Colonization and early succession on anthropogenic soils

Abstract. This paper reports on vegetation development on permanent experimental plots during five years of succession. Nine (1 m²) plots were filled with three typical substrates from man-made habitats of urban and industrial areas in the region of Berlin. The three substrates (a commercial ‘topsoil’, a ruderal ‘landfill’ soil and a sandy soil), differ in organic matter and nutrient contents. Relevés of species composition and percent cover of each species present were made monthly during the growing season from the start of vegetation development. This paper describes the different successional pathways on topsoil and ruderal soil and the colonization process on sandy soil. On topsoil, ruderal annuals are dominant in the first year and are replaced by short-lived perennials from the second year. Those species were replaced by long-lived perennial herbs (Ballota nigra or Urtica dioica) from the third year of succession onwards. On the ruderal land-fill soil the early successional stages are less sharp and the perennial Solidago canadensis is able to dominate within one year after the succession was initiated. On sandy soil there is still an ongoing colonization process, where pioneer tree species like Betula pendula and Populus nigra play a main role. The importance of ‘initial floristic composition’, the role of substrate for community structure and the peculiarities of successional sequences on anthropogenic soils in the context of primary and secondary successions are discussed.     

Vegetation succession on reclaimed coal wastes in Spain: the influence of soil and environmental factors

Question: How is vegetation succession on coal mine wastes under a Mediterranean climate affected by the restoration method used (topsoil addition or not)? How are plant successional processes influenced by local landscape and soil factors? Location: Reclaimed coal mines in the north of Palencia province, northern Spain (42°47′‐42°50′ N, 4°32′‐4°53′ W). Methods: In Jun–Jul 2008, vascular plant species cover was monitored in 31 coal mines. The mines, which had been restored using two restoration methods (topsoil addition or not), comprised a chronosequence of different ages from 1 to 40 yr since restoration started. Soil and environmental factors at each mine were monitored and related to species cover using a combination of ordination methods and Huisman–Olff–Fresco modeling. Results: Plant succession was affected by restoration method . Where topsoil was added, succession was influenced by age since restoration and soil pH. Where no topsoil was added, soil factors seem to arrest succession. Vegetation composition on topsoiled sites showed a gradient with age, from the youngest, with early colonizing species, to oldest, with an increase in woody species. Vegetation on non‐topsoiled sites comprised mainly early‐successional species. Response to age and pH of 37 species found on topsoiled mines is described. Conclusions: Restoration of coal mines under this Mediterranean climate can be relatively fast if topsoil is added, with a native shrub community developing after 15 yr. However, if topsoil is not used, it takes more than 40 yr. For topsoiled mines, the species found in the different successional stages were identified, and their tolerance to soil pH was derived. This information will assist future restoration projects in the area.     

采石场废弃地的生态重建研究进展

采石场的开采严重破坏了植被和土壤,形成了大量的裸露岩石斜坡,造成宏观景观支离破碎和极端的环境条件,限制了植物的生长。由于自然恢复所需时间长久,人工恢复被广泛应用于采石场废弃地的生态重建。自然演替过程是采石场生态重建的理论基础,自然演替理论可以为人工恢复措施提供指导。植物群落演替的早期阶段,非生物因素起主要作用,随着演替的推移,生物因素的重要性增强。邻近自然植被的土壤和繁殖体通过外力的扩散,对恢复起重要作用。除了非生物和其他的限制,先到达恢复地的物种竞争能力的变化能决定了演替过程。演替过程中的干扰因素往往成为演替重要的驱动力。裸露岩石斜坡的物理稳定性对植被恢复有重要影响,有机废物的使用和施肥可以影响恢复演替的方向和生物多样性。播种一定的植物能够改变恢复演替方向,加速演替过程。乡土物种适应了当地气候,能够促进演替。随着修复时间的延长,土壤有机质含量,植被覆盖度和物种丰富度不断增加,土壤微生物生物量随之增加。开展不同地区采石场植物种类的选育、研究乡土物种的功能特性、土壤微生物群落和酶的变化、植被演替过程的定位研究、植物种间的竞争关系、自然演替和人工恢复的比较研究、探索经济高效的采石场生态重建方法是未来的研究方向。     

三江平原恢复湿地土壤种子库特征及其与植被的关系

通过幼苗萌发法和样方调查相结合的方法对三江平原不同演替恢复阶段的种子库特征及其与植被的关系进行了研究。将开垦湿地、不同演替恢复阶段湿地以及天然湿地不同土壤层次(0-5、5-10 cm和根茎)的种子库在两种水分条件下(湿润、淹水10 cm)进行萌发处理。结果表明: 随着演替恢复阶段的进行, 种子库的结构和规模逐渐扩大, 地表群落表现出由旱生物种占优势的群落逐渐演变成以小叶章(Calamagrostis angustifolia)占优势的湿生群落的演替趋势。恢复7年湿地、恢复14年湿地、天然湿地土壤种子库萌发物种数分别为24种、29种、39种, 植被物种数为21种、25种、14种。湿地类型、水分条件和土壤层次均显著影响种子库萌发的物种数及幼苗数(p < 0.01)。种子库具有明显的分层现象, 天然湿地0-5 cm土层种子库种子萌发密度是5-10 cm土层的4倍左右, 而恢复湿地仅1.3倍左右, 且土层间萌发物种相似性系数较低。湿润条件下的萌发物种数显著高于淹水条件, 且两种水分条件下萌发物种的生活型不同。由于恢复时间较短, 不同演替恢复阶段的种子库与植被相似性维持在30%以下。湿地中根茎分蘖出大量的湿地物种, 对于小叶章等优势物种的繁殖具有重要作用。研究表明, 在开垦湿地退耕后的次生演替阶段, 种子库能够保持大量的湿地物种, 通过对湿地种子库与植被的关系研究, 能够为三江平原湿地群落演替与湿地恢复提供策略指导。     

The relationship between soil seed bank,above‐ground vegetation and disturbance intensity on old‐field successional permanent plots

Questions: How does disturbance and successional age influence richness, size and composition of the soil seed bank? What is the potential contribution of the soil seed bank to the plant community composition on sites differing in their successional age or disturbance intensity? Location: Experimental Botanical Garden of Göttingen University, central Germany. Methods: Above‐ground vegetation and soil seed bank were studied on formerly arable fields in a 36‐year‐old permanent plot study with five disturbance intensities, ranging from yearly ploughing via mowing to long‐term uninterrupted succession. We compared species compositions, seed densities and functional features of the seed bank and above‐ground vegetation by using several methods in parallel. Results: The seed bank was mainly composed of early successional species typical of strongly disturbed habitats. The difference between seed bank composition and above‐ground vegetation decreased with increasing disturbance intensity. The species of greatest quantitative importance in the seed bank was the non‐native forb Solidago canadensis. Conclusions: The ability of a plant community to regenerate from the soil seed bank dramatically decreases with increasing time since abandonment (successional age) and with decreasing disturbance intensity. The present study underlines that plant species typical of grasslands and woodlands are limited by dispersal capacity, owing to low capacity for accumulation of seeds in the soil and the fact that most species do not build up persistent seed banks. Rare and target species were almost absent from the seed bank and will, after local elimination, depend on reintroduction for continuation of their presence.     

Rate of succession in restored wetlands and the role of site context

Question: Are changes in plant species composition, functional group composition and rates of species turnover consistent among early successional wetlands, and what is the role of landscape context in determining the rate of succession? Location: Twenty‐four restored wetlands in Illinois, USA. Methods: We use 4 years of vegetation sampling data from each site to describe successional trends and rates of species turnover in wetlands. We quantify: (1) the rate at which composition changes from early‐successional to late‐successional species and functional groups, as indicated by site movement in ordination space over time, and (2) the rate of change in the colonization and local extinction of individual species. We correlate the pace of succession to site area, isolation and surrounding land cover. Results: Some commonalities in successional trends were evident among sites. Annual species were replaced by clonal perennials, and colonization rates declined over time. However, differences among sites outweighed site age in determining species composition, and the pace of succession was influenced by a site's landscape setting. Rates of species turnover were higher in smaller wetlands. In addition, wetlands in agricultural landscapes underwent succession more rapidly, as indicated by a rapid increase in dominance by late‐successional plants. Conclusions: Although the outcome of plant community succession in restored wetlands was somewhat predictable, species composition and the pace of succession varied among sites. The ability of restoration practitioners to accelerate succession through active manipulation may be contingent upon landscape context.     

热带森林不同演替阶段蚂蚁巢穴的分布特征及其影响因素

为探明热带森林蚂蚁巢穴的分布特征及其影响因素, 采用样方法研究了西双版纳不同演替阶段热带森林定居巢穴蚂蚁的种类及其巢穴的密度、盖度和空间分布特征, 并分析了土壤理化环境与蚂蚁种类总数、巢穴密度及盖度的相关性。结果表明, 不同演替阶段热带森林蚂蚁种类总数、巢穴的密度及盖度大小顺序为: 小果野芭蕉 (Musa acuminata)群落>白背桐(Mallotus paniculatus)群落>思茅崖豆(Mellettia leptobotrya)群落, 并且热带森林的演替类型显著影响蚂蚁种类总数及巢穴密度, 而对巢穴盖度的影响未达到显著水平; 蚂蚁种类总数、巢穴密度与土壤总有机碳和水解氮显著正相关, 与土壤容重和土壤含水率显著负相关, 但所选择的土壤理化指标与巢穴盖度的相关性均未达到显著水平; 蚂蚁巢穴的空间分布呈随机分布格局。我们的数据表明, 不同演替阶段热带森林所形成的植被类型及土壤环境状况共同影响定居的蚂蚁种类总数与筑巢密度。     

Static and dynamic approaches to landscape heterogeneity in the Hungarian forest‐steppe zone

Abstract. This paper describes the successional status of the vegetation in a clear‐felled dry oak woodland at the edge of the Hungarian forest‐steppe zone on the basis of a vegetation map. Due to a varied geomorphology of the colline landscape several so‐called landscape units can be distinguished. The patchwork on the vegetation map is evaluated using several, morphology‐based attributes (static morphological indices) traditionally applied in landscape ecology. In the ca. 100 years that elapsed since forest clear‐cut, xeric grassland species and steppe elements became more abundant and the former xeromesophilous vegetation – containing even some woodland components – is slowly turning into xeric grassland communities. The vegetation units mapped can be arranged into a hypothetical succession scheme in which successional distances (the number of steps between two stages) are determined. Based on the distances thus obtained, a new dynamic morphological index is introduced. This is applied to each landscape unit for the dynamic evaluation of successional vegetation, its results being compared with those obtained by static morphological indices.     

Seed bank assembly follows vegetation succession in dune slacks

Question: Is the seed bank in dune slacks during the whole successional range mainly composed of early successional species or does it vary according to the changing vegetation? Location: Belgium, western part of the coast. Methods: We investigated the soil seed bank composition using a seedling germination method in a chronosequence of 20 dune slacks, ranging in age from five to 55 yr. Results: Both seed density and species richness in the seed bank were very low in the first successional stages and increased with age, mainly as a result of increasing seed production. The similarity between seed bank and vegetation was higher in older slacks. A comparison of characteristics between seed bank and vegetation showed that the seed bank was, to a large extent, composed of later successional species. Occurrence patterns of individual species also showed that seeds become incorporated in the soil after the species has established in the vegetation. Conclusion: The seed bank is not likely to be the driving force for successional changes in the vegetation, and successional changes rely on dispersal. Some early successional species persist in the seed bank, but generally only in low numbers. The results also confirm that most typical dune slack species do not form persistent seeds, so that re‐establishment from the seed bank is not to be expected when the species has disappeared from the vegetation.     

Soil physicochemical properties drive the variation in soil microbial communities along a forest successional series in a degraded wetland in northeastern China

The Sanjiang Plain is the biggest freshwater wetland locating in northeastern China. Due to climate change and human activities, that wetland has degraded to a successional gradient from the original flooded wetland to dry shrub vegetation and a forest area with lower ground water level, which may result in changes in soil microbiologic structure and functions. The present study investigated the microbial diversity and community structure in relation to soil properties along that successional gradient. The soil physico‐chemical properties changed significantly with degradation stage. The Shannon diversity index of both soil bacteria (5.90–6.42) and fungi (1.7–4.19) varied significantly with successional stage (both p < .05). The community structures of soil bacteria and fungi in the early successional stages (i.e., the wetland) were significantly determined by water content, total nitrogen, and available nitrogen concentrations in soils, while those in the later successional stages (i.e., forests) were significantly structured by soil organic carbon, soil pH, and available phosphorus concentrations. These results suggest that the soil microbial structure is mainly determined by soil properties rather than by plant community such as plant species composition along successional stages.     

Successional dynamics of the bee community in a tropical dry forest: Insights from taxonomy and functional ecology

Despite the recent rapid growth of tropical dry forest succession ecology, most studies on this topic have focused on plant community attribute recovery, whereas animal community successional dynamics has been largely overlooked, and the few existing studies have used taxonomic approaches. Here, we analyze the successional changes in the bee community in a Mexican tropical dry forest, by integrating taxonomic (species, genus, and family diversity) and functional (sociability, nesting strategy, and body size) information for bees. Over one year, in a successional chronosequence (2–67 years after abandonment) we collected 469 individual bees, representing five families, 36 genera, and 69 species. Linear modeling showed decreases in taxonomic diversity with succession, more strongly so for species. Bee species turnover along succession ranged from moderate to high, decreasing slightly at intermediate stages. An RLQ analysis (ordination method that allows relating environmental variables with functional attributes) revealed clear relations between bee functional traits and the plant community. RLQ axis 1 was positively related to vegetation structural and diversity variables, and to eusociality, while solitary, parasociality, and ground nesting was negatively associated with it. Early successional fallows attract mostly solitary and parasocial bees; older fallows tend to attract eusocial bees with aerial nesting. The continuous taxonomic turnover observed by us and the functional analysis suggest that the disappearance of old fallows from agricultural landscapes would likely result in significant reductions and even local extinctions of particular bee guilds. Considering the low viability of preserving large mature tropical dry forest tracts, the conservation of older successional stands emerges as a crucial component of landscape management.Abstract in Spanish is available with online material.     

Primary forest succession on poor sandy soilsas related to site factors

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.     

云南松林次生演替阶段土壤细菌群落的变化

土壤细菌多样性是维持森林生态系统功能的关键因子,森林演替是影响其动态变化的重要因素.研究云南松林不同演替阶段土壤细菌群落结构及其多样性的变化规律,有助于深入理解森林生态系统恢复过程的驱动机制.本研究以云南省永仁县皆伐后形成的针叶林、针阔混交林和常绿阔叶林为对象,基于Illumina Hiseq高通量测序技术,分析森林演...     

贵州省普定县不同植被演替阶段的物种组成与群落结构特征

通过对贵州省普定县喀斯特地区不同植被演替阶段群落的调查, 研究了植被演替过程中群落物种组成和群落结构的变化。结果表明, 该地区的植被主要处于5个演替阶段, 即次生乔木林、乔灌过渡林、藤刺灌丛、稀灌草丛以及火烧干扰后的蕨类植物群落。本次调查共记录到植物365种, 隶属89科218属。其中, 蕨类植物31种, 隶属14科23属; 种子植物334种, 隶属75科195属。物种分布较多的科主要有蔷薇科、菊科、禾本科、百合科、忍冬科、唇形科、莎草科、樟科、葡萄科和水龙骨科。随着正向演替的推进, 物种丰富度增加, 群落结构趋于复杂化。藤刺灌丛与乔灌过渡林群落层次不明显, 次生乔木林分层明显。从藤刺灌丛向次生乔木林演替的过程中, 小径级个体所占比例明显降低, 高于1.3 m植物的总密度、乔木密度和藤本密度都先升高后降低, 而灌木密度呈逐渐降低的趋势。对喀斯特地区植被的恢复提出了参考措施。     

中国西南喀斯特植物群落演替特征及驱动机制

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。     

Temporal variation in plant-soil feedback controls succession

Soil abiotic and biotic factors play key roles in plant community dynamics. However, little is known about how soil biota influence vegetation changes over time. Here, we show that the effects of soil organisms may depend on both the successional development of ecosystems and on the successional position of the plants involved. In model systems of plants and soils from different successional stages, we observed negative plant–soil feedback for early-successional plant species, neutral feedback for mid-successional species, and positive feedback for late-successional species. The negative feedback of early-successional plants was independent of soil origin, while late-successional plants performed best in late- and worst in early-successional soil. Increased performance of the subordinate, late-successional plants resulted in enhanced plant community diversity. Observed feedback effects were more related to soil biota than to abiotic conditions. Our results show that temporal variations in plant–soil interactions profoundly contribute to plant community assemblage and ecosystem development.     

Avian taxonomic and functional diversity in early stage of longleaf pine (Pinus palustris) stands restored at agricultural lands: variations in scale dependency

In agricultural landscapes, the longleaf pine initiative (LLPI) and the Bobwhite Quail Initiative (BQI) aim to restore longleaf pine forests and early successional habitats, respectively. The early stage of longleaf pine stands and grass and forb vegetation produced by a combination of both restoration programs (LLPI‐BQI) may form habitat conditions favorable to early successional bird species and other birds, increasing avian diversity. We investigated how the LLPI and BQI programs affected taxonomic and functional diversity of birds and abundance of early successional birds (grassland and scrub/shrub species), and what environmental characteristics were associated with the diversity and abundance of birds. Our study was performed at 41 fields in Georgia, United States, during 2001–2002 by considering environmental characteristics at two spatial scales: local‐scale vegetation features and restoration program type (LLPI or LLPI‐BQI) and landscape‐scale vegetation features and landscape heterogeneity. Functional evenness, species richness, and abundance of grassland and scrub/shrub species did not show a clear association with local‐ or landscape‐scale variables. Shannon‐Wiener diversity was slightly influenced by restoration program type (local‐scale variable) with higher value at LLPI‐BQI stands than at LLPI stands despite no significant differences in local vegetation features between those stands. Functional divergence was strongly positively associated with landscape‐scale variables. That is, niche differentiation increased with increasing shrub coverage within a landscape, reducing competition between abundant bird species and others. Our results suggest that although a combination of BQI and LLPI program may have a positive effect on avian taxonomic diversity, it is important to consider shrub vegetation cover within a landscape to improve functional diversity.     

Secondary Succession and Natural Habitat Restoration in Abandoned Rice Fields of Central Korea

Floristic composition and soil characteristics (moisture, pH, nutrient contents) in abandoned upland rice paddies of different ages were analyzed to clarify the regenerative aspects of succession as a tool for habitat restoration. The study sites represented five seral stages: newly abandoned paddy fields; successional paddy fields abandoned for 3, 7, and 10 years; and a 50‐year‐old Alnus japonica forest. A vegetation sere was apparent in changes of dominant plant species in the order Alopecurus aequalis var. amurensis (annual grass), Aneilema keisak (annual forb), Juncus effusus var. decipiens (rush), Salix koriyanagi (willow), and Alnus japonica (alder) communities. These temporal stages resemble the spatial zonation of vegetation in local riparian floodplain ecosystems, indicating a hydrosere, with soil moisture decreasing over time. Age distributions and life forms of the dominant plant species support a “tolerance” model of secondary succession, in which the established species persist into later successional stages. Persistence of earlier colonizers led to a net cumulative increase in species richness and a more even distribution of species cover with increasing field age. Between 10 and 50 years, vegetation stabilizes as an alder community. Soil moisture content decreased steadily with paddy field age after an initial rise immediately after their abandonment, whereas pools of organic matter, N, P, K, Ca, and Mg, increased with field age. The pace and direction of recovery of native vegetation and natural soil properties in these abandoned rice paddies resembled classic old field succession, a form of secondary succession that often serves as a template for guiding restoration efforts. Active intervention, in particular dismantling artificial levees, could accelerate the recovery process, but natural habitat recovery generally appears sufficiently robust to achieve “passive” restoration of this rare community without intervention.     

Local and landscape factors determining occurrence of phyllostomid bats in tropical secondary forests

Neotropical forests are being increasingly replaced by a mosaic of patches of different successional stages, agricultural fields and pasture lands. Consequently, the identification of factors shaping the performance of taxa in anthropogenic landscapes is gaining importance, especially for taxa playing critical roles in ecosystem functioning. As phyllostomid bats provide important ecological services through seed dispersal, pollination and control of animal populations, in this study we assessed the relationships between phyllostomid occurrence and the variation in local and landscape level habitat attributes caused by disturbance. We mist-netted phyllostomids in 12 sites representing 4 successional stages of a tropical dry forest (initial, early, intermediate and late). We also quantitatively characterized the habitat attributes at the local (vegetation structure complexity) and the landscape level (forest cover, area and diversity of patches). Two focal scales were considered for landscape characterization: 500 and 1000 m. During 142 sampling nights, we captured 606 individuals representing 15 species and 4 broad guilds. Variation in phyllostomid assemblages, ensembles and populations was associated with variation in local and landscape habitat attributes, and this association was scale-dependent. Specifically, we found a marked guild-specific response, where the abundance of nectarivores tended to be negatively associated with the mean area of dry forest patches, while the abundance of frugivores was positively associated with the percentage of riparian forest. These results are explained by the prevalence of chiropterophilic species in the dry forest and of chiropterochorous species in the riparian forest. Our results indicate that different vegetation classes, as well as a multi-spatial scale approach must be considered for evaluating bat response to variation in landscape attributes. Moreover, for the long-term conservation of phyllostomids in anthropogenic landscapes, we must realize that the management of the habitat at the landscape level is as important as the conservation of particular forest fragments.     

Soil seed bank dynamics in alpine wetland succession on the Tibetan Plateau

The primary goal was to address several questions with regard to how soil seed banks change in a successional series. How does the composition of the viable seed bank change, and how does the relationship of the soil seed bank and vegetation change with succession? Can the seed bank be regarded as a potential as a source of seeds for wetland restoration? We collected soil seed bank samples and sampled the vegetation in four different successional stages and used the NMDS (nonmetric multidimensional scaling) to evaluate the relationship of species composition between the seed banks and vegetation. The difference of seed density and species richness in different habitats and soil depths also was compared. Viable seeds of half (37) the species in the early-successional stage were found in all the successional stages. Similarity between seed bank and vegetation increased with succession. Both seed density and species richness in the seed bank increased with successional age and decreased with soil depth. The majority of species from the early-successional stage produced long-lived seeds. Seed density and species richness increased with succession, mainly as a result of increasing seed production, and hypotheses predicting decreasing density of buried seeds and species richness were not confirmed. Seed banks play a minor role in contributing to the regeneration of vegetation, and managers cannot rely on soil-stored seed banks for restoration of wetlands.