Morgane Ollivier
email: morgane.ollivier@univ-rennes.fr

Frédérique Barloy-Hubler

Sebastián Pérez-Díaz

Régis Debruyne

José Utge Buil

Françoise Dessarps

Dominique Marguerie

Philippe Lanos

José Antonio López-Sáez

Larbi Boudad

Jean-François Berger
email: jean-francois.berger@univ-lyon2.fr

Jose Utge-Buil

Unlocking the Past: Exploring Moroccan Lake Sediments through Ancient DNA and Palynology for Insights into Paleoenvironment, Land Use, and Practices

Keywords: Conceptualization, methodology, formal analysis, investigation, Writing- Conceptualization, resources, investigation, Writing-Original draft preparation pastoralism, Late Neolithic, Bronze Age, Morocco, Middle Atlas Lake, ancient sedimentary DNA, Palynology Highligths

Over the last 12,000 years, the adoption of an agro-pastoral lifestyle has become prevalent, leading to gradual change in landscapes. In northwestern Morocco, typical elements of an agropastoral economy emerged around 7,400 cal BP in the Tingitana Peninsula. This was associated with Cardial ceramic style and the presence of key cultivated plant species and domestic mammals. However, in this region, the archaeological record of the last five millennia remains fragmented, with significant regional variations that challenge our understanding of the neolithization processes. This study introduces a new five-meter-long core from Lake Iffer in the North African Middle Atlas. Our objective is to assess the site's potential to reveal insights into the impacts of climate and human activities on the ecosystems and the landscape of the Middle Atlas during the Holocene. Employing a pluridisciplinary approach, we combined paleolimnology and palynology with, for the first time in this context, ancient DNA analysis focusing on sedimentary samples spanning from Late Neolithic to Bronze Age.

Our findings reveal an environmental opening between 4.1-3.9 ka BP likely triggered by a drought episode, possibly associated with the so-called "4.2 ka cal. BP event". During the same period, we present evidence of increased anthropic pressure, reflected by the presence of ruderal taxa and Bovidae, despite the absence of archaeozoological material. It attests of pastoral activities at least 4,371 years ago at Iffer lake site while no evidence of cultivated plant taxa was found. Moreover, our study demonstrates that both climatic fluctuations and human activities contributed to the local decline of Elephantidae, as indicated by ancient sedimentary DNA Our findings offer new perspectives for exploring and studying Mediterranean sites with. limited material evidence.

Introduction

Over the past 12,000 years, human has seen his way of life change drastically. From nomadic he gradually became sedentary and the adoption of an agro-pastoral regime became widespread.

This transition was possible from the end of the Late glacial in Near East in parallel with climate changes [START_REF] Bar-Yosef | The origins of sedentism and farming communities in the Levant[END_REF], and spreads across the Mediterranean from the 9th millennium BP onwards [START_REF] Berger | The 8200calBP abrupt environmental change and the Neolithic transition: A Mediterranean perspective[END_REF][START_REF] Weninger | Climate forcing due to the 8200 cal yr BP event observed at Early Neolithic sites in the eastern Mediterranean[END_REF]. Intensification of the economy of production and increasing anthropization have gradually evolved over the last millennia, resulting in a gradual change in landscapes.

The Mediterranean region, situated between 30 and 40°N, is one of the most sensitive zones to climatic fluctuations which contributed to shape the ecosystems. Its geographical situation lies in a zone of influence of the North Atlantic oceanic circulation [START_REF] Brahim | North Atlantic Ice-Rafting, Ocean and Atmospheric Circulation During the Holocene: Insights From Western Mediterranean Speleothems[END_REF]. In the Mediterranean basin, past environmental changes have resulted from critical climate oscillations and growing ecosystem instability exacerbated by human activities over the past 9,000 years [START_REF] Cheddadi | Environmental changes in the moroccan western rif mountains over the last 9,000 years[END_REF][START_REF] Fletcher | Fragility of Western Mediterranean landscapes during Holocene Rapid Climate Changes. Long-Term Degrad[END_REF][START_REF] Mercuri | A marine/terrestrial integration for mid-late Holocene vegetation history and the development of the cultural landscape in the Po valley as a result of human impact and climate change[END_REF][START_REF] Sadori | The last 7 millennia of vegetation and climate changes at Lago di Pergusa (central Sicily, Italy)[END_REF].

In northwestern Morocco, typical elements of an agro-pastoral economy appeared in the Tingitana Peninsula around 7,400 cal BP [START_REF] Gibaja | Evidence of the use of threshing-boards in the spanish Meseta during the Copper Age. Microwear analysis of flint denticulates from 'the ditched enclosure' of El Casetón de la Era (Villalba de los Alcores, Valladolid)[END_REF][START_REF] Linstädter | Defining the Early Neolithic of the Eastern Rif, Morocco -Spatial distribution, chronological framework and impact of environmental changes[END_REF][START_REF] Marinval | Données palynologiques et carpologiques sur la domestication des plantes et l'agriculture dans le Néolithique ancien du Maroc septentrional (site de Kaf Taht El-Ghar)[END_REF][START_REF] Morales | The introduction of South-Western Asian domesticated plants in North-Western Africa: An archaeobotanical contribution from Neolithic Morocco[END_REF], Simoes et al. 2023), associated with Cardial ceramic style similar to that of the eastern coast of the Iberian Peninsula. This event is accompanied by the appearance of the main cultivated species of cereals and legumes, as well as domestic mammals common to the early Iberian Neolithic, [START_REF] Manen | Le Néolithique ancien de la Péninsule Ibérique: vers une nouvelle évaluation du mirage africain?[END_REF][START_REF] Martínez-Sánchez | The beginning of the Neolithic in northwestern Morocco[END_REF], suggesting that the Neolithic wave diffused from the southern coast of the Iberian Peninsula via sea crossing following a north to south axis [START_REF] Martínez-Sánchez | The beginning of the Neolithic in northwestern Morocco[END_REF].

However, the archaeological record of the last five millennia in northwestern Morocco remains very fragmented and poorly studied, with great regional contrasts that complicate the understanding of the chronology of the neolithization processes [START_REF] Lucarini | New Light on the Silent Millennia: Mediterranean Africa, ca. 4000-900 BC[END_REF][START_REF] Martínez-Sánchez | The beginning of the Neolithic in northwestern Morocco[END_REF]. Lake sediment changes and variations in sedimentation rate offer valuable information about past climate influences, water depth, and paleoenvironments [START_REF] Damnati | Sedimentology and geochemistry of lacustrine terraces of three Middle Atlas lakes: Paleohydrological changes for the last 2300 cal BP in Morocco (western Mediterranean region)[END_REF][START_REF] Magny | Holocene climate changes in the central Mediterranean as recorded by lake-level fluctuations at Lake Accesa (Tuscany, Italy)[END_REF]. These elements associated with the study of ancient remains and chrono-cultural frameworks helps understand biodiversity fluctuations and past land use impacts [START_REF] Cheddadi | A History of Human Impact on Moroccan Mountain Landscapes[END_REF][START_REF] Simonneau | Holocene land-use evolution and associated soil erosion in the French Prealps inferred from Lake Paladru sediments and archaeological evidences[END_REF]. Over the last two decades, lake sedimentary DNA has 3 This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d complemented pollen and macro-remains, proving valuable for studying past community-level changes [START_REF] Capo | Lake Sedimentary DNA Research on Past Terrestrial and Aquatic Biodiversity: Overview and Recommendations[END_REF]. It enables direct identification of organisms in sedimentary archives and helps understand changes in their representation over time. To date, such studies have never been performed in northwestern Maghreb contexts.

In Morocco, valuable information on ecosystem changes and species dynamics has primarily come from studies focused on the northern coasts, the Tingitane peninsula, and the Middle and High Atlas Mountains. Several multi-proxy studies of Middle Atlas lakes (such as Tigalmamine, Sidi Ali, Iffrah, Afourgagh) have documented the main hydroclimatic variations and the evolutionary trend of regional climate during the Holocene [START_REF] Lamb | Vegetational response to Holocene climatic change: pollen and palaeolimnological data from the Middle Atlas, Morocco[END_REF][START_REF] Rhoujjati | Environmental changes over the past c. 29,000 years in the Middle Atlas (Morocco): a record from Lake Ifrah[END_REF][START_REF] Zielhofer | Western Mediterranean hydro-climatic consequences of Holocene ice-rafted debris (Bond) events[END_REF]. Despite pioneering paleolimnological and pluridisciplinary works in the Middle Atlas lakes since the 1990s [START_REF] Cheddadi | Holocene climatic change in Morocco: a quantitative reconstruction from pollen data[END_REF][START_REF] Lamb | Vegetational response to Holocene climatic change: pollen and palaeolimnological data from the Middle Atlas, Morocco[END_REF], continuous and long Holocene records with robust absolute chronologies in Mediterranean North Africa remain incomplete, despite recent paleoenvironmental studies and anthropogenic impacts identification has been performed [START_REF] Cheddadi | Human demography changes in Morocco and environmental imprint during the Holocene[END_REF][START_REF] Cheddadi | A History of Human Impact on Moroccan Mountain Landscapes[END_REF][START_REF] López-Sáez | New challenges in archaeopalynology: Pollen analysis on Roman bivalve shells from south-western Europe and North Africa[END_REF][START_REF] Nourelbait | Climate change and ecosystems dynamics over the last 6000 years in the Middle Atlas, Morocco[END_REF]. Recently, a continuous study from Lake Sidi Ali archive reconstructs Western Mediterranean hydroclimatic variability, seasonality and forcing mechanisms. The study reveals low lake levels at 6.6-5.4 ka and from 3 ka, a multi-centennial-scale NAO-type pattern and Western Mediterranean, and a winter rain maximum generally associated with solar minima [START_REF] Zielhofer | Western Mediterranean hydro-climatic consequences of Holocene ice-rafted debris (Bond) events[END_REF][START_REF] Zielhofer | Atlantic forcing of Western Mediterranean winter rain minima during the last 12,000 years[END_REF].

Due to the scarcity of well-dated fossil records, the absence of reliable absolute chronologies, and incomplete archaeological studies in Mediterranean North Africa, a comprehensive analysis of spatial and temporal patterns of environmental variations and species dynamics, which could provide insights into land use and practices, remains challenging. In consequence, the process of progressive anthropization and the development of agro-pastoral practices which, in parallel with the climate, have shaped the environment in northwestern Morocco over the past 7,000 years, remain not fully understood. Therefore, these processes cannot be contextualized and integrated into the known patterns in southern Europe and the Near East edges of the Mediterranean.

In this study, we present a newly recovered five meters long core from Lake Iffer in the North African Middle Atlas. Our objective is to assess the site's capability in providing insights into the impacts of climate and human-induced changes on the Holocene ecosystems and landscape of the Middle Atlas. To achieve this, we employed a pluridisciplinary approach combining paleolimnology, palynology and, for the first time in this context, ancient sedimentary DNA 4 This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d (sedaDNA) analysis on a few samples to explore the potential of paleogenomic methods on such Mediterranean sites.

Study area

Lake Iffer (33°36'30''N, 4°54'30''W), located in northeastern Morocco (Figure 1A), is one of several lake systems in the tabular Middle Atlas Mountains at the boundary of the Imouzzère and Amekla causses [START_REF] Rhoujjati | Significations paléoenvironnementales des dépôts du remplissage holocène du lac Iffer (Moyen Atlas, Maroc)[END_REF]. Of moderate size (3.5 ha), it is located in a tectonokarstic zone of middle altitude [START_REF] Baali | Genèse et évolution au Plio-Quaternaire de deux bassins intramontagneux en domaine carbonaté méditerranéen. Les bassins versants des dayets Afourgagh et Agoulmam (Moyen Atlas, Maroc)[END_REF], and occupies the center of a watershed of endoreic type whose surface of 4.5 km 2 extends between 1500 to 1846 m of altitude (Figure 1B). The bein of the lake is composed of a calcic bicarbonate facies [START_REF] Benkaddour | Hydrologie et sédimentation actuelles au niveau des lacs Iffer et Aguelmam Azigza (Moyen Atlas, Maroc). Quat. Maroc. Actes 4e Rencontre Quat[END_REF][START_REF] Damnati | La sédimentation sub-actuelle dans le lac Iffer (Moyen Atlas, Maroc): Résultats préliminaires[END_REF], associated with the intense karstification of the liasic dolomites lying on an impermeable substratum formed by the Trias argillites [START_REF] Baali | Genèse et évolution au Plio-Quaternaire de deux bassins intramontagneux en domaine carbonaté méditerranéen. Les bassins versants des dayets Afourgagh et Agoulmam (Moyen Atlas, Maroc)[END_REF]. The lake is supplied by a network of gullies that function periodically during the rainy season, particularly well-marked on its eastern shore, connected to a vast lacustrine terrace. Its level fluctuates according to the seasons and the annual rainfall. The climate is Mediterranean sub-humid with cold winters.

Remnants of ancient red Mediterranean soils (terra rossa) are observed on the slopes, more or less heavily colluviated and brunified (rendziniform) by Holocene pedogenesis [START_REF] Alaoui | Application of Electrical Tomography to Put in Evidence the Thickness and Structure of the Filling of Dayet Iffer (Middle Atlas, Morocco)[END_REF]. The surrounding forest vegetation is composed of holm oaks (Quercus ilex) with a few feet of Aleppo and maritime pines (Pinus halepensis and P. maritimus). The matorrals are dominated by Thymeleae tartonraira and Adenocarpus [START_REF] Lecompte | Biogéographie de la montagne marocaine: le Moyen-Atlas central[END_REF]. The lake has significant water deficits because of recurring drought and human pastoral pressure since the 1980s, leading to the decrease in water level and increasing salinity, with relatively alkaline water [START_REF] Damnati | Sedimentology and geochemistry of lacustrine terraces of three Middle Atlas lakes: Paleohydrological changes for the last 2300 cal BP in Morocco (western Mediterranean region)[END_REF]. The aquatic flora of the lake is dominated by cattail (Typha latifolia), white water lily (Nymphaea alba), pondweed (Potamogeton pectinatus) and Eurasian watermilfoil (Myriophyllum spicatum), which are very dense near the shores [START_REF] Chillasse | Ecological values and functions of the wetlands of the Middle Atlas (Morocco)[END_REF].

5

This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d Morpho-stratigraphic analysis of the catchment was performed by [START_REF] Alaoui | Application of Electrical Tomography to Put in Evidence the Thickness and Structure of the Filling of Dayet Iffer (Middle Atlas, Morocco)[END_REF], who confirmed an upper Pleistocene age at the base of the upper terrace lacustrine chalk formations to the east (29,360+/-490 BP). Traces of nesting of highly oxidized and pedogenized peaty lacustrine formations, rich in Neolithic flints and shards, are identified in the middle part of the beine.

First geochemical and magnetic analyses of detrital formations stored in the lake reflect the nature of the dolomite bedrock and from forest developed soils (Rhoujati et al. 2012, Damnati et al. 2015). These preliminary studies describe warm and dry climate (6500-4600 cal. BP), wetter climatic conditions with high lake level (4600-2000 cal. BP), increasing pastoral and agricultural activities (e.g. Figure 1E) caused the decline of forest linked to increased soil erosion from 2,000 years.

Material and methods

Archeological context and Geomorphology of the site

The new field study conducted at Lake Iffer combined surveys of natural sections (from regressive erosion gullies) and a transect of six cores (from 3 to 6m), carried out with a "Cobra" thermic corer, which complete a series of three deep cores (10m) located in the middle of the lake, which have been the subject of sedimentological analyses and a palynological study [START_REF] Damnati | Sedimentology and geochemistry of lacustrine terraces of three Middle Atlas lakes: Paleohydrological changes for the last 2300 cal BP in Morocco (western Mediterranean region)[END_REF][START_REF] Rhoujjati | Significations paléoenvironnementales des dépôts du remplissage holocène du lac Iffer (Moyen Atlas, Maroc)[END_REF]. The 500-cm-long sediment core IF-C1 was extracted from the eastern shore of the lake (Figure 1C).

On IF-C1, six accelerator mass spectrometry radiocarbon dates were measured on charcoals at the Artemis-Lyon/Saclay and Poznan Radiocarbon Laboratory (Table S1). We used a Bayesian approach implemented in the new version of ChronoModel (Lanos & Dufresne, 2022) and the calibration data set IntCal20 [START_REF] Reimer | The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0-55 cal kBP)[END_REF] to estimate an average age-depth curve (MCMC; 3,000,000 iterations, SI, Figure S1). From the age-depth curve obtained by ChronoModel 3.2.2, the sediment accumulation rate was estimated. The estimated curve with a confidence interval allows to calculate a date interval whatever the depth (posterior probability density region HPD at a given confidence level (95%)) and an age (Mode A Posteriori) was assigned for each sample (Table S2).

7

This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d This core was sampled every 10 cm for pollen analyses, and was passed through the core scanner for XRF analysis every centimeter. Hydroclimatic fluctuations have succeeded one another leading to the oscillation of lake levels for more than 6 millennia, visible on both sides of the lake, by the alternation between silty-organic and chalky facies. The yellowish sandy or silty facies, more or less rubefied, testify to more detritic phases, connecting the slopes and the lake. The samples were collected between 2.3 and 3.03m depth, i.e. according to the age-depth model between 4,600 and 3,900 BP (late Neolithic-early Bronze Age). This part of the core corresponds globally to a period of higher water levels (positive water balance), associated with lacustrine deposits containing numerous carbonate biomarkers (tubes and plates) (Figure 1D).

To document human occupation near the lake, fifteen windows of archaeological survey were carried out over 1.5 to 2 ha with the support of a GPS on the eastern terrace of the lake, rich in chipped flints, with scattered ceramics on the surface. Three sectors indicate an occupation of the Epipaleolithic period (flakes with cut edges and bladeletts also pointed by abrupt retouches).

Five other sectors indicate a debitage rather of Mesolithic age (with segments of circle, unidirectional nuclei with negatives of narrow bladeletts). Eight places show evidence of Neolithic occupation sensu lato. The presence of larger flint pieces with more imposing modules indicates productions attributable to a Late Neolithic, possibly corroborated by the presence of some beige ceramic shards with incised decorations of the campaniform culture type (study in progress R. Guilbert-Berger). Concentrations of more recent ceramics (nonturned and turned) testify to proto-historic to antique human occupations (studies in progress).

Palynological analysis

A total of 48 samples have been studied in Iffer-C1 core sequence. The chemical treatment of the samples has been carried out following the so-called classical method [START_REF] Burjachs | Paléoenvironnement et paléoclimatologie de la Catalogne durant près de 30 000 ans (du Würmien ancien au début de l'Holocène) d'après la palynologie du site de l'Arbreda (Gérone, Catalogne)[END_REF][START_REF] Faegry | Textbook of pollen analysis[END_REF][START_REF] Girard | Nouvelles techniques de préparation en palynologie appliquées à trois sédiments du Quaternaire final de l'Abri Cornille (Istres, B. du Rh.)[END_REF][START_REF] Goeury | À propos de la concentration du pollen à l'aide de la liqueur de Thoulet dans les sédiments minéraux[END_REF][START_REF] Moore | Pollen analysis[END_REF], resulting in a final portion of the sediment preserved in glycerin gelatin (detailed in SI). An optical microscope (Nikon Eclipse 50i model), with 40X, 60X and 100X objectives, the latter with immersion oil, has been used for the identification of the pollen and non-pollinic microfossils. The reference collection of the Environmental Archaeology Research Group of the CSIC (Madrid), in addition to various bibliographic sources on the morphometric characterization of palynomorphs have been used 8 This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d for the identification of pollen morphotypes [START_REF] Bonnefille | Pollens des savanes d'Afrique orientale / Raymonde Bonnefille et Guy Riollet[END_REF][START_REF] Moore | Pollen analysis[END_REF][START_REF] Moore | Pollen and Spores: Patterns of Diversification[END_REF][START_REF] Moore | An Illustrated Guide to Pollen Analysis[END_REF][START_REF] Reille | Pollen et spores d'Europe et d'Afrique du Nord[END_REF][START_REF] Reille | Pollen et spores d'europe et d'afrique du nord[END_REF].

Non-pollen microfossils (algal spores, cyanobacteria, fungal spores and talus remains, fungal bodies of fungi, fragments of bryophytes or pteridophytes, animal micro-species, microfossils of unknown biological nature, etc.) were also identified based on abundant bibliographic references [START_REF] Bakker | A palaeoecological study of a late holocene section from "Het Ilperveld", western Netherlands[END_REF][START_REF] Lopez-Saez | Remarques paleoecologiques a propos de quelques palynomorphes non-polliniques provenant de sediments quaternaires en France[END_REF][START_REF] Pals | Paleoecological studies in the Klokkeweel bog near hoogkarspel (prov. of Noord-Holland)[END_REF][START_REF] Pantaleon-Cano | Signicado de Pseudoschizaea en las secuencias sedimentarias de la verti-ente mediterranea de la Peninsula Iberica e Islas Baleares[END_REF][START_REF] Sáez-López | Aplicación de los microfósiles no polínicos en Palinología Arqueológica[END_REF][START_REF] Van Geel | A palaeoecological study of holocene peat bog sections in Germany and The Netherlands, based on the analysis of pollen, spores and macro-and microscopic remains of fungi, algae, cormophytes and animals[END_REF][START_REF] Van Geel | Environmental reconstruction of a Roman Period settlement site in Uitgeest (The Netherlands), with special reference to coprophilous fungi[END_REF][START_REF] Van Geel | Palaeoecology and stratigraphy of the lateglacial type section at Usselo (the Netherlands)[END_REF][START_REF] Van Geel | A palaeoecological study of an upper late glacial and holocene sequence from "de borchert[END_REF]. For the elaboration of the pollen diagram, hydro-hygrophilic taxa, non-pollen microfossils, as well as Aster type, Cardueae and Cichorioideae have been excluded from the base sum, due to their zoophilic character being usually overrepresented [START_REF] Bottema | The interpretation of pollen spectra from prehistoric settlements (with special attention of Liguliflorae)[END_REF][START_REF] López-Sáez | Arqueopalinología: síntesis crítica[END_REF][START_REF] Sáez-López | Aplicación de los microfósiles no polínicos en Palinología Arqueológica[END_REF]. The relative percentage of these excluded palynomorphs has been calculated with respect to the total sum.

In this study we describe results (Table S3) of the four samples (at 300, 279, 250 and 236 cm depth) that coincide with ancient DNA (aDNA) samples.

Ancient DNA analysis

The entire Iffer-C1 core was opened in a dedicated room in the Palgene platform (ENS Lyon). DNA samples were taken each nine centimeters. We first scraped the sediment surface using sterile scalpels (5-10mm), then sampled inner uncontaminated sediments with a new sterile scalpel and transferred them to sterile tubes. Subsampled sediment was stored at -20°C for subsequent extractions. For this study, four samples were chosen for analysis (Figure 1D, Table S2). All the extractions were then conducted on the P2GM platform (MNHN Paris) equipped with specialized facilities devoted to aDNA analysis.

The four extractions of sedaDNA were performed from 100 mg of sediment (+/-10%), in one batch, including one extraction blank following Dabney et al (2013) protocol (detailed in SI).

We prepared libraries following a slightly modified protocol from [START_REF] Meyer | Illumina sequencing library preparation for highly multiplexed target capture and sequencing[END_REF] using the double indexing strategy of [START_REF] Kircher | Double indexing overcomes inaccuracies in multiplex sequencing on the Illumina platform[END_REF] (detailed in SI).

All samples underwent enrichment using custom probes (MyBaits custom design) designed to target 19 mammal and 22 plant taxa (Table S4, SI). The enrichment utilized complete mitogenome for mammals and matk, rbcl, and trnl-trnt chloroplast loci for plants. Libraries were captured per batch of two following the MYbaits manual V3, with 48 hours hybridisation at 56°C. The captures were amplified using KAPA Hi-Fi polymerase following the MyBaits 9 This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d manual instructions. Captured libraries were all sequenced in paired-end on a partial Illumina NovaSeq 6000 S4 XP lane (300 cycles, PE 150).

Reads were processed through the Paleomix pipeline [START_REF] Schubert | Characterization of ancient and modern genomes by SNP detection and phylogenomic and metagenomic analysis using PALEOMIX[END_REF], (Table S5) allowing 1) adapters removal, read pairing and merging, and sequence filtering using AdapterRemoval [START_REF] Lindgreen | AdapterRemoval: easy cleaning of next-generation sequencing reads[END_REF] (min length reads>=35bp, trimns: yes, triml qualities: yes, mm: 5); 2) duplicates filtering and 3) reads mapping [START_REF] Li | Fast and accurate short read alignment with Burrows-Wheeler transform[END_REF], (BWA aln; -l 1024; -o 2; -n 0.01) against a database comprising one sequence per genus and targeted loci (retaining the longest sequence) from available mammal and viridiplantae in the GenBank Database (march 2020). Reads were secondary analyzed with Prinseq [START_REF] Schmieder | Quality control and preprocessing of metagenomic datasets[END_REF] to remove low complexity sequences (-lc_method dust -lc_threshold 7 -trim_tail_left 5 -trim_tail_right 5). Bam files were filtered with samtools [START_REF] Danecek | Twelve years of SAMtools and BCFtools[END_REF]) using tag "X0:i:" to generate two sequence files, one with unique best hit and one with multiple best hit. All reads with matches were identified through DNA homology searches using BLAST [START_REF] Altschul | Basic local alignment search tool[END_REF] against the nr database (08/2022) to validate or determine the best taxonomic assignment.

Significant homologies obtained by Blast (best query cover and e-value) that refer to a single taxon are retained. If scores are equivalent for multiple taxa, the taxonomic rank is adjusted until a clear result is obtained (from genus to family depending on the case). To achieve precise and unambiguous taxonomic classification, biocurators performed this analysis manually. Taxa present in the control (extraction blank: sample without DNA) were excluded from the study and regarded as experimental contamination.

Mosses, ferns, algae and hornworts were not included in this study. We have selected taxa that represent more than 1% of the total number of reads attributed to plant or mammal taxa in at least one of the four samples studied (Table S6). However, taxa that do not fill the 1% criterion but described in the pollen analysis (Table S6) were added in figure 2. Given the capture design and the results obtained for both sedaDNA and palynology, we have chosen the following four categories: mammals, trees, aquatic plants and terrestrial plants. The relative evolution of the proportion of each taxon (>1% of total reads assigned) is then considered intra-categories (normalized in %, Figure 2). The results were illustrated as charts using R version 4.2.2 (2022-10-31) via Rstudio version 2022.12.0+353 and ggplot2, hrbrthemes and dlpyr packages.

Finally, sedaDNA deamination pattern and fragment length distributions were inspected with mapDamage2 [START_REF] Jónsson | mapDamage2.0: fast approximate Bayesian estimates of ancient DNA damage parameters[END_REF] for taxa with sufficient read counts after mapping of the reads against each reference genomes (Table S7, Figure S3).

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This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d

Results and Discussion

Landscape dynamics

At the molecular level, less than 1% of total sequences could be assigned (Table S5). In sample SL383394 at 302cm depth, showed no identified mammals, and very low number of plant reads (n=161) (Table S2, S6), reaching a maximum of four reads for taxa of interest. For this reason, the relative proportions of plant families for this sample are biased and difficult to interpret and we decided to not present and discuss sedaDNA results for this sample. This period corresponds to one of the four arid abrupt events identified around 4.5-4.4 ka BP, in Lake Tigalmamine (about 100 km from Lake Iffer, El Hamouti, 2014). The dates also mark the end of Lake Iffer's initial filling and the existence of a shallow water body due to low water inputs, with very high carbonate content [START_REF] Rhoujjati | Significations paléoenvironnementales des dépôts du remplissage holocène du lac Iffer (Moyen Atlas, Maroc)[END_REF]. This high alkalinity, combined with aridity, may have led to greater DNA degradation, as already reported in other studies [START_REF] Capo | Lake Sedimentary DNA Research on Past Terrestrial and Aquatic Biodiversity: Overview and Recommendations[END_REF]. This deficiency of DNA may explain the low sequencing yields for this sample (approximately 4 to 30 times less sequences than the other three samples, Table S5) and the difficulties in taxonomic identification. [START_REF] Parducci | Ancient plant DNA in lake sediments[END_REF]. Sequenced DNA quantities for the three other samples are adequate (Table S5). They indeed cover the 4.3-3.9 ka BP period, that corresponds to declining carbonate contents and temperatures in Lake Iffer, due to rising lake water levels linked to wetter conditions. Regional references also indicate episodes of low lake levels with reduced precipitation/evaporation ratio during this time [START_REF] Rhoujjati | Significations paléoenvironnementales des dépôts du remplissage holocène du lac Iffer (Moyen Atlas, Maroc)[END_REF].

Three major genera of trees (Pinus, Quercus and Arbutus) can be clearly identified within sedaDNA during the considered period (Figure 2A, Table S6). Pinus and Quercus are currently present on the site and their DNA as well as pollen remains are present throughout the period studied. Arbutus is only detected by sedaDNA analysis at 4,371 cal. BP (30% of the tree and shrub population) before drastically decrease. Its presence is in accordance with a previous study at Benzú Cave, located in the northernmost tip of the Tingitan Peninsula, 360 kilometers north of Iffer Lake, where it was used as fuel together with Quercus sp., Olea sp., Fraxinus sp.

among others [START_REF] Muñoz | Las sociedades tribales neolíticas en la zona litoral e interior de Cádiz. Continuidad poblacional y proceso histórico[END_REF][START_REF] Vijande-Vila | The occupation of Benzú Cave (Ceuta) by Neolithic and Bronze Age Societies[END_REF]. Its absence in the pollen register could be explained by its entomophilous pollination, the fact that Arbutus is a poor pollen producer since its mode of pollination is autogamy [START_REF] Hagerup | Wind autogamy in Arbutus[END_REF][START_REF] Faida | Genetic diversity and structure of natural populations of Arbutus unedo across altitude, bioclimate and geographical origin as revealed by ISSR markers[END_REF] 0 3 6 9 0 3 6 9 0 3 6 9 0 3 6 9 0 3 6 9 0 3 6 9 0 3 6 9 0 3 6 9 0 3 6 9 0 3 6 9 0 3 6 9 0 3 6 9 279 (-4,371) 252 (-4,133) 236 (-3,992) Portion in % Depth in cm (Age in years CAL. BP) Iffer lake between Late Neolithic to Bronze Age among four groups: A) trees and shrubs, B) herbs, C) aquatic plants and D) mammals; and E) : relative proportions of tree/herbs/aquatic plants identified. In A, B, C and D panels: Up: Relative proportion of each plant family/genus among all assigned plant/ mammal reads -for which the number of reads >1% of the total number of reads assigned to either plant or mammal taxa in at least one sample or present in the pollen records ; bottom: relative proportion of the main plant and mammal taxa assigned (>1%); red: Plant taxa for which the percentage is <1% and identified in pollen remains. This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d because its pollen is large and heavy and does not travel far from the tree and, moreover, it is similar to other pollens of the Ericaceae family and difficult to distinguish [START_REF] Almeida | Prediction scenarios of past, present, and future environmental suitability for the Mediterranean species Arbutus unedo[END_REF].

Nowadays in Morocco, Arbutus occurs in scrublands, oak forests, and dense maquis. Its density depends on a gradient with densest populations where the climate is subhumid to humid as this species prefers fresh, well-drained soils [START_REF] Wahid | Ethnobotanical uses and distribution status of Arbutus (Arbutus unedo L.) in Morocco[END_REF]. However, Arbutus shows strong resistance to hard environmental conditions and has the ability to regenerate after forest fires (El Haouari et al, 2021). The significant decline in its population, in proportion to that of Quercus and Pinus after 4.2 ka BP could be explained by the so-called "4.2 cal. ka BP event"

corresponding to an interval of cooling and drying conditions [START_REF] Bini | The 4.2 ka BP Event in the Mediterranean region: an overview[END_REF]. During this period, the percentages of tree pollen show, in Morocco, a moderate increase in tree cover between 4.5 and 4.2 ka BP followed by a decline, creating an opening of the forests between 4.2 and 3.9 ka BP (di Rita et al, 2022). As Arbutus is part of the understory vegetation and its growth has been shown to be inversely related to the presence of holm oak [START_REF] Badal | Vegetation changes and human action from the Neolithic to the Bronze Age (7000-4000 B.P.) in Alicante, Spain, based on charcoal analysis[END_REF],

we can hypothesize that the growth of the forest cover between 4.5 and 4.2 ka BP, followed by its opening, also observed with our sedaDNA results, is one of the causes of the decline of this species after 4.2 ka BP.

This forest development around the 4.2 ka BP event is clearly evidenced by our Iffer Lake sedaDNA analysis. The proportion of tree DNA increases from 12% to 30% between 4.3 ka and 4.1 ka BP and then stabilizes (Figure 2E). This dominant association of Quercus and Pinus is also corroborated by palynological analyzes which confirm that this Pinus-Quercus mixed forest ecosystem is well developed during this period (Table S3, Figure 3). They are associated with Olea europea around 4.5 ka BP and then riparian taxa at 4.3 ka BP (Alnus and Fraxinus)

while Cedrus remains constant. We first observe a predominant presence of Quercus, that decline together with Cedrus or Olea europea, indicating some deforestation around 4.1 ka BP.

This episode is followed by a re-expansion of oak forests at 3.9 ka BP and Olea europaea and the progressive disappearance of riparian taxa, (Figure 2A, Figure 3). This significant disturbance in the relative composition of mixed oak and pine forests between 4.1 and 3.9 ka BP could be attributed to drought but also probably to possible fires. In Ait Ichou, 70 km from Ifter lake, the number of micro-charcoals increased considerably after ~4.5 ka BP with maximum values between ~3 and 1.5 ka BP [START_REF] Tabel | Impacts des changements environnementaux pas-sés durant le Quaternaire récent sur la dynamique forestière duMoyen Atlas marocain[END_REF]. As human activities in the Middle Atlas were rather minor until ~2-1.5 ka BP [START_REF] Cheddadi | A History of Human Impact on Moroccan Mountain Landscapes[END_REF][START_REF] Tabel | Impacts des changements environnementaux pas-sés durant le Quaternaire récent sur la dynamique forestière duMoyen Atlas marocain[END_REF], these fires are likely of natural origin, given the more arid environment. A recent study, carried out in the northeast of Spain, shows that, while these two species regenerate effectively after fire, Pinus recolonizes disturbed areas via seedlings, whereas Quercus regrows vigorously after 13

This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d disturbances. Therefore, in mixed forests, even small-scale fires can lead to significant probabilities of transitioning from mixed forests to monospecific forests, with Quercus dominating at higher altitudes and Pinus at lower altitudes, particularly in drier and warmer conditions [START_REF] Broncano | Predicting the Recovery of Pinus halepensis and Quercus ilex Forests after a Large Wildfire in Northeastern Spain[END_REF]. We can therefore hypothesize that the relative deforestation and the decrease in Pine DNA in favor of oak DNA between 4.1-3.9 ka BP would correspond to the consequence of fires, themselves linked to an episode of drought.

At Dayat Hachlaf, a few kilometers from lake Iffer, Quercus and Pinus forest contingencies have been recorded since 6 ka BP, with a noticeable change in forest composition around 3.5 ka BP [START_REF] Nourelbait | Climate change and ecosystems dynamics over the last 6000 years in the Middle Atlas, Morocco[END_REF]. These Quercus-Pinus variations were not really recorded via the palynological study. Pinus is a well-known quantitatively and extensively dispersed pollen producer [START_REF] Poska | Pollen dispersal and deposition characteristics of Abies alba, Fagus sylvatica and Pinus sylvestris, Roztocze region (SE Poland) -Veg[END_REF]López-Sáez et al., 2013), dominating Iffer lake record and complicating the correlation between its presence on the site and its pollen abundance [START_REF] Bell | Modern surface pollen assemblages from the Middle and High Atlas, Morocco: insights into pollen representation and transport[END_REF], well in less proportion. Other trees are detected by the pollen (Cupressaceae, Cedrus, Olea europea and riparian taxa (Fraxinus), only found as traces for some of them among sedaDNA data, indiscernible among other representatives of the same families (co-best hits and <2% of assigned reads). This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d 2B). We noticed a slight variation in the proportion of these taxa over time where Fabaceae is the most abundant around 4.3 ka BP whereas Asteraceae dominates at 4.1 ka BP in detriment of other families, and in association with other ruderal taxa in the palynological record (Plantago lanceolata, Rumex, Medicago; Figure 3). The palynological rests are dominated by Poaceae, showing probably the presence of grasslands in the vicinity.

Finally, we could determine two major genera of aquatic plants among sedaDNA sequences (Figure 2C, Table S6): Myriophyllum (Haloragaceae) and Ceratophyllum (Ceratophyllaceae), along with low amount of Ruppia (Cymodoceae) and Carex (Cyperaceae). Myriophyllum and Carex were also determined in palynological remains with the same relative evolution of their proportion (Figure 3). As already demonstrated in previous studies, aquatic plants, which grow in and around the lake, dominate the assemblage (Figure 2E) to the detriment of terrestrial plants which are often under-represented [START_REF] Birks | The importance of plant macrofossils in the reconstruction of Lateglacial vegetation and climate: examples from Scotland, western Norway, and Minnesota, USA[END_REF][START_REF] Alsos | Plant DNA metabarcoding of lake sediments: How does it represent the contemporary vegetation[END_REF]. Myriophyllum appears in the pollen record of the four samples with constant values of 4-9% (Figure 3), indicating a stable presence throughout this time, as well as shallow and somewhat eutrophic waters. sedaDNA results (Figure 2C, Table S6) show a decrease of Ruppia and Carex over the time since these two species, represent respectively 3.7% and 4.6% of aquatic plants at 4.3 ka BP then pass to the state of traces.

Myriophyllum dominated in the lake during the whole studied period even if we observe, at 4,133 cal. BP, an increase of the proportion of Ceratophyllum sp. Myriophyllum and Ceratophyllum are two species of submerged macrophytes with common characteristics (fast growth, low preference for light). However, Myriophyllum is a rooted species, while

Ceratophyllum does not form roots and is found free-floating. Consequently, nutrient uptake by Ceratophyllum is almost entirely foliar whereas Myriophyllum can absorb nutrients from sediments and the water column, thereby limiting nutrients available to floating plants [START_REF] Cao | Interactions between submerged and floating plant species with different types of nutrient uptake in sand and fertile sediments[END_REF]. Although Nourebailt et al ( 2016) seems to denote that the proportion of aquatic plants cannot be used as indicators of lake level variations but only presence of water in the site, a paleoecological analysis of the macro-remains of Lake Iffer for 6000 years (Middle Atlas, Morocco, [START_REF] Huillery | Evolution de l'hydroécosystème du lac Iffer depuis 6000 ans (Moyen Atlas, Maroc) : analyse paléoécologique des macro-restes[END_REF] shows, between 4,350 and 3,320.5 cal. BP, a progressive installation of relatively humid conditions. Same study pointed out abundance of microcharcoals between 4.1-3.9 ka BP that testifies local fires (which corroborates our hypothesis concerning the cause of the Quercus-Pinus shift). We can hypothesize that Ceratophyllum benefited from favorable conditions (light, dissolved nutrient) at 4.1 ka BP but that then, plant degradation following fires and humidification of the environment favored Myriophyllum. This hypothesis corresponds to the observations showing that, in Lake Iffer, between 4.6 and 3.6 ka BP, the 15 This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d organic matter content marks a very significant return in terms of contribution compared to the previous period [START_REF] Rhoujjati | Significations paléoenvironnementales des dépôts du remplissage holocène du lac Iffer (Moyen Atlas, Maroc)[END_REF].

In total, all taxa identified by pollen were retrieved in sedaDNA (sometimes as traces) but sedaDNA identified seven taxa absent in pollen (Ericaceae, Convolvulaceae, Fabaceae, Lamiaceae, Rosaceae Ceratophyllaceae and Cymodoceae), either because pollen diffusion mode (anemogamy and entomogamy) or low quantity of pollen produced and/or detected. The absence of total overlap between the two approaches as well as the relative differences between trees/shrubs and herbaceous is not surprising. Pollen reflects local and regional landscape while sedaDNA explain local vegetation variation [START_REF] Capo | Lake Sedimentary DNA Research on Past Terrestrial and Aquatic Biodiversity: Overview and Recommendations[END_REF], Parducci, 2013, 2019).

Altogether, results indicate an environment dominated by evergreen oak and Poaceae. Around 4.3 ka BP, increased environmental humidity is characterized by the rise of Fraxinus and Cyperaceae. This precedes a relative opening of the environment, between 4.1-3.9 ka BP, with relative deforestation, the gradual disappearance of riparian taxa and the decrease in Pine in favor of oak. This may have resulted from a drought episode, possibly linked to the "4.2 ka cal.

BP event." Additionally, we observe greater anthropic pressure during the same period, as evidenced by the presence of ruderal taxa.

Evidence of increased anthropization and pastoralism

Morocco, especially the Western Maghreb, is the most well-dated and documented region of Mediterranean Africa (excluding Egypt) between 6,000-2,900 years BP. However, information remains scarce, particularly about the ways of life that supported people in this area during the preceding fourth and early third millennia BP [START_REF] Lucarini | New Light on the Silent Millennia: Mediterranean Africa, ca. 4000-900 BC[END_REF].

Among sedaDNA sequences, the major part of mammal reads mapped on Elephantidae and Bovidae mitogenomes. Two main genera identified within Bovidae are Ovis and Bos, but differentiation between the two genera was not always possible due to the similarity of the genomic regions mapped to the reads. In the palynological record, in sample 300, fungal ascospores of coprophilic ecology (Sordaria sp., Figure 3), a fungi that develop in animal excrement, have been identified (van Geel, 1978, López Sáez and[START_REF] López Sáez | Coprophilous fungi as a source of information of anthropic activities during the prehistory in the Amblés Valley (Ávila, Spain): The archaeopalynological record[END_REF]. Its scarce dispersion undoubtedly determines the existence of animals on a local scale. Domesticated animals, mainly caprines and cattle (all already present during the eighth-seventh millennia BP), remained widely attested throughout Mediterranean Africa. In Western 16

This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d

Maghreb, their presence is reported in coastal sites during the early to mid-sixth millennium BP with evidence of cattle, caprines, and pigs [START_REF] Linstädter | Defining the Early Neolithic of the Eastern Rif, Morocco -Spatial distribution, chronological framework and impact of environmental changes[END_REF][START_REF] Morales | The origins of agriculture in North-West Africa: macro-botanical remains from Epipalaeolithic and Early Neolithic levels of Ifri Oudadane (Morocco)[END_REF][START_REF] Schmieder | Quality control and preprocessing of metagenomic datasets[END_REF]. Later, the site of Oued Beh (late sixth millennium BP), indicates a possible socially complex agricultural society [START_REF] Rus | Las cerámicas neolíticas pintadas en Andalucía y sus contextos arqueológicos[END_REF]. Evidence of pastoral activity and crop cultivation remains diffuse for the first half of the fifth millennium BP [START_REF] Lucarini | New Light on the Silent Millennia: Mediterranean Africa, ca. 4000-900 BC[END_REF]. Finally, during the fourth millennium BP until the start of the third millennium BP only few remains attest of pastoral way of life with the presence of domestic cattle and caprines [START_REF] Wengler | Evénements et chronologie de l'Holocène en milieu continental au Maghreb. Les données du Maroc oriental.[Holocene events and chronology in the continental environment of the Maghreb[END_REF][START_REF] Wengler | Vegetation, sedimentary deposits and climates during the Late Pleistocene and Holocene in eastern Morocco[END_REF]).

Here we evidence, for the first time, presence of Bovidae on the Iffer site, since 4,371 cal. BP and continuously during at least 380 years. The site and the approach to the lake as an access to the water could have constituted a favorable environment for grazing. We observe the proportion of this taxa increasing since 4,133 cal. BP at the expense of the Elephantidae, detected since 4,371 cal. BP before disappearing 140 years later (Figure 2D). This corresponds to a slight landscape opening and increased human influence, marked by the presence of ruderal taxa. However, there is no indication of cultivated plant taxa at this site. This is not unexpected as it is well-established that agriculture was delayed in most of Mediterranean Africa, due to pastoral groups that have traditionally exhibited robust and resilient lifestyles, influenced by Saharan foraging and pastoral practices [START_REF] Lucarini | New Light on the Silent Millennia: Mediterranean Africa, ca. 4000-900 BC[END_REF]. Also, these populations probably exploited wild plants such as acorns, pine nuts, and arbutus [START_REF] Barker | The Cyrenaican Prehistory Project 2010: the fourth season of investigations of the Haua Fteah cave and its landscape, and further results from the 2007-2009 fieldwork[END_REF][START_REF] Barker | The Cyrenaican Prehistory Project 2009: the third season of investigations of the Haua Fteah cave and its landscape, and further results from the 2007-2008 fieldwork[END_REF][START_REF] Morales | The contribution of botanical macro-remains to the study of wild plant consumption during the Later Stone Age and the Neolithic of north-western Africa[END_REF][START_REF] Morales | First preliminary evidence for basketry and nut consumption in the Capsian culture (ca. 10,000-7500 BP): Archaeobotanical data from new excavations at El Mekta, Tunisia[END_REF] that were crucial sources of food along the Saharan belt [START_REF] Dunne | Earliest direct evidence of plant processing in prehistoric Saharan pottery[END_REF][START_REF] Lucarini | Exploitation and management of wild grasses at Hidden Valley, Farafra Oasis[END_REF][START_REF] Mercuri | Plant behaviour from human imprints and the cultivation of wild cereals in Holocene Sahara[END_REF][START_REF] Wasylikowa | Site E-75-6: Vegetation and Subsistence of the Early Neolithic at Nabta Playa, Egypt, Reconstructed from Charred Plant Remains[END_REF], and the Mediterranean coast [START_REF] Lucarini | The exploitation of wild plants in Neolithic North Africa. Use-wear and residue analysis on non-knapped stone tools from the Haua Fteah cave, Cyrenaica, Libya. Neolit. Sahara South[END_REF] even during Neolithic.

Presence of Elephantidae is impacted by anthropic pressure and climatic variations

The presence of elephants is attested by sedaDNA identified in two of the four samples, spanning 140 years (from 4,371 to 4,133 cal BP, Figure 2D). This detection is noteworthy as elephants was not a targeted taxon in the capture. Unlike plants, detecting animals through sedaDNA is often challenging and incomplete, given the limited traces they leave. Thus, their detection suggests a significant population on the site, sufficient for their DNA to be deposited and later detected thousands of years later [START_REF] Giguet-Covex | New insights on lake sediment DNA from the catchment: importance of taphonomic and analytical issues on the record quality[END_REF].

This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d

In the Plio-Pleistocene, proboscidean species in Morocco include the genera Anancus, Mammuthus (the species M. africanavus) and Elephas. In Morocco, Elephas taxa include the species Elephas recki Dietrich 1915, a widespread Pleistocene African species that ranged from Eritrea (Martínez-Navarro, 2010) to the Atlantic coast of Morocco [START_REF] Arambourg | Vertébrés villafranchiens d'Afrique du Nord : artiodactyles, carnivores, primates, reptiles, oiseaux[END_REF] and the species Elephas iolensis excavated from the mid-pleistocene Anchrif fossil site [START_REF] Marinheiro | New Quaternary fossil sites from the Middle Atlas of Morocco[END_REF][START_REF] Ouchaou | Les grands mammifères disparus du Maroc durant l'Holocène[END_REF]. These specialized grazing species became extinct in the Middle-Upper Pleistocene [START_REF] Manthi | Late Middle Pleistocene Elephants from Natodomeri, Kenya and the Disappearance of Elephas (Proboscidea, Mammalia) in Africa[END_REF], likely due to the intensity and increasing rate of climatic fluctuations, which favored the generalist and mixed feeder Loxodonta africana.

The subspecies Loxodonta africana pharaohensis, also called Atlas elephant, was present in North Africa and therefore in Morocco, until its extinction in Roman times. In particular, the 'African Humid phase' in North West Africa (c.10.5-5.5 ka cal BP) offered favorable conditions permitting its far wide distribution [START_REF] Schuhmacher | Ivory exchange networks in the Chalcolithic of the Western Mediterranean, in: Key Resources and Sociocultural Developments in the Iberian Chalcolithic[END_REF].

The exact determination of the genus and the species of Elephantidae at Iffer site was impossible due to the similarity of the genomic regions mapped to the reads in both Elephas and Loxodonta genus. Although paleontological evidence suggests the absence of Elephas genus in this region during that period, we could hypothesize they could belong to Loxodonta taxa. Moreover, none of the reads attributed to Elephantidae matches 100% with the available sequences of current representatives (mitogenomes available for seven different species). It suggests that these sequences could be attributed to a species not represented in the current databases and therefore possibly ancient, as it is the case for Loxodonta africana pharaohensis.

During the Neolithic and Bronze Age period, the presence of elephants in Morocco has been documented through various archaeological artefacts and rock art (eg: petroglyph of an elephant, cave site of Aït Ouazik, late Neolithic, engravings of Hassi Ghilan; [START_REF] Boudouhou | Éléphants et personnages dans les gravures rupestres de Hassi Ghilan (Maroc oriental)[END_REF][START_REF] Daugas | Le néolithique du Maroc, 25 ans de coopération franco-marocaine. Évolution des concepts[END_REF][START_REF] Schuhmacher | Ivory exchange networks in the Chalcolithic of the Western Mediterranean, in: Key Resources and Sociocultural Developments in the Iberian Chalcolithic[END_REF]. While these representations and archeological elements could testify of their environment, of the richness of the fauna in the Atlas and of the use of elephants (hunting, transportation, trade, ivory) [START_REF] Daugas | Le néolithique du Maroc, 25 ans de coopération franco-marocaine. Évolution des concepts[END_REF][START_REF] Fregel | Ancient genomes from North Africa evidence prehistoric migrations to the Maghreb from both the Levant and Europe[END_REF][START_REF] Schuhmacher | Ivory exchange networks in the Chalcolithic of the Western Mediterranean, in: Key Resources and Sociocultural Developments in the Iberian Chalcolithic[END_REF], the scarce number of objects and remains in Morocco do not allow to fully understand their exploitation and incorporation in the human system and in this region during Neolithic and Bronze Age. Here, we both show archeological and biological evidence of human site occupation and of pastoralism 4,371 years ago, while elephants were present at Iffer site. Although we cannot presume human-elephant interactions, we can assume that these animals were indeed part of the anthropological system and could even be exploited. Their importance is attested, for example, by the existence, since the Chalcolithic, of African ivory exchange networks from the Maghreb to southwestern Spain and Portugal (Schuhmacher,18 This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d 2017). Its disappearance from sample 236 at 3,992 cal. BP, for which the plant biodiversity as well as the number of DNA sequences attributed to each taxon is similar to samples 279 and 252, could more likely be linked to both anthropic pressure and climatic variations. Their disappearance followed a period of warmer and drier climate leading to a decline of the forest and an opening of the landscape. Together with a possible exploitation of this species, the relative intensification of pastoralism and a change in land use (even if no agricultural practice was detected), their preferred environment could have been modified affecting their ability to survive.

Conclusion

Here, for the first time in Northern Western Maghreb, we employed both palynological and paleogenomic to reveal climate changes and human presence at Iffer lake from late Neolithic to Bronze Age. Archeological and biological results demonstrate evidence of pastoralism 4.3 ka years ago on this site. The intensification of anthropic pressure in this region precedes the environment opening between 4.1-3.9 ka BP possibly triggered by a drought episode linked to the so-called "4.2 ka cal. BP event". Both factors likely contributed to the local decline of Elephantidae, whose presence is attested through ancient sedimentary DNA.

Our results hold significant importance for the archaeological community. They not only shed light on the processes of anthropization in this region, but also provide valuable evidence of pastoral practices for a period poorly documented. Particularly noteworthy is the detection, for the first time through sedaDNA, of the presence of Bovidae and Elephantidae. It offers new perspectives for the exploration and study of these Mediterranean sites with scarce archeozoological material. An extensive analysis of the genomic data (including at the microbial level) is currently underway to gain a deeper understanding of the ecological changes of this site. This data will be complemented by a more comprehensive paleoclimatic study to facilitate a better interpretation of biodiversity changes.

Extending ancient sedimentary DNA analysis to more recent and arid periods, characterized by intensified anthropization and catchment detriticism, would be valuable in observing the evolution and response of DNA signatures and biodiversity. Additionally, a high-resolution coupled analysis between DNAs and pedosedimentary facies, as opposed to traditional sedimentology and geochemistry, could help discern the connection between the DNA signal and the stability/instability of slopes near Lake Iffer.

19

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This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d

Figure 1 :

 1 Figure 1: Geographic, topographic and lithostratigraphic data of the studied samples at Iffer lake (Morocco). A. Location of the study site in the Moroccan Middle Atlas mountains; B. Topographic restitution of the lake perimeter with position of the studied core; C. Panoramic view of the eastern shore of the lake with the position of the core (red star) and the steep western and northern wooded slopes; D. Photograph and lithostratigraphy of core-C1 with position of radiocarbon dates, ancient sedimentary DNA and pollen samples; E. Photograph of the lake's western shoreline during a low-water event in autumn 2022, with flocks of sheep and cattle.

  and 11This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d

Figure 2 :

 2 Figure2: Taxa assigned via sedaDNA analysis at Iffer lake between Late Neolithic to Bronze Age among four groups: A) trees and shrubs, B) herbs, C) aquatic plants and D) mammals; and E) : relative proportions of tree/herbs/aquatic plants identified. In A, B, C and D panels: Up: Relative proportion of each plant family/genus among all assigned plant/ mammal reads -for which the number of reads >1% of the total number of reads assigned to either plant or mammal taxa in at least one sample or present in the pollen records ; bottom: relative proportion of the main plant and mammal taxa assigned (>1%); red: Plant taxa for which the percentage is <1% and identified in pollen remains.

Figure 3 :

 3 Figure 3: Palynological diagram reconstituted from four samples at Iffer lake, covering a 380 years period (Late Neolithic to Bronze Age)

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Acknowledgments

This work has been supported by Rennes Métropole (scientific facility allowance) and MSHB (house of human sciences in Brittany). We thank the Palgene platform and the Paleogenomics and Molecular Genetics Technical Platform of the MNHN (P2GM) at "Musée de l'Homme'', in Paris. The bioinformatics analyses have benefited from the Genouest service at the University of Rennes. The sediment core acquisition, archaeological, pollen and radiocarbon studies were carried out under the Paleomex-Maghreb (CNRS INSU-INEE), APPI Transmar (Université Lyon 2) and PHC Toubkal (Campus-France) projects. We thank Nathan Martin, for his participation during his training for aDNA laboratory experiments, and Apolline Huillery, for

her contribution to the macro-rest analysis, as part of their master's internships. We also thank Jacob Enk and Brian Brunelle (Arbor Bioscience) for discussions upstream of the capture design and for the baits design.

Data availability: Raw genomic sequence data are available on request.

Declarations of interest:

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4534181 P r e p r i n t n o t p e e r r e v i e w e d