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The high proportion of woody plant species on oceanic islands has hitherto been explained mainly by gradual adaptation to climatic conditions. Here, we present a novel hypothesis that such woodiness is adaptative to volcanic ash (tephra) deposition. Oceanic islands are subject to frequent eruptions with substantial and widespread ash deposition on evolutionary time scales. We postulate that this selects for woodiness through an increased ability to avoid burial of plant organs by ash, and to re-emerge above the new land surface. We sense-checked using observations of plant occurrences and distributions on La Palma (Canary Islands) in April 2022, 4 months after the end of the eruptions of the Tajogaite volcano (Cumbre Vieja ridge). In contrast to herbs and grasses, most woody plants persisted and were already in full flower in areas with 10+ cm ash deposition. Remarkably, these persisting woody plants were almost exclusively endemics., This study was supported by the Global Change Ecology study program in the Elite Network of Bavaria. Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 4911832. Funded by the Open Access Publishing Fund of the University of Bayreuth.

Aim: Assessing the performances of different sampling approaches for documenting community diversity may help to identify optimal sampling efforts and strategies, and to enhance conservation and monitoring planning. Here, we used two data sets based on probabilistic and preferential sampling schemes of Italian forest vegetation to analyze the multifaceted performances of the two approaches across three major forest types at a large scale. Location: Italy. Methods: We pooled 804 probabilistic and 16,259 preferential forest plotsassamplesofvascularplantdiversity across the country. We balanced the two data sets in terms of sizes, plot size, geographical position, and vegetation types. For each of the two data sets, 1000 subsets of 201 random plots were compared by calculating the shared and exclusive indicator species, their overlap in the multivariate space, and the areas encompassed by spatially-constrained rarefaction curves. We then calculated an index of performance using the ratio between the additional and total information collected by each sampling approach. The performances were tested and evaluated across the three major forest types. Results: The probabilistic approach performed better in estimating species richness and diversity of species assemblages, but did not detect other components of the regional diversity, such as azonal forests. The preferential approach outperformed the probabilistic approach in detecting forest-specialist species and plant diversity hotspots. Conclusions: Using a novel workflow based on vegetation-plot exclusivities and commonalities, our study suggests probabilistic and preferential sampling approaches are to be used in combination for better conservation and monitor planning purposes to detect multiple aspects of plant community diversity. Our findings can assist the implementation of national conservation planning and large-scale monitoring of biodiversity.

Ecological processes are often spatially and temporally structured, potentially leading to autocorrelation either in environmental variables or species distribution data. Because of that, spatially-biased in-situ samples or predictors might affect the outcomes of ecological models used to infer the geographic distribution of species and diversity. There is a vast heterogeneity of methods and approaches to assess and measure spatial bias; this paper aims at addressing the spatial component of data-driven biases in species distribution modelling, and to propose potential solutions to explicitly test and account for them. Our major goal is not to propose methods to remove spatial bias from the modelling procedure, which would be impossible without proper knowledge of all the processes generating it, but rather to propose alternatives to explore and handle it. In particular, we propose and describe three main strategies that may provide a fair account of spatial bias, namely: (i) how to represent spatial bias; (ii) how to simulate null models based on virtual species for testing biogeographical and species distribution hypotheses; and (iii) how to make use of spatial bias - in particular related to sampling effort - as a leverage instead of a hindrance in species distribution modelling. We link these strategies with good practice in accounting for spatial bias in species distribution modelling.

Habitat richness, that is, the diversity of ecosystem types, is a complex, spatially explicit aspect of biodiversity, which is affected by bioclimatic, geographic, and anthropogenic variables. The distribution of habitat types is a key component for understanding broad‐scale biodiversity and for developing conservation strategies. We used data on the distribution of European Union (EU) habitats to answer the following questions: (i) how do bioclimatic, geographic, and anthropogenic variables affect habitat richness? (ii) Which of those factors is the most important? (iii) How do interactions among these variables influence habitat richness and which combinations produce the strongest interactions? The distribution maps of 222 terrestrial habitat types as defined by the Natura 2000 network were used to calculate habitat richness for the 10 km × 10 km EU grid map. We then investigated how environmental variables affect habitat richness, using generalized linear models, generalized additive models, and boosted regression trees. The main factors associated with habitat richness were geographic variables, with negative relationships observed for both latitude and longitude, and a positive relationship for terrain ruggedness. Bioclimatic variables played a secondary role, with habitat richness increasing slightly with annual mean temperature and overall annual precipitation. We also found an interaction between anthropogenic variables, with the combination of increased landscape fragmentation and increased population density strongly decreasing habitat richness. This is the first attempt to disentangle spatial patterns of habitat richness at the continental scale, as a key tool for protecting biodiversity. The number of European habitats is related to geography more than climate and human pressure, reflecting a major component of biogeographical patterns similar to the drivers observed at the species level. The interaction between anthropogenic variables highlights the need for coordinated, continental‐scale management plans for biodiversity conservation., We modeled EU habitat richness at continental scale as a function of geographic, climatic, and anthropogenic variables. We found geographical variables were by far the most strongly correlated with habitat richness, followed by climate. However, anthropogenic variables gained importance when considering their interactions, with important implications for conservation planning.

Forest fires are drivers of spatial patterns and temporal dynamics of vegetation and biodiversity. On the Canary Islands, large areas of pine forest exist, dominated by the endemic Canary Island pine, Pinus canariensis C. Sm. These mostly natural forests experience wildfires frequently. P. canariensis is well-adapted to such impacts and has the ability to re-sprout from both stems and branches. In recent decades, however, anthropogenically caused fires have increased, and climate change further enhances the likelihood of large forest fires. Through its dense, long needles, P. canariensis promotes cloud precipitation, which is an important ecosystem service for the freshwater supply of islands such as La Palma. Thus, it is important to understand the regeneration and vegetation dynamics of these ecosystems after fire. Here, we investigated species diversity patterns in the understory vegetation of P. canariensis forests after the large 2016 fire on the southern slopes of La Palma. We analyzed the effect of fire intensity, derived from Sentinel-2 NDVI differences, and of environmental variables, on species richness (alpha diversity) and compositional dissimilarity (beta diversity). We used redundancy analysis (dbRDA), Bray–Curtis dissimilarity, and variance partitioning for this analysis. Fire intensity accounted for a relatively small proportion of variation in alpha and beta diversity, while elevation was the most important predictor. Our results also reveal the important role of the endemic Lotus campylocladus ssp. hillebrandii (Christ) Sandral & D.D.Sokoloff for understory diversity after fire. Its dominance likely reduces the ability of other species to establish by taking up nutrients and water and by shading the ground. The mid-to long-term effects are unclear since Lotus is an important nitrogen fixer in P. canariensis forests and can reduce post-fire soil erosion on steep slopes.

Aim Biological invasions are likely determined by species dispersal strategies as well as environmental characteristics of a recipient region, especially climate and human impact. However, the contribution of climatic factors, human impact, and dispersal strategies in driving invasion processes is still controversial and not well embedded in the existing theoretical considerations. Here, we study how climate, species dispersal strategies, and human impact determine plant invasion processes on islands distributed in all major oceans in the context of directional ecological filtering. Location Six mountainous, tropical, and subtropical islands in three major oceans: Island of Hawai'i and Maui (Pacific), Tenerife and La Palma (Atlantic), and La Réunion and Socotra (Indian Ocean). Taxon Vascular Plants. Methods We recorded 360 non-native species in 218 plots along roadside elevational transects covering the major temperature, precipitation and human impact (i.e., road density) gradients of the islands. We collected dispersal strategies for a majority of the recorded species and calculated the environmental niche per species using a hypervolume approach. Results Non-native species’ generalism (i.e., mean community niche width) increased with precipitation, elevation and human impact but showed no relationship with temperature. Increasing precipitation led to environmental filtering of non-native species resulting in more generalist species under high precipitation conditions. We found no directional filtering for temperature but an optimum range of most species between 10 and 20°C. Niche widths of non-native species increased with the prevalence of certain dispersal strategies, particularly anemochory and anthropochory. Main conclusions Plant invasion on tropical and subtropical islands seems to be mainly driven by precipitation and human impact, while temperature seems to be of little importance. Furthermore, anemochory and anthropochory are dispersal strategies associated with large niche widths of non-native species. Our study allows a more detailed look at the mechanisms behind directional ecological filtering of non-native plant species in non-temperature-limited ecosystems., Journal of Biogeography, 48 (8), ISSN:0305-0270, ISSN:1365-2699

Positive plant-plant interactions are thought to drive vegetation patterns in harsh environments, such as semi-arid areas. According to the stress-gradient hypothesis (SGH), the role of positive interactions between species (facilitation) is expected to increase with harshness, predicting associated variation in species composition along environmental gradients. However, the relation between stress and facilitation along environmental gradients is debated. Furthermore, differentiating facilitative interactions from other underlying mechanisms, such as microtopographic heterogeneity, is not trivial. We analysed the spatial cooccurrence relationships of vascular plant species that form patchy vegetation in arid lapilli fields (tephra) from recent volcanic eruptions on La Palma, Canary Islands. We assume a harshness gradient negatively correlated with elevation because of more arid conditions at lower elevations where water availability is considered the most limiting resource. Based on the SGH we expect a greater degree of co-occurrence at lower elevations, as an outcome of facilitation is plants co-occurring in the same patch. We tested this at both the species and the individual plant level. We analysed the species composition of 1277 shrubby vegetation patches at 64 different sampling points, ranging from the coast to around 700 m a.s.l. Patch morphology and microtopographic heterogeneity variables were also measured, to account for their potential effects on the species composition of patches. We used generalized linear models and generalized mixed-effects models to analyse species richness, number of individuals in patches and percentage of patches with positive co-occurrences, and a pairwise co-occurrence analysis combined with a graphical network analysis to reveal positive links between 13 of the species. We found that the percentage of patches with positive co-occurrences increased at higher elevations, in contrast to the predictions of the SGH, but in accordance with a refined stress-gradient hypothesis for arid sites, in which characteristics of the interacting species are incorporated.

Forest fires are drivers of spatial patterns and temporal dynamics of vegetation and biodiversity. On the Canary Islands, large areas of pine forest exist, dominated by the endemic Canary Island pine, Pinus canariensis C. Sm. These mostly natural forests experience wildfires frequently. P. canariensis is well-adapted to such impacts and has the ability to re-sprout from both stems and branches. In recent decades, however, anthropogenically caused fires have increased, and climate change further enhances the likelihood of large forest fires. Through its dense, long needles, P. canariensis promotes cloud precipitation, which is an important ecosystem service for the freshwater supply of islands such as La Palma. Thus, it is important to understand the regeneration and vegetation dynamics of these ecosystems after fire. Here, we investigated species diversity patterns in the understory vegetation of P. canariensis forests after the large 2016 fire on the southern slopes of La Palma. We analyzed the effect of fire intensity, derived from Sentinel-2 NDVI differences, and of environmental variables, on species richness (alpha diversity) and compositional dissimilarity (beta diversity). We used redundancy analysis (dbRDA), Bray–Curtis dissimilarity, and variance partitioning for this analysis. Fire intensity accounted for a relatively small proportion of variation in alpha and beta diversity, while elevation was the most important predictor. Our results also reveal the important role of the endemic Lotus campylocladus ssp. hillebrandii (Christ) Sandral & D.D.Sokoloff for understory diversity after fire. Its dominance likely reduces the ability of other species to establish by taking up nutrients and water and by shading the ground. The mid- to long-term effects are unclear since Lotus is an important nitrogen fixer in P. canariensis forests and can reduce post-fire soil erosion on steep slopes.

The Canarian juniper woodland, dominated by Juniperus turbinata ssp. canariensis, is a priority habitat and is among the most endangered ecosystems of the European Union. Saplings of 12 species were planted between March 2006 and January 2008 within the Rural Park of Teno (Tenerife) during a LIFE reforestation project. To assess the replanting effectiveness, six 25 × 25 m permanent plots were established for monitoring plant conditions in 2014. We report the results of annual surveys up to 2019. We recorded vitality, phenology and size of 225 planted individuals belonging to eight different species. The vitality showed general positive trends, with a low 2018 decrease. Around 30% of surviving saplings displayed flowers or fruits in 2019. Juniperus turbinata ssp. canariensis and Olea cerasiformis presented a significant increment for all the growth traits, but only the juniper showed locally varied patterns of growth. We expect that the monitoring will contribute useful insights for other restoration projects for the endangered Canary endemic thermophilous woodland. El sabinar, comunidad dominada por Juniperus turbinata ssp. canariensis, constituye un hábitat prioritario de la Unión Europea. En el marco de un proyecto LIFE de reforestación entre marzo de 2006 y enero de 2008 fueron plantadas plántulas de 12 especies leñosas en el Parque Rural de Teno (Tenerife). Para comprobar el éxito de la plantación se establecieron en el año 2014 seis parcelas permanentes cuadradas de 25 m de lado en la zona reforestada. En este trabajo se describen los resultados del seguimiento anual llevado a cabo hasta 2019. Se registraron valores de vitalidad, fenología y tamaño de 225 individuos pertenecientes a ocho especies diferentes. La vitalidad presenta una tendencia positiva, con un pequeño bajón en 2018, mientras que el 30% de los individuos supervivientes ya producían flores o frutos en 2019. Juniperus turbinata ssp. canariensis y Olea cerasiformis presentaron un incremento significativo para todos los rasgos analizados, pero solo la sabina mostró patrones de creci-miento localmente variados. Esperamos que el seguimiento contribuya con conocimientos útiles para otros proyectos de restauración del amenazado bosque termófilo endémico canario.

Positive plant–plant interactions are thought to drive vegetation patterns in harsh environments, such as semi-arid areas. According to the stress-gradient hypothesis (SGH), the role of positive interactions between species (facilitation) is expected to increase with harshness, predicting associated variation in species composition along environmental gradients. However, the relation between stress and facilitation along environmental gradients is debated. Furthermore, differentiating facilitative interactions from other underlying mechanisms, such as microtopographic heterogeneity, is not trivial. We analysed the spatial co-occurrence relationships of vascular plant species that form patchy vegetation in arid lapilli fields (tephra) from recent volcanic eruptions on La Palma, Canary Islands. Assuming a harshness gradient negatively correlated with elevation because the lower elevations are more arid and water availability is considered the most limiting resource, and that an outcome of facilitation is plants co-occurring in the same patch, from the SGH we expected a greater degree of co-occurrence at lower elevation. We tested this at both the species and the individual plant level. We analysed the species composition of 1277 shrubby vegetation patches at 64 different sampling points, ranging from the coast to around 700 m a.s.l. Patch morphology and microtopographic heterogeneity variables were also measured, to account for their potential effects on the species composition of patches. We used generalized linear models and generalized mixed-effects models to analyse species richness, number of individuals in patches and percentage of patches with positive co-occurrences, and a pairwise co-occurrence analysis combined with a graphical network analysis to reveal positive links between 13 of the species. We found that the percentage of patches with positive co-occurrences increased at higher elevations, in contrast to the predictions of the SGH, but in accordance with a refined stress-gradient hypothesis for arid sites, in which characteristics of the interacting species are incorporated. publishedVersion

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. T. Biological invasions are a major global threat to biodiversity and often affect ecosystem services negatively. They are particularly problematic on oceanic islands where there are many narrow-ranged endemic species, and the biota may be very susceptible to invasion. Quantifying and mapping invasion processes are important steps for management and control but are challenging with the limited resources typically available and particularly difficult to implement on oceanic islands with very steep terrain. Remote sensing may provide an excellent solution in circumstances where the invading species can be reliably detected from imagery. We here develop a method to map the distribution of the alien chestnut (Castanea sativa Mill.) on the island of La Palma (Canary Islands, Spain), using freely available satellite images. On La Palma, the chestnut invasion threatens the iconic laurel forest, which has survived since the Tertiary period in the favourable climatic conditions of mountainous islands in the trade wind zone. We detect chestnut presence by taking advantage of the distinctive phenology of this alien tree, which retains its deciduousness while the native vegetation is evergreen. Using both Landsat 8 and Sentinel-2 (parallel analyses), we obtained images in two seasons (chestnuts leafless and in-leaf, respectively) and performed image regression to detect pixels changing from leafless to in-leaf chestnuts. We then applied supervised classification using Random Forest to map the present-day occurrence of the chestnut. Finally, we performed species distribution modelling to map the habitat suitability for chestnut on La Palma, to estimate which areas are prone to further invasion. Our results indicate that chestnuts occupy 1.2% of the total area of natural ecosystems on La Palma, with a further 12–17% representing suitable habitat that is not yet occupied. This enables targeted control measures with potential to successfully manage the invasion, given the relatively long generation time of the chestnut. Our method also enables research on the spread of the species since the earliest Landsat images.

© Pensoft Publishers. Background Biogeographical units are widely adopted in ecological research and nature conservation management, even though biogeographical regionalisation is still under scientific debate. The European Environment Agency provided an official map of the European Biogeographical Regions (EBRs), which contains the official boundaries used in the Habitats and Birds Directives. However, these boundaries bisect cells in the official EU 10 km x 10 km grid used for many purposes, including reporting species and habitat data, meaning that 6881 cells overlap two or more regions. Therefore, superimposing the EBRs vector map over the grid creates ambiguities in associating some cells with European Biogeographical Regions. New information To provide an operational tool to unambiguously define the boundaries of the eleven European Biogeographical Regions, we provide a specifically developed raster map of Grid-Based European Biogeographical Regions (GB-EBRs). In this new map, the borders of the EBRs are reshaped to coherently match the standard European 10 km x 10 km grid imposed for reporting tasks by Article 17 of the Habitats Directive and used for many other datasets. We assign each cell to the EBR with the largest area within the cell.

The growing interest in emerging environmental crisis has increased the level of public attention and the willingness to take part in participatory science projects, commonly defined with the term “Citizen Science”. This phenomenon can be recorded globally in many national contexts, with a prevalence in anglophone and more industrialized countries. In the biodiversity sector, the growing demand for public involvement has been declined in many different ways, with solutions aimed at providing cognitive and participatory tools. Among these, one of the best known is the BioBlitz: a 24-hour event held in a specific place with the aim of listing as many living species as possible. This work presents the data collected during the first two BioBlitzes organized by the Maremma Natural History Museum in 2013 and 2014. Both were made in the area of the San Felice Oasis, near the terminal part of the San Leopoldo ditch. During the BioBlitz, data collected attested the presence of 616 different taxonomic entities, of which 507 were identified at the level of species and 22 at the level of subspecies. The rest were identified at higher taxonomic levels. Eleven alien species, one endemic species, 33 species protected by national and international laws and / or directives and 9 species at risk of extinction were identified.

Protected areas (PAs) constitute major tools in nature conservation. In the European Union (EU), the Birds and Habitats Directives are the most important policies for conservation strategy, legally preserving Europe’s characteristic, rare, endemic and threatened biota. We used occurrence data for species listed in the directives’ Annexes to assess the uniqueness of major PAs in the EU (National Parks, Biosphere Reserves); this is important for preserving the EU’s focal species. We developed a novel, multifunctional approach to calculate different metrics of conservation value that represent different components of species diversity within the PAs, involving inventory diversity, deviation from the species–area relationship, species rarity and differentiation diversity. Applying it, we found that individual PAs frequently vary considerably in their scores on different components, which are often disconnected from PA size. PAs around the EU periphery, often containing few species, are key to conserving species that are rare in the EU. Because our analysis focuses on EU priority species and includes different components of diversity, it allows more appropriate estimation of conservation value inside PAs in context of the EU than recent, high-profile, global-level research. We offer tools to evaluate, and information to regulate, the representativeness, persistence and efficiency of PAs.

The article 17 of the 92/43/EEC Habitats Directive imposes to the Members States to produce periodic reports (every 6 years) on the conservation status of habitats and species at national level. In this context, in view of preparing the 4th National Report, the Italian National Institute for Environmental Protection and Research (ISPRA) drafted the national guidelines for habitats monitoring, focusing on data collection at site level. The intention of this paper is to provide an overview about the development, in Italy, on Habitat types monitoring methodologies, in particular detailing the current state-of-the-art for the parameter structure and functions, which is the most controversial among those required by the Habitats Directive for the assessment of conservation status. The paper concludes that, although habitat types monitoring programs could be carried out using individual species of fauna and/or flora, vegetation surveys represent the best choice as it allows to collect standardised and objective data, useful for the definition of more specific indicators, first of all the presence and abundance of typical species.

Aim: Species-area relationships (SARs) are fundamental scaling laws in ecology although their shape is still disputed. At larger areas power laws best represent SARs. Yet, it remained unclear whether SARs follow other shapes at finer spatial grains in continuous vegetation. We asked which function describes SARs best at small grains and explored how sampling methodology or the environment influence SAR shape. Location: Palaearctic grasslands and other non-forested habitats. Taxa: Vascular plants, bryophytes and lichens. Methods: We used the GrassPlot database, containing standardised vegetation-plot data from vascular plants, bryophytes, and lichens spanning a wide range of grassland types throughout the Palaearctic and including 2057 nested-plot series with at least seven grain sizes ranging from 1 cm2 to 1024 m². Using non-linear regression, we assessed the appropriateness of different SAR functions (power, power quadratic, power breakpoint, logarithmic, Michaelis-Menten). Based on AICc, we tested whether the ranking of functions differed among taxa, methodological settings, biomes or vegetation types. Results: The power function was the most suitable function across the studied taxa. The superiority of this function increased from lichens to bryophytes to vascular plants to all three taxa together. The sampling method was highly influential as rooted-presence sampling decreased the performance of the power function. By contrast, biome and vegetation type had practically no influence on the superiority of the power law. Main conclusions: We conclude that SARs of sessile organisms at smaller spatial grains are best approximated by power functions. This coincides with several other comprehensive studies of SARs at different grain sizes and for different taxa, thus supporting the general appropriateness of power functions for modelling species diversity over many grain sizes. The poor performance of the Michaelis-Menten function demonstrates that richness within plant communities generally does not approach any saturation, thus calling to abandon the concept of minimal area.

Sacred Natural Sites are relevant for biodiversity conservation, as in the case of forest sites that, across centuries, developed old growth structures and are now crucial for the conservation of epiphytic lichens and other specialized forest organisms. In this study, we investigated the epiphytic lichen flora of a small forest patch included in the Majella National Park (Abruzzo), whose old growth features and naturalness reflect its long lasting spiritual role that perfectly fits with the concept of Sacred Natural Site. Results revealed that the "Bosco di Sant'Antonio" hosts a rich and interesting epiphytic lichen flora, thus indicating the potential of this Sacred Natural Site for lichen conservation. Fifty-six species were found including two species newly recorded in Abruzzo, two red-listed species, and the sensitive species Lobaria pulmonaria. This study corroborates the hypothesis that sacred forest sites are relevant for the conservation of specialized epiphytic lichens. In particular, in the Italian forest landscape where old-growth stands are practically absent, sacred forest sites may provide unique old-growth structures and buffer anthropogenic disturbance.

The diversity of alpine grassland species and their functional traits constitute alpine ecosystem functioning and services that support human-wellbeing. However, alpine grassland diversity is threatened by land use and climate change. Field surveys and monitoring are necessary to understand and preserve such endangered ecosystems. Here we describe data on abundances (percentage cover) of 247 alpine plant species (including mosses and lichens) inside nine 20 m by 20 m plots that were subdivided into 2 m by 2 m subplots. The nine plots are located in Gran Paradiso National Park, Italy. They cover three distinct alpine vegetation subtypes (‘pure’ natural grassland, sparsely vegetated ‘rocky’ grassland, and wetland) in each of three valleys (Bardoney, Colle de Nivolet and Levionaz) between 2200 and 2700 m a.s.l., i.e. above the treeline. The vegetation survey was conducted in 2015 at the peak of vegetation development during August. The dataset is provided as supplementary material and associated with the research article “Optimizing sampling effort and information content of biodiversity surveys: a case study of alpine grassland” [1]. See [1] for data interpretation. Keywords: Alpine grassland, Species diversity, Plot data, Cover, Abundance, Vegetation survey, Vegetation monitoring

Aim:Species-area relationships (SARs) are probably the most fundamental and most studied scaling law in ecology. Still there is on-going dispute on their shape. At coarse grain sizes, several analyses of island SARs have demonstrated that the power law overall performs best. Yet, at fine spatial grains in continuous vegetation, it was unresolved whether SARs follow a power-law, logarithmic or other function. We thus asked which function type is most suitable in such situations and whether the prevalence of functions or their parameters are related to ecological or methodological settings. Location: Grasslands of the Palaearctic biogeographic realm. Methods: We used the new GrassPlot database, containing standardised vegetation-plot data from a wide range of grassland types throughout the Palaearctic, including nearly 5,000 nested-plot series with at least four grain sizes. Besides vascular plants, often also terricolous bryophytes and lichens were sampled, allowing to evaluate differences in scaling laws between these ecologically contrasting taxa. Using non-linear regression modelling, we assessed the appropriateness of a set of proposed SAR-function types and evaluated their parameters. We then tested whether the relative ranking (based on AICc) of function types or their parameters differed between taxonomic groups, geographic regions or grassland types. Results: Our results demonstrate that for the studied fine grains the power law was on 39average the most suitable function. Its slope parameter (z) was significantly larger for lichens than for other taxa, with little difference between regions and grassland types. Main conclusions: We conclude that SARs at any spatial scale are best approximated with power laws. Together with the established range of typical z-values this allows making richness data sampled on differently sized plots comparable by interpolation, thus providing an important tool for the analysis of the heterogeneous data stored in big continental to global vegetation-plot databases such as EVA and sPlot.

Spatially-explicit dataset of plant species occurrences collected in the Province of Siena (Central Italy) is analysed, with the aim of investigating a) the relative role of environmental factors in shaping spatial patterns of plant species richness, and b) how the spatial scale at which predictors have been sampled determines the explicative power of species richness models. The optimal spatial resolution of analysis was evaluated with respect to the total deviance explained by models, using a set of environmental and remotely sensed derived predictors calculated at different spatial scales. Results confirm the hypothesis that the predictive power of landscape structure is influenced by the spatial scale at which predictor variables have been sampled. Furthermore, the relevance of identifying a proper geographical scale of investigation, hence minimizing the redundancy in the predictor variables and maximising the explanatory power of the single groups of predictor variables, is highlighted as well.

Understanding patterns and drivers of phytodiversity as well as ecological scaling laws and assembly rules constitute core interests both of vegetation ecologists and macroecologists. To enhance our understanding of these issues, we compiled the new “Database of Scale-Dependent Phytodiversity Patterns in Palaearctic Grasslands” (GrassPlot; GIVD ID EU-00-003) within the framework of the Eurasian Dry Grassland Group (EDGG). GrassPlot contains high-quality plot observations (relevés) of eight standard grain sizes (0.0001; 0.001 … 1000 m²) as well as nested-plot series with at least four different grain sizes. The scope of GrassPlot are the grasslands as well as other herb- or cryptogam-dominated terrestrial and semi-terrestrial vegetation types from the whole Palaearctic biogeographic realm (Europe, North Africa, West, Central and North Asia).

Elevational gradients in high mountain ranges are particularly suitable to study and understand pat- terns and drivers of plant community diversity and composition, yet there are only few studies that explicitly addressed this topic for the European Alps. Here we analysed an elevational gradient in grasslands of the Gran Paradiso National Park (NW Italy) from c. 1,700 to 3,100 m a.s.l. We recorded vascular plant species composition in 13 100-m² plots, each with two series of nested subplots from 0.0001 to 10 m², as well as a set of environmental parameters (topography, soil). Beta-diversity was assessed via the z-values of power-law species-area relationships, both across all plot sizes and from one plot size to the next bigger one. Diversity-environment relationships were assessed with multi- model inference based on Akaike information criterion (AIC), while scale dependence in z-values across plot sizes was analysed with an ANOVA. Life forms and three major functional traits (specific leaf area = SLA, canopy height, seed mass) were derived from trait databases to calculate fractions of life forms and community-weighted means for the metric traits. Species richness on 100 m² ranged from 17 to 65, with a mean of 43.5. The z-values were within a typical range known for European grasslands (mean: 0.227), with non-significant scale dependence. The importance of environmental factors for richness changed across grain sizes, with inclination (positive effect), mean soil depth and soil skeleton content (both: negative effect) being most influential at grain sizes of 0.0001–1 m². By contrast, soil pH was most important (with a unimodal relationship) for 10 and 100 m². After account- ing for the other environmental factors, elevation showed a moderate unimodal relationship only for the two largest grain sizes. By contrast, functional composition showed strong and mostly significant rela- tionships with elevation: hemicryptophytes and geophytes became rarer and chamaephytes more fre- quent, while community-weighted means of SLA, canopy height and seed mass decreased. Our findings highlight the scale dependence of biodiversity patterns, thus pointing to the need of multi-scale sampling to reach comprehensive understanding. Further, we could provide one of the first documentations of biodiversity and functional composition along an elevational gradient in the Alps, some in agreement with expectations, others not. This suggests that more extensive studies with a similar design in this and other regions of the Alps could be a valuable contribution to the understanding of how environmental factors drive components of biodiversity as well a functional community assembly.

Anticipating species distributions in space and time is necessary for effective biodiversity conservation and for prioritising management interventions. This is especially true when considering invasive species. In such a case, anticipating their spread is important to effectively plan management actions. However, considering uncertainty in the output of species distribution models is critical for correctly interpreting results and avoiding inappropriate decision-making. In particular, when dealing with species inventories, the bias resulting from sampling effort may lead to an over- or under-estimation of the local density of occurrences of a species. In this paper we propose an innovative method to i) map sampling effort bias using cartogram models and ii) explicitly consider such uncertainty in the modeling procedure under a Bayesian framework, which allows the integration of multilevel input data with prior information to improve the anticipation species distributions.

1. Species-abundance distributions (SADs) are a convenient and common method for describing ecological communities. Despite their long history and the cornucopia of theoretical models, which have been suggested to describe them, no agreement has been reached as to which models are best. 2. This lack of agreement is in part owing to the inherent differences in the abundance measure used. Discrete measures such as density and point quadrat cover produce a distinct veil line (positive skewness) when compared to continuous measures such as biomass or basal area. We compared two different sets of discrete and continuous abundance measures commonly used to estimate plant abundance, (i) cover (estimated from point quadrats) vs. biomass for 35 quadrats in garigue vegetation on serpentine soil in Tuscany, Italy; and (ii) density vs. basal area for the 2005 50 ha BCI (Panama) tree data. We used marginal plots (ordinary scatter plots with a dotplot of each variable along its own axis) to compare the shape of the SADbased on the two abundance measures. 3. The average of all 35 garigue plots gave a reasonably consistent description of the data. In contrast, when all 35 plots were concatenated, or when an individual plot was investigated, the discrete cover marginal plot, but not the continuous biomass plot, was truncated. The discrete density marginal plot, but not the continuous basal area plot was also truncated. 4. We highlighted the substantial effect that the species-abundance measure selected has on the shape of the SADby comparing measures of skewness and kurtosis. This suggests that communities sampled using different abundance methods may fit different theoretical models best, not because they are fundamentally different but because the abundance measure is fundamentally different. Averaging over all the quadrats produced a better correspondence between the two abundance methods. Aside from the theoretical aspects of model fitting, our results clearly show that comparisons of communities or meta-analyses using SADs based on different measures of abundance should be treated with caution.

Plant biodiversity of beech forests in central-northern Italy: a methodological approach for conservation pur- poses. Forests are reckoned essentials as biodiversity reservoirs and carbon sinks. Current threats to forest ecosystems (e.g., climate changes, habitat loss and fragmentation, management changes) call for monitoring their biodiversity and preserving their ecological functions. In this study, we characterized plants diversity of five beech forests located in central and north Apennines mountain chain, using results by a probabilistic sampling. In order to achieve our goals, we have considered species richness and abundance, taxonomic di- stinctness and species composition, using both old and new analytical approaches. Results have shown how: (1) the forest type dominated by Fagus sylvatica is characterized by high complexity, with marked composi- tional, structural and biodiversity differences; (2) beech forests of Pigelleto di Piancastagnaio and Valle della Corte show the highest plants diversity values. The ecological characteristics of these areas, which sustain high diversity values, are unique and of great conservation interest; (3) the use of species richness as the only diversity measure have not allowed an efficient differentiation between studied areas. Indeed, the use of dif- ferent indexes and analytical methods is required to detect multiple characteristics of biological diversity, as well as to carry out efficient biodiversity surveys aimed to develop optimal conservation strategies. In the fu- ture, we plan to apply the sampling methodology and the analytical approach used in this paper to characte- rize plants diversity of similar forest types.

We discuss the usefulness of the concept of Potential Natural Vegetation (PNV), which describes the expected state of mature vegetation in the absence of human intervention. We argue that it is impossible to model PNV because of (i) the methodological problems associated to its definition and (ii) the issues related to the ecosystems dynamics.We conclude that the approach to characterizing PNV is unrealistic and provides scenarios with limited predictive power. In places with a long-term human history, interpretations of PNV need to be very cautious, and explicit acknowledgement made of the limitations inherent in available data.

Additive partition of diversity as standard for the selection of protected areas: the natural reserves network of the Siena province (Italy). Estimating the effects of the spatial components on species diversity represents an important step to establish the conservation “capacity” in a network of protected areas. A clear evaluation on how α, β, and γ diversity are partitioned among and within spatial (and temporal) scales can help us to drive managing decisions and provide methods for monitoring species diversity. Moving from these concepts, a probabilistic sample was applied here: (1) for quantifying plant species diversity at different spatial scales within the network of protected areas existing in the Siena Province (Central Italy); and (2) to evaluate the effects on the species diversity of the whole network due to the addition of two new protected areas (Ripa d’Orcia and Bogatto). Focusing on both common species and those defined as “focal” (included in regional, national or continental “red” lists), our results indicated that species richness of the protected areas differed each other independently from the sampling efforts. Diversity partitioning indicated that most of the diversity within the network is due to larger-scale β-diversity, i.e., the differences in species composition among reserves. Moreover, total β-diversity was decomposed into two components: βarea (due to the differences in area among reserves) and βreplacement (due to the compositional differences across protected areas). βarea was particularly important for all species, while βreplacement was the most important factor for the set of focal species. Noteworthy, the analyzed variation in diversity components due to the inclusion of the two new natural reserves into the network (Ripa d’Orcia and Bogatto) resulted in a proportional increase in βArea for the whole network, and, on the other hand, in a reduction for βreplacement diversity component. Based on these quantitative results, criteria for the selection and the inclusion of protected areas in existing networks of natural reserves (such as the Natura 2000 Network) can be achieved.

La β-diversità è definita come la complementarietà tra siti in termini di composizione specifica e gioca un ruolo fondamentale nella gestione e nella conservazione della biodiversità, dal momento che permette l’individuazione di gradienti ambientali che agiscono funzionalmente nel determinare la variazione della composizione specifica. Da un punto di vista ecologico, il decadimento della β-similarità all’aumentare della distanza (distance decay) deriva da: (i) una diminuzione della similarità ambientale con l’aumentare della distanza, che crea una competizione tra le specie con differenti adattamenti fisiologici (modello di differenziazione di nicchia, niche difference model); (ii) barriere spaziali che creano isolamento tra habitat influenzando il movimento specifico e genico. Ad oggi numerosi sforzi sono stati fatti per dimostrare l’effetto della distanza spaziale sulla similarità in termini di specie (β-similarità). Tuttavia, pochi studi sono stati effettuati a scala locale, i.e. a livello di comunità vegetale. Lo scopo del presente studio è quello di testare l’ipotesi del decadimento della β-similarità a scala locale (plot di 10x10 m inseriti nell’ambito del progetto MoBiSIC, Monitoraggio della Biodiversità nei SIC della Provincia di Siena) considerando: (i) la distanza spaziale tra siti; (ii) la distanza ecologica, misurata come distanza euclidea in spazi vettoriali definiti da variabili ecologiche (quota, esposizione, pendenza, assolazione, valori spettrali derivati da un’immagine Landsat ETM+, considerando sia l’intero dataset multispettrale che il vicino infrarosso, banda 4). I tassi di decadimento della β-similarità a differenti soglie (τ) sono stati quantificati tramite regressioni quantili basate su modelli esponenziali, focalizzando l’attenzione sui principali fattori che ne influenzano l’andamento.

Each year, the Chief Editors of the Journal of Vegetation Science choose one of the papers nominated by Coordinating Editors and Referees, for the Editors´ Award for their quality, novelty or clarity in approaching a topic in vegetation science. There is no financial or other reward, just glory for the authors! For this year, there were eight papers nominated.The paper selected for the Editors´ Award was that by Carlyle & Fraser (2006). This paper reports an experiment, performed under controlled greenhouse conditions, to test the Competitive Response (CR) strategy model in 19 species typical of wet meadows in Northeast Ohio, USA. Each species was placed into one of three strategies based on variation in the CR strategy of juvenile plants growing under a canopy: (1) persist; (2) escape; (3) forage. The three possible strategies were tested with well-planned experiments and then checked for correlations with classic plant traits such as seed size or plant biomass. Fil: Chiarucci, Alessandro. Universita Degli Studi Di Siena; Italia Fil: Collins, Beverly. Western Carolina University; Estados Unidos Fil: Díaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: White, Peter S.. University of North Carolina; Estados Unidos

Restoration ecology is becoming an important part of applied science, especially because of the pressing need to restore to a pristine state, or to another functionally stable state, many sites that have been degraded by human pressure, pollution, or management. In almost all terrestrial habitats and in many aquatic ones ecological restoration passes through some process of vegetation restoration, since vegetation is vital for ecosystem structure and function. Fittingly, vegetation restoration was a theme of Applied Vegetation Science in 2006. The two issues included 34 papers and a total of 316 pages. The first issue included many papers on the theme Conservation and restoration of the Pinus palustris ecosystem, while the second was fully dedicated to the theme Fens and floodplains of the temperate zone: Present status, threats, conservation and restoration. Restoration of natural vegetation was the aim of most of these papers, using a variety of approaches and methods for the recruitment of structurally important plant species in different ecosystems. Fil: Chiarucci, Alessandro. Universita Degli Studi Di Siena; Italia Fil: Collins, Beverly. Western Carolina University; Estados Unidos Fil: Díaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: White, Peter S.. University of North Carolina; Estados Unidos Fil: Wilson, J. Bastow. University of Otago; Nueva Zelanda

Disturbance ecology has become an integral part of vegetation science over the past 25 years. Understanding human disturbances and human effects on natural disturbance regimes is a key to establishing restoration goals and initiating restoration projects. However, as this literature has developed, the picture has become both more interesting and more complex: Disturbances interact; each disturbance leaves behind a patch work of effects; and particular disturbances have different effects in different seasons and from one year to another. In addition, different species respond differently to the same disturbance. We are left with questions such as: Can we predict vegetation response to fire in restoration projects? Clearly, we must understand the mechanisms of species response to disturbance in order to answer these questions and achieve a predictive science. The Editor’s Award for 2005 goes to a paper that treats interactions of fire and mowing in a long-term experiment: “Long-term composition responses of a South African mesic grassland to burning and mowing” by Fynn, Morris & Edwards (2005). The authors report on the 50+ year Ukulinga burning and mowing experiment at the research farm of the University of KwaZuluNatal in South Africa. This experiment, initiated in 1950, is remarkable: three replicates in a randomized split-plot, full-factorial design with four whole-plot and 11 subplot treatments. Mowing treatments included none to early season, late season, and early-plus-late season. Fire treatments were none, annual, biennial, and triannual in winter, spring or autumn. In sum, plot disturbance ranged from protection over 50 years to twice summer mowing plus mowing or fire in the dormant season each year. The authors found that grasses responded to type of disturbance and fire frequency, but forbs were less sensitive to disturbance type. The disturbance combinations controlled vegetation structure and composition, with some combinations producing a short-grass Disturbance, seeds, restoration, and the importance of experiments and long-term observations: the Editors’ Award for 2005 White, Peter S.1*; Chiarucci, Alessandro2; Collins, Beverly3 & Díaz, Sandra4 1Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA; 2Dipartimento di Scienze Ambientali ‘G. Sarfatti’, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy; 3Savannah River Ecology Lab, P.O. Drawer E, Aiken, SC 29802, USA; 4Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, Casilla de Correo, RA-5000 Córdoba, Argentina; *Corresponding author; E-mail peter.white@unc.edu community and others a tall-grass community. Tillering strategy (below or above ground) for grasses and habit (erect or creeping) for forbs explained many responses and are a means to predict differing responses of grasses and herbs and different responses of species within each group to disturbance combinations. The conclusion of the study suggests that the highest diversity and greatest number of species (as well as benefits for wildlife species) can be achieved by applying results at the landscape scale to create patches of diverse structures from simple combinations of disturbance type and season. The authors also found transient responses and compensatory changes among species, thus demonstrating the importance of long-term and experimental research. Fil: White, Peter S.. University of North Carolina; Estados Unidos Fil: Chiarucci, Alessandro. Universita Degli Studi Di Siena; Italia Fil: Collins, Beverly. University of Georgia. Savannah River Ecology Laboratory; Estados Unidos Fil: Díaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina