Volume 14 (2015): Edizione 1 (June 2015)

Most semi-natural open habitats in Europe have been traditionally maintained by anthropogenic activities, such as grazing or mowing, preventing the establishment of woody vegetation. These habitats harbour a remarkably rich biodiversity in terms of both plant and animal species, but are also highly threatened, mainly by agricultural intensification and land abandonment. With this Editorial we introduce a Special Issue initiated by the European Dry Grassland Group (EDGG) at the Open Landscapes Conference (Hildesheim, 2013) and the 11th European Dry Grassland Meeting (Kulikovo Pole, 2014). We aim to give a short introduction to the current conservation status, significance and research of semi-natural open habitats in Europe and present the collected articles of the Special Issue. These papers cover a wide range of different semi-natural open habitats, including wood-pastures, heathlands, steppes, semi-dry and dry grasslands across the Palearctic region and address issues related to the assessment methods, threats, management and restoration of these habitats. We conclude that, in order to ensure their conservation and to monitor the changes in open habitats, integrative approaches are needed that take into account not only vegetation records, but also multiple animal taxa, abiotic factors, management practices, ecosystem services and modelling simulations for anticipating possible future scenarios. We also recommend that decision-makers should support actions to conserve open habitats in Europe by addressing such major challenges as the encroachment of woody vegetation. We are convinced that the present Special Issue will contribute to a better understanding of ecosystem functions and support the biodiversity conservation and management of semi-natural open habitats.

Orthopterans are well known to represent the majority of insect biomass in many grassland ecosystems. However, the verification of a relationship between the traditional descriptors of orthopteran assemblage structure and plant community patterns is not straightforward. We explore the usefulness of the concept of life forms to provide insights on such ecosystem level relationship. For this purpose, thirty sample sites in semi-natural calcareous grasslands were classified according to the relative proportion of dominant herbaceous plant life forms. Orthopteran species were grouped in four categories, based on the Bei-Bienko’s life form categorization. The association among plant communities, orthopteran assemblages and environmental factors was tested by means of canonical correspondence analysis. Orthoptera groups were found to be associated with distinct plant communities, also indicating the effect of vegetation change on orthopteran assemblages. In particular, geobionta species were associated with all the most disturbed plant communities, while chortobionta and thamnobionta seemed to be dependent on better preserved grassland types. Therefore, the use of life forms could help informing on the relationships of orthopteran assemblages with grassland conservation state. Information on such community relationships at the local scale could also assist managers in the interpretation of habitat change maps in terms of biodiversity changes.

Wood-pastures are important for their open-ground biodiversity and for the old trees they contain. However, younger trees to replace the current generation of old trees are often scarce, a potential threat to the future of the habitat mosaic and of species dependent on the trees. A simple model was used to illustrate how many younger trees might be expected under different assumptions of desired final density of old trees and rates of loss as trees age for an oak-dominated wood-pasture. From these the overall canopy cover of the landscape was estimated under an active pollarding regime and where the trees grow to full crown size. Canopy cover was often five times as great under full crown as under a pollarding regime; much of the canopy cover was in the younger (often missing) cohorts. The openness of current wood-pastures is in part a consequence of the absence of a sustainable tree population structure. Some protected sites may be too small to allow space for the missing generation of trees and at the same time retain current levels of openness. Analogies between current wood-pasture structures and ‘natural wood-pastures’ of the pre-Neolithic era must take account of the missing generations of trees.

The region of Tarnava Mare in Southern Transylvania contains extensive semi-natural open landscapes maintained by predominantly low-intensity farming, which is widespread in Romania and indeed many areas of Eastern Europe. Threats to these species-rich habitats from agricultural intensification and land abandonment have been increasing in recent years, to a large extent linked with Romania’s accession to the EU in 2007. At the same time, however, the opportunities for biodiversity conservation in the area have expanded. In 2008, the region became a Site of Community Importance (SCI) as part of the Natura 2000 network, and farmers have applied agri-environment schemes as part of the EU Common Agricultural Policy since 2006. Furthermore, the Tarnava Mare region has been the location of several EU and nationally funded projects combining research, practical and information measures. In this article, we review these various instruments from the practical perspective of an NGO that has been working since 2004 to support High Nature Value farmland and rural communities in this region. We focus on three major support measures - agri-environment schemes, Natura 2000, and publicly funded conservation projects - and consider their effects individually and collectively. We conclude that the presence of multiple instruments can have synergistic effects on the conservation of semi-natural open habitats such as HNV farmland, and that this overlap provides a certain amount of resilience: if one instrument fails, another may fill the gap. Cross-cutting projects combining research with activities to tackle the “problem” of the socio-economic undesirability of low-intensity farming as well as the “symptom” of the loss of HNV farmland are also particularly important in this context.

Recreational activity has a significant impact on the Priol’khonie steppes and forest steppes, which are part of the Pribaikalskyi National Park (western coast of Lake Baikal, Russia). The aim of this investigation is the assessment of different landscapes’ values for the provision of ecosystems functions and services. To meet these objectives, fieldwork was conducted in the Priol’khonie steppes and forest steppes during the summer of 2013. The function of phytomass formation was considered for different land-cover types identified in the area, and the above-ground phytomass and inter-rill erosion were measured. The level of landscape degradation was estimated and draft maps of phytomass stocks and vulnerability to soil erosion of the investigated area were compiled. To show the dependence between the studied ecosystem functions and the ecosystem services provided by them, a scoring of the latter was made. It was found that characteristics of ecosystem functions varied significantly in the steppes of the Priol’khonie.

Recently, anthropogenic fires in protected areas have become more frequent. I studied the response of the spider community after an extensive summer fire in the ‘Striltsivskyi Steppe’ Reserve in eastern Ukraine. A total of 117 spider species was found in the pre-fire period, 40 species were registered in the first and 89 species in the third post-fire year. Herb-dwelling spiders began to colonize burnt plots in July, when juveniles of the new generation began dispersing. In September, their abundance was similar to that of undisturbed steppe and within three years, the spider assemblages recovered almost completely. Cursorial ground-dwellers in the first post-fire year decreased in species richness and increased in activity density. In the third year, their species diversity and activity density became much higher than in control plots. Some xerophilous species benefited from the fire. Litter dwellers are extremely vulnerable. During the three post-fire years, their numbers and diversity did not recover. Some rare species with a patchy geographical distribution disappeared from the local fauna. Such a reaction of endangered species is the main restriction on the use of fire as a conservation management. The prerequisite for its implementation is maintaining relevant refuges for threatened species.

We investigated early spontaneous colonisation patterns during semi-dry grassland restoration at two sites in SE Austria. The sites were left to regenerate passively without addition of plant propagules on a former arable field and an apple orchard. The sites were prepared only by ploughing (arable field) or clear cutting (apple orchard) and subsequently mowed annually. We studied whether, four years after project initiation, target species from adjacent semi-dry grasslands had established at the restored sites. We asked: 1) Does passive restoration lead to the establishment of target species? 2) Do abiotic parameters or distance to reference sites explain early colonisation patterns? 3) Do plant traits predict the colonisation success of different species? At each site, we collected data in 4 m × 4 m plots, in which we sampled the vegetation, analysed abiotic parameters (soil potassium- and phosphorus-content, soil-pH, slope) and recorded the minimum distance to the reference site. We tested for correlations between abiotic variables, plant traits and colonisation success. Colonisation patterns were not driven by abiotic soil conditions but rather by nearest distance to the reference sites. In addition, the vegetation developed differently in the former arable field and the apple orchard. Competitive species of the Arrhenatherion and thermophilic ruderal associations dominated the early restoration stage at both sites. Passive restoration of semi-dry grasslands on former agricultural land is unlikely to succeed unless complemented by initial ploughing, nutrient stripping and addition of propagules of rare species.