Spontaneous Succession Research Articles

From arable land to species-rich semi-natural grasslands: Succession in abandoned fields in a dry region of central Europe

The area of arable land has decreased considerably in Europe over the last decades. Abandoned fields are potential habitats for restoration of species-rich grasslands of high conservation value, but in specific cases it is unclear whether this can be achieved by spontaneous succession or intervention is needed. In dry areas of eastern-central Europe, spontaneous succession of species-rich steppe grasslands was observed on some abandoned fields located close to ancient grasslands. We studied spontaneous succession on ex-arable land in the warm and dry area of the SE Czech Republic using space-for-time substitution. Vegetation was sampled in 175 plots, for which the time since the abandonment (4–71 years) was determined from historical aerial photographs. All plots were close to ancient dry grasslands. Annual weeds were replaced by perennial species in less than four years after abandonment. Perennial grassland was stable over seven decades, but its species composition changed: native dry-grassland species, including Red-List species, gradually increased, and so did the total number of vascular plants, reaching on average of 30–40 species per 16m2 after 40 years. Archaeophytes, including common ruderal species, decreased, while neophytes were insignificant throughout the succession. Scattered shrubs appeared at later stages, but their spread was limited by drought and recently also by nature conservation management. This study suggests that spontaneous succession can be inexpensive yet effective means of dry grassland restoration in dry areas of eastern and central Europe if sources of target species are available in nearby remnants of ancient grasslands.

PLONY I CHEMIZM ROŚLIN WIELOWARIANTOWEGO DOŚWIADCZENIA NA MODELOWYM ZŁOŻU ODPADÓW PALENISKOWYCH ENERGETYKI WĘGLOWEJ. CZĘŚĆ II (LATA 2012 – 2013)

Reclamation efficiency of composts produced from the mixture of municipal waste (Radiowo and ZUSOK), urban green waste composts (Complex), housing estate lawn mowing waste (plants) and sewage sludge, as well as mineral fertilizer (NPK – without the use of any organic fertilizer), was assessed in a model experiment on an ash soil. The experiment was launched in 2005 and continued until the end of 2013. Crops were collected and subjected to the analysis in 2005, 2006 and between 2011 and 2012. In the period between 2007 and 2010 no agrotechnical treatments were carried out, with the experiment being limited to mere observation of the natural (spontaneous) succession of plants. Reclamation doses of composts and sewage sludge were measured quantitatively, therefore they differed in the content of dry matter as well as in the contents of organic substances and minerals in the dry matter. The largest aggregated dry matter yield of plants (2005–2013) was reported in the Complex variant, and similarly, in the Radiowo and plant variants, whereas the ZUSOK variant reported the lowest aggregated dry matter field of plants. The yield-forming efficiency of NPK fertilizer was lower than in the case of compost and sludge variants. However, the field-forming efficiency of sewage sludge was lower than its fertilization potential as it was unstable and difficult to mix with the experimental soil. The results showed the yield-forming potential of plants on the experimental coal combustion waste deposits fertilized with composts and sewage sludge as well as the examples of the sites where sewage sludge could be used for the biological reclamation of landfills and spoil tips.

Landscape context in colonization of restored dry grasslands by target species

AbstractQuestionsAlthough the role of landscape context, often interpreted as the available species pool, is generally assumed to be important for the restoration of disturbed sites, not many studies evaluating this role quantitatively in restored dry grasslands have been carried out. There is especially a lack of large‐scale, multi‐site studies. We asked how many unsown target species established spontaneously in restored dry grasslands and how spontaneous establishment depended on their occurrence in the surrounding landscape.LocationWhite Carpathian Mts., eastern Czech Republic (48°50′–49°05′ N, 17°19′–17°55′ E, 250–610 m a.s.l.).MethodsWe studied spontaneous colonization by unsown target species in dry grasslands on ex‐arable land at 82 sites, sown with a regional seed mixture, commercial clover–grass seed mixtures or left to spontaneous succession. In total, 246 phytosociological relevés in 5‐m × 5‐m plots were recorded. Restoration started 1–31 yr ago. Nearby semi‐natural grasslands were included as reference sites (94 phytosociological relevés). A total of 108 target species were defined and their presence evaluated in the surroundings of the restored grasslands, i.e., in grid cells (3.1 km × 2.8 km) in which the restored sites were situated. Data were processed using multivariate analyses (DCA, CCA) and GLM.ResultsThe number of target species at the restored sites significantly increased with time elapsed since restoration started and the number of target species occurring in the surroundings. The sites, although restored in different ways, converged in their species composition towards ancient grasslands. The maximum relative colonization of a restored grassland by target species from the surroundings was 23.4%, and the restored grasslands contained max. Fifty‐seven percent of the average number of dry grassland target species present in the ancient grasslands.ConclusionsSowing seed mixtures should be seen as not more than a first phase in the restoration of species‐rich grasslands. In a next phase of restoration, we can reasonably rely on gradual spontaneous colonization by target species if they occur in the surroundings, even at sites sown with commercial seed mixtures or restoring spontaneously. However, full restoration probably takes decades or more.

Dry sandpits and gravel–sandpits serve as key refuges for endangered epigeic spiders (Araneae) and harvestmen (Opiliones) of Central European steppes aeolian sands

Although the value of the habitat lost by quarrying is widely known, awareness of the conservation value of the newly formed habitat is negligible. We provide evidence on the conservation value of both active and disused sandpits and gravel–sandpits for epigeic spiders and harvestmen, commonly considered important indicator species. We focus on xerothermophilous habitats within sandpits subjected to near-natural succession or other reclamation efforts. We show that xerothermophilous sandpit microhabitats are used by 323.8±23.9 epigeic spider species and 8.5±1.1 harvestmen species, with the species spectrum changing dramatically during spontaneous succession and if the habitat is subject to other forms of reclamation, with low species dominance across all habitats tested. We found 81 spider species recognized as critically endangered, endangered, vulnerable or nearly threatened. Of these, 72 (89%) were present at spontaneously formed xerothermophilous habitats of various ages, and 40 (49%) at the reclaimed sites. We analyzed the species-specific habitat preferences of the red-listed spider species in relation to both abiotic (altitude, slope, soil penetration resistance, soil shear strength resistance, soil texture) and biotic (vegetation cover, plant diversity, diversity of red-listed plants) factors. The xerothermophilous sandpit habitats served as important refuges for Central European steppe and aeolian sand dune species, which had nearly disappeared from the surrounding intensively cultivated cultural landscape.

Post-Fire Changes of Soil Seed Banks in the Early Successional Stage of Pine Forest

ABSTRACT: Our research was conducted on abandoned fields which had been undergoing spontaneous succession for 40–50 years and then were partly burnt. The main objective of the study was to examine if spontaneous fire in the early successional stage of pine forest causes a decrease in the number of species, diversity and density of seed banks, and an increase in the share of species forming long term persistent seed banks. Standing vegetation and soil seed banks were studied on 20 permanent plots on adjacent burnt and unburnt sites one and twelve years after spontaneous fire. One year after the fire the number of species in the seed banks of both areas was similar (11 and 12 species). In the burnt area the Shannon index and the floristical similarity between the seed bank and standing vegetation were lower, and seed density five times higher than in the unburnt area (15 691.5 m-2 vs.3426.5 m-2). This was mainly the effect of the high number of seedlings of Calluna vulgaris (L.) Hull and Spergula morisonii ...

Environmental factors determining spontaneous recovery of industrially mined peat bogs: A multi-site analysis

Peat is still mined in many parts of the World. What to do with the peatlands after the peat mining has stopped is a question for restoration ecologists and to leave a disturbed site to spontaneous regeneration could be one option. The main question of our study was whether it is an effective means of restoration and under which circumstances. Spontaneous succession was studied in 11 industrially mined peatlands, which encompassed successional stages of different age. Vegetation samples (109), 5m×5m in size, were recorded in the stages using visual estimation of percentage cover of all present vascular plants. The age, abiotic environmental characteristics (position of water table, water pH, and substratum chemistry), as well as biotic characteristics (proportion of land cover categories up to 100m, 300m and 1km from each sample, and the distance to the nearest undisturbed peatland vegetation) were assessed for each sampled successional stage. Other characteristics were related to the whole localities (altitude, average annual temperature, and precipitation). The data were analyzed by multivariate statistics. The environmental variables, except K-content and land cover up to 100m, exhibited some significant effects on the vegetation patterns. External, i.e., landscape factors, had together a larger effect on the course of succession than abiotic site factors. The most important particular factors included ground water level, substrate pH, and presence of undisturbed peatland vegetation in the surroundings. Also important was geographic location predominantly reflecting site altitude. Spontaneous recovery of the peatland vegetation was more successful on those sites where the water table was intentionally increased. The increase of the water table after peat extraction and preservation of the original undisturbed peatland vegetation in the area neighbouring a mined site during the process of peat extraction are recommended to promote spontaneous recovery of the peatlands.

Secondary succession in sandy old‐fields: a promising example of spontaneous grassland recovery

AbstractQuestionBased on the spontaneous vegetation development of old‐fields in the Nyírség and Kiskunság sand regions (Hungary), we aimed to answer the following questions using the chronosequence method: (1) how do the proportions of different functional groups change during succession; (2) which target species establish successfully in the old‐fields during the course of succession; and (3) how successful is spontaneous succession in the recovery of target grasslands?LocationTwo sand regions of the Great Hungarian Plain: (1) the Nyírség sand region (East Hungary, acidic sand, moderately continental climate) and the Kiskunság (Central Hungary, calcareous sand, continental climate).MethodsAltogether 24 old‐fields were classified into young (<10‐yr‐old), middle‐aged (10–20‐yr‐old) and late‐succession (20–40‐yr‐old) old‐fields; four fields in each age category. For baseline vegetation reference, three open and three closed sand grassland stands in both regions were sampled in the vicinity of the old‐fields. The percentage cover of vascular plants was recorded in five 2 × 2‐m plots in each field, in early May and late June 2012. We used life forms, clonal spreading traits and Ellenberg indicator values for nutrients in the analysis. Species of Festuco‐Brometea class were considered as target species.ResultsThe cover of hemicryptophytes and geophytes increased, the cover of short‐lived species decreased with time. Cover of species without clonal spreading ability decreased, while cover of species with clonal spreading ability increased with increasing field age. The cover of invasive species decreased with increasing field age. The majority of target species had established already in the young and middle‐aged old‐fields, although their cover was significantly higher in the two older age groups.ConclusionSpontaneous succession can be a vital option in recovery of sand grassland vegetation in Central Europe; the majority of the species pool of sandy grasslands can be recovered in the first 10–20 yrs. However, the success of grassland recovery can be strongly influenced by the surrounding species pool and can be slow if seed dispersal is limited. Spontaneous succession is most promising when the target species of grasslands immigrate at the very beginning of the succession, within the first few years.

How to develop native plant communities in heavily altered ecosystems: examples from large‐scale surface mining in Germany

AbstractQuestionsDoes site alteration caused by mining impede spontaneous colonization of native species assemblies to the advantage of neophytic species at the landscape unit and plant community scale? To what extent can mined site conditions support the establishment of rare plant species assemblies that are locally novel but of regional conservation value? What effects have dispersal limitation and stochasticity on spontaneous succession trajectories and how does community structure and composition differ between actively restored sites and ancient grasslands?LocationCentral German Lignite Mining District.MethodsWe used comprehensive databases to compare floristic composition in mined sites and their surroundings. At the community level, we choose a chronosequence approach to analyse spontaneous colonization of target species into mined sites and the development of calcareous grasslands, compared to ancient as well as actively restored grasslands. Statistical analyses involved Mann–Whitney U‐test, GNMDS and binary logistic regression.ResultsThe proportion of neophytes in spontaneously developing mined sites was low and similar to the unmined surroundings at the landscape unit as well as plant community scale. Mined sites harbour an impressive number of native and even rare species. However, plant communities lacking immigration of target grasses typical for calcareous grasslands lead to divergences regarding species and functional composition compared to ancient calcareous grasslands. In contrast, plots with actively introduced target species at the onset of succession show a generally more rapid trajectory towards ancient grasslands. The probability of establishing in mined sites increases with higher abundance of calcareous dry grassland species in the vicinity, indicating the importance of high propagule pressure in a landscape context, whereas long‐distance dispersal traits were significant, but less important.ConclusionsSpontaneous succession supports the development of native plant communities. However, because of propagule limitation, colonization processes may lead to novel species assemblies. While dispersal stochasticity during spontaneous succession results in a higher γ‐diversity, species introduction supports faster trajectories towards desired reference states providing important ecosystem services such as erosion control. The key decision of whether to rely on spontaneous succession or not mainly depends on the surrounding landscape matrix and history, the need for erosion control and/or rapid compensation for lost habitats.

Restoration of Neotropical grasslands degraded by quarrying using hay transfer

AbstractAimThe campos rupestres are species‐rich tropical mountain grasslands in southeast Brazil that are threatened by mining and quarrying. Eight years following a strong disturbance (i.e. quarrying for gravel exploitation during the asphalting of highway MG‐010), spontaneous succession did not occur on degraded areas. This study was therefore designed to test the restoration technique of hay transfer as a means of enhancing seed dispersal from the reference ecosystems to the degraded areas.LocationCampo rupestre grasslands, Serra do Cipó, Minas Gerais, Brazil.MethodsNine degraded areas representing three kinds of substrate (latosol, sandy and stony) were selected. Hay transfer was carried out using hay collected in two kinds of grassland (i.e. campos arenosos and campos pedregosos) year‐round in 2010, in order to maximize the seed pool. The collected hay was distributed on 40 cm × 40 cm quadrats among the three types of substrate, with and without geotextile, according to the following protocol: hay from campo arenoso grasslands was spread on all types of substrate, while hay from campo pedregoso grasslands was used on stony substrate only.ResultsFew seedlings emerged within 14 mo of the treatment application, despite the large number of seeds contained in the hay, indicating that hay transfer may not be a useful method for restoring degraded areas of campos rupestres. The seedlings emerging on the degraded areas mainly belonged to ruderal species. Therefore, we suggest that, although poor soil conditions could limit seedling establishment, germination issues of the campo rupestre species are the first limitation for restoring degraded campos rupestres using hay transfer.ConclusionOur results highlight the inherent difficulty in restoring degraded areas of campos rupestres; their protection must be made a high conservation priority.

Soil Food Web Changes during Spontaneous Succession at Post Mining Sites: A Possible Ecosystem Engineering Effect on Food Web Organization?

Parameters characterizing the structure of the decomposer food web, biomass of the soil microflora (bacteria and fungi) and soil micro-, meso- and macrofauna were studied at 14 non-reclaimed 1– 41-year-old post-mining sites near the town of Sokolov (Czech Republic). These observations on the decomposer food webs were compared with knowledge of vegetation and soil microstructure development from previous studies. The amount of carbon entering the food web increased with succession age in a similar way as the total amount of C in food web biomass and the number of functional groups in the food web. Connectance did not show any significant changes with succession age, however. In early stages of the succession, the bacterial channel dominated the food web. Later on, in shrub-dominated stands, the fungal channel took over. Even later, in the forest stage, the bacterial channel prevailed again. The best predictor of fungal bacterial ratio is thickness of fermentation layer. We argue that these changes correspond with changes in topsoil microstructure driven by a combination of plant organic matter input and engineering effects of earthworms. In early stages, soil is alkaline, and a discontinuous litter layer on the soil surface promotes bacterial biomass growth, so the bacterial food web channel can dominate. Litter accumulation on the soil surface supports the development of the fungal channel. In older stages, earthworms arrive, mix litter into the mineral soil and form an organo-mineral topsoil, which is beneficial for bacteria and enhances the bacterial food web channel.

Vegetation succession in restoration of disturbed sites in Central Europe: the direction of succession and species richness across 19 seres

AbstractQuestions(1) How do seres differ with respect to vegetation changes? (2) What are the directions of succession? (3) How do species numbers change? (4) How do target species, i.e. those typical of natural and semi‐natural vegetation, participate in succession? (5) Are spontaneously developed successional stages acceptable from the point of view of ecosystem restoration?LocationExtracted peatlands, bulldozed sites in forests destroyed by air pollution, an emerged bottom of a water reservoir, corridors of former Iron Curtain, artificial fishpond islands and barriers, sedimentary basins, spoil heaps from mining, stone quarries, forest clearings, road verges, sand and gravel‐sand pits, ruderal urban sites, river gravel bars and abandoned arable fields, located in various parts of the Czech Republic in Central Europe.MethodsPhytosociological relevés were recorded in 10–25 m2 plots located in the centre of representative successional stages defined by their age, ranging from 1 to 100 yrs. In total, we obtained 2392 vegetation samples containing 951 species. We performed DCA ordination to compare 19 seres. Desirable target species were considered as those representing (semi)‐natural vegetation and all Red List species.ResultsThe seres studied are more similar in their species composition in the initial and early stages, in which synathropic species prevail, than in the later stages when the vegetation differentiates. This divergence is driven mainly by local moisture conditions. In most cases, succession led to woodland, which usually established after ca. 20 yrs. In very dry or wet places (with limited presence of woody species) open vegetation developed, often highly valuable from the restoration and conservation point of view. The total number of species and the number of target species increased in the majority of seres with successional age.ConclusionsThe vegetation in the sites studied formed a continuum along a moisture gradient and by successional age. The individual seres largely overlapped in their species composition; the sere identity was not significant. Spontaneous succession usually proceeded towards woodland, except at very dry or wet sites, and generally appeared to be an ecologically suitable way of ecosystem restoration of disturbed sites because target species became dominant over time.

Restoring Limestone Quarries: Hayseed, Commercial Seed Mixture or Spontaneous Succession?

AbstractThe main goal of quarry restoration is to convert degraded, unproductive areas into new, self‐sustaining ecosystems that develop into highly natural environments. With the aim to individuate the best practices for restoring limestone quarries, we investigated the short‐term effects on vegetation features and economic advantages of three restoration approaches. These approaches included tree and shrub planting, no herb layer, or a commercial seed mixture or hayseed. The different approaches were tested in a limestone quarry within the Botticino extractive basin (N‐Italy). A donor grassland area of hayseed and a quarry area that had undergone spontaneous revegetation over a decade were used as control areas. We surveyed the vegetation plots to investigate the structure and the productivity of the herbaceous layers; collecting data on plant species cover, the mean plant height, the tree and shrubs mortality and biomass enabled us to perform gradient analysis. The main differences between the sites were due to biotic factors; specifically, vegetation cover was affected quite differently by the different restoration approaches. Restoration with commercial seed mixture resulted primarily in dense stands of Lolium perenne that caused an increase in shrub and tree mortality. Cost–benefit analysis showed that despite hayseed being the most expensive approach in terms of cost and time, it ensured higher species diversity, vegetation structure and greening. Our results highlighted that autochthonous plant materials can improve excavation‐areas restoration by both contrasting the colonisation of non‐native species and increasing natural regeneration and biodiversity levels. Copyright © 2013 John Wiley & Sons, Ltd.

Restoration of grasslands on ex-arable land using regional and commercial seed mixtures and spontaneous succession: Successional trajectories and changes in species richness

Dry grasslands in the Protected Landscape Area and Biosphere Reserve of the White Carpathian Mts. in the eastern part of the Czech Republic, central Europe, belong to the species richest plant communities (on a scale of a few m2) in the world. Many of the grasslands were converted to arable land in the second half of the 20th century, but in the past two decades many of the arable fields have been re-grassed, most of them using commercial low-diversity clover-grass seed mixtures, some of them however by spontaneous succession or using a regional species-rich seed mixture. We asked how grasslands restored in various ways differ in their successional trajectories towards long-existing grasslands as reference sites, particularly in species richness and participation of target species.Altogether 35 grasslands restored with a regional seed mixture, 31 restored with commercial seed mixtures, and 16 restored by means of spontaneous succession were compared based on vegetation records (species cover in 5m×5m plots). The data were processed using multivariate statistics.Grasslands restored in the three different ways converged in their species composition and developed generally towards reference grasslands. Considering the number of target grassland species, sowing of regional seed mixtures was the most successful, especially in the beginning, but processes of spontaneous succession led virtually to the same number of target species, even at sites re-grassed with commercial seed mixtures, but more slowly. Development of sites re-grassed spontaneously and by sowing commercial seed mixtures led to the establishment of more mesic vegetation (Arrhenatherion) than when using the regional seed mixture, which was predominantly composed of species typical of dry grasslands (Bromion). Thus, restoration of the most valuable dry grasslands should preferably be based on using properly designed regional seed mixtures.

Cladonia lichens as the most effective and essential pioneers in strongly contaminated slag dumps

Abstract The epigeic lichen biota of ten post-smelting slag dumps were studied to identify the ecological importance of Cladonia species in spontaneous succession within artificial areas. Species diversity, abundance, constancy and cover indices were determined at the initial stages of vegetation establishment. Substrates under lichen vegetation were characterised in terms of the pH, organic C and total N content, C/N ratio and Zn, Pb, Cd and As concentration. Species occurrence and abundance indices were related to habitat type, enabling the ability to identify species-specific responses to environmental factors. Despite the unfavourable and artificial habitat conditions at dump sites, some Cladonia appear abundant and form swards, with Cladonia rei as a dominant species. They appear to be well-adapted for slag substrate and their special arrangement illustrative of site contamination. Certain sward-forming Cladonia lichens play a fundamental role as effective pioneers in the initial stage of succession and provide stable plant cover development.

Afforestation or natural succession? Looking for the best way to manage abandoned cut-over peatlands for biodiversity conservation

We investigated the plant species diversity in patches with natural non-forest vegetation (NN), with forest communities that had developed where there was a spontaneous succession of vegetation (called: natural forests, NF), and with planted forests (PF) within cut-over peatlands located in central Poland. We studied (1) how diverse is plant composition in actively managed and in abandoned cut-over peatland areas, (2) how does afforestation influence wetland species composition, and (3) does natural plant succession in abandoned cut-over peatlands favour peatland regeneration and the maintenance of typical peatland species. We also defined the ecosystem services (with special attention to supporting services) and we analysed the conflicts and synergies of two cut-over peatland utilization options (abandonment and conventional forestry).An ANOVA test was used to analyse statistical differences in the diversity index, phytosociological units and Ellenberg index. Ecological conditions of NN, NF and PF were described on the base of Ellenberg indicator values (EIVs). A modified permutation test using mean randomized EIVs was used to check the significant differences in Ellenberg values.The results show that the vegetation of NN, NF and PF areas differ significantly in mean number of species, Shannon diversity and evenness index. The analyses of Ellenberg values indicated that the light and moisture conditions of NN, NF and PF differ markedly. The development of forest cover, both natural and anthropogenically created, leads to an increase in plants species diversity. However, the encroachment of numerous shade-tolerant forest species does not compensate for the reduction in characteristic peatland species. The afforestation of degraded peatland areas may be an option for management, but in every single case the decision for afforestation ought to be preceded by the recognition of the initial state of the species richness of degraded and potentially managed wetland. The most valuable wetlands with preserved peatlands flora should be actively restored for biodiversity conservation.

Changes in plant community composition and structure following restoration of maritime communities1

Old field succession has been reviewed extensively in many community settings; however, secondary succession in maritime communities, especially forest and shrub communities is poorly understood. Maritime communities of the North American Atlantic coast are unique and often fragmented ecosystems that provide critical stopover sites for migratory birds. Historical losses coupled with rising developmental pressures have created the need for conservation and restoration to protect these globally rare communities. We examined secondary succession by analyzing the vegetation community composition and soil seed bank of an abandoned agricultural field initially and at seven years (2009) after initiation of state-agency site restoration that used a combination of active and passive restoration techniques. The restoration field was divided into three projected habitats: early maritime forest (16 ha), maritime shrub (12 ha), and coastal grassland (8 ha). A trend was observed with loss of species richness across habitat types. There was a high proportion of species turnover, yet there were no significant differences in the number of species belonging to functional groups for each habitat between the two sampling years (2003 and 2009). Zones where active restoration techniques were used were more indicative of restoration success compared to areas that relied on spontaneous succession. Long-term vegetation surveys are critical to assess the success of restoration operations, and to describe and predict successional trajectories. Accessible vegetation survey data may become increasingly important in the future as land managers place more emphasis on protecting and restoring these overdeveloped, unique coastal communities.

Spontaneous succession on opencast mining sites: implications for bird biodiversity

Summary Remediation of lands devastated by industry includes various forms of restoration, such as technical reclamation and spontaneous succession. These management approaches are debated regarding conservation strategies for postindustrial landscapes. Mining areas consisting of early‐ to late‐developmental stages of both reclaimed and unreclaimed sites offer an opportunity to examine the roles of restoration strategies in a complete successional series for biodiversity and disentangle the contributions of particular biotopes available at postindustrial sites. Using linear models and multivariate analysis, I tested the effects of (a) developmental stages from early successional sites to mature forests, combined with (b) the initiation process at the sites, which was either technical reclamation or spontaneous succession, and (c) vegetation cover on (i) species richness, (ii) rarity and (iii) species composition of bird communities on 60 plots (100 × 100 m) within opencast mining areas in the lignite basin of north‐western Czech Republic. Bird communities were consistently more species rich on spontaneously developed sites compared with reclaimed sites throughout all stages of the succession series. Species richness increased with site age due to increasing habitat heterogeneity. The conservation value of bird communities was generally lower on reclaimed sites than on spontaneously developed sites and decreased with site age. The most valuable communities developed on early successional sites and native shrublands, because these were inhabited by specialists that were scarce in the surrounding landscape. By contrast, technically reclaimed sites resulted in impoverished communities, usually with narrow spectra of common species. Synthesis and applications. The results highlight the importance of spontaneously established sites and complete succession series for developing valuable bird communities in postindustrial areas such as opencast mining sites. In particular, early successional sites and shrublands create refuges for early successional specialists disappearing from the common landscape and these should be promoted at the expense of reclaimed sites wherever possible. My results support an effort for systematic implementation of early successional sites into conservation practice.

Sandpits provide critical refuge for bees and wasps (Hymenoptera: Apocrita)

Evidence-based conservation allows the evaluation of both the collateral benefits and the drawbacks of a wide range of human activities, like quarrying. In this study, the community structure of bees and wasps (Hymenoptera:Apocrita) in Central European sandpits was investigated, focusing on the changes caused by quarrying cessation and technical reclamation, as well as on the changes caused by spontaneous succession leading to the increased availability of food resources but also to the loss of the number and size of available bare sand patches. The bees and wasps demonstrated an exceptional ability to colonize the newly emerging sand quarrying areas, and to survive in them unless these were quarried as intensively as to not allow the development of any early successional vegetation. Both active and closed sandpits were found to serve as important regional refuges for the persistence of many rare species. In total, 221 species were detected, 53 of those were red-listed, with two species thought to be regionally extinct. Typically, active quarrying was associated with the presence of Bembecinus tridens, Halictus subauratus, H. maculatus, and Andrena nigroaenea. The list of the species of conservation interest is provided, and so is the detailed analysis of the life-history traits of the species in relation to the presence of bare sand patches, vegetation cover, quarrying intensity, and time elapsed since the formation of each artificial habitat patch. Sandpits as refuges for xerothermophilous and psammophilous hymenopterans are usually completely and irreversibly lost if the current legislature enforcing the technical reclamation over spontaneous or assisted succession is applied in all or most of the post-mining areas.

Dominant trees affect microbial community composition and activity in post-mining afforested soils

The aim of this work was to quantify the effects of vegetation on the activity of extracellular enzymes in the litter and soil. To achieve this, we investigated a set of post-mining sites in a brown-coal mine deposit area near Sokolov, Czech Republic. The sites were 22–33 years old and had been established on the same initial substrate by planting with six tree genera or leaving for spontaneous revegetation, with four replicate sites per vegetation type. The activity of extracellular hydrolytic and oxidative enzymes and the microbial community composition of the litter and topsoil were compared in the spring, summer and autumn using the dominant tree, pH, soil nutrient content and soil moisture as the explanatory variables. Sites under individual trees exhibited significant differences in the chemical properties of both the litter and soil, and the tree effect was identified as the most important factor affecting the activity of extracellular enzymes either directly or in the interaction with seasonal effects, although not all pairs of tree species were significantly different from each other. Seasonal effects on enzyme activity were only important in the litter. The effects of dominant trees and of seasons contributed equally to the variation in the microbial community composition at individual sites. Only a minor part of the tree effect could be explained by differences in the litter or soil chemistry. Among the chemical variables, the N content most affected the microbial biomass content, increasing fungal (but not bacterial) biomass in the litter and bacterial (but not fungal) biomass in the soil. The results indicate that other factors, such as nutrient quality or the specific association of microorganisms with rhizospheres of different trees or the understory, are likely important mediators of the vegetation effects. When comparing the revegetated sites with sites under spontaneous succession, the enzyme activities and microbial biomass were similar except for the sites revegetated with Alnus which may indicate similar rates of soil development at revegetated and succession sites. Spontaneous succession in temperate Europe may thus be a suitable option for land restoration.

Species introduction – a major topic in vegetation restoration

Holzel, N. (corresponding author, nhoelzel@uni-muenster.de): Institute of Landscape Ecology, University of Munster, Robert-Koch-Str. 28, 48149, Munster, Germany Buisson, E. (elise.buisson@univ-avignon.fr) & Dutoit, T. (thierry.dutoit@univ-avignon.fr): Institut Mediterraneen d’Ecologie et de Paleoecologie (UMR CNRS/IRD), IUT, Universite d’Avignon et des Pays de Vaucluse, site Agroparc BP 61207, 84 911, Avignon Cedex 09, France