Forest plant community as a driver of soil biodiversity: experimental evidence from collembolan assemblages through large‐scale and long‐term removal of oak canopy trees Quercus petraea

Plant–soil interactions are increasingly recognized to play a major role in terrestrial ecosystems functioning. However, few studies to date have focused on slow dynamic ecosystems such as forests. As they are vertically stratified by multiple vegetation strata, canopy tree removal by thinning operations could alter forest plant community through tree canopy opening. Very little is known about cascading effects on soil biodiversity. We conducted a large‐scale, multi‐site assessment of collembolan assemblage response to long‐term canopy tree removal in sessile oak Quercus petraea temperate forests. A total of 33 experimental plots were studied covering a large gradient of canopy tree basal area, stand age and local abiotic contexts. Collembolan abundance strongly declined with canopy tree removal in early forest successional stage and this was mediated by negative effect of understory plant community composition changes, i.e. shift from moss and forb to tree seedling, fern, shrub and grass species. Negative effect of this composition shift on collembolan species richness was largely offset by positive effect of the increase in understory plant species richness. This gives support to both the plant mass‐ratio and functional diversity hypotheses. Collembolan functional groups had contrasting response patterns, which were mediated by different ecological factors. Epedaphic (r‐strategist) abundance and species richness increased with canopy tree removal in relation with the increase in understory plant species richness. In contrast, euedaphic (K‐strategist) abundance and species richness declined with canopy tree removal in early forest successional stage in relation with changes in understory plant community composition and species richness, as well as microclimatic conditions. Overall, our study provides experimental evidence that forest plant community can be a strong driver of collembolan assemblages. It also emphasizes the role of trees as foundation species of forest ecosystems that can shape soil biodiversity through their regulation of understory plant community and ecosystem abiotic conditions.     

Species richness and soil properties in Pinus ponderosa forests: A structural equation modeling analysis

Question: How are the effects of mineral soil properties on understory plant species richness propagated through a network of processes involving the forest overstory, soil organic matter, soil nitrogen, and understory plant abundance? Location: North‐central Arizona, USA. Methods: We sampled 75 0.05‐ha plots across a broad soil gradient in a Pinus ponderosa (ponderosa pine) forest ecosystem. We evaluated multivariate models of plant species richness using structural equation modeling. Results: Richness was highest at intermediate levels of understory plant cover, suggesting that both colonization success and competitive exclusion can limit richness in this system. We did not detect a reciprocal positive effect of richness on plant cover. Richness was strongly related to soil nitrogen in the model, with evidence for both a direct negative effect and an indirect non‐linear relationship mediated through understory plant cover. Soil organic matter appeared to have a positive influence on understory richness that was independent of soil nitrogen. Richness was lowest where the forest overstory was densest, which can be explained through indirect effects on soil organic matter, soil nitrogen and understory cover. Finally, model results suggest a variety of direct and indirect processes whereby mineral soil properties can influence richness. Conclusions: Understory plant species richness and plant cover in P. ponderosa forests appear to be significantly influenced by soil organic matter and nitrogen, which are, in turn, related to overstory density and composition and mineral soil properties. Thus, soil properties can impose direct and indirect constraints on local species diversity in ponderosa pine forests.     

Plant succession in areas of scorched and blown-down forest after the 1980 eruption of Mount St. Helens,Washington

Abstract. Patterns of plant succession were studied in areas of scorched and blown-down forest resulting from the 1980 eruption of Mount St. Helens, Washington. Changes in species abundance were observed for 7 years in permanent sample plots representing four post-disturbance habitats, or site types. Total plant cover and species richness increased with time on all site types. In blown-down forests supporting snowpack at the time of eruption, understory recovery was dominated by the vegetative regeneration of species persisting through disturbance. In forests without snowpacks, plant survival was poorer. Increases in cover and diversity were dominated first by introduced grasses, then by colonizing forbs characteristic of early successional sites. Epilo-bium angustifolium and Anaphalis margaritacea showed widespread recruitment and clonal expansion throughout the devastated area. As a result, species composition on previously forested sites converged toward that on formerly clearcut sites, where early serai forbs resprouted vigorously from beneath the tephra. Total plant cover and species diversity were poorly correlated with post-disturbance habitat and general site characteristics (e.g. distance from the crater, elevation, slope, and aspect). However, distributions of several life-forms (e.g. low sub-shrubs and tall shrubs) were strongly correlated with depth of burial by tephra and with cover of tree rootwads. Thus, early community recovery may reflect microsite variation or chance survival and recruitment rather than broad-scale gradients in environment or disturbance. Recovery of pre-disturbance composition and structure will undoubtedly be much slower than after other types of catastrophic disturbance. The rate and direction of community recovery will largely depend on the degree to which original understory species survived the eruption.     

SEEDLING ESTABLISHMENT IN FORESTS AFFECTED BY TEPHRA FROM MOUNT ST. HELENS

Seedling density on permanent plots at five sites was monitored for the first four summers following the deposition of 4.5 to 15 cm of tephra from the 1980 eruption of Mount St. Helens. Because the old-growth forests at the sites were not destroyed by the volcanic eruption, the plots were under a normal tree canopy. Almost no seedlings established in 1980. By 1983 tree seedling density exceeded 35 m^−-2 at all sites. Tsuga heterophylla seedlings were most common, with Abies amabilis seedlings next in abundance. A dense layer of small trees may develop on the tephra and long-term forest dynamics could be affected. There was no successful invasion by species not already present in the stands. Seedlings of some forest herbs, especially Tiarella trifoliata, were common, but many other common forest species produced none. It is still problematical if or when these species will return to areas of the forest from which they were extirpated.     

Direct effects of tephra fallout from the Puyehue–Cordón Caulle Volcanic Complex on Nothofagus pumilio ring widths in northern Patagonia

We evaluated the radial growth response of adult Nothofagus pumilio (Poepp. et Endl) Krasser trees affected by tephra deposition following historical volcanic eruptions of the Puyehue–Cordón Caulle Volcanic Complex (PCCVC) in northern Patagonia. Standard tree–ring width chronologies were developed for trees from two sites that were affected by up to 55 cm of tephra during the 2011 eruption, which allowed us to detect the general tree–growth response to eruptions VEI ≥ 3 and VEI ≤ 2. The tree growth trend satisfactorily followed the mean temperature record (r = 0.42); however, the analysis of studentized residuals identified outliers (≥ ± 2 SD) directly related to the volcanic eruptions of the years 1921–1922 and 2011 and the respective post–eruption years, while for the 1960 eruption and following year, they largely exceeded the mean value of the residuals. The large amount of tephra deposited during the 1921–22 and 2011 eruptions caused physical damage to the tree canopy leading to the appearance of white rings and to locally absent rings. The rate of change in radial growth of trees during these eruptions presented significant declines in relation to the growth of five years before the eruption and to the following year. The low amount of tephra deposited during the 1960 eruption did not cause damage to the stands and trees increased their radial growth. In general, trees that had reduced radial growth experienced a remarkable recovery starting in the second or third post–eruption year. The amount of tephra deposited and the time of year of the volcanic eruptions had an important influence on tree rings. Some ecophysiological causes that could explain the growth responses of N. pumilio to tephra fall are discussed herein. Our study may provide useful insights to clarify the uncertain characteristics of some eruptions in the past or to detect the occurrence of large, undocumented volcanic eruptions throughout the Andes.     

Seedling and Sapling Dynamics of Treefall Pits in Puerto Rico1

Seedling and sapling dynamics in a Puerto Rican rain forest were compared between forest understory and soil pits created by the uprooting of 27 trees during Hurricane Hugo. Soil N and P, organic matter, and soil moisture were lower and bulk densities were higher in the disturbed mineral soils of the pits than in undisturbed forest soils ten months after the hurricane. No differences in N and P levels were found in pit or forest soils under two trees with N–fixing symbionts (Inga laurina and Ormosia krugii) compared to soils under a tree species without N–fixing sym–bionts (Casearia arborea), but other soil variables (Al, Fe, K) did vary by tree species. Forest plots had greater species richness of seedlings (<10 cm tall) and saplings (10–100 cm tall) than plots in the soil pits (and greater sapling densities), but seedling densities were similar between plot types. Species richness and seedling densities did not vary among plots associated with the three tree species, but some saplings were more abundant under trees of the same species. Pit size did not affect species richness or seedling and sapling densities. Recruitment of young Cecropia schreberiana trees (>5 m tall) 45 months after the hurricane was entirely from the soil pits, with no tree recruitment from forest plots. Larger soil pits had more tree recruitment than smaller pits. Defoliation of the forest by the hurricane created a large but temporary increase in light availability. Recruitment of C. schreberiana to the canopy occurred in gaps created by the treefall pits that had lower soil nutrients but provided a longer–term increase in light availability. Treefall pits also significantly altered the recruitment and mortality of many understory species in the Puerto Rican rain forest but did not alter species richness.     

Effect of tephra depth on vegetation development in areas affected by volcanism

Plant establishment on sites affected by major volcanic disturbances is limited by several factors, such as lack of suitable microsites for germination and establishment in sites affected by tephra from volcanic eruptions. Even after long periods of time, tephra deposited over un-vegetated areas (agricultural fields and other barren areas) lack closed vegetation cover and in many cases late successional species. To assess limiting factors for plant establishment, a field survey in a tephra deposit from the Paricutin volcano eruption (19°30′42.4′′ N, 102°12′03.0′′) and greenhouse experiments were carried out. The field survey determined the relationship between tephra depth and vegetation distribution. Greenhouse experiments determined the effect of tephra depth on establishment and growth of two dominant species in the tephra deposit surveyed, Eupatorium glabratum and Lupinus elegans. Our results suggest that size and spatial distribution of vegetation patches is related to tephra depth in the field (77% of the vegetation patches were on tephra 38.8 cm deep or less and only 2% on tephra of more than 46.8 cm). Under greenhouse conditions, Eupatorium glabratum and Lupinus elegans height sharply decreased as depth of the tephra layer increased. Lupinus elegans plants growing in tephra less than 30 cm deep had a mean weight of 10.56 g (±0.53 g) compared with 3.11 g (±0.46 g) for plants growing in tephra more than 30 cm deep. Our results suggest that tephra depth is a limiting factor for canopy development in barren areas affected by tephra deposition.     

Linking dominant Hawaiian tree species to understory development in recovering pastures via impacts on soils and litter

Large areas of tropical forest have been cleared and planted with exotic grass species for use as cattle pasture. These often remain persistent grasslands after grazer removal, which is problematic for restoring native forest communities. It is often hoped that remnant and/or planted trees can jump‐start forest succession; however, there is little mechanistic information on how different canopy species affect community trajectories. To investigate this, I surveyed understory communities, exotic grass biomass, standing litter pools, and soil properties under two dominant canopy trees—Metrosideros polymorpha (‘ōhi‘a) and Acacia koa (koa)—in recovering Hawaiian forests. I then used structural equation models (SEMs) to elucidate direct and indirect effects of trees on native understory. Native understory communities developed under ‘ōhi‘a, which had larger standing litter pools, lower soil nitrogen, and lower exotic grass biomass than koa. This pattern was variable, potentially due to historical site differences and/or distance to intact forest. Koa, in contrast, showed little understory development. Instead, data suggest that increased soil nitrogen under koa leads to high grass biomass that stalls native recruitment. SEMs suggested that indirect effects of trees via litter and soils were as or more important than direct effects for determining native cover. It is suggested that diverse plantings which incorporate species that have high carbon to nitrogen ratios may help ameliorate the negative indirect effects of koa on natural understory regeneration.     

冠层结构和光环境的时空变化对紫耳箭竹种群特征的影响

选择金佛山国家自然保护区内落叶阔叶林、常绿落叶阔叶混交林、常绿阔叶林3种典型群落类型,研究冠层结构和光环境特征,以及林下优势种--紫耳箭竹的种群特征.结果表明: 随着落叶阔叶林→常绿落叶阔叶混交林→常绿阔叶林的演替,Shannon多样性指数、Simpson优势度指数和Pielou指数呈增加趋势,表明群落趋于稳定发展的状态;冠层结构特征也发生了显著改变,冠层开度和平均叶倾角减小,叶面积指数增加,冠层的消光能力增强,林下光照水平降低.上层林冠是造成林型郁闭的主要原因,其中冠层厚度和冠层面积是2个主要的影响因素.冠层结构与林下光照指标显著相关,对林下散射光的影响最大.冠层开度、林下光照条件均随着生长季的到来而下降,而叶面积指数呈现增长的趋势,峰值出现在6、7月;平均叶倾角在春季达到最大值,在夏季为最小值.紫耳箭竹的生长与冠层结构和光环境密切相关,其在光照适中的常绿落叶阔叶混交林中生长得最好,分株粗壮、密度大(29.69±1.68株·m^-2),地下茎拓展能力强;落叶阔叶林中的强光环境可能造成土壤水分缺失,从而对其生长产生影响;而在常绿阔叶林的低光环境下紫耳箭竹分株矮小,密度小(5.80±1.16株·m^-2),克隆扩展能力降低.在森林结构演变的过程中,冠层结构发生了明显的改变,显著影响林下光环境,过度的低光环境对紫耳箭竹种群的更新和发展有限制作用.     

桉树人工林更新方式对林下植物功能群的影响

该研究综合运用野外调查和室内分析的方法,评估桉树人工林林下植物功能群的组成、分布及更新方式和相关环境因子之间的关系。结果表明:林分更新5 a后,除了非禾本科杂草功能群外,其他林下植物功能群的物种丰富度均呈现不同程度的增加,但与对照组(砍伐迹地)相比,其差异程度均不显著(P0.05);与对照组相比,藤本和蕨类功能群的相对多度也出现增加趋势,但禾本科草本功能群显著减少(P0.05);木本、藤本和蕨类功能群的相对盖度也呈现增加趋势,但禾本科草本功能群与对照组相比显著减少(P0.05);主成分分析(PCA)发现萌芽更新或植苗更新林的林下植物功能群组成和分布与对照组相比均发生了显著的变异,但不同更新方式(萌芽和植苗)下其林下植物功能群组成和分布差异不明显;通过冗余分析(RDA)确定了冠层透光系数、土壤孔隙度、坡向和土壤氮磷比是影响该林地林下植物功能群的主要因子,它们的叠加效应能解释大于75%的林下植物功能群的变异,最终模型通过排序得到冠层透光系数是影响该林地林下植物功能群的最主要因子。短期的研究发现萌芽和植苗这两种不同的更新方式对桉树林下植物功能群的影响有限,这可能与这两种更新方式形成的林冠结构和土壤理化性质差异性较小有关。     

Individual Canopy‐tree Species Effects on Their Immediate Understory Microsite and Sapling Community Dynamics

Canopy trees are largely responsible for the environmental heterogeneity in the understory of tropical and subtropical species‐rich forests, which in turn may influence sapling community dynamics. We tested the effect of the specific identity of four cloud forest canopy trees on total solar radiation, canopy openness, soil moisture, litter depth, and soil temperature, as well as on the structure and dynamics of the sapling community growing beneath their canopies. We observed significant effects of the specific identity of canopy trees on most understory microenvironmental variables. Soil moisture was higher and canopy openness lower beneath Cornus disciflora. In turn, canopy openness and total solar radiation were higher beneath Oreopanax xalapensis, while the lowest soil moisture occurred beneath Quercus laurina. Moreover, Chiranthodendron pentadactylon was the only species having a positive effect on litter depth under its canopy. In spite of these between‐species environmental differences, only C. pentadactylon had significant, negative effects on sapling density and species richness, which may be associated to low seed germination and seedling establishment due to an increased litter depth in its vicinity. The relevance of the specific identity of canopy trees for natural regeneration processes and species richness maintenance depends on its potential to differentially affect sapling dynamics through species‐specific modifications of microenvironmental conditions.     

Cultivation of Non‐timber Forest Products Alters Understory Light Availability in a Humid Tropical Forest in Mexico1

The planting of non‐timber forest products (NTFPs) in the understory of tropical forests is promoted in many regions as a strategy to conserve forested lands and meet the economic needs of rural communities. While the forest canopy is left intact in most understory plantations, much of the midstory and understory vegetation is removed in order to increase light availability for cultivated species. We assessed the extent to which the removal of vegetation in understory plantations of Chamaedorea hooperiana Hodel (Arecaceae) alters understory light conditions. We also examined how any changes in light availability may be reflected by changes in the composition of canopy tree seedlings regenerating in understory plantations. We employed a blocked design consisting of four C. hooperiana plantation sites; each site was paired with an adjacent, unmanaged forest site. Hemispherical canopy photographs were taken and canopy tree seedlings were identified and measured within 12 3 × 2 m randomly placed plots in each site for a total of 96 plots (4 blocks × 2 sites × 12 plots). Plantation management did not affect canopy openness or direct light availability but understory plantations had a higher frequency of plots with greater total and diffuse light availability than unmanaged forest. Comparisons of canopy tree seedling composition between understory plantations and unmanaged forest sites were less conclusive but suggest that management practices have the potential to increase the proportion of shade‐intolerant species of tree seedlings establishing in plantations. Given the importance of advanced regeneration in gap‐phase forest dynamics, these changes may have implications for future patterns of succession in the areas of forest where NTFPs are cultivated.     

Community structures of Mesostigmata, Prostigmata and Oribatida in broad-leaved regeneration forests and conifer plantations of various ages

The community structures of Mesostigmata, Prostigmata, and Oribatida in the soil of broad-leaved regeneration forests and conifer plantations of various ages were assessed alongside soil and plant environmental variables using three response metrics (density, species richness, and species–abundance distribution). The density and species richness of mites recovered swiftly after clear-cutting or replanting. Oribatid mites dominated the soil mite communities in terms of densities and species richness for both forest types. Soil mite communities in broad-leaved forests was related to forest age, the crown tree communities index, and forest-floor litter weight. In contrast, soil mite communities in the conifer plantation sites were related to various indices of understory plants. The development of the understory plants was synchronized with the silvicultural schedules, including a closed canopy and thinning. Such a conifer plantation management may affect indirectly the community of mites.     

Rain forest composition and patterns of secondary succession in the Vava'u Island Group,Tonga

Abstract. The Vava'u island group, Tonga, comprises ca. 60 limestone islands on a single submarine platform overlain with rich soils derived from tephra deposits from nearby volcanic islands. The island group has moderate topographic relief (215 m) and is characterized by plateaus and steep cliffs. Humans settled in Tonga ca. 3000 yr ago and have exploited the flatter terrain for agriculture since that time. We conducted the first survey of forest composition in Vava'u, sampling remnant patches of late-successional forest as well as stands in various stages of secondary succession following agricultural abandonment. Plant species composition did not vary greatly with elevation over this short gradient, in contrast with patterns found on‘Eua, a higher island in Tonga. The most significant environmental gradient affecting species composition was coastal or maritime influence. However, the greatest variation in species composition and structure appeared to be related to species turnover during secondary succession, and we hypothesize a sequence of species replacements. Secondary forest begins to resemble late-successional forest in 30–50 yr in terms of structure and native species richness and therefore is of significant conservation value.     

Light heterogeneity affects understory plant species richness in temperate forests supporting the heterogeneity–diversity hypothesis

One of the most important drivers for the coexistence of plant species is the resource heterogeneity of a certain environment, and several studies in different ecosystems have supported this resource heterogeneity–diversity hypothesis. However, to date, only a few studies have measured heterogeneity of light and soil resources below forest canopies to investigate their influence on understory plant species richness. Here, we aim to determine (1) the influence of forest stand structural complexity on the heterogeneity of light and soil resources below the forest canopy and (2) whether heterogeneity of resources increases understory plant species richness. Measures of stand structural complexity were obtained through inventories and remote sensing techniques in 135 1‐ha study plots of temperate forests, established along a gradient of forest structural complexity. We measured light intensity and soil chemical properties on six 25 m² subplots on each of these 135 plots and surveyed understory vegetation. We calculated the coefficient of variation of light and soil parameters to obtain measures of resource heterogeneity and determined understory plant species richness at plot level. Spatial heterogeneity of light and of soil pH increased with higher stand structural complexity, although heterogeneity of soil pH did not increase in conditions of generally high levels of light availability. Increasing light heterogeneity was also associated with increasing understory plant species richness. However, light heterogeneity had no such effects in conditions where soil resource heterogeneity (variation in soil C:N ratios) was low. Our results support the resource heterogeneity–diversity hypothesis for temperate forest understory at the stand scale. Our results also highlight the importance of interaction effects between the heterogeneity of both light and soil resources in determining plant species richness.     

Primary plant successions of forest belt vegetation on the Tolbachinskii Dol volcanic plateau (Kamchatka)

Primary plant successions on volcanic deposits of the Tolbachinskii Dol Plateau (Central Kamchatka) were studied. The main factors determining the succession rate were revealed. The peculiarities of plant successions on lava flows and ash–scoria deposits differed significantly. Some common mechanisms for all volcanic regions of the world were revealed. The leading factors of plant succession on lava flows were the type of lava surface, the texture of lava, and the fine tephra accumulation rate. The main factors determining plant succession on ash–scoria deposits were wind and water erosion and the distance to the seed sources. The time of formation of a secondary permanent larch (Larix cajanderi Mayr.) forest should take about 1500–2000 years on lava flows and up to 1000 years (but not less than 300–500 years) on ash–scoria plains.     

Influence of light and soil moisture on Sierran mixed-conifer understory communities

Sierra Nevada forests have high understory species richness yet we do not know which site factors influence herb and shrub distribution or abundance. We examined the understory of an old-growth mixed-conifer Sierran forest and its distribution in relation to microsite conditions. The forest has high species richness (98 species sampled), most of which are herbs with sparse cover and relatively equal abundance. Shrub cover is highly concentrated in discrete patches. Using overstory tree cover and microsite environmental conditions, four habitats were identified; tree cluster, partial canopy, gap, and rock/shallow soil. Herb and shrub species were strongly linked with habitats. Soil moisture, litter depth and diffuse light were the most significant environmental gradients influencing understory plant distribution. Herb cover was most strongly influenced by soil moisture. Shrub cover is associated with more diffuse light, less direct light, and sites with lower soil moisture. Herb richness is most affected by conditions which influence soil moisture. Richness is positively correlated with litter depth, and negatively correlated with direct light and shrub cover. Disturbance or management practices which change forest floor conditions, shallow soil moisture and direct light are likely to have the strongest effect on Sierran understory abundance and richness.     

Importance of the understory stratum to entomofaunal diversity in a temperate deciduous forest

The vertical stratification of lepidopteran and coleopteran communities in a cool-temperate deciduous forest in Japan was examined to evaluate the hypothesis of an expected uniform distribution of mobile flying insects between the canopy and understory of temperate forests. Lepidopteran and coleopteran insects were trapped using light traps at three sites in each of the canopy and understory for three consecutive nights each month from April to October 2001. For Lepidoptera, species richness, abundance, and family richness were significantly higher in the understory than in the canopy. For Coleoptera, only abundance was larger in the canopy relative to the understory; species and family richness did not differ between the strata. The beta diversity of the lepidopteran community was larger between the strata than among sites, but the coleopteran community showed an inverse pattern. These results imply the presence of vertical stratification within the lepidopteran community, but not within the coleopteran community, in the temperate forest. The understory contributes more than the canopy to lepidopteran diversity in the temperate forest, although this stratification may be relatively weak because, in contrast to the situation in tropical forests, the canopy and understory assemblages share many species.     

Late-glacial and Holocene vegetation history of the Magellanic rain forest in southwestern Patagonia,Chile

A ¹⁴C-dated high-resolution palaeoenvironmental record from a mire in southern Chile is used to reconstruct the Late-glacial and Holocene vegetation history of the Magellanic rain forest. The Late-glacial environment after around 15400–13500 cal b.p. was dominated by Gunnera magellanica, Nothofagus species (dombeyi type) and Gramineae (Poaceae) indicating an open parkland with cool and damp climatic conditions. At the end of the Late-glacial there was an increase in G. magellanica and a decline in Nothofagus dombeyi type. This ecological signal is interpreted as a result of a re-advance of the Gran Campo Nevado icefield, caused by either Younger Dryas cooling or a latitudinal shift of the southern Westerlies. After around 11250–10750 cal b.p. Nothofagus species, Drimys winteri and Embothrium coccineum expanded, indicating development of the Magellanic rain forest. At 4254±120 cal b.p. a tephra layer was deposited by the eruption of the Mt. Burney volcano leading to a long-term decline of the Nothofagus forest. A primary succession was then initiated, lasting for over 800 years before pre-eruption vegetation patterns redeveloped. In summary, our results indicate the extreme sensitivity of the Magellanic rain forest to climatic or volcanic impacts and the slow recovery of a mature forest after environmental changes.     

Canonical correspondence analysis of early volcanic succession on Mt Usu,Japan

Canonical correspondece analysis (CCA) was applied to explore revegetation patterns during early succession on Mt Usu. Vegetation was buried by deposits of ash and pumice from 1 to 3 m in depth from the 1977–78 eruptions. Three habitats were selected: tephra, tephra in gully and original surface. Plant density and plant cover data were analyzed separately. Environmental factors consisted of five quanticative variables (organic matter, elevation, distance from colonizing source, erosion and deposition of volcanic deposits) and three nominal variables (habitat types: tephra, tephra in gully and original surface). Canonical correspondence analysis showed that the original surface played a special role in vegetation development because the old topsoil supplied both nutrients and seed-bank species. The CCA also suggested that the environmental factors that influence plant density and cover differ. Distance from colonizing source affected plant density while erosion affected cover. Using CCA, factors could be distinguished that influenced seedling establishment from vegetation expansion and vegetation recovery dynamics could also be more clearly interpreted.