Responses and feedback of litter properties and soil mesofauna to herbaceous plants expansion into the alpine tundra on Changbai Mountain, China

Shifts in alpine tundra plant species have important consequences for biodiversity and ecosystem services. However, recent research on upward species shifts have focused mainly on polar and high-latitude regions and it therefore remains unclear whether such vegetation change trends also are applicable to the alpine tundra at the southern edges of alpine tundra species distribution. This study evaluated an alpine tundra region within the Changbai Mountains, China, that is part of the southernmost alpine tundra in eastern Eurasia. We investigated plant species shifts in alpine tundra within the Changbai Mountains over the last three decades (1984–2015) by comparing contemporary survey results with historical ones and evaluated potential changes in the distribution of dwarf shrub and herbaceous species over the next three decades (2016–2045) using a combination of observations and simulations. The results of this study revealed that the encroachment of herbaceous plants had altered tundra vegetation to a significant extent over the last three decades, especially within low and middle alpine tundra regions in Changbai Mountains, China. The herbaceous species would continue shifting upward and expanding while their dwarf shrub counterparts would continue shifting upward and shrinking over the next three decades under the RCP 4.5 and RCP 8.5 scenarios. The upward shifts of plant species would not keep up with the rate of climate warming under the RCP 8.5 scenarios. The dominant plant tundra species may transform from dwarf shrubs to herbaceous varieties. The results of this study provide a scientific basis for biodiversity protection under climate change and a reference data set for additional research on alpine vegetation dynamics.

PDF HTML阅读 XML下载 导出引用 引用提醒 长白山苔原带凋落物生态化学计量特征及其对模拟氮沉降的响应 DOI: 10.5846/stxb202110212976 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41571078） Response of chemical composition and ecological stoichiometric characteristics of three types of litter to simulated nitrogen deposition in the Changbai Mountain tundra Author: Affiliation: Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:长白山苔原是我国乃至欧亚大陆东部独有的高山苔原，根据前人调查植被以灌木苔原为主要类型。在全球变暖背景下，近30年来，长白山岳桦林下的草本植物侵入苔原带，原生灌木苔原分化为灌木苔原、灌草苔原和草本苔原，形成了灌木、灌草混合和草本3种不同类型的凋落物，凋落物数量和质量发生显著改变。与此同时长白山苔原氮沉降量也在逐年增加，导致了土壤中氮的累积，势必影响凋落物的分解。凋落物作为连接植物和土壤的纽带，其分解过程中碳（C）、氮（N）、磷（P）等化学组分和化学计量比的变化直接和间接影响着土壤养分有效性和植物养分利用策略。为揭示氮沉降增加对长白山苔原带不同类型凋落物化学组分及生态化学计量特征早期变化的影响，开展了为期8个月的模拟氮沉降室内凋落物分解实验。在苔原带采集灌木优势种牛皮杜鹃和草本优势种小叶章的凋落物带回实验室，模拟灌木牛皮杜鹃群落、灌草混合的牛皮杜鹃-小叶章群落和草本小叶章群落的3种不同类型凋落物，设置三个施氮处理：对照（CK，0 g N m-2 a-1）、低氮（LN，10 g N m-2 a-1）、高氮（HN，20 g N m-2 a-1）。研究表明：（1）不施氮处理时，3种凋落物的C、P均呈释放状态，木质素（Li）呈先累积再略有降解趋势；牛皮杜鹃凋落物的N元素富集而其余两种凋落物N元素呈释放状态；灌草混合和草本凋落物比原生的灌木凋落物C和N元素释放快、Li累积少；而灌木凋落物的P释放略快于灌草和草本凋落物。3种植被类型凋落物的C/N、C/P、Li/N大小表现为：牛皮杜鹃凋落物>牛皮杜鹃-小叶章混生群落凋落物>小叶章凋落物；N/P表现为：小叶章凋落物>牛皮杜鹃凋落物>牛皮杜鹃-小叶章混生群落凋落物。（2）氮沉降促进3种类型凋落物分解过程中C、N和P化学组分的释放，且氮浓度越高促进作用越显著。在牛皮杜鹃凋落物分解过程中，氮素添加到达某一阈值后，其C/N、C/P、N/P、Li/N的降幅最大，后续若再增加氮素，其对化学计量比的影响均会减弱；本实验中的氮素添加量增加促进了小叶章凋落物的C/N、Li/N下降。（3）草本植物入侵引起凋落物类型的变化带来凋落物分解加快，将导致长白山苔原带养分循环的变化；氮沉降增加对小叶章凋落物化学组分的释放及C/N、Li/N的下降更为促进，小叶章凋落物内难分解化合物减少，分解受到促进。高氮沉降加快了小叶章凋落物与土壤、草本植物之间的养分循环。因此，随着未来苔原带氮沉降量的增加，将更有利于小叶章在与牛皮杜鹃的竞争中获胜，使苔原带呈现草甸化趋势。 Abstract:The Changbai Mountain tundra is the only typical alpine tundra of eastern China and eastern Eurasia. In the recent 30 years, herbaceous plants have invaded from low altitude to the alpine tundra, which transformed shrub tundra to shrub-herb-mixed tundra and herb tundra, causing significant changes to the litter components. To understand the response of chemical composition and ecological stoichiometric characteristics of three types of litter to simulated nitrogen deposition in the Changbai Mountain tundra, an artificial simulated litter decomposition experiment was designed and conducted. Rhododendron aureum (native dominant shrub species) litter, Deyeuxia angustifolia (invasion herb species) litter and Rhododendron aureum-Deyeuxia angustifolia-mixed litter collected from the Changbai alpine tundra were used to set up nitrogen addition experiment at three levels under laboratory condition:control group (CK:without nitrogen addition), low N level group (LN:10 g N m-2 a-1)), and high N level group (HN:20 g N m-2 a-1)). Then we collected litter after decomposition and measured the content of C, N, P and lignin (Li), aiming to study the differences of chemical composition and ecological stoichiometric characteristics of the litter with different components and nitrogen addition levels. The results showed that:(1) Without nitrogen addition, the content of C and P in the litter reduced significantly while the content of Li increased at the beginning and then reduced; the content of N in the R. aureum litter increased significantly while the content of N in the R. aureum litter and the mixed litter reduced. C/N, C/P, Li/N of the litter of three types decreased by R. aureum>R. aureum-D. angustifolia-mixed>D. angustifolia; N/P of the litter of three types decreased by D. angustifolia>R. aureum> R. aureum-D. angustifolia-mixed. (2) The simulated nitrogen deposition promoted the release of nutrients during decomposition process and the promoting effects of high nitrogen addition turned out to be more significant. C/N, C/P, N/P, Li/N of the R. aureum litter decreased rapidly at a certain nitrogen addition threshold then the effects on ecological stoichiometric characteristics would be weakened if more nitrogen was added. In our study, high nitrogen addition promoted the decline of C/N and Li/N of the D. angustifolia litter. (3) Change of litter components caused by herbaceous species invasion would promote the decomposition of litter and affect the nutrient cycle mechanisms of Changbai Mountain alpine tundra. As nitrogen deposition increased, the contents of C, N, P, Li and C/N, Li/N of the D. angustifolia litter decreased further and refractory compounds decreased. Nitrogen deposition accelerated nutrients cycle between the D. angustifolia litter, soils and herbaceous plants. Thus, we suggest that the increase of nitrogen deposition will be more favorable to the win of D. angustifolia in the competition with R. aureum, which will impulse meadowization trend in the Changbai Mountain alpine tundra. 参考文献 相似文献 引证文献

The alpine tundra on Changbai Mountain was formed as a left-over ‘island’ in higher elevations after the glacier retrieved from the mid-latitude of Northern Hemisphere to the Arctic during the fourth ice age. The alpine tundra on Changbai Mountain also represents the best-reserved tundra ecosystems and the highest biodiversity in northeast Eurasia. This paper examines the quantity of carbon assimilation, litters, respiration rate of soil, and storage of organic carbon within the alpine tundra ecosystems on Changbai Mountain. The annual net storage of organic carbon was 2092 t/a, the total storage of organic carbon was 33457 t, the annual net storage of organic carbon in soil was 1054 t/a, the total organic carbon storage was 316203 t, and the annual respiration rate of soil was 92.9% and was 0.52 times more than that of the Arctic. The tundra-soil ecosystems in alpine Changbai Mountain had 456081 t of carbon storage, of which, organic carbon accounted for 76.7% whereas the mineral carbon accounted for 23.3%.

A study was conducted to test the correlation between biomass and elevation and the differences in concentration and storks of nutrients among five vegetation types (Felsenmeer alpine tundra vegetation-FA, Lithic alpine tundra vegetation-LA, Typical alpine tundra vegetation-TA, Meadow alpine tundra vegetation-MA, and Swamp alpine tundra vegetation-SA) on alpine tundra of Changbai Mountains, Jilin Province, China in growing seasons of 2003, 2004 and 2005. The biomass of 43 mono-species and soil nutrients in alpine tundra ecosystem were also investigated. Dominant species from Ericaceae (such as Rhododendron chrysanthum and Vaccinium jliginosum var. alpinum) were taken to analyze organ biomass distribution. Result showed that the biomass and elevation had a significant correlation (Biomass=−237.3 ln(Elevation) +494.36; R2=0.8092; P<0.05). No significant differences were found in phosphorus and sulphur concentrations of roots, stems and leaves among the five vegetation types. There were significant differences in nitrogen and phosphorus stocks of roots, stems and leaves and in sulphur stock of stems and leaves among TA, MA, and SA vegetation types (p<0.05). The nutrient stock of five vegetations was averagely 72.46 kg·hm−2, of which N, P, S were 48.55, 10.33 and 13.61 kg·hm−2, respectively. Soil N and S concentrations in meadow alpine tundra soil type was significantly higher than those in other four soil types (Cold desert alpine tundra soil, Lithic alpine tundra soil, Peat alpine tundra soil, and Gray alpine tundra soil). Phosphorous concentration in SA type was higher (p<0.05) than in other types. Soil nutrient stock (0–20cm) was averagely 39.59 t·hm−2, of which N, P, S were 23.74, 5.86, 9.99 t·hm−2, respectively.

Climate and environmental changes have caused changes in alpine tundra worldwide in recent decades. However, the roles of snow cover on tundra vegetation change remain less studied. There were obvious changes of alpine tundra vegetation, such as herbaceous encroachment and shrub expansion reported in Changbai Mountains in recent decades. This study investigates the relationship between snow cover and vegetation change (1988–2017) in alpine tundra of the Changbai Mountains by analysing the hydrological distribution of spring snowmelt in the tundra. We mapped the wet snow extent using Sentinel‐1 synthetic aperture radar (SAR) spaceborne data and estimated the snow water equivalent (SWE). We proposed a measure of relative water accumulation (RWA), which was determined by both rainfall and SWE, to represent water flowing through each pixel. We found strong correlations between RWA and vegetation change in different mountain aspects. Spring snowmelt leads to inter‐mountain aspect differences in hydrological distribution, with the western aspect showing a significant higher RWA than the eastern and northern aspects, which could attribute to the greater vegetation change in the western mountain aspect. Our results suggest that the distribution of snow in alpine tundra and the different mountain aspects hydrological conditions have important implications for the study of vegetation change in alpine tundra.

The effects of tourism disturbance on the community structure composition and variation of species diversity of Rhododendron chrysanthum population in the alpine tundra of Changbai Mountain were studied to provide reference for better protection of the ecological environment of Changbai Mountain. At different altitudes in the alpine tundra, the regions close to and far from the tourist routes were selected as the study sites, and the typical Rhododendron chrysanthum community in the alpine tundra was selected as the research object. The results showed that tourism disturbance would affect the plant growth of Rhododendron chrysanthum community. The average height, relative coverage and relative density of Rhododendron chrysanthum decreased, leading to the decrease of the important value and dominance of Rhododendron chrysanthum in the whole community. The higher the intensity of tourism disturbance was, the more significant the characteristics of Rhododendron chrysanthum were. In addition, the variation of the biodiversity of Rhododendron chrysanthum community under different tourist disturbance intensity in the middle and low altitude areas of Changbai Mountain alpine tundra was consistent with the theory of “moderate disturbance hypothesis”. At high altitude, Shannon-Wiener species diversity index, Pielou evenness index and Simpson dominance index of Rhododendron chrysanthum community all decreased with the decrease of disturbance intensity. Therefore, in order to achieve a better development of tourism in Changbai Mountain, some measures should be taken to reduce the impact of the disturbance intensity of tourism activities on the plant community in the scenic area.

Deyeuxia angustifolia (Komarov) Y. L Chang is an herb species originating from the birch forests in the Changbai Mountain. Recently, this species has been found encroaching into large areas in the western slopes of the alpine tundra in the Changbai Mountain, threatening the tundra ecosystem. In this study, we systematically assessed the response of the rhizosphere soil microbial to D. angustifolia encroaching in alpine tundra by conducting experiments for two vegetation types (shrubs and herbs) by real-time PCR and Illumina Miseq sequencing methods. The treatments consisted of D. angustifolia sites (DA), native sites (NS, NH) and encroaching sites (ES, EH). Our results show that (1) Rhizosphere soil properties of the alpine tundra were significantly impacted by D. angustifolia encroaching; microbial nutrient cycling and soil bacterial communities were shaped to be suitable for D. angustifolia growth; (2) The two vegetation community rhizosphere soils responded differently to D. angustifolia encroaching; (3) By encroaching into both vegetation communities, D. angustifolia could effectively replace the native species by establishing positive plant-soil feedback. The strong adaptation and assimilative capacity contributed to D. angustifolia encroaching in the alpine tundra. Our research indicates that D. angustifolia significantly impacts the rhizosphere soil microbial of the alpine tundra.

Alpine plant communities are highly sensitive to global warming. One of the consequences of the warming is encroachment by herbaceous plants from forests at low elevations into alpine ecosystems. In the Changbai Mountains, narrowleaf small reed (Deyeuxia angustifolia (Kom.) Y. L. Chang) from mountain birch forests encroached upward into alpine tundra, gradually replacing native tundra shrubs such as Rhododendron (Rhododendron aureum Georgi). How encroaching plants affect native plant communities is not fully understood. In this study, we analyzed above- and belowground biomass of alpine plant communities at five encroachment levels to investigate how biomass allocation changed at species and community scales. Our research showed that native plants are forced to change their morphology to cope with competition, at both above- and belowground levels, from encroaching plants. We found that (1) R. aureum increased the shoot height and leaf area in order to compete with D. angustifolia; (2) above- and belowground biomass of D. angustifolia increased while above- and belowground biomass of R. aureum decreased with increasing levels of encroachment; and (3) D. angustifolia encroachment reduced the total biomass of alpine tundra. Encroachment by herbaceous plants has a long-term negative impact on the ability of tundra plants to sequester carbon in the alpine tundra of the Changbai Mountains.

Deyeuxia angustifolia upward migration and nitrogen deposition change soil microbial community structure in an alpine tundra

Nutrients and biomass spatial patterns in alpine tundra ecosystem on Changbai Mountains, Northeast China

In recent years, herbaceous species such as Deyeuxia angustifolia (Kom.) Y. L. Chang has invaded alpine tundra regions of the western slope of the Changbai Mountains. Because atmospheric nitrogen deposition is predicted to increase under a warming climate and D. angustifolia is sensitive to nitrogen addition, field experiments were conducted from 2010 to 2013 to determine the effect of increased nitrogen deposition on the mechanisms of D. angustifolia invasion. The goal of this study is to evaluate the impact of increased nitrogen deposition on the changes in alpine tundra vegetation (consisting mostly of Rhododendron chrysanthum Pall. and Vaccinium uliginosum Linn.). The results showed that: 1) simulated nitrogen deposition affected overall characteristics and structure of R. chrysanthum and V. uliginosum communities and had a positive impact on the growth of tundra vegetation invaded by D. angustifolia; 2) R. chrysanthum was more resistant to invasion by D. angustifolia than V. uliginosum; 3) simulated nitrogen deposition could improve the growth and enhance the competitiveness of D. angustifolia, which was gradually replacing R. chrysanthum and V. uliginosum and might become the dominant species in the system in future, transforming alpine tundra into alpine meadow in the Changbai Mountains.

Light utilization efficiency ( LUE ) directly influences the distribution of energy and rate of photosynthesis in all layers of vegetation. LUE is very valuable in deciding the integrated limits of environment to photosynthesis and plant growth allocation of aboveground, and is an important index in weighing functions of system. In China, the studies on LUE focus usually on crops, rarely on natural vegetations, and mostly calculate mean LUE over the country. The studies on LUE of natural vegetations in some regions are limited to one or two types of vegetation. Thus, it is very difficult to reflect the total conditions of all vegetations over these regions in different periods. In the study, leaf area index ( LAI ) that greatly influences LUE of vegetation was received from remote sensing images. The ecosystem productivity process model at landscape scale (EPPML) that described carbon cycle and water cycle of system was built by computer program (Visual C++), and seasonal dynamics and spatial distributions of total solar radiation, net primary productivity ( NPP ) and LUE in Changbai Mountain Nature Reserve were simulated. Geographical Information System (GIS) was used to process, analyze and display spatial data. Thus, we could extend and convert the studies on physiological ecology of plants from small scale to a larger scale. EPPML uses the principles of Century, BIOM_BGC, Forest_BGC and BEPS for quantifying the biophysical processes governing ecosystem productivity, but the original model is modified to better represent Changbai Mountain region. A numerical scheme is developed to integrate different data types: remote sensing data (TM), gridded vegetation, soil and topographic maps at 30_m resolution in Albers projection; daily meteorological data in Changbai Mountain station in 1995, including precipitation, maximal temperature, minimal temperature, mean temperature, solar zenith angle at noon, air pressure and wind speed; diameter data from field measurement and national forest survey; data from literatures for inputs to EPPML and validation of EPPML. Vegetation index is derived from remote sensing data for estimating daily LAI and biomass at landscape scale. The information about vegetation type, soil type, elevation, slope and aspect can be derived from vegetation, soil and topographic maps. EPPML uses the biochemical model for photosynthesis of leaves developed by Farquhar et al. (1980) to simulate the rate of photosynthesis. NPP is the organic matter eliminating respiration from gross photosynthetic productivity ( GPP ). In addition, EPPML uses the sub_module MT_Clim in Forest_BGC to calculate total solar radiation. In EPPML, the spatial scale is 30 m and temporal scale is daily and yearly. The whole simulating process is easily understood and realized. EPPML is run and values are cumulated in each pixel. The major outputs include seasonal dynamics and spatial distributions of some carbon cycle and water cycle variables including NPP and LUE . The results indicated that the seasonal variation of LUE of vegetations in Changbai Mountain was similar to that of NPP with peak value in July (2.9%). The LUE in spring, summer, autumn and winter averaged 0.551%, 2.680%, 0.551% and 0.047% respectively. The annual LUE of all vegetation types averaged 1.075%, varying from -3.272% to 3.556%. The maximal annual LUE appeared in mixed broad_leaved and korean pine forests (1.653%), minimum in alpine grasses (0.146%), others being Changbai larch forest (1.227%), spruce_fir forest (1.019%), meadow (0.983%), broad_leaved forest (0.728%), shrub (0.478%), alpine tundra (0.442%) and Betula ermanii forest (0.298%). Though the LUE of mixed broad_leaved and korean pine forests were very high, it still had great increasing potential. In conclusion, EPPML could well and truly simulate NPP and total solar radiation of main vegetations at landscape scale in Changbai Mountain Nature Reserve. Therefore, it could well reflect the seasonal dynamic a

Composition and Spatial Distribution of Soil Mesofauna Along an Elevation Gradient on the North Slope of the Changbai Mountains, China

The vegetation of alpine tundra in the Changbai Mountains has experienced great changes in recent decades. Narrowleaf small reed (Deyeuxia angustifolia), a perennial herb from the birch forest zone had crossed the tree line and invaded into the alpine tundra zone. To reveal the driven mechanism of D. angustifolia invasion, there is an urgent need to figure out the effective seed distribution pattern, which could tell us where the potential risk regions are and help us to interpret the invasion process. In this study, we focus on the locations of the seeds in the soil layer and mean to characterize the effective seed distribution pattern of D. angustifolia. The relationship between the environmental variables and the effective seed distribution pattern was also assessed by redundancy analysis. Results showed that seeds of D. angustifolia spread in the alpine tundra with a considerable number (mean value of 322 per m2). They were mainly distributed in the low elevation areas with no significant differences in different slope positions. Effective seed number (ESN) occurrences of D. angustifolia were different in various plant communities. Plant communities with lower canopy cover tended to have more seeds of D. angustifolia. Our research indicated reliable quantitative information on the extent to which habitats are susceptible to invasion.

长白山西坡岳桦林带的草本植物(以小叶章为代表)侵入了苔原带,形成了独特的植物入侵现象。在光谱及影像分析的基础上,结合GPS(Global Positional System)定位技术,并依据小叶章与牛皮杜鹃的光谱差异及其反演的NDVI (Normalized Difference Vegetation Index)植被指数,揭示小叶章侵入苔原带的过程;通过对不同侵入时间、强度的斑块进行群落调查及土壤测试,探究小叶章侵入苔原带的生态后果。结果显示小叶章侵入苔原带始于20世纪80年代后期,由低海拔向高海拔推进,进入21世纪后逐渐形成了稳定的以小叶章为优势物种的植物群落结构。目前,低海拔处的小叶章斑块经过多年扩张已连接成片,而高海拔处的斑块正处于扩张的初期阶段。从生物多样性变化可以看出,小叶章侵入苔原带导致植物群落多样性升高和物种数量的增加,苔原带原有的灌木数量明显减少,草本植物逐渐增多。植被的改变影响了土壤的理化性质,C/N比下降,土壤腐殖质含量和全氮含量下降,但速效氮和土壤持水能力上升,土壤养分的高效利用又进一步推动了小叶章的侵入。小叶章侵入苔原带已经造成了严重的生态后果。;In China, the alpine tundra of Changbai Mountain is one of only three areas in China with this type of rare alpine tundra. The vegetation has undergone significant change in recent decades. Herbaceous species from the ‘<em>Betula ermanii</em> zone’, represented by <em>Deyeuxia angustifolia</em>, have invaded the alpine tundra zone on Changbai Mountain. This incursion represents a unique phenomenon in the mountainous areas of China. We examined the incursion process of <em>D. angustifolia</em> using GPS (Global positional system) techniques based on spectral and image analysis. In the study area, GPS equipment was used to identify individual <em>D. angustifolia</em> patches. Spectral analysis, particularly the red edge bands, was conducted by comparing the hyperspectral data between the invasive D.<em> andustifolia</em> and the native species, <em>Rhododendron chrysanthum</em>. The spectral diversity of the invasive and native species' enabled us to compare their NDVI (Normalized Difference Vegetation Index), which was used to analyze within patch changes in vegetation. Landsat TM images from 1983, 1999, 2002, 2006 and 2008 were used to calculate the NDVI index. The results showed that the incursion of <em>D. angustifolia</em> began in the 1980s. Currently, <em>D. angustifolia</em>has successfully invaded this alpine landscape with the gradual trend following an altitudinal gradient. The incursion range has extended from relatively low elevations to higher elevations. Moreover, the inference is that <em>D. angustifolia</em> patches at lower elevations are interconnected forming relatively large patches. At higher elevations in the tundra landscape, these <em>D. angustifolia</em> patches were smaller and more scattered.We also investigated the ecological consequences of the <em>D. angustifolia</em> invasion using plant community surveys and soil tests. The <em>D. angustifolia</em> patches were defined as patches at different times of invasion, which consisted of three different invasive levels (low, medium and high levels of invasion). In the newly formed plant community <em>D. angustifolia</em> was the dominant species. While this invasion altered the native plant community structure and enhanced biodiversity, it altered some soil properties including both physical and chemical properties. Compared with the native plant community, dominated by <em>R. chrysanthum</em>, the invasive patches showed higher Shannon-Wiener diversity and species richness. Changes in abundance and evenness of the community suggested that <em>D. angustifolia</em> would occupy the most dominate position in that community. The change of community structure resulted in the reduction of shrubs and increased the number of herbaceous species. The change of vegetation directly or indirectly led to changes in soil properties. The progression of invasion resulted in a decrease in the carbon/nitrogen ratio, soil humus and total nitrogen. However, the available nitrogen and soil water content increased. The changes in soil nutrients were closely related to changes in physical soil properties, especially for soil water content. The increases in soil water content altered nitrogen fixation processes, microbial decomposition and nitrification. We propose that the efficient use of soil nutrients may promote further <em>D. angustifolia</em> invasion. Moreover, we suggest that a time lag occurs between changes in the vegetation and soil properties.The invasion of <em>D. angustifolia</em> on the alpine tundra ecosystem has and continues to have severe impacts.