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1 The Post-Glacial History of Pulsatilla vernalis and Daphne cneorum in Bitcherland, nferred from the Phytosociological Study of Their Current Habitat Author(s): Serge Muller Source: Global Ecology and Biogeography Letters, Vol. 6, No. 2 (Mar., 1997), pp Published by: Wiley Stable URL: Accessed: 16/05/ :11 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Wiley is collaborating with JSTOR to digitize, preserve and extend access to Global Ecology and Biogeography Letters.

2 Global Ecology and Biogeography Letters (1997) 6, The post-glacial history of Pulsatilla vernalis and Daphne cneorum in Bitcherland, inferred from the phytosociological study of their current habitat SERGE MULLER Laboratoire de Phytoecologie, Centre de Recherches Ecologiques, Universite de Metz, le du Saulcy, F57045-Metz, France Abstract. The post-glacial history of Pulsatilla vernalis and Daphne cneorum in Bitcherland is reconstructed by using a phytosociological study of their current habitat. These two species form part of the mesohydric heathland association Daphno cneori- Callunetum. This plant community is characterized by the co-existence of a group of sub-atlantic species and a group with continental affinities which the two species are found. The presence of this same continental floristic assemblage in the sandy pinewoods of Peucedano-Pinetum of central and oriental Europe leads to the conclusion that D. cneorum and P vernalis constitute relict species from the Boreal Period in the Bitche region. During this period, the climatic climax of the area should have consisted of pine forests having approximately similar vegetation to the current easteuropean Peucedano-Pinetum association. The global warming which followed this period caused the replacement of this association of pine forests by an oak association, Luzulo-Quercetum, repressing the semiheliophilic species, among them P vernalis and D. cneorum, to the clearings and edges of these oak forests. These two species were then able to colonize the secondary heaths, created by the over-exploitation of forests since the Middle Ages. The development of intensive forestry practices in the XX century has caused the regression of these two species, which nowadays are found only in the military grounds in Bitche. Key words. Pulsatilla vernalis, Daphne cneorum, heath, Vosges Mountains, phytogeography, phytosociology, continental, Boreal Period, pine forest, oak forest. NTRODUCTON The reconstitution of ancient floristic migrations is usually carried out with the use of vegetation fossils. The study of pollen deposits in the peat-bogs has enabled the identification of different phases of postglacial vegetation which have succeeded in the Massif Vosgien (Hatt, 1937; Janssen et al., 1975; Kalis, 1984; Edelman, 1985). However, this palynological analysis gives relatively little information about the composition and precise structure of past phytocenoses. A phytosociological study of the present vegetation can therefore aid a more precise reconstruction of the past vegetation by showing the biogeographical and ecological affinities of the different plant communities. ndeed, the floristic assemblages of these plant * Nomenclature of species according to Oberdorfer (1990). communities were generally formed in ancient times and have since conserved their socio-ecological affinities (Conard, 1954; Medwecka-Kornas, 1961; Kornas, 1972). Such an approach to the reconstruction of the postglacial history was attempted for two remarkable species present in the region of Bitche, Pulsatilla vernalis* and Daphne cneorum. MATERAL AND METHODS Phytogeographical presentation of the region Bitcherland is an area located in Mid-Europe (Fig. 1); it consists of an assemblage of geomorphological basins, developed on Vosgian sandstone at altitudes of 250 to 300 m and situated in a depression about 100 m lower? 1997 Blackwell Science Ltd 129

3 130 Serge Muller km N atlantic *..continental inlence - influences Fig.. Location of Bitcherland (*) in Mid Europe. Fig. 1. Location of Bitcherland (*) in Mid Europe. than the border of the Lorraine Plateau by which it is delimited in the west. These basins are surrounded in the north, west and south by the Northern Vosges Mountains, whose summits reach altitudes of between 400 and 580 m. The two main basins are those of Bitche and Neunhoffen. These basins have a particularly cold and rigorous climate as opposed to the borders of the Lorraine Plateau and the North of the Alsace Plain. Minimum temperatures in Bitcherland are between 3 and 4?C lower in Summer and 1.5?C lower in Winter compared with neighbouring territories. The number of days with frost is about 110/year and the average rainfall is 900 mm/year (Muller, 1986). Although the Neunhoffen basin is dominated by the forest milieu, that of Bitche is mainly taken up by a military terrain, set up in This terrain serves as a manoeuvre zone for tanks in the west and practice shooting at targets from the periphery or exterior of the military terrain (in the state forest of Hanau) in the east. This firing zone of about 5 km2 is subject to occasional fires. These military activities have made possible the conservation of vast stands of Calluna heaths. The flora of this territory is marked by the presence of a group of sub-atlantic species which dominate the area, particularly in the forests (e.g. Hypericum pulchrum, Holcus mollis, Teucrium scorodonia, Sarothamnuscoparius, Centaurea nemoralis). Certain species among them are very rare in the area (e.g. Lonicera periclymenum, Galium saxatile), while other typically atlantic species (lex aquifolium, Mespilus germanica, Erica cinerea, Ulex sp.) are completely absent. This sub-atlantic element is associated with a group of species with mid-european affinities which are found in forests (e.g. Luzula luzuloides, Calamagrostis arundinacea), on forest edges (e.g. Peucedanum oreoselinum, Polygonatum odoratum, Rubus saxatalis, Carex montana), on heaths (e.g. Genista germanica, Pulsatilla vernalis var. bidgostiana) and on sandy meadows and dunes (e.g. Botrychiu matricariifolium, Dianthus deltoides, Thesium linophyllon, Lychnis viscaria, Helichrysum arenarium, etc.). The peri-alpine species, widespread on the perimeters of the high European mountains (Alps, Pyrenees, Carpathians) are sometimes found in the Bitche region, examples including Daphne cneorum and Arnica montana in the heathlands and Thesium alpinum and Botrychium lunaria in the meadows. Among this assemblage of species, two of them (P vernalis and D. cneorum) deserve particular attention because of their total absence in the rest of the Massif Vosgien. These two species (Fig. 2) were discovered in Bitcherland and the neighbouring German territory of Wasgau by Schultz (1846), who compiled an inventory

4 Post-glacial history of P. vernalis and D. cneorum 131 Fig. 2. The two species studied. (a) Pulsatili v'mrnalis, (b) Daphne cneorumi. of a large number of places. They have regressed since this period and are now only found on the military zone in Bitche (Muller, 1985c). Pulsatilla vernalis is present in this territory in the form of a hillside variation, P vernalis var. bidgostiana (Oberdorfer, 1990), whose nearest locations are situated in the South of Germany in the Regensburg region (Hohenester, 1960; Zielonkowski, 1973). As regards Daphne cneorum, the areas closest to Bitcherland in which the species is found are in the Chatillonnais region (which radiates as far as Commercy), where this species characterizes the thermophilic borders of the calcareous beech woods (Royer, 1971, 1973 ; Rameau, 1974; Parent, 1979). t also appears in Germany in the Schwabische Alb, in the calcareous pine forests (Muller Th., 1980; Witschel, 1986). ts presence in Bitcherland on a siliceous substrate and in hilly heath lands rich in Calluna is quite remarkable and establishes a parallel between the stations of Bitche and those of the Basque country? 1997 Blackwell Science Ltd, Global Ecology and Biogeographl Letters. 6,

5 132 Serge Muller and Poland, where it was found in identical edaphic conditions (Aymonin, 1958, 1959). Methodology of the phytosociological study The phytosociological study of the heaths constituting the current habitat of these two remarkable species was carried out by using the sigmatist method (Guinochet, 1973). t has been integrated into a larger work which includes the analysis of all the vegetation groups in the territory (Muller, 1986). The goal was the analysis of the floristicomposition and biogeographical affinities of these vegetation groups. About 100 releves of the vegetation communities of heathlands were carried out on homogenous surfaces of 100 m2. The statistical treatment of these data allowed the definition of the vegetation groups which were then compared with bibliographical data. RESULTS The two species, Pulsatilla vernalis and Daphne cneorum, are strictly connected to one heathland plant community, which was described under the name of Daphno cneori-callunetum (Muller, 1985a, 1986, 1988). This association presents a combination of species with diverse phytosociological and ecological affinities (cf. Table 1). (1) A group of thermophilic species: Anthericum liliago, Festuca guestfalica, Peucedanum oreoselinum, Avena pratensis, Polygonatum odoratum, Carex montana, Genista germanica, Galium boreale, Serratula tinctoria, Thymus serpyllum, Daphne cneorum, Pulsatilla vulgaris, P vernalis var. bidgostiana, etc. (2) A group of semi-hygrophilic species: Molinia caerulea, Pteridium aquilinum, Frangula alnus, Stachys officinalis, Succisa pratensis, etc. (3) A group of oligotrophic grassland species: Campanula rotundifolia, Hieracium pilosella, Pimpinella saxifraga, Luzula campestris, Euphorbia cyparissias, Achillea millefolium as well as certain acidoclines such as Agrostis capillaris, Veronica officinalis, and Rumex acetosella. (4) A group of heathland species: Calluna vulgaris, Sarothamnus scoparius, Genistapilosa, Viola canina, Danthonia decumbens, Potentilla erecta, Genista sagittalis, Arnica montana, Antennaria dioica, Nardus stricta, Cuscuta epithymum, Polygala vulgaris and rarely, Diphasium tristachyum. (5) A group of typical acidiphilic forest border species: Teucrium scorodonia, Melampyrum pratense, Centaurea nemoralis, Hieracium umbellatum, H. laevigatum, Lathyrus linifolius, Hypericum pulchrum. (6) A group of forest species: Deschampsia fiexuosa, Holcus mollis, Anemone nemorosa, Vaccinium myrtillus, Convallaria majalis, Carex pilulifera, Quercus petraea and robur, etc. The Daphno cneori-callunetum, which is integrated into the Genistion pilosae alliance, shows phytosociological affinities with other subcontinental thermophilic heathland groups such as Genisto pilosae- Callunetum avenetosumpratensis, described by Korneck (1974) of the Rheinhessen and Euphorbio-Callunetum avenetosum pratensis, studied by Schubert (1960) in the region near Halle in Germany and the Genisto germanicae-callunetum, established by Oberdorfer (1957, 1978) in the south of Germany. The Daphno-Callunetum consists of a mesohydric heath, developed on sandy soils, although relatively rich in fine elements (sum of clay and lime levels are between 10 and 25%). This heathland plant community enters into contact in the following ways. (a) n its superior margin with a xerophilic heath (integrated to the Genisto pilosae-callunetum), characterized by a much poorer floristic composition, the first group (thermophilic species) being only represented by Festuca guestfalic and Anthericum liliago. (b) n its inferior margin with a hygrophic heathland (attached to the Juncetum squarrosi sphagnetosum compacti), in which some moorland species (Juncus squarrosus, Eriophorum vaginatum, Vaccinium uliginosum, Gentiana pneumonanthe, Sphagnum compactum, S. molle, etc) appear. These three heathland types form a remarkable toposequence of continental heathlands, similar to those of atlantic areas (Muller, 1985a). All these heathlands consist of secondary milieux, created and upkept by human activities. Actually, they exist almost solely on the military terrain in Bitche, where they are affected by fires or the circulation of military tanks (Muller, 1988).

6 Post-glacial history of P vernalis and D. cneorum 133 Table 1. Synoptic table of the floristicomposition of mesohydric heath (1, Daphno-Collunetum), oak forest border (2, Antherico- Teucrietum) and oak forest (3, Luzolo-Quer-cetum) in Pays de Bitche, Vosges. Reference number of syntaxa Number of samples Continental or Submediterranean thermophilic species Anthericum liliago V V Festuca guestfalica V V V Avena pratensis Polygonatum odoratum Caoex montana Genista germanica Galium boreale Serratula tinctoria Peucedanum oreoselinum + Thymuseipyllum Daphne cneorum Pulsatilla vulgaris Pulsatilla vernalis va,: bidgostiana + Silene vulgaois + V Trifoliumedium Tr ifolium alpestre Campanula persicifolia Hypericum montanum Rubus saxatilis + Geranium sanguineum + 2. Semi-hygrophilic species Molinia caerulea V V Pteridium aquilinum V V V Frangula alnus V V V Stachys officinalis V V Succisa pratensis Gentiana pneumonanthe Dactylorhiza maculata Caoex panicea Genista tinctor-ia + 3. Oligotrophic grassland species Campanula rotundifolia V Hier acium pilosella V Euphorbia cypaoissias V Veronica officinalis V Luzula campestris Pimpinella saxifoaga Rumex acetosella Achillea millefolium Hypericum perforatum Festuca nigrescens Caoex caryophyllea + Agrostis vinealis V + Lotus corniculatus + Galium pumilum + continued

7 134 Serge Muller Table -continued. Synoptic table of the floristicomposition of mesohydric heath (1, Daphno-Callunetum), oak forest border (2, Antherico-Teucrietum) and oak forest (3, Luzolo-Quercetum) in Pays de Bitche, Vosges. Reference number of syntaxa Number of samples Hypochoeris r-adicata Festuca filifor-mis Jasione montana Veronico chamaedrys Thymus pulegioides 4. Heathland species Calluna vulgatis V Sarothamnuscopao-ius V V Potentilla er-ecta V Viola canina V Danthonia decumbens V Genista pilosa V Genista sagittalis Polygala vulga-is Arnica montana Antennaria dioica Nao-dustr-icta Cuscuta epithymum Diphasium tristachyum + 5. Acidiphilic forest border species Teucr-ium scorodonia V V V Hypericum pulchrum V V Melampyrum pratense + V Centaurea nemoralis Hieracium umbellatum V V Hieo-acium laevigatum Lathyrus linifolius Fragaria vesca V 6. Forest species Deschampsia flexuosa V V V Holcus mollis V Anemone nemor-osa V Convallaria majalis V Vaccinium myrtillus V V Agrostis capillaois V V Corex pilulifeo-a V V V Quercus petraea V Quercus robur Pinus sylvestris V V Fagus sylvatica V Caopinus betulus V Luzula pilosa Luzula luzuloides V Maianthemum bifolium Viola riviniana V Sorbus aucuparia V

8 Post-glacial history of P. vernalis and D. cneorum 135 DSCUSSON These heaths show clear floristic affinities with oak forest border vegetation in the area. This border vegetation group is classed in a particular association, the Antherico-Teucrietum, in the alliance of the Teucrion scorodoniae. The same species groups 1 to 6 are present with a high presence (see Table 1), but this association can be distinguished from Daphno-Callunetum on the floristic scale by the following: (a) the presence of border and forest species absent from the heaths in the area, such as Trifolium alpestre, T medium, Campanula persicifolia, Hypericum montanum, Silene vulgaris, Viola riviniana, Carpinus betulus, Fagus sylvatica, etc; (b) the rarity or absence of certain typical heath species (Genista pilosa, G. sagittalis, Calluna vulgaris, Arnica montana, Antennaria dioica, Nardus stricta); (c) the actual absence of Daphne cneorum, Pulsatilla vernalis and P vulgaris. Thus the numerouspecies of the Daphno-Callunetum could find their natural stations in the communities of the Antherico-Teucrietum. Furthermore, an important group of mesohydricthermophilic species from the Daphno-Callunetum and the Antherico-Teucrietum form the accompanying species of the sandy, thermo-acidiclinic association Peucedano-Pinetum in Central Europe, such as Peucedanum oreoselinum, Galium boreale, Polygonatum odoratum, Genista tinctoria, G. germanica, Serratula tinctoria, Convallaria majalis, etc. (Matuskiewitz, 1962). The edaphic characteristics of the Daphno-Callunetum and the Peucedano-Pinetum (brown acid or ochre soils with a sandy texture) are identical. These floristic and edaphic similarities lead one to believe that in Bitcherland these common species are relicts of the Boreal Period (around to BP) during which the Peucedano-Pinetum or a similar plant community could have represented the climatic climax of this territory. Daphne cneorum and Pulsatilla vernalis were equally, although more rarely mentioned in the Peucedano- Pinetum communities of continental areas. Thus, the most important populations of Daphne cneorum in Poland are found in a pine forest, accompanied by Peucedanum oreoselinum, Galium boreale, Polygonatum odoratum, Rubus saxatilis, Genista germanica, Convallaria majalis, Campanula persicifolia, Geranium sanguineum, Trifolium alpestre, etc, all species equally present in the Antherio-Teucrietum or Daphno- Callunetum of the Pays de Bitche (Glazek, 1969); 70% of the species mentioned by Glazek is this pine forest are present in the mesohydric heaths and oak forest borders in Bitcherland. Even Pulsatilla vernalis appears in such pine forests in Brandebourg, accompanied by Thymus serpyllum, Scorzonera humilis, Pulsatilla patens, etc (Libbert, 1932/33), in Estonie with Peucedanum oreoselinum, Campanula persicifolia, Arnica montana, Rubus saxatilis, Polygonatum odoratum, Convallaria majalis, Geranium sanguineum, Scorzonera humilis, Pulsatilla patens, etc (Steffen, 1931), as well as in vicarious communities of Scandanavian pine forests (Kielland-Lund, 1981). Also, Daphne cneorum and Pulsatilla vernalis are reunited in the Baviere pine community of the Peucedano-Pinetum (in the Regensburg region), and accompanied by Peucedanum oreoselinum, Genista germanica, G. tinctoria, Avena pratensis, Antennaria dioica, Thymus serpyllum, Scorzonera humilis, Pulsatilla patens, etc (Hohenester, 1960; Korneck, 1974). The actual presence of these two species in such continental European pine forests of Peucedano-Pinetum leads one to believe that these species could also have occupied pine woods of the Peucedano-Pinetum Bitcherlan during the Boreal Period. t is hypothesized that as the oaks replaced the mesophilic pinewoods during the Atlantic Period, Daphne cneorum and Pulsatilla vernalis were repressed to the forest edges and clearings, as were the other semiheliophilic species of the Peucedano-Pinetum which still are found in the heaths and oak forest borders of Bitcherland. Moreover, the global warming during this period led to the colonisation of these mesophilic stations by a group of subatlantic or submediterranean species (such as Teucrium scorodonia, Hypericum pulchrum, Lathyrus linifolius, Holcus mollis, Sarothamnus scoparius, Anthericum liliago) which entails the current floristic composition of the Antherico-Teucrietum and Luzulo-Quercetum associations. The Silvester pine has been maintained in the extreme stations on dry (Leucobryo-Pinetum) or peaty soils (Vaccinio uliginosi-pinetum), which were not compatible with the growth of oak woods (Muller, 1985b, 1992). But none of the mesohydric-thermophilic continental species group of the Peucedano-Pinetum mentioned above was kept up in these dry or peaty pine associations. The heaths were created in Bitcherland by the overexploitation of the forests during the Middle Ages (Noel, 1934). The Daphno-Callunetum association is

9 136 Serge Muller therefore a fairly recent plant community (less than 1000 years old), which replaced some oak forests of the Luzulo-Quercetum (Muller, 1988). ts composition came from the oak forest border flora, which explains the close floristic similarities of both milieux. Therefore, both associations contain a recent sub-atlantic group, formed by the species from the 'atlantic oak woods', and a continental group, consisting of ancient species from the pine woods in the Boreal Period. The development of an intensive forestry industry in the middle of the nineteenth century (the setting up of forestry practices and the massive replanting of open areas with the Silvester pine), almost caused the complete destruction in the state forests of the heath milieu and pushed the vegetation groups of the forest borders to parcel edges and forest paths. The most sensitive species, such as Daphne cneorum and Pulsatilla vernalis have therefore disappeared from these perturbed areas. The creation of a military terrain in Bitche in 1905 has fortunately allowed the conservation and even the restoration on this territory of vast heath assemblages of the Daphno-Callunetum, containing the remaining populations of Daphne cneorum and Pulsatilla vernalis. These two species therefore, do not form part of the current pinewoods in Bitcherland as ssler (1942) had presumed, but of the forest border and regressive heathland species of the oak forests of the Luzulo-Quercetum association. However, they representhe ancient species of a pinewood from the Boreal Period. CONCLUSON The phytosociological study of Daphne cneorum and Pulsatilla vernalis in Bitcherland has thus allowed the reconstruction of a hypothetical post-glacial evolution of their habitat in the territory. These two species, as well as other thermophilicontinental plants of that territory (e.g. Peucedanum oreoselinum, Galium boreale, Genista germanica, Polygonatum odoratum, Rubus saxatilis), constitute an ancient element of the Boreal Period, during which they occupied the mesophilic pine wood forests in the area. The post-glacial warming caused the replacement of these mesophilic pines by oak woods, provoking the repression of the semiheliophilic species of these pine woods to the borders of the oak forests, from where they then colonized the secondary heathlands due to their creation by overexploitation of the oak woods. Similar results, relative to such an ancient floristic element of the Boreal Period were obtained using the same phytosociological method by Carbiener (1963, 1969) and Bernard & Carbiener (1981). They established the existence in the sub-alpine thermophilic plant communities of the Calamagrostion of the Upper Vosges, of an ensemble of ancient continental species of the Boreal Period among which are Galium boreale, Rubus saxatilis, Serratula tinctoria, Dianthus superbus, Calamagrostis arundinacea. Also Rameau, in 1988, showed the presence in beech woods of the Cephalanthero-Fagion of Bourgogne, of a group of relict pinewood species from the Boreal Period, among which are found Daphne cneorum, Carduus defloratus and Buphthalmum salicifolium. These different studies show the importance of the continental relictual element of the Boreal Period in the flora of the sub-continental regions in Europe. They also illustrate the benefits that historical phytogeography can obtain from a phytosociological study of the current vegetation. REFERENCES Aymonin, G. (1958) Quelques aspects des phytocoenoses a Daphne cneorum, en particulier en Pays Basque frangais. Bull. Centre Et. Rech. Sci. Biarritz, 2, Aymonin, G. (1959) Essai d'une monographiecologique du Daphne cneorum. Rev. Gen. Bot. 66, Bernard, A. & Carbiener, R. (1981) Etude des 6cotypes d'especes collectives praticoles infeodees aux prairies subalpines primaires (Calamagrostion arundinaceae) des Hautes Vosges. Comparaisons aux taxons collin6ens et planitiaires correspondant de la r6gion Alsace. 2eme partie: les taxons a affinit6s continentales. Doc. phyt. NS, 5, Carbiener, R. (1963) Un remarquable groupement v6g6tal des hautes Vosges: la Calamagrostidaie subalpine. C R. Acad. Sc. Paris, 256, Carbiener, R. (1969) Subalpine Hochgrasprarien im herzynischen Gebirgsraum Europas, mit besonderer Berucksichtigung der Vogesen und des Massif Central. Mitt. Flor. -soz. Arbeitsgem., N.F. 14, Conard, H.S. (1954) Phylogeny and ontogeny in plant sociology. Vegetatio, 5-6, Edelman H.J. (1985) Late glacial and Holocene vegetation development of "la Goutte Loiselot" (Vosges, France). Dissertation, University of Utrecht. Glazek, T. (1969) Preliminary investigations the ecology of Daphne cneorum. Rocz. Dendr. 23, [in Polish, with English summary]. Guinochet, M. (1973) Phytosociologie, 227 pp. Masson, Paris. Hatt, J.P. (1937) Contribution a l'analyse pollinique des

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