Directional turnover towards larger-ranged plants over time and across habitats

Species turnover is ubiquitous. However, it remains unknown whether certain types of species are consistently gained or lost across different habitats. Here, we analysed the trajectories of 1827 plant species over time intervals of up to 78 years at 141 sites across mountain summits, forests, and lowland grasslands in Europe. We found, albeit with relatively small effect sizes, displacements of smaller- by larger-ranged species across habitats. Communities shifted in parallel towards more nutrient-demanding species, with species from nutrient-rich habitats having larger ranges. Because these species are typically strong competitors, declines of smaller-ranged species could reflect not only abiotic drivers of global change, but also biotic pressure from increased competition. The ubiquitous component of turnover based on species range size we found here may partially reconcile findings of no net loss in local diversity with global species loss, and link community-scale turnover to macroecological processes such as biotic homogenisation

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world\u27s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Global maps of soil temperature.

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Biogeography of intraspecific trait variability in matgrass (Nardus stricta): High phenotypic variation at the local scale exceeds large scale variability patterns

International audienc

Festuco-Brometea-Gesellschaften im Siebenbürgischen Becken (Rumänien) : eine vorläufige Übersicht zu Syntaxonomie, Ökologie und Biodiversität

The Transylvanian Plateau in Romania is well known to host large areas of a variety of dry grassland types, still traditionally managed by low-intensity mowing or grazing. While this natural heritage is now under threat from changes in agricultural practices, the diversity of Transylvanian dry grasslands is still little understood. There is a lack of both field data sampled with standardised methods and a syntaxonomic treatment with modern statistical methods and supra-regional perspective. Therefore, the European Dry Grassland Group (EDGG) carried out its first international Research Expedition in Transylvania 2009 to study syntaxonomy, vegetation-environment relationships, and biodiversity patterns of these communities. In various locations across Transylvania, we sampled 10-m² vegetation plots (n = 82) and nested-plot series from 0.0001 m² to 100 m² (n = 20), including all vascular plant, bryophyte, and lichen species, as well as structural and soil data. The vegetation classification was carried out with modified TWINSPAN, followed by determination of diagnostic species with phi values and a small-scale re-assignment of relevés with the aim of crispness maximisation. Both TWINSPAN and ordination revealed three major groups of syntaxa, which were matched to three orders from the class of basiphilous dry grasslands, Festuco-Brometea, represented by one alliance each: rocky dry grasslands (Stipo pulcherrimae-Festucetalia pallentis: Seslerion rigidae); xeric grasslands on deep soils (Festucetalia valesiacae: Stipion lessingianae) and meso-xeric grasslands on deep soils (Brachypodietalia pinnati: Cirsio-Brachypodion pinnati). We accepted nine association-level units plus two that potentially merit association status but were only represented by one relevé each. Most of the units could be identified with one or several previously described associations. To support nomenclatural stability, we provide a nomenclatural revision and designate nomenclatural types where previously there were none. Further, we used DCA ordination and analysis of variance to determine the main environmental drivers of floristic differentiation and to determine ecological and structural differences between the vegetation types. The strongest differentiation occurred along the aridity gradient with the dense, particularly diverse stands on more or less level sites on the one hand (Brachypodietalia pinnati) and the more open, less diverse stands on steep south-facing slopes on the other end of the gradient (Stipo pulcherrimae- Festucetalia pallentis, Festucetalia valesiacae). The two xeric orders were then separated along the second DCA axis, with the Stipo pulcherrimae-Festucetalia pallentis inhabiting the stone-rich sites at higher altitudes while the Festucetalia valesiacae occur on soft, deep substrata at lower altitudes. The analysed dry grassland communities have extraordinarily high -diversity at all spatial scales for all plants and for vascular plants, but are relatively poor in bryophytes and lichens. Some formerly mown stands of the Festuco sulcatae-Brachypodietum pinnati (Brachypodietalia pinnati) are even richer in vascular plant species than any other recorded vegetation type worldwide on the spatial scales of 0.1 m² (43) and 10 m² (98); the respective relevés are documented here for the first time. Also, the b-diversity of the grasslands was unexpectedly high, with a mean z-value of 0.275. Despite its limited extent, the methodological thoroughness of this study allows us to shed new light on the syntaxonomy of dry grasslands in Romania and to raise the awareness that Transylvania still hosts High Nature Value grasslands that are bio - diversity hotspots at a global scale but at the same time are highly endangered through changes in agricultural practices.Das Siebenbürgische Becken ist bekannt als Heimat verschiedener Typen von Trockenrasen, die eine große Fläche einnehmen. Diese Grasländer werden zum großen Teil noch sehr traditionell durch exten sive Beweidung oder Mahd genutzt. Während dieses Naturerbe derzeit durch gravierende Land nutzungs änderungen gefährdet ist, ist wenig über die Vielfalt der Siebenbürgischen Trockenrasen bekannt. Es fehlten standardisiert erhobene Daten sowie syntaxonomische Auswertungen mit modernen statistischen Methoden aus einem überregionalen Blickwinkel. All diese Tatsachen zusammen motivierten die European Dry Grassland Group (EDGG) dazu, ihre erste internationale Forschungsexpedition im Jahre 2009 nach Siebenbürgen durchzuführen, um die Syntaxonomie, Ökologie und Biodiversitätsmuster der Siebenbürgischen Trockenrasengesellschaften zu untersuchen. In verschiedenen Gebieten Siebenbürgens fertigten wir sowohl Vegetationsaufnahmen auf 10 m²-Flächen (n = 82) als auch geschachtelte Aufnahmeserien auf Flächen von von 0,0001 m² bis 100 m² Größe (n = 20) an. In den Aufnahmenflächen wurden Gefäßpflanzen, Moose und Flechten erhoben sowie Untersuchungen der Vegetationsstruktur und Bodeneigenschaften durchgeführt. Die Vegetationsklassifikation erfolgte mit Hilfe einer modifizierten TWINSPAN-Analyse. Diagnostische Arten wurden durch Phi-Werte nach einer Neuzuordnung weniger Aufnahmen mit dem Ziel der Maximierung der Trennschärfe ermittelt. Sowohl durch TWINSPAN als auch durch die Ordninationanalyse wurden drei Hauptgruppen von Syntaxa ermittelt, die je einer Einheit innerhalb von drei Vegetationsordnungen der Klasse der basiphilen Trockenrasen (Festuco-Brometea) zugeordnet wurden: Felstrockenrasen (Stipo pulcherrimae-Festucetalia pallentis: Seslerion rigidae); Trockenrasen auf tiefgründigem Boden (Festucetalia valesiacae: Stipion lessingianae) und Halbtrockenrasen auf tiefgründigen Böden (Brachypodietalia pinnati: Cirsio-Brachypodion pinnati). Wir akzeptierten neun Vegetationseinheiten auf der Ebene von Assoziationen sowie zwei weitere mögliche Assoziationen, die aber nur durch jeweils eine Vegetationsaufnahme repräsentiert waren. Die meisten Einheiten konnten einer oder mehreren bereits beschriebenen Assoziationen zugeordnet werden. Um nomenklatorische Stabilität zu erreichen, führten wir eine nomenklatorische Revision der Gesellschaften durch und benannten neue nomenklatorische Einheiten. Weiterhin führten wir eine Gradientenanalyse (DCA) und Varianzanalysen durch, um den Zusammenhang zwischen Umweltfaktoren und Vegetationsunterschieden zu ermitteln sowie ökologische und strukturelle Unterschiede zwischen den Vegetationstypen zu analysieren Die stärksten floristischen Unterschiede wurden entlang eines Trockheitsgradienten mit dichter, besonders artenreicher Vegetation auf weniger stark geneigten Flächen auf der einen (Brachypodietalia pinnati) und offener, weniger artenreicher Vegetation an steilen Südhängen auf der anderen Seite des Gradienten (Stipo pulcherrimae-Festucetalia pallentis, Festucetalia valesiacae) ermittelt. Diese zwei Ordnungen differenzierten entlang der zweiten DCA-Achse, wobei die Stipo pulcherrimae-Festucetalia pallentis-Gesellschaften auf gesteinsreichen Flächen in höheren Lagen und die Festucetalia valesiacae- Gesellschaften auf tiefgründigen Böden in niedrigeren Lagen vorkommen. Die untersuchten Trockenrasengesellschaften besaßen über alle räumlichen Skalen hinweg eine außergewöhnlich hohe b-Diversität, bezogen auf die Gesamtartenzahl und die Gefäßpflanzen, aber sie waren arm an Moosen und Flechten. Für einige der früher gemähten Flächen der Festuco sulcatae-Brachypodietum pinnati-Gesellschaft (Brachypodietalia pinnati) wurde sogar die höchste Gefäßpflanzenvielfalt weltweit auf den Skalen 0,1 m² (43 Arten) und 10 m² (98 Arten) gemessen; die jeweiligen Vegetationsaufnahmen werden hier zum ersten Mal präsentiert. Auch die b-Diversität des Graslandes war unerwartet hoch mit einem mittleren z-Wert von 0.275. Zusammenfassend lässt sich sagen, dass unsere Studie durch die methodische Gründlichkeit trotz ihres begrenzten Ausmaßes ein neues Licht auf die Syntaxonomie der rumänischen Trockenrasen wirft. Weiterhin stärkt sie das Bewusstsein, dass Siebenbürgen immer noch Grasland von sehr hohem Schutzwert besitzt, das global betrachtet einen Hotspot der Biodiversität bildet, aber durch Landnutzungsänderungen stark gefährdet ist

Classification of European beech forests : a Gordian Knot?

Questions: What are the main floristic patterns in European beech forests? Which classification at the alliance and suballiance level is the most convincing?. Location: Europe and Asia Minor. Methods: We applied a TWINSPAN classification to a data set of 24 605 relevés covering the whole range of Fagus sylvatica forests and the western part of Fagus orientalis forests. We identified 24 ‘operational phytosociological units’ (OPUs), which were used for further analysis. The position of each OPU along the soil pH and temperature gradient was evaluated using Ellenberg Indicator Values. Fidelity of species to OPUs was calculated using the phi coefficient and constancy ratio. We compared alternative alliance concepts, corresponding to groups of OPUs, in terms of number and frequency of diagnostic species. We also established formal definitions for the various alliance concepts based on comparison of the total cover of the diagnostic species groups, and evaluated alternative geographical subdivisions of beech forests. Results: The first and second division levels of TWINSPAN followed the temperature and soil pH gradients, while lower divisions were mainly geographical. We grouped the 22 OPUs of Fagus sylvatica forests into acidophytic, meso-basiphytic and thermo-basiphytic beech forests, and separated two OPUs of F. orientalis forests. However, a solution with only two ecologically defined alliances of F. sylvatica forests (acidophytic vs basiphytic) was clearly superior with regard to number and frequency of diagnostic species. In contrast, when comparing groupings with three to six geographical alliances of basiphytic beech forests, respectively, we did not find a strongly superior solution. Conclusions: We propose to classify F. sylvatica forests into 15 suballiances – three acidophytic and 12 basiphytic ones. Separating these two groups at alliance or order level was clearly supported by our results. Concerning the grouping of the 12 basiphytic suballiances into ecological or geographical alliances, as advocated by many authors, we failed to find an optimal solution. Therefore, we propose a multi-dimensional classification of basiphytic beech forests, including both ecological and geographical groups as equally valid concepts which may be used alternatively depending on the purpose and context of the classification.</p

Climate and socio- economic factors explain differences between observed and expected naturalization patterns of European plants around the world

The number of naturalized (i.e. established) alien species has increased rapidly over recent centuries. Given the differences in environmental tolerances among species, little is known about what factors determine the extent to which the observed size of the naturalized range of a species and hence the extent to which the observed richness of naturalized species of a region approach their full potential. Here, we asked which region- and species-specific characteristics explain differences between observed and expected naturalizations. Location: Global. Time period: Present. Major taxa studied: Vascular plants. Methods: We determined the observed naturalized distribution outside Europe for 1,485 species endemic to Europe using the Global Naturalized Alien Flora (GloNAF) database and their expected distributions outside Europe using species distribution models. First, we investigated which of seven socio-economic factors related to introduction pathways, anthropogenic pressures and inventory effort best explained the differences between observed and expected naturalized European floras. Second, we examined whether distributional features, economic use and functional traits explain the extent to which species have filled their expected ranges outside Europe. Results: In terms of suitable area, more than 95% of expected naturalizations of European plants were not yet observed. Species were naturalized in only 4.2% of their suitable regions outside of Europe (range filling) and in 0.4% of their unsuitable regions (range expansion). Anthropogenic habitat disturbance primarily explained the difference between observed and expected naturalized European floras, as did the number of treaties relevant to invasive species. Species of ornamental and economic value and with large specific leaf area performed better at filling and expanding beyond their expected range. Main conclusions: The naturalization of alien plant species is explained by climate matching but also by the regional level of human development, the introduction pressure associated with the ornamental and economic values of the species and their adaptation to disturbed environments