和刈割管理是天然草原的两种主要利用方式。放牧和刈割分别通过粪尿归还和养分移除的形式影响草原生态系统养分循环。植物养分对草原生态系统养分循环具有敏感的响应。然而,放牧和刈割管理在植物器官水平、种群和群落水平对植物养分具有怎样的影响,目前还缺乏准确的认知。我们在内蒙古半干旱草原地区通过野外控制实验探究持续放牧和轮牧以及低频率刈割和高频率刈割对草原生态系统的影响,并对不同处理下植物群落特征进行调查以及群落优势物种碳、氮和磷浓度进行测定。结果表明,(i)在持续放牧和轮牧下随放牧强度的增加,群落高度和地上现存量显著降低;每年一次刈割处理显著降低群落高度和地上现存量;(ii)在两种放牧制度下随放牧强度的增加,植物地上部分碳浓度显著降低,而氮、磷浓度则显著提高;不同刈割制度对植物地上部分碳、氮、磷浓度无显著影响;(iii)在两种放牧制度下随放牧强度的增加,植物群落碳、氮、磷库显著降低;不同刈割制度对植物群落碳、氮、磷库无显著影响;(iv)两种放牧下随放牧强度的增加,植物根系碳、氮、磷浓度无显著变化;两种刈割制度下植物根系碳、氮、磷浓度无显著变化,表明植物根系养分对外界干扰具有相对较高的稳定性和滞后性。本研究从多角度阐明了放牧和刈割管理对草原生态系统养分循环的影响。

去叶时间对半干旱草原植物养分回收和干草生产的影响

养分回收是植物养分保存的重要策略,其对环境和管理变化的响应关系到生态系统的养分循环和生产。去叶(刈割)是影响草地植物养分回收和生产的重要途径,而去叶时间的影响尚不清楚。本研究以内蒙古典型草原生态系统为对象,设置早期去叶(生物量高峰期之前)、峰期去叶(生物量高峰期)、晚期去叶(养分回收开始后)和不去叶(对照)4个处理,探讨了去叶时间对植物养分回收和生产的影响。通过测定植物物种和群落水平氮(N)和磷(P)回收特征,量化了植物N、P回收通量以及凋落物归还通量和干草输出通量,并评估了不同去叶时间处理下割草草地系统干草产量和质量。研究结果显示,峰期和晚期去叶降低植物群落N、P回收度,而早期去叶则对二者无影响;不同去叶时间处理下植物N、P回收效率相对稳定,仅晚期去叶降低N回收效率。峰期和晚期去叶降低植物群落N、P回收通量和凋落物N、P归还通量,而早期去叶并不影响这些参数。去叶时间降低植物群落养分回收通量,但未改变植物根系养分储存,说明根系养分吸收增加可补偿养分回收通量的降低。草地干草产量和质量在峰期去叶处理下最高,晚期去叶处理下最低。本研究结果为割草草地生态系统养分循环提供了新见解,通过调整刈割时间可以平衡草原的保护与生产,在植物生物量高峰期之前割草可实现保护和可持续生产的双重目标。

植物功能群在调控气候和土壤因子对蒙古高原草原群落物种丰富度和生物量影响中的作用

植物功能群组成主要受环境因素驱动,同时植物功能群组成也是影响草地生物多样性和生产力的主要因素之一。因此,理解植物功能群在调控环境因素对生态系统功能和生物多样性影响中可能发挥的作用至关重要。通过对蒙古高原草原65个样点的植物生物量和物种丰富度的调查,将157种多年生草本植物分为两种植物功能群(即禾草和杂类草)。通过随机森林模型和普通最小二乘回归,确定与植物功能群物种丰富度和地上生物量显著相关的环境因素(即干燥度、土壤总氮和pH),并利用结构方程模型探讨筛选出的环境因素与群落物种丰富度和生物量间的关系,以及植物功能群在驱动这种关系中发挥的作用。干燥度与禾草、杂类草以及整个群落的地上生物量和物种丰富度均呈显著的单峰关系。所有的物种丰富度和生物量指标均与土壤总氮和pH值显著相关。禾草在维持蒙古高原草原生态系统群落生物量中起着关键作用,并受气候因素的直接影响。而杂类草物种丰富度决定了群落总丰富度,并受到土壤因素直接的调控。因此,群落组成在调控环境因素对群落生物量和植物多样性的影响中起着关键作用。