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Although intended to control pests, pesticides affect a phylogenetically diverse range of non-target species contributing to global biodiversity declines1–7. However, the magnitude of this risk is only partly understood. Here, we show that pesticides negatively affect non-target organisms across the tree of life. We analyzed 26,096 effect sizes from 1,705 studies reporting effects of insecticides, fungicides and herbicides on growth, reproduction, behaviour, and other biomarkers of non-target terrestrial and aquatic taxa. Pesticides negatively affected invertebrate and vertebrate animals, seed and spore-producing plants, as well as bacteria and fungi. Pesticides formulated to target a particular taxon negatively affected phylogenetically distant groups, e.g. insecticidal neonicotinoids impacted amphibians, fish, mammals and monocotyledonous plants. The effects were evident for field-realistic exposures, were more pronounced in temperate than tropical regions, and were consistent in magnitude for exposure in aquatic and terrestrial environments. The detection of strong detrimental effects of pesticides across a wide range of non-target organisms questions current regulatory practices. Adoption of sustainable management practices (e.g. agricultural ecological intensification, integrated pest management, and non-pesticide control) may help balance food security alongside reducing dependencies on pesticide with their associated risks to nature.

Control of crop pests by shifting host plant availability and natural enemy activity at landscape scales has great potential to enhance the sustainability of agriculture. However, mainstreaming natural pest control requires improved understanding of how its benefits can be realized across a variety of agroecological contexts. Empirical studies suggest significant but highly variable responses of natural pest control to land-use change. Current ecological models are either too specific to provide insight across agroecosystems or too generic to guide management with actionable predictions. We suggest obtaining the full benefit of available empirical, theoretical, and methodological knowledge by combining trait-mediated understanding from correlative studies with the explicit representation of causal relationships achieved by mechanistic modeling. To link these frameworks, we adapt the concept of archetypes, or context-specific generalizations, from sustainability science. Similar responses of natural pest control to land-use gradients across cases that share key attributes, such as functional traits of focal organisms, indicate general processes that drive system behavior in a context-sensitive manner. Based on such observations of natural pest control, a systematic definition of archetypes can provide the basis for mechanistic models of intermediate generality that cover all major agroecosystems worldwide. Example applications demonstrate the potential for upscaling understanding and improving predictions of natural pest control, based on knowledge transfer and scientific synthesis. A broader application of this mechanistic archetype approach promises to enhance ecology's contribution to natural resource management across diverse regions and social-ecological contexts. ANR; BMBF; FORMAS; FWF; MINECO; NWO; PT-DLR; Helmholtz-Zentrum fur Umweltforschung; iDiv - German Research Foundation [DFG-FZT 118, 202548816]; Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS); SLU Centre for Biological Control; Strategic research area Biodiversity and Ecosystem services in a Changing Climate (BECC); US Dept. of Agriculture, National Institute of Food and Agriculture (NIFA) [2020-67021-32477]; Volkswagen Foundation [A118199] Published version 2013-2014 BiodivERsA/FACCE-JPI joint call for research proposals (project ECODEAL), with the national funders ANR, BMBF, FORMAS, FWF, MINECO, NWO and PT-DLR; Helmholtz-Zentrum fur Umweltforschung; iDiv, funded by the German Research Foundation, Grant/Award Numbers: DFG-FZT 118, 202548816; Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS); SLU Centre for Biological Control; Strategic research area Biodiversity and Ecosystem services in a Changing Climate (BECC); US Dept. of Agriculture, National Institute of Food and Agriculture (NIFA), Grant/Award Number: 2020-67021-32477; Volkswagen Foundation through a Freigeist Fellowship, Grant/Award Number: A118199

[Abstract] Here we provide the ‘Global Spectrum of Plant Form and Function Dataset’, containing species mean values for six vascular plant traits. Together, these traits –plant height, stem specific density, leaf area, leaf mass per area, leaf nitrogen content per dry mass, and diaspore (seed or spore) mass – define the primary axes of variation in plant form and function. The dataset is based on ca. 1 million trait records received via the TRY database (representing ca. 2,500 original publications) and additional unpublished data. It provides 92,159 species mean values for the six traits, covering 46,047 species. The data are complemented by higher-level taxonomic classification and six categorical traits (woodiness, growth form, succulence, adaptation to terrestrial or aquatic habitats, nutrition type and leaf type). Data quality management is based on a probabilistic approach combined with comprehensive validation against expert knowledge and external information. Intense data acquisition and thorough quality control produced the largest and, to our knowledge, most accurate compilation of empirically observed vascular plant species mean traits to date. The study has been supported by the TRY initiative on plant traits (https://www.try-db.org). TRY is an initiative of the Max Planck Institute for Biogeochemistry, bioDISCOVERY/Future Earth (ICSU), the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig and Núcleo DiverSus (CONICET- Universidad Nacional de Córdoba, Argentina). The Global Spectrum of Plant Form and Function study has been supported by the European BACI project (Towards a Biosphere Atmosphere change Index, EU grant ID 640176), and grants to SD by FONCyT, CONICET, Universidad Nacional de Córdoba, the Inter-American Institute for Global Change Research, and The Newton Fund (NERC UK – CONICET ARG). VO thanks RSF (#19-14-00038p). Open Access funding enabled and organized by Projekt DEAL

Intraspecific genetic diversity is an important component of biodiversity. A substantial body of evidence has demonstrated positive effects of plant genetic diversity on plant performance. However, it has remained unclear whether plant genetic diversity generally increases plant performance by reducing the pressure of plant antagonists across trophic levels for different plant life forms, ecosystems and climatic zones. Here, we analyse 4702 effect sizes reported in 413 studies that consider effects of plant genetic diversity on trophic groups and their interactions. We found that that increasing plant genetic diversity decreased the performance of plant antagonists including invertebrate herbivores, weeds, plant-feeding nematodes and plant diseases, while increasing the performance of plants and natural enemies of herbivores. Structural equation modelling indicated that plant genetic diversity increased plant performance partly by reducing plant antagonist pressure. These results reveal that plant genetic diversity often influences multiple trophic levels in ways that enhance natural pest control in managed ecosystems and consumer control of plants in natural ecosystems for sustainable plant production.

Ecosystems integrity and services are threatened by anthropogenic global changes. Mitigating and adapting to these changes require knowledge of ecosystem functioning in the expected novel environments, informed in large part through experimentation and modelling. This paper describes 13 advanced controlled environment facilities for experimental ecosystem studies, herein termed ecotrons, open to the international community. Ecotrons enable simulation of a wide range of natural environmental conditions in replicated and independent experimental units while measuring various ecosystem processes. This capacity to realistically control ecosystem environments is used to emulate a variety of climatic scenarios and soil conditions, in natural sunlight or through broad‐spectrum lighting. The use of large ecosystem samples, intact or reconstructed, minimizes border effects and increases biological and physical complexity. Measurements of concentrations of greenhouse trace gases as well as their net exchange between the ecosystem and the atmosphere are performed in most ecotrons, often quasi continuously. The flow of matter is often tracked with the use of stable isotope tracers of carbon and other elements. Equipment is available for measurements of soil water status as well as root and canopy growth. The experiments ran so far emphasize the diversity of the hosted research. Half of them concern global changes, often with a manipulation of more than one driver. About a quarter deal with the impact of biodiversity loss on ecosystem functioning and one quarter with ecosystem or plant physiology. We discuss how the methodology for environmental simulation and process measurements, especially in soil, can be improved and stress the need to establish stronger links with modelling in future projects. These developments will enable further improvements in mechanistic understanding and predictive capacity of ecotron research which will play, in complementarity with field experimentation and monitoring, a crucial role in exploring the ecosystem consequences of environmental changes., Experimentation and modelling are necessary to predict ecosystem functioning under future environments and to develop mitigating and adapting strategies. This paper describes 13 advanced controlled environment facilities, called ecotrons, open to the international community. An ecotron comprises a set of replicated enclosures designed to host ecosystems samples and enable realistic simulations of above‐ and belowground environmental conditions, while simultaneously and automatically measuring ecosystem processes. The characteristics of these infrastructures are given as well as examples of collaborative projects hosted so far.

Intraspecific diversity (genetic diversity) is an important component of biodiversity. A substantial body of evidence has demonstrated positive direct or indirect effects of plant genetic diversity on plant performance. However, it has remained unclear whether plant genetic diversity increases plant performance by reducing the pressure of plant-damaging organisms across trophic levels in different plant life forms, ecosystems and climatic zones. Here, we analyse 4702 effect sizes reported in 413 studies that consider effects of plant genetic diversity on trophic groups and their interactions. We found that increasing plant genetic diversity decreases the performance of plant-damaging organisms including invertebrate herbivores, weeds, plant-feeding nematodes and plant diseases, while increasing the performance of plants and natural enemies of herbivores. We also provide evidence that plant genetic diversity increases plant performance by reducing plant-damaging organism pressure. These results reveal that plant genetic diversity often influences multiple trophic levels in ways that enhance natural pest control in managed ecosystems and consumer control of plants in natural ecosystems for sustainable plant production.

Floral plantings are promoted to foster ecological intensification of agriculture through provisioning of ecosystem services. However, a comprehensive assessment of the effectiveness of different floral plantings, their characteristics and consequences for crop yield is lacking. Here we quantified the impacts of flower strips and hedgerows on pest control (18 studies) and pollination services (17 studies) in adjacent crops in North America, Europe and New Zealand. Flower strips, but not hedgerows, enhanced pest control services in adjacent fields by 16% on average. However, effects on crop pollination and yield were more variable. Our synthesis identifies several important drivers of variability in effectiveness of plantings: pollination services declined exponentially with distance from plantings, and perennial and older flower strips with higher flowering plant diversity enhanced pollination more effectively. These findings provide promising pathways to optimise floral plantings to more effectively contribute to ecosystem service delivery and ecological intensification of agriculture in the future., Our quantitative synthesis of the impacts of floral plantings on pest control, crop pollination and yield reveals that flower strips, but not hedgerows, enhanced pest control services in adjacent fields by 16% on average, while effects on crop pollination and yield were more variable. Our synthesis identifies several important drivers of this variability in effectiveness of plantings: pollination services declined exponentially with distance from plantings, and perennial and older flower strips with higher flowering plant diversity enhanced pollination more effectively, with important implications for the the design and implementation of these measures to effectively promote ecological intensification of agriculture in the future

Summary Urbanization is a pressing challenge for earth’s humans because it is changing not only natural environments but also agricultural lands. Yet, the consequences of cropland loss on pest insect populations that largely depend on these habitats remain largely unclear. We used a 17-year data set to investigate the dynamics of three moth pest species (i.e., striped stem borer, yellow stem borer, and pink stem borer) and their driving forces across the largest mega-urban region of China. Total abundance of three pest species is declined by about 80%, which was strongly associated with cropland loss during rapid urbanization. Our findings indicate that not only the increasing conversion of natural areas to human-dominated landscapes but also that of agricultural lands to urban landscapes can be critical to insect populations. It is therefore essential to monitor and understand the insect dynamics in rapidly urbanizing regions, which are currently found in many developing countries worldwide., Graphical abstract, Highlights • Urbanization has worldwide dramatic impacts on the earth's insects • Its relation to declining farmland pest insect populations remains greatly understudied • Consistent moth population decline coincided with a rapid process of urbanization • About 80% of such decline was due to loss of agricultural land, Ecology; Entomology; Agricultural science; Economic entomology

Aim To date, despite their great potential biogeographical regionalization models have been mostly developed on descriptive and empirical bases. This paper aims at applying the beta‐diversity framework on a statistically representative data set to analytically test the consistency of the biogeographical regionalization of Italian forests. Location Italy. Taxon Vascular plants. Methods Forest plant communities were surveyed in 804 plots made in a statistically representative sample of forest communities made by 201 sites of Italian forests across the three biogeographical regions of the country: Alpine, Continental, and Mediterranean. We conducted an ordination analysis and an analysis of beta‐diversity, decomposing it into its turnover and nestedness components. Results Our results provide only partial support to the consistency of the biogeographical regionalization of Italy. While the differences in forest plant communities support the distinction between the Alpine and the other two regions, differences between Continental and Mediterranean regions had lower statistical support. Pairwise beta‐diversity and its turnover component are higher between‐ than within‐biogeographical regions. This suggests that different regional species pools contribute to assembly of local communities and that spatial distance between‐regions has a stronger effect than that within‐regions. Main conclusions Our findings confirm a biogeographical structure of the species pools that is captured by the biogeographical regionalization. However, nonsignificant differences between the Mediterranean and Continental biogeographical regions suggest that this biogeographical regionalization is not consistent for forest plant communities. Our results demonstrate that an analytical evaluation of species composition differences among regions using beta‐diversity analysis is a promising approach for testing the consistency of biogeographical regionalization models. This approach is recommended to provide support to the biogeographical regionalization used in some environmental conservation polices adopted by EU., This paper aims at applying the beta‐diversity framework on a statistically representative data set to test the consistency of the biogeographical regionalization of Italian forests based on the three different regions recognised within the country. Our results provide only partial support to the consistency of the biogeographical regionalization of Italy based on three regions. Our findings support the existence of a biogeographical structure of the species pools that is captured by the biogeographical regionalization. However, nonsignificant differences between the Mediterranean and Continental biogeographical regions suggest a weakness in this biogeographical regionalization.

2017-2018 Belmont Forum and BiodivERsA joint call for research proposals, under the BiodivScen ERA-Net COFUND programme, and with the funding organisations AEI, NWO, ECCyT and NSF Funding information, Allen-Perkins A, Magrach A, Dainese M, Garibaldi LA, Kleijn D, Rader R, Reilly JR, Winfree R, Lundin O, McGrady CM, Brittain C, Biddinger DJ, Artz DR, Elle E, Hoffman G, Ellis JD, Daniels J, Gibbs J, Campbell JW, Brokaw J, Wilson JK, Mason K, Ward KL, Gundersen KB, Bobiwash K, Gut L, Rowe LM, Boyle NK, Williams NM, Joshi NK, Rothwell N, Gillespie RL, Isaacs R, Fleischer SJ, Peterson SS, Rao S, Pitts-Singer TL, Fijen T, Boreux V, Rundlöf M, Viana BF, Klein AM, Smith HG, Bommarco R, Carvalheiro LG, Ricketts TH, Ghazoul J, Krishnan S, Benjamin FE, Loureiro J, Castro S, Raine NE, de Groot GA, Horgan FG, Hipólito J, Smagghe G, Meeus I, Eeraerts M, Potts SG, Kremen C, García D, Miñarro M, Crowder DW, Pisanty G, Mandelik Y, Vereecken NJ, Leclercq N, Weekers T, Lindstrom SAM, Stanley DA, Zaragoza-Trello C, Nicholson CC, Scheper J, Rad C, Marks EAN, Mota L, Danforth B, Park M, Bezerra ADM, Freitas BM, Mallinger RE, Oliveira da Silva F, Willcox B, Ramos DL, D da Silva E Silva F, Lázaro A, Alomar D, González-Estévez MA, Taki H, Cariveau DP, Garratt MPD, Nabaes Jodar DN, Stewart RIA, Ariza D, Pisman M, Lichtenberg EM, Schüepp C, Herzog F, Entling MH, Dupont YL, Michener CD, Daily GC, Ehrlich PR, Burns KLW, Vilà M, Robson A, Howlett B, Blechschmidt L, Jauker F, Schwarzbach F, Nesper M, Diekötter T, Wolters V, Castro H, Gaspar H, Nault BA, Badenhausser I, Petersen JD, Tscharntke T, Bretagnolle V, Willis Chan DS, Chacoff N, Andersson GKS, Jha S, Colville JF, Veldtman R, Coutinho J, Bianchi FJJA, Sutter L, Albrecht M, Jeanneret P, Zou Y, Averill AL, Saez A, Sciligo AR, Vergara CH, Bloom EH, Oeller E, Badano EI, Loeb GM, Grab H, Ekroos J, Gagic V, Cunningham SA, Åström J, Cavigliasso P, Trillo A, Classen A, Mauchline AL, Montero-Castaño A, Wilby A, Woodcock BA, Sidhu CS, Steffan-Dewenter I, Vogiatzakis IN, Herrera JM, Otieno M, Gikungu MW, Cusser SJ, Nauss T, Nilsson L, Knapp J, Ortega-Marcos JJ, González JA, Osborne JL, Blanche R, Shaw RF, Hevia V, Stout J, Arthur AD, Blochtein B, Szentgyorgyi H, Li J, Mayfield MM, Woyciechowski M, Nunes-Silva P, Halinski de Oliveira R, Henry S, Simmons BI, Dalsgaard B, Hansen K, Sritongchuay T, O'Reilly AD, Chamorro García FJ, Nates Parra G, Magalhães Pigozo C, Bartomeus I

The use of ground cover vegetation is becoming a prominent intervention for promoting biodiversity and associated ecosystem services in Chinese orchards. Despite the large number of studies that have examined the effects of ground cover vegetation on promoting natural enemy populations and related natural pest control, it is less understood whether enhanced natural pest control translates to increase yield and reduced pesticide use. We conducted a 2-year experiment comparing three cover vegetation (ryegrass, clover, and hairy vetch) practices versus a bare ground control in commercial pear orchards in the Yangtze River Delta of East China (YRDEC), China. Natural enemy density (predator and parasitoid abundance), invertebrate herbivore performance (piercing-sucking herbivore abundance and branch-boring and fruit-boring percentage), pesticide input and pear fruit yield were recorded. The results indicated that cover vegetation decreased herbivore abundance and boring percentage by 49.95 and 63.6% respectively, and thus decreased pesticide use by 26.10%. Meanwhile, we found that cover vegetation increased the abundance of natural enemies by 620.75%, and increased pear fruit yield by 6.82%. Piecewise structural equation modelling indicated that increased natural enemy densities, decreased herbivore performance and pesticide use, while increasing fruit yield. Our results confirm that the use of ground cover vegetations (especially with clover and hairy vetch) can promote ecological intensification and biological pest control in pear orchards.

Urbanization is a pressing challenge for earth's human because it is transforming and fragmenting not only natural environments, but also rural lands. Yet, the consequences of rural land-use change on insect populations that depend on these habitats remain largely unclear. We used a 17-year data set to investigate the dynamics of three dominant native farmland moths and its driving forces across the largest megaurban region of China. Total moth abundance declined by about 80%, which was strongly associated with loss and fragmentation of croplands during rapid urbanization. Our findings indicate that urbanization, through loss of traditional agricultural lands, can be a further threat to insect populations. It is therefore really critical to monitor and understand the agrobiodiversity dynamics in rapidly urbanizing regions, which are currently found in many developing countries worldwide.

Several studies have evaluated lichen responses in terms of shifts in species climate suitability, species richness and community composition. In contrast, patterns of co-occurrence among species that could be related to complex species interactions have received less consideration. Biotic interactions play a major role in shaping species niches, fitness and adaptation to new environments. Therefore, considering the specific relationships among co-occurring species is essential to further deepen our knowledge of biodiversity response to climate change. In this perspective, the analysis of lichen ecological networks across elevational gradients may provide a powerful tool to understand how communities are structured and how biotic interactions are modulated by changing climatic conditions. We evaluated the contribution of environmental and species biological attributes to the structure of epiphytic lichen-host tree networks. Specifically, we studied lichen communities considering two different network levels: the whole lichen community, and groups of lichen species that presented similar biological traits. In this framework, we (a) characterized the structure of the epiphytic lichen-host tree networks; (b) assessed how network structure varied with climate, forest attributes and community trait diversity and (c) evaluated the role that biological traits played in the connections established between co-occurring lichens. On the one hand, results indicate that epiphytic lichen communities are dominated by local segregation, suggesting habitat specialization among lichens within their host tree, and that climatic conditions and, to a lesser extent, lichen diversity are the main drivers of community assemblage. On the other hand, the role of lichen species in the networks depends on their particular biological traits, supporting the hypothesis that biological traits contribute to shape network structure by influencing the ability of the species to interact between each other. These findings warn about the potential impact of climate change on epiphytic lichen communities. Synthesis. This study builds towards a better understanding of lichen community assembly and on biodiversity response to climate change in forest alpine ecosystems. In particular, our results highlight the value of lichen-tree networks to inform about assemblage processes acting at different organizational levels and indicate that lichens might become one of the most threatened groups under global change scenarios.

Recent synthesis studies have shown inconsistent responses of crop pests to landscape composition, imposing a fundamental limit to our capacity to design sustainable crop protection strategies to reduce yield losses caused by insect pests. Using a global dataset composed of 5242 observations encompassing 48 agricultural pest species and 26 crop species, we tested the role of pest traits (exotic status, host breadth and habitat breadth) and environmental context (crop type, range in landscape gradient and climate) in modifying the pest response to increasing semi-natural habitats in the surrounding landscape. For natives, increasing semi-natural habitats decreased the abundance of pests that exploit only crop habitats or that are highly polyphagous. On the contrary, populations of exotic pests increased with an increasing cover of semi-natural habitats. These effects might be related to changes in host plants and other resources across the landscapes and/or to modified top-down control by natural enemies. The range of the landscape gradient explored and climate did not affect pests, while crop type modified the response of pests to landscape composition. Although species traits and environmental context helped in explaining some of the variability in pest response to landscape composition, the observed large interspecific differences suggest that a portfolio of strategies must be considered and implemented for the effective control of rapidly changing communities of crop pests in agroecosystems.

Inverters based on power switches, such as IGBTs, in either resonant or hard-switching topologies can, during or after a load-fault, exhibit a transient overvoltage at the collector-emitter leads. In such an event, the maximum allowed collector-emitter voltage may be exceeded and the power switch destroyed. To avoid this, some form of active clamping may be used. In this work, we present a concept of a single possibly co-packed, high-voltage TVS-diode with typical breakdown voltages ranging from 1.2 to 1.7 kV.

Numerous studies have demonstrated that plant species diversity enhances ecosystem functioning in terrestrial ecosystems, including diversity effects on insects (herbivores, predators and parasitoids) and plants. However, the effects of increased plant diversity across trophic levels in different ecosystems and biomes have not yet been explored on a global scale. Through a global meta-analysis of 2,914 observations from 351 studies, we found that increased plant species richness reduced herbivore abundance and damage but increased predator and parasitoid abundance, predation, parasitism and overall plant performance. Moreover, increased predator/parasitoid performance was correlated with reduced herbivore abundance and enhanced plant performance. We conclude that increasing plant species diversity promotes beneficial trophic interactions between insects and plants, ultimately contributing to increased ecosystem services.

Natural control of crop pests has the potential to complement or replace intensive agricultural practices, but its mainstream application requires reliable predictions in diverse socioecological settings. In lack of a widely accepted model of natural pest control, we review existing modelling approaches and critically examine their potential to provide understanding and predictions across agricultural landscapes. Models that explicitly represent the underlying mechanisms are better positioned to represent the diversity and context sensitivity of natural pest control than correlative models. Such mechanistic models have used diverse techniques to represent crop-pest-enemy combinations at various spatiotemporal scales. However, certain regions of the world and socioeconomic aspects of natural pest control are underrepresented, while modelling approaches are restricted by a fundamental trade-off between generality and realism. We propose that modelling natural pest control across agroecosystems requires a framework of context-specific generalizations, based on empirical evidence and theoretical expectations. Reviewed models of natural pest control indicate potential attributes of such a general predictive framework.

Netherlands Organisation for Scientific Research (NWO), Grant/Award Number: 019.171LW.023; German Research Foundation; German Research Foundation DFG, Grant/Award Number: 264740629; FONDECYT, Grant/Award Number: 11150835; CONICYT-PAI, Grant/Award Number: 82130046; 7th European Community Framework Programme, Grant/Award Number: FORECOFUN-SSA PIEF-GA-2010–274798; European Research Council Synergy, Grant/Award Number: ERC-SyG-2013-610028; Austrian Science Foundation, Grant/Award Number: I2086-B16; Czech Science Foundation, Centre of Excellence PLADIAS, Grant/Award Number: 14-15414S and RVO 67985939; EXPRO, Grant/Award Number: 19-28807X; VEGA, Grant/Award Number: 0051/1, van der Sande, M.T., Bruelheide, H., Dawson, W., Dengler, J., Essl, F., Field, R., Haider, S., van Kleunen, M., Kreft, H., Pagel, J., Pergl, J., Purschke, O., Pyšek, P., Weigelt, P., Winter, M., Attorre, F., Aubin, I., Bergmeier, E., Chytrý, M., Dainese, M., De Sanctis, M., Fagundez, J., Golub, V., Guerin, G.R., Gutiérrez, A.G., Jandt, U., Jansen, F., Jiménez-Alfaro, B., Kattge, J., Kearsley, E., Klotz, S., Kramer, K., Moretti, M., Niinemets, Ü., Peet, R.K., Penuelas, J., Petřík, P., Reich, P.B., Sandel, B., Schmidt, M., Sibikova, M., Violle, C., Whitfeld, T.J.S., Wohlgemuth, T., Knight, T.M.

The majority of variation in six traits critical to the growth, survival and reproduction of plant species is thought to be organised along just two dimensions, corresponding to strategies of plant size and resource acquisition. However, it is unknown whether global plant trait relationships extend to climatic extremes, and if these interspecific relationships are confounded by trait variation within species. We test whether trait relationships extend to the cold extremes of life on Earth using the largest database of tundra plant traits yet compiled. We show that tundra plants demonstrate remarkably similar resource economic traits, but not size traits, compared to global distributions, and exhibit the same two dimensions of trait variation. Three quarters of trait variation occurs among species, mirroring global estimates of interspecific trait variation. Plant trait relationships are thus generalizable to the edge of global trait-space, informing prediction of plant community change in a warming world., It is unclear whether plant trait relationships found at the global scale extend to climatic extremes. Here the authors analyse six major aboveground traits to show that known plant trait relationships extend to the tundra biomes and exhibit the same two dimensions of variation detected at the global scale.

Natural control of invertebrate crop pests has the potential to complement or replace conventional insecticide-based practices, but its mainstream application is hampered by predictive unreliability across agroecosystems. Inconsistent responses of natural pest control to changes in landscape characteristics have been attributed to ecological complexity and system-specific conditions. Here, we review agroecological models and their potential to provide predictions of natural pest control across agricultural landscapes. Existing models have used a multitude of techniques to represent specific crop-pest-enemy systems at various spatiotemporal scales, but less wealthy regions of the world are underrepresented. A realistic representation of natural pest control across systems appears to be hindered by a practical trade-off between generality and realism. Nonetheless, observations of context-sensitive, trait-mediated responses of natural pest control to land-use gradients indicate the potential of ecological models that explicitly represent the underlying mechanisms. We conclude that modelling natural pest control across agroecosystems should exploit existing mechanistic techniques towards a framework of contextually bound generalizations. Observed similarities in causal relationships can inform the functional grouping of diverse agroecosystems worldwide and the development of the respective models based on general, but context-sensitive, ecological mechanisms. The combined use of qualitative and quantitative techniques should allow the flexible integration of empirical evidence and ecological theory for robust predictions of natural pest control across a wide range of agroecological contexts and levels of knowledge availability. We highlight challenges and promising directions towards developing such a general modelling framework. (Less)

The abandonment of silvicultural activities can lead to changes in species richness and composition of biological communities, when compared to those found in managed forests. The aim of this study was to compare the multi-taxonomical diversity of two mature silver fir-beech-spruce forests in the southern Dolomites (Italy), corresponding to the European Union habitat type 9130. The two sites share similar ecological and structural characteristics, but differ in their recent management histories. In the last 50 years, one site underwent non-intensive management, while the other was left unmanaged and was included in a forest reserve. The species richness and composition of eight taxa were surveyed in the two sites between 2009 and 2011. The difference in mean species richness between the two forest management types was tested through permutation tests, while differences in species composition were tested by principal coordinates analysis and the permutational multivariate analysis of variance. Mean species richness of soil macrofungi, deadwood lichens, bark beetles, and longhorn beetles were significantly higher in the abandoned than in the non-intensively managed forests. Deadwood fungi and epiphytic lichens did not differ in mean species richness between the two study sites, while mean species richness of ground beetles and birds were higher in the non-intensively managed than in the abandoned forest. Significant differences in species composition between the two sites were found for all the taxa, except for longhorn beetles. These results indicate that improving forest landscape heterogeneity through the creation of a mosaic of abandoned and extensively managed forests should better fulfill the requirements of ecologically different taxa.

Land-use change is one of the primary drivers of species loss, yet little is known about its effect on other components of biodiversity that may be at risk. Here, we ask whether, and to what extent, landscape simplification, measured as the percentage of arable land in the landscape, disrupts the functional and phylogenetic association between primary producers and consumers. Across seven European regions, we inferred the potential associations (functional and phylogenetic) between host plants and butterflies in 561 semi-natural grasslands. Local plant diversity showed a strong bottom-up effect on butterfly diversity in the most complex landscapes, but this effect disappeared in simple landscapes. The functional associations between plant and butterflies are, therefore, the results of processes that act not only locally but are also dependent on the surrounding landscape context. Similarly, landscape simplification reduced the phylogenetic congruence among host plants and butterflies indicating that closely related butterflies become more generalist in the resources used. These processes occurred without any detectable change in species richness of plants or butterflies along the gradient of arable land. The structural properties of ecosystems are experiencing substantial erosion, with potentially pervasive effects on ecosystem functions and future evolutionary trajectories. Loss of interacting species might trigger cascading extinction events and reduce the stability of trophic interactions, as well as influence the longer-term resilience of ecosystem functions. This underscores a growing realization that species richness is a crude and insensitive metric and that both functional and phylogenetic associations, measured across multiple trophic levels, are likely to provide additional and deeper insights into the resilience of ecosystems, and the functions they provide.

We examined the main and interactive effects of factors related to habitat filtering, dispersal dynamics, and biotic interactions, on tree-level population dynamics of a subset of species composing the epiphytic lichen pool in an alpine forest. We tested these processes evaluating the population size of 14 lichen species on six hundred and sixty-five trees within a 2 ha plot located in a high elevation alpine forest of the eastern Italian Alps. Our results indicate that community assembly patterns at the tree-level are underpinned by the simultaneous effects of habitat filtering, dispersal, and biotic interactions on the fine-scale population dynamics. These processes determine how the single species are sorted into community assemblages, contributing to tree-level community diversity and composition patterns. This corroborates the view that the response of lichen communities to environmental gradients, in terms of compositional and diversity shifts, may reflect differential species responses to different drivers.

Mass-flowering crops (MFCs) are increasingly cultivated and might influence pollinator communities in MFC fields and nearby semi-natural habitats (SNHs). Across six European regions and 2 years, we assessed how landscape-scale cover of MFCs affected pollinator densities in 408 MFC fields and adjacent SNHs. In MFC fields, densities of bumblebees, solitary bees, managed honeybees and hoverflies were negatively related to the cover of MFCs in the landscape. In SNHs, densities of bumblebees declined with increasing cover of MFCs but densities of honeybees increased. The densities of all pollinators were generally unrelated to the cover of SNHs in the landscape. Although MFC fields apparently attracted pollinators from SNHs, in landscapes with large areas of MFCs they became diluted. The resulting lower densities might negatively affect yields of pollinator-dependent crops and the reproductive success of wild plants. An expansion of MFCs needs to be accompanied by pollinator-supporting practices in agricultural landscapes., The study was funded by the EU FP7 project “Status and Trends of European Pollinators” (244 090, www.STEP-project.net) and Biodiversa‐FACCE project “Enhancing biodiversity‐based ecosystem services to crops through optimised densities of green infrastructure in agricultural landscapes” (PCIN‐2014‐048, http://www.cec.lu.se/research/ecodeal). JPGV and MV acknowledge support from the Severo Ochoa Program for Centres of Excellence in R+D+I (SEV‐2012‐0262), and FLORMAS (CGL 2012‐33801). JBW, VJW, SGP and SPMR acknowledge the support of Insect Pollinators Initiative research funded jointly by a grant from BBSRC, Defra, NERC, the Scottish Government and the Wellcome Trust, under the Living with Environmental Change Partnership. HGS and RB were supported by the Swedish Research Council FORMAS. JS and DK were supported by the Dutch Ministry of Economic Affairs (BO‐11‐011.01‐011 and KB‐14‐003‐006), AH and ISD were supported by the DFG Collaborative Research Centre 1047 Insect timing, and ISD and MD through the 2013–2014 BiodivERsA/FACCE – JPI project Ecodeal with national funding from BMBF.

Summary Field-margin diversification through conservation and restoration of hedgerows is becoming a prominent intervention for promoting biodiversity and associated ecosystem services in intensive agricultural landscapes. However, how increasing cover of hedgerows in the landscape can affect ecosystem services has rarely been considered. Here, we assessed the effect of increased field-margin complexity at the local scale and increasing cover of hedgerows in the landscape on the provision of pest control, weed control and potential pollination. Locally, three types of field margin were compared as follows: (i) standard grass margin, (ii) simple hedgerow and (iii) complex hedgerow, along two independent gradients of hedgerow cover and arable land cover in the landscape. We performed an exclusion experiment to measure biological control of cereal aphids and assessed natural enemy and pest abundance in the field. We sampled plant weed communities and performed a phytometer experiment to test the effects of pollinators on plant reproductive success. At the local scale, planting a new hedgerow or improving its structural complexity and vegetation diversity did not enhance the delivery of ecosystem services in the neighbouring field. However, high cover of hedgerows in the landscape enhanced aphid parasitism (from 12 to 18%) and potential pollination (visitation rate and seed set increased up to 70%) irrespective of local margin quality. The cover of arable land in the landscape reduced the abundance of plant-dwelling predators and weed diversity, but did not affect the delivery of the investigated ecosystem services. Synthesis and applications. Our results highlight the key importance of the surrounding landscape context, rather than local factors, to the delivery of ecosystem services. This suggests a need for new policies that pay particular attention to the conservation of hedgerows at large scales for promoting multiple ecosystem services in agroecosystems. Specifically, hedgerows can serve to develop a network of ecological corridors that can facilitate the movement of beneficial organisms, such as pollinators and natural enemies in the agricultural matrix. Such interventions may be a ‘low cost–high benefit solution’, since farmers can create or conserve high-quality habitats taking little or no land from crop production and without the need to change their crop management.

The adoption of agro-ecological practices in agricultural systems worldwide can contribute to increased food production without compromising future food security, especially under the current biodiversity loss and climate change scenarios. Despite the increase in publications on agro-ecological research and practices during the last 35 years, a weak link between that knowledge and changed farmer practices has led to few examples of agro-ecological protocols and effective delivery systems to agriculturalists. In an attempt to reduce this gap, we synthesised the main concepts related to biodiversity and its functions by creating a web-based interactive spiral (www.biodiversityfunction.com). This tool explains and describes a pathway for achieving agro-ecological outcomes, starting from the basic principle of biodiversity and its functions to enhanced biodiversity on farms. Within this pathway, 11 key steps are identified and sequentially presented on a web platform through which key players (farmers, farmer networks, policy makers, scientists and other stakeholders) can navigate and learn. Because in many areas of the world the necessary knowledge needed for achieving the adoption of particular agro-ecological techniques is not available, the spiral approach can provide the necessary conceptual steps needed for obtaining and understanding such knowledge by navigating through the interactive pathway. This novel approach aims to improve our understanding of the sequence from the concept of biodiversity to harnessing its power to improve prospects for ‘sustainable intensification’ of agricultural systems worldwide. Refereed/Peer-reviewed

Altres ajuts europeus: P.A.W. was additionally supported by the European Union Fourth Environment and Climate Framework Programme (Project Number ENV4-CT970586)P.A.W. was additionally supported by the European Union Fourth Environment and Climate Framework Programme (Project Number ENV4-CT970586). The tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem functioning. Here we explore the biome-wide relationships between temperature, moisture and seven key plant functional traits both across space and over three decades of warming at 117 tundra locations. Spatial temperature-trait relationships were generally strong but soil moisture had a marked influence on the strength and direction of these relationships, highlighting the potentially important influence of changes in water availability on future trait shifts in tundra plant communities. Community height increased with warming across all sites over the past three decades, but other traits lagged far behind predicted rates of change. Our findings highlight the challenge of using space-for-time substitution to predict the functional consequences of future warming and suggest that functions that are tied closely to plant height will experience the most rapid change. They also reveal the strength with which environmental factors shape biotic communities at the coldest extremes of the planet and will help to improve projections of functional changes in tundra ecosystems with climate warming.

International audience; Plant functional traits directly affect ecosystem functions. At the species level, trait combinations depend on trade-offs representing different ecological strategies, but at the community level trait combinations are expected to be decoupled from these trade-offs because different strategies can facilitate co-existence within communities. A key question is to what extent community-level trait composition is globally filtered and how well it is related to global versus local environmental drivers. Here, we perform a global, plot-level analysis of trait-environment relationships, using a database with more than 1.1 million vegetation plots and 26,632 plant species with trait information. Although we found a strong filtering of 17 functional traits, similar climate and soil conditions support communities differing greatly in mean trait values. The two main community trait axes that capture half of the global trait variation (plant stature and resource acquisitiveness) reflect the trade-offs at the species level but are weakly associated with climate and soil conditions at the global scale. Similarly, within-plot trait variation does not vary systematically with macro-environment. Our results indicate that, at fine spatial grain, macro-environmental drivers are much less important for functional trait composition than has been assumed from floristic analyses restricted to co-occurrence in large grid cells. Instead, trait combinations seem to be predominantly filtered by local-scale factors such as disturbance, fine-scale soil conditions, niche partitioning and biotic interactions.

Summary 1.The decline of managed honeybees and the rapid expansion of mass-flowering crops increase the risk of pollination limitation in crops and raise questions about novel management approaches for wild pollinators in agroecosystems. Adding artificial nesting sites, such as trap nests, can promote cavity-nesting bees in agroecosystems, but effectiveness could be limited by the availability of floral resources in the surrounding landscape and by natural antagonists. 2.In two European regions, we exposed artificial trap nests in paired field boundaries adjacent to oilseed rape (OSR) fields or non-flowering crops for two years within 32 landscapes covering two independent gradients of OSR cover and semi-natural habitat (SNH) cover in the landscape. We analysed the effects of local and landscape-wide floral resource availability, land-use intensity, landscape complexity and natural antagonists on community composition and population dynamics of trap-nesting bees. 3.Number of brood cells showed a strong, three-fold increase in response to the additional nesting sites. Species richness and abundance of cavity-nesting bees that were active during OSR flowering increased significantly with increasing amount of early-season landscape-wide floral resource availability, such as the cultivation of OSR. Later foraging species benefited instead from the availability of late-season alternative flower resources or SNH cover once the mass-flowering had ceased. Density-dependent parasitism increased following mass-flowering, while no density-dependent effect was found during mass-flowering. 4.Structural equation modelling revealed that the influence of floral resource availability on community growth rate was mediated by community size. Community size showed a strong negative effect on community growth rate. Despite positive density-dependent parasitism, antagonists had only weak regulating effects on community growth rate. 5.Synthesis and applications. Trap-nesting bee populations grow markedly with the increasing availability of food resources in the landscape and effectiveness of trap nests is only marginally limited by natural antagonists. Thus, trap nests could be a simple pollinator-supporting strategy to accompany the current expansion of mass-flowering crops, and to ensure pollination services for insect-pollinated crops. Trap nests benefit not only early season active generalist bees during oilseed rape flowering but also species with later phenology if accompanied by other pollinator-supporting practices. This article is protected by copyright. All rights reserved.

A large proportion of European alpine plants are able to spread upslope faster than current climate velocities. Nevertheless, invasive species tend to be particularly effective dispersers, making them an additional pressure on the vulnerable native flora. Climate change is expected to trigger an upward expansion of plants in mountain regions1,2 and, although there is strong evidence that many native species have already shifted their distributions to higher elevations1,3,4,5,6, little is known regarding how fast non-native species might respond to climate change. By analysing 131,394 occurrence records of 1,334 plant species collected over 20 years in the European Alps, we found that non-natives are spreading upwards approximately twice as fast as natives. Whereas the spread of natives was enhanced by traits favouring longer dispersal distances, this was not the case for non-natives. This was due to the non-native species pool already being strongly biased towards species that had traits facilitating spread. A large proportion of native and non-native species seemed to be able to spread upwards faster than the current velocity of climate change. In particular, long-distance dispersal events and proximity to roads proved to be key drivers for the observed rapid spread. Our findings highlight that invasions by non-native species into native alpine communities are a potentially significant additional pressure on these vulnerable ecosystems that are already likely to suffer dramatic vegetation changes with ongoing warming and increasing human activity in mountain regions.

Epiphytic lichens are a functionally important and species-rich component of Alpine forests, including several species of conservation concern. Their dependence on specific host trees predicts that forests with different tree species composition host different lichen communities, enhancing lichen diversity in forest landscapes. In this study, we tested for the first time the effect of forest type on patterns of epiphytic lichen diversity, in the Italian Alps. We sampled the main forest types of the South Tyrol, a typical Alpine region of Italy. We also assessed the influence of factors related to forest structure and climatic conditions. Our results demonstrate that different forest types host statistically different lichen communities, suggesting that the conservation of lichen diversity is entrusted to the maintenance of forest landscape heterogeneity, including forest types of minor economic value and rural habitats. The highest number of species was found in grazed larch forests and in high-elevation spruce forests, while the poorest pool was found in low-elevation spruce forests, beech forests and Scots pine (Pinus sylvestris) forests. High-elevation spruce forests also had the highest number of red-listed lichens, as the non-intensive management of these forest type allows the establishment of a rich lichen biota. Our results also emphasize the role for lichen conservation of some forest types that are of minor economic importance, such as oak (Quercus pubescens), riparian, and silver-fir (Abies alba) forests. This can also apply to grazed larch (Larix decidua) forests that are maintained by traditional farming, which shape one of the most pleasing aspects of the Italian Alpine landscapes. © 2014 Elsevier Ltd and The British Mycological Society.

Background and aims Hedges, semi-natural landscape components, have the ability to integrate both agronomic and environmental functions and to provide several ecosystem services. The aim of this study was to test whether hedgerow vegetation is a determinant of soil organic matter properties in ancient agricultural lands.

Capercaillie (Tetrao urogallus L.), a territorial galliform species, is known to prefer mature conifer stands with canopy gaps and a vigorous understory of ericaceous species. Capercaillie is a useful umbrella species that has recently shown declining population trends and distribution changes in its southern geographic range. We aim to identify and assess the possible changes in summer capercaillie habitat selection between 2001 and 2011 in the Scanuppia Natura 2000 site (south-eastern Alps). The area is dominated by spruce (Picea abies (L.) Karsten) forests, followed by mixed forests, scrub, and open habitats. In both years, summer presence&ndash, absence of capercaillie was verified through the detection of droppings over 10 m radius circular plots located along contour lines (1500&ndash, 1800 m). A set of environmental and habitat features was also surveyed. While overall population numbers remain unchanged over the surveyed period, results have shown an altitudinal shift in capercaillie distribution. Habitat variables had a stronger effect on the presence of capercaillie in 2001 than in 2011. Land cover and climate change are likely among the drivers of the shift in altitudinal distribution. This confirms the relevance of habitat restoration actions and to monitor changes in factors explaining capercaillie habitat selection.

In the Alps, many forests are under abandonment because of direct protection or the unprofitability of timber production. The objective of this study was to analyse the effect of silviculture abandonment on the species richness and composition of epiphytic and dead wood-dwelling lichens in silver fir woodlands. An abandoned and a currently non-intensively managed forest watershed of the eastern Italian Alps that were matched for topography, stand structure, plant community and history of use were selected and randomly sampled for the lichen diversity of their silver fir mature stands. Generalised linear mixed models were used for the analyses of the species richness, whereas the species composition patterns were explored by redundancy analysis. The diversity of both of the lichen guilds were explained by the microhabitat conditions related to the contrasting management regimes, but they had opposite responses to the abandonment of the silvicultural activities. The epiphytic lichen communities were richer in species in the managed than in the abandoned silver fir woodlands. However, the effect of a 50 year management cessation on the epiphytic lichens may change in the long term when natural disturbances create gaps and increase the attributes of old-growth forests. The dead wood-dwelling lichen species richness was higher in the abandoned forest because an increased availability of types of dead wood is usually rare in managed forests. The dead wood-dwelling lichen communities of the managed forests were a subset of a more diverse community that was developing in the abandoned forest. Our results indicated that, in non-intensively managed silver fir mature stands, lichen diversity may benefit from the retention of logs and snags, which provide habitat features typical of old-growth forests.

Black locust ( Robinia pseudoacacia L.) is a widespread alien tree species commonly thought to influence plant assemblages. The aim of this study was to compare the plant diversity between black locust and native recent secondary stands within the European Mediterranean Mountains environmental zone. Spontaneous reforestation was detected by comparing historical aerial photographs and the most recent images. Distributed throughout a 2700 km 2 hilly and piedmont area, 32 black locust and 32 paired native stands were selected and all vascular plant species were surveyed in a 100 m 2 area. Analyses of the α and β -diversity were performed separately for six identified plant groups. Despite a clear difference in the tree diversity between the black locust and native recent secondary stands and a homogenisation of the tree layer by the black locust stands, we found only inconsistent hints for homogenisation of the ground-layer vegetation by the black locust stands. There is no evidence to suggest that the presence of black locust in recent secondary stands plays a major role in shaping the diversity of the understory plant groups compared to native stands.

An understanding of the climate conditions governing spatial variation in the reproductive performance of plants can provide important information about the factors characterizing plant community structure, especially in the context of climate change. This study focuses on the effect of climate on the sexual reproductive output of Dactylis glomerata L., a perennial grass species widely distributed throughout temperate regions. An indirect space-for-time substitution procedure was used. Sixty mountain populations of the same target species were surveyed along an elevation gradient, and then, a relevant climate model was used to infer a potential response to climate change over time. Within each population, information on the number of stems, seed number and seed mass were collected. Resource investment in reproduction (RIR) was quantified as seed number × seed mass. A clear variation was found in the reproductive performance of D. glomerata along the elevational gradient: RIR improved with increasing temperature. The best model included only one term: the maximum temperature of the warmest month. This study demonstrates that mountain ecosystems offer particularly good opportunities to study climate effects over relatively short distances and suggests that warming will enhance D. glomerata’s reproductive output throughout its elevational range. Furthermore, it can be hypothesized that a potential migration of D. glomerata toward higher altitudes may occur in response to accelerated climate change.

The main aim of this study was to elucidate the roles of terrain age and spatial self-organisation as drivers of primary succession using high-resolution assessment of plant composition, functional traits and landscape metrics. We sampled 46 plots, 1m x 1m each, distributed along a 15-70 year range of terrain ages on the foreland of the Nardis glacier, located in the southern central Alps of Italy. From existing databases, we selected nine quantitative traits for the 16 plant species present, and we measured a set of seven landscape metrics, which described the spatial arrangement of the plant species patches on the study plots, at a 1cm x 1cm resolution. We applied linear models to study the relationships among plant communities, landscape metrics and terrain age. Furthermore, we used RLQ-analysis to examine trait-spatial configuration relations. To assess the effect of terrain age variation on trait performance, we applied a partial-RLQ analysis approach. Finally, we used the fourth-corner statistic to quantify and test relations between traits, landscape metrics and RLQ axes. Surprisingly, linear models revealed that neither the plant composition nor any of the landscape metrics differed among the three classes of terrain age distinguished, viz. 15-41 y, 41-57 y and 57-66 y, respectively. Further, no correlations were detected between trait patterns and terrain age, however, the floristically defined relevé clusters differed significantly with regard to several landscape metrics and suggestive relationships between increasing patch diversity and traits connected to growth rate were detected. We conclude that (i) terrain age below 70 years is not a good predictor for neither plant composition nor spatial configuration on the studied microhabitat and (ii) the small-scale configuration of the plant species patches correlates with certain functional traits and with plant composition, suggesting species-based spatial self-organisation.

Spatial patterns of vegetation arise from an interplay of functional traits, environmental characteristics and chance. The retreat of glaciers offers exposed substrates which are colonised by plants forming distinct patchy patterns. The aim of this study was to unravel whether patch-level landscape metrics of plants can be treated as functional traits. We sampled 46 plots, each 1 m × 1 m, distributed along a restricted range of terrain age and topsoil texture on the foreland of the Nardis glacier, located in the South-Eastern Alps, Italy. Nine quantitative functional traits were selected for 16 of the plant species present, and seven landscape metrics were measured to describe the spatial arrangement of the plant species’ patches on the study plots, at a resolution of 1 cm × 1 cm. We studied the relationships among plant communities, landscape metrics, terrain age and topsoil texture. RLQ-analysis was used to examine trait-spatial configuration relationships. To assess the effect of terrain age and topsoil texture variation on trait performance, we applied a partial-RLQ analysis approach. Finally, we used the fourth-corner statistic to quantify and test relationships between traits, landscape metrics and RLQ axes. Floristically-defined relevé clusters differed significantly with regard to several landscape metrics. Diversity in patch types and size increased and patch size decreased with increasing canopy height, leaf size and weight. Moreover, more compact patch shapes were correlated with an increased capacity for the conservation of nutrients in leaves. Neither plant species composition nor any of the landscape metrics were found to differ amongst the three classes of terrain age or topsoil texture. We conclude that patch-level landscape metrics of plants can be treated as species-specific functional traits. We recommend that existing databases of functional traits should incorporate these type of data.

The desaturation and charge recovery behavior for 1200-V RC-IGBTs with diode control is investigated. The low thickness of the drift-region of modern 1200-V IGBTs results in significantly reduced time constants of the diode-control feature. While a low desaturation time constant is well acceptable, the recovery time constant becomes critical when compared to typical locking time requirements of common gate driver units. The impact of different locking times on the overall performance is discussed and a novel device concept for RC-IGBTs is presented which overcomes this issue. The FWD-mode of the novel RC-IGBT is desaturated at a gate-emitter voltage of 0 V allowing for the first time a desaturation pulse pattern which may disregard the locking time requirements of the driving-unit.

In mountain areas of touristic interest the evaluation of the impact of human activities is crucial for ensuring long-term conservation of ecosystem biodiversity, functions and services. This study aimed at verifying the biological impact of polycyclic aromatic hydrocarbon (PAH) emissions due to traffic along the roads leading to seven passes of the Dolomites (SE Alps), which were recently declared a UNESCO World Heritage Site. Thalli of the epiphytic lichen Pseudevernia furfuracea, collected at increasing distances from the roads, were used as biomonitors. Our study revealed a gradient of decreasing PAH pollution within 300. m from the roads. Differences among passes were evident mainly for samples collected nearest to the roads, but PAH concentrations at 300. m were almost always higher than those of undisturbed reference sites, indicating that traffic PAH pollution may impact natural ecosystems and lichen diversity at relatively long distances from the emission source.

The introduction and conservation of field margins have been proposed as an intervention to counteract the decline in farmland biodiversity. However, how these margins can affect the movement of species and individuals (i.e. spillover) of natural enemies between field margins and crop is still unclear. In this work, we investigated the spillover of two different groups of natural enemies: tachinids (Diptera: Tachinidae) and aphidophagous hoverflies (Diptera: Syrphidae). For comparison we also investigated the response of non-aphidophagous hoverflies. We examined the spillover from two types of field margin (grass margin vs. hedgerow + grass margin) to adjacent maize fields located in landscapes with different proportion of arable land. The spillover of natural enemies was affected by the field margins, but the response varied between insect groups. The spillover of tachinids was higher from the grass margin than from hedgerows, suggesting that the spillover of this group may be related to the low contrast between the vegetation structure of the margin and the crop. In contrast to tachinids, the abundance of aphidophagous hoverflies was higher toward the center of the crop field, independently of the type of field margin. The spillover of non-aphidophagous hoverflies was not affected by the type of field margin. These species were only affected by the landscape composition as their species richness and abundance were higher in landscapes with low amounts of arable land. Measures focusing on the creation and management of field margins need to consider the local contrast between field margins and crops in relation to the life-history traits of different taxa.

While it is well known that the success of alien plants in new environments greatly depends on their functional traits, to date only a few other studies have tested whether coexisting alien and native species show converging or diverging functional attributes. To our knowledge, no comparative analysis between native and alien species has been carried out in the same mountain habitats. We characterized the main habitats of the Italian Alps on the basis of plant species traits and we then tested for evidence of functional axes of variation among the habitats for native and alien plants. Finally, we tested the 'try-harder' and the 'join-the-locals' hypotheses to understand whether coexisting native and alien plant species showed converging or diverging functional attributes. Ordination analysis showed a distribution of the habitats according to the Grime's CSR strategies, and associated to plant growth form and resource acquisition. Co-inertia analysis showed a significant association between native and alien plant traits at habitat level (RV = 0.73; Monte-Carlo test, p = 0.035). Across all species and habitats, the comparative analysis of individual traits showed that alien species have 25% higher plant height, 250% higher leaf mass, 19% lower leaf dry matter content, 10% higher SLA, and 17% longer flowering duration than native species. Overall, our findings demonstrated that aliens differ in many traits from native species in the Italian Alps, but that many of these differences disappear when one compares aliens and natives that co-occur in the same types of habitats.

Modeling the environmental benefits of urban trees requires data which relate crown height, crown diameter, and leaf area to tree age or stem diameter (DBH). Growth prediction curves, that can be derived from the same data, can also be very useful for a better planning, design and development of the urban forest. However, very little information is available on the growth behavior of urban trees, and limited to few species and regional contexts. The aim of this study was to determine the relationships between tree age and various parameters of tree size in order to develop models to predict the growth of the most important species of an urban forest in northeastern Italy. The logarithmic regression model, proposed by Peper et al., 2001a , Peper et al., 2001b and applied by Stoffberg et al., 2008 , Stoffberg et al., 2009 , and other equations were tested in order to obtain the best fit for each species and parameter. All the models provided a better fit for the larger species (Tilia x vulgaris Hayne, Fraxinus angustifolia Vahl., Acer platanoides L.) than for the smaller ones (Prunus cerasifera “pissardi” (Carriere) L.H. Bailey and Lagerstroemia indica L.). The equations for predicting tree sizes and leaf area are presented and applied to compare size and growth 15 and 25 years after planting. According to the models A. platanoides attained the largest average annual DBH growth with values ranging from an average of 1.25 cm years−1 between 0 and 15 years after planting and 1.52 cm years−1 between 15 and 25 years after planting. L. indica showed the smaller DBH growth, ranging from 0.34 cm years−1 in the first period to 0.48 cm years−1 in the second period. 25 years after planting. A. platanoides L. is the tallest species and reaches the largest crown diameter, whith the largest average annual growth, followed by F. angustifolia and Tilia x vulgaris that show similar growth patterns. A comparison with predicted sizes in other studies confirms the need to extend the knowledge to the behavior of more species and more site specific conditions.

Due to agricultural intensification, semi-natural Arrhenatherion elatioris meadows are becoming rare in central Europe. Despite the increasing importance of their biodiversity value, little information is available on seed production which could be used to enlarge their regional presence. To contribute to this knowledge, the seed production of the major grass species were analysed for the spring growths of an Arrhenatherion elatioris meadow in 2003 and 2004. In the first study year, fertile culms of Anthoxanthum odoratum, Arrhenatherum elatius, Avenula pubescens, Dactylis glomerata, Holcus lanatus and Trisetum flavescens were collected on different dates and analysed for their reproductive efficiency. Floret site utilization was greater than 0AE60 for all species and seed viability was above 80%, except for A. odoratum. Seed dormancy was present to a small extent only in A. odoratum and A. pubescens. With regard to the whole meadow, the density of fertile stems amounted to 850 m )2 (811 m )2 of which were grasses) and standing seed yield at seed maturity of the six grasses was about 33 100 seeds m )2 . As a consequence of the increase in viability occurring during seed development, the maximum standing viable seed yield was reached later. The total number of seeds produced throughout the spring growth period was 2AE8 times that of the maximum standing seed yield. The quality and quantity of the seed production from spring growth make it suitable for establishing species-rich seminatural grassland provided that seed obtained from the second cut is included to increase the presence of legumes and forbs.

The effectiveness of conservation interventions for maximizing biodiversity benefits from agri-environment schemes (AESs) is expected to depend on the quantity of seminatural habitats in the surrounding landscape. To verify this hypothesis, we developed a hierarchical sampling design to assess the effects of field boundary type and cover of seminatural habitats in the landscape at two nested spatial scales. We sampled three types of field boundaries with increasing structural complexity (grass margin, simple hedgerow, complex hedgerow) in paired landscapes with the presence or absence of seminatural habitats (radius 0.5 km), that in turn, were nested within 15 areas with different proportions of seminatural habitats at a larger spatial scale (10 X 10 km). Overall, 90 field boundaries were sampled across a Mediterranean'region (northeastern Italy). We considered species richness response across three different taxonomic groups: vascular plants, butterflies, and tachinid flies. No interactions between type of field boundary and surrounding landscape were found at either 0.5 and 10 km, indicating that the quality of field boundary had the same effect irrespective of the cover of seminatural habitats. At the local scale, extended-width grass margins yielded higher plant species richness, while hedgerows yielded higher species richness of butterflies and tachinids. At the 0.5-km landscape scale, the effect of the proportion of seminatural habitats was neutral for plants and tachinids, while butterflies were positively related to the proportion of forest. At the 10-km landscape scale, only butterflies responded positively to the proportion of seminatural habitats. Our study confirmed the importance of testing multiple scales when considering species from different taxa and with different mobility. We showed that the quality of field boundaries at the local scale was an important factor in enhancing farmland biodiversity. For butterflies, AESs should focus particular attention on preservation'of forest patches in agricultural landscapes within 0.5 kin, as well as the conservation of seminatural habitats at a wider landscape scale.