Early Holocene land floras and faunas from Edgeoya, eastern Svalbard OLE BENNIKE and LARS HEDENAS Bennike, 0. & Hedenas, L. 1995: Early Holocene land floras and faunas from Edge~ya,eastern Svalbard. Polar Research 14(2), 205-214. Early Holocene, near-shore marine sediments from Visdalen, Edgeaya, eastern Svalbard contain locally abundant allochthonous remains of land plants, notably bryophytes. Wetland species indicative of mineral- rich and calcareous soils are frequent, but upland plants are also well represented. The fossil assemblages are indicative of ecological and climatic conditions similar to those on Edge~yatoday. The sediments contain one of the first fossil beetles reported from Svalbard. Apparently, the modern flora of Svalbard was already established in the earliest Holocene, probably following immigration from northern Europe. A few Armeria scabra remains are believed to be derived from interglacial deposits. Ole Bennike, Geological Survey of Denmark and Greenland. Thoravej 8, DK-2400 Copenhagen NV, Denmark; Lars Hedenas, Department of Crvptogamic Botany, Swedish Museum of Natural History, Box 50007, $104 05 Stockholm, Sweden. Europe demonstrate the mobility of plants (Birks Introduction 1994). Apart from exotic driftwood, pre-Holocene, Palaeoecological studies of Early Holocene Quaternary plant remains are rare in Svalbard terrestrial/limnic sediments have been carried out (Ingolfsson et al. 1995); however, a number of by Hyvarinen (1968, 1970, 1972). Surova et al. Holocene lake and peat deposits have been inves- (1982), Gottlich & Hornburg (1982), van der tigated, mostly by means of pollen analyses. Only Knaap (1989), Birks (1991) and Wohlfahrt et al. a few of these go back to the Early Holocene, (1995). In addition, there is a find of Polytrichum and very little is known about the immigration coinrnune Hedw. dated at 9870 * 140 years BP history of Svalbard flora and fauna. An exception (Salvigsen & Mangerud 1991). Surova et al. is the dyarf birch Betula nana that seems to have (1982) obtained a 14C date of 10,360 * 260 years immigrated to central Spitsbergen around 6000 BP (Tln-270) on basal peat from Reindalen on I4C years BP (Surova et al. 1982). Nathorst (1883) central Spitsbergen. They presented a rather was of the opinion that a few hardy species poss- crude pollen diagram from the peat section with ibly survived the last glacial stage on Svalbard. only few pollen and spore types from indigenous but that by far the majority of the vascular plants plants. The oldest peat date appears to come from immigrated after the last ice age via a land bridge Agardhdalen, western Spitsbergen, from where joining Svalbard and Scandinavia. Other scien- Punning et al. (1978) reported a date of tists, however, find support for the refugium 10.570 * 360 years BP (Tln-232). Van der Knaap hypothesis (R~nning1965; Odasz 1991; Odasz et (1989) obtained a I4C date of 6710 5 80 years BP al. 1991). One argument is that the plants could on basal peat from a section in Rosenbergdalen, not immigrate to Svalbard after the last ice age northwestern Edgeoya. Both macrofossil and pol- because no land bridge connected the archipelago len diagrams were published from the site. Only with the European mainland. However, the fact macrofossils of Salk polaris, Gramineae and five that the small. isolated, volcanic island Jan moss taxa were found in the section, but to this Mayen, which has never been connected to any must be added 25 pollen and spore types. Van continent by a land bridge, has been populated der Knaap concluded that the deposit and flora by 62 species of vascular plants (Lid 1964) shows of the former mire indicated that the climate was that long distance dispersal of plants does take warmer than today during peat accumulation. place across oceans in the Arctic. Many studies of Palaeoecological studies of lake deposits from full and late-glacial phytogeography in northwest Svalbard are even fewer than those of peat 206 Ole Bennike & Lars Hedenas deposits. Hyvarinen (1968. 1970. 1972) studied and animals that throw light on the history of lake sediments on northern Svalbard and Bj~rn- Svalbard flora and fauna. The remains come from Bya by means of pollen analysis. One of the sediment samples from Visdalen on the north- sequences from northern Svalbard dated back to western part of the island of Edgeoya, eastern ca 1Oka. but the interpretation of the pollen Svalbard (Fig. 1). A preliminary report on the diagrams is difficult due to a high content of present material that included some tentative long distance transported pollen. Birks (1991) moss identifications was published by Bennike presented a detailed macrofossil diagram from ( 1992). lake sediments from Skardtj~rna,western Spits- bergen. The basal sediments were dated by accel- erator mass spectrometry (AMS) on Salk and Study area Saxifraga remains to 8 ka. There is no safe indi- Edgeoya covers 5 150 km2 and is the largest island cation in Birks' study that any plants arrived after in the southeastern part of the Svalbard archi- this date. whereas three taxa were found that do pelago; extensive areas are glaciated, although not presently grow in the area. and a mean July the island is relatively low (Norderhaug 1970). temperature about 2°C higher than today was The bedrock is dominated by Triassic sandstone inferred for the Early Holocene. Wohlfahrt et al. and mudstone with layers of limestones and thin (1995) suggested that the mean July temperature coal seams in places, intruded by some dolerite on Bjsrnoya may have been as much as 45°C sills (Lock et al. 1978). The northwestern part of higher than present in the Early Holocene, based the island suppoits the richest vegetation and on beetle data. Terrestrial plant macrofossils in belongs to the Salix polaris zone of Brattbakk near-shore marine sediments from Adventfjor- (1986). Large areas are virtually barren, but the den, wchtern Spitsbergen. were studied by Heer dwarf shrub Salixpolaris is common in favourable (1870) and Anderson (1910). They found abun- sites. Ninety-three species of vascular plants are dant fruit stones of Empetrum tiigritm that no known from the island (Neilson 1970). From the Longer fruits in this area. flora and vegetation a mean temperature for the The aim of this paper is to describe and inter- warmest month of around 2°C is suggested for the pret some remains of terrestrial and limnic plants northwestern part of the island. big. 1. Left. Map of Sralbard. The arrow shows the location of Visdalen on Edgeoya. Right: Map of Visdalen ahowing thc location of the studied aampleb Contour interval 20 rn; contours only showed in Visdalen. For detailed description of the sites. see Moller er al. (19Y5) Early Holocene land floras and faunas from EdgeGya, eastern Soalbard 207 Turcz. We use the name A. scabra which is the Material and methods one currently in use in Greenlandic botany Seven samples were collected during the PONAM (Bocher et al. 1978). It is possible that some of 1991 expedition to eastern Svalbard. For the seeds referred to Draba sp. represent other descriptions and interpretations of the sampled Brassicaceae genera. All Salk remains (leaves, sediments, see Moller et al. (1992, 1995). The bud scales, fruit capsules, bark and wood) are sediment samples consisted of fine sand and silt referred to Salix polaris, to which the diagnostic with allochthonous plant and animal remains, leaves belonged, and which is the only willow some of which were well preserved, indicating species presently growing on Edgeoya. Tar- short transport. The samples were wet-sieved axacum achenes were similar to Taraxacum bra- through 0.42 and 0.21 mm sieves, and the residue chyceras achenes which have smaller spines than left on the sieves was sorted under a dissecting T. arcticum (Trautv.) Dahlst. achenes, the only microscope. other Taraxacum species on Edge~yatoday; but Most of the bryophyte remains were well pre- if the achenes are interglacial in age the species served, which made it possible to identify a large identification becomes uncertain. proportion of the material to a taxonomic level Lepidurus was represented only by apodous where a partial reconstruction of the paleo- segments. For climatic reasons the remains are environment becomes possible. The bryophyte referred to Lepidurus arcticus. Olophrum was material is deposited in the Department of Cryp- represented by one elytron and possibly a tergite. togamic Botany, Swedish Museum of Natural His- The elytron can not be identified at the species tory (No. 520644-620650). The other material is level, but since 0. boreale is the only species housed in the Geological Museum, Copenhagen. recorded from Svalbard at present (Fjellberg The bryophyte nomenclature follows Corley et 1983), the fossil elytron has been referred to this al. (1981), with additions in Corley & Crundwell species (J. Bocher, pers. comm. 1992). (1991) except for Brachytheciurn coruscum I. Wag. (B. groenlandicq), Polytrichastrum alp- inum (Hedw.) G. L. Sm. (Polytrichum alpinum). P. sexangulare (Brid.) G. L. Sm. (Popytrichum Results and discussion sexangulare), Pseudocalliergon angustifoliurn Non - bryophytes Hedenas (Hedenas 1992b), P. trifarium (Web. & Mohr) Loeske (Calliergon trifarium), P. tur- Identified land and freshwater plants and animals gescens (T. Jens.) Loeske (Scorpidium turges- are listed in Tables 1 and 2 and some remains cens), Scorpidium cossoni (Schimp.) Hedenas are illustrated in Fig. 2. The samples were small (Drepanocladus cossoni) . Straminergon stram- (Table l), but nevertheless some of the assem- ineum (Brid.) Hedenas (Cal[iergon slramineum) blages are diverse. Samples 87711. 87728 and and Warnstofia sarmentosa (Wahlenb.) Hedenas) 86251 contained marine fossils, showing that these (Calliergon sarmentosum). Tracheophyte assemblages were deposited in shallow water mar- nomenclature follows Ronning (1979). ine environments, probably near the mouth of a river. The marine fossils comprise the following animal groups: foraminifera, hydroids, serpulids. ostracodes, barnacles, malacostracans, molluscs, Identification echinoids, bryozoans and fishes and the brown Seeds of Melandrium apetalum were identified algae Sphacelaria sp.