An increasing number of studies have reported on forest declines and vegetation shifts triggered by drought. In the Swiss Rhone valley (Valais), one of the driest inner‐Alpine regions, the species ...composition in low elevation forests is changing: The sub‐boreal Scots pine (Pinus sylvestris L.) dominating the dry forests is showing high mortality rates. Concurrently the sub‐Mediterranean pubescent oak (Quercus pubescens Willd.) has locally increased in abundance. However, it remains unclear whether this local change in species composition is part of a larger‐scale vegetation shift. To study variability in mortality and regeneration in these dry forests we analysed data from the Swiss national forest inventory (NFI) on a regular grid between 1983 and 2003, and combined it with annual mortality data from a monitoring site. Pine mortality was found to be highest at low elevation (below 1000 m a.s.l.). Annual variation in pine mortality was correlated with a drought index computed for the summer months prior to observed tree death. A generalized linear mixed‐effects model indicated for the NFI data increased pine mortality on dryer sites with high stand competition, particularly for small‐diameter trees. Pine regeneration was low in comparison to its occurrence in the overstorey, whereas oak regeneration was comparably abundant. Although both species regenerated well at dry sites, pine regeneration was favoured at cooler sites at higher altitude and oak regeneration was more frequent at warmer sites, indicating a higher adaptation potential of oaks under future warming. Our results thus suggest that an extended shift in species composition is actually occurring in the pine forests in the Valais. The main driving factors are found to be climatic variability, particularly drought, and variability in stand structure and topography. Thus, pine forests at low elevations are developing into oak forests with unknown consequences for these ecosystems and their goods and services.
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Aims. The aim of our study is to investigate the physical properties of the star-forming interstellar medium (ISM) in the Large Magellanic Cloud (LMC) by separating the origin of the emission lines ...spatially and spectrally. The LMC provides a unique local template to bridge studies in the Galaxy and high redshift galaxies because of its low metallicity and proximity, enabling us to study the detailed physics of the ISM in spatially resolved individual star-forming regions. Following Okada et al. (Okada, Y., Requena-Torres, M. A., Güsten, R., et al. 2015, A&A, 580, A54), we investigate different phases of the ISM traced by carbon-bearing species in four star-forming regions in the LMC, and model the physical properties using the KOSMA-τ PDR model. Methods. We mapped 3–13 arcmin2 areas in 30 Dor, N158, N160, and N159 along the molecular ridge of the LMC in C II 158 μm with GREAT on board SOFIA. We also observed the same area with CO(2-1) to (6-5), 13CO(2-1) and (3-2), C I 3P1–3P0 and 3P2–3P1 with APEX. For selected positions in N159 and 30 Dor, we observed O I 145 μm and O I 63 μm with upGREAT. All spectra are velocity resolved. Results. In all four star-forming regions, the line profiles of CO, 13CO, and C I emission are similar, being reproduced by a combination of Gaussian profiles defined by CO(3-2), whereas C II typically shows wider line profiles or an additional velocity component. At several positions in N159 and 30 Dor, we observed the velocity-resolved O I 145 and 63 μm lines for the first time. At some positions, the O I line profiles match those of CO, at other positions they are more similar to the C II profiles. We interpret the different line profiles of CO, C II and O I as contributions from spatially separated clouds and/or clouds in different physical phases, which give different line ratios depending on their physical properties. We modeled the emission from the CO, C I, C II, and O I lines and the far-infrared continuum emission using the latest KOSMA-τ PDR model, which treats the dust-related physics consistently and computes the dust continuum SED together with the line emission of the chemical species. We find that the line and continuum emissions are not well-reproduced by a single clump ensemble. Toward the CO peak at N159 W, we propose a scenario that the CO, C II, and O I 63 μm emission are weaker than expected because of mutual shielding among clumps.
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Aims
Resurveys of vegetation plots are prone to several errors that can result in misleading conclusions. Minimizing such errors and finding alternative approaches for analyzing resurvey data are ...therefore important. We focused on inter‐observer error and excluded other sources of variation. Our main questions were: How large is the inter‐observer error (i.e. pseudoturnover) in vegetation surveys, and can it be reduced by simple data aggregation approaches? Which factors are affecting pseudoturnover and does it vary between morphological species groups or change over time? Is ecological inference robust against inter‐observer differences?
Location
Switzerland.
Methods
Over seven years, we double‐surveyed a total of 224 plots that were marked once in the field and then sampled by two observers independently on the same day. Both observers conducted full vegetation surveys, recording all vascular plant species, their cover, and additional plot information. We then calculated mean ecological indicator values and pseudoturnover.
Results
Average pseudoturnover was 29% when raw species lists were compared. However, by applying simple aggregation steps to the species list, pseudoturnover was reduced to 17%. Pseudoturnover further varied among habitat types and declined over the years, indicating a training effect among observers. Most overlooked taxa, responsible for pseudoturnover, had low cover values. Mean ecological indicator values were robust against inter‐observer differences.
Conclusions
To minimize pseudoturnover, we suggest continuous training of observers and species‐list aggregation prior to analysis. As mean ecological indicator values were robust against inter‐observer differences, we conclude that they can provide a reliable estimate of temporal vegetation and ecological changes.
Over seven years, 224 vegetation plots were double‐surveyed by two observers independently on the same day to test for inter‐observer differences (pseudoturnover). By applying simple aggregation steps to the species list, average pseudoturnover was reduced from 29% (raw species lists compared) to 17%. Overlooking taxa with low cover values was responsible for pseudoturnover, and mean ecological indicator values were robust against inter‐observer differences, indicating that they are a reliable estimate of temporal vegetation changes.
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Aims: Phytosociological classification of fen vegetation (Scheuchzerio palustris-Caricetea fuscae class) differs among European countries. Here we propose a unified vegetation classification of ...European fens at the alliance level, provide unequivocal assignment rules for individual vegetation plots, identify diagnostic species of fen alliances, and map their distribution. Location: Europe, western Siberia and SE Greenland. Methods: 29 049 vegetation-plot records of fens were selected from databases using a list of specialist fen species. Formal definitions of alliances were created using the presence, absence and abundance of Cocktail-based species groups and indicator species. DCA visualized the similarities among the alliances in an ordination space. The ISOPAM classification algorithm was applied to regional subsets with homogeneous plot size to check whether the classification based on formal definitions matches the results of unsupervised classifications. Results: The following alliances were defined: Caricion viridulo-trinervis (sub-halo-phytic Atlantic dune-slack fens), Caricion davallianae (temperate calcareous fens), Caricion atrofusco-saxatilis (arcto-alpine calcareous fens), Stygio-Caricion limosae (boreal topogenic brown-moss fens), Sphagno warnstorfii-Tomentypnion nitentis (Sphagnum-brown-moss rich fens), Saxifrago-Tomentypnion (continental to boreo-continental nitrogen-limited brown-moss rich fens), Narthecion scardici (alpine fens with Balkan endemics), Caricion stantis (arctic brown-moss rich fens), Anagallido tenellae-Juncion bulbosi (Ibero-Atlantic moderately rich fens), Drepanocladion exannulati (arcto-boreal-alpine non-calcareous fens), Caricion fuscae (temperate moderately rich fens), Sphagno-Caricion canescentis (poor fens) and Scheuchzerion palustris (dystrophic hollows). The main variation in the species composition of European fens reflected site chemistry (pH, mineral richness) and sorted the plots from calcareous and extremely rich fens, through rich and moderately rich fens, to poor fens and dystrophic hollows. ISOPAM classified regional subsets according to this gradient, supporting the ecological meaningfulness of this classification concept on both the regional and continental scale. Geographic/macroclimatic variation was reflected in the second most important gradient. Conclusions: The pan-European classification of fen vegetation was proposed and supported by the data for the first time. Formal definitions developed here allow consistent and unequivocal assignment of individual vegetation plots to fen alliances at the continental scale.
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A typical degraded mountain bog in the Swiss Alps was restored by cessation of grazing and partial rewetting. We observed the development of the vegetation over 15 years, starting immediately after ...the grazing cessation (4 years before rewetting). Cessation of grazing stimulated the recolonisation of bare peat and the establishment of bryophytes. While many typical bog forest species benefited from grazing cessation, the relative abundance of Cyperaceae decreased. Rewetting (in our case: closing ditches with sheet piles and filling them with sawdust) as an additional restoration measure, had a stabilising effect on most environmental factors (e.g. water availability, soil aeration). Furthermore, rewetting had a stabilising effect on stress tolerators and promoted typical species of bog hummocks and hollows. The abundances of species of nearly all groups changed far less dynamically in the rewetted area than in the area that remained drained. It turned out that cessation of grazing as the only restoration measure was insufficient to maintain the vegetation of bogs, whereas the combination of grazing cessation and rewetting directed the site towards the desired development. However, even eleven years after rewetting and 15 years after cessation of grazing, the site had not yet reached a state that was close to an undisturbed alpine bog.
Written by an expert in the field, this book covers the principles, architectures, applications, specifications and characterizations of radio receivers In this book, the author introduces the reader ...to the basic principles and theories of present-day communications receiver technology. The first section of the book presents realization concepts at the system level, taking into consideration the various types of users. Details of the circuitry are described providing the reader with an understanding of fully digitized radio receivers, offering an insight into the state-of-the-art. The remaining sections address radio receivers, particularly as two-port devices. Furthermore, the author outlines the fields of applications and their features (with sample calculations and with reference to practical work), and considers the speciality of high-quality radio receivers. As can be seen from the multitude of terrestrial applications described in Part II, they are typically used for radio surveillance, signal intelligence, modern radio bearing and classical radio services. Parts III and IV describe the entire range of parameters that are useful for the characterization of these receivers. The description starts from the physical effect, or the explanation of the individual parameter, and then proceeds to the measuring technique for determining the parameters, highlighting problems, followed by explanatory notes with applicatory relevance. The measuring procedures described are the result of experiences gained in extended laboratory work and practical testing. With the model shown in Part IV used for the operational evaluation detailing the intrinsic small range of interpretation, the book covers untreated research in the field. The Appendix provides valuable information about the dimensions of receiving systems and the mathematical derivation of effects. The book also includes a useful method for converting different level specifications. Key Features:
• Introduces the basic principles and theories of present-day technology
• Discusses concepts at the system level (aligned to the various types of users)
• Addresses fully digitized radio receivers focusing on the state-of-the-art
• Close contacts to the industry were utilized to show background information
• Enables the reader to comprehend and evaluate the characteristic features and the performance of such systems
• Examines the entire range of parameters that are characteristic of the technology including the physical effect and measuring techniques
• Includes results of experiences gained in extended laboratory work and practical testing with examples
• Provides a uniform and systematic approach for ease of understanding e.g. many didactic figures for the
visual illustration have been newly created as well as complete real-world examples This book will be an excellent resource for professionals developing and testing radio receivers, for receiver users (e.g. at regulatory agencies, surveillance centres, secret services, classical radio communications services), engineers and technicians who work with RF-measurement instruments, postgraduate students studying the field and university lecturers. Chartered radio amateurs and handlers/operators will also find this book insightful. Due to high level of detail, it also serves as a reference. By using the carefully edited alphabetical index with over 1,200 entries, the appropriate explanations can be found quickly in the text.
Aim
The EUNIS Habitat Classification is a widely used reference framework for European habitat types (habitats), but it lacks formal definitions of individual habitats that would enable their ...unequivocal identification. Our goal was to develop a tool for assigning vegetation‐plot records to the habitats of the EUNIS system, use it to classify a European vegetation‐plot database, and compile statistically‐derived characteristic species combinations and distribution maps for these habitats.
Location
Europe.
Methods
We developed the classification expert system EUNIS‐ESy, which contains definitions of individual EUNIS habitats based on their species composition and geographic location. Each habitat was formally defined as a formula in a computer language combining algebraic and set‐theoretic concepts with formal logical operators. We applied this expert system to classify 1,261,373 vegetation plots from the European Vegetation Archive (EVA) and other databases. Then we determined diagnostic, constant and dominant species for each habitat by calculating species‐to‐habitat fidelity and constancy (occurrence frequency) in the classified data set. Finally, we mapped the plot locations for each habitat.
Results
Formal definitions were developed for 199 habitats at Level 3 of the EUNIS hierarchy, including 25 coastal, 18 wetland, 55 grassland, 43 shrubland, 46 forest and 12 man‐made habitats. The expert system classified 1,125,121 vegetation plots to these habitat groups and 73,188 to other habitats, while 63,064 plots remained unclassified or were classified to more than one habitat. Data on each habitat were summarized in factsheets containing habitat description, distribution map, corresponding syntaxa and characteristic species combination.
Conclusions
EUNIS habitats were characterized for the first time in terms of their species composition and distribution, based on a classification of a European database of vegetation plots using the newly developed electronic expert system EUNIS‐ESy. The data provided and the expert system have considerable potential for future use in European nature conservation planning, monitoring and assessment.
EUNIS Habitat Classification is a standard classification of European habitats. We developed the classification expert system EUNIS‐ESy, which assigns vegetation plots to EUNIS habitats based on their species composition and geographic location. We classified 1,261,373 vegetation plots from the European Vegetation Archive and determined characteristic species combinations and prepared distribution maps for 199 habitats at Level 3 of EUNIS hierarchy.
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It is generally assumed that restoring biodiversity will enhance diversity and ecosystem functioning. However, to date, it has rarely been evaluated whether and how restoration efforts manage to ...rebuild biodiversity and multiple ecosystem functions (ecosystem multifunctionality) simultaneously. Here, we quantified how three restoration methods of increasing intervention intensity (harvest only < topsoil removal < topsoil removal + propagule addition) affected grassland ecosystem multifunctionality 22 yr after the restoration event. We compared restored with intensively managed and targeted seminatural grasslands based on 13 biotic and abiotic, above- and belowground properties. We found that all three restoration methods improved ecosystem multifunctionality compared to intensively managed grasslands and developed toward the targeted seminatural grasslands. However, whereas higher levels of intervention intensity reached ecosystem multifunctionality of targeted seminatural grasslands after 22 yr, lower intervention missed this target. Moreover, we found that topsoil removal with and without seed addition accelerated the recovery of biotic and aboveground properties, and we found no negative long-term effects on abiotic or belowground properties despite removing the top layer of the soil. We also evaluated which ecosystem properties were the best indicators for restoration success in terms of accuracy and cost efficiency. Overall, we demonstrated that low-cost measures explained relatively more variation of ecosystem multifunctionality compared to high-cost measures. Plant species richness was the most accurate individual property in describing ecosystem multifunctionality, as it accounted for 54% of ecosystem multifunctionality at only 4% of the costs of our comprehensive multifunctionality approach. Plant species richness is the property that typically is used in restoration monitoring by conservation agencies. Vegetation structure, soil carbon storage and water-holding capacity together explained 70% of ecosystem multifunctionality at only twice the costs (8%) of plant species richness, which is, in our opinion, worth considering in future restoration monitoring projects. Hence, our findings provide a guideline for land managers how they could obtain an accurate estimate of aboveground-belowground ecosystem multifunctionality and restoration success in a highly cost-efficient way.
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Aims
Ellenberg‐type indicator values are expert‐based rankings of plant species according to their ecological optima on main environmental gradients. Here we extend the indicator‐value system ...proposed by Heinz Ellenberg and co‐authors for Central Europe by incorporating other systems of Ellenberg‐type indicator values (i.e., those using scales compatible with Ellenberg values) developed for other European regions. Our aim is to create a harmonized data set of Ellenberg‐type indicator values applicable at the European scale.
Methods
We collected European data sets of indicator values for vascular plants and selected 13 data sets that used the nine‐, ten‐ or twelve‐degree scales defined by Ellenberg for light, temperature, moisture, reaction, nutrients and salinity. We compared these values with the original Ellenberg values and used those that showed consistent trends in regression slope and coefficient of determination. We calculated the average value for each combination of species and indicator values from these data sets. Based on species’ co‐occurrences in European vegetation plots, we also calculated new values for species that were not assigned an indicator value.
Results
We provide a new data set of Ellenberg‐type indicator values for 8908 European vascular plant species (8168 for light, 7400 for temperature, 8030 for moisture, 7282 for reaction, 7193 for nutrients, and 7507 for salinity), of which 398 species have been newly assigned to at least one indicator value.
Conclusions
The newly introduced indicator values are compatible with the original Ellenberg values. They can be used for large‐scale studies of the European flora and vegetation or for gap‐filling in regional data sets. The European indicator values and the original and taxonomically harmonized regional data sets of Ellenberg‐type indicator values are available in the Supporting Information and the Zenodo repository.
This paper introduces a harmonized data set of Ellenberg‐type indicator values applicable at the European scale. We collected 13 regional data sets of indicator values for vascular plants compatible with Ellenberg scales and calculated a new data set of Ellenberg‐type indicator values for 8,908 European vascular plant species.
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![Velocity profiles of [CII],...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0004-6361/small "Velocity profiles of [CII], [CI], CO, and [OI] and physical conditions in four star-forming regions in the Large Magellanic Cloud")
