Rafael Marquina-Blasco

Ana Fagoaga

Vicente Crespo Roures

Salvador Bailon

Carolina Mallol

Cristo M Hernandez

Bertila Galván

Hugues-Alexandre Blain

Francisco Javier Ruiz-Sánchez

Vicente D Crespo

Cristo M Hernández

Francisco Javier Ruiz- Sánchez

Applying the UDA-ODA discrimination technique to a herpetological association: the case of the Middle Palaeolithic site of El Salt (Alcoi, Spain)

Keywords: Palaeoclimate, Late Pleistocene, Iberian Peninsula, Neanderthal disappearance, GIS, MER method

scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

INTRODUCTION

The use of fossil assemblages to propose palaeoclimatic reconstruction has been a constant since the very beginning of palaeontological studies [START_REF] Blain | Towards a Middle Pleistocene terrestrial climate reconstruction based on herpetofaunal assemblages from the Iberian Peninsula: state of the art and perspectives[END_REF]. As currently occurs, biological communities are not independent of the abiotic components [START_REF] Birks | Strengths and weaknesses of quantitative climate reconstructions based on Late-Quaternary[END_REF]. As a consequence of the changes and variations of these components, the composition and structure of the biological communities changes along the time [START_REF] Grayson | A critical view of the use of archaeological vertebrates in paleoenvironmental reconstruction[END_REF]. In this sense, several works have demonstrated the effects of the present impact that the current global climatic change is leading in many biological communities (i.e. [START_REF] Araújo | Climate warming and the decline of amphibians and reptiles in Europe[END_REF]. Of course, these changes are observable on the fossil record too [START_REF] Willis | Biodiversity baselines, thresholds, and resilience: testing predictions and assumptions using palaeoecological data[END_REF]). This "climatic response" and the current existence of modern relatives for calibration purposes, allow the use of fossil remains as palaeoclimatic proxies in accordance to the requirements proposed by [START_REF] Bradley | Paleoclimatology. Reconstructing Climates of the Quaternary[END_REF].

Two main groups can be distinguished in the palaeoclimate reconstruction methods based on biological samples: (i) qualitative methods and (ii) quantitative methods [START_REF] Birks | Strengths and weaknesses of quantitative climate reconstructions based on Late-Quaternary[END_REF]). In the first group, the palaeoclimatic reconstructions are presented in descriptive terms like warm, polar, wetter, cold or dry; without providing a numerical valuation to eliminate the ambiguity inherent in these descriptions [START_REF] Porch | Climate space, bioclimatic envelopes and coexistence methods for the reconstruction of past climates: a method using Australian beetles and significance for Quaternary reconstructions[END_REF]. The second group includes those that provide direct values to infer past environments [START_REF] Birks | Strengths and weaknesses of quantitative climate reconstructions based on Late-Quaternary[END_REF]. Different quantitative methods have been developed

for the reconstruction of past Quaternary climate using fossil faunal assemblages [START_REF] Birks | Strengths and weaknesses of quantitative climate reconstructions based on Late-Quaternary[END_REF]. One of them, the Mutual Climatic Range (MCR) was outlined by [START_REF] Atkinson | Climatic calibration of coleopteran data[END_REF][START_REF] Atkinson | Seasonal temperatures in Britain during the past 22,000 years, reconstructed from beetle remains[END_REF]. It is based in the assumption that a particular species has a known climatic tolerance range, thus if this species was present at a site in the past then the climate was included within its tolerance limits. Likewise, a group of species that cohabited at the same site and time is supposed that the palaeoclimate conditions must have situated in the combined climatic tolerance range of all the assemblage. MCR has been applied to a wide range of organisms, such insects [START_REF] Atkinson | Climatic calibration of coleopteran data[END_REF][START_REF] Atkinson | Seasonal temperatures in Britain during the past 22,000 years, reconstructed from beetle remains[END_REF][START_REF] Coope | The response of insect faunas to glacialeinterglacial climatic fluctuations[END_REF][START_REF] Elias | Quaternary Insects and Their Environments[END_REF][START_REF] Elias | The mutual climatic range method of palaeoclimatic reconstruction based on insect fossils: new applications and interhemispheric comparisons[END_REF][START_REF] Elias | Mutual climatic range reconstructions of seasonal temperatures based on Late Pleistocene fossil beetle assemblages in Eastern Beringia[END_REF][START_REF] Coope | Temperature gradients in northern Europe during the last glacial-Holocene transition (14-9 14 C kyr BP) interpreted from coleopteran assemblages[END_REF][START_REF] Elias | Insights on the climatic constraints on the beetle fauna of coastal Alaska, USA, derived from the Mutual Climatic Range method of paleoclimate reconstruction[END_REF][START_REF] Miller | Late-glacial climate in Maritimes Region, Canada, reconstructed from mutual climate range analysis of fossil Coleoptera[END_REF][START_REF] Alfimov | Possible errors of the mutual climatic range (MCR) method in reconstructing the Pleistocene climate of Beringia[END_REF], plants [START_REF] Sinka | A mutual climatic range method for reconstructing palaeoclimate from plant remains[END_REF][START_REF] Pross | Reconstructing palaeotemperatures for the Early and Middle Pleistocene using the mutual climatic range method based on plant fossils[END_REF][START_REF] Thompson | Quantitative estimation of climatic parameters from vegetation data in North America by the mutual climatic range technique[END_REF], terrestrial mollusc [START_REF] Moine | Mise en évidence d'événements climatiques rapides par les faunes de molusques terrestres des loess weichseilen de Nussloch (Allemagne)[END_REF] and ostracods [START_REF] Horne | A mutual temperature range method for Quaternary palaeoclimatic analysis using European nonmarine Ostracoda[END_REF][START_REF] Horne | Mutual Climatic Range Methods for Quaternary Ostracods[END_REF]. [START_REF] Blain | Contribution de la paléoherpétofaune (Amphibia & Squamata) à la connaissance de l'évolution du climat et du paysage du Pliocène supérieur au Pléistocène moyen d'Espagne[END_REF] proposed a modification of the MER methodology by using the current geographical distribution of the fossil assemblage to extrapolate the palaeoclimatic conditions to the palaeontological/archaeological site studied (Figure 1). Because MCR methodology is based in the climatic coocurrence of species assemblages, and not with the geographic sympatry area, [START_REF] Lyman | The mutual climatic range technique is (usually) not the area of sympatry technique when reconstructing paleoenvironments based on faunal remains[END_REF] proposed renaming the technique outlined by [START_REF] Blain | Contribution de la paléoherpétofaune (Amphibia & Squamata) à la connaissance de l'évolution du climat et du paysage du Pliocène supérieur au Pléistocène moyen d'Espagne[END_REF] such as UTM-MCR. In this way, [START_REF] Blain | Redefining upon the climatic background of the early Pleistocene hominid settlement in western Europe: Barranco Leon and Fuente Nueva-3 (Guadix-Baza basin, SE Spain)[END_REF] proposed the new name of Mutual Ecogeographic Range (MER) method. We prefer the second name by two reasons. Firstly, MER is a more intuitive name for a technique based on current geographical area occupied for a determined species. Secondly, the term MER has been used yet in various works (i. e. Blain et al. 2018 and references therein). Regarding to small vertebrates, MER method has been used with birds [START_REF] Núñez-Lahuerta | Avian remains from the Upper Pleistocene (MIS3) site of Aguilón P-7, south of the Ebro River, Spain[END_REF], herpetofauna [START_REF] Blain | Contribution de la paléoherpétofaune (Amphibia & Squamata) à la connaissance de l'évolution du climat et du paysage du Pliocène supérieur au Pléistocène moyen d'Espagne[END_REF][START_REF] Blain | Long-term climate record inferred from Early-Middle Pleistocene amphibian and squamate reptile assemblages at the Gran Dolina cave, Atapuerca, Spain[END_REF][START_REF] Blain | Climatic conditions for the last Neanderthals: Herpetofaunal record of Gorham's Cave, Gibraltar[END_REF]Marquina-Blasco et al. 2017, 2021), small mammals [START_REF] López-García | Évolution climatique durant le Pléistocène Supérieur en Catalogne (nordest de l'Espagne) d'après l'étude des micromammifères[END_REF], 2011;[START_REF] Fagoaga | Palaeoecological implications of Neanderthal occupation at Unit Xb of El Salt (Alcoi, eastern Spain) during MIS 3 using small mammals proxy[END_REF]Fagoaga et al. , 2019b)), and a combination of the two latter [START_REF] López-García | Environmental and climatic context of Neanderthal occupation in southwestern Europe during MIS3 inferred from the small-vertebrate assemblages[END_REF], 2021;[START_REF] Rey-Rodríguez | Last Neanderthals and first Anatomically Modern Humans in the NW Iberian Peninsula: Climatic and environmental conditions inferred from the Cova Eirós small-vertebrate assemblage during MIS 3[END_REF][START_REF] Connolly | A multiproxy record of palaeoenvironmental conditions at the Middle Palaeolithic site of Abric del Pastor (Eastern Iberia)[END_REF]. Several authors have already enumerated the weaknesses (and strengths) of the major approaches used to reconstruct past climate from biological proxies (e.g. [START_REF] Birks | Strengths and weaknesses of quantitative climate reconstructions based on Late-Quaternary[END_REF]. As advantages, the MCR and, by extension, MER methodology do not need sophisticated mathematical apparatus and the availability of an important database on the current distribution area of species (at least in the case of vertebrates) neither a significant amount of climatic data [START_REF] Alfimov | Possible errors of the mutual climatic range (MCR) method in reconstructing the Pleistocene climate of Beringia[END_REF]. As many other methods, the MER method follows actualism, because it relies on the current distribution of the species, assuming that the fossil representatives of the extant species have the same climatic tolerances and preferences as their living counterparts. However, there are known examples of species that have experienced a disruption of their ecological niche during their natural history, i. e. Microtus cabrerae [START_REF] Castellanos-Frías | Assessment of the effect of climate changes in the Late Pleistocene and Holocene on niche conservatism of an arvicolid specialist[END_REF]). However, this trouble is easily solved by considering in the study a suite of taxa with similar habitat preferences [START_REF] Grayson | A critical view of the use of archaeological vertebrates in paleoenvironmental reconstruction[END_REF]). In the case of taxa with a distribution area strongly modified by human activity (i. e., Microtus cabrerae and Testudo (Chersine) hermanni), they are not considered in the analysis [START_REF] Fernández-García | Paleoenvironmental context of Neanderthal occupations in northeastern Iberia: The small-mammal assemblage from Abric Romaní (Capellades, Barcelona, Spain)[END_REF]. Another problem related to this method is the possible absence of current biological communities analogous to the fossil one [START_REF] Birks | Strengths and weaknesses of quantitative climate reconstructions based on Late-Quaternary[END_REF]. [START_REF] Guiot | Transfer functions: methods for quantitative paleoceanography based on microfossils[END_REF] proposed the use of the most similar assemblage as a possible solution to this trouble. Another assumption when applying this method is that the current distribution of species are exclusively determined by climatic parameters, omitting other factors as interspecific interactions [START_REF] Macarthur | Geographical Ecology e Patterns in the Distribution of Species[END_REF][START_REF] Chesson | General theory of competitive coexistence in spatially-varying environments[END_REF][START_REF] Chave | Comparing classical community models: theorical consequences for patterns of diversity[END_REF] and historical factors, i. e. geographical barriers (Morales Martín and Lizana Aria, 2011). Thus, the current distribution area of the species rarely coincides with its potential distribution area (Morales Martín and Lizana Aria, 2011). One of the requirements for the application of MER method is that the current distribution of the defined species may be well known. In general, it can be considered that the degree of knowledge of present distribution area of vertebrates in Spain is high, due to the existence of numerous atlases of different geographical levels and several citizen science projects, focused mainly in herpetofauna (AHE, 2021) and birds (SEO/Birdlife, 2021). Unfortunately, the databases of distribution area of species (i. e. national atlases of herpetofauna) are based on unnatural units, 10 × 10 km UTM square grids [START_REF] Pleguezuelos | Atlas y Libro Rojo de Los Anfibios y Reptiles de España, 2a impresión[END_REF]Loureiro et al. 2018;[START_REF] Ahe | SIARE (Servidor de Informacion de Anfibios y Reptiles de España). Asociación Herpetológica Española[END_REF]. This artefact strongly affects the validity of the palaeoclimatic reconstruction [START_REF] Martínez-Solano | Anfibios y Reptiles del Pleistoceno medio de Ambrona[END_REF]Fagoaga et al. 2019a). The surface occupied by each unit (100 km 2 ), could include areas with a strongly topographical heterogeneity [START_REF] Martínez-Solano | Anfibios y Reptiles del Pleistoceno medio de Ambrona[END_REF]Fagoaga et al. 2019a). In topographically diverse regions such as Iberian Peninsula [START_REF] Tullot | Climatología de España y Portugal[END_REF], climatic conditions vary significantly between geographically proximate locations. Moreover, species are not present anywhere within the 100 km 2 of the UTM square because not all of the territory responds to the ecological needs of these (Fagoaga et al. 2019a). In this sense, the use of the territory by a species depends on the environmental context and by the interactions established among co-ocurring taxa. As a result, we could be introducing bias into our palaeoclimatic reconstruction by including areas (and its climatic values) where some species could not be present (Fagoaga et al. 2019a). To improve the accuracy of the palaeoclimatic reconstruction derived from MER method, Fagoaga et al. (2019a) define the UDA-ODA discrimination technique. Basically, this new method is based in the application of an ecological criterion for the discrimination of Occupation Distribution Areas (ODA), where in theory the species is present, from those where its presence is highly doubtful, the Uncertain Distribution Area (UDA) (Figure 2). Although Fagoaga et al. (2019a) consider it a method totally distinct to MER method, actually both are a different approach of the same strategy: the search of the common distribution area of a given fossil biological assemblage. As [START_REF] Kothari | Research methodology: methods and techniques[END_REF] denotes methods are more general, given the theorical framework (search of common distribution area, that is MER) for the development of different behaviours and instruments to perform research (application of a ecological criterion to record the climatic data). Despite the fact that this discussion may seem trivial, in reality the definition and distinction of the methods and techniques developed is a key tool for the correct development of scientific knowledge. Failure to do this step correctly could lead to robust methods and techniques being discarded due to confusion generated by the incorrect use of terminology [START_REF] Lyman | The mutual climatic range technique is (usually) not the area of sympatry technique when reconstructing paleoenvironments based on faunal remains[END_REF]. It has long recognised that the evolution of the climate has a crucial impact in the natural history of humans and, for that reason, palaeoclimatic reconstructions feature prominently in palaeoanthropological debates [START_REF] Haywood | What can Palaeoclimate Modelling do for you?[END_REF]. In this sense, the disappearance process of the Neanderthals has been focused from this topic. This event took place during Marine Isotope Stage (MIS) 3 (ca. 30-60 ka in accordance with [START_REF] Railsback | An optimized scheme of lettered marine isotope substages for the last 1.0 million years, and the climatostratigraphic nature of isotope stages and substages[END_REF]) (e.g. [START_REF] Malkmus | The significance of stratigraphic discontinuities in Iberian Middle-to-Upper Palaeolithic transitional sites[END_REF]. This was an unstable climatic period in the Late Pleistocene that was characterised by alternating warm phases with expanding forests and cold phases when semi-arid areas developed (e.g. [START_REF] Fletcher | Orbital and sub-orbital scale climate impacts on vegetation of the Western Mediterranean basin over the last 48 000 years[END_REF]. The reason/s behind the demise of the Neanderthals is an unresolved debate in the scientific community. Although numerous hypotheses that have been proposed to explain this event, these can be grouped in three categories [START_REF] Vaesen | An emerging consensus in palaeoanthropology: demography was the main factor responsible for the disappearance of Neanderthals[END_REF]).

The first one is related with the migration of anatomically modern humans (AMH) in Europe, which competed with the Neanderthals for the resources and, finally, the last were replaced by the first [START_REF] Mellars | Neanderthals and the modern human colonization of Europe[END_REF]). However, due to the scarcity of human remains in Late Pleistocene sites of the Iberian Peninsula [START_REF] Strauss | The upper paleolithic of Iberia[END_REF], direct contact between both humans groups is hard to demonstrate [START_REF] Vaquero | The Neandertal-Modern Human meeting in Iberia: A critical view of the cultural, geographical and chronological data[END_REF][START_REF] Malkmus | The significance of stratigraphic discontinuities in Iberian Middle-to-Upper Palaeolithic transitional sites[END_REF]). Thus, this contact has been mainly based only on lithic tools. Nevertheless, whereas the Mousterian is well assumed that have been manufactured by Neanderthals [START_REF] Vaquero | The Neandertal-Modern Human meeting in Iberia: A critical view of the cultural, geographical and chronological data[END_REF], the attribution of Aurignacian tools to Homo sapiens? is highly controversial [START_REF] Strauss | The upper paleolithic of Iberia[END_REF]. Moreover, there are several problems related to the proposed dates for the contact between both human groups in several Iberian sites. As [START_REF] Wood | Radiocarbon datingcasts doubt on the late chronology of the Middle to Upper Palaeolithic transition in southern Iberia[END_REF] pointed out, the studied period is close to the practical limit for radiocarbon dating; postdepositional disturbance processes on dated elements and archaeological evidences cannot be discarded; diagnostic elements in the lithic assemblage are lacking; and finally, some proposed radiocarbon dates are inaccurate due to the use of inadequate pretreatment protocols. The second group of hypotheses are related to the apparent small size of Neanderthal populations and the limited interconnectedness between them [START_REF] Vaesen | An emerging consensus in palaeoanthropology: demography was the main factor responsible for the disappearance of Neanderthals[END_REF].

These particularities would have made them highly susceptible to inbreeding, allee effects and stochastic fluctuations [START_REF] Finlayson | Neanderthals and Modern Humans: An Ecological and Evolutionary Perspective[END_REF][START_REF] Vaesen | Inbreeding, Allee effects and stochasticity might be sufficient to account for Neanderthal extinction[END_REF]. Finally, the third group points out that the demise of Neanderthals was related with environmental factors, i. e. climate change [START_REF] Bradtmöller | The repeated replacement model-Rapid climate change and population dynamics in late Pleistocene Europe[END_REF]. During its existence, Neanderthals were highly influenced by climate, reaching its northernmost limit during warm episodes [START_REF] Stewart | The ecology and adaptation of Neanderthals during the nonanalogue environment of Oxygen Isotope Stage 3[END_REF]). Although at the beginning of the MIS 3 Neanderthals were widespread around Europe, their distribution range was gradually shrinking towards the south [START_REF] Stewart | The evolutionary consequence of the individualistic response to climate change[END_REF]. The present consensus establishes that the final demise of Neanderthals took place at Iberian Peninsula probably during Heinrich Event (HE) 4 (ca. 40.2-38.3 ka) [START_REF] Bradtmöller | The repeated replacement model-Rapid climate change and population dynamics in late Pleistocene Europe[END_REF] or just before its onset (ca. 40.2 ka) [START_REF] Wood | Radiocarbon datingcasts doubt on the late chronology of the Middle to Upper Palaeolithic transition in southern Iberia[END_REF][START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF][START_REF] Wolf | Climate deteriorations and Neanderthal demise in interior Iberia[END_REF]. In Mediterranean coastal areas severe aridity episodes has been detected during this HE (Sepulchre et al. 2007); however, at least for the interior area of the Iberian Peninsula, the mentioned climate deterioration does not seem to have coincided with HE 4 [START_REF] Wolf | Climate deteriorations and Neanderthal demise in interior Iberia[END_REF].

The Central coastal region of the Spanish Mediterranean coast has yielded numerous Middle Palaeolithic sites [START_REF] Eixea | Neanderthal Spatial Patterns and Occupation Dynamics: A Focus on the Central Region in Mediterranean Iberia[END_REF]). Among them, El Salt site (Alcoi, Spain) is a key locality for studying the disappearance of Neanderthals in the region. Its high value lies in the fact that the archaeological sequence of El Salt records different occupation phases, in which a transition from recurrent to sporadic human occupation (and finally, an abandonment of the site) have been identified [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]. Moreover, El Salt yielded six Neanderthal teeth, possibly belonging to an individual from one of the last groups in the region [START_REF] Garralda | Neanderthals from El Salt (Alcoy, Spain) in the context of the latest Middle Palaeolithic populations from the southeast of the Iberian Peninsula[END_REF]. The vertebrate faunal assemblage recovered from the site allows studying and interpreting the climatic evolution at local level in the south-eastern Iberian Peninsula during the Middle Palaeolithic and the possible impact on the local palaeoecology and, therefore, on the human populations inhabiting the area. In this sense, the study of the small vertebrates assemblages from El Salt has been focused on this topic (Marquina-Blasco et al. 2017, 2021;[START_REF] Fagoaga | Palaeoecological implications of Neanderthal occupation at Unit Xb of El Salt (Alcoi, eastern Spain) during MIS 3 using small mammals proxy[END_REF]Fagoaga et al. , 2019a, b), b). Until now the majority of these works has been based on the application of MER method (Marquina-Blasco et al. 2017, 2021;[START_REF] Fagoaga | Palaeoecological implications of Neanderthal occupation at Unit Xb of El Salt (Alcoi, eastern Spain) during MIS 3 using small mammals proxy[END_REF]Fagoaga et al. , 2019b)), with its inherent limitations already discussed above. Later, Fagoaga et al. (2019a) developed and applied the UDA-ODA discrimination technique to the small mammal assemblages provided by Stratigraphical Unit (SU) Xb and V from El Salt site. Thus, the aim of this study is to reconstruct the environmental conditions prevailing in SU Xb and V from El Salt site, based on the application of this techniqueUDA-ODA discrimination technique on the amphibian and reptiles assemblages recovered from both SUs for the first time to this kind of fauna. Our results are discussed with previous works of palaeoclimatic reconstruction based on small vertebrates and other proxies from El Salt. In addition, we contextualize our results with the debate about the disappearance of Neanderthals, focusing on the ecological context in 179 which these events occurred.

GEOLOGICAL SETTING

The Middle Palaeolithic site of El Salt (Alcoi, Alicante) (716,673; 4,284,952; 30S) (Figure 3) rests against a 38 m-high Paleocene limestone wall at 680 m above sea level. The wall is the result of a trust fault of Eocene limestone over Paleocene conglomerates. At the upper part of the wall the course of the Barxell River was stopped by the presence of the limestone, creating a palaeolake that outflowed over the fault. As a result, a large travertinic building was created along more than 2.5 km in the foothills of the Serra de Mariola [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]. The sedimentary sequence of the site consists of thirteen lithostratigraphic units (Fumanal 1994) grouped into five segments, in basis of its macroscopic textural appearance and archaeological context (Galván et al 2014) (Figure 4).

From base to top:

 SU XIII: subtravertine platform of unknown thickness. Its top has been dated by U/Th as 81.5 ± 2.7 ka and 80.1 ± 4 ka (MIS 5a-ca. 82-71 ka) [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]). This SU is archaeological sterile.

 SU XII to IX: these units consist of 1.5 m of horizontally bedded fine sand, with several large blocks at their base and related to a first episode of roof collapse [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]. This part of the sequence has been dated, using thermoluminescence (TL), as 60.7 ± 8.9 ka (SU XII) and 52.3 ± 4.6 ka (SU X) [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF], placing the sequence at the beginning of MIS 3, before event HE 5 [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]). These SUs contain the highest concentration of archaeological remains and combustion features within the entire sequence.

 SU VIII to V: in this sequence a gradually decrease of human occupation evidences is recorded that ends quite spatially reduced. SU VI is covered by a significant accumulation of large blocks, produced by the collapse of the roof of the travertine structure. Six Neanderthal teeth attributed to a juvenile or young adult were recovered from the base of SU V [START_REF] Garralda | Neanderthals from El Salt (Alcoy, Spain) in the context of the latest Middle Palaeolithic populations from the southeast of the Iberian Peninsula[END_REF]). These remains may represent one of the last occurrences of Neanderthals in the region [START_REF] Garralda | Neanderthals from El Salt (Alcoy, Spain) in the context of the latest Middle Palaeolithic populations from the southeast of the Iberian Peninsula[END_REF]. The top of SU VI has been dated by TL as between 52.3 ± 4.6 and 47.2 ± 4.4 ka, whereas the base of SU V has been dated by optically stimulated luminescence (OSL) as 45.2 ± 3.4 ka [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]. The middle part of SU V has been dated by OSL as 44. 7 ± 3.2 ka, [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]. The upper part of SU V consists of a 50 cm-thick layer, truncated by a Holocene erosive episode. It is constituted by massive sandy silt with heterogeneous gravel in the top 20 cm, from which two small flint blades, a few undifferentiated flakes, and a small combustion structure have been recovered [START_REF] Garralda | Neanderthals from El Salt (Alcoy, Spain) in the context of the latest Middle Palaeolithic populations from the southeast of the Iberian Peninsula[END_REF].

 SU IV to I: gravelly deposit with a 1.3 m thick stratigraphic segment constituted by a stratified succession of channels filled with different beds of gravelly sands with cobbles, separated by sharp erosional contacts.

Neolithic pottery mixed with late Upper Palaeolithic, Epipalaeolithic and Mesolithic lithic remains indicates that this deposit is of Holocene age [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]. This together with the biochronological contradiction of the recovered small vertebrate fauna (presence of Microtus arvalis, extirpated in the region at the end of the Late Pleistocene) denotes reworked episode/s of this deposit [START_REF] Fagoaga | Small vertebrates from a Holocene gravelly deposit at El Salt (Alcoi, Alicante)[END_REF].

MATERIAL, METHODS, AND ABBREVIATIONS

To conduct the palaeoclimatic reconstruction, we apply the UDA-ODA discrimination technique (Fagoaga et al. 2019a) on the amphibians and reptiles assemblage from SU Xb (Xb-11 S3) and two different segments of the SU V: V-24 (surfaces (S ) 7, 8, and9), andV-25 (Table 1). The faunal list of the analyzed assemblages has been taken from Marquina-Blasco et al. (2017, 2021). This method is based on the application of an ecological criterion to distinguish those areas that are ecologically habitable for each species (ODA) from those that, in principle, lack the necessary requirements for use by the taxon (UDA). After this, the method searches the modern biogeographic co-occurrence of the ODAs of species described in a palaeontological or archaeological site. As discrimination factor we have use elevation for each species. The choice of this criterion was based on several points: (i) ease of implementing this information in Geographic Information Systems (GIS); (ii) existence at Spanish level, and to a lesser extent in Portugal, of distribution atlases with altitudinal distribution information on herpetofauna at various administrative levels: national (i.e., [START_REF] Pleguezuelos | Atlas y Libro Rojo de Los Anfibios y Reptiles de España, 2a impresión[END_REF][START_REF] Loureiro | Atlas Dos Anfíbios e Répteis de Portugal, 1st Editio. Instituto da Conservação da Natureza e da Biodiversidade[END_REF]), regional (i.e., Bea 1985;[START_REF] Llorente | Atlas dels amfibis i rèptils de Catalunya i Andorra, 1a Edició[END_REF]), provincial (i.e., Pérez-Mellado 1983;[START_REF] Barberá | Atlas provisional de distribución de los anfibios y reptiles de la provincia de Cuenca (Castilla-La Mancha, España)[END_REF], protected areas (i.e., Santos et al. 2005;[START_REF] Domínguez | Atlas de los vertebrados terrestres reproductores en el Parque Natural Baixa Limia-Serra do Xurés y ZEPVN-LIC Baixa Limia[END_REF], and even particular mountainous systems [START_REF] Rica | Atlas Herpetológico Del Pirineo[END_REF][START_REF] Lizana | Distribución altitudinal de la Herpetofauna en el Macizo Central de la Sierra de Gredos[END_REF]); (iii) altitudinal distribution of Iberian reptile and amphibian species is relatively well known; (iv) in the case of Iberian reptiles, the maximum altitude reached by species is a better discriminant than mean altitude when performing a biogeographical analysis (Saint Girons 1982); and (v) altitude is a very important factor in explaining the distribution of amphibians and, especially, reptiles due to its clear effect on temperature and precipitation [START_REF] Soares | Environmental correlates for species richness among amphibians and reptiles in a climate transition area[END_REF]. We have considered here the entire Iberian Peninsula, an area with natural geographical limits. The choice of this analytical unit is also supported by the fact that some species that could potentially appear in the site are Iberian endemisms (e.g. Chalcides bedriagai). The biogeographic cartography of amphibians and reptiles for Spain is provided by the Servidor de Información de Anfibios y Reptiles de España (SIARE) (AHE 2021); for Portugal, it is provided by [START_REF] Loureiro | Atlas Dos Anfíbios e Répteis de Portugal, 1st Editio. Instituto da Conservação da Natureza e da Biodiversidade[END_REF]. Using ArcGis 9.1®, the climatic parameters are estimated by overlapping the co-occurrence areas and the current climate layers with a 30-arcseconds resolution grid from WorldClim 1.4 [START_REF] Hijmans | Very high resolution interpolated climate surfaces for global land areas[END_REF].

Table 1. Faunal list from Stratigraphic

Both sets of data (co-occurrence areas and climate layers) are represented in the same spatial reference system (EPSG 4326, WGS 84 UTM datum coordinate projection system). The bioclimatic parameters extracted from the cartography supplied by [START_REF] Hijmans | Very high resolution interpolated climate surfaces for global land areas[END_REF]

RESULTS

Altitudinal range of the target species

A total of 89 works have been evaluated for the determination of the altitudinal range in the mountain range of the herpetological species included in the assemblage of SU Xb and V from El Salt site. The detailed list of these references, which include papers, books, atlases, field guides, and technical reports, are included in the Supplementary Material 1. The obtained results show an increase in the maximum height from North to the South (Table 2), except for Alytes obstetricans, which reaches higher altitude in the Pyrenees than other southern ranges, i.e. Iberian and Central Range (Figure 5). Table 2 summarizes the maximum altitude reached by each species in every mountain system in the Iberian Peninsula, the detailed information about it is included in the Supplementary Material 2.

Method comparison per variable and species

The application of the T-test for independent samples of each climatic parameters (MAT, MinTC, MaxTW, and MAP)

in each species determined in the herpetofaunal assemblage from El Salt, shows significant differences between ODA and UDA (p< 0.01) (Table 3). ODA shows higher mean values for those climatic parameters related with temperatures (MAT, MinTC, and MaxTW) than UDA; regarding to MAP, UDA had higher mean values than ODA (Table 3).

Method comparison per variable and species

As the above case, the T-test for independent samples for all assemblages and bioclimatic parameters analysed shows significant differences within ODA and UDA (p< 0.01) (Tabla 4; Figure 6). The first shows higher values for MAT, MaxTW, and MinTC than the second. For its part, UDA shows higher values for MAP than ODA (Tabla 4). The biggest differences between ODA and UDA have been recorded in Xb-11 S3 for MAT, MaxTW, and MinTC (+6.85 ºC, +6.64 ºC, and +6.47 ºC, respectively) and in V-25 for MAP (-269.85 mm). In contrast, the smallest differences are obtained in V-24 S9 and V-24 S7 for all bioclimatic parameters (MAT: +5.55 ºC; MaxTW: +4.75 ºC; MinTC: +5.37 ºC, and, MAP: -180.92 mm). In general, the Standard Deviation (σ) is smaller in the results obtained using UDA distribution than those obtained by ODA. However, there are some cases where the opposite situation is observed (MAT in Xb-11 S3 and all values for MAP from SU V). As the above case, Coefficient of Variation (CV) is also higher in ODA than UDA, except for the results obtained for MAT in Xb-S3 11 and V-25 (Tabla 4).

MER vs ODA

In general, the results obtained between two common distribution area, those provided by atlases, MER and ODA, are similar. For these parameters related with temperature, MAT, MaxTW, and MinTC, are higher in ODA than in MER (Tabla 4). However, the studied assemblage from V-24 S7, V-24 S9, and V-25 Have provided higher values for MaxTW in MER than ODA.

Regarding to MAP, the results based in MER are higher than ODA in Xb-11 S3 and V-24 S8. The opposite is true for the other samples, i.e. MAP values are higher in ODA than in MER (Tabla 4).

DISCUSSION

Altitudinal range of the target species

All the species studied show euryhypsas behavior, being distributed from sea level to high altitudes in most of the Iberian mountain systems, in agreement with previous studies on this subject (i.e. [START_REF] Pleguezuelos | Distribución altitudinal de la herpetofauna ibérica[END_REF].

In this sense, Iberian species of herpetofauna with a narrow altitudinal distribution range are scarce [START_REF] Pleguezuelos | Distribución altitudinal de la herpetofauna ibérica[END_REF], which is related with the wide distribution and a high ecological tolerance of these species in the region [START_REF] Sillero | Biogeographical patterns derived from remote sensing variables: the amphibians and reptiles of the Iberian Peninsula[END_REF]). In general, amphibians reach higher maximum altitudes than reptile species (see Figure 5), which is mainly related with the different evolution of temperatures and moisture against the elevation [START_REF] Heatwole | A review of structuring in herpetofaunal assemblages[END_REF]. Thus, temperature decreases linearly with the altitude (approximately 0.50 ºC/100 m); whereas the rainfall is positively related with the altitude (Font [START_REF] Tullot | Climatología de España y Portugal[END_REF]. Nevertheless, this explanation is simplistic since there are other factors that also influence this distribution, such as the decrease of the environmental heterogeneity and vegetation cover [START_REF] Heatwole | A review of structuring in herpetofaunal assemblages[END_REF], and lower presence of potential preys [START_REF] Lizana | Analysis of the structure of an amphibian community in the Central System of Spain[END_REF]), among others. Thus, it can be seen that the difference between the altitude used for the identification of ODAs, based on the consultation of the available scientific literature, and that obtained without these discrimination criterion (i.e., UTM grid of 10 × 10 km) is, in general, greater in reptiles than in amphibians (Table 2). In this sense, Natrix maura shows the major difference in the northernmost mountain ranges (Galician Massif, -841 m; Cantabrian Range, -1,144 m; Pyrenees, -1,516 m; and Iberian Range, -625 m). The altitudinal distribution of N. maura seems to be limited by the presence of water bodies in the environment and for the low temperatures reached in the higher elevations [START_REF] Santos | Culebra viperina-Natrix maura[END_REF]. Moreover, in the areas where N. maura cohabited with the congeneric Natrix astreptophora, as in the north of Spain, the former trends to inhabit lower altitudes than the second [START_REF] Malkmus | The significance of stratigraphic discontinuities in Iberian Middle-to-Upper Palaeolithic transitional sites[END_REF]); however, both species avoid direct competition by different use of trophic resources and ecological segregation [START_REF] Galán | Segregación ecológica en una comunidad de ofidios[END_REF]). In the rest of the systems, the species showing the greatest difference are also reptiles: Vipera latastei in Montes de Toledo and Sierra Morena ranges from -579 and -230 m, respectively, Blanus rufus in Central Range -686 m, and Chalcides bedriagai in the Betic Range -1,522 m. As the case of N. maura, the distribution of V. latastei in the Northern Iberian Peninsula is limited by the presence of parapatric viper species, Vipera seoanei and Vipera aspis, which reached higher altitudes than the former [START_REF] Duguy | La répartition des vipères dans les Pyrénées et les régions voisines du nord de l'Espagne[END_REF][START_REF] Girons | Biogéographie et évolution des vipères européennes[END_REF]Brito and Crespo 2007), and for climatic parameters [START_REF] Martínez-Freiría | GIS-based niche models identify environmental correlates sustaining a contact zone between three species of European vipers[END_REF]. Regarding to C.

bedriagai, the species does not seem to be limited in its altitudinal distribution by winter temperatures, contrary to strictly thermophilic species. On the other hand, it seems to select positively those points with low precipitation during the hottest periods of the year and with abundant sun exposure [START_REF] Maluquer-Margalef | Aportacions sobre la distribució altitudinal de Chalcides bedriagai (Boscá, 1880) al massís de Penyagolosa (Castelló) i el poblament herpetològic del vessant nord del massís[END_REF]). However, given the cryptic ecology of both C. bedriagai and both species of the genus Blanus (Blanus rufus and Blanus cinereus) the range of these species is far from be well known in many areas of the Iberian Peninsula [START_REF] Pollo | Chalcides bedriagai (Boscá, 1880. Eslizón ibérico[END_REF][START_REF] López | Blanus cinereus (Vandelli, 1797). Culebrilla ciega[END_REF].

Due to this reduction in the altitudinal limit applied to all species, there is also a reduction in the total occupied area of the ODAs of each species compared to the distribution provided by the atlases. Again, reptile species present a greater reduction area than the amphibians, especially on ophidians (Table 5; Figure 7).

Discussion of the methods per variable and species

The reduction in the area occupied by each species is reflected in a modification in the evaluated bioclimatic parameters. Regarding to temperatures, ODA yielded higher mean values for temperatures and lower ones for rainfall than UDA for all species (Table 3). As Fagoaga et al. (2019a) pointed out, ODA which is actually more linked to the species, provide a more accurate distribution than atlases, which are based on a roughly estimation of the distribution area of the species [START_REF] Barbosa | New measures for assessing model equilibrium and prediction mismatch in species distribution models[END_REF]). As a result, UDA-ODA discrimination method provides more accurate bioclimatic values due to the implementation of an ecological discrimination criteria based, in this case, on the maximum altitude of each species. The implemented discrimination criteria, the maximum altitude per Iberian range, resulted in the elimination of the higher cotes of the respective mountains. As the temperatures decreases with the altitude, it is expected that the lower values were deleted in our estimations. Thus, an increase in these values is recorded (MAT, MaxTW, and MinTC). The obtained values with this methodology are incremented between +0.17 and 0.03 for MAT, 0.17 and 0.04 for MaxTW, and 0.15 and 0.03 for MinTC. In all these cases, Natrix maura shows the major reduction. This taxon shows the major differences between the maximum altitude recorded in the literature and the altitude provided in the atlases (Table 2). On this part, Bufo spinosus presents the minor difference in the three bioclimatic parameters, together with of Blanus cinereus s.l. in the case of MaxTW and Epidalea calamita for MinTC.

These three taxa are considered as the species with fewer differences in the recorded maximum altitude (Table 2) Regarding to rainfall, the results show a decrease in the obtained values by UDA-ODA discrimination method in all species compared to those provided by the application of MER method (Tabla 4). In general, precipitation increases with elevation (Daly et al. 1993 and reference therein). For this reason, the elimination of higher altitudes results in lower values for this parameter compared with the values obtained with the complete range in a determined grid. Thus, the range of values varies between -8.24 and -1.13 mm between MER and UDA techniques (Table 2). As the above cases, Natrix maura shows the highest reduction in MAP (-8.24 mm), followed by Chalcides bedriagai (-3.80 mm), and

Alytes obstetricans (-3.09 mm).

As well as herperofauna, small mammals from the same SUs of El Salt site, shows lower mean temperatures and higher rainfall in UDA results than ODA ones, except Microtus arvalis which behaves in the opposite way (Fagoaga et al. 2019a).

Additionally, as σ is lower in the obtained values in ecological criteria distribution area than those obtained by the distribution based on UTM 10 × 10 km grid, the first technique provides results statistically more robust.

Discussion of the methods per variable and assemblage

In all associations, ODA yielded higher mean values for temperatures and lower ones for rainfall than UDA (Tabla 4).

Again, these differences seem to be related with the delete of the highest altitudes in the delimitation of ODAs against UDAs. As mentioned above, ODA provides more accurate climatic and distributional information than those provided by the intersection of the distribution area provided by atlases (Fagoaga et al. 2019a). With the use of the latter, it is assumed that a determinate species has the same possibilities to inhabit anywhere within the UTM 10 × 10 km square grid (100 km 2 ). Thus, after applying an ecological discrimination criterion, as highest range reached by each species in the different Iberian ranges, we have introduced results theoretically more representative of the evaluated assemblage than the use of the whole area of the grid. As a result, the palaeoclimatic reconstructions are more accurate than those obtained in similar methodologies as MER (Fagoaga et al. 2019a). Furthermore, statistically the ODA values appear more reliable than those obtained by MER. In this sense, the σ is smaller in all cases for the bioclimatic parameters related with temperature, except for the case of MaxTW from V-24 S8. Regarding to MAP, the σ is smaller for ODA in the samples of Xb-11 S3 and V-24 S8 (Tabla 4). On the other hand, the σ in the means obtained by ODA is higher than in MER for the rest of the associations studied. In regard to CV, which relate the extent of variability in relation to the mean, its values are lower in ODA than in MER, except for MAP in Xb-11 S3 and V-24 S8 (Tabla 4). Thus, on this basis, the results obtained using MER show a higher relative variability than ODA. The obtained results for each MAT and MinTC absolute values based on UDA-ODA discrimination technique are slightly higher than those obtained with the MER method ( Figure 8). It is explained by the elimination of higher altitudes, in which are recorded the lower values of that parameters. Unlike with climatic results derived from each of the species, those obtained from association are disparate, as they do not behave equally between associations and parameters. The new palaeoclimatic reconstruction yields higher values of MaxTW in Xb-11 S3 and V-24 S8 than the calculated by MER; whereas this parameter is slightly lower in V-24 S9, V-24 S7, and V-25. As in the latter case, MAP values also present disparate results, while V-24 S7, V-24 S9 and V-25 values are higher using ODA than those based on atlas distribution, in Xb-11 S3 and V-24 S8 they are lower ( Figure 8). These results are difficult to interpret and may be due to the effect of the influence of orography on small/medium scale conditions. In the Iberian Peninsula most of the ranges are distributed from west to east (i. e., Pyrenees, Cantabrian Range, and Central Range) (Font Tullot 2000; Pascual and Sanz 2017); as a consequence of this general orientation, there is a particularly strong interaction with the atmospheric flows with northern and southern components [START_REF] Pascual | Aproximación a la Meteorología de Montaña[END_REF]. Moreover, the orientation of the Earth relative to the sun causes a latitudinal gradient in solar radiation [START_REF] Dubayah | Modeling a solar radiation topoclimatology for the Rio Grande River Basin[END_REF]). In the case of the Northern Hemisphere, the sun is slightly oriented to the south. As a result, there are strong local gradients in solar radiation, which is not only influenced by the slope orientation, but also on elevation, slope angle, and shadowing [START_REF] Dubayah | Modeling a solar radiation topoclimatology for the Rio Grande River Basin[END_REF]. As a result, the southern slope tends to be drier and hotter than the northern slope [START_REF] Dubayah | Modeling a solar radiation topoclimatology for the Rio Grande River Basin[END_REF][START_REF] Kutiel | Spatial distribution of soil surface coverage on north and south facing hill slopes along a Mediterranean to extreme arid climatic gradient[END_REF][START_REF] Begum | Influence of slope aspect on soil physico-chemical and biological properties in the mid hills of central Nepal[END_REF]. In Mediterranean areas, the southern slopes are dominated by stones and bare soil patches. In contrast, the slopes oriented to the north show dominance by biological components [START_REF] Kutiel | Spatial distribution of soil surface coverage on north and south facing hill slopes along a Mediterranean to extreme arid climatic gradient[END_REF]. This influences both directly and indirectly the distribution of plant and animal species, composition of biological communities, biological productivity, species richness, structures and densities of plant communities [START_REF] Dubayah | Modeling a solar radiation topoclimatology for the Rio Grande River Basin[END_REF]González Hidalgo et al. 1998;[START_REF] Gong | Slope aspect has effects on productivity and species composition of hilly grassland in the Xilin River Basin, Inner Mongolia, China[END_REF][START_REF] Shepard | Lineage diversification and historical demography of a sky island salamander, Plethodon auachitae, from the Interior Highlands[END_REF]Foord et al. 2014). In this sense, the climatic gradient between both slopes plays a crucial role in the distribution of the amphibians and reptiles, especially in the areas bordering the species' distribution areas.

For example, some amphibian species in arid areas inhabits northern slopes, as the salamander Plethodon auachitae in the Ouachita Mountains, western Arkansas and southeastern Oklahoma (USA) [START_REF] Shepard | Lineage diversification and historical demography of a sky island salamander, Plethodon auachitae, from the Interior Highlands[END_REF].

In Galicia, (northwestern Spain) Mediterranean species of lacertids, i.e. Podarcis bocagei and Podarcis guadarramae, seems to positively select southern-oriented slopes; whereas lizards with Atlantic ecological preferences, as Zootoca vivipara or Iberolacerta monticola, use all slopes indifferently (Bas López 1986). A similar case is the southern populations of Coronella austriaca in the Iberian Peninsula, which seem to select positively northern slopes (but not exclusively), where conditions are cooler and more humid than in other parts of the mountain range (Martínez del [START_REF] Del Mármol | Récord altitudinal de Coronella girondica en Europa, y otro caso de posible sintopía con Coronella austriaca en Sierra Nevada (Granada, España)[END_REF]. Considering these differences in temperatures and humidity, the probabilities of founding amphibians in northern slopes are higher than on southern ones, whereas the opposite trend is observed on reptiles, at least for northern Spain [START_REF] Bea | Herpetofauna de Guipúzcoa: Estudio Faunístico y Relaciones con la Climatología[END_REF]. This gradient is also recorded in our results. In fact, in those assemblages were the values of MaxTW and MAP are higher based on UDA-ODA discrimination technique than MER method there are a major reduction of the area occupied by southern slopes than northern ones (Table 6). On the contrary, the reduction area on Xb-11 S3 and V-24 S8, in which both MaxTW and MAP are lower in MER than in ODA, has been focused on northern slopes than southern ones (Table 6). Consequently, it is reduced the theorically highest values of rainfall and the lowest values of MaxTW. 329,978,118.96 374,108,287.66 ODA 318,873,133.48 363,163,069.33 The palaeoclimatic reconstruction seems to draw a scenario of an alternation of moments with higher temperature (Xb-11 S3, V-24 S8, and V-25) with others of lower temperatures (V-24 S9 and V-24 S8). As show in the Figure 8, the palaeoclimatic reconstruction based on MER method the samples with higher MAT values are coincident with the higher ones of MAP (Xb-11 S3, V-24 S8, and V-25) (Marquina-Blasco et al. 2021a). Roughly, there seems to be an alternation between "warm and wet" and "cooler and drier" moments. However, palaeoclimatic reconstruction based on ODA draws a slightly different scenario. In this case, it seems to indicate that "warm and dry" phases alternated with "cold and wet" ones. Moreover, the variations of the values between samples are higher in MER than in ODA. This latter observation is related with the elimination of more extreme values provided in MER, but not in ODA.

Herpetofauna vs small mammals and other proxies

The small mammal associations of the same SUs studied yielded the same pattern as herpetofauna based on UDA-ODA discrimination technique compared with MER method. In all the assemblages MAT, MaxTW, and MinTC are lower in ODA than MER, whereas MAP showed higher values in ODA than MER (Fagoaga et al. 2019a). However, our results

show higher absolute values than those provided by Fagoaga et al. (2019a) (Figure 9). As Marquina-Blasco et al. (2021) pointed out, these differences are related to the resulted current mutual distribution obtained in both methods, MER [START_REF] Fagoaga | Palaeoecological implications of Neanderthal occupation at Unit Xb of El Salt (Alcoi, eastern Spain) during MIS 3 using small mammals proxy[END_REF](Fagoaga et al. , 2019b) ) and UDA-ODA discrimination method (Fagoaga et al. 2019a) between both groups. The covered area of these distributions in the case of small mammals is more geographical located to the north and northwest of the Iberian Peninsula, whereas in the case of herpetofauna, this area is mainly formed by two distinct zones: one in the western Iberia and another in the east of Spain (Marquina-Blasco et al. 2017, 2021a). In general, Iberian species of reptiles and amphibians are well distributed along the peninsula, with few examples of taxa with limited distribution [START_REF] Pleguezuelos | Atlas y Libro Rojo de Los Anfibios y Reptiles de España, 2a impresión[END_REF][START_REF] Sillero | Biogeographical patterns derived from remote sensing variables: the amphibians and reptiles of the Iberian Peninsula[END_REF][START_REF] Ahe | SIARE (Servidor de Informacion de Anfibios y Reptiles de España). Asociación Herpetológica Española[END_REF]. As far as we know, the altitudinal distribution of Iberian reptiles and amphibians is a more studied issue than the regarded to small mammals. The palaeoclimatic reconstruction based on small mammals points to an evolution towards aridification of the region after the application of both methods, MER and UDA-ODA (Fagoaga et al. 2019a, b). In our case, the results based on reptiles and amphibians assemblages are coincident in the sense of lower rainfall in the modern SU than in the older ones, also in the both evaluated methods, MER (Marquina-Blasco et al. 2017, 2021a) and UDA-ODA (this work).

However, in the case of small mammals this parameter descends continuously from Xb-11 S3 to V-25 (Fagoaga et al. 2019a, b), whereas our results show a more erratic evolution, with an apparent decline in the MAP value between V-24 S7 to V-25. In contrast, in the MAT and MaxTW parameters, the reconstruction based on small mammals shows a gradual increase in values from the oldest (Xb) and modern (V) SUs. Regarding MinTC, these results indicate certain stability in this parameter. Overall, our results show a more erratic evolution, showing some instability in the parameters, interspersing moments with higher values (Xb-11 S3, V-24 S8 and V-25), with lower ones (V-24 S9 and V-24 S8). The above mentioned progression from older SU (Xb) more humid than modern ones (V) is also denote by numerous proxies from El Salt site. In this sense, the change in the dynamic of sedimentation, from one mainly based on anthropogenic and geogenic deposition to a sporadic eolian sedimentation, is related with colder climatic conditions (Gómez de la [START_REF] De La Rúa | Una visión geoarqueológica general del yacimiento musteriense de El Salt (Alcoy, Alicante) a partir de la micromorfología[END_REF][START_REF] Malkmus | The significance of stratigraphic discontinuities in Iberian Middle-to-Upper Palaeolithic transitional sites[END_REF]. Anthracological results also point to an aridification trend giving the increment of Juniperus sp. and Buxus sempervirens, as well as the reduction and/or absence of the hygrophilous, heliophilous taxa and pine trees from SU VIII to V (Vidal-Matutano, 2016). Although, the study of the palinological samples from El Salt site is still preliminary due to the scarce remains recovered and the existence of important palinological hiatus (i.e., SUs IX, X, and Xi are sterile), certain observations can be made about possible trends that reveal gradual decrease in temperatures and humidity (Dupré, 1992). Moreover, analyses of n-alkane chain show a dominance of herbaceous plants in a dry or semi-dry climatic context in the middle of the SU V [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF].

Implications for the last Neanderthals from El Salt

The human use of El Salt site shows clearly two major phases. The first, defined by the interval represented by SU XII to IX, is characterized by the presence of high concentration of human activity (archaeological remains, combustion residues, and abundant faunal remains associated with lithic tools) of recurrent short-term and seasonal human occupation events [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]Machado and Pérez 2016;[START_REF] Leierer | Insights into the timing, intensity and natural setting of Neanderthal occupation from the geoarchaeological study of combustion structures: a micromorphological and biomarker investigation of El Salt, unit Xb, Alcoy, Spain[END_REF]. The studies of palaeoclimatic and palaeonvironmental reconstruction focused on SU Xb (52.3 ± 4.6 ka) drawn humid conditions with dominant forest formations [START_REF] Marquina | Amphibians and squamate reptiles from the stratigraphic unit Xb of El Salt (Middle Palaeolithic; Alcoy, Spain): palaeoenvironmental and palaeoclimatic implications[END_REF][START_REF] Fagoaga | Palaeoecological implications of Neanderthal occupation at Unit Xb of El Salt (Alcoi, eastern Spain) during MIS 3 using small mammals proxy[END_REF]Fagoaga et al., , 2019b) in a supramediterranean sub-humid context [START_REF] Vidal-Matutano | Macrobotanical evidence (wood charcoal and seeds) from the Middle Palaeolithic site of El Salt, Eastern Iberia: palaeoenvironmental data and plant resources catchment areas[END_REF]. However, at the second phase (SU VIII to V), and in contrast to the former SUs, the human presence decreased until its apparent final abandonment of the site [START_REF] Malkmus | The significance of stratigraphic discontinuities in Iberian Middle-to-Upper Palaeolithic transitional sites[END_REF][START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]. After this archaeological hiatus, at the uppermost layer of SU V, two small flint blades, a few undifferentiated débitage flakes, and a small combustion feature were recovered [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]. A similar pattern has been observed in other

Iberian sites [START_REF] Malkmus | The significance of stratigraphic discontinuities in Iberian Middle-to-Upper Palaeolithic transitional sites[END_REF]. This process is coincident with colder and drier conditions. In this sense, the changes recorded in atmospheric circulation over the North Atlantic region during D/O stadials and HE has been related with an increment of the wind intensity in the Mediterranean region and, thus, higher aeolian sedimentation rates (Moreno et al. 2002). Probably related with it, at SU V it is recorded a depositional dynamic change, from a depositional processes dominated by gravitational component to another dominated by aeolian component and increase in the episodes of roof collapse (Gómez de la [START_REF] De La Rúa | Una visión geoarqueológica general del yacimiento musteriense de El Salt (Alcoy, Alicante) a partir de la micromorfología[END_REF]. Two dates are available for SU V. TL dating of the roof callopse, located at the base of this SU, and OSL dating obtained for its middle part, 45.2 ± 3.4 ka and 44.7 ± 3.2 respectively, indicates that the last Neanderthal occupations at El Salt took place prior to HE 4 [START_REF] Galván | New evidence of early Neanderthal disappearance in the Iberian Peninsula[END_REF]. A similar date for the abandonment of inner Iberian territories (42 ka) has been proposed by [START_REF] Wolf | Climate deteriorations and Neanderthal demise in interior Iberia[END_REF].

The new methodology applied to the herpetofauna assemblage from both SUs shows a similar evolution; that is, cooler conditions in SU V (44.7 ± 3.2 ka) than in SU Xb (52.3 ± 4.6 ka). The particular case of MAP deserves a special comment, since although it is slightly higher in the more modern SU than in the older one, the value obtained seems to indicate an evolution towards drier conditions. Thus the MAP value obtained in V-24 S7 is higher than in V-25.

The expansions/contractions of Neanderthal distribution areas were a constant in its natural history, which is related with numerous extirpations events and abandonments of sites [START_REF] Trinkaus | Neanderthal mortality patterns[END_REF]. In this way, the northernmost populations were reached during warm periods, whereas cold intervals supposed the retraction to southern localities [START_REF] Stewart | The ecology and adaptation of Neanderthals during the nonanalogue environment of Oxygen Isotope Stage 3[END_REF]. The survival of all of these climate changes denotes high ecological and behavioural plasticity for these humans [START_REF] Tattersall | Whe were the Neanderthals?[END_REF]. In fact, in some sites there is an apparent change in the technology, behavior and networks after the occurrence of cold phases (Delagnes and Rendu 2011). In the case of Eastern Iberia, Neanderthals occupations are related always with highly structures forest ecosystem [START_REF] Ochando | Iberian Neanderthals in forests and savannahs[END_REF]; where they would deploy their ambush-based hunting tactics (Stewart et al. 2019). Probably, this type of forest habitat could be a limiting factor for its distribution. Ecological models point out that 40 ky ago the potential habitat for Neanderthals was strongly reduced [START_REF] Melchionna | Fragmentation of Neanderthals' pre-extinction distribution by climate change[END_REF]. Although, as other extinction process, the demise of Neanderthals occurred in different chronologies at different European regions [START_REF] Higham | The timing and spatiotemporal patterning of Neanderthal disappearance[END_REF]). However, as [START_REF] Jennings | Southern Iberia as a refuge for the last Neanderthal populations[END_REF] suggested that rainfall, rather than temperatures, was a crucial parameter for Neanderthals populations. If the aridification trend observed by different climatic proxies at El Salt site was the main factor, or at least one with high influence, on the disappearance of Neanderthals in the region is a plausible explanation. However, more research is needed for clarify this question. In any case, as our results point out, in accordance with other biological proxies (charcoal, small mammals and, apparently, pollen), the disappearance of these humans at El Salt site, and by extension in the rest of the region, took place in a dry context.

CONCLUSIONS

The use of GIS software applied to MER method has allowed the development of new methodologies that apply techniques to improve the accuracy of palaeoclimatic reconstructions, such as UDA-ODA discrimination technique. In addition, it allows reproducible results to be obtained. In this sense, the use of the distribution area of species according to their ecological preferences (such as altitude range) as a discrimination factor provides a more accurate palaeoclimatic reconstruction due to its new biological point of view. Our results demonstrate that the application of the altitude range for each Iberian range preferably removes low values for temperature and rainfall, due to the evolution of these parameters with altitude (decrease in temperature with altitude and increase in precipitation). Moreover, for a statistical point of view, the results from the application of this method show in general slightly lower σ compared to those obtained by MER method (except for MAP, but not in V-24 S8). The UDA-ODA discrimination technique presents, in general, a lower CV in the mean of each bioclimatic parameter. Thus, this method of palaeontological reconstruction is more accurate, not only on a theoretical level in the sense of applying an ecological criterion that makes more sense of the distributions used, but also appears to be statistically more robust.

According to the palaeoclimatic reconstruction, climate was slightly warmer and wetter than today in the older SU (Xb, 52.3 ± 4.6 ka). In contrast, in SU V (44.7 ± 3.2 ka) the climate was cooler and more humid than the recorded currently at Alcoi. The absolute values of the different bioclimatic parameters are higher than those based on small mammals assemblages. These differences between the obtained values are related with the widely distribution range of the Iberian species of amphibians and reptiles. Regarding to small mammals, the species presents, in general, more limited distribution range. Moreover, the altitudinal distribution of small mammals' species seems to be less studied than in herpetofauna. For this reason, the ecological criteria for definition of ODA of these species had not defined for each Iberian mountain system. Thus, our results and those provided by small mammals' distribution are not comparable at all.

Although our results are, in general, coincident with other proxies studied at El Salt site, that is, an evolution towards drier and an apparent colder conditions from older SU (Xb) to modern ones (V), some differences are observed. In this sense, our results draw a more erratic evolution.

Regarding to the anthropic use of El Salt site, our results demonstrate that the abandonment process of the site took place in a context of a progressive aridification, as other proxies also point out. Whether there is a causal relationship between the two processes is a matter for future multidisciplinary work to discern.

Figure 1 .

 1 Figure 1. Schematic explanation of the Mutual Ecogeographic Range (MER) method, which is based in the detection of the current common distribution area of a determined fossil assemblage.

Figure 2 .

 2 Figure 2. Schematic explanation of the UDA-ODA discrimination technique, which is based in the application of an ecological criterion for the discrimination of the occupied areas (ODA) by a determined species from those of uncertain distribution (UDA), which does not accomplish with the ecological requisites of this species. After this discrimination, the method detect the current common ODA of a fossil assemblage.

Figure 3 .

 3 Figure 3. Geographic location of the El Salt site (black star) in the Iberian Peninsula.

Figure 4 .

 4 Figure 4. Lithostratigraphic column of El Salt showing the different Stratigraphic Units (SU) described by Fumanal (1994), lithology of each SU and its proposed datation (Galván et al., 2014). Modified from Garralda et al. (2014).

  Unit Xb (Marquina-Blasco et al. 2017) and V (Marquina-Blasco et al. 2021) from El Salt. 1: presence; 0: absence.

Table 2 .

 2 Maximum altitude reached by each species in the different mountain systems of the Iberian Peninsula for ODA (based on specialized literature) and for UTM grid (based on the calculated maximum value from 10 × 10 km UTM square grids distribution area), which are obtained from the elevation model provided by Hijmans et al. (2005). Δ: Differences between the altitudes used for the determination of ODA and those provided by atlases. Sources: Duguy et al. (1979); Falcón Martín (1982); Martínez Rica (1983); Pérez Mellado (1983); Bas López (1984); Bea (1985); Lizana et al. (1988); Galán and Fernández (1993); Meijide et al. (1994); Llorente et al. (1995); Pleguezuelos and Villafranca (1997); Barberá et al. (1999); Fernández-Cardenete et al. (2000); Serrano Ezaguerri et al. (2001); Bosch (2002); Morales et al. (2002); Ayllón et al. (2003); Vences et al. (2003); Malkmus (2004); Soares et al. (2005); Hernández-Sastre and Ayllón, 2007; García-Cardenete (2008); González-Fernández (2011); Domínguez et al. (2012); Puente Montiel (2013); Ferrer et al. (2018).

Figure 5 .

 5 Figure 5. Evolution of the maximum altitude of the herpetofauna species studied with respect to the latitudinal gradient of four Iberian mountain systems (from north to south: Pyrenees, Iberian System, Central System and Betic System).

Tabla 4 .

 4 Mean values, Standard Deviation (σ), and Coefficient of Variation (CV) of MAT (Mean Annual Temperature), MaxTW (maximum Temperature of the Warmest Month), MinTC (Minimum Temperature of the Coldest Month), and MAP (Mean Annual Precipitation), for each studied assemblage using MER, ODA, and UDA methods. T-test significance level is calculated between values of ODA and UDA. Δ: Differences between the obtained results based on MER and ODA.

Figure 6 .

 6 Figure 6. ODA (black areas) and UDA (white areas) of the common distribution areas for the different assemblages of fossil herpetofauna from El Salt site.

Figure 7 .

 7 Figure 7. ODA (grey area) and UDA (white area) of each species of the studied assemblages.

  , at least for Pyrenees and Cantabrian Range for Bufo spinosus (-554 and -744, respectively); Galician Massif, Central Range, and Montes de Toledo for Epidalea calamita (-51, 0, and -379 m, respectively), and Montes de Toledo for Blanus cinereus s.l. (-379 m).

Figure 8 .

 8 Figure 8. Comparison between the paleoclimatic reconstruction from Stratigraphic Units Xb and V of El Salt obtained by MER (black line) and ODA/UDA discrimination methodology (grey line). MAT (mean annual temperature, •C); MaxTW (maximum temperature of the warmest month, •C); MinTC (minimum temperature of the coldest month, •C); MAP (mean annual precipitation, mm).

Figure 9 .

 9 Figure 9. Evolution of the bioclimatic parameters after the application of the UDA-ODA discrimination technique to the fossil assemblages of herpetofauna and small mammals from Stratigraphic Units Xb and V of El Salt. MAT (mean annual temperature, •C); MaxTW (maximum temperature of the warmest month, •C); MinTC (minimum temperature of the coldest month, •C); MAP (mean annual precipitation, mm). Blak line, herpetofauna; grey line, small mammals.

Pyrenees Cantabrian Galician Iberian Central Montes de Toledo Sierra Morena Betic Alytes obstetricans

		Δ	-1024	-937	-51	-105	0	-379	-30	-661
	Blanus cinereus s.l. ODA	--	--	--	1100	1700	1200		2000
		UTM	--	--	--	1348	2386	1579		3322
		grid
		Δ	--	--	--	-248	-686	-379	-30	-1322
	Chalcides bedriagai ODA	--	--	1103	1720	1850	1200		1800
		UTM	--	--	1823	1937	2386	1579		3322
		grid
		Δ	--	--	-720	-217	-536	-379	-23	-1522
	Natrix maura	ODA	1500	1270	1210	1580	1800	1100		1950
		Atlases	3016	2414	2051	2205	2386	1579		3322
		Δ	-1516	-1144	-841	-625	-586	-479	-130	-1372
	Vipera latastei	ODA	1400	1200	1250	1700	2386	1000		2950
		UTM	2545	2051	2051	2205	2386	1579		3322
		grid
		Δ	-1145	-851	-801	-505	0	-579	-230	-372
		ODA	2516	1670	1500	2200	2300	--	--	--
	s.l.	UTM	3154	2414	2051	2205	2358	--	--	--
		grid
		Δ	-638	-744	-551	-5	-58	--	--	--
	Bufo spinosus	ODA	2600	1670	1800	1750	2200	1120	1120	2600
		UTM	3154	2414	2051	2205	2386	1579	1230	3322
		grid
		Δ	-554	-744	-251	-455	-186	-459	-110	-722
	Epidalea calamita	ODA	1700	1220	2000	2100	2386	1200	1200	2540
		UTM	2724	2157	2051	2205	2386	1579	1230	3201
		grid

Table 3 . Mean values and Standard Deviation (σ), and Coefficient of Variation (CV) of MAT (Mean Annual Temperature), MaxTW (maximum Temperature of the Warmest Month), MinTC (Minimum Temperature of the Coldest Month), and MAP (Mean Annual Precipitation), for each species of amphibians and reptiles identified in El Salt site according to the Portuguese Atlas (Loureiro et al. 2018) and in herpetofauna distribution server for Spain, SIARE (AHE 2021), ODA, and UDA. T-test significance level is calculated between values of ODA and UDA. Δ: Differences between the obtained results based on MER and ODA.

 3

		MER			ODA			UDA
	Alytes obstetricians s.l. MEAN σ		CV	MEAN σ		CV	MEAN σ		CV	T-test	Δ
	MAT (ºC)	11.95	2.69	22.51	12	2.63 21.92	5.01	2.27 45.31	0	0.05
	MaxTW (ºC)	26.22	3.05	11.63	26.27	2.99 11.38	19.52	3.17 16.24	0	0.05
	MinTC (ºC)	1.05	3.08 293.33	1.09	3.04 278.90	-5.11	2.04 -39.92	0	0.04
	MAP (mm)	777.63 294.71	37.90	774.54 293.32 37.87	1183.14 161.04 13.61	0	-3.09
	Bufo spinosus
	MAT (ºC)	13.11	2.89	22.04	13.14	2.84 21.61	5.7	2.52 44.21	0	0.03
	MTW (ºC)	28.17	3.82	13.56	28.21	3.78 13.40	21.33	3.99 18.71	0	0.04
	MTC (ºC)	1.84	3.18 172.83	1.87	3.14 167.91	-5.1	2.06 -40.39	0	0.03
	MAP (mm)	685.3 267.72	39.07	683.51 266.72 39.02	1023.48 237.67 23.22	0	-1.79
	Epidalea calamita
	MAT (ºC)	13.6	2.61	19.19	13.64	2.56 18.77	6.86	1.76 25.66	0	0.04
	MTW (ºC)	29.16	3.39	11.63	29.21	3.34 11.43	21.62	2.65 12.26	0	0.05
	MTC (ºC)	2.04	2.97 145.59	2.07	2.94 142.03	-3.6	1.59 -44.17	0	0.03
	MAP (mm)	622.74 236.63	38.00	620.05 234.83 37.87	1012.54 159.13 15.72	0	-2.69
	Blanus cinereus s.l.
	MAT (ºC)	14.98	2.12	14.15	15.03	2.03 13.51	8.22	2.2 26.76	0	0.05
	MTW (ºC)	31.29	2.54	8.12	31.33	2.5	7.98	26.07	1.84	7.06	0	0.04
	MTC (ºC)	3.12	2.69	86.22	3.18	2.62 82.39	-3.97	2.14 -53.90	0	0.06
	MAP (mm)	572.19 173.24	30.28	571.06 172.55 30.22	715.63 198.63 27.76	0	-1.13
	Chalcides bedriagai
	MAT (ºC)	14.28	2.52	17.65	14.35	2.44 17.00	7.81	1.79 22.92	0	0.07
	MTW (ºC)	29.29	2.88	9.83	29.34	2.84	9.68	24.46	2.49 10.18	0	0.05

Table 5 . Surface (ha) occupied by the different distribution units of each evaluated species. Reduction refers to the percentage by which the area occupied by the ecologically based distribution (ODA) has been reduced compared to that from UTM 10 × 10 km grids (UTM grid).

 5

		UTM grid	ODA	UDA	Reduction
	Alytes obstetricans s.l. 24,602,329.00	24,433,100.00	169,229.00	0.69
	Bufo spinosus	43,633,218.00	43,416,964.00	216,254.00	0.50
	Epidalea calamita	41,824,117.00	41,556,874.00	267,243.00	0.64
	Blanus cinereus s.l.	18,113,151.00	17,986,829.00	126,322.00	0.70
	Chalcides bedriagai	14,232,348.00	14,088,468.00	143,880.00	1.01
	Natrix maura	42,531,852.00	41,632,317.00	899,535.00	2.11
	Vipera latastei	14,615,103.00	14,387,799.00	227,304.00	1.56

Table 6 . Surface occupied by Northern (N) and Southern (S) slopes in the occupied distribution area (ha) of mutual distribution of the different studied assemblages of fossil herpetofauna from SU Xb and V of El Salt site, based on MER and ODA. ODA-MER reflects the differences between the occupied area of ODA minus MER.

 6

			N	S
		MER	112,736,424.93 134,344,164.13
	V-24 S3	ODA	110,820,493.10 133,128,296.75
		ODA-MER -1,915,931.83 -1,215,867.37
		MER	214,766,446.38 234,324,327.89
	V-24 S7	ODA	207,491,992.16 226,359,031.47
		ODA-MER -7,274,454.22 -7,965,296.42
		MER
	V-24 S8

  In fact, preliminary results of the present study, based only in the altitudinal limits for the whole Iberian Peninsula(Marquina- Blasco et al 2021b), without taking into consideration the different mountain ranges, provided results highly different from those presented in this work, at least for MAT and MAP from Xb-11 S3. In this case, MAT showed similar values (13.66 ºC in MER; 13.67 ºC inMarquina-Blasco et al. 2021b), whereas MAP was lower inMarquina-Blasco et al. (2021b) than in MER (756.27 mm and 762.68 mm, respectively). It denotes that UDA-ODA discrimination technique is highly dependent of the degree of refinement of the established ecological criteria for the definition of UDAs and ODAs. Considering this, it is necessary the development of new studies that define the actual altitudinal distribution of small mammals on each Iberian mountain system to verify if, as herpetofauna, we could obtain more realistic and precise data for this group. Moreover, in the case of herpetofauna almost all works about its altitudinal distribution only pointed out the maximum height reached by species; however, few of them are centred in the altitudinal distribution of determined taxa and/or its relation with the orientation of the mountains (i.e.[START_REF] Bea | Atlas de los anfibios y reptiles de Álava, Vizcaya y Guipúzcoa[END_REF].

ACKNOWLEDGEMENTS

Research at El Salt is funded by the Spanish Government project HAR2015-68321-P (MINECO FEDER/UE), UV-INV_AE17-708551 (Universitat de València) and Conselleria d'Educació, Investigació, Cultura i Esport from the Valencian government. This investigation was also carried out thanks to the Prometeo Project of the Secretariat for Higher Education, Science, Technology and Innovation from Ecuador and the University of La Laguna (Tenerife, Spain). The authors are grateful to the El Salt excavation team for their help with the excavation, sieving and washing of sediment each year. We thank the editor and two anonymous reviewers for their comments, which greatly improved this manuscript.

MAP (mm)

219.10 137.50 305.31 137.50 148.95 Comparing values obtained for the units analysed, in both methods MAT and MinTC for the modern samples (SU V) are lower than the older ones (SU Xb); however, as mentioned above, the values obtained in ODA are higher than MER. The palaeoclimatic reconstruction seems to draw a scenario of an alternation of moments with higher temperature (Su Xb-11 S3, V-24 S8, and V-25) with others of lower temperatures (V-24 S9 and V-24 S8). The main differences between methods are related with the parameters MaxTW and, especially, MAP. Regarding to the first, the values are similar in all samples except for V-24 S8. In this latter, MaxTW is higher in ODA (27.70 ºC) than in MER (27.19 ºC).

In this sense the changes recorded by ODA for this bioclimatic parameter is more similar to the observed for MAT and MinTC. For MAP the values are more constant between the different studied assemblages. That is in MER the difference between the maximum and minimum values is 167.81 mm (maximum value in V-24 S8, 848.89 mm, and minimum value in V-24 S9 and S7, 681.08 mm), whereas in ODA is 66.11 mm 828.49 mm,762.38 mm).