Species Composition Of Plant Communities Research Articles

Species composition of semi‐natural mesic grasslands as a factor influencing the methane yield of plant biomass (Central Europe)

AbstractSemi‐natural lowland and mountain mesic meadows are grasslands rich in species, and their conservation status depends on treatments such as mowing or grazing livestock. In many countries, the condition of grasslands is deteriorating because of their inappropriate use or abandonment. This study aimed to determine the effects of the species composition of plant communities and functional plant groups on the methane yield from biomass harvested from mesic grasslands in the Sudetes Mountains. Biogas potential analysis was performed based on biomass samples collected from Poland and the Czech Republic. The biogas potential was determined in 40 day‐long batch anaerobic digestion tests. The average methane yield obtained from the biomass was 246 ± 16 NL CH4 kg−1 VS, whereas the methane yield per hectare was 870 ± 203 m3 CH4 ha−1. Plant communities comprising different dominant species had no effect on the methane yield but affected the methane yield per hectare. Additionally, the species composition of grasslands with a higher percentage of forbs had lower biomass yield, resulting in lower methane yields per hectare. The continuity of the low‐intensity management of mountain grassland, which can be provided by the utilization of their biomass for bioenergy production, sustains high biodiversity and ensures appropriate meadow conservation.

Drought, nitrogen deposition and arthropod herbivory modify plant establishment dynamics after soil disturbance

Global change projections predict more recurrent and intense drought coupled with more frequent soil disturbance events and increased levels of N deposition related to intensive land-use. How these abiotic drivers interact with each other and with biotic drivers in determining plant community dynamics is still unclear.Our study aimed to disentangle the roles of biotic and abiotic drivers in plant natural succession after soil disturbance. We carried out a factorial field experiment in which we performed soil disturbance in two seasons and manipulated drought, N deposition and herbivory. After each disturbance event, we monitored plant establishment dynamics.The species composition of plant communities established after disturbance was different in the early and late season trial probably due to different phenology of species from the seed bank. Depending on the timing of disturbance, plant communities responded differently to drought and N. In particular, seedling emergence and growth appeared sensitive to water stress only in the late season trial. Irrespective of the other treatments, arthropod herbivores increased the number of plant species established after soil disturbance. N generally had a negligible effect on plant community dynamics. We only observed positive effects of N on plant biomass in in the late season trial when there was a high water availability.Under future global change, we expect drought to affect plant establishment after soil disturbance by interacting with biotic and abiotic drivers. In particular, we showed that overlooked drivers such as timing of soil disturbance and arthropod herbivory will play an important role in shaping novel plant communities. Our results stress the critical need to adopt a multiple factor approach when assessing global change impacts on plant community diversity, composition and recovery ability.

Topography and soil content contribute to plant community composition and structure in subtropical evergreen-deciduous broadleaved mixed forests

Topography and soil factors are known to play crucial roles in the species composition of plant communities in subtropical evergreen-deciduous broadleaved mixed forests. In this study, we used a systematic quantitative approach to classify plant community types in the subtropical forests of Hubei Province (central China), and then quantified the relative contribution of drivers responsible for variation in species composition and diversity. We classified the subtropical forests in the study area into 12 community types. Of these, species diversity indices of three communities were significantly higher than those of others. In each community type, species richness, abundance, basal area and importance values of evergreen and deciduous species were different. In most community types, deciduous species richness was higher than that of evergreen species. Linear regression analysis showed that the dominant factors that affect species composition in each community type are elevation, slope, aspect, soil nitrogen content, and soil phosphorus content. Furthermore, structural equation modeling analysis showed that the majority of variance in species composition of plant communities can be explained by elevation, aspect, soil water content, litterfall, total nitrogen, and total phosphorus. Thus, the major factors that affect evergreen and deciduous species distribution across the 12 community types in subtropical evergreen-deciduous broadleaved mixed forests include elevation, slope and aspect, soil total nitrogen content, soil total phosphorus content, soil available nitrogen content and soil available phosphorus content.

Effects Exercised by Artificial Forest Stands on the Restoration of Secondary Virgin Lands in Agroforest Landscapes of Dry Steppes

For the first time, mathematical methods are used to assess the restoration of secondary virgin lands on dry-steppe fallow lands under the influence of artificial protective forest stands, a mandatory component of modern agroforest landscapes. Using variance analysis, Spearman’s rank correlation coefficient, and the method of correlation pleiades, it is established that artificial stands significantly affect the species composition of plant communities. The greatest impact of cluster forest stands on the species composition of plant communities is observed in their immediate vicinity. The study objects located far from the forest stands feature the maximum similarity coefficients with the virgin lands. It is shown that fallow lands in edge zones of artificial stands planted in a linear fashion are similar to phytocoenoses of adjacent areas by their species composition.

Vaccinium myrtillus L. в Кировской области (южно-таежная подзона): фитоценотическая приуроченность, экологические предпочтения

Vaccinium myrtillus L. is an important component for forming phyto-environment in boreal forest ecosystems, in which it develops various consortium connections. Being a mycorrhizal species, V. myrtillus improves nutrition and stimulates the growth of plants of all layers, supporting inter- and intra-specific connections of different layers of forest communities. In order to estimate the environment-forming role of V. myrtillus in ecosystems it is essential to acquire data on quantitative presence of the species in plant communities composition and on ecological-phytocoenotic peculiarities within its range. The aim of the study is to define phytocoenotic parameters and ecological conditions of V. myrtillus habitats within the southern taiga part of its range (Kirov region). We collected the material during the growing seasons of 2009-2015 and made 110 geobotanical descriptions according to common geobotanical methods (Methods of studies…, 2002). Ecological conditions were estimated based on species compositions in communities using 10 ecological scales by Dmitry Tsyganov (1983). The ecological discomfort index was determined for each habitat (Klimenko, 2012). Common methods of soil analyses were used for different biotopes of the studied species (Arinushkina, 1962). Hemeroby was determined by the species composition in plant communities, in which every species has individual human impact tolerance spectre (Frank and Klotz, 1990). V. myrtillus acts as a dominant or codominant of the herbaceous-shrub synfolium of boreal coniferous and mixed forest communities with 30-70% cover. It is accompanied by the following species: Vaccinium vitis-idaea L., Rubus saxatilis L., Juncus filiformis L., Calamagrostis epigeios (L.) Roth., Thelypteris palustris Schot, Melampyrum sylvaticum L., and Majanthemum bifolium (L.) F. Schmidt. The species is found on gley and gleyic podzolic soils, mostly sabulous, rarely-sandy; and on peatygley and sod-podzolic soils (See Table 1). Bilberry is common on high acidity soils with pH varying from 2.54 to 4.93. The concentration of organic carbon in bilberry forest litter varies from 5.71 to 69.2% (See Fig. 1). V. myrtillus is a mesobiont species whose average ecologic valency coefficient reaches 55%. In the investigated coenopopulations, the species achieves 8.15 to 50.10% of its potential capabilities regarding the studied factors. V. myrtillus is a hemieurybiont by climatic factors (0.58 points). It achieves its maximum on ombroclimatic scale (44.5%). According to climatic scales, ecological conditions of the studied habitats occupy the central position of all possible. The generalized spectrum of soil scales shows the species as a mesobiont (It–0.45). This allows widening V. myrtillus soil humidity scale 1.27 point left and soil moisture variability scale 0.80 points right. On other scales, the environmental position of the studied coenopopulations are within the data given by Dmitry Tsyganov for the species (See Table 2 and Fig. 2). The discomfort index is also given to estimate habitat ecological conditions. Based on phytoindication data and according to the discomfort index, we defined that the most favorable conditions of edapho- and climatopes for V. myrtillus are formed in sphagnum phytocoenoses. The least favorable conditions were noted in bilberry pine and bilberrypleurocarpous moss pine-spruce forest types. The study of hemeroby showed that oligo-mesohemerob species (highly sensitive to anthropogenic factors) prevail in all V. myrtillus coenopopulations, i.e. 41%. A-hemerob, a-euhemerob and polyhemerob species were not noted in any of the studied CPs (See Table 3 and Fig. 3). This proves that the species is of low resistance to anthropogenic influence and can survive moderate intensity human impact. The studied plant communities with V. myrtillus are low-hemerobic.

Elevation filters seed traits and germination strategies in the eastern Tibetan Plateau

Seeds are the colonizing propagules for many plants and may therefore contribute to the filtering of species during the process of colonization and community assembly. Environmental filtering of seed traits may occur among species and influence community composition, or within species and influence the environmental breadth that a given species inhabits. To test for evidence of such filtering of seed traits, we measured morphological and germination traits of seeds of 408 angiosperm species collected across an elevational gradient in the eastern Tibetan Plateau grasslands. We tested for elevational filtering of traits at the species level, as well as within 22 of those species that occurred at different elevations, in order to test whether within‐species variation reflected among‐species patterns. Elevational patterning occurred in both seed morphology and seed germination. Seeds were smaller, more elongated and had a higher surface area:volume ratio and shorter germination times at higher elevation. Seed morphology was associated with germination such that more elongated and smaller seeds with a higher surface area:volume ratio germinated faster, leading to earlier germination in seeds from high elevation. Within species, elevational variation in seed traits was observed in several species, but species differed in how those traits were distributed across elevation. These results suggest that taxonomic differences in seed traits may contribute to elevational variation in the species composition of plant communities, but that seed traits may be variably selected by elevation within species.

Phylogenetic relatedness of woody angiosperm assemblages and its environmental determinants along a subtropical elevational gradient in China

The species composition of plant communities is determined by a number of factors, including current environmental conditions as well as biogeographical and evolutionary history. Despite evidence that plant diversity decreases and species relatedness increases along latitudinal and environmental gradients (e.g., low temperatures), it remains unclear whether these same patterns occur along elevational gradients, especially in the subtropical mountainous areas harboring rich biodiversity. In this study, we explored the pattern of phylogenetic relatedness of woody angiosperm assemblages and examined the effects of temperature variables on the phylogenetic relatedness among angiosperm woody plants using generalized linear model in subtropical forest communities along a broad elevational gradient in the Dulong Valley of Yunnan Province, China. Our results showed that woody angiosperm species in local forest plots tend to be more phylogenetically related at higher elevations and in areas with lower temperatures. Additionally, winter average temperature, rather than mean annual temperature, is a major predictor of the pattern of increasing phylogenetic relatedness with increasing elevation. This finding is consistent with the prediction of ‘Tropical Niche Conservatism’ hypothesis, which highlights the role of niche constraints in driving phylogenetic community assembly along an elevational gradient.

Rapid Changes in Plant Communities of Natural Parks due to Recreational Use

The dynamics of the state of forest communities in sites exposed to recreational effects of different intensities is assessed by testing two assumptions: (1) the taxonomic richness and diversity of communities are lower and the number of synanthropic species is higher in sites exposed to significant recreational effects; (2) the number and proportion of synanthropic species continue to increase with continued recreational use. The studies were carried out from 2012 to 2019 in four specially protected areas in the Middle Urals (Russia). Monitoring was carried out in two plots in each area: one of them was exposed to heavy recreational impacts and the other was a control one. It is revealed that the average number of species is the same in communities from the recreational plots and from the control ones; however, the number and proportion of synanthropic species is higher and that of indigenous ones is lower under intensive recreation conditions. The proportion of synanthropic species significantly increased in communities from highly visited and, most importantly, rarely visited plots over 7 years. Therefore, the transformation of the species composition of plant communities in recreational nature reserves has been established not only in plots with intensive recreational impacts but also in rarely visited plots. This is a new empirical fact that indicates the possibility of rapid synanthropization of forest vegetation in these recreationally used protected areas.

Climate-driven changes in the composition of New World plant communities

Climate change is altering the distributions of species, which in turn causes shifts in the composition of plant communities. Specifically, rising temperatures should cause increasing relative abundances of heat-loving or heat-tolerant species (that is, ‘thermophilization’) and changes in precipitation should cause altered abundances of water-demanding species. We analysed millions of records of thousands of species and found that the plant communities in most ecoregions in North, Central and South America have experienced thermophilization over the past four decades (1970–2011). Thermophilization was fastest in ecoregions with intermediate temperatures and was positively correlated with warming rates within many biomes. Changes in the relative abundances of water-demanding species were less consistent and were not correlated with changes in precipitation, meaning that the drought sensitivity of some ecoregions may be increasing despite decreasing rainfall and increasing probabilities of drought. Climate-driven changes in plant community composition will affect the function and stability of New World ecoregions. Climate change is driving changes in the species composition of plant communities. Analyses of the collection records of thousands of New World plant species reveal widespread increases in the relative abundances of heat-loving species but less consistent responses to changes in precipitation.

Wetland Plant Communities of the Eastern Himalayan Highlands in Northern Bhutan

The study was conducted to characterize previously unexplored wetland vegetation in lower montane areas of the Himalaya (1597–2538 m above sea level) of Jigme Dorji National Park, Gasa District, Northern Bhutan. A random quadrat sampling method was employed to assess percent plant cover and environmental data were collected following standard procedures. Cluster and indicator species analyses using plant cover data were used to define the species composition of plant communities. Differences in community composition along gradients of elevation, slope, soil pH, available phosphorus, and peat/soil depth were analyzed using Canonical Correspondence Analysis (CCA). The wetlands supported 120 vascular plant species from 84 genera and 51 families. Analyses identified four plant communities, I to IV, each named from the three most prominent species. The key indicator species of four plant communities, Acorus calamus, Carex diandra, Equisetum ramosissimum, and Carex capillacea, dominate shallow fresh marsh, seasonally flooded basin of flat, fresh water meadow, and poor fen, respectively. Elevation and soil phosphorus were the most important environmental variables in explaining the variation in wetland vegetation. The findings can be used to support the work of conservation agencies to identify and conserve these plant communities and their habitats in the Himalaya.

Diet, ecological role and potential ecosystem services of the fruit bat, Cynopterus brachyotis, in a tropical city

Urbanisation is happening at an unprecedented pace, affecting ecological interactions between frugivores and plants by altering the species composition of plant communities. Cynopterus brachyotis, a bat common in cities, is known to provide important ecosystem services, such as seed dispersal. Studying its diet offers insights into how ecological roles of bats in tropical landscapes could be affected by urbanisation. We documented the diet of C. brachyotis in Singapore, and tested the hypothesis that urbanisation decreases dietary breadth and proportion of native plants in its diet. We collected droppings of C. brachyotis at nine sites, and used morphological and molecular methods to identify plant species they contained. We evaluated whether species richness, proportion of native species and composition of plants in diet varied according to various urbanisation metrics. We recorded 33 plant species belonging to 25 genera and 21 families. Ten are native, 17 are exotic, and six are indeterminate. Twelve have never been reported in diets of C. brachyotis anywhere. Contrary to our hypotheses, urbanisation was not associated with reduced dietary breadth or declining reliance on native plants. Our results suggest urban C. brachyotis have a generalist approach to foraging and can readily exploit exotic plants as food. Because urbanisation does not affect dietary breadth or the proportion of native species they eat, these bats potentially continue to play important ecological roles by dispersing seeds of native plants even in the most urbanised sites, which is important in aiding succession in degraded landscapes. However, they may equally disperse exotic species they have exploited.

Change in Vegetation on Meliorated Solonetcic Soils of the Peri-Yergenian Plain over 10 Years (Republic of Kalmykia)

Observations of the course of natural restoration of vegetation were repeated at nine sites of the Arshan–Zelmensky Scientific Station with the same methodology after 10 years on similar dates in May. The land-reclamation works lasted 20 years and was stopped almost 50 years ago. Comparison of the data from field work in the two observation periods (2008 and 2018) showed that the changes made by land reclamation to the soil salt profiles are preserved. All of these soils belong to the same type of highly transformed soils—deeply saline agrozems. The arable (0–45 cm) and sub-arable (50–60 cm) horizons highlighted in the 2008 descriptions were preserved in the soil profile; however, in samples from 2018, the salt content increased in most plots in the subsurface horizon, in particular, the ion chlorine. These changes were not reflected in the vegetation; the formation of plant communities characteristic of the final stages of secondary succession, not for solonetzic but for light chestnut soils, continues. The total number of species recorded at geobotanical sites decreased from 70 to 62. Almost half (35 species) fell from the list of species of 2008, and, by 2018, 27 species had been added. This occurred mainly in groups of perennial and annual herbaceous plant species. The drying and loss of tree and shrub species continues (Populus album, Quercus robur, Ulmus pumila, Acer tatrica, Cotinus coggygria); and only the pear (Pyrus communis) and golden currants (Ribes aureum) showed renewal. Despite the decrease in the total number of recorded species, the species richness of communities at all geobotanical sites increased by 1.5–2.5 times. In 10 years, the characteristic species of zonal communities have spread widely: Artemisia lerchiana, Tanacetum achilleifolium, Poa bulbosa, Stipa lessingiana, Leymus ramosus, A. austriaca. This contributed to the alignment of the species composition of plant communities at all observation points and caused an increase in the similarity of the species composition between them to 56–77%, as compared with 37–57% in 2008. A similar change was also found in the aboveground phytomass: there was not only an increase (the average values in 2008 and 2018 were 734 and 849 kg/ha, respectively) but also some leveling of its values between the plots. In virgin solonetz, which shows the “background” processes, the highly saline, top 20 cm in 1950 was leached of salts by 2008 and remained nonsaline in 2018. In 2018, the aboveground phytomass here more than two times higher than that in 2008.

Концепция классификации растительности России как отражение современных задач фитоценологии

Концепция классификации растительности России как отражение современных задач фитоценологии

Biological remediation of roadside areas

During the construction of highways, significant damage is caused to the environment: the soil cover is degraded, vegetation cover and the natural landscape are destroyed. The issue of minimizing the negative impact of this direction on the environment was not given enough attention. Therefore, one of the main issues of environmental protection is the timely implementation of works on reclamation of disturbed lands. Land areas of temporary allotment for road construction that are subjected to mechanical impact after the stage of technical reclamation are subject to biological reclamation, which is aimed at landscaping the roadside area. To achieve these goals, we used the method of developing measures for the reclamation of disturbed land during the construction of the highway. Activities on biological remediation can be performed as a result of: the serial complexity of the species composition of plant communities, which has long co-exist with man-made recultivated territories; the launch of the rehabilitation process which can be carried out simultaneously in a multispecies complex of phytocenosis, suggesting further its sustainable functioning. As a result of biological reclamation measures, using crops that are resistant to pollutants and meliorants, it is possible to gradually reduce the content of pollutants in the soil due to natural self-cleaning processes as a result of removal of elements by plants and their leaching outside the root layer of the soil.

БИОТОПИЧЕСКИЕ ОСОБЕННОСТИ РАСПРОСТРАНЕНИЯ И УСТОЙЧИВОСТЬ К АНТРОПОГЕННОМУ ВОЗДЕЙСТВИЮ LISTERA OVATA (L.) R.BR. В КИРОВСКОЙ ОБЛАСТИ

Stash ovate (Listera ovata (L.) R. Br.) – herbaceous short-rooted perennial. The purpose of the study is to identify the environmental preferences of Listera ovata and its resistance to anthropogenic impact on the territory of the Kirov region. As a result of phytoindication of the studied Listera ovata habitats, ecological characteristics were obtained using six H. Ellenberg scales (1974). According to the illumination scale, which evaluates the ratio of plants to the relative illumination prevailing in the habitat of the species, Listera ovata grows at different levels of illumination: as in open habitats with 60–80 % illumination. In relation to the thermoclimatic factor that evaluates heat / cold resistance, the studied species is an inhabitant of a temperate climate (the 5th stage of the Ellenberg scale). On the continental scale Listera ovata is characterized as a suboceanic species (4th stage of the Ellenberg scale), which corresponds to the geographical distribution zone of the species within the Kirov region. In relation to soil moisture, the distribution of the species in habitats with soils ranging from medium-wet (5th stage of the Ellenberg scale) to wet (6th stage of the Ellenberg scale) was noted. On the scale of soil acidity, which determines the dependence of species on acid-base soil conditions, Listera ovata occupies habitats characterized from moderately acidic (5th stage of the Ellenberg scale) to weakly alkaline soils (7th stage of the Ellenberg scale). According to the nitrogen richness scale, which shows the total supply of nutrients (N, K, P, Mg) in the soil, the species is confined to habitats with moderately provided basic nutrients (5th stage of the Ellenberg scale). Analysis of hemerobicity by species composition in plant communities showed that the studied plant communities with Listera ovata are mainly represented by oligo and meso-hemerobic species: from 30.56 to 37.78 %. These are species of communities that are close to natural, that tolerate irregular weak influences, and species of semi-natural communities that are resistant to extensive influences (Vaccinium vitis-idaea, Fragaria vesca, Asarum europaeum, Pimpinella saxifraga, Melica nutans, Maianthemum bifolium, Vaccinium myrtillus). The share of species of natural communities that do not tolerate anthropogenic influence is 1.65 %. About 21 % are occupied by species far from natural communities that are resistant to intensive use (Melilotus albus, Pastinaca silvestris, Calamagrostis epigeios). Weed species of natural and anthropogenic communities that suffer regular severe disturbances account for 7.67 % (Trifolium repens, Galium odorata, Taraxacum officinale). The share of specialized weed species of intensive crops is 4.06 % (Chamaenerion angustifolium, Tussilago farfara, Cirsium arvense, Galium aparine, Anthriscus sylvestris). Types of completely disturbed ecosystems in the studied habitats were not identified. All studied phytocenoses with L. ovata are dominated by anthropophobic species: from 62 to 77 %. The percentage of anthropotolerant species is not high and varies from 23 to 38 %.

祁连山东段高寒植被群落特征及其与地形气候因子关系研究

PDF HTML阅读 XML下载 导出引用 引用提醒 祁连山东段高寒植被群落特征及其与地形气候因子关系研究 DOI: 10.5846/stxb201812192760 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发项目（2018YFC0507102-05）；国家自然科学基金项目（31560128）；中央引导地方科技发展专项（ydzx20176200004893）；甘肃省科技计划资助项目（18JR3RA0200） Characteristics of alpine vegetation community and its relationship to topographic climate factors in the eastern Qilian mountain Author: Affiliation: Fund Project: 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:地形气候因子与物种分布的关系影响着高寒植被群落的演替，同时对山地水源涵养林功能和结构的维持具有重要的意义。以祁连山东段水源涵养林为研究对象，基于野外植物群落物种组成及地形气候因子调查数据，运用数量分类与排序等方法，探究了高寒植物群落特征及其与地形气候因子的关系。结果表明：65个调查样方中出现181个植物种，隶属40科，124属。科的物种组成及占总物种数比例分别为菊科30个种，占16.57%；蔷薇科17个，占9.44%；禾本科13个种，占7.22%；豆科11个种，占6.11%。毛茛科10个种，占5.56%。单属种82个，占总属数的66.13%。群落层片由乔木层、灌木层和草本层组成，乔木8种，灌木25种，草本148种。乔木层优势种有青海云杉、祁连圆柏、红桦。灌木层优势种有金露梅、山生柳、匙叶小檗、高山绣线菊。草本层优势种有甘肃薹草、珠芽蓼、早熟禾、唐松草、甘青蒿。TWINSPAN将高寒植被群落划分为7个群丛类型：群丛I红桦-红花蔷薇-甘肃薹草B. albosinensis-Rosa moyesii-C.kansuensis，群丛II青海云杉-匙叶小檗-甘肃薹草P.crassifolia-B.vernae-C.kansuensis，群丛III祁连圆柏-高山绣线菊-珠芽蓼Sabina chinensis-Spiraea alpine-P.viviparum，群丛IV高山绣线菊+鬼箭锦鸡儿-珠芽蓼S.alpine+Caragana jubata-P.viviparum，群丛V沙棘+甘青蒿+鼠掌老鹳草Hippophae rhamnoides+A.tangutica+Geranium sibiricum，群丛VI沙棘+苦荬菜+苦荞麦H.rhamnoides+Ixeris polycephala+Fagopyrum tataricum，群丛VII沙棘-冰草+西北沼委陵菜H.rhamnoides-Agropyron cristatum+Comarum salesovianum。7个群丛在DCA排序图上聚集分布，反映了较好的环境梯度。CCA排序结果表明，海拔是祁连山高寒植被群落植物种分布的最重要环境因子，其次是降水、温度、坡向、坡度。 Abstract:The relationship between the topographic climate factors and species distribution influences the succession and development of alpine vegetation communities and also has great significance to maintaining the functions and structure of mountain water conservation forests. In this study, the water conservation forest at the eastern Qilian mountain was taken as the research object. Based on the investigation data of plant community species composition, the topographic and climatic factors, the characteristics of alpine plant community and its relationship with the topographic and climatic factors were explored by quantitative classification and ordination. The results showed that 181 plant species were recorded in 65 samples belonging to 40 families and 124 genera. The largest family was Compositae (30 species), Rosaceae (17 species), Gramineae (13 species), Leguminosae (11 species), and Ranunculaceae (10 species), which accounted for 16.57%, 9.44%, 7.22%, 6.11%, 5.56% of the total species, respectively. The structure of the community consisted of tree layer, shrub layer, and herb layer, with 8 species of trees, 25 species of shrubs, and 148 species of herbs. The dominant species of tree layer were Picea crassifolia, Sabina chinensis, and Betula albosinensis. Potentilla glabra, Salix oritrepha, Berberis vernae, and Spiraea alpine were the dominant species of shrub layer. The dominant species of herb layer were Carex kansuensis, Polygonum viviparum, Poa annua, Thalictrum aquilegiifolium var. sibiricum, and Artemisia tangutica. TWINSPAN divided alpine vegetation communities into 7 cluster types. Ass.I B. albosinensis-Rosa moyesii-C. kansuensis, Ass.II P. crassifolia-B. vernae-C. kansuensis, Ass. III Sabina chinensis-Spiraea alpine-P. viviparum, Ass.IV S. alpine+ Caragana jubata-P. viviparum, Ass.V Hippophae rhamnoides+A. tangutica+Geranium sibiricum, Ass.VI H. rhamnoides+Ixeris polycephala+Fagopyrum tataricum, and Ass.VII H. rhamnoides-Agropyron cristatum+Comarum salesovianum. Seven clusters were clustered and distributed on the DCA ordination graph, which reflected a good environmental gradient. The CCA ordination results showed that altitude was the most important environmental factor for plant species distribution of alpine vegetation community in Qilian mountains, followed by precipitation, temperature, slope direction, and slope. 参考文献 相似文献 引证文献

Impact of Removal of Copper Leaf (<i>Acalypha fruticosa</i> Forssk.) on Plant Species Diversity and Abundance at Chemeron, Baringo County, Kenya

Invasive plant species may significantly alter plant species community composition and structure thereby negatively impacting on ecosystem services. Their impacts on plant communities may be both direct and indirect. The direct effects may include a reduction in the abundance and diversity of palatable plant species that constitute important forage for livestock, wildlife, and medicines for the local communities. Declines in ecosystem resilience are of the notable indirect effects of invasive species. The aim of this study was to assess the impacts of a plant species, copper leaf (Acalypha fruticosa) on floral diversity and abundance at Chemeron, Baringo County in Kenya. The study was guided by three questions: What is the plant composition in terms of grasses, herbs, shrubs, and trees in the study area? Are there any variations in plant abundance between the two sites (sites with and without Acalypha fruticosa)? Are there variations in plant species diversity between the two study sites? Two sites (one with A. fruticosa and another two without this invasive species) were selected within the Chemeron Research Centre. Two belt transects measuring 100 m × 20 m on each site were laid parallel to each other. Plant samples were collected from five 1 m × 1 m quadrats that were laid at intervals of 20 m. The plant species or specimens were identified to the species level using available taxonomic keys. Various indices including Shannon-Wiener (H’), Evenness Index, Richness Index and Simpson’s Index of Diversity Index (SDI) were calculated. All the diversity, richness and evenness indices were considerably higher in the site without A. fruticosa compared to that where this invasive species was present. Higher H’ (3.14 to 3.21) and SDI (0.93 to 0.94) values were noted in sites without the invasive species compared to H’ (2.11 to 2.20) and SDI (0.77 to 0.85) in sites with A. fruticosa present. Out of the 47 plant species identified, 39 and 20 of them occurred in the site without and with A. fruticosa, respectively. Further, there were more grasses (Aristida keniensis, Cynodon dactylon, Brachiaria lucrantha, Eragrostis racemosa, and Enteropogon macrostachyus) in the site without A. fruticosa compared to that with the invasive plant. The plants were also more evenly distributed in the site without A. fruticosa compared to that where the invasive plant was present. We conclude that A. fruticosa has a significant effect on plant species abundance and diversity as well as distribution. Its removal created a favourable environment for the growth of a variety of grasses. We therefore recommend to the agro-pastoralists and rangeland managers that A. fruticosa be mechanically removed by uprooting from grazing lands so as to increase forage availability and quality in the rangelands of South-Baringo.

The recovery rates of secondary savannas in abandoned pastures are poorly explained by environmental and landscape factors

AbstractQuestionAssessing the natural regeneration potential of degraded savannas is a crucial step in restoration planning, since that assessment will define the need for and costs of active intervention. Predicting natural regeneration, however, depends on the mechanistic understanding of ecosystem resilience. Here, we searched for the factors modulating plant communities spontaneously regenerating in abandoned pastures.LocationTropical savanna (cerrado), Brazil.MethodsOver two years, we quantified changes in the structure, richness and species composition of plant communities in 29 secondary savannas resulting from pasture abandonment. We then investigated the influence of soil and landscape attributes, exotic grass cover and time since pasture abandonment on the recovery rate and species composition of these communities.ResultsThe wide variation among sites was not explained by time since abandonment or distance to the nearest remnant native vegetation. Soil attributes, exotic grasses and native vegetation cover around a pasture explained a small fraction of the variation in the recovery rate. We did not find an isolated factor or a robust set of factors explaining the variation in the recovery rate for all vegetation attributes. Species composition was slightly influenced by exotic grasses, soil penetration resistance, proportion of fine soil particles and time since abandonment. Colonization and resprouting by savanna specialists over the two‐year period were hindered by exotic grasses.ConclusionThe use of predictive models based on soil properties, exotic grasses, landscape attributes or time since abandonment is unfeasible for inferring the recovery rate of savanna structure and richness after pasture abandonment. Case‐by‐case monitoring is required to support decisions on restoration intervention. Other factors, which are almost impossible to obtain, such as land‐use practices and history and the taxonomic or functional composition of pre‐existing vegetation, can potentially influence the recovery rate. Exotic grasses must be controlled to favour colonization and resprouting by savanna specialists.

Effect of thermal activity on the differentiation of the vegetation of the “Ruda” postmining heap in Zabrze (Poland)

This paper presents the results of a study on the vegetation of the thermally active postmining heap “Ruda” in Zabrze (Poland). The aims of the study were: (i) to show the differentiation of the vegetation that has developed as a result of the thermal activity, and (ii) to determine the effect of thermal activity of the spoil heap on species richness and species diversity of the vegetation. Twelve plant communities were recorded on the heap. Thermal activity has a statistically significant impact on species richness (<em>Z</em> = 2.13, <em>p</em> = 0.03) and species diversity (<em>Z</em> = 2.29, <em>p</em> = 0.02). The species composition of plant communities reflects the habitat conditions, which are conditioned by thermal activity. As the distance from a zone with increased thermal activity increases, the degree of the spontaneous succession of vegetation and the complexity of the vegetation increase. Moreover, the share of annual species and kenophytes decreases in favor of perennial plants and apophytes. The number of plant communities (from four to eight), their species richness (number of species from 15 to 22) and species diversity (Shannon–Wiener diversity index from 1.81 to 2.19) also increase. A DCA analysis showed an increase in the shading, humidity and pH of the substrate, and the thickness of the dead organic matter within the gradient of the thermal activity.

Tree Species Diversity of Ikogosi Warm Spring and Arinta Waterfall Watersheds, Nigeria: Implication for Sustainable Ecotourism

An in-depth knowledge of the richness, diversity and species composition of plant community is vital for providing information for planning and sustainable utilization. This study assesses the diversity of tree species of Ikogosi warm spring and Arinta waterfall watersheds in Ekiti State, Nigeria. Direct observation and vegetation assessment were used for data collection in two hectares (ha) of land divided into four plots of 50 m by 50 m in each of the two study sites (Ikogosi warm spring and Arinta waterfall). Two plots were diagonally selected within each hectare. All living trees of basal diameter ≥10 cm were identified and classified into families. Shannon-Weiner diversity index, species evenness, relative density (RD), relative dominance (RD0) and importance value index (IVI) were used to assess and compare tree species diversity and abundance. Sorenson’s coefficient was used to compare sites for overlapping of similarity. The results revealed that seventy eight (78) species and 25 families were recorded in both watersheds with family Malvaceae having the highest species density (15). Malacantha alnifolia (5) and Voacanga africana (5) were the species most frequently encountered. Species diversity indices revealed vegetation with very high tree species diversity and abundance in the two study sites. Species evenness value revealed even distribution in Arinta waterfall than in Ikogosi warm spring. Diameter and height distribution of trees at the two watersheds indicates a forest structure that is immature and still expanding. Anthocleista vogelii, has the highest value of RD0 (15.63) and IVI (10.6) respectively. The study revealed that some species such as Anthonotha macrophylla, Aningeria robusta, Bridelia atroviridis, among others are threatened and endangered. Consequently, it was recommended that management strategies should be put in place to improve status of the watersheds while conservation efforts should be stepped up for species with rarity index value to prevent them from going into extinction.