Idoia Biurrun

The role of alien plants in the natural coastal vegetation in central-northern Spain

Alien plants in coastal habitats and their influence on natural vegetation are studied. After 5 years working on this subject in the Basque Country and surrounding areas, a number of results from the coastal ecosystems are presented. These ecosystems are one of the most threatened and affected by the invasion of alien plants, especially shore dunes, saltmarshes and cliffs. These kinds of habitats, especially the dunes, experience significant pressure from human activities which favours the expansion of some of these species: Arctotheca calendula, Sporobolus indicus and Oenothera spp. The presence and abundance of these invasive plants and others such as Baccharis halimifolia, Cortaderia selloana, Spartina patens and Carpobrotus edulis in the plant communities in an area between the French border and the western part of the region of Cantabria have been studied. The degree of invasion of each plant in each syntaxonomic unit has been analysed.

Invasion patterns in riparian habitats: The role of anthropogenic pressure in temperate streams

The riparian flora and the level of invasion in the rivers of the Cantabric watershed in Spain were studied in relation to the ecological status and the anthropogenic pressure. The level of invasion was also analyzed in different riparian habitats: forests, river bars and man-made slopes. For this purpose, 18 sites were sampled and a list of native and alien plant species was made along a 100-m strip at each site. The habitat/s where alien species were found and their abundance per habitat and in the total area were also indicated. Out of 112 alien taxa found, 51 were classified as invasive. Exotic plants native to America were the most common (35%). The level of invasion was significantly higher in the sampling sites subject to high levels of hydrological and morphological disturbances, proxies of the anthropogenic pressure. River bars and man-made slopes supported similar number of alien plant species, higher than forests. We suggest that disturbance in river banks should be minimized as much as possible in order to diminish the risk of invasion.

Assessing the level of plant invasion: A multi-scale approach based on vegetation plots

Recent studies highlight the importance of selecting the appropriate scale and indices of invasion level for evaluating the abundance and impact of alien plants. Our survey considers the use of vegetation plot databases compared with floristic checklists to address invasion patterns regarding alien–native relationships across vegetation types by means of a multi-scale approach. We analysed the alien–native richness relationship in 1077 vegetation plots from the Basque Country (N. Spain) at ecosystem level and phytosociological class and alliance levels. According to our results, the alien species richness (Alo)–native species richness (Nat) relationship is variable and depends not only on the scale but also on the vegetation type. In contrast with other multi-scale approaches, no negative correlation has been detected at any studied level. The strong correlation existing between plot number and cumulative Alo and cumulative Nat highlights the constraints of using checklists to generalize invasion patterns. Our results demonstrate that the combined use of both relative alien species richness and relative alien species cover facilitates the understanding of invasion patterns across plant communities at different scales. In addition to climate, disturbance and propagule pressure, habitat type proved to be an important filter for alien species, capable of explaining such patterns.

European Red List of Habitats : Part 2. Terrestrial and freshwater habitats

The first ever European Red List of Habitats reviews the current status of all natural and semi-natural terrestrial, freshwater and marine habitats and highlights the pressures they face. Using a modified version of the IUCN Red List of Ecosystems categories and criteria, it covers the EU28, plus Iceland, Norway, Switzerland and the Balkan countries and their neighbouring seas. Over 230 terrestrial and freshwater habitats were assessed. The European Red List of Habitats provides an entirely new and all embracing tool to review commitments for environmental protection and restoration within the EU2020 Biodiversity Strategy. In addition to the assessment of threat, a unique set of information underlies the Red List for every habitat: from a full description to distribution maps, images, links to other classification systems, details of occurrence and trends in each country and lists of threats with information on restoration potential. All of this is publicly available in PDF and database format (see links below), so the Red List can be used for a wide range of analysis. The Red List complements the data collected on Annex I habitat types through Article 17 reporting as it covers a much wider set of habitats than those legally protected under the Habitats Directive.

Formalized classification of European fen vegetation at the alliance level

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. 29 049 vegetation-plot records of fenswere selected fromdatabases 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. The following alliances were defined: Caricion viridulo-trinervis (sub-halophytic 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 (Sphagnumbrown-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-borealalpine 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 andmoderately rich fens, to poor fens and dystrophic hollows.

Relationships between syntaxonomy ofThero-Salicornietea and taxonomy of the generaSalicornia andSuaeda in the Iberian Peninsula

This paper deals with the syntaxonomy of the classThero-Salicornietea in the Iberian Peninsula, falling particularly upon the significance that taxonomy of the generaSalicornia andSuaeda has on it. Three alliances were differentiated, two Atlantic and one Mediterranean. The Atlantic ones wereSalicornion dolichostachyo-fragilis, with four associations grouping slikke communities with tetraploid glasswort (Salicornia) species, andSalicornion europaeo-ramosissimae, with three associations of schorre with generally diploid glasswort species. The Mediterranean allianceSalicornion patulae had six associations distributed both in coastal (southern and eastern coasts) and inland salt marshes. A complete syntaxonomy of the class, maps of the distribution of its associations and tables summarizing their floristic composition are also provided.

Ecology and Conservation of Steppes and Semi-Natural Grasslands

Abstract Palaearctic grasslands encompass a diverse variety of habitats, many of high nature value and vulnerability. The main challenges are climate-change, land-use change, agricultural intensification and abandonment. Many measures are in place to address these challenges, through restoration and appropriate management, though more work is necessary. We present eight studies from China/Germany, Greece, Kazakhstan, Russia and Ukraine. The papers cover a wide range of grassland and steppe habitats and cover vegetation ecology, syntaxonomy and zoology. We also conducted a systematic search on steppe and grassland diversity. The greatest number of studies was from China, followed by Germany and England. We conclude that the amount of research being carried out on Eurasian grasslands is inadequate considering their high levels of biodiversity and vulnerability. We hope to encourage readers to address current major challenges, such as how to manage grasslands for the benefit of diverse taxa, to ensure that conservation initiatives concentrate on sites where there is good potential for success and for the generation of realistic and viable conservation strategies.

Marcescent Forests of the Iberian Peninsula: Floristic and Climatic Characterization

Forests dominated by marcescent oak species represent the transition between deciduous forests adapted to rainy summers and cold winters, on the one hand, and evergreen sclerophyllous Mediterranean forests. In the Iberian Peninsula marcescence is shown by some oak species, including Quercus pubescens, Q. pyrenaica, Q. faginea and Q. canariensis; it suggests an old evergreen habit forced to become deciduous by the cold winters. In this paper we analyse the floristic diversity of marcescent forests in the Iberian Peninsula and their proportion of evergreen broad-leaved and sub-Mediterranean species, and relate them to climatic conditions. This analysis uses 494 phytosociological releves from the Information System of Iberian and Macaronesian Vegetation (SIVIM) and the BIOVEG data-bases. The data-set was submitted to an agglomerative clustering, which produced four clusters. An NMDS gradient analysis was also applied, in order to assess the relationship between the clusters and bioclimatic variables. The hierarchical and syntaxonomical classifications show a high correspondence, as reflected in the dominance of different Quercus species in each cluster. Quercus broteroi and Q. canariensis forests show a higher proportion of evergreen broad-leaved species, while Q. pubescens and Q. faginea forests are characterized by sub-Mediterranean species. As for climatic relationships, Q. broteroi and Q. canariensis forests present the highest values of thermicity (It) and the lowest values of the ombrothermic (Io2) index. These values indicate their Mediterranean, thermophilous character, which in turn is related to their high proportions of evergreen broad-leaved species. As a conclusion, it can be stated that marcescence is not related to evergreeness, the latter being linked to mediterraneity. Therefore, the idea of considering marcescence as a residual feature of ancient evergreen laurophyll forests is not supported by our results. Those marcescent forests, particularly the basophilous ones, are related to the sub-Mediterranean floristic element.

Perennial nitrophilous vegetation of the northern Iberian Peninsula

. The syntaxonomy of the perennial nitrophilous vegetation assigned to the Artemisietea vulgaris of the northern part of the Iberian Peninsula (Basque Country and surrounding areas) was revised. The study area is of biogeographic importance due to its transitional character - here, the ruderal vegetation of the Mediterranean and that of temperate Europe meet. Numerical ordination of the communities was performed in order to reveal systematic relations between the syntaxa. Two subclasses, Artemisienea vulgaris and Onopordenea, encompassing five orders, Convolvuletalia, Galio-Alliarietalia, Artemisietalia, Onopordetalia, Carthametalia lanati, and seven alliances with 12 associations and two rankless communities were distinguished.

The challenge of abandonment for the sustainable management of Palaearctic natural and semi-natural grasslands

Abstract Disturbance by biomass removal is a crucial mechanism maintaining the diversity of Palaearctic grasslands, which are unique biodiversity hotspots. The century-long traditional land use of mowing, grazing and burning, has been fundamentally changed in many parts of the Palaearctic. Due to socio-economic changes, large areas of former pastures and meadows have been abandoned, leading to a succession towards secondary scrublands or forest and the encroachment of competitor grass species, all leading to a decrease in biodiversity. Here we report the causes and consequences of the cessation of traditional grassland management regimes, provide strategies for reducing the impact of abandonment and consider these from the perspective of sustainability. We consider the possibilities for initiating sustainable management regimes in the contemporary socio-economic environment, and discuss the prospects and limitation of alternative management regimes in the conservation of grassland biodiversity. These themes are also the core topics of this Special Feature, edited by the EDGG. We hope that this Special Feature will encourage steps towards more sustainable strategies for the conservation of Palaearctic grasslands and the integration of the sustainability perspective into their conservation.