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The question of the efficient plot size for sampling vegetation has been discussed many times, but aquatic vegetation is rarely considered. Here we examine a dataset of aquatic (267) and littoral (456) vegetation samples from 60 sandpits across the Czech Republic to determine appropriate plot size while trying to maximise both efficiency and accuracy of the sampling effort. A dataset of littoral vegetation samples was used for comparison in some analyses. The cover of vascular plant species was estimated in nested plots of 1, 4 and 16 m2. Age of sampled plots ranged from 1 to 63 years. Besides species identity itself, basic life-history species traits were considered in the comparison of different plot sizes. Effect of plot size on different ordination patterns was evaluated with Procrustean analyses and the Monte Carlo permutation test. The size categories differed in number of species and species dominance (Simpson index). No significant differences were found between plot sizes in ordinations of aquatic vegetation, neither for species composition nor for the composition of species traits. Our study indicates that aquatic vegetation samples of different size between 1 and 16 m2 are comparable, especially if species functional groups are used instead of species identity. Analyses of successional changes and the influence of environmental variables should not be significantly affected by the plot size used for sampling the vegetation when cover data are used. The different plot sizes did not affect the description of successional trends.

A systematic analysis of vegetation successions following disturbance can outline general invasion patterns and contribute to the management of disturbed and natural ecosystems. Here the participation of alien plant species, with special regard to neophytes, was compared in 20 types of successional series in the Czech Republic, central Europe, to detect possible trends and factors supporting their occurrence. Based on 3473 samples of spontaneously established vegetation, we used linear mixed models and multivariate analyses to assess how alien species were influenced by successional age, average annual temperature and precipitation, altitude, geological substrate, and surrounding land-cover. Out of 1035 plant taxa recorded, 839 were natives, 129 archaeophytes and 67 neophytes. The primary or secondary status of series may influence the participation of neophytes but was not determinative. The most invaded successional series were those in deforested landscapes at lower altitudes. Altitude plus climate, substrate and degree of urbanisation shaped the general vegetation pattern and occurrence of aliens. Neophytes were additionally benefited by density of roads and railways and extent of arable land in the surrounding landscape, confirming that these land uses are relevant invasion pathways and should be targeted in prevention strategies. Alien participation is low and mostly declines in later stages, with few neophytes becoming locally dominant over time. This supports spontaneous succession as a suitable restoration option and places the focus on an early detection of potentially problematic species. These findings may contribute to guiding decisions in landscape restoration and the management of disturbed sites under central European conditions.

The EU Nature Restoration Law could rapidly advance ecosystem restoration also in cities. Yet the law focuses on green cover but ignores the ecological quality and biodiversity of urban green spaces, although these are crucial for making cities truly sustainable. Therefore, countries must now define ambitious biodiversity targets and implement urban ecosystem restoration. We propose nine key actions to speed up this process and mainstream urban ecological restoration.

QUESTIONS: (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? LOCATION: Extracted 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. METHODS: Phytosociological 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. RESULTS: The 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. CONCLUSIONS: The 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.

QUESTIONS: Although 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. LOCATION: White Carpathian Mts., eastern Czech Republic (48°50′–49°05′ N, 17°19′–17°55′ E, 250–610 m a.s.l.). METHODS: We 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. RESULTS: The 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. CONCLUSIONS: Sowing 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.

QUESTIONS: (1) Do 17 seres studied proceed towards corresponding potential natural vegetation; (2) what are the similarities between seral and potential natural vegetation, and is it possible to estimate how long it takes to reach potential natural vegetation; and (3) do primary and secondary seres differ? LOCATION: Extracted peatlands, corridors of the former iron curtain, artificial fishpond islands and barriers, sedimentary basins, various spoil heaps after mining, various stone quarries, forest clearings, burned‐down forests, road verges, sand and gravel‐sand pits, river gravel bars and abandoned arable fields located in various parts of the Czech Republic. METHODS: Seral stages were sampled by phytosociological relevés (2602). The following categories of successional age were considered: early (1–10 yrs), intermediate (11–25 yrs) and late (>25 yrs). Phytosociological relevés (386) representing corresponding potential natural vegetation were extracted from the National Phytosociological Database. DCA and CCA ordinations were performed to compare the pattern of seral stages with potential natural vegetation and between primary and secondary seres. Dissimilarity between seral stages of primary and secondary successions and the corresponding potential natural vegetation was further assessed using the Bray‐Curtis dissimilarity measure. Extrapolation was performed to estimate when the seres will reach the stage corresponding to potential natural vegetation. RESULTS: The ordination showed that successions proceeded towards the corresponding potential natural vegetation and reflected substrate pH, site moisture and successional age. The estimated average time needed to reach potential natural vegetation was about 180 yrs for primary successions and about 260 yrs for secondary successions, considering presence–absence species data, and 200 and 250 yrs, respectively, considering cover data. All species recorded in potential natural vegetation (421) were also recorded in seral vegetation. CONCLUSIONS: In the general view across the high number of seres spread over the whole country, successions advanced in the direction of the corresponding potential natural vegetation. The extrapolated recovery of potential natural vegetation is faster in primary seres than in secondary ones, and seres sooner resemble the corresponding potential natural vegetation in species composition than in vegetation structure.

Questions: What is the variability of succession over a large geographical area? What is the relative importance of (1) local site factors and (2) landscape factors in determining spontaneous vegetation succession? Location: Various regions of the Czech Republic, Central Europe. The regions represent two categories characterized by agrarian lowlands, with a relatively warm and dry climate, and predominant woodland uplands with a relatively cold and wet climate. Methods: Gravel-sand pits ranged in age from 1–75 years since abandonment. Three types of sites were distinguished: dry, wet and hydric in shallow flooded sites. Vegetation relevés were recorded with species cover (%) visually estimated using the space-for-time substitution approach. Local site factors, such as water table and soil characteristics, and landscape characteristics, namely climatic parameters, presence of nearby (semi-) natural plant communities and main land cover categories in the wider surroundings, were evaluated. Results: Ordination analyses showed that water table was the most important local site factor influencing the course of spontaneous vegetation succession. Succession was further significantly influenced by soil texture, pH, macroclimate, the presence of some nearby (semi-) natural communities and some land cover categories in the wider surroundings. Spontaneous vegetation succession led to the formation of either shrubby grassland, deciduous woodland, Alnus and Salix carrs, and tall sedge or reed and Typha beds in later stages depending predominantly on the site moisture conditions. Conclusions: Although the water table was the most influential on the course of vegetation succession, the landscape factors together explained more vegetation variability (44%) than local site factors (23%). Nomenclature: Kubát et al. (2002).

Questions Our study examined the relationships between the seed bank and above‐ground vegetation in spontaneously revegetated and forestry‐reclaimed sand pits. We asked the following questions: (a) What is the composition of the seed bank and above‐ground vegetation? (b) How do they develop over the course of succession within the two different restoration approaches? (c) What is the representation of target and undesirable species in the seed bank and above‐ground vegetation? and (d) Could the seed bank serve as the source for target vegetation restoration? Location Třeboň Basin, Czech Republic. Methods Three successional stages and two types of restoration approaches were considered. Bray–Curtis similarity was used for describing the similarity between above‐ground vegetation and the seed bank. Representation of target (dry sandy grassland), desirable (woodland, wetland, mesic grassland) and undesirable (synanthropic) species was assessed. Results The type of restoration approach exhibited stronger effects on the above‐ground vegetation than on the seed bank. The similarity between the seed bank and above‐ground vegetation decreased during succession. Undesirable species formed the dominant species group in the seed bank regardless of successional stage and the type of restoration approach. Target species were represented especially in the above‐ground vegetation of young successional stages. Only half of the number of target species appeared in the seed bank in comparison to above‐ground vegetation and their number further rapidly decreased in older stages of succession. Conclusions The result showed that the seed bank of sand pits could be considered as a potential resource mainly for synanthropic species, but it cannot serve as the only source for the eventual restoration of the target vegetation of an open sandy dry grassland after potential clearing, once it becomes overgrown by forest. Consequently, maintaining young successional stages is desirable if we wish to support species typical of dry sandy grassland. We examined the relationships between the seed bank and aboveground vegetation in spontaneously revegetated and forestry reclaimed sand pits. Our results showed that the seed bank of sand pits cannot serve as the only source for the restoration of target vegetation. Maintaining young successional stages is desirable if we wish to support species typical of dry sandy grassland.

Open interior sands represent a highly threatened habitat in Europe. In recent times, their associated organisms have often found secondary refuges outside their natural habitats, mainly in sand pits. We investigated the effects of different restoration approaches, i.e. spontaneous succession without additional disturbances, spontaneous succession with additional disturbances caused by recreational activities, and forestry reclamation, on the diversity and conservation values of spiders, beetles, flies, bees and wasps, orthopterans and vascular plants in a large sand pit in the Czech Republic, Central Europe. Out of 406 species recorded in total, 112 were classified as open sand specialists and 71 as threatened. The sites restored through spontaneous succession with additional disturbances hosted the largest proportion of open sand specialists and threatened species. The forestry reclamations, in contrast, hosted few such species. The sites with spontaneous succession without disturbances represent a transition between these two approaches. While restoration through spontaneous succession favours biodiversity in contrast to forestry reclamation, additional disturbances are necessary to maintain early successional habitats essential for threatened species and open sand specialists. Therefore, recreational activities seem to be an economically efficient restoration tool that will also benefit biodiversity in sand pits.

Seed characteristics play an important role in the colonization and subsequent persistence of species during succession in disturbed sites and thus may contribute to being able to predict restoration success. In the present study, we investigated how various seed characteristics participated in 11 spontaneous successional series running in different mining sites (spoil heaps, extracted sand and sand-gravel pits, extracted peatlands, and stone quarries) in the Czech Republic, Central Europe. Using 1864 samples from 1- to 100-years-old successional stages, we tested whether species optimum along the succession gradient could be predicted using 10 basic species traits connected with diaspores and dispersal. Seed longevity, diaspore mass, endozoochory, and autochory appeared to be the best predictors. The results indicate that seed characteristics can predict to a certain degree spontaneous vegetation succession, i.e., passive restoration, in the mining sites. A screening of species available in the given landscape (regional and local species pools) may help to identify those species which would potentially colonize the disturbed sites. Extensive databases of species traits, nowadays available for the Central European flora, enable such screening.