Geobotanical survey of wood-pasture habitats in Europe: diversity, threats and conservation

Wood-pasture as land-use is now historical or neglected in most parts of Europe, but still recognizable and widespread as remnant scrub or woodland formation with other than traditional management. Relic wood-pasture sites may be identified using old records or maps or a combination of traits such as the presence of old (veteran) trees, trees with symptoms of former grazing pressure and/or leaf-hay collection, open or partially open grown trees, uneven stocking, irregular site boundaries, patchiness with frequent glades and areas with scattered trees (Surrey Biodiversity Partnership 2008). Where extant, wood-pasture is now often separated from types of forest used exclusively for firewood or timber. Exceptions are reindeer pastoral woodland with birch and pine in subarctic Europe, mountain summer pastures that extend into montane woodlands, and pastoral woodlands and scrublands in parts of Eastern Europe, the Mediterranean and the Balkans, where wood-pastures to some extent retain their traditional usage.

In Central Europe, wood-pasture was common practice until, with the agrarian reforms in the nineteenth century, it was banned almost everywhere, and remained so except in times of destitution. Banning wood-pasture and litter-raking was a consequence of the shortage of wood and timber when the demands of the growing population and industries increased enormously (Behre 2008; Küster 1995; Luick 2009). Wood-pastures in common use formed part of the allmende (common land). Depending on local environment, traditions and needs, wood-pasture in the allmende was grazed by cattle, horses, sheep, pigs, geese and, prohibited first of all, goats. Trees were coppiced or pollarded for firewood, others cut for timber. Leaf-hay was also produced by lopping or shredding trees to feed the animals in late summer and autumn (Ellenberg 1996; Luick 2009; Machatschek 2002). While wood-pasture as part of the allmende did not normally involve regular cycles of pollarding or coppicing, other land-use systems that provided wood, charcoal, grass and even annual crops such as rye incorporated pasturing as part of the regular cycles. In the north-west German Siegerland, the hauberg cycle involved coppice, cereal cultivation, fallow and wood-pasture (Behre 2008; Pott 1990; Pott and Hüppe 1991). To prevent the animals from eating the regrowth of trees, coppices were excluded from grazing for a number of years subsequent to cutting. In recent years, semi-open pasture is being re-introduced in Germany as a conservation concept to preserve the biodiversity of pasture-woodland landscapes (Finck et al. 2002; Gerken et al. 2008). Such concepts use components of traditional farming (wood-pasture or other pastoral systems) and robust breeds, which are kept in a ‘semi-wild’ manner all year round in large grazing sites.

In Britain, wood-pasture commons similar to allmende existed (McAdam 2005; Rackham 2007). They are to be distinguished from fenced parks and non-fenced Forests, both of which were private lands used for gamekeeping, especially of deer (Rackham 2004; Spencer 2002). Game parks have a long tradition in Europe at least since Roman times, whilst Forests were for centuries the hunting grounds of nobles. Thanks to Forests and to similar game reserves and grazed woodlands on the European continent, old-growth woodlands survived in some lowland areas where almost all other woodland was cleared.

In northern Europe, traditional management of forests has frequently been connected with hay-making, such as in the southeast Fennoscandian and Baltic lövängar. Such wooded pastures and meadows have a habitat tradition of 4,000 years or more (Dierßen 1996; Hytönen 1995). Their structure resembles that of weidfeld systems in the mountains of central Europe (Haas and Rasmussen 1993) and similar ones in southern European mountains (Eichhorn et al. 2006; Halstead and Tierney 1998; Loidi 2005). Restoring traditional forest management in nature reserves has been practised, albeit rarely, in western, central and northern Europe (e.g., Losvik 1989).

In Spain and Portugal, pastoral woodlands of the dehesa and montado type are kept as grazing grounds for pigs, cattle and sheep, and locally for deer hunting (Diaz et al. 1997). Iberian pastoral woodlands are estimated at approximately 55,000 km² (Tucker and Evans 1997), of which dehesas (23,000 km²) and montados (7,000 km²) form the major part (Moreno and Pulido 2009). Extensive areas of present-day wood-pasture also exist in Greece and the Balkans (Bergmeier et al. 2004; Grove and Rackham 2003; Horvat et al. 1974), in sites very different in size, vegetation structure and management. According to Papanastasis et al. (2009) the area used for various kinds of agroforestry systems in Greece amounts to more than 20,000 km². In Germany, for comparison, hudewald remnants cover a total area of only 55 km², split in 218 sites of which few are more than 20 ha (Glaser and Hauke 2004). Together with more open pastures with woody component the total area of wood-pasture in Germany has been estimated at 500–1,000 km² (Luick 2009). For lack of national inventories and comparable land coverage definitions, information on the extent of wood-pastures is not available for most European countries.

While Vera (2000) and other authors claim that pre-Neolithic landscapes in west and central Europe comprised wood but also grassland to a large extent, pollen evidence suggests that the opening-up of lowland woodland was initiated by Neolithic man to provide and improve grasslands for livestock: in Britain, north-western Germany and Denmark approximately 6,000 years ago (Behre 2008; Ellenberg 1954; Lang 1994; Rackham 2004), and 7,500 years ago in south-eastern central Europe. In the western Mediterranean there is evidence for agro-silvopastoral systems from Middle Neolithic times (Delhon et al. 2009; Stevenson and Harrison 1992), and presumably earlier in the east (Grove and Rackham 2003). In high-mountain grasslands, pastoralism has been practised since prehistoric times, e.g. in the Alps for 6,000 years (Cernuska et al. 1999; Etienne 1996; Lichtenberger 1994), and longer in the Mediterranean mountains (Hempel 1995; Papanastasis 1998; Pignatti 1983). In antiquity, it attracted the attention of several classical authors (Chaniotis 1991; McNeill 2003). From medieval times until the sixteenth century, the economy of the southern Italian highlands rested on a system of silvopastoralism (McNeill 2003). It opened up montane woodland and led frequently to treeline depression (Stanisci et al. 1996). In the Spanish Central System, municipal dehesas came into being in the Middle Ages through transformation of local forests (Pardo and Gil 2005). For case studies and historical reviews of the human influence on Mediterranean forests in different regions see, e.g., Meiggs (1982), Pignatti (1983), Blanco Castro et al. (1997), Gerasimidis (2005), Loidi (2005), Pardo and Gil (2005), Casals et al. (2009) and Castro (2009). Long-distance pastoralism practices such as transhumance involved shuttling between lowland wood-pastures and high-mountain grasslands, travelling via traditional migration routes such as the cañadas in Spain (Rodríguez Pascual 2001). Transhumance or similar seasonal grazing systems occurred, with fluctuating intensities, throughout the human history of the Mediterranean, and still occur, albeit on a minor scale (McNeill 2003). Formerly, transhumance linked northern Spanish mountains with regions in southern Spain as far as 800 km away. The dehesas of Spain and montados of Portugal formed an important part of the transhumance systems, having been used as pastures in winter and spring. In northern Spain, seasonal grazing with cattle, sheep, goats and horses is still practised using communal pastures. Nowadays, long-distance transhumance works by using railway and road transport (Mayor Lopez 2002). Similarly, in the southern Balkans and in Italy the herds of sheep, goats and cattle roamed the lowland wood-pastures in winter and spring before moving to the mountain summer pastures (Pardini 2009). In the Balkans, up to the beginning of the twentieth century long-distance pastoralism connected mountains and lowlands now separated by national boundaries (Beuermann 1967). Seasonal movements of the magnitude of former times between Balkanic regions ceased over a century ago. ‘Motorized transhumance’, however, still exists in Spain, Italy, Greece and other Mediterranean regions.

To describe wood-pasture types, we use terms well-established in geobotany, but not all of which are known outside their regions of origin. Most of these have local, temporal or regional connotations which may not be fully reflected by our definitions below.

Dehesa Pastoral woodland of the Iberian peninsula dominated by chiefly old-growth sclerophyllous oak-trees, notably Quercus rotundifolia and Q. suber. There are various subtypes but most common are extensive grasslands with 30–100 lopped trees per hectare (Blanco Castro et al. 1997; Grove and Rackham 2003). While dehesa is the Spanish name, the Portuguese equivalent is montado (Castro 2009; Moreno and Pulido 2009).

Forest In its original sense in Britain, woodland or non-wooded unfenced areas where owners kept deer (Rackham 2004, 2007).

Garrigue (garigue, garriga) Mediterranean low scrub formation of browsed evergreen trees and shrubs, sub-shrubs and herbs resulting from long-term grazing, cutting and burning. Greek phrygana, Spanish tomillares and Israelian batha are similar but lack browsed or wind-shorn trees and are hence not dealt with in this paper.

Hudewald (hutewald) Pastoral woodland dominated by tall old-growth oaks (Quercus petraea, Q. robur), beech (Fagus sylvatica) hornbeam (Carpinus betulus) or other deciduous trees, often with pollarded or shredded, but not coppiced trees.

Kratt (krattskogar) Deciduous coppiced woodland dominated by oaks (Quercus petraea, Q. robur) in northern central Europe and in southern Fennoscandia.

Lövängar Fennoscandian deciduous or semi-deciduous low-intensity pastures and meadows with open scrub and groves dominated by Betula spp., Corylus avellana, Fraxinus excelsior and Populus tremula.

Macchia (makija, maquis) Dense sclerophyllous broadleaved or ericaceous Mediterranean scrub derived from coppicing and burning of evergreen Quercion ilicis woodland. A Spanish equivalent is matorral, which is sometimes used in a wider sense (e.g. in the Interpretation Manual of European Union Habitats, European Commission 2007) comprising all open or dense Mediterranean tall scrub.

Park (game park, wildpark) Enclosed woodland or grassland with scattered trees, scrub or groves, used to keep deer or other animals in quantities that require additional feeding. Popular in Europe and beyond since ancient times.

Pseudomacchia Semi-sclerophyllous scrub of the southern Balkans dominated by kermes oak (Quercus coccifera s.l.) resulting from long-term grazing and harvesting of submediterranean Quercetalia pubescentis woodlands (Adamović 1906).

Shibliak (šibljak, Шибљaк) Thermophilous deciduous or semi-deciduous scrub of the Balkans and the Black Sea area resulting from long-term grazing and forest degradation. Shibliak may be composed or dominated by a variety of shrubs, notably Carpinus orientalis, Paliurus spina-christi, Prunus tenella, Quercus trojana, Syringa vulgaris and others (Adamović 1901).

Streuobst Low-intensity orchards with tall standard (Hochstamm) fruit-crop trees close to villages in temperate Europe. Most common are apple, pear, plum and cherry trees. Underneath is usually grassland which is cut or grazed.

Wacholderheide Nutrient-poor grasslands and heathlands interspersed with open scrub of tall, often columnar, Juniperus communis in central and western Europe. It occurs both on calcareous and siliceous soils.

Weidfeld Non-intensive pastures with scrub of Cytisus scoparius and browsed trees, with scattered single- or multi-stemmed Fagus trees, especially in the Schwarzwald (Germany) (Schwabe-Braun 1980).

Wood-pasture occupies a spatial level between ecosystem and landscape, namely that of an ecosystem complex. Ecosystem complexes may be serial, describing a range of plant communities or ecosystems along a successional gradient, or they may be catenal, describing a predictable range of spatially close plant communities (sigmeta). Wood-pastures have elements of both types of ecosystem complexes, and they can only be understood if the ecology and dynamics of the plants and plant communities involved are understood. There is still some way to go to reach this aim. In the framework of this paper our descriptions of the wood-pasture categories have to be brief and general. Specific local types may not always be covered, as our categories cannot describe the full range of intermediates that exist.

This survey is based on geobotanical criteria used for woodlands and grasslands alike, such as climatic zone, altitudinal belt, physiognomy, and dominant species. The major bioclimatic zones in Europe are boreal, meaning the northern conifer-dominated taiga zone, nemoral, comprising the temperate and submeridional broadleaved forest zone, and meridional for the sclerophytic Mediterranean forest zone (Schroeder 1998). Hemiboreal (or boreonemoral), with its deciduous and coniferous woodlands, is the transition zone between the first two, and submeridional, with its chiefly thermophytic deciduous woodlands, between the temperate and the meridional zone. The wooded altitudinal belts are lowland, colline, submontane, montane, altimontane. In the meridional zone the altitudinal belts thermo-, meso-, supra- and oro-mediterranean are arranged using criteria of temperature and distance from coast. For further characteristics see Table 1.

Hemiboreal and boreal wood-pastures

Nemoral old-growth wood-pastures

Nemoral scrub and coppice wood-pastures

Meridional old-growth wood-pastures

Meridional scrub and coppice wood-pastures

Grazed orchards

Where grassland and woodland are kept apart their margins are well-defined and the ecotone is narrow, in contrast to the margins of wood-pasture which are wide, indistinct and not always identifiable. In patchy wood-pastures the wood-grassland ecotone forms a major part of the entire area of wood-pasture. High ecotone proportion is the key factor for high species and niche densities of pastoral woodlands (Bergmeier 2004). Wood-pasture provides a wide range of light and shade conditions, nutrient-poor and small-scale nutrient-rich sites and a certain low level of disturbance.

Old trees, rare in commercial forests and plantations, are a common, though often relictual, element in pastoral woodlands. They provide structural qualities common to both primeval and pastoral woodland. Certain beetles associated with primeval woodland and indicating considerable habitat age have been found on senescent trees and deadwood in old-growth, formerly pastoral, woodland in central Europe (Müller et al. 2005). The general diversity of beetles has been shown to be related to the structural diversity of wood-pasture, with positive effects of traditional forest management on the fauna of Carabidae and other groups (Desender et al. 1999; Taboada et al. 2006). Heterogeneity in vertical and horizontal vegetation structure seems to favour snail diversity both at the local and landscape scales (Labaune and Magnin 2002).

Pasture-woodland is of ‘habitat importance’ for at least 37 European bird species, and for 18 species a high proportion of their European populations uses this habitat (Tucker and Evans 1997). The following countries are particularly rich in bird species dwelling in pastoral woodland (in decreasing order, according to Tucker and Evans 1997): Spain, France, Portugal, Turkey, Ukraine, Greece, Romania, Bulgaria, Albania, Croatia, Italy, Poland, Slovakia. Spanish imperial eagles (Aquila adalberti) and woodchat shrikes (Lanius senator) are breeding birds almost exclusive to wood-pasture habitats, with the former restricted to Iberian dehesa. Scops owl (Otus scops), hoopoe (Upupa epops), roller (Coracias garrulus) and wryneck (Jynx torquilla) are also characteristic birds of pastoral woodland with old trees. Dehesas and montados are also important habitats for carnivorous mammals such as lynx (Lynx pardinus, a priority species of Annex II of the Habitats Directive), genet (Genetta genetta) and mongoose (Herpestes ichneumon).

Among vascular plants, there is a trend that species more or less common in thermophilous woodland habitats in southern Europe occur in central and northern Europe chiefly in wood-pasture habitats. In the Sava floodplains in Croatia, about 300 plant species (as well as 238 bird species, of which 134 breeding) were found on species-rich pastures and in pasture-woodland. Many of these are threatened and red-listed in central Europe (Poschlod et al. 2002). At a European scale, species that are more or less exclusive to pastoral woodland are poisonous or distasteful herbs, such as peonies (Paeonia broteri, P. clusii, P. coriacea, P. mascula s.l., P. officinalis s.l., P. parnassica, P. peregrina, P. tenuifolia, some of which narrow endemics and taxa listed in Annex II of the Habitats Directive), hellebores (Helleborus bocconei, H. foetidus, H. odorus, H. viridis agg.), Asphodelus albus, Dictamnus albus, Melittis melissophyllum and Veratrum nigrum. These are species of chiefly southern European distribution which are moderately thermophilous and shade-tolerant and sufficiently protected from grazing animals by poisonous chemicals. They may be gregarious in grazed woodland as well as in pastures with few trees left.

Threats to wood-pasture habitats result primarily from changes in traditional land-use practices caused by overall social and economic change in rural landscapes. Such changes may go two different ways: intensification of livestock rearing and thus higher stocking levels, or land abandonment followed by loss of small-scale habitat diversity. As for other non-intensively used habitats, agricultural expansion and intensification, urbanization and road construction have led to increased fragmentation of wood-pasture habitats. More specific problems are: