Scale-dependent plant diversity in Palaearctic grasslands: a comparative overview

Here we present an extensive overview of plant diversity values in Palaearctic grasslands for seven standard grain sizes from 0.0001 to 100 m². The data originate from 20 studies, including the Field Workshops of the Eurasian Dry Grassland Group (EDGG), ranging geographically from Spain in the west to Siberia in the east, from Sicily in the south to Estonia in the north and from the sea coast up to 3100 m a.s.l. The majority of data is from dry grasslands (Festuco-Brometea, Koelerio-Corynephoretea, Cleistogenetea squarrosae), but there are also some mesic, wet, saline, acidic, alpine and Mediterranean grasslands included. Among others, we compiled data from 1795 1-m², 1109 10-m² and 338 100-m² plots. In all cases we present mean, minimum and maximum richness for the seven grain sizes, plus, in cases where also terricolous bryophytes and lichens had been recorded, the same values for total “plant” species richness, non-vascular plant species richness and fraction of non-vascular plants. The maximum richness values were 82, 101 and 134 for all “plants”, and 79, 98 and 127 vascular plants at grain sizes of 1 m², 10 m² and 100 m², respectively (all in Transylvania, Romania). Our overview comprises new, hitherto unpublished world records of vascular plant species richness at the scales of 0.0001 m² (9) and 0.001 m² (19, both shoot presence), from meso-xeric, basiphilous grasslands in Navarre, Spain, which is much higher than the previously known maxima. The highest values of non-vascular plant richness at 1 m², 10 m² and 100 m², respectively, were 49, 64 and 64, respectively (all in Sedo-Scleranthenea communities of Öland, Sweden, and Saaremaa, Estonia). In general, the dry, alpine and Mediterranean grasslands were much richer than the studied mesic, wet or saline grasslands at any spatial scale. The presented set of mean, minimum and maximum values and their metadata is publically available and will be continuously updated. These data can serve as a reference of “normal” richness, both in fundamental and applied research. To facilitate the application, we provide an easy formula based on the power-law species-area relationship that allows the estimation of richness values at intermediate grain sizes not included in our dataset. In conclusion, our data emphasise the role of Palaearctic grasslands as global hotspot of small-scale vascular plant diversity, while at the same time highlighting that in some grassland types also the bryophyte and lichen diversity can be extraordinarily high

ASPIRE : un cadre méthodologique pour l'appréciation du succès des projets d'ingénierie et de restauration écologiques : application à une opération de restauration d'une zone humide d'altitude

The high number of dimensions of ecological engineering and restoration projects contributes to their values but also to their assessment issues. The objective of the ASPIRE (Assessment of Ecological Engineering and Restoration Projects) framework is to provide a tool delivering a global project assessment, while also providing detailed scores for each of its dimensions. ASPIRE is composed of 3 levels: variables, objectives and the project. Variables are measured on the study site. Their values are normalized to range between 0 and 1. Objectives correspond to a variable list, and their score are the weighted mean of variables normalized values. The final project score is the weighted mean of the objectives scores. Scores attributed to variables are relative to references, therefore they can be compared to each other's, and objectives and scores can also be compared to each other's. While being calculated on the same study site measurements, variables and objectives weighting allows highlighting different visions of the project (for instance, from various stakeholders). ASPIRE is illustrated by its application on a mountain wetland restoration project.Du fait de la multiplicité des dimensions des projets de restauration, peu de retours sont réalisés pour évaluer leur réussite. Ces retours sont pourtant nécessaires à l'élaboration de projets futurs plus efficaces. Le cadre méthodologique ASPIRE a pour but de permettre une appréciation globale du projet en s'appuyant notamment sur les variables (mesures prises sur le terrain), les objectifs de la réhabilitation et le projet en lui-même

Recovery of arbuscular mycorrhizal fungi root colonization after severe anthropogenic disturbance: four species assessed in old-growth Mediterranean grassland

[Departement_IRSTEA]Territoires [TR1_IRSTEA]SEDYVIN [Departement_IRSTEA]Territoires [TR1_IRSTEA]SEDYVINInternational audienceArbuscular mycorrhizal fungi (AMF) interact continuously with vegetation and soil, and thus shape the dynamics of plant communities. Yet the recovery of AMF after severe anthropogenic disturbance such as cultivation has rarely been assessed. Here, to determine whether AMF root colonization recovers after such disturbance, we compared AMF root colonization in abandoned fields last cultivated 2, 35 and 150 years ago in the La Crau area (south-eastern France) with that of a grassland several thousands of years old (considered as the reference ecosystem). We measured AMF root colonization of four species (Carthamus lanatus, Carduus pycnocephalus, Brachypodium distachyon and Bromus madritensis) and performed surveys of plant communities and soil chemical properties. AMF root colonization was still significantly lower 35 years after disturbance for one species (B. distachyon) and two years after disturbance for one species (B. madritensis). The main soil chemical properties (soil pH, phosphorus and potassium content) were similar to the reference ecosystem 35 years after disturbance. Average vegetation height and cover recovered after 35 years whereas species richness recovered only on the field abandoned for 150 years. Vegetation composition and structure did not recover in any of the abandoned fields. Our results suggest that recovery of AMF root colonization is very low after a severe anthropogenic disturbance, despite the recovery of soil chemical properties

Végétation, sol et mycorhizes sont-ils résilients à une perturbation majeure d’origine anthropique ?

International audienc

Une approche intégrative (communautés végétales, bactériennes et mycorhiziennes) pour mieux mesurer la résilience des formations végétales.

International audienc

Steppes of Southern Siberia - Experiences from the 6th EDGG Research Expedition to Khakassia, Russia (22 July – 1 August 2013)

The 6th EDGG Research Expedition took place in summer 2013 in the Kuznetsky Alatau Mountains, part of the Altai-Sayanian mountain region (Republic of Khakassia, Russia). A group of 14 scientists from seven countries studied the variety of steppe vegetation in two regions of the "Khakassky" Reserve – Lake Itkul (Shira region) and Podzaploty (Ordzhenikidzevsky region). Standardised sampling procedures including nested-plot series and phytosociological relevés of 10-m2 plots were used to sample steppes of European-Siberian (Festuco-Brometea) and Central Asian (Cleistogenetea squarrosae) types. All terricolous plants present in the plots were sampled, including perennial and annual vascular plants, bryophytes, and lichens. The data will be used for analyses of scale-dependent diversity patterns and species-area relationships, as well as for studying vegetation-environment relationships and performing phytosociological classification

Les populations iséroises de petite massette (Typha minima Hoppe) : suivis et perspectives de restauration

Over the last 3 centuries, the alpine piedmont rivers have been considerably transformed. Among the species present in these impacted environments is the dwarf bulrush (Typha minima Hoppe). Its most important populations are located in the French Alps rivers such as the Arve, Isère or Durance, where it is protected at the national level. As such, after avoidance and reduction, the residual impacts on its populations must be compensated. The restoration of populations of T. minima poses questions to which this article aims at providing some answers. T. minima ecological niche of T. minima on Isère shows that it is not possible to predict the presence of favorable habitats from Isère hydrogeomorphological characteristics. However, our results show that in order to optimize their survival, population transplantations will have to be carried out on benches with gentle slopes at elevation slightly above the average level of the water. Concerning transplantation methods study, early trends suggest that the three types of transplants tested: containers, buckets and bare roots, can lead to the establishment of viable populations, even if containers and buckets give better results the first year.Pour se protéger des crues en montagne, les hommes ont transformé et artificialisé les cours d'eau, avec comme conséquence une perte en surface d'habitats pour la biodiversité. Ainsi, les populations de petite massette (Typha minima Hoppe), plante des berges des cours d'eau, ont régressé de 85 % en un siècle dans les Alpes ! Aujourd'hui, la législation est plus attentive à la préservation de la biodiversité dans le cadre de projets d'aménagement et elle rend obligatoire un certain nombre de mesures permettant de compenser les impacts sur les écosystèmes. Pour les aménageurs du territoire, la restauration de populations de T. minima pose cependant des questions auxquelles cet article apporte des éléments de réponses

Steppes of Southern Siberia - Experiences from the 6th EDGG Research Expedition to Khakassia, Russia (22 July – 1 August 2013)

The 6th EDGG Research Expedition took place in summer 2013 in the Kuznetsky Alatau Mountains, part of the Altai-Sayanian mountain region (Republic of Khakassia, Russia). A group of 14 scientists from seven countries studied the variety of steppe vegetation in two regions of the "Khakassky" Reserve – Lake Itkul (Shira region) and Podzaploty (Ordzhenikidzevsky region). Standardised sampling procedures including nested-plot series and phytosociological relevés of 10-m2 plots were used to sample steppes of European-Siberian (Festuco-Brometea) and Central Asian (Cleistogenetea squarrosae) types. All terricolous plants present in the plots were sampled, including perennial and annual vascular plants, bryophytes, and lichens. The data will be used for analyses of scale-dependent diversity patterns and species-area relationships, as well as for studying vegetation-environment relationships and performing phytosociological classification