Riparo Mochi is considered a key site for the Middle–Upper Palaeolithic chrono-cultural sequence in the Mediterranean area. Climatic and environmental conditions have been reconstructed after the study of the small mammal assemblage by means of linear regression method and the Habitat Weighting method. The climate proxies for the late Mousterian and Proto-Aurignacian (cultural units I to G) indicate an environment with a relative high percentage of forest component during two cold and one relative warm oscillations. Open environments with low temperatures are registered for the Gravettian (cultural Unit D) allowing a possible relation to the Heinrich 3 Event. The final Gravettian (cultural Unit C) shows a relative warm peak, tentatively related to Greenland Interstadial 2. The late Epigravettian (cultural Unit A) is characterized by a high percentage of forest-related environment suggesting that this horizon formed during the Bølling–Allerød Interstadial. Finally, the Riparo Mochi sequence contributes to reconstruct the processes of faunal changes along the northern Tyrrhenian coast in a period of climatic instability, especially during the end of Marine Isotope Stage 3 when foraging groups adopted different mobility strategies between southern France and the Italian peninsula.
Le Riparo Mochi est un site clé pour la séquence chrono-culturelle Paléolithique moyen–supérieur de la région méditerranéenne. Les conditions climatiques et environnementales ont été reconstruites à partir de l’étude de l’assemblage de petits mammifères par les méthodes de moyennes de régression linéaire et
The environment and climate reconstructions of MIS 3 and 2 of central and southern Europe have been widely discussed (
Thirteen continuous and repeated climate cycles, such as Dansgaard–Oeschger (DO = GI) and Heinrich Events (H), have been recognized between 50,000 and 20,000 years BP in Greenland and North Atlantic cores (
In this context, little is known about small mammal variations in northwestern Italy during MIS 3 and 2, especially in the coastal region (
Here, we present for the first time a study of the entire collection of small mammals (insectivores and rodents) from the Riparo Mochi site (Balzi Rossi, Ventimiglia, Italy). This site holds one of the most important sections in the Tyrrhenian area, spanning from Mousterian to Epigravettian, and it is considered a key site for the investigations on the Middle-Upper Palaeolithic boundary (
Riparo Mochi (Mochi rock shelter) is a broad, shallow rock shelter situated in the Balzi Rossi archaeological complex, in western Liguria on the border between Italy and France (43°47′3.66″N, 7°32′4.18″E, 30 m a.s.l.). It is one of several prehistoric sites, also known as “Grimaldi caves” (
The site was discovered in 1938 by A.C. Blanc and L. Cardini of the Italian Institute of Human Palaeontology (IsIPU). They performed first a small-scale testing over three trenches (A, B, C) (
The chronocultural sequence, approximately 10 m deep, consists of nine units, mainly inferred in retrospect upon the characteristics of the embedded cultural remains (
Several paleoenvironment analyses have been previously carried out on Riparo Mochi. These studies have focused on the pollen sequence (
Twelve pollen samples collected from cultural Units G and F–E (1959 Cardini sequence, East sector) allowed us to reconstruct the environment of the region at the beginning of the Upper Palaeolithic (
The faunal evidence coming from Riparo Mochi was only partially studied by several authors.
A more detailed study of the large mammals evidence coming from Unit D (Gravettian, 1959 Cardini's excavation) is presented in
A sample of small mammal fauna, collected by the “Laboratoire départemental de Préhistoire du Lazaret” in 1993 (
The small mammal remains from Riparo Mochi are represented by disarticulated bone fragments collected by water-screening using 1 mm mesh sieves during the Cardini (1938–1949, 1959) and Bietti (1995–2005) campaigns. The small mammal assemblage includes a total of 1244 remains, corresponding to a minimum number of 795 individuals (
The taxonomic classification follows
We calculated the palaeodiversity using the Simpson index of Evenness = 1–∑(
In order to reconstruct the paleoenvironment at Riparo Mochi, we used the Habitat Weighting method (
Paleoclimatic data from Riparo Mochi have been calculated using the bioclimatic model described by
Afterwards, the Bioclimatic Component (BC) was calculated using the following formula: BC
The small mammal assemblage of Riparo Mochi is characterized by high percentage of open environment-related arvicolids such as
The BC
As the Units from I to E (
In Unit I (NMI = 45), the biodiversity is high and equally distributed (Simpson index = 0.865;
The cold climate evolves to slightly warmer conditions through the sequence (Units H and G) reflected in a more open environment. The rise in temperature and open environment may be related to a different precipitation distribution that caused the loss of biodiversity and the forest environment reduction (
Unit F (early Aurignacian) is the most reliable layer of this portion of the sequence (NMI = 75): it is dominated by
The loss of equality in the small mammal assemblage distribution continues in Unit E of Riparo Mochi. Here, few small mammals have been recovered (NMI = 23) to reach the lowest values in Unit D. Phases D IV, III, and II are dominated by one species,
After the thin and sterile Unit B, the Riparo Mochi sequence ends with the cultural Unit A (Epigravettian). This Unit also has a low NMI but the high percentage of forest-related indicators and the relative warm temperatures suggest that the unit formed in an environment similar to the present one.
The relatively high percentage of forest related species in Units I to F suggests that, in the period of time between DO (=GI) 12 and H 4 (following
Riparo Mochi Units from I to F can be compared to layers SU A5 + A6 to A1 of the Fumane Cave (Verona, Italy). There, a decrease in percentage of woodland coverage is registered and this reduction culminates in layers A3-A1 that are attributed to Heinrich Event 4 (
Three short and not yet chronologically determined interstadials characterized by sparse tree cover are also found in two French site pollen records: Les Échets, zone G (
The Unit D (phase III) temperature increase followed by an open environment decrease visible at the top of Unit D of Riparo Mochi can be related to episodes following the H3. No abrupt changes are visible in the transition from the top of Unit D to Unit C, although the latter is attributed to the final Gravettian technocomplex, chronologically related to Last Glacial Maximum (LGM) and DO 2 (
Italian small mammal sequences related to H3 and following DO cycles are very scarce; the climatic deterioration related to this event in northern Italy is visible only at Grotta del Broion (layers G2–F), where a decrease of forest related species is registered (
The late Epigravettian Unit A of Riparo Mochi is characterized by the high percentage of forest related species. The Unit probably accumulated after the turnover registered during the Late Glacial in the small mammal communities. In southwestern France, cold-climate species such as
The small mammal analysis from Riparo Mochi allows us to reconstruct the environment and its changes in the region surrounding the site from the final Middle Palaeolithic to the Upper Palaeolithic. The changes are due to D/O cycles and Heinrich Events registered during MIS 3 and 2 and detected in numerous climate proxies of European continental sequences.
Due to its particular position, the small mammal community of Riparo Mochi has been influenced by the Mediterranean climate and, even during the coldest stadial period of MIS 3, species related to boreal regions usually documented in northern Italy did not reach this area.
During the Middle to Upper Palaeolithic transition, two cold and one slightly warm oscillations were detected depicting a forest and bush reduction near the shelter. It was probably due to stadial moments not highlighted throughout the low small mammals MNI registered in the collection.
During the Gravettian, the environment changed from one dominated mainly by open grasslands, related to a cold and dry climate, to one characterized by open forests with an increase of water streams, the latter probably due to the flow rate of the near San Luigi river. The radiometric date at the base of Unit D and the presence of lithic tools related to final Gravettian in Unit C indicate that this portion of the sequence formed between H3 and D/O (GI) 2.
The small mammal assemblage of the uppermost Unit A, related to final Epigravettian, indicates the presence of a forested environment. This Unit probably formed after the faunal turnover registered in southern Europe during the Late Glacial.
The sequence of small mammal assemblages at Riparo Mochi fills a gap between southern Italy and southern France small mammal sequences, confirming the sequence as a reference one not only for the Middle to Upper Palaeolithic transition but also for the transition from MIS 3 and MIS 2.
The Dipartimento di Lettere e Filosofia, Università degli studi di Trento (Italia) partially supported this study. The former Soprintendenza per i Beni Archeologici della Liguria granted the permission for the study; in particular, we thank Dr. Angiolo Del Lucchese and Dr. Elisabetta Starnini. We are grateful to many people and friends who helped us during the fieldwork, especially to M. A. Segré and the staff of the Museo Preistorico dei Balzi Rossi. We want to thank the editorial secretary Fathia Lemhemdi and the reviewers Juan Manuel López-García and Lars van den Hoek Ostende for their comments that improved the final version of the manuscript. The authors also thank Benedetto Sala and Elisa Luzi for their useful suggestions and Julie Arnaud for the French spelling check. Finally, we are in debt with A. Segre who generously gave us direct information and original field documentation about the Riparo Mochi excavation.
BC
BC
A: Location of Riparo Mochi (red square); location of the most complete Italian Peninsula small mammal sequences (black squares); location of cited pollen records (blue dots). B: Riparo Mochi stratigraphy and selected radiocarbon dates cal BP (original drawing from Segre and modified from
Localisation du Riparo Mochi (carré rouge) ; localisation des séquences de petits mammifères les plus complètes de la péninsule Italienne (carrés noirs) ; localisation des données palynologiques citées (points bleus). B : Stratigraphie du Riparo Mochi (dessin original de Segre modifié par
Some identified small mammals from Riparo Mochi, all scales are 1 mm long. 1 and 2:
Exemples de petits mammifères identifiés au Riparo Mochi ; toutes les échelles sont de 1 mm de long. 1 et 2 :
Representation of the small mammal Simpson diversity index (1-D), the mean annual precipitation (MAP), the mean temperature of the coldest month (MTC), the mean annual temperature (MAT), the mean temperature of the warmest month (MTW) and the landscape percentages (OD: open meadows; OH: open humid meadows; W: woodlands; R: rocky areas; Wa: areas along streams, lakes and ponds). GI: Greenland Interstadial; GS: Greenland Stadial.
Représentation de l’indice de diversité de Simpson des petits mammifères (1-D), moyenne des précipitations annuelles (MAP), moyenne des températures du mois le plus froid (MTC), moyenne annuelle des températures (MAT), moyenne des températures du mois le plus chaud (MTW) et pourcentages de paysage (OD : prairies ouvertes ; OH : prairies humides ouvertes ; W : bois ; R : zones rocheuses ; Wa : zones le long de ruisseaux, lacs et étangs). GI : Interstade groenlandais. GS : Stade groenlandais.
Small mammal percentages of Minimum Number of Individuals (MNI) and small mammal distribution by habitat.
Pourcentages de nombre minimum d’individus (NMI) de petits mammifères et distribution des petits mammifères par habitat.
Biodiversity, Climate and Landscape values. Percentage representation of small mammal taxa associated with open dry meadows (OD), open humid meadows (OH), open woodland environments (OW), woodland environments (W), rocky environments (R) and landscapes constituted by river, lakes and ponds (Wa); bioclimatic components (BC
Valeurs de biodiversité, climat et paysage. Représentation des pourcentages des taxons de petits mammifères associés à une prairie sèche ouverte (OD), une prairie humide ouverte (OH), un environnement boisé ouvert (OW), un environnement boisé (W), un environnement rocheux (R) et des paysages constitués de rivières, lacs et étangs (Wa) ; composants bioclimatiques (BC