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Context: A long history of human colonisation has profoundly altered Mediterranean coastal dunes, as well as their capacity of providing ecosystem services important for human well-being. The provisioning of these services depends on the integrity of the dune system, which is formed and maintained by coastal plant communities. Analysing the drivers of plant diversity is thus crucial for preserving Mediterranean coastal ecosystems. Objectives: We investigated the influence of natural factors, anthropogenic activities and shoreline dynamism on different facets of plant diversity, i.e. species richness and the proportion of typical and ruderal species. Moreover, we examined whether natural and anthropogenic factors act as direct or rather indirect drivers of the loss of dune plant diversity. Methods: Using 20 cm resolution orthophotos, we mapped a wide Mediterranean coastal landscape and obtained a set of variables describing the distribution, abundance and size of natural (coastal dune habitats) and anthropogenic (urban areas and tourism facilities) patches. From the orthophotos, we also quantified the shoreline dynamism (coastal erosion and accretion) occurred in the area over a 10-year period. We then analysed how dune plant species richness, as well as the proportion of typical and ruderal species, related to the landscape variables and shoreline dynamism. Also, using piecewise structural equation modelling, we investigated the complex interplay between landscape variables and shoreline dynamism in shaping coastal plant diversity patterns. Results: When focusing on plant species richness, we found no evidence of a negative effect of anthropogenic activities (urbanisation and tourism) on the diversity of coastal vegetation. However, analysing typical and ruderal plant species revealed that the latter were favoured under human-related disturbance, while typical species of the foredune decreased in areas subject to high anthropogenic pressure. Results of the structural equation models highlighted that shoreline dynamism indirectly affected dune plant diversity through its influence on the landscape configuration. Conclusions: Our results indicate that (i) looking only at plant species richness can lead to underestimating the impact of anthropogenic activities on coastal dune vegetation; and (ii) that human-related activities change the composition of dune vegetation, eventually promoting the establishment of ruderal species. Finally, results show that coastal erosion acts as an indirect driver of plant diversity loss. [ABSTRACT FROM AUTHOR]

In this study, taking as an example the species-rich Nardus stricta grasslands (habitat 6230*) within the Natura 2000 network of the Lombardy region (northern Italy, central southern Alps), we evaluated i) whether the spatial distribution of the habitat 6230* corresponded to essential features for its identification, and ii) whether a broad habitat interpretation could affect its regional conservation status assessment.We analysed the spatial distribution of habitat 6230* regarding the elevation, geological substrate, forest treeline, land use types and other habitat types. Using the regional database of habitat relevés, we calculated the threshold values of conservation status for a range of indicators of structure, functions and future prospects. To this end, we used a subset of relevés of the subalpine sub-type of habitat 6230*, as it corresponds to plant communities where habitat interpretation can easily be extended beyond its definition.The mapped distribution of habitat 6230* did not entirely match the essential features required for its identification. Some polygons were located at the ecological extremes of habitat 6230*, on carbonate substrates and in the alpine belt. In those conditions, the habitat showed an Unfavourable-bad (U2) conservation status, decreasing species richness and typical species dominance and frequency. Our findings highlighted that plant communities representing ecological extremes of the habitat type 6230* should no longer be referred to the same habitat type.The proposed indicators can help identify habitat sub-types more conducive to successful restoration measures, thereby ensuring favourable conservation status. In turn, this guarantees sustainable agricultural land use, which simultaneously promotes biodiversity and high-quality food products. Furthermore, the procedure could be extended to other habitat types for early identification of priority monitoring areas, especially when their interpretation has gone beyond their definition, with little consideration given to the consequences on the regional conservation status assessments.

Vegetation is often classified through phytosociology, which defines floristically and ecologically coherent units identified by diagnostic species. Since species- and community-environment relations are regulated by plant functional traits, it is likely that phytosociology has a strong functional underpinning, although the past and current phytosociology does not explicitly tackle this issue. Here we provide an analysis of functional traits of 221 woody species from Northern Italy, diagnostic of 21 European woody vegetation classes (including alien dominated ones). We assessed whether the functional space occupied by selected species corresponds to the physiognomy and ecology of the vegetation they represent, and whether this could help to evaluate major threats, such as invasion by alien species. For each species we collected from Authors' datasets leaf trait data (leaf area, specific leaf area, leaf dry matter content, carbon to nitrogen ratio, leaf nitrogen content) and whole plant (plant height, seed mass) traits, and calculated Competitor, Stress-tolerant, Ruderal (CSR) scores. We identified the multidimensional functional trait space of diagnostic species and clustered classes according to their scores in the functional space, to check whether their physiognomy was coherently represented and mirrored in the CSR space. Lastly, we tested for differences between native and neophyte species and their overlap with classes. Diagnostic species mirrored the global spectrum of plant form and function, and classes showed a functional pattern coherent with their physiognomy and ecology. Evergreen dominated classes showed a similar convergence toward conservative characteristics and the stress-tolerant strategy, as opposed to deciduous forest classes that showed a tendency toward the competitive strategy. None of the classes showed a marked ruderal strategy, thus abiotic stress and biotic competition are the main ecological drivers affecting woody vegetation. Neophyte woody species exhibited relatively more competitive strategies compared to natives, and their invasion could be facilitated in resource-limited or mildly disturbed environments, should climate warming or increased nutrient availability occur. We demonstrated that plant traits and CSR strategies of woody diagnostic species reliably indicate the structure and functions of the phytosociological classes they represent, opening the way to the development of a "functional phytosociology". [ABSTRACT FROM AUTHOR]

Protected areas are recognized as a crucial tool to mitigate ongoing trends of biodiversity loss. The effect of different levels of protection and their subsequent conservation efficiency remains, however, largely unexplored. To fill this gap, we present here an integrated approach that combines taxonomic analysis based on typical species to evaluate habitat quality and functional analysis based on plant traits to define habitat structure and functions. We focused on shrubland habitats across levels of protection in two different biogeographical areas. We found that habitat quality does not change linearly with levels of protection. Furthermore, the increase in habitat quality is characterized by a homogenization of habitat structure and functions, mostly driven by an increase in typical species. Our study suggests the level of protection afforded by protected areas is not necessarily indicative of their quality. A combined taxonomic and functional approach in protected areas can offer a thorough appraisal of habitat quality. • We assessed habitat quality in protected areas (PAs). • We tested it using typical species and functional traits. • We found different results in two biogeographically contrasting study areas. • Protection level of PAs is not a good predictor for habitat quality. • Combination of typical species and plant traits is recommended for PAs appraisal. [ABSTRACT FROM AUTHOR]

Habitat degradation and fragmentation are recognized as major causes of biodiversity loss, and effective management to conserve habitats is highly dependent on our ability to assess their conservation status. In this study we introduce a new index (VCS, for vegetation conservation status) to assess the conservation status of plant communities, which reflect the identity of habitat types. The VCS index is based on the same probabilistic approach than the classical Simpson’s diversity index, but uses the concept of species pools to integrate the influence of ‘typical’ and ‘non-typical’ species on habitat conservation status. In addition to the effect of species identity, this index also allows the detection of change in conservation status because of variation in species-abundance distribution. As an example we applied the VCS index to two heathland habitats in French Brittany and we compared the values provided by the index to qualitative assessments by heathland experts. We also compared the performance of the VCS index against three other indices: species richness, species diversity and a more recent index of ‘favourable conservation status’. Among the four indices tested, the VCS index was the most effective in assessing the vegetation conservation status when compared against qualitative assessment by heathland experts. Moreover the VCS index, coupled with variance partitioning methods, allowed to quantify the contribution of expected causes of habitat degradation. This study demonstrates that the use of habitat-specific species pools to distinguish between typical and non-typical species, as well as the consideration of species abundances, are critical for an accurate assessment of the vegetation conservation status. The VCS index should therefore be a valuable tool for both managers and researchers involved in habitat conservation.

Questions How can conservation status of rich fen and alkaline spring areas be assessed most cost-effectively based on existing monitoring data? What is the precision and accuracy of available indicators? Location Rich fen and alkaline spring areas in Denmark. Methods Potential indicators of conservation status were evaluated based on: accuracy, measured as the ability to predict the number of typical species in monitoring plots; precision, measured as variation over years of indicators in repeated plots; and cost of obtaining data for the indicator. Indicators were derived using data from the Danish National Monitoring and Assessment Programme for the Aquatic and Terrestrial Environment from 2000 to 2009. Indicators included biotic indices derived from species lists, abiotic measurements of p H and nutrients and structural measurements of vegetation height and tree cover. Results The majority of indicators showed a significant correlation with the number of typical species. Floristic indicators, especially based on Ellenberg nutrient values, showed superior correlation and were furthermore very stable over years. Structural indicators were generally accurate, but were highly imprecise with high between-year variation. Among the abiotic indicators, p H and soil P were inaccurate, whereas tissue N content and nitrate in water were accurate but with low precision. When balancing efficiency of indicators with monitoring costs, laboratory analyses stand out as expensive compared to recording of a species list, the latter providing up to five valuable indicators. Conclusions Floristic indicators derived from Ellenberg values, and especially those related to nutrient availability, are cost-effective indicators of conservation status. The method is applicable to all regions where Ellenberg indicator values have been calibrated to fit local conditions. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) play an important role in the formation of ozone. The concentrations of VOCs in the Jinnan District of Tianjin were monitored by the Syntech Spectras GC955 online monitoring system, and the ozone generation potential of VOCs was calculated by the maximum incremental activity factor. The results showed that the total concentration of VOCs in the Jinnan District was (32.33±23.77) μg·m -3 , in which the mass concentration of alkane was the highest, and propylene, ethylene and toluene had the highest mass concentration. During the observation period, the ozone formation potential (OFP) of TVOC was 107.81 μg·m -3 , and the contribution of alkenes to OFP was the largest, which was 55.80%. Ethylene, isoprene, and toluene accounted for the first three places of OFP contribution rate. The backward trajectory analysis showed that TVOC and its OFPs were different under different trajectories. The estimation of VOCs/NO x volume fraction ratio showed that O 3 formation was sensitive to VOCs, which showed that atmospheric photochemical pollution has a considerable degree of regional characteristics. The concentration ratio of ethylbenzene/ m,p -xylene, and ethane/acetylene can be used to measure the progress of atmospheric chemical reaction and photochemical age in the air mass, which was proved by the aging process of VOC.

Based on the online measurements of VOCs of high pollution process at the university site in winter, VOCs' characteristics and species at different levels of haze pollution were analyzed. Fifty-five VOCs were detected during sampling. ∑ 55 VOCs concentrations ranged between 25.5×10 -9 -1320.3×10 -9 (avg±SD,240×10 -9 ±181×10 -9 ). Toluene and xylene were the major pollutants during high pollution process, the concentrations of which were higher than those of industrial area. The university site shared a similar VOC composition with that of industrial area, which suggested that it might be influenced by the surrounding industries. VOCs species exhibited high concentrations in nighttime while low concentrations in daytime. The ozone concentrations were on the contrary. Aromatic hydrocarbons were predominant with a high percentage of contribution (70.0%) to OFP (ozone formation potential). Alkenes and alkynes were the second highest group (16.7%). The OFP of VOCs was 2078.2×10 -9 under the west-south wind direction, about 4 times higher than the value under other wind directions (505.8×10 -9 ). Aromatic hydrocarbons exhibited a predominant contribution to OFP at different levels of haze pollution in this area, among which, Toluene and xylene contributed more than 50% to OFP. The newest version of EPA PMF model was used to identify the major source of VOCs and evaluate their contributions. Gasoline sources and vehicle exhaust, refinery and petroleum products, solvent use and organic synthetic materials were the identified VOC sources in the study area, contributing 33.1%, 31.5%, 30.5%, and 4.9%, respectively to the ∑ 55 VOCs concentrations.