Changes in Forest Structure and Species Composition during Secondary Forest Succession in the Bolivian Amazon1

Changes in forest structure and species diversity throughout secondary succession were studied using a chronosequence at two sites in the Bolivian Amazon. Secondary forests ranging in age from 2 to 40 years as well as mature forests were included, making a total of 14 stands. Fifty plants per forest layer (understory, subcanopy, and canopy) were sampled using the transect of variable area technique. Mean and maximum height, total stem density, basal area, and species number were calculated at the stand level. Species diversity was calculated for each stand and for each combination of forest layer and stand. A correspondence analysis was performed, and the relationship between relative abundance of the species and stand age was modeled using a set of hierarchical models. Canopy height and basal area increased with stand age, indicating that secondary forests rapidly attain a forest structure similar in many respects to mature forests. A total of 250 species were recorded of which ca 50 percent made up 87 percent of the sampled individuals. Species diversity increased with stand age and varied among the forest layers, with the lowest diversity in the canopy. The results of the correspondence analysis indicated that species composition varies with stand age, forest layer, and site. The species composition of mature forests recovered at different rates in the different forest layers, being the slowest in the canopy layer. Species showed different patterns of abundance in relation to stand age, supporting the current model of succession.     

Vegetation convergence during early succession on coal wastes: a 6‐year permanent plot study

Question: Does the course of succession on a coal mine restored by hydroseeding converge with a reference community in terms of species composition and vegetation structure? What is the rate of succession on restored areas? How does the balance between local colonization and extinction rates change during succession? Which species group (native or hydroseeded) determines the successional process? Location: Large reclaimed coal mine in the north of Palencia province, northern Spain (42°50′N, 4°38′W). Methods: Between 2004 and 2009 we monitored annually vascular plant species cover in nine permanent plots (20 m² each) at a restored mine; these plots were structured to account for site aspect (north, south and flat). Three identical permanent plots were established in the surrounding reference community and monitored in 2004 and 2009. We used detrended correspondence analysis to assess successional trends and rates of succession, generalized linear mixed models to derive patterns of vegetation structural changes and turnover through time, and Huisman–Olff–Fresco modelling to illustrate response of individual species through time. Results: The three restored mine areas exhibited a successional trend towards the reference community through time, although speed of convergence differed. However, after 6 years the restored sites had diverged considerably and this was greater than the dissimilarity reduction with respect to the reference community. Richness, diversity and native species cover increased linearly through time, whereas hydroseeded species cover decreased. Success of hydroseeded species initially differed in the three areas, and this was negatively related with native species colonization rates. Response patterns through time of ten hydroseeded and 20 most common native species are described. Conclusions: Vegetation structural parameters rapidly converged with the reference community, whereas compositional convergence needed much longer. At the same time, successional composition trajectories and rates were related to site properties (here aspect).     

贡嘎山冰川退缩区植物-土壤反馈与植物间相互作用

植物-土壤反馈是揭示陆地生物群落动态变化的关键环节,为理解植物间相互作用及植被群落变化过程奠定基础。本研究以贡嘎山冰川退缩区原生演替早(5~10年)、中(30~40年)和晚期(80~100年)3个阶段典型土壤以及各阶段优势植物为对象,采用盆栽控制试验,比较优势植物在不同土壤条件下的生物量,并量化植物间相互作用以及植物-土壤反馈的方向与强度,为探究贡嘎山冰川退缩区植被群落演替规律提供依据。结果表明:(1)植物-土壤反馈作用显著影响植物在本土中的生物量,早期沙棘(Hippophae rhamnoides)在本土中生长最差,沙棘的植物-土壤反馈系数为负值;演替中期冬瓜杨(Populus purdomii)的反馈系数趋于零;晚期峨眉冷杉(Abies fabri)在本土中生长最好,峨眉冷杉的反馈系数为正值。(2)混种时,早期沙棘与演替中、晚期植物间相互作用指数为负值;中期冬瓜杨、川滇柳(Salix rehderiana)与演替早、晚期植物的相互作用指数接近于零,晚期植物峨眉冷杉、麦吊云杉(Picea brachytyla)与演替早、中期植物相互作用指数为正值。从植物-土壤反馈的方向来看,贡嘎山植被演替从早期负反馈,中期中性反馈,过渡到晚期正反馈。此外,演替早期沙棘促进演替中晚期植物生长,演替中期冬瓜杨、川滇柳对演替早晚期植物无显著影响,晚期峨眉冷杉、麦吊云杉更利于与演替早中期植物相互竞争。结果显示,植物-土壤反馈与植物间相互作用共同驱动了贡嘎山冰川退缩区植被快速演替,直至顶极群落。     

Woody plant encroachment impacts on soil carbon and microbial processes: results from a hierarchical Bayesian analysis of soil incubation data

Quantitative methods were used to examine soil properties and their spatial heterogeneity in a 0-year fenced mobile dune (MD0), an 11-year fenced mobile dune (MD11) and a 20-year fenced mobile dune (MD20) in Horqin Sandy Land, Northern China. The objective of the study was to assess the effect of vegetation restoration on heterogeneity of soil properties in sand dunes and to provide a concept model to describe the relationship between vegetation succession and spatial heterogeneity variation of soil properties in the dunes. The results showed that the average values of vegetation cover, species number and diversity, soil organic carbon (C), total nitrogen (N), and electrical conductivity (EC) increased with the increase in fenced age of mobile dunes, while soil water content (0–20 cm) showed the reverse trend. Geostatistical analysis revealed that the spatial heterogeneity of soil organic C, total N, EC, very fine sand content, and soil water content (0–20 cm) increased from MD0 to MD11 with succession from sand pioneer plant to shrub species then decreased from MD11 to MD20 due to continuous development of herbaceous plants. Canonical correspondence analysis (CCA) showed that there was a relatively high correspondence between vegetation and soil factors, suggesting that the major gradients relating soil organic C, total N, EC, pH, slope, very fine sand content, and soil water content are the main factors for the distribution of dune plants and account for 68.1% of the species-environment relationship among the three sites. In addition, the distribution of the sand pioneer plant was positively related to the relative height of the sampling site and soil water content, and that of most herbaceous plants were determined by soil organic C, total N, EC, pH, and very fine sand content in mobile dunes. The conceptual model of relationship between vegetation succession and spatial heterogeneity of soil properties in mobile dunes suggests spatial patterns of soil properties are most strongly related to plant-induced heterogeneity in dune ecosystems prone to wind erosion, and conversely, the magnitude and degree of spatial heterogeneity in soil properties can influence the plant distribution pattern and vegetation succession of mobile dunes.     

Field observed relationships between biodiversity and ecosystem functioning during secondary succession in a tropical lowland rainforest

The relationship between biodiversity and ecosystem functioning (BEF) is one of the most concerned topics in ecology. However, most of the studies have been conducted in controlled experiments in grasslands, few observational field studies have been carried out in forests. In this paper, we report variations of species diversity, functional diversity and aboveground biomass (AGB) for woody plants (trees and shrubs) along a chronosequence of four successional stages (18-year-old fallow, 30-year-old fallow, 60-year-old fallow, and old-growth forest) in a tropical lowland rainforest recovered after shifting cultivation on Hainan Island, China. Fifty randomly selected sample plots of 20 m × 20 m were investigated in each of the four successional stages. Four functional traits (specific leaf area, wood density, maximum species height and leaf dry matter content) were measured for each woody plants species and the relationships between species/functional diversity and AGB during secondary succession were explored. The results showed that both plant diversity and AGB recovered gradually with the secondary succession. AGB was positively correlated with both species and functional diversity in each stage of succession. Consistent with many controlled experimental results in grasslands, our observational field study confirms that ecosystem functioning is closely related to biodiversity during secondary succession in species rich tropical forests.     

高寒牧区中华羊茅人工草地退化演替的数量特征研究

对中华羊茅人工草地退化演替数量特征的研究表明,植物群落组分种的数量、丰富度指数、多样性指数和均匀度指数均随演替的进程而增加,生态优势度指数呈下降趋势。对25个组分种的重要值、生态位宽度及生态位重叠值计测的结果表明,一些阔叶杂草（如细叶亚菊、西伯利亚蓼等）是退化演替过程中入侵人工草地的先锋植物,比其他杂类草具有较大的生态位宽度值,其重要值在演替过程中呈逐年上升趋势。以中华羊茅为其中一个组分种的植物种对间的生态位重叠值,在大多数情况下小于两种阔叶杂草种对间的生态位重叠值。阔叶杂草入侵是导致人工草地退化的一个重要影响因素。     

Early succession on lahars spawned by Mount St. Helens

The effects of isolation on primary succession are poorly documented. I monitored vegetation recovery on two Mount St. Helens lahars (mud flows) with different degrees of isolation using contiguous plots. Seventeen years after the eruption, species richness was stable, but cover continued to increase. That isolation affects community structure was confirmed in several ways. The dominance hierarchies of the lahars differed sharply. Detrended correspondence analysis on Lahar I showed a trend related to distance from an adjacent woodland, whereas vegetation on Lahar II was relatively homogeneous. Spectra of growth forms and dispersal types also differed. Lahar I was dominated by species with modest dispersal ability, while Lahar II was dominated by species with better dispersal. Variation between plots should decline through time, a prediction confirmed on Lahar II. Lahar I remained heterogeneous despite having developed significantly higher cover. Here, the increasing distance from the forest has prevented plots from becoming more homogeneous. At this stage of early primary succession, neither lahar is converging towards the species composition of adjacent vegetation. This study shows that isolation and differential dispersal ability combine to determine initial vegetation structure. Stochastic effects resulting from dispersal limitations may resist the more deterministic effects of competition that could lead to floristic convergence.     

黑龙江省东部矿区鸟类群落多样性的比较分析

2007年12月至2009年2月,采用样线法和样方法对黑龙江东部4个主要矿区(鸡西、鹤岗、双鸭山和七台河矿区)的鸟类群落多样性进行了调查,共记录到鸟类16目36科107种。其中古北种50种,东洋种11种,广布种46种;留鸟22种,夏候鸟64种,冬候鸟1种,旅鸟20种;国家Ⅰ级重点保护鸟类1种,国家Ⅱ级重点保护鸟类13种。4个矿区中以鸡西矿区的鸟类多样性和均匀性最高,鹤岗最低,这与煤矸石的堆积、采矿方式,以及矿区生境类型、植被演替等有关。在植被演替的不同阶段鸟类多样性存在差异,处于演替中期的针阔混交林中鸟类多样性最高,处于演替早期的阔叶林最低。     

西双版纳勐宋轮歇演替区鸟类多样性及食果鸟研究

结合退耕还林、生态保护和山区经济持续发展的需要,在西双版纳勐宋轮歇休闲自然演替林地、传统保护使林地和原始自然林地等3类8种生境中,采用样方法并辅以挂网捕鸟法,研究了鸟类的多样性、食果鸟类及其与森林动态的关系。结果表明：①随着轮歇休闲时间递增和植被层次增加,鸟类多样性增加,鸟类群落逐渐复杂化;②鸟类多样性H、Hmax和J等参数变化情况在干季和雨季类似;③食果传播植物种子的鸟类沟通了各林地之间的联系,它们的活动对植被的演替和扩展至关重要。讨论分析认为,鸟类多样性与生境植被结构相互作用,协同发展;在退耕还林工作中要重视食果类及其生态功能的作用,注意保护原始森林和鸟类物种,利用和促进食果鸟类的自然生态功能。     

Early plant succession in two abandoned cut-over peatland areas

Initial stages of plant succession (from 0 to 8 or 9 yr) were studied on abandoned peat harvest sites of two adjacent areas in Finland. At the Mustasuo area only 13 field layer species, all perennials, and 3 ground layer species became established during that period and species composition stayed relatively constant. All species occurred sparsely with low biomass. The Riitasuo area was colonized by 43 field layer and 19 ground layer species during the first 8 yr of succession. In that area the originally plantless sites were totally covered by plants within a few years. Many of the first species to arrive were annuals, most of which were soon replaced by perennial species. The great differences between the two areas in the rate and pattern of early succession are suggested to arise from differences in the seed sources and in the physical and chemical characteristics of the soil. The areas were found to differ especially by the thickness of the remaining peat layer, by the particle size distribution of the peat soil and by the contents of nitrate and ammonium nitrogen of the soil.     

Patterns in woody species diversity, richness and partitioning of diversity in forest communities of tropical deciduous forest biome

The regressive succession model hypothesizes tropical savanna-woodlands to be a degraded stage of primary deciduous forests. Species diversity, richness and evenness of woody species in savanna-woodlands, secondary deciduous forests and mature deciduous forests of central India were compared to test if the regressive succession explained pattern in species richness, diversity, functional diversity and basal area. At the plot scale (0.1 ha) secondary deciduous forests and savanna-woodlands had similar species diversity, a pattern not consistent with the regressive model of deciduous forest succession, and mature deciduous forests had greater species diversity and richness (p<0.05). When examined at a larger scale or community scale by pooling all plots within a community type, the trend in diversity persisted even with greater effort allocated to sampling of secondary deciduous forests. Species richness at the community scale was greatest in secondary deciduous forest as expected from species area relationship. The communities shared 28 woody species but the species composition was significantly different between the communities. I suggest that conservation of tropical deciduous forests based on regressive succession model is problematic.     

Vegetation dynamics in the fens of Chautagne (Savoie,France) after the cessation of mowing

The mechanisms controlling secondary succession on eutrophic peat are analyzed on an area of 500 ha marsh near the Lac du Bourget in the Rhône floodplain between Geneva and Lyon. After describing the succession, the authors compare the succession with that described for fens in England.During succession, three categories of phenomena occur:-Predictable phenomena based on the occurrence of well-established relationships between species with a high cover density. When mowing ceases, populations with increasingly higher biomasses reach dominance one by one.-Phenomena which were to be expected although the manner in which they occurred were more difficult to predict, such as the conditions in which woody plants take over.-Phenomena hidden in the framework of a synchronic analysis. The lowering of the water table, for example, can modify the entire community of species occurring in the sequence as well as the competition between species. The pecularities of each type of ecological situation made it difficult to develop general models.     

Community succession and photosynthetic physiological characteristics of pasture plants in a sub-alpine meadow in Gannan,China

 为了解甘南亚高山草甸围封地恢复演替动态, 探究围封恢复进程中植物光合生理特征的变化规律及其影响因子, 对围封试验地内5个典型群落样地进行样方调查, 测定了各群落优势种及3个共有种的光合参数和叶性状参数, 并测定了群落表层土壤(0–20 cm)的水分含量及全氮含量。结果显示: 该围封地内形成一个以草本植物→半灌木→灌木的演替序列, 群落表层土壤含水量及全氮含量随着演替的进行逐渐增加; 在演替的时间尺度上, 各演替阶段优势种光合生理特征间存在明显差异, 随着演替的进行, 群落优势种的净光合速率(A_area)、光合水分利用效率(WUE)、相对叶绿素含量(SPAD)呈降低趋势, 其叶片氮含量(N_mass)、光合氮利用效率(PNUE)、比叶面积(SLA)随演替变化没有严格一致的规律, 而更多地表现为不同植物功能型之间的差异; 从演替前期到后期, 同种植物的A_area、SPAD值逐渐降低, 非豆科植物披碱草(Elymus dahuricus)、老鹳草(Geranium wilfordii)的PNUE、WUE随演替进行呈降低趋势, 其N_mass、SLA随演替进行却呈增加趋势, 然而豆科植物紫苜蓿(Medicago sativa)由于具有固氮能力, 受养分限制不明显, 这些光合生理特征值没有随演替发生明显的变化。这些结果表明, 在恢复演替过程中, 该围封地由一个物质获得能力强的群落向物质保持能力强的群落过渡, 土壤水分含量及全氮含量是推动这种过渡发生的主要因子。掌握围封地群落演替过程中的光合生理动态对于亚高寒退化草甸恢复具有一定的理论指导意义。     

盐城自然保护区海滨湿地植被演替的生态机制

研究选取盐城自然保护区核心区典型湿地作为参照,对其海滨湿地植物群落的自然演替以及利用生态工程方法控制外来种互花米草(Spatina alterniflora)的生态学机理进行了研究.利用空间替代时间的方法,采取主分量分析和多元线性回归相结合的分析手段,对采集的相关环境参量数据进行分析,建立了海滨湿地植被自然演替的模型.模型表明,在海滨湿地植被的自然演替过程中,水分、盐度、土壤养分都起到了重要的作用,同时种间竞争也发挥了巨大的作用.不同演替阶段各因素的影响大小各不相同.在模型的基础上分析了演替过程中环境因子与3种主要优势物种之间以及物种与物种之间的相互作用关系.     

Settlement patterns of species in a marine fouling community and some mechanisms of succession

The succession of fouling organisms that settled on asbestos plates immersed at Garden Island. Western Australia, was partially caused by the settlement patterns of the species involved. Both temporal variations in the abundance and continuity of settlement of each species and the age of the communities in which each species settled abundantly contributed to producing the succession. Additionally, temporal variations in the settlement of each species probably resulted in variability in the pattern of succession.Balanus and Spirorbis, the two earliest species in the succession, settled continuously and abundantly so that they immediately occupied a substantial area. The species which predominated later in the succession, Anomia, Ostrea, encrusting bryozoans, and Mytilus, settled discontinuously so that they were unlikely to settle immediately on a newly immersed surface. Additionally, Anomia, Ostrea, and the encrusting bryozoans did not settle abundantly and did not occupy a substantial area while small. Thus, there was also a delay between the time when these species settled and the time when they had grown sufficiently large to occupy a substantial area.Mytilus was the only species that settled abundantly in established communities and thus could persist indefinitely in a community. Settlement of the other species which occurred earlier in the succession was largely restricted to newly immersed plates and consequently these species were limited in their duration in the succession by the life-spans of the individual organisms.     

Succession of terrestrial macrofungi along a deglaciation gradient at Glacier Blåisen, South Norway

A survey of terrestrial macrofungi along a deglaciation gradient from the glacier forefront to the established vegetation has been performed. The study was accomplished along a transect from Lake Finsevann to Glacier Blåisen, South Norway. Fortysix 6 m × 6 m plots divided into 9 subplots were positioned along this transect. The frequency of fruit bodies of each species in each plot was given on a 0–9 scale reflecting their occurrence in the subplots. Biotic and abiotic environmental variables for the plots were also recorded. The numerical methods used include principal component analysis (PCA), detrended correspondence analysis (DCA), and canonical correspondence analysis (CCA). Totally 99 species of macrofungi were recorded; 80.8 % of the species belonged to the Basidiomycota and 19.2 % to the Ascomycota. About one third of the species was only found once. In general, the species richness was highest on the glacier forefront, lowest in the most established vegetation. The proportion of species of Ascomycota was highest close to the glacier front. The main gradient in the data set was shown related to the primary ecological succession following the retreat of glaciers. The second gradient was possibly related to fine scale variation due to local moisture, microtopography, and secondary distribution. Of the variation in composition of species, 3 % can be ascribed to abiotic variance, 10 % to vascular plant variance, and 16 % to the combination of the abiotic and vascular plant component of variation. The results are discussed in the light of the time since deglaciation and the influence of certain biotic and abiotic environmental factors.     

Grassland butterfly communities of the Western Siberian forest steppe in the light of post-Soviet land abandonment

Land-use change and homogenization of the landscape are severe threats to butterfly diversity. The break-up of the Soviet Union in 1991 led to land abandonment on very large scales. This study aims at assessing the impact of the ongoing abandonment of traditionally managed grasslands and subsequent vegetation succession on butterflies in Western Siberia, a species-rich area with butterfly communities similar to those of Central and Eastern European grasslands. 20 mown and 20 abandoned grasslands were surveyed using Distance Sampling methods in summer 2015. We recorded 997 individuals from 44 species, pooled over two sampling events. An indicator species analysis and detrended correspondence analysis revealed that communities likely underwent changes in species composition during succession, and that habitat specialization decreased. In contrast to previous studies we found no evidence of early stages of abandonment being more species-rich than mown meadows. On unmanaged grasslands litter cover and litter depth were significantly higher than on mown grasslands. Half of the abandoned sites were riparian meadows. The dynamics and ecological characteristics of the floodplain had a stronger influence on community composition than land use. This study shows that structural heterogeneity and lepidopteran diversity of the vast, but understudied, Western Siberian grasslands are driven by mechanic and natural disturbance. Conservation should aim at responding to trends of abandonment and actively maintaining a mosaic with grasslands of different successional stages.     

SPECIES-AREA RELATIONSHIP DURING PRIMARY SUCCESSION IN GRANITE OUTCROP PLANT COMMUNITIES

The species-area relationship and its underlying explanatory mechanisms were investigated in a primary successional sere on a southeastern (United States) granite outcrop. There, plant communities occupy soil-filled depressions separated from one another by areas of bare rock. They have been termed “island communities.” Soil depth and area increase as succession proceeds from Sedum smallii, to lichen-annual, to annual-perennial, and to herb-shrub-tree stages. Although plant species richness is significantly and positively correlated with island area in the system studied (all successional stages considered), the relationship between species richness and island maximum soil depth is stronger. However, island maximum soil depth and area are significantly and positively correlated. The exponential function describes the speciesarea relationship better than the transformed power function. Within successional stage, species richness shows no significant relationship with area or depth, except for late-successional island communities. Processes related to community successional development may explain the species-area relationship that exists when islands of all stages are considered. However, mechanisms related to equilibrium between extinction and immigration may be responsible for the speciesarea relationship for late-successional island communities.     

浙南近海头足类种类组成及生态位分析

在浙南海域布设42个调查站位,于2015年1 1月、2016年2月、5月和8月进行了4个航次的系统调查.针对获得的头足类样品,运用相对重要性指数、生态位宽度和生态位重叠等生态指标,结合非度量多维标度法(nMDS)和典范对应分析(CCA)对生态位的重叠和分化进行分析.结果 表明:调查海域有头足类14种,优势种为剑尖枪乌贼...