Preistoria Alpina
Initial considerations on the Wiirmian Tardiglacial malacological records at Dalmeri rockshelter (Grigno-Trento)
ALBERTO GIROD
ABSTRACT - The structure of the mollusc fauna of the Wiirmian Tardiglacial AllerOd coming from the Early Epigravettian stratigraphy, shows different occurrence of specimens per m2, both during the periods of light or strong anthropization or inside the excavated area. These differences might be connected with human disturbance in the rockshelter. The land snails have been studied according their biogeography and some biological and ecological aspects. We can observe several colonizations during successive and short phases. The Mollusc assemblages suggest a woodland environment with a constant presence of broadleaf trees and Keyconif woers,rds which: sometimes alternatively prevail. A period of aridity is present in Lev.14-14a. Parole chiave: Riparo Dalmeri; WiirmianTard iglacial; Mollusc assemblages; Colonisations; Palaeoenvironment Riparo Dalmeri; Tardiglaciale wiirmiano; Malacofauna; Colonizzazioni; Paleoambiente Alberta Girod -
Laboratorio di Malacologia Applicata, Via Savona 94/A, 1-20144 Milano
The malacological findingswere collected during considered. As for the different frequency within the excavations carried out in 1991-1993 and regard the excavation grids (spatial distribution), we can observe stratigraphic sequence known at that period, between that the areas near the rock wall (# 0) contained the Lev.3 and Lev. 18 (370cm depth). To be more precise, highest density of Mollusca, amounting to 33 specimens they refer to the final phase of the Wurm period, per square metre, while the areas further away from interstadial of Allerod, dated Early Epigravettian the rock wall between 2.5 and 3.0m (# L) show a lower Culture. General details regarding the orogeographic density, with 1.16 specimens per square metre. The site position, the aspects of the anthropic settlement of next to the rock wall is rich of accumulated and well Dalmeri rockshelter as well as information on the preserved mollusc fauna. 24 species were identified and surrounding area, are dealt with in other published 755 specimen were found in all: works (DALMERI & LANZINGER, 1991,1992; BASSEITI & DALMERI, 1995; CAssou et al., 1995). In particular, it 1. Cochlostoma henricae (Strobel) should be noted that the levels mentioned refer to the 2. Abida secale (Draparnaud) stratigraphy in the DALMERI& LANZINGERworks (1991). 3. Discus ruderatus (Ferussac) The frequency of Mollusca in the stratigraphy (Fig.1) 4. Discus rotundatus (Muller) is sporadic in the older levels; it is still low between 5. Aegopis gemonensis (Ferussac) Lev.14, 14a and 13 which show strong anthropization. 6. Aegopinella cfr. minor (Stabile) There is a significant increase of species and specimens 7. Oxychilus cfr. draparnaudi (Beck) in Lev.12 and 11-12 where anthropization is lower. 8. Euconulus fulvus (Muller) These are only general indications and are as yet 9. Cochlodina laminata (Montagu) incomplete in comparison to other cases that are well 10. Charpentiera itala (G.v. Martens) documented (GIRoD, 1997) due to the fact that between 11. Charpentiera stenzii (Rossmassler) Lev.ll and 3, the presence of Mollusca is not very 12. Macrogastra lineolata (Held) frequent even though anthropization is weak or 13. Macrogastra plicatula (Draparnaud) completely missing. Other factors such as the 14. Macrogastra asphaltina (Rossmassler) characteristics and the accumulation time of earth and 15. Clausilia parvula Ferussac rock materials in the stratigraphy must also be 16. Clausilia dubia Draparnaud 164
17. Clausilia cruciata Studer gemonensis and Helicigona illyrica confirms a last 18. Clausilia pumila Pfeiffer phase of colonization. 19. Neostyriaca corynodes (Held) In mollusc habitat, the stony-soils and the stony/ 20. Trichia cfr. leucozona (Pfeiffer) broken-up soils species are present and confmn the rocky 21. Helicodonta obvoluta (Muller) and crumbly nature of the substrata. The strictly open - 22. Helicigona illyrica (Stabile) country species are not found in the stratigraphy; hypo 23. Helicigona cingulata (Studer) thetical influences and connections with the Marcesina 24. Causa holosericum(Studer) grassland plains overlooking the Dalmeri rockshelter 1992) can be therefore be excluded. A strip (MARTEILO, These species were studied in various ways: of more or less dense woodlands between Marcesina and biogeography, ecological aspects, calcium-dependence, the Dalmeri rockshelter area probably acted as a barrier biological form, faunal association (Tab.1). It is often to the open-country mollusca. possible to confirm the opinions expressed by We can also note that in the mollusc assemblage compairing the data obtained. structure, the woodland association is predominant with A temporary colonization of Lev .17 regards the exception of Lev. lO, 6 and 5 where the stony-soils Discus ruderatus, followed by further phase of col species are more abundant. In particular, various onization in Lev .16 and 15 of species including the woodland species are not found in these levels: Discus "mountain" Clausilia dubia and Clausilia cruciata. rotundatus, Oxychilus cf. draparnaudi, Cochlodina A tundra woodland environment can be hypothesized laminata, Trichia cf. leucozona. It would seem that with a Betula, Rhodoreto- Va ccinetum and Mugeto here the woodlands thinned out leaving more open Rhodoretum habitat and with a very cold climate. spaces and glades. Species that live in a woodland environment such as A more thorough analysis of the woodland Cochlodina laminata, Charpentieria itala, Charpen complex, based on the presence of species connected tieria stenzii, Macrogastra lineolata, Helicodonta to plants with deciduous leaves and to leaf-litter areas, obvoluta are also present. This means that around evidenciated that this type of vegetation prevailed from 11260±100 BP the mollusc fauna included many el Lev. 15 to 10. From Lev. 9 to 5 there is an abundance ements and that the chorologic categories, including of Causa holosericum sometimes together with Discus Holarctic, European, Central European, Central ruderatus, more associated with conifer wood. Eastern European, Central-Southern European, Simultaneously, certain species of broadleaf tree Alpine-Apennine and Eastern Alpine species, assemblage are less abundant or disappear: confirms the central position of the Sette Comuni Charpentieria itala, Macrogastra lineolata, Plateau in the Prealpine Italian complex. This area Macrogastra plicatula, Clausilia cruciata. Therefore was an ideal habitat for species already present in the evaluation resulting from increment of C. holoseri the surrounding regions after the Wtirm Ill (FoRCART, cum is confirmed by the decline of species living in the 1966). A third phase of colonization follows in broad-leaf trees environment. Lev.14 and 14a with Cochlostoma henricae, Abida The analysis of the faunal associations always secale, Macrogastra asphaltina, Clausilia parvula, lead to mixed woodland environments with deciduous Neostyriaca corynodes, Helicigona cingulata; as broadleaf trees (or shrubs with deciduous leaves) and well as Discus rotundatus and Oxychilus cfr. conifers (Fig.2), with alternate phase in which one or draparnaudi,Europ eo-Mediterranean species and the the other prevail and other periods in which the Alpine-Carpathian Causa holosericum. In Lev. 12 woodlands probably thinned out. and 11-12 Aegopinella cfr. minor, Euconulus fu lvus, A relatively dry period of the environment in Clausilia pumila, Trichia cfr. leucozona can be Lev .14 and 14a is underlined by the brief presence added to these totalling 21 species that are of thermophile species: Cochlostoma henricae and simultaneously present. The environment appears to Abida secale and by the simultaneous appearance have evolved considerably and presents a variety of of Discus rotundatus and Oxychilus cf. microniches and microenvironments ideal for many draparnaudi in the Dalmeri rockshelter. The two species. This ideal situation was not founded in the last species probably found there ideal environment higher stratigraphic levels (from Lev. 11 to 3) even inside the more humid cavity (Grusn & MANTOVANI, though in Lev.9- 10 and 9 the presence of Aegopis 1979). 165
Discus ruderatus, SUMMARY - The malacological records concern the Early Epigravettian stratigraphy (Wtirmian Tardiglacial, AllerOd) of Dalmeri rockshelter, situatedClausilia on the Asiagodubia PlateauClausilia (Trento). cruciata We ,observe a quickChar colonizationpentieria byitala, Charpentieria stenzii,shade lovingCochlodina species laminata of easy, Maadventitioucrogastras andlineolata element ofHe Alpinelicodonta environments, obvoluta. first appearing in the oldest layers. A second stage of recolonization includes and togetherOxychilus with draparnaudi, Macrogastra asphaltina, Neostyriaca corynodes, Clausilia parvula, Helicigonaand cingulata, CausaThis holosericum. contingent of deciduous-broadleaf woodland asCochlostomasemblage was henricae followed byAbida a third secale quick arrival of other species: cf. In Lev. 14-14a the presence of and indicates a partial aridity. At 11260±100 BP the biotope seems well evolved, rich in rnicroniches and a variety of rnicroenvironments allowing the presence of many land snails. It is a woodland environment, including broadleaf and conifer trees and showing some transitory changes: the broadleaf trees prevail from Lev.15 to Lev.lO and in Lev.3. The presence of conifers is more important from Lev.9 to Lev.S. The anthropization of the rockshelter might be a cause of disturbance for the Mollusca, both in time and in different points of the excavated area. Those nearer the rockwall supplied more abundant records.
RIASSUNTO - Si studia la struttura della malacofauna del Tardiglaciale wtirrnianodi AllerOd proveniente dalla stratigrafia epigravettiana. Sono state evidenziate diverse densita di individui al m2 sia nella stratigrafia che tra differenti punti del l' area di scavo; differenze temporali e spaziali in parte attribuibili al disturbo antropico. I Molluschi terrestri vengono esarninati sotto gli aspetti della geonernia e delle categorie corologiche, valenza ecologica, calcio dipendenza, forma biolo e gica. Si notano fasi successive di colonizzazione del Riparo Dalmeri e con l'analisi delle associazioni faunistiche si indivi dua un ambiente ove sempre presente un bosco rnistocon piante a foglie decidue e con conifere; si hanno fasi alteme in cui prevale un tipo o l'altro di vegetazione. Vi e evidenza di un periodo di relativa aridita nei Liv.14-14a.
REFERENCES
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BASsEITIM. DALMERI G., 1995 - Riparo Dalmeri e GrottaActa L., 1966 - Die Schneckenfauna der Isteiner Klotzes d'GeologicaEmesto: antichi insediamenti umani della Marcesina in Wandel der Zeiten. In: Der Isteiner Klotz, zur ASsousull' Altopiano dei Sette Com& TAGLIAcozzouni (Trento). Naturgeschichte einer Landschaft am Oberrhein, p.369- 70: 125-134 408. Ed. Rombach Freiburg im Breisgau C P.F., DALMERI G., FroRE I. A., 1995 GIRoD A., 1997 - Arene Candide: Holocene land-snails. (in stampa) - Abri Dalmeri (Trento, ltalie): la chasse In: Maggi R. (ed), Arene Candide: a FunctionalMem. Ist. ita!.and dans un gisement epigravettien de montagne. In: 5th Peleont.Environmental umana Asses sment of the Holocene Sequences VISPP Int. Congress, 12th Commission, Epipaleolithic (Excavation& Bemabo Brea 1940- 1950). DALMERIand Mesoli thic& inANZINGER Europe, Grenoble (Isere - France), 5: 125-135 18-23 September 1995 Grusn F. MANTOvANI E., 1979 - Le malacofaune conti (VR). Boil. Mus. civ. St. nat. Ve rona G.Preistoria L alpina M., 1991 - Ricerche nentali quatemarie del Riparo Tagliente in Valpantena MARTEU.D paletnologiche& LANZINGER e paleo ambientali al Riparo Dalmeri 6:19-72 (Trento). 25:223-229 G.V., 1992 - Cicli climatici e storia della vege DALMERI G. M., 1992 - Abri Dalmeri. In: tazione nella Piana di Marcesina. In: P.Favero (ed), La Colloque international, "Adaptation au Milieu Montagna di Enego e la Marcesina, p. 101-107. Cornu Montagnard au Paleolithique Superieur et au ne di Enego Mesolitique", p. 89-91 166
...I 11.1 ...I z z cc .u cc U l- :::!E Z ..... 2 0 -u :»11.1 '"'11.1 - !:a :::E cc� iii c '"' c:: SPECIES :1 Oo. U Z- Llo. ....I U) ....1z 11.1 o o :IU Llo. CCo,. ccoLlo.U) silo. Ul 2i gee11.1 u��.� Q ii5 cc
Cochm.tomehenrtcee Al E B c K RP
Abide •.c•le Eu B c K LB PE
9 D/sCU$ruderetus 01 M I K FC
9-10 0/eCU$rotund•tus Eu M B I K FL
10 A� Al E B I K FPE
11 Aegoplnel/ecfr. minor Eu CS B I H LB PE 11-12 1 Ox/chy/IJ$ cfr. dntpemeudl Eu M B I H FPE 12 Euconulua fu/vus 01 B I H FL 13 Cochlodine leminet. Eu B I K F
148 Che/f1Mifierie itel• AI Ap B c K FL RP
14 Che,.,.mierie stenzii Al E B c K RP
15 M•�etre lineolete Eu C M I K FL PE
16 M•crog,.tr.•tul• pllc Eu CE B I K FL
17 Me�str. nphe Hin• Al E B I K FL RP 18 C/eusiHe pervule Eu CE B c K PE
10 20 30 50 60 70 C/eu.ille dubiil Eu CE B c K PE
C/euailie cruciete Eu B M I K FL PE
m2frequency C/euailiepumi/ e Eu E B I K FL
Neoetyrle ce coqnodn AI M c K PE Fig. 1 - Frequency of Mollusca in the stratigraphy Trichie cfr. leucozone Al E B I K PE .... H.ucodont• obvolut• Eu CS B I K FL
HeliciQOIIeil /yrlc e AI E Di B I K PE
Helicigone•t• clfiJJIII AI � B c CM RP
. 7 Ceuu holouricum Al Ga M I K FC
- L. Tab. 1 systematic list and information regarding bioge 0-10 ography, ecological aspects, calcium-dependence,
10 biological form and faunal association of every species: Diffusion: Al) Alpine; AlAp) Alpine-Apennine; AlCa) Al , ..... pine-Carpathian ; AlE) East Alpine; AlEDi) Alpine 1 11-12 Eastern-Dinaric; Eu) European; EuB) Euroboreoalpine; EuC) Central European; EuCE)01) Central-East European; 12 .... EuCS) Central-South European; EuE) Eastern European; 13 EuM) Euromediterranean; Holarctic