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Retention of trees from the previous generation is one of the most widespread conservation practices in forests used for timber production. Despite the comparatively long history of this approach in Europe, there is a lack of long-term studies on the effectiveness of retention trees in preserving epiphyte communities. We compared the diversity of bryophyte and lichen species on retention trees in 20 young forest stands in Latvia in two assessments, 11 years and 18 years after clearfelling. Linear mixed-effects models showed that richness of both lichens and bryophytes remained stable during the assessment years, while bryophyte cover and diversity on retention trees increased over time. The main indicator of higher species richness, cover and diversity on retention trees in managed forests in hemi-boreal vegetation zone was the tree species, with deciduous trees playing the key role. They also provided essential habitat for rare species. Regarding bryophytes, ash, elm, and aspen can be suggested as more efficient retention trees, thus aiding the continuity of bryophyte succession in young forest stands. For lichens, lime could also be prioritised. [ABSTRACT FROM AUTHOR]

Recent studies have shown the crucial role of plant cover in the spectral signals of remote sensing images. However, how plant species cover affects the spectral-species diversity relationship remains largely unknown. To clarify this, we conducted a study in wetlands and obtained high spatial resolution multispectral images collected by unmanned aerial vehicles (UAVs). Quadrat information was obtained through a field survey. The traditional species diversity indexes and Hill numbers of each quadrat were computed by species density and cover. The mean, standard deviation, and coefficient of variation of the normalized difference vegetation index (NDVI) were computed based on the multispectral images. We employed univariate and multivariate regression models to assess the ability of spectral information to predict species diversity and the explanatory degree of variables to the multivariate regression models were decomposed. The results showed that rather than species density, spectral indexes were more strongly related to species diversity indexes computed by species cover, and the robustness and universality of the methods that predict plant species diversity based on spectral indexes have been improved by considering species cover. Meanwhile, in light of the flexibility of Hill numbers that assign different weights to dominant and rare species in the community, we believe that Hill numbers are the better choice in the spectral-species diversity studies, which can suitable to various communities with different density-cover relationships. In addition, our study also provided an insightful perspective for future spectral-plant species diversity research.

Abstract Key message Fifteen species are most susceptible to require vegetation control during tree regeneration in the range of our study. Among these 15 species, Rubus fruticosus, Pteridium aquilinum, and Molinia caerulea cover each more than 300,000 ha of open-canopy forests. Context Vegetation control, i.e., the reduction of competitive species cover, is often required to promote tree seedling establishment during the forest regeneration stage. The necessity to control understory vegetation largely depends on the species to be controlled. In order to plan forest renewal operations, it is critical to identify which species require vegetation control during the regeneration stage and to quantify the forest area affected by these species. Aims We aimed at identifying the main species requiring vegetation control and at estimating the forest area they cover at the national level. Methods Using National Forest Inventory data, we created four indicators based on two levels of plant cover, cross-referenced with two levels of canopy opening, and compared them to the outcome of a survey of forest manager practices. Results The best indicator was the one that represented the proportion of forests with open canopy where the species was present with a large cover in the understory. In non-Mediterranean France, according to the indicator, a total of 15 species were found to frequently require vegetation control during the tree regeneration stage. Pteridium aquilinum, Molinia caerulea, and Rubus fruticosus were the main species, and each covered more than 300,000 ha of forest with open canopies, representing about 13% of the total forest area with open canopies outside of the Mediterranean area. Conclusions Forests covered by species requiring vegetation control according to forest managers represent a large share of the forest area undergoing regeneration. This study provides the first list of species that require vegetation control based on a methodological protocol that makes it possible to calculate the area associated with each species.

Key message: Fifteen species are most susceptible to require vegetation control during tree regeneration in the range of our study. Among these 15 species, Rubus fruticosus, Pteridium aquilinum, and Molinia caerulea cover each more than 300,000 ha of open-canopy forests. Context: Vegetation control, i.e., the reduction of competitive species cover, is often required to promote tree seedling establishment during the forest regeneration stage. The necessity to control understory vegetation largely depends on the species to be controlled. In order to plan forest renewal operations, it is critical to identify which species require vegetation control during the regeneration stage and to quantify the forest area affected by these species. Aims: We aimed at identifying the main species requiring vegetation control and at estimating the forest area they cover at the national level. Methods: Using National Forest Inventory data, we created four indicators based on two levels of plant cover, cross-referenced with two levels of canopy opening, and compared them to the outcome of a survey of forest manager practices. Results: The best indicator was the one that represented the proportion of forests with open canopy where the species was present with a large cover in the understory. In non-Mediterranean France, according to the indicator, a total of 15 species were found to frequently require vegetation control during the tree regeneration stage. Pteridium aquilinum, Molinia caerulea, and Rubus fruticosus were the main species, and each covered more than 300,000 ha of forest with open canopies, representing about 13% of the total forest area with open canopies outside of the Mediterranean area. Conclusions: Forests covered by species requiring vegetation control according to forest managers represent a large share of the forest area undergoing regeneration. This study provides the first list of species that require vegetation control based on a methodological protocol that makes it possible to calculate the area associated with each species. [ABSTRACT FROM AUTHOR]

Scots pine (Pinus sylvestris L.) is a dominant tree species on nutrient-poor sandy soils in the Baltic region's hemiboreal forests. A final clear-cut in commercial stands is a common practice. However, the maintenance of relatively stable vegetation indices and ecological processes throughout the rotation promote new scientific and social debates. Overall, clear-cuttings disturb forest functions for a certain period, i.e., phytocenoses with forest-based species composition, biodiversity, and vegetation cover. Soil organic carbon (SOC) and nutrients can also be affected. As key indices, ground vegetation, SOC and main nutrients in the forest floor and in 40-cm topsoil layer were analysed in the clear-cuttings (not reforested) and in reforested 10-, 30-, and 101-year-old Scots pine stands in 2020. The results show an increase in species richness at the beginning of stand formation up to 30 years after clear-cutting; species typical of a mature forest occurred relatively quickly post-harvest. The mean mass of forest floor vegetation was negatively related to the richness of ground vegetation species. Forest floor pH consequently decreased with stand age. Higher SOC levels were in the mature stand. In the mineral topsoil layers, total SOC and total nitrogen were in the upper 10-cm layer in the 30-year-old stand. A post-harvest peak in mineral N concentration was observed and other nutrients, especially mobile P2O5, K2O, Ca2+ and Mg2+, increased the clear-cuttings and in the 10-year-old stand compared to the mature stand. [ABSTRACT FROM AUTHOR]

Abstract Premise The point‐intercept method is one of the most commonly used approaches to measure species cover in ecosystems worldwide. In this approach, multiple points are sampled for presence/absence of a species, and the number of present points divided by the total number of sampled points provides an estimate of percent cover. Our purpose is to mathematically analyze the accuracy of the point‐intercept approach and establish guidelines for its use. Methods We developed formulas that analyze the point‐intercept method and confirmed their effectiveness using simulations. Results We find that a point‐intercept spacing of at least 80% of the largest plant diameter provides the most reliable results. We present a user‐friendly spreadsheet that calculates the number of intercepts needed for fieldwork, as well as the standard deviation, expected deviation, and confidence interval of the collected data. Discussion We provide a variety of guidelines for establishing field protocols based on our results, including dealing with rare species and combining results for multiple species. Quadrat characteristics (intercept spacing, number of point intercepts) can now be easily calculated to guide research design prior to fieldwork; after fieldwork is complete, the accuracy of this technique can (and should) be reported in all future ecological studies in which it is used.

Premise: The point‐intercept method is one of the most commonly used approaches to measure species cover in ecosystems worldwide. In this approach, multiple points are sampled for presence/absence of a species, and the number of present points divided by the total number of sampled points provides an estimate of percent cover. Our purpose is to mathematically analyze the accuracy of the point‐intercept approach and establish guidelines for its use. Methods: We developed formulas that analyze the point‐intercept method and confirmed their effectiveness using simulations. Results: We find that a point‐intercept spacing of at least 80% of the largest plant diameter provides the most reliable results. We present a user‐friendly spreadsheet that calculates the number of intercepts needed for fieldwork, as well as the standard deviation, expected deviation, and confidence interval of the collected data. Discussion: We provide a variety of guidelines for establishing field protocols based on our results, including dealing with rare species and combining results for multiple species. Quadrat characteristics (intercept spacing, number of point intercepts) can now be easily calculated to guide research design prior to fieldwork; after fieldwork is complete, the accuracy of this technique can (and should) be reported in all future ecological studies in which it is used. [ABSTRACT FROM AUTHOR]

Questions: We asked how plant community composition responded to experimentally produced warmer and drier climate conditions at the landscape scale with existing variation in local species composition and environmental conditions. We aimed to identify changes in community composition overall and the species with greatest response in abundance, and hypothesized that locally restricted species may be more sensitive to warming than more widespread species within the landscape based on the assumption that they have a narrower niche breadth with respect to environmental conditions. Location: Semiarid, northern Mongolian steppe. Methods: Open‐top passive warming chambers (OTCs) elevated temperatures at two slope locations that differed in elevation, degree of slope, environmental conditions, and species composition. The OTC treatment was crossed with watering on the drier upper slope. Community composition differences among treatments were examined using canonical analysis of principal coordinates (CAP), which identified species contributing the most to differences. In response to warming, we also compared species locally restricted to one slope location with locally widespread species. Results: Open‐top passive warming chambers affected community composition more where soil moisture was greater, at the lower slope location and where warming was combined with supplemental watering on the drier upper slope. Locally restricted species responded negatively to the OTC while locally widespread species showed no overall response. Conclusions: Community composition responses to warming differ even within the landscape over and above the initial differences that exist in community structure and abiotic factors. Our results suggest that a warmer and drier climate will impact community composition sooner under more mesic conditions, affect locally restricted species more strongly, and reduce variation in species composition across the landscape. To better predict community responses to future warming, we must consider combined and interactive effects with changes in precipitation and extant water availability. [ABSTRACT FROM AUTHOR]

Aims: Certain parts of the growing season have been proposed as optimal for recording relevant relevés of forests and dry grasslands and so the monitoring of these vegetation types has become more time‐ and cost‐effective. We investigated whether it is possible to propose an optimal period during the year for making relevant relevés of emergent wetland vegetation. Location: Marshlands of the central Balkan Peninsula. Methods: One hundred and eighty‐five permanent vegetation plots were investigated in three distinct time periods: spring, summer and autumn. In order to identify the communities, cluster analyses were carried out, and diagnostic species for each cluster were determined. The potential for temporal change of the communities regarding the species and life form composition was assessed using PERMANOVA and NMDS analyses. The Friedman test was used to assess the significance of seasonal change in the communities regarding their species richness, recordability and Shannon diversity. Results: The level of floristic similarity among the 11 phytocoenoses analyzed significantly varied over the growing season while the composition in terms of their diagnostic species remained unchanged. The majority of the communities showed statistically significant seasonal changes in the qualitative and quantitative characteristics of the vegetation, life form composition and cover. Although different communities expressed significant modifications in these parameters between different pairs of seasons, all of them showed changes in the mentioned parameters between spring and autumn. The degree of intra‐annual variation in the species richness, species recordability and Shannon diversity was low in almost all phytocoenoses. Conclusions: Summer is the optimal period for recording most of the species from the total list of the communities developed on hydrologically stable habitats, while spring is more appropriate for making relevés on periodically inundated habitats. The sampling time has negligible impact on the classification of associations but it could have important implications for the classification of higher‐ranked syntaxonomic units of the class Phragmito‐Magnocaricetea. [ABSTRACT FROM AUTHOR]

Novel mapping methods using AI have led to improved mapping of the extent of drainage systems, but the full scope of the effects of drainage on ecosystems has yet to be understood. By combining ditches mapped with remote sensing and AI methods with soil data from the Swedish Forest Soil Inventory, and vegetation data from the National Forest Inventory we identified 4 126 survey plots within 100 m of a ditch. The inventory data span across three biomes; the northern boreal zone, the hemiboreal zone, and the temperate zone. We explored if soils and vegetation close to ditches were indeed different from the surrounding landscape. The large number of plots spread widely across the Swedish forest landscape spanning different physiographic regions, climates, topography, soils, and vegetation made it possible to identify the general effect of drainage on soil properties, tree productivity, and plant species composition. We found a surprisingly large amount of ditches on mineral soils (50–70%, depending on the definition of peatlands). Forest growth was affected, with higher growth rates of trees closer to ditches, particularly Norway spruce. Sphagnum mosses – a key indicator of wet soils - were less common near ditches, where they were replaced by feather mosses. The soil bulk density was higher closer to ditches, as was the concentration of metals that are typically associated with organic matter (Al), while concentrations of metals with a lower affinity for organic material decreased toward ditches (Na, K, Mg). The results from mineral soils and peat soils often differed. For example, N and tree volume increased toward ditches, but on different levels for peat and mineral soils, while the thickness of the humus layer and Pleurozium schreberi cover showed opposite patterns for the different soils. Clearly, ditches have affected the entire Swedish forest landscape, driving it towards a drier, more spruce-dominated productive forested ecosystem and away from wetland ecosystems like mires and littoral areas along streams. Furthermore, the biogeochemistry of the soils and understory species cover near ditches have changed, potentially irreversibly, at least within human time frames, and have implications for restoration goals and the future of forestry. • 50-70% of the drainage systems were found on mineral soils. • Ditches have changed the soil biogeochemistry. • Ditches have increased the tree volume and growth. • Ditches have changed understory species coverage. [ABSTRACT FROM AUTHOR]

The aim of this work was to answer the question wheather woodland can be established spontaneously in a variety of disturbed sites. We analyzed 10 successional series lasting at least 80 years which were located across the Czech Republic, central Europe. The woody species were classified into early and late successional species. Species typical for the respective potential natural vegetation described for Czech woodland were considered as late successional while all the other species were classed as early successional. Data were processed using multivariate analyses and GLM. Cover and the number of woody species gradually increased during succession, and woodland established spontaneously in all series. The relative cover of early successional species reached its peak on average after 40–50 years of succession or gradually decreased in the model since the first year of site abandonment while that of late successional species gradually increased. However, the series largely differed and some of them did not follow the trends. Betula spp. (early) appeared to be by far the most frequent colonizer followed by Pinus sylvestris (late). Spontaneous establishment of woodland can be an effective method for ecosystem restoration in a range of disturbed sites within central Europe. Proportion of alien species was mostly low. [ABSTRACT FROM AUTHOR]

Grasslands are one of the ecosystems that have been strongly affected by anthropogenic impacts. The state-of-the-art in monitoring changes in grassland species composition is to conduct repeated plot-based vegetation surveys that assess the occurrence and cover of plants. These plot-based surveys are typically limited to comparably small areas and the quality of the cover estimates depends strongly on the experience and performance of the surveyors. Here, we investigate the possibility of a semi-automated, image-based method for cover estimates, by analyzing the applicability of very high spatial resolution hyperspectral data to classify grassland species at the level of individuals. This individual-oriented approach is seen as an alternative to community-oriented remote sensing depicting canopy reflectance as the total of mixed species reflectance. An AISA + imaging spectrometer mounted on a scaffold was used to scan 1 m 2 grassland plots and assess the impact of four sources of variation on the predicted species cover: (1) the spatial resolution of the scans, (2) complexity, i.e. species number and structural diversity, (3) the species cover and (4) the share of functional types (graminoids and forbs). Classifications were conducted using a support vector machine classification with a linear kernel, obtaining a median Kappa of ~ 0.8. Species cover estimations reached median r 2 and root mean square errors (RMSE) of ~ 0.6 and ~ 6.2% respectively. We found that the spatial resolution and diversity level (mainly structural diversity) were the most important sources of variation affecting the performance of the proposed approach. A spatial resolution below 1 cm produced relatively good models for estimating species-specific coverages (r 2 = ~ 0.6; RMSE = ~ 7.5%) while predictions using pixel sizes over that threshold failed in this individual-oriented approach (r 2 = ~ 0.17; RMSE = ~ 20.7%). Areas with low inter-species overlap were better suited than areas with frequent inter-species overlap. We conclude that the application of very high resolution hyperspectral remote sensing in environments with low structural heterogeneity is suited for individual-oriented mapping of grassland plant species. [ABSTRACT FROM AUTHOR]

Herbaceous plants account for more than three-fourths of the total biomass in savanna ecosystems. However, which environmental factors mainly drive the biodiversity of herbaceous species is still under debate. In this study, we investigated the influence of climate, habitat and land use on species richness and cover in the West African savanna ecosystems of Burkina Faso. For a broader understanding, we analysed responses of the most important taxonomical groups of the herbaceous layer (Poaceae, Cyperaceae, Fabaceae s.l. and juvenile woody species) to the above mentioned environmental factors. We found light limitation by trees or shrubs and nutrient availability to be the variables that were mainly able to explain the differences in species richness, whereas precipitation and soil water-holding capacity, in general, drive species cover. However, specifically which environmental parameters influenced species richness and cover differed between taxonomical groups. Species richness of Cyperaceae species depended on water availability, while high Cyperaceae cover was found in soils with high water-holding capacity. Cyperaceae species are able to tolerate stagnant water. By contrast, Poaceae species cover was higher in dry habitats, and species richness declined with higher mean annual precipitation. Fabaceae species richness and cover were both higher in communal areas and sandy soils. This study revealed that both species richness and species cover, important aspects to describe the community composition, should be examined, as they are driven by sometimes different environmental conditions. Differentiating between the most important taxonomical groups of the savanna ecosystem increases the understanding in the important ecological processes that effect the herbaceous vegetation composition. [ABSTRACT FROM AUTHOR]

Context: Urban environments create a wide range of habitats that harbour a great diversity of plant species, many of which are of alien origin. For future urban planning and management of the green areas within the city, understanding of the spatial distribution of invasive alien species is of great importance. Objectives: Our main aim was to assess how availability of different ecosystem types within a city area, as well as several parameters describing urban structure interact in determining the cover and identity of invasive alien species. Methods: We studied the distribution of chosen invasive plant species in a mid-sized city in the Czech Republic, central Europe, on a gradient of equal sized cells from the city centre to its outskirts. Results: A great amount of variation was explained by spatial predictors but not shared with any measured variables. The species cover of invasive species decreased with increasing proportion of urban greenery and distance from the city centre, but increased with habitat richness; road margins, ruderal sites, and railway sites were richest in invasive species. In contrast, the total number of invasive species in cells significantly decreased with increasing distance from the city centre, but increased with habitat richness. Conclusions: Our results suggest that different invasive species prefer habitats in the vicinity of the city centre and at its periphery and the spatial structure and habitat quality of the urban landscape needs to be taken into account, in efforts to manage alien plant species invasions in urban environments. [ABSTRACT FROM AUTHOR]

Epiphytic macrolichen lichens are important components of forest ecosystems, but their responses to stand-replacing fire and multiple successional pathways of the canopy tree layer are poorly understood., We examined the dynamics of epiphytic macrolichens following wildfire and tested the independent and interactive effects of time since fire and overstorey composition on epiphytic macrolichen abundance, diversity and composition in boreal forests of Canada. Epiphytic macrolichens were sampled in 51 stands of conifer, mixed-wood and broadleaf overstorey types ranging from 7 to 209 years since fire., Macrolichen abundance estimated as percentage cover continuously increased with stand age with highest cover in 209-year-old stands for all overstorey types. Mixed-wood and conifer stands had higher macrolichen abundance than broadleaf stands in all age classes except similarly low abundances in stands ≤15 years old for all overstorey types. Species richness of epiphytic macrolichens reached peaks in 98- or 146-year-old stands. Mixed-wood stands had higher macrolichen species richness than broadleaf and conifer stands at 98 years old, but not at other age classes. Multivariate analysis indicated that the macrolichen communities were compositionally distinct for all age classes and overstorey types., Synthesis and applications. Epiphytic macrolichen abundance continuously increases with time since fire. Our results also show that macrolichen diversity peaks at intermediate stand ages with highest diversity in mixed-wood stands. Our findings of distinct macrolichen communities supported by each age class and overstorey compositional type suggest that conservation of epiphytic macrolichen diversity would require forest managers to maintain a diverse age structure and overstorey composition in forest landscapes. [ABSTRACT FROM AUTHOR]

Mountain regions are hotspots of biodiversity and contain many endemic vascular species. The alpine vegetation is generally considered to be particularly vulnerable to climate change and can be used as a sensitive "ecological indicator" for climate change effects. We present recent (2001 and 2008) changes in vascular plant composition observed in a monitoring network across GLORIA network summits in the Central Greater Caucasus. During monitoring period average soil temperature, June mean of daily minimum T (°C) and GDD did not significantly increase. The Thermophilization indicator (D) was negative. The observed changes in species richness and cover are not generated only by the changes of these climatic variables. [ABSTRACT FROM AUTHOR]

Short-term changes in plant species number, cover, frequency, and composition were studied along an altitudinal gradient crossing 4 GLORIA summits (from 2240 m to 3024 m a.s.l.) from the treeline ecotone to the subnival zone in the Central Caucasus. Large-scale (summit area) and small-scale (16 plots of 1 m²/summit) patterns were monitored in 2001. Recording was repeated in 2008. During the monitoring period, the average soil temperature and growing-degree days did not significantly increase. After 7 years, a revisitation of the summit area revealed a considerable increase of species richness, especially at the lower alpine zone (CP1 and CP2 summits). At a small scale (1 m²), species richness also increased at the lower summit (from 12.5 ± 2.87 to 15.5 ± 3.12 species on the CP1 summit). The cover of 17 species significantly decreased, while that of 5 increased. There were significant linear relationships between species richness and altitude and climatic variables. The main newcomers were species from the lower altitudinal zones and their percentage was highest on the southern slope. Endemics and cold-adapted species were not seriously endangered. In the Central Caucasus we do not consider climate warming as the primary driver of the changes of plant richness and competition. [ABSTRACT FROM AUTHOR]

Canada's National Forest Inventory (CanFI) provides coarse-grained, aggregated information on a large number of forest attributes. Though reasonably well suited for summary reporting on national forest resources, the coarse spatial nature of this data limits its usefulness in modeling applications that require information on forest composition at finer spatial resolutions. An alternative source of information is the land cover classification produced by the Canadian Forest Service as part of its Earth Observation for Sustainable Development of Forests (EOSD) initiative. This product, which is derived from Landsat satellite imagery, provides relatively high resolution coverage, but only very general information on forest composition (such as conifer, mixedwood, and deciduous). Here we link the CanFI and EOSD products using a spatial randomization technique to distribute the forest composition information in CanFI to the forest cover classes in EOSD. The resultant geospatial coverages provide randomized predictions of forest composition, which incorporate the fine-scale spatial detail of the EOSD product and agree in general terms with the species composition summaries from the original CanFI estimates. We describe the approach and provide illustrative results for selected major commercial tree species in Canada. [ABSTRACT FROM AUTHOR]

To predict the role of ombrotrophic bogs as carbon sinks in the future, it is crucial to understand how Sphagnum vegetation in bogs will respond to global change. We performed a greenhouse experiment to study the effects of two temperature treatments (17.5 and 21.7°C) and two N addition treatments (0 and 4 g N m−2 year−1) on the growth of four Sphagnum species from three geographically interspersed regions: S. fuscum, S. balticum (northern and central Sweden), S. magellanicum and S. cuspidatum (southern Sweden). We studied the growth and cover change in four combinations of these Sphagnum species during two growing seasons. Sphagnum height increment and production were affected negatively by high temperature and high N addition. However, the northern species were more affected by temperature, while the southern species were more affected by N addition. High temperature depressed the cover of the ‘wet’ species, S. balticum and S. cuspidatum. Nitrogen concentrations increased with high N addition. N:P and N:K ratios indicated P-limited growth in all treatments and co-limitation of P and K in the high N treatments. In the second year of the experiment, several containers suffered from a severe fungal infection, particularly affecting the ‘wet’ species and the high N treatment. Our findings suggest that global change can have negative consequences for the production of Sphagnum species in bogs, with important implications for the carbon sequestration in these ecosystems. [ABSTRACT FROM AUTHOR]

Ground vegetation cover, composition and biomass were analyzed at six 7–9-year-old Norway spruce (Picea abies (L.) Karst.) stands 5 years after application of hardened wood ash. Logging residues were collected at the preceding harvest. At each site hardened crushed wood ash of two types, Nymo¨lla and Perstorp, was applied in a randomized block design (n=4). The dose applied was 3 Mg ha−1. The species composition of the ground vegetation has been used as a forest type classification systems. The present study was performed at sites with Vaccinium myrtillus forest type in four climatic zones in Sweden. In one of the climatic zones, the study also included a site fertility gradient with V. myrtillus, grass and herb forest types.The results showed that the effects of crushed wood ash application on the vegetation were limited. The bryophytes showed no visible negative response to the ash application. The presence of Perstorp wood ash appeared to have a significant suppressive effect on the cover of Calluna vulgaris, but only at V. myrtillus sites. The cover of Deschampsia flexuosa was slightly higher after wood ash application at poor V. myrtillus sites. None of the ash types affected the plant community composition significantly at V. myrtillus sites or at the herb site. However, the site with grass type possibly developed a similarity with herb type after application of the Nymo¨lla wood ash. This indicated that wood ash application might improve site fertility. But, since this tendency was limited to one ash type, it also indicates that the chemical composition of the hardened crushed wood ash seemed to be of importance for the vegetation changes, also when doses of the ash were low. The biomass of different field vegetation components was not affected by the ash application. In conclusion, application of hardened wood ash of the types used in our study and in doses up to 3 Mg ha−1 is not likely to decrease species abundance or in any other way affect biodiversity within field or bottom layer vegetation in young Norway spruce stands. [Copyright &y& Elsevier]

Lichens contribute significantly to the biodiversity and functioning of many ecosystems. Although lichens are useful air pollution bioindicators and may respond in significant ways to global change, they are studied infrequently under field conditions in chamberless exposure systems. We surveyed corticolous lichens on paper birch (Betula papyrifera) and trembling aspen (Populus tremuloides) after 10 years exposure (1998–2007) to elevated CO 2 (eCO 2) and O 3 (eO 3) in the Aspen-FACE experiment in Rhinelander, WI, USA. This experiment utilized chamberless exposure rings, 30 m in diameter, with both host trees planted together in one quadrant. Four treatments were allocated among 12 rings: ambient, eCO 2 , eO 3 , and the combination of eCO 2 + eO 3 , each replicated once in each of three blocks. Over the course of the experiment, ambient CO 2 increased from 343 to 386 ppm while eCO 2 averaged ~530 ppm CO 2. Ambient ozone concentrations averaged ~37 ppb and ~49 ppb for eO 3 although exposures decreased with time. Tree growth and leaf area index were negatively affected by eO 3 and stimulated by eCO 2 , resulting in higher photosynthetically active radiation (PAR) in eO 3 and lower in eCO 2. We assessed lichen richness and cover on five host trees per ring on the north-facing side of the trunks, which were higher on birch than on aspen. Neither of the lichen measures on birch responded to the exposure treatments, while on aspen lichen cover was highest in eO 3 and lowest in eCO 2. On aspen, lichen cover was positively related to PAR and dominated by Caloplaca. No relationship was found for birch, although Lecanora exhibited a negative relationship with PAR. These lichens were insensitive to direct effects of eCO 2 and eO 3 at the levels applied. Instead, they responded to indirect effects, such as host tree species, and changes in understory PAR, resulting from direct effects of eO 3 and eCO 2 on the host trees. Unlabelled Image • Corticolous lichens were surveyed after free-air exposure to elevated O 3 and CO 2. • Lichen richness was greater on aspen than birch trunks. • Lichen cover, richness and abundance were not directly affected by fumigants. • On aspen, lichens responded positively to higher light in elevated O 3 treatment. • No treatment response noted for lichens on birch; Indirect responses most important [ABSTRACT FROM AUTHOR]

This data set contains species-specific biomass and cover data as well as community leaf area index (LAI) and height from a large grassland biodiversity experiment (Jena Experiment). In this experiment, 82 grassland plots of 20 X 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, and tall and small herbs). In May 2002, varying numbers of plant species were sown into the plots to create a gradient of plant species richness (1,2,4, 8, 16, and 60 species) and functional richness(1, 2, 3, and 4 functional groups). Plots were maintained by biannual weeding and mowing. The data set encompasses the 2002-2008 May and August biomass harvests from 3-4 subplots of 0.2 X 0.5 m per experimental plot sorted to species. Moreover, plant species and community cover estimated in an approximately 9-m2 subplot per plot are included in the data set. Each biomass harvest was accompanied by measurements of vegetation height and LAI per plot. Analyses of the community biomass data have identified species richness as well as functional group composition as important drivers of a positive biodiversity-productivity relationship. The data set can be used to study a variety of questions about how plant community composition and structure respond to changes in species richness and functional diversity over time. Sampling is ongoing, and new data will be added. [ABSTRACT FROM AUTHOR]