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1.
Urbanová M Kopecký J Valášková V Ságová-Marečková M Elhottová D Kyselková M Moënne-Loccoz Y Baldrian P 《FEMS microbiology ecology》2011,78(1):59-69
Changes in the abundance of bacteria and fungi and in the composition of bacterial communities during primary succession were investigated in a brown coal mine deposit area near Sokolov, the Czech Republic, using phospholipid fatty acids analysis, microarray and 16S rRNA gene sequencing. The study considered a chronosequence of sites undergoing spontaneous succession: 6-, 12-, 21- and 45-year-old and a 21-year-old site revegetated with Alnus glutinosa. During succession, organic carbon and the total nitrogen content increased while the pH and the C/N ratio decreased. Microbial biomass and bacterial diversity increased until 21 years and decreased later; bacteria dominated over fungi in the initial and late phases of succession. Bacterial community composition of the 6-year-old site with no vegetation cover largely differed from the older sites, especially by a higher content of Gammaproteobacteria, Cyanobacteria and some Alphaproteobacteria. Bacteria belonging to the genera Acidithiobacillus, Thiobacillus and related taxa, the CO(2) and N(2) fixers, dominated the community at this site. In the later phases, bacterial community development seemed to reflect more the changes in soil nutrient content and pH than vegetation with a decrease of Actinobacteria and an increase of Acidobacteria. The site revegetated with A. glutinosa resembled the 45-year-old primary succession site and exhibited an even lower pH and C/N ratio, indicating that recultivation is able to accelerate soil development. 相似文献
2.
3.
Patterns of community development vary among studied glacier forelands around the world. However, there have been few studies
of primary succession on glacial forelands in temperate regions of North America. We described patterns in community composition,
vegetation cover, diversity, and vegetation heterogeneity during primary succession on the foreland of Coleman Glacier, in
Washington State, USA. Community composition changed rapidly with high turnover between age classes. Cover increased through
succession as expected. Species richness and diversity were highest in early succession at small scales and in late succession
at larger scales. At small scales, heterogeneity decreased in early succession but increased in mature sites. At larger scales,
heterogeneity reached its lowest point earlier in succession. These scale-dependent patterns in diversity and heterogeneity
differ from results of other studies of glacier forelands. We hypothesize that these patterns arise due to the development
of a dense canopy of the deciduous shrub Alnus viridis followed by a dense canopy of Abies amabilis, Tsuga heterophylla, and Pseudotsuga menziesii. 相似文献
4.
科尔沁沙地草地植被恢复演替进程中群落优势种群空间分布格局研究 总被引:23,自引:6,他引:17
通过对处于流动沙地、半固定沙地和固定沙地等不同恢复演替阶段的群落的取样调查 ,研究了科尔沁沙地草地植被恢复进程中群落优势种群的空间分布格局及其动态变化。运用扩散系数、聚集指数、平均拥挤度、聚块性指数、Green指数、聚集强度、Poisson分布和负二项分布的 χ2 拟合检验等 7项指标 ,对群落优势种群的分布格局的研究结果基本一致 ,大多数物种的空间分布呈显著的聚集分布。在演替进程中种群格局强度的变化和群落总体聚集程度的变化与种群动态和群落结构的空间异质性相对应 ,较高的聚集程度是种群分布斑块化和群落结构的空间异质性的反映 ,随着演替进展 ,优势种的种群数量扩展 ,但种群分布的聚集强度下降 ,群落结构的空间异质性降低。在 7种测定分布格局的指标中 ,聚块性指数、Green指数和聚集强度是无量纲的指标 ,其大小不受种群大小的影响 ,其变化可以较好地指示格局强度本身的变化 ,并与种群动态和群落结构变化相联系 相似文献
5.
庐山森林景观格局变化的长期动态模拟 总被引:1,自引:0,他引:1
在以植被格局为基础的森林景观动态分析中,可通过森林演替推断景观格局的动态变化以及相应的景观生态过程。运用空间直观景观模型LANDIS,以庐山风景区为案例地,模拟森林植被在未来300 a的自然演替动态,在此基础上选取斑块面积比、聚集度、分维数、多样性指数和均匀度指数等景观格局指数,分析森林景观格局随森林演替的动态变化。结果表明:(1)阔叶林树种的绝对优势地位保证其斑块面积比呈现持续增长的稳定趋势,森林植被将朝着地带性常绿阔叶林方向演替;(2)景观聚集度特征方面,阔叶林树种在前150 a缓慢增长,而后150 a保持相对稳定,杉木林一直保持平稳,毛竹林在整个模拟阶段一直在不断下降直至演替结束;(3)各优势树种植被斑块的分维数都保持在1-1.1之间,说明各景观斑块的边缘相对较规则且变化较小;(4)景观多样性指数呈现出先上升后缓慢下降的趋势,而均匀度指数则呈现出先下降后上升再缓慢下降的变化态势。景观格局指数的变化特征与植被向顶极群落演替的趋势相吻合,该模拟结果可运用到庐山森林景观的管理实践中。从长远来看,应该继续实行严格的封山育林政策。 相似文献
6.
Simoneta Negrete Yankelevich Carlos Fragoso Adrian C. Newton Graham Russell O. William Heal 《Plant and Soil》2006,286(1-2):123-139
We test the hypothesis that secondary succession in Tropical Montane Cloud Forest (TMCF) in Mexico is accompanied by an increase in the spatial structuring of litter resources, soil nutrient concentrations and the soil macroinvertebrate community at a within-plot scale (5–25 m). This increased spatial structuring is expected because secondary succession in these forests is associated with an increase in the diversity of trees that dominate the canopy. If each tree species generates a particular soil environment under its canopy, then under a diverse tree community, soil properties will be spatially very heterogeneous. Tree censuses and grid sampling were performed in four successional stages of a secondary chronosequence of TMCF. Variography was used to analyse spatial patterns in continuous variables such as nutrient concentrations, while Spatial Analysis by Distance Indices (SADIE) was applied to determine patchiness in the distribution of soil macroinvertebrate taxa. Secondary succession was found to be accompanied by the predicted increase in the spatial structuring of litter resources and the macroinvertebrate community at the within-plot scale. Spatial patterns in the macroinvertebrate community only became evident for all taxa in the oldest forest (100 years old). Patches with low Ca and Mg concentrations in early successional soils were associated with patches where pine litter was most abundant while those with low P concentrations in late successional stages were associated with patches where oak litter was most abundant. Results suggest that anthropogenic disturbance aboveground promotes a more homogeneous resource environment in the surface soil, which compared to older forests, sustains a less diverse and less spatially structured macroinvertebrate community. 相似文献
7.
五大连池新期火山熔岩台地不同植被类型土壤微生物群落的功能多样性 总被引:2,自引:0,他引:2
土壤微生物群落是陆地生态系统的重要生物活性成分,其结构和功能多样性直接影响到系统的碳、氮等生态过程,微生物群落功能多样性与地上植被类型变化密切相关,开展植被类型对土壤微生物群落功能多样性的影响研究具有重要意义。以五大连池新期火山熔岩台地苔藓、草本、灌丛、矮曲林、针阔混交林5种典型植被类型为对象,利用BIOLOG微孔板法研究不同演替阶段植被类型土壤微生物群落功能多样性特征。结果表明:不同植被类型土壤微生物群落功能多样性存在显著差异。平均颜色变化率(AWCD)随培养时间延长而逐渐增加,大小顺序为:苔藓 > 针阔混交林 > 矮曲林 > 草本 > 灌丛。灌丛土壤微生物多样性指数与其他植被类型间差异显著。主成分分析结果表明,主成分1和主成分2分别能解释变量方差的56.24%和29.59%,不同植被类型下土壤微生物的碳源利用格局差异主要是由氨基酸类和带磷基糖类引起,二者合计解释总变异量的47.51%。冗余分析表明,速效磷、铵态氮、C:N和pH对微生物功能多样性具有显著的影响,羧酸类、氨基酸类、酯类和胺类的降解更易受到环境因素的影响。研究结果为进一步探讨植被类型与土壤微生物之间在植被演替过程中的关系提供参考。 相似文献
8.
SARAH E. DONOVAN GEORGIANNE J. K. GRIFFITHS RAHMAN HOMATHEVI LINTON WINDER 《Ecological Entomology》2007,32(1):1-10
Abstract. 1. Primary and logged lowland dipterocarp forest sites were sampled for subterranean termites using soil pits located on a grid system in order to detect any patchiness in their distribution.
2. A spatial pattern in termite distributions was observed in the primary and logged sites, but the response differed between soil-feeding and non-soil-feeding termites.
3. Spatial analysis showed that soil-feeding termites were homogeneously distributed in the primary forest but significantly aggregated in the logged forest. This pattern was reversed for non-soil-feeding termites and may result from differences in resource provisioning between the two sites.
4. Gaps in termite distribution comprised a greater area than patches for both feeding groups and sites, but gaps dominated the logged site.
5. A significant association between soil-feeding and non-soil-feeding termite distributions occurred at both sites. This arose from an association between patches in the primary forest and between gaps in the logged forest.
6. Termite spatial pattern was optimally observed at a minimum extent of 64 m and lag of 2 m.
7. The spatially explicit SADIE (Spatial Analysis by Distances IndicEs) analyses were more successful than (non-spatially explicit) multivariate analysis (Canonical Correspondence Analysis) at detecting associations between termite spatial distributions and that of other biotic and abiotic variables. 相似文献
2. A spatial pattern in termite distributions was observed in the primary and logged sites, but the response differed between soil-feeding and non-soil-feeding termites.
3. Spatial analysis showed that soil-feeding termites were homogeneously distributed in the primary forest but significantly aggregated in the logged forest. This pattern was reversed for non-soil-feeding termites and may result from differences in resource provisioning between the two sites.
4. Gaps in termite distribution comprised a greater area than patches for both feeding groups and sites, but gaps dominated the logged site.
5. A significant association between soil-feeding and non-soil-feeding termite distributions occurred at both sites. This arose from an association between patches in the primary forest and between gaps in the logged forest.
6. Termite spatial pattern was optimally observed at a minimum extent of 64 m and lag of 2 m.
7. The spatially explicit SADIE (Spatial Analysis by Distances IndicEs) analyses were more successful than (non-spatially explicit) multivariate analysis (Canonical Correspondence Analysis) at detecting associations between termite spatial distributions and that of other biotic and abiotic variables. 相似文献
9.
Changes in the root-associated fungal communities along a primary succession gradient analysed by 454 pyrosequencing 总被引:2,自引:0,他引:2
Blaalid R Carlsen T Kumar S Halvorsen R Ugland KI Fontana G Kauserud H 《Molecular ecology》2012,21(8):1897-1908
We investigated changes in the root-associated fungal communities associated with the ectomycorrhizal herb Bistorta vivipara along a primary succession gradient using 454 amplicon sequencing. Our main objective was to assess the degree of variation in fungal richness and community composition as vegetation cover increases along the chronosequence. Sixty root systems of B. vivipara were sampled in vegetation zones delimited by dated moraines in front of a retreating glacier in Norway. We extracted DNA from rinsed root systems, amplified the ITS1 region using fungal-specific primers and analysed the amplicons using 454 sequencing. Between 437 and 5063 sequences were obtained from each root system. Clustering analyses using a 98.5% sequence similarity cut-off yielded a total of 470 operational taxonomic units (OTUs), excluding singletons. Between eight and 41 fungal OTUs were detected within each root system. Already in the first stage of succession, a high fungal diversity was present in the B. vivipara root systems. Total number of OTUs increased significantly along the gradient towards climax vegetation, but the average number of OTUs per root system stayed unchanged. There was a high patchiness in distribution of fungal OTUs across root systems, indicating that stochastic processes to a large extent structure the fungal communities. However, time since deglaciation had impact on the fungal community structure, as a systematic shift in the community composition was observed along the chronosequence. Ectomycorrhizal basidiomycetes were the dominant fungi in the roots of B. vivipara, when it comes to both number of OTUs and number of sequences. 相似文献
10.
Questions: The early phases of primary succession are governed by chance events and dispersal‐related processes in an environment that is largely free of competition. Thus, the predictability of vegetation patterns using environmental site factors can be expected to be low and spatial autocorrelation to be high. We asked whether the match between vegetation and environment becomes better in the course of succession, and whether vegetation types shift their realized niche with time. Location: Lignite mining region in Central Germany, the post‐mining landscape “Goitzsche” (Saxony‐Anhalt). Methods: Vegetation types were mapped in a 10‐m grid (total area 4.8 ha), starting in 1995, at 3‐year intervals until 2007. We used a temporal comparison of habitat models. We applied: GLS regression to partition the variation in coverage of vegetation types into environmental (soil pH) and spatial components; logistic regression to model the presence/absence of vegetation types along a soil acidity gradient; and autologistic regression allowing for soil acidity and neighbourhood effects. Results: For most vegetation types, the proportion of variation explained by space was high but declined during succession. The outcome of autologistic models suggests that soil acidity often plays a minor role compared to neighbourhood effects in the earlier phase of succession than 12 years later. For four vegetation types, the pH range in which the type was expected to be dominant clearly became smaller with time. These trends support the view that the role of processes related to chance and dispersal decrease with time, while those related to environmental filtering mediated by biotic interactions increase. Conclusions: We conclude that temporal comparisons of spatially explicit habitat models provide insights into changing biotic community processes and their effects on habitat specificity of species or their communities. Thus, this approach may be particularly important for analysis of ecological systems that are not in equilibrium with their environmental drivers. 相似文献
11.
中国西南喀斯特植物群落演替特征及驱动机制 总被引:11,自引:0,他引:11
植被恢复是西南喀斯特石漠化治理和生态重建的关键步骤。通过总结已有的结果和分析中国科学院环江喀斯特试验站部分试验数据,研究了西南喀斯特植被演替过程中群落的动态特征,结果发现:西南喀斯特沿北、中、南亚热带至北热带的海拔递减、气温和降雨量升高的梯度格局下,群落的高度、盖度增加,密度、科属种数量和物种多样性呈递减趋势;不同区域沿草丛、灌丛、灌乔丛、乔丛的顺向演替方向上,群落的高度、盖度增加、密度减小,科属种数量及物种多样性除北亚热带持续增加外,其他3个区域的最大值均出现在灌乔丛,乔丛反而有所下降;西南喀斯特植被演替是生物驱动因素与环境阻力相互作用的结果,不同区域不同演替阶段植被演替的建群种和关键种不同,其植物群落的稳定性受多样性和结构性的共同控制,因地质和生态环境恶劣,植被退化容易恢复难,充分理解和认识植被演替规律对西南喀斯特植被恢复和生态重建意义重大。 相似文献
12.
Felix May Andreas Huth Thorsten Wiegand 《Proceedings. Biological sciences / The Royal Society》2015,282(1802)
Assessing the relative importance of different processes that determine the spatial distribution of species and the dynamics in highly diverse plant communities remains a challenging question in ecology. Previous modelling approaches often focused on single aggregated forest diversity patterns that convey limited information on the underlying dynamic processes. Here, we use recent advances in inference for stochastic simulation models to evaluate the ability of a spatially explicit and spatially continuous neutral model to quantitatively predict six spatial and non-spatial patterns observed at the 50 ha tropical forest plot on Barro Colorado Island, Panama. The patterns capture different aspects of forest dynamics and biodiversity structure, such as annual mortality rate, species richness, species abundance distribution, beta-diversity and the species–area relationship (SAR). The model correctly predicted each pattern independently and up to five patterns simultaneously. However, the model was unable to match the SAR and beta-diversity simultaneously. Our study moves previous theory towards a dynamic spatial theory of biodiversity and demonstrates the value of spatial data to identify ecological processes. This opens up new avenues to evaluate the consequences of additional process for community assembly and dynamics. 相似文献
13.
Spatial pattern of distribution of marine invertebrates within a subtidal community: do communities vary more among patches or plots?
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Making links between ecological processes and the scales at which they operate is an enduring challenge of community ecology. Our understanding of ecological communities cannot advance if we do not distinguish larger scale processes from smaller ones. Variability at small spatial scales can be important because it carries information about biological interactions, which cannot be explained by environmental heterogeneity alone. Marine fouling communities are shaped by both the supply of larvae and competition for resources among colonizers—these two processes operate on distinctly different scales. Here, we demonstrate how fouling community structure varies with spatial scale in a temperate Australian environment, and we identify the spatial scale that captures the most variability. Community structure was quantified with both univariate (species richness and diversity) and multivariate (similarity in species composition) indices. Variation in community structure was unevenly distributed between the spatial scales that we examined. While variation in community structure within patch was usually greater than among patch, variation among patch was always significant. Opportunistic taxa that rely heavily on rapid colonization of free space spread more evenly among patches during early succession. In contrast, taxa that are strong adult competitors but slow colonizers spread more evenly among patches only during late succession. Our findings show significant patchiness can develop in a habitat showing no systematic environmental spatial variation, and this patchiness can be mediated through different biological factors at different spatial scales. 相似文献
14.
Bruce A. Menge Gary W. Allison Terry M. Farrell Teresa A. Turner 《Journal of experimental marine biology and ecology》2005,314(1):3-39
Macrophyte mosaics, or tile-like assemblages of turfy marine macroalgae and surfgrass (Phyllospadix scouleri), are persistent and highly diverse along the central Oregon coast. To test the hypothesis that spatial pattern and species abundances are relatively invariant in this system, we studied community structure, disturbance, and species interactions from 1985 to 1990. Abundances and disturbance in permanently marked plots at each of five sites spanning wave-exposed to wave-protected areas were monitored photographically each year. The analysis was spatially explicit, incorporated position effects, and allowed determination of species displacements. To interpret the potential influence of substratum on disturbance, we quantified rock hardness and sediment depth at each site. Field experiments tested the role of grazers and spatial interactions on maintenance of between-patch boundaries.Mosaic dynamics varied with wave exposure. At wave-exposed and wave-protected sites, average patterns of abundance and assemblage structure were relatively constant through time, but analysis of transition probabilities showed high rates of change among mosaic elements at wave-exposed sites and low rates of change at wave-protected sites. At wave-exposed sites, most changes involved Phyllospadix displacing neighboring macroalgal turfs but rarely the reverse. At all wave-exposures, surfgrass was the most frequently disturbed mosaic element. Disturbed areas were quickly colonized by macroalgae. At wave-exposed sites, disturbances were closed by regrowth of surfgrass. Disturbance rates were similar across wave-exposures, with wave forces causing most loss at wave-exposed sites and a combination of substratum failure and sediment burial causing most loss at wave-protected sites. At wave-exposed sites, disturbances tended to be larger (436.7 vs. 278.6 cm2) but less numerous (228 vs. 484 total disturbances) than at wave-protected sites.At wave-exposed sites, surfgrass overgrew all other species except the kelp Lessoniopsis littoralis, which was competitively equivalent to surfgrass. Grazing had no effect on spatial interactions. Disturbance prevented surfgrass monocultures, and with variable dispersal and patchy recruitment, maintained mosaic structure. At wave-protected sites, standoffs were the usual outcome of interactions, and patchiness resulted primarily from colonization of disturbances and subsequent succession. Like mussels, Phyllospadix are simultaneously dominant competitors, the most disturbance-susceptible species, and poor colonizers. These features are shared by theoretical models exploring the processes underlying spatially structured assemblages, and may characterize spatially structured systems in general. 相似文献
15.
Nick Cutler 《Polar Biology》2011,34(5):693-706
Biological modification of the physical environment is a characteristic feature of primary succession that is of particular
importance in stressful, high-latitude habitats. However, the degree of spatiotemporal variability in biotic reaction is poorly
understood. This is a significant gap in our knowledge of primary succession, as spatiotemporal variability in biotic reaction
may be linked to divergent development during succession. The aim of this research was to infer long-term, spatiotemporal
changes in vegetation and environmental parameters during primary succession from a chronosequence of lava flows in Iceland.
Vegetation surveys and measurement of key environmental variables (temperature, relative humidity and wind speed) were carried
out on seven lava flows aged 26–848 years. The duration of snow cover was inferred from temperature data using a novel technique.
Paired measurements were taken in topographical low and high points, as previous studies in this location have indicated divergent
vegetation development according to topographical position. The analysis indicated the long-term amelioration of microclimate.
Vegetation development was associated with increased soil temperatures, decreased wind speeds and increased duration of snow-lie.
There was also evidence that microenvironmental changes paralleled changes in vegetation structure, although the relationship
varied according to the environmental parameter studied. It is likely that positive feedback between shrub development and
snow accumulation structures the vegetation on the study sites. These findings have implications for sub-arctic areas where
shrub cover is expanding due to climate change and for the development of vegetation on terrain exposed by retreating ice. 相似文献
16.
Population dynamics, disturbance, and pattern evolution: identifying the fundamental scales of organization in a model ecosystem 总被引:5,自引:0,他引:5
We used auto- and cross-correlation analysis and Ripley's K-function analysis to analyze spatiotemporal pattern evolution in a spatially explicit simulation model of a semiarid shrubland (Karoo, South Africa) and to determine the impact of small-scale disturbances on system dynamics. Without disturnities bance, local dynamics were driven by a pattern of cyclic succession, where 'colonizer' and 'successor' species alternately replaced each other. This results in a strong pattern of negative correlation in the temporal distribution of colonizer and successor species. As disturbance rates were increased, the relationship shifted from being negatively correlated in time to being positively correlated-the dynamics became decoupled from the ecologically driven cyclic succession and were increasingly influenced by abiotic factors (e.g., rainfall events). Further analysis of the spatial relationships among colonizer and successor species showed that, without disturbance, periods of attraction and repulsion between colonizer and successor species alternate cyclically at intermediate spatial scales. This was due to the spatial 'memory' embedded in the system through the process of cyclic succession. With the addition of disturbance, this pattern breaks down, although there is some indication of increasing ecological organization at broader spatial scales. We suggest that many of the insights that can be gained through spatially explicit models will only be obtained through a direct analysis of the spatial patterns produced. 相似文献
17.
A. M. Elgersma 《Biodiversity and Conservation》1998,7(2):193-206
Three main succession lines are found to occur on poor sandy soils in a blown drift sand landscape in the Netherlands. Site factors – organic matter, parent material, soil moisture regime and relief – were determined. Site types, specific combinations of these site factors, are defined. For five site types succession was studied. The primary criterion for separating succession lines and for delineating the successional stages, was the site factor organic matter and the second criterion, groundwater level. Influence of organic matter on succession was significant on site types with a buried podzol. Species composition on these site types indicated richer sites than the species composition on the site types without a buried podzol. Groundwater level of about 1m with gleyzone was critical for species requiring moist sites. Within a succession line vegetation stages are characterized and the potential forest type is presumed. The stages were related to humus form and soil development. Litter of dominant species was suggested to be the main criterion for the humus form. Initial and older vegetation stages were linked to development of soil horizons. The defined site types, their soil development and relationships with the succession lines clarify spatial and temporal structure and diversity of vegetation, and herewith is the basic information for clarifying the heterogeneity and potential biodiversity of this blown drift sand landscape. 相似文献
18.
19.
Competitive exclusion and habitat filtering influence community assembly, but ecologists and evolutionary biologists have not reached consensus on how to quantify patterns that would reveal the action of these processes. Currently, at least 22 α‐diversity and 10 β‐diversity metrics of community phylogenetic structure can be combined with nine null models (eight for β‐diversity metrics), providing 278 potentially distinct approaches to test for phylogenetic clustering and overdispersion. Selecting the appropriate approach for a study is daunting. First, we describe similarities among metrics and null models across variance in phylogeny size and shape, species abundance, and species richness. Second, we develop spatially explicit, individual‐based simulations of neutral, competitive exclusion, or habitat filtering community assembly, and quantify the performance (type I and II error rates) of all 278 metric and null model combinations against each assembly process. Many α‐diversity metrics and null models are at least functionally equivalent, reducing the number of truly unique metrics to 12 and the number of unique metric + null model combinations to 72. An even smaller subset of metric and null model combinations showed robust statistical performance. For α‐diversity metrics, phylogenetic diversity and mean nearest taxon distance were best able to detect habitat filtering, while mean pairwise phylogenetic distance‐based metrics were best able to detect competitive exclusion. Overall, β‐diversity metrics tended to have greater power to detect habitat filtering and competitive exclusion than α‐diversity metrics, but had higher type 1 error in some cases. Across both α‐ and β‐diversity metrics, null model selection affected type I error rates more than metric selection. A null model that maintained species richness, and approximately maintained species occurrence frequency and abundance across sites, exhibited low type I and II error rates. This regional null model simulates neutral dispersal of individuals into local communities by sampling from a regional species pool. We introduce a flexible new R package, metricTester, to facilitate robust analyses of method performance. 相似文献
20.
Primary plant succession was investigated on a well-vegetated glacier foreland on Ellesmere Island in high arctic Canada.
A field survey was carried out on four glacier moraines differing in time after deglaciation to assess vegetation development
and microsite modification in the chronosequence of succession. The results showed evidence of directional succession without
species replacement, which is atypical in the high arctic, reflecting the exceptionally long time vegetation development.
During this successional process, Salix arctica dominated throughout all moraines. The population structures of S. arctica on these moraines implied the population growth of this species with progressing succession. The population density of S. arctica reflected the abundance of vascular plants, suggesting that development of the plant community might be related to structural
changes and the growth of constituting populations. Through such growths of the population and the whole community with progressing
succession, the spatial heterogeneity of vegetation gradually declines. Moreover, this vegetation homogenization is accompanied
by changes in the spatial heterogeneity of microsite environments, suggesting significant plant effects on the modification
of microsite environments. Accordingly, it was concluded that the directional primary succession observed on this glacier
foreland is characterized by the initial sporadic colonization of plants, subsequent population growths, and the community
assembly of vascular plants, accompanied by microsite modification. 相似文献