Radiocarbon dating.

AMS radiocarbon dating was conducted in the Poznań Radiocarbon Laboratory (Poland). The dating material included snail shells, human and animal bones, charcoals and one example of organic char residue preserved on the internal surface of the ceramic pot[58]. In the case of snails, each dating was performed on one identifiable shell of Isognomostoma isognomostomos. Shells of Discus ruderatus were also dated, but due to their small size, several shells from the same layer, square meter and depth were mixed together. A small aliquot of each shell sample was checked with X-ray diffraction (at the Faculty of Geology, University of Warsaw, Poland) prior to dating to exclude any material with negative effect of aragonite-to-calcite recrystallization. Only samples evidencing pure aragonite were dated. Chemical pretreatment followed Brock et al.[66]. In the case of bones, the dated fraction was collagen extracted according to Goslar et al.[67]. Small aliquots of extracted collagen were analyzed with a CHNS elemental analyzer, and atomic C:N ratios was calculated to check the collagen quality. The range of 2.9–3.6 was assumed acceptable according to the literature[68,69]. For two samples, the collagen yield was too low for both elemental analysis and radiocarbon dating, and these samples were dated without the C:N ratio being confirmed. In the case of charcoals, cellulose was extracted according to AAA method[66].

All dates were calibrated using the OxCal v. 4.3 software package[70] versus the IntCal’13 radiocarbon calibration curve[71]. Calibrated dates are presented as ky BP (i.e., thousand years before 1950), as the ranges within a 94.5% probability interval. The OxCal v. 4.3 sequence model was applied to estimate the chronology of layer boundaries. It followed the procedure used by Krajcarz et al.[72], based on the widely accepted methodology[73,74].

Luminescence dating.

The luminescence dating of samples was subcontracted to the Department of Geoecology and Palaeogeography, Maria Curie-Skłodowska University (Lublin). Post-IR IRSL₂₉₀ dating was performed on the polymineral fine grains (4–11 μm). The extraction procedure followed the accepted methodology[75]. Equivalent doses were determined using a post-IR IRSL protocol[76].

Identification of mollusk remains.

Standard methods[77–80] were applied for mollusk analysis. The shells collected during sieving were carefully cleaned. All completely preserved shells and their identifiable fragments were identified under a binocular microscope using taxonomical keys[81–83] and counted applying the schemes for broken individuals[77,80]. The number of individuals was counted separately for each layer. For some damaged individuals, only the genus or family levels were determined, and the calcareous plates of slugs were counted together under the heading of Limacidae.

Identification of rodent remains.

The rodent fossil assemblage consists of single bones and isolated teeth. Specimens were identified in terms of skeletal elements and species when possible. The taxonomical attribution of remains was based on the following diagnostic elements: first lower molars (Arvicolinae); mandibles, maxillae and isolated teeth (Muridae, Gliridae and Dipodidae); mandibles, maxillae, isolated teeth and diagnostic postcranial bones (Cricetus cricetus, Sciurus vulgaris). Remains were identified under a binocular microscope with use of the comparative collection of recent rodents and following the general criteria given in the identification keys[84,85]. The separation of Microtus arvalis and M. agrestis was based on the method given by Nadachowski[86,87]. The taxonomic classification followed Wilson and Reeder[88] for all taxa except for Clethrionomys glareolus (former Myodes glareolus) and Lasiopodomys gregalis (former Microtus gregalis), which were classified after later publications[89,90].

For each species, the number of identified specimens (NISP) and minimum number of individuals (MNI) were counted according to accepted method[91,92]. The MNI was counted separately for each layer.

Identification of bat remains.

Specimens were identified, when possible up to the species level, on the basis of diagnostic traits of the hemimandible and/or the skull. In particular, the attribution of the taxonomic group was based on several different characteristics: the number of teeth, the shape of the hemimandible, the traits of the fourth lower and upper premolars and those of the upper and lower molars. Remains were identified and measured through a binocular microscope, comparing them with specimens belonging to a collection of recent bats. The general criteria given in the identification keys[93–95] were fulfilled, and the remains were classified taxonomically according to Wilson and Reeder[88]. The taphonomic parameters NISP and MNI were calculated according to the same method as for rodents.

Paleoecological reconstruction.

Paleoecological inference was based on the environmental preferences of all mollusk, rodent and bat species found in the sediments. The structure of taphocoenoses and succession were presented on frequency bar diagrams. The diagrams were composed of both the absolute numbers of shells (or the MNI in the case of rodents) for samples containing less than 50 individuals and the percentages of the total sum for those with more than 50 individuals. In the case of bats, only the MNI values were shown due to low number of remains. Mollusk, rodent and bat assemblages were distinguished on the basis of their structure and composition, supported by statistical clustering analyses. The clustering was done for samples (layers) with more than 10 shells or with MNI greater than 10 by applying a paired group algorithm and Horn’s overlap index for abundance data using the PAST software package, version 3.22[96,97]. Both the character and succession of the assemblages were used in the paleoecological and paleoclimatic reconstructions.

To reconstruct the changes in ecological diversity in the stratigraphic sequence, the assemblages were analyzed via application of the richness and the Simpson index of evenness. In the case of rodents, specimens identified as M. agrestis/arvalis were excluded, while Apodemus sylvaticus/flavicollis and Apodemus sp. were counted as one taxon (genus Apodemus). The number of taxa per sample (layer) is a measure of richness. The greater the number of taxa present in a sample, the 'richer' the sample. The Simpson 1-D index was calculated as 1 − Σ(n_i/n)², where n_i is the MNI of the particular taxon in an ‘i-sample’ (a layer) and n is the total number of MNIs in a sample (a layer)[97]. The index was calculated using the PAST software package, version 3.22. The index represents the probability that two individuals randomly selected from a sample will belong to different taxa.

To present the changes in the environment or landscape around the site, we used the environmental preferences of the species. Each mollusk taxon was assigned to one of four ecological groups[80]: F–shade-loving species; O–open-country species; M–mesophilous species; H–hygrophilous species. In the case of rodents, which usually inhabit a range of environments, we used the method of habitat weightings[98]. Each taxon was assigned to the habitat(s) where it can be found at present, with percentage weight(s) attributed for each of its habitat(s) (details are provided in S3 File). The rodent fauna of ShSIII was assigned to eight habitat types based on a habitat identification mode provided in the literature[99–101], with modifications for habitats typical for Central and Northern Europe. The used habitats were as follows: Tu–tundra; OA–open anthropogenic cultivated areas; OD–open dry (steppes); OH–open humid (meadows); OW–open woodland (shrubs, forest margins, steppe-forests); FT–temperate forest (broadleaf forests, mixed forests); FB–boreal forests (taiga); Wa–water bodies. Data on the species distribution and their preferred habitats were taken from Mitchell-Jones et al.[102] and the International Union for Conservation of Nature (IUCN) Red List maps[103,104,105–112,113–121].

Bats with their flight ability are more mobile animals and this restricts their usefulness as the indicators of local paleoenvironment. However, some species which are sedentary and use old trees as summer roosts (i.e., Barbastella barbastellus, Myotis bechsteinii and Plecotus auritus) clearly indicate the presence of old-growth forests in the vicinity[122–124]. Bats hunting near water (M. dasycneme and M. daubentonii) indicate the presence of open water bodies[125,126].

Entrance zone.

The lower parts of the sedimentary sequence are similar at the entrance and central zones (Fig 4). The sediments of the upper part in the entrance zone are darker and more enriched in humus, as a result of the greater influence of external conditions and pedogenic processes. The total thickness of the sequence reaches 260 cm.

Layer 9 is a limestone debris composed of coarse sharp-edged clasts. The matrix is a yellowish brown to brown (Munsell color: dry 10YR 5/4-6/4, moist 10YR 5/3-5/4) silty loam to sandy silt. The limestone bedrock below the layer is cracked into angular blocks, and this regolith passes into layer 9 gradually, which is marked by decreasing size of blocks and occurrence of matrix. The Ca content is very high in the fine fraction, particularly in the lower part of the layer, where it reaches greater than 30% (Fig 5). This strongly suggests that the fine fraction is mostly composed of physically disintegrated limestone.

Layer 7 is a pale brown to brown (dry 10YR 6/3, moist 10YR 4/3) sandy silt. It is a massive (structureless) loess-like sediment with angular limestone clasts. Layer 9 passes indistinctly into layer 7, and the transition between the layers is marked by a gradual color change and decreasing amount of limestone clasts. The content of Ca in the fine fraction is very low (Fig 5), which indicates the allogenic source of material. At squares C/5 and partially D/5, a lens of dark silt (called layer 8) occurs in the upper part of layer 7. This intercalation enables dividing the layer locally into sublayers 7a (above layer 8) and 7b (below layer 8).

Layer 8 is a grayish brown to dark grayish brown (dry 2.5Y 5/2, moist 10YR 4/2) sandy silt. The texture is similar to that of layer 7, except for the dark color and the presence of charcoals inside layer 8.

Layer 3a is a grayish brown to black (dry 10YR 5/2, moist 10YR 2/1) silt. The amount of limestone clasts is greater than in layer 7. Angular blocks predominate, but smoothed clasts also occur. The concentration of P increases upward starting from layer 3a (Fig 5), indicating the increasing impact of zoogenic activity on the accumulation. The lower boundary is blurred, and the layer passes downward gradually into layer 7. Close to the walls of the rockshelter, the layer exhibits greater thickness, and its bottom is situated at lower elevation.

Layer 3 is a dark brown to very dark grayish brown (dry 10YR 3/2-4/3, moist 10YR 2/2-3/3) sandy silt. The amount and size of limestone clasts is lower here, and smoothed clasts occur in greater number (Fig 5). However, outside of the dripline (square meters C/4 and partially D/4), the large limestone blocks occur in the layer. Their surfaces and edges are smoothed. Indistinct trough cross-stratification is marked in the bottom part at square E/4.

Layer 1 is a very dark gray to black (dry 10YR 3/1, moist 2.5Y 2/1) silty sand. Limestone debris becomes less abundant and finer upward, and angular clasts are almost lacking, while smoothed, rounded-like clasts are relatively abundant. This layer exhibits unusually high concentrations of Pb and other toxic metals (Zn, Cd, Ag, Sb, Bi, Sn, see Fig 5), suggesting an increased impact of human activity. Another characteristic of the layer is a high sand fraction.

Central zone.

The lithological variability is the greatest in this area, and the stratigraphy is the most complex, with up to eight distinct strata preserved in superposition (Fig 4). The lower part of the sequence shares lithological characteristics with the entrance zone, but in the upper part, the sediments are different. The sedimentary fill achieves a thickness similar to that of the sediments in the entrance zone (230 cm at maximum).

The sequence starts with a limestone debris containing very pale brown to yellowish brown (dry 10YR 8/3, moist 10YR 5/6) silty to sandy matrix (called layer 9), which is a continuation of layer 9 from the entrance zone. The clasts are finer here, but angular shapes still predominate (Fig 5). The layer reaches the greatest thickness (110 cm) at squares E/6, F/6 and F/7, where it fills the narrow and deep depression of the bedrock, probably a remnant of a vadose canyon.

The overlying sediment (called layer 7) is a continuation of layer 7 from the entrance zone. It is a yellowish brown to pale brown and brown (dry 10YR 6/3, moist 10YR 4/3–5/4) loess-like sandy silt with limestone clasts. The clasts are mostly angular and become less abundant and finer upward (Fig 5). The concentration of Ca in the fine fraction is very low (Fig 5), which suggests an allochthonous source of fine material. The lower boundary of this layer is indistinct, and layer 9 passes gradually into layer 7. Similar to the entrance zone, locally (at square D/5, where layer 8 occurs), the layer can be divided into sublayers 7a (above layer 8) and 7b (below). Sublayer 7a has a lighter, more yellowish color (dry 10YR 6/3, moist 10YR 5/4) and lower amount of limestone clasts compared with sublayer 7b (color: dry 10YR 6/3, moist 10YR 4/3). The lower boundary of sublayer 7a is not always readable, but locally, especially in contact with layer 8, it is sharp and erosional.

Layer 8 is probably a continuation of layer 8 from the entrance zone. It is a grayish brown to dark grayish brown (dry 2.5Y 5/2, moist 10YR 4/2) sandy silt. It occurs in restricted area, limited to square D/5. The layer seems to fill the shallow depressions in sublayer 7b. The remains of a hearth are preserved in the lower part of layer 8 and labeled as sublayer 8a.

Layer 6 is a light brownish gray to dark grayish brown (dry 10YR 6/2-6/3, moist 10YR 4/2–2.5Y 5/2) sandy silt. The amount, size and morphology of limestone clasts are similar to layer 7 (Fig 5). The concentrations of Ca and P increase from layer 6 upward, recording the increasing importance of autogenic deposition and zoogenic activity. The lower boundary of layer 6 is sharp and undulating. Internal sedimentary structures in a form of trough cross-stratification are weakly marked inside the layer.

Layer 5 is a grayish brown to dark grayish brown (dry 10YR 5/2-5/3, moist 10YR 4/2-4/3) silty loam to sandy silt. The amount of limestone debris is greater than in layer 6 (Fig 5). The clasts are smoother, and even rounded-like ones occur. The lower boundary is discordant, sharp and undulating. The trough cross-stratification is locally distinct, with bedding inclined toward the entrance.

Layer 5a is a whitish to grayish brown and dark grayish brown (dry 10YR 5/2-8/2, moist 10YR 4/3-6/3) massive silty loam to clay silt. The sediment is clearly lighter in color than those of the lower strata. Its lower boundary is sharp, and the layer lies discordantly on lower sediments. Locally, layers 5 and 6 are not preserved, and layer 5a lies directly on layer 7. The amount of limestone clasts is relatively low, and the clasts are fine and smoothed (Fig 5). The concentrations of Ca and P are among the highest in the entire sequence. The layer is not continuous and is lacking at square meters D/5, D/6 and E/6.

Layer 4 is a very pale brown to brown (dry 10YR 7/3, moist 10YR 5/3) massive silty loam. The amount of limestone clasts is low; their morphology is similar to that in layer 5a (Fig 5). The clay content increases in the upper part of layer 5a and stays high in layer 4 (Fig 5). The concentration of Ca is similar to that in layer 5a, whereas the concentration of P is slightly lower (Fig 5). The lower boundary is indistinct and gradual.

Layer 2 is similar to layer 4 in terms of the grain size composition and limestone clast morphology (Fig 5) but differs in color, being more grayish (dry 2.5Y 7/2, moist 2.5Y 4/2). The concentrations of Ca and P are still relatively high but lower than in layer 4. The boundary between layers 2 and 4 is indistinct and gradual.

The sequence is topped with layer 1a, which is a lateral variant of layer 1 from the entrance zone. This sediment is more brownish than layer 1 (dry 2.5Y 3/2, moist 2.5Y 2/2). The thickness of layer 1-1a decreases toward the rockshelter interior, such that the maximum thickness of layer 1 is 60 cm and that of layer 1a is up to approximately 30 cm. Upper part of layer 1a covers the archaeological feature (layer A), and due to lithological similarities of these two units, the boundaries between them are difficult to follow.

Rear zone.

The sequence in the rear zone has a reduced thickness, achieving 120 cm at maximum (Fig 4). Sediments of this zone were recognized in a limited area of approximately 1 m². The rockshelter is shaded, and sunlight does not reach this area. The corridor declines downward to the south and becomes narrower, down to the width not accessible for penetration by an adult human. The concentration of K is low in this zone, which indicates lower infiltration from the top strata, possibly as a result of low rainwater supply in the deeper part of the rockshelter.

The sequence starts with layer 11, which is a complex stratum of bright reddish-brown color. The average grain size composition indicates a silty loam texture, but the layer is composed of numerous diapirs of brown (dry 7.5YR 5/4, moist 7.5YR 5/4) clay and lenses of reddish brown to strong brown (dry 7.5YR 6/6, moist 7.5YR 5/6) silty sand. This sandy component is most likely an admixture from layer 10. Limestone clasts are absent. The sediment is strongly enriched in Fe and depleted in Ca (Fig 5), what indicates an allogenic origin. High concentrations of Fe and other geochemically related metals (Mn, Co, Zn, Pb, Cu, Mo, Th, Cd, Sb, and REE) are characteristic features of this sediment and are responsible for its reddish color. The thickness is greater than 30 cm.

Layer 10 is a yellow to brownish yellow (dry 10YR 7/5, moist 10YR 6/7) silty sand. Sandy grains are composed mostly of quartz. Such a mineral composition, together with the lack of limestone clasts and very low concentration of Ca (Fig 5), indicates an allogenic origin. The sediment is preserved only in pocket-like or tongue-like structures immersed in layer 11. The contact between the two layers, although not in a primary position, is sharp, what indicates the erosional boundary at the bottom of layer 10. The original thickness of the layer is difficult to establish due to disturbances, but it can be estimated to be greater than 5 cm.

Layer 9 is a 15-cm-thick horizon of coarse subangular limestone blocks, with yellowish brown to dark yellowish brown (dry 10YR 5/3, moist 10YR 4/4) silty loam filling the space between blocks. The lower boundary is sharp and erosional. The vertical orientation typical for layers 11 and 10 is not visible here. High concentrations of trace metals, similar to those exhibited by layer 11 (Fig 5), indicate that layer 11 served as important source of material. This layer most likely forms the lateral continuation of layer 9 from the entrance and central zones.

That layer passes upward gradually into layer 4. This is a very pale brown to yellowish brown (dry 10YR 7/3-7/4, moist 10YR 5/4-5/5) silt or clay silt, passing upward into silty loam. This layer is a lateral continuation of layer 4 from the central zone. The concentrations of Ca and P are high and increase toward the top of the layer.

Layers 2 and 1a are lateral continuations of layers 2 and 1a, respectively, from the entrance zone and share lithological characteristics with those strata.

Anthropogenic layers.

Two anthropogenic strata were recognized between the natural strata and were labeled as sublayer 8a of layer 8 and layer A.

Sublayer 8a is a black (dry 10YR 4/1, moist 10YR 2/1) sandy silt. It occurs in the lower part of layer 8 and represents its darker variant. The sublayer has a form of a thin lens with a thickness of approximately 10 cm and lies at the bottom of a shallow depression dug into layer 8 and reaching sublayer 7b. The presence of charcoals indicates that this deposit is a remnant of a hearth.

Layer A is a sediment of intermediate characteristics between layers 1, 1a, 2 and 3. It is a dark brown to very dark grayish brown (dry 10YR 3/1-4/3, moist 10YR 2/2-3/2) silty sand. It forms a backfill of an anthropogenic feature. Its lower boundary is sharp and distinct. Stratigraphically, the feature is situated inside layer 1-1a, as its walls cut layer 1 or 1a, and at some square meters, it is covered by the upper part of layer 1a, with an indistinct boundary between the layers. The bottom of the feature reaches layer 2 or 3 (at different square meters) and occasionally layers 4 and 5a.

Assemblage Vt.

The sequence starts with the assemblage with Vallonia tenuilabris (Vt), including layers 7b, 8, and 7a in the central zone and layer 8 in the entrance zone; possibly also layers 7a and 7b in the entrance zone belong to the same assemblage. This poor malacocoenosis contains from 5 to 60 shells per layer (Fig 7), mostly of open-country gastropods, which constitute 35–73% of all individuals. Vallonia tenuilabris, a glacial relic that occupies the open areas of so-called “cold-steppes”, the alpine grasslands, taiga, hemiboreal forest and wooded fens[77,131–134], is the most numerous in the central zone, being accompanied by the shade-loving species Discus ruderatus and Semilimax kotulae, both characteristic of a cool and continental climate. In the entrance zone, D. ruderatus slightly outnumber V. tenuilabris (Fig 7).

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Fig 7. Paleoecological indicators for ShSIII based on mollusk remains.

Data are arranged by the zones and the order of layers. Representation of taxa reflects the percent of individuals. Dark gray bars are used for shade-loving, medium dark for open-country, light gray for mesophilous and white for hygrophilous taxa. “+” means that the taxon is represented in the given layer but the total MNI for the layer is lower than 50, so the representation is not statistical. Numbers in parentheses indicate the number of individuals higher than 1 for statistically non-representative layers. Measures of the paleoecological diversity (richness and Simpson index), representation of habitats and attribution of layers to mollusk assemblages are also shown.

https://doi.org/10.1371/journal.pone.0228546.g007

Assemblage DrVc.

In layers 6, 5 and 3a, another assemblage dominated by Discus ruderatus and Vallonia costata (DrVc) can be distinguished (Fig 7). D. ruderatus represents taiga-type coniferous forests, whereas V. costata is typical of dry and open habitats and predominates in the sequence. In the central zone (layers 6 and 5) glacial relics V. tenuilabris and S. kotulae are still important components of the assemblage, but they disappear in the entrance zone (layer 3a). Moreover, this assemblage records a first period of predominance of shade-demanding species in the sequence (Fig 7). Mesophilous snails are mostly represented by Carychium tridentatum, associated with permanent humid conditions [83] (S2 File).

Assemblage DroAp.

A rich assemblage with Discus rotundatus and Aegopinella pura (DroAp) can be distinguished in layers 5a and 4 of the central zone and the lower part of layer 3 in the entrance zone. This assemblage is represented mostly by forest gastropods (52–75% of all individuals) typical of warm and humid conditions, namely, D. rotundatus, A. pura, Discus perspectivus, Balea biplicata, Helicigona faustina and Isognomostoma isognomostomos. V. costata gradually disappears, and the open-country snails become outnumbered by mesophilous species, mainly Laciniaria plicata (Fig 7). The occurrence of V. elata, unknown in the contemporary fauna of the region, is worth noting.

Assemblage Lp.

The topmost part of the sequence (the upper part of layer 3 and layers 2, 1a and 1) is occupied by forest and mesophilous taxa, with the most numerous being Laciniaria plicata (Lp). Gastropods of open habitats disappear in the central zone and are of secondary importance in the entrance zone. The forest fauna still comprise a large fraction of the total fauna (45–61% of all individuals) but are gradually replaced by snails of wide ecological tolerance, which are the most abundant in layers 1a and 1 (up to 55% of all individuals) (Fig 7). L. plicata, which is typical of humid rocks in open environments, is accompanied by Helicigona lapicida, which often hides in deep crevices in shady rocky substrate; H. faustina, which is common in forest slopes and humid shady rocks; and I. isognomostomos, which is characteristic of humid mountain forests (Fig 7 and S2 File).

Assemblage Dt.

This assemblage groups layer 8 and sublayer 7b from the central zone. Sublayer 7a from the central zone and layer 7b from the entrance zone possibly also belong to this assemblage. From a quantitative point of view, this is a very poor collection, giving altogether 38 remains (at least 29 individuals). The dominant taxon here is a collared lemming Dicrostonyx torquatus (30.8–100% of MNI for sublayers 7a and 7b), followed by the tundra vole Microtus oeconomus and European water vole Arvicola amphibius (Fig 8). Collared lemming is an inhabitant of cold climatic areas, while the two other voles prefer humid habitats with water bodies. The relatively high representation of the red vole Clethrionomys glareolus in layer 8, which is linked with woodlands and prefers densely vegetated clearings, suggests a possible temporal climatic improvement with development of woodland vegetation. Inhabitants of open dry environments (steppes), i.e., Cricetus cricetus and Sicista subtilis, were recorded in sublayer 7b.

Assemblage CgLg.

Layer 6 forms a separate assemblage. The number of rodent remains is low (51 remains, at least 25 individuals). There is a well-distributed diversity, even if the number of species is low. The assemblage is dominated by C. glareolus (28% of MNI). The second-most-abundant species is Lasiopodomys gregalis (16%), a representative of open and cool habitats. Rodents adapted to cold or boggy environments (D. torquatus, A. amphibius and M. oeconomus) are still present. Thus, the layer records a sensible increase in the woodland component (Apodemus and C. glareolus constitute 30% of the MNI) (Fig 8). Layer 4 from the rear zone is grouped by cluster analysis with this assemblage, however, the number of specimens is low (15 remains, at least 11 individuals) and this clustering is disputable.

Assemblage CgMs.

A rich assemblage dominated by C. glareolus and M. subterraneus is recorded in layers 3a, 3 and 1 in the entrance zone, layers 5, 5a and 4 in the central zone. Layer 2 from the rear zone is poor in rodent remains but possibly also represents this assemblage. The species of cold habitats disappear. There is a visible rise in the representation of taxa associated with woodland environments, with domination of the red vole, C. glareolus. This is the most abundant taxon in the whole upper part of the sequence. Starting from layer 5 in the central zone and 3 in the entrance zone upward, the red vole is followed by M. subterraneus, also an inhabitant of woodlands, preferring densely vegetated clearings. Mice of genus Apodemus also constitute a significant portion of the assemblage. The development of deciduous or mixed forest habitats is testified by the presence of three species of the Gliridae family, which continues in the upper layers of the sequence (Fig 8).

Assemblage CgMsGg.

The layers of the uppermost part of the sequence in the central zone (2 and 1a) are characterized by another rodent assemblage. The species representation is similar to the lower assemblage CgMs, and the record of habitat conditions did not change significantly. The visible change is recorded by the higher participation of the edible dormouse Glis glis. In layer 1 of the entrance zone and layers 2 and 1a of the rear zone the presence of this species is also marked, which suggests their correlation with CgMsGg assemblage. However, the amount of edible dormouse remains is not as high there as in layers 2 and 1a in the central zone, and therefore the cluster analysis joins these layers with other assemblages (Fig 8 and S3 File).

Assemblage PaurMbra.

The group comprised by layers 4 and 5a contains the richest assemblage in terms of number of remains, even if the number of species does not differ from the overlying layer 2 (Fig 9). We found 79 individuals belonging to 9 species, for a total of 130 bone remains.

Assemblage MbecPaurMbra.

Layer 2 in the central zone seems to be one of the richest layers in terms of a number of remains (NISP = 61, represented by 38 individuals belonging to 9 species). The only fragment attributable to P. pipistrellus/pygmaeus (the identification of the species is impossible due to a lack of the distinctive characters) was found in this layer.

Assemblage MdauMbra.

This assemblage represents layer 1a from the central zone and is comparable to the one found in layer 1 from the entrance zone (i.e., the PaurMdas assemblage). A small number of remains (16 fragments) were found. They belong to 12 individuals of 6 different species (Fig 9).

Assemblage BbarMdas.

The lower part of layer 3 from the entrance zone delivered few fragments (16) belonging to 12 individuals of 8 species. This assemblage does not differ considerably from the other layers of the entrance zone (Fig 9).

Assemblage PaurMdauMdas.

This assemblage, belonging to the upper part of layer 3 in the entrance zone, includes a small number of specimens (16 bone fragments attributable to 13 individuals of 6 different species) (Fig 9).

Assemblage PaurMdas.

This assemblage represents layer 1 from the entrance zone. From a quantitative point of view, this is a very poor collection, with only 16 remains belonging to at least 15 individuals (Fig 9). A predominant taxon cannot be defined.

Series I–reddish clays.

The oldest sediments are preserved in the rear zone as layer 11. This sediment shares similarities with reddish clays known from the lowermost parts of the sequences from caves such as Biśnik Cave (layers 20–23)[26], Nietoperzowa Cave (layer 17)[20], Tunel Wielki Cave (lower part of layer 1)[21], Cave in Dziadowa Skała (lower part of layer 1)[135] and Żabia Cave (lower part of sequence)[136]. These types of sediments were linked with Lower Pleistocene or Pliocene terra rosa soils, redeposited to the caves from the surface[137,138].

Series II–sands.

Layer 10 has also been preserved only in the rear zone. The bright color of sand suggests a correlation with reddish or yellowish sands known from other caves of the region, where they also form a bottom part of the sequences. Such sandy deposits are known from caves such as Nietoperzowa Cave (layer 17)[20], Koziarnia Cave (layer 21)[20], Tunel Wielki Cave (upper part of layer 1)[21], Perspektywiczna Cave (layer 11)[46], Cave in Dziadowa Skała (upper part of layer 1)[135] and Wylotne Rockshelter (layer 8)[20]. The accumulation of sands may be connected with Middle Pleistocene glaciations, when the area of Kraków-Częstochowa Upland entered the fluvioglacial regime[51,52,139], or with later colluvial redeposition of fluvioglacial sediment. Both layers 11 and 10 fill the narrow depression of the bedrock, a form which was called a “bottom rill”[140] and which is most likely the remnant of a vadose canyon. This depression was also noticed in the central zone, but here, the sediments resembling layers 10 or 11 have not been preserved. The depression is filled with limestone debris of layer 9, which also occurs in the rear zone, but with limited thickness and at higher elevation. This result indicates that erosional event happened between accumulation of layers 10 and 9, which was responsible for almost total removal of layers 10 and 11, except for the rear zone.

Series III–limestone debris and loess.

Layer 9 records the cold climatic conditions. A high amount of angular limestone clasts with Ca-rich silty matrix indicates that physical weathering of the bedrock and consequential rockfall was the most important depositional factor, followed by physical weathering of the rockfall debris. An absolute lack of faunal remains additionally suggests very cold periglacial conditions. This sediment may be correlated with layer III from the nearby Shelter above the Zegar Cave[141], described as loess with limestone debris, with very sparse faunal remains. The reddish color of layer 9 suggests that layer 11 (and possibly also layer 10) served as an additional source of material for layer 9. Most probably, some remnants of layers 11 and 10 survived the erosion adhered to the walls or inside the niches and dropped down during the deposition of layer 9. A similar situation concerning the Lower Pleistocene red clays redeposited into the Upper Pleistocene series was described for Tunel Wielki Cave[21,29]. Debris of layer 9 filled the deep vadose canyon cleaned by the previous erosion and achieved over 1 m thickness inside the depression, but it reached only limited thickness on the elevations, such as in the rear zone.

Layer 7 was deposited on the uneven surface of the rockfall debris and filled the depressions. The layer achieves the greatest thickness near the entrance and becomes thinner toward the cave interior. It disappears at a distance of approximately 300 cm from the dripline. It is a loess-like sediment or “cave loess”[27]. Respecting the lithostratigraphic scheme of those authors, the lower part of layer 7 (with limestone debris) correlates with their unit A, and its upper part (less debris, more silt) with unit C. Analogous sediments occur in a number of caves in the region, including the closest ones: Biśnik Cave and Shelter above the Zegar Cave[26,141]. Indistinct lower boundary with layer 9 indicates gradual change in sedimentary environment from physical disintegration of the bedrock related to cold and humid climate[6] to eolian accumulation typical for cold and dry conditions.

Intercalation of dark-colored layer 8 allows dividing layer 7 into sublayers 7a and 7b, but this possibility occurs on a limited area. Sublayer 8a in the lower part of layer 8 represents an anthropogenic activity. This deposit was formed by firing a hearth in a shallow pit dug in the loess. Few faunal remains have been found in layer 8. These include both the bones of larger mammals (hare and elk), which may be related to human hunting activity but also the remains of rodents and snails, likely deposited by natural agents. Presence of fauna and charcoals records a temporal climatic warming, replaced later again by periglacial conditions as marked by the overlying loess of layer 7a. Trough cross-stratification visible in sublayer 7a also indicates a role of colluvial processes in the formation of this stratum.

Series IV–colluvial sediments.

Holocene sequence starts from layer 6, as indicated by radiocarbon dating (Table 1) and explosion of the abundance and diversity of faunal remains (Fig 11). Trough cross-stratification and lamination in layers 6 and 5 are distinct indicators of erosion and colluvial redeposition of sediments by washing and/or mudflows. Inclination of sedimentary structures indicates that the main direction of a geological transport was oriented from the rear zone of the rockshelter to the entrance and probably outside. Redeposited material differs from any lower sediment by the higher amount of organic matter, Ca and P. This result means that before the redeposition, but after the sedimentation of layer 7, another type of sediment was accumulated in the rockshelter. The original strata did not survive the denudation, but their material has been preserved in a form of layers 6 and 5. The source of this material was most likely situated in the rear zone.

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Fig 11. Summary distribution of radiocarbon probabilities for ShSIII.

Calibrated dates are used. PHA are phases of human activity, described in the section “Chronometric data”.

https://doi.org/10.1371/journal.pone.0228546.g011

This series represents a period of geomorphological instability, when episodes of erosion and colluvial redeposition alternated several times in the rockshelter. The reason for these processes was likely high water supply, possibly linked with humid climate or degradation of the Pleistocene permafrost[3]. The series is topped with an unconformity, which may be regarded as the last record of erosional-colluvial activity. Records of analogous processes were recognized in other cave sites in the region[27] and linked with the lithostratigraphic unit E of the loess-like cave deposits.

Series V–massive loams.

Massive (structureless) silts and loams with limestone debris of layers 5a, 4, 3a, 3 and 2 represent another series. No sedimentary macrostructures except for interlayer boundaries are visible, and even these boundaries are indistinct and gradual. This indicates a low sedimentation rate and slow or almost ceased geological transport. High amount of limestone clasts and high Ca content in the fine fraction support a hypothesis of an autochthonous source of the clastic material. A high concentration of P indicates intense zoogenic accumulation of excrements of cave dwelling animals and/or carcasses of their prey. The limestone clasts are smoothed and even rounded-like. Madeyska[29] linked the smoothing process with both mechanical erosion and chemical dissolution by dripwater and a generally humid and warm climate[63]. Layers 5a and 4 are particularly distinct due to their bright color and higher amount of clay. Increased content of clay and yellowish color indicate chemical weathering of limestone, i.e., the dissolution and removal of carbonates, accompanied by deposition of water-insoluble clay residuum enriched in Fe oxides. The bright color and higher amount of clay in cave sediments are regarded as an indicator of warm climate[56] and allow correlating of these layers with the Holocene climatic optimum.

In the entrance zone, the stratigraphy is less distinct due to pedogenesis (see the section “Pedogenesis” below). Noteworthy is the presence of large limestone blocks in layer 3. Some of them reach more than 90 cm in diameter. These blocks represent a massive rockfall event. Other large blocks (some of them longer than 1.5 m) protrude from the ground at the plateau in front of the rockshelter and possibly represent the same episode. As the excavation area uncovered only a limited part of this accumulation of blocks, it is difficult to conclude regarding its origin. It could represent the climatic conditions favoring physical weathering and disintegration of rock, i.e., a cold climate, but this is in contradiction with the record of a climatic optimum within the series. The tectonics can be excluded, as there are no signs of recent tectonic activity in the rockshelter, nor in the region. An alternative explanation is a catastrophic event, such as an accidental fall of a heavy block from the upper part of the hill, which could cause a massive avalanche.

Series VI–dark humus-rich top sediments.

The uppermost layers 1 and 1a differ from sediments of the underlying series V. The most impressive feature is their dark color, related to increased humus content. The sand fraction is clearly higher. The unusually high concentrations of Pb and other toxic elements (Ag, Bi, Cd, Sb, Sn, Zn) suggest an increased impact of human activity. However, no archaeological artifacts made from these metals were found in the rockshelter. This suggests indirect pollution from the outside. It may be noteworthy that lead, zinc and silver mining in the southern part of Kraków-Częstochowa Upland has been active at least since Middle Ages[142] and is still ongoing. This medieval and modern industry could have polluted the region, e.g., via an eolian activity. Sediments of this series contain detrital material, i.e., bones with quite early radiocarbon dates (Fig 6). These bones likely come from the backfill of archaeological feature, layer A, and testify later disturbance of the grave, possibly by burrowing animals.

Cryoturbation.

Although the thick series of sediments were connected with cold climate (layers 7 and 9), the traces of cryoturbation are restricted in the sedimentary profile. The only distinct disturbances caused by frost action are visible in layers 10 and 11. A complex of these layers together with frost structures are cut by the unconformity and covered by layer 9. This indicates that the cryoturbation event took place before the deposition of layer 9 and the preceding erosion.

Bioturbation.

Larger fossil burrows were found inside layers 5a and 5. The size of burrows suggests a constructor of a badger or fox size. These structures were filled with a sediment resembling layer 4. One of badger bones found inside one burrow gave a radiocarbon age of 5.0–4.8 ky BP (Poz-53303, Table 1). Some further dates obtained for layers 5a and 5 (Poz-61237 and Poz-61305) are consistent with dating of layer 4 (Table 1). These data allow correlating the burrowing activity with the deposition of layer 4 or a period soon after.

The presence of a brown bear skeleton[58] suggests that the rockshelter was used by bears as a hibernation den. It cannot be excluded that bears dug the hibernation pits and disturbed the sediments. However, the bones of a bear were found in a secondary position inside the backfill of an anthropogenic feature (layer A). The direct relationships between the bear remains and the sediments cannot be reconstructed.

An interesting example of the recent bioturbation are funnel-shape pits in the modern ground surface, dug in the layer 1a and filled with excrements, possibly of a badger. Two such structures were found during excavation, each approximately 20 cm deep, approximately 20–30 cm wide in the upper diameter and narrowing downward. The total volume of excavated excrements was approximately 10–12 liters. These pits can be interpreted as animal latrines. Production and use of such communal latrines is a known behavior of badgers[143,144]. Such badger activity might be responsible for the lateral scattering of some material from the backfill of the grave (layer A) throughout the rockshelter, and its incorporation into layer 1a.

Anthropogenic disturbances.

The first sediment-disturbing human activity in the rockshelter was related to PHA 1 and happened during the Late Paleolithic. It affected the loess layers 7b and 8 in the area close to the rockshelter entrance. The Paleolithic visitors dug an oval pit that served as a fireplace. This trough-like object had a diameter of 60 cm and a depth of 30 cm and must have been filled with loess sediment (layer 8a) soon after humans had left the site.

The second distinctive phase of the anthropogenic disturbances is related to the burial of a woman in the late Middle Ages (PHA 4). The grave was constructed in the central zone and covered an area of approximately 2 m² (at squares D/5, D/6, E/5, E/6 and E/7). The length along NE-SW line is approximately 200 cm, whereas the width along NW-SE line is approximately 100 cm, and the greatest depth reaches 60 cm. The object contacts the limestone walls of the rockshelter (the bedrock) from the west and south-west, while several larger stones that can be interpreted as a relic of a purposefully built wall have been found in the entrance zone, at the north side of the grave[58]. The boundaries of the grave cut primarily layers 1, 1a, 2 and 3 and partially layers 4 and 5a in the southern part. The object is filled with sediments named layer A (field numeration “1a/2” and such name was used in a previous paper[57]). Inside the entire backfill of the object, charcoal dust and fine charcoals were dispersed. Lithologically, the backfill resembles layers 1, 1a and 2, whose material was probably used to fill the grave. The backfill does not exhibit any visible stratification. This suggests a quick and single-event deposition of the sediment. Toward the bottom, the sediment becomes lighter in color and more clayey, similar to layer 4. This is probably a result of using the redeposited sediment of layer 4 during the initial filling. Archaeological material within the object is associated with different phases of human activity (PHA 2, PHA 3, and PHA 4, see Fig 11). It is mixed up and does not exhibit any systematic layout, except of human bones linked to PHA 4. This indicates that medieval people destroyed the earlier objects and used their backfills while constructing the grave. It seems probable that other features (perhaps graves or pits) associated with PHA 2 and PHA 3 were present in the central zone before the Middle Ages. However, the construction of the medieval grave completely consumed these older objects.

Pedogenesis.

In the entrance zone, the stratigraphy of the upper part of the sequence is obscured by dark coloration, related to a high content of organic matter. The dark color becomes gradually lighter downward from the top of layer 1 to the bottom of layer 3, which is also marked by the gradual decrease in organic matter (Fig 5). This indicates that the organic matter was dispersed in profile by illuviation. Layer 1 represents an A-horizon (topsoil) and layer 3 represents a B-horizon (cambic) of a cambisol. The development of the soil was (and still is) possible here due to localization outside of the cave, as layers 1 and 3 occur only in the entrance zone, close to the dripline or outside of it. Recently, this area has been covered by forest litter composed mostly of beech, maple and oak leaves (Fig 2).

Layer 3a possibly represents a separate, earlier phase of pedogenesis. This stage of soil development was possibly halted by the erosion recorded in the bottom of series V and/or the accumulation of large limestone blocks visible now inside layer 3 (see the section “Series V–massive loams” and Fig 4). Some strata situated inside the rockshelter, namely, layers 1a and A and to a lesser extent layer 2, are also dark-colored and enriched in organic matter. This enrichment can be an effect of occasional input of litter to the interior of the rockshelter or redeposition of the humiferous sediment of layer 1 from the entrance zone (or topsoil material from outside the rockshelter) by wind, sheet wash and/or walking animals and humans.

Chronological frame of the sequence.

The radiocarbon and IRSL dates indicate the Late Pleistocene and Holocene chronology of the sediments in ShSIII. Dates arranged by layers show a consequent chronological order (Fig 6). The only inconsistency that prevented the OxCal sequence model from running (two dates were removed from the model; see the section “Chronometric data”) is connected with layers 4-5a-5. It is noteworthy that these layers were a subject of bioturbation, as burrows filled with sediments of layer 4 were detected in layers 5a and 5 (see the section “Bioturbation”). That burrowing could be responsible for mixing of the subfossil material and observed chronological disorder. Two dates removed from the model (Poz-61237 and Poz-61305) were achieved on snail shells excavated from layers 5a and 5 but fit well to the set of dates for layer 4. These two dates likely represent intrusive material according to the terminology of Bronk Ramsey[74], in this case material from layer 4 that had been redeposited to the lower layers through animal burrows.

Pleistocene sediments.

No dates are available for the lowermost layers 9, 10 and 11. The chronology of these layers can be approximated as being older than the earliest date accessible for the upper strata, which is 28.9 ± 1.7 ky BP (Table 3). Layers 7b and 8 clearly represent the Late Pleistocene. The radiocarbon dates fall between 14.5 and 12.5 cal ky BP for both layers. Bayesian modeling estimates the age of lower boundary of this series to be between 16.2 and 13.8 ky cal BP with 95.4% probability (see Table 3 and the section “Chronometric data”). The IRSL dates indicate much older age of sublayer 7b, approximately 28–21 ky cal BP. These dates likely represent a periglacial conditions of loess accumulation, when biogenic material was not deposited. Loess accumulation in the region, including its eolian deposition within the caves, has been dated to 27–11 ky BP[27]. No dates are available for layer 7a. The modeled statistical age of this layer is between 12.7 and 10.2 ky cal BP (with 95.4% probability; see Table 3 and the section “Chronometric data”) and correlates with the Younger Dryas stadial and/or Preboreal phase of the Early Holocene[145].

Holocene sediments.

Radiocarbon dates indicate almost continuous accumulation of biogenic material through entire Holocene (Fig 11). The greatest gap in the probability distribution of radiocarbon age falls before 10.5 ky cal BP, i.e., in the beginning of Holocene.

Series IV (layers 5 and 6) includes the oldest Holocene sediments. The series was deposited during relatively short time interval according to radiocarbon dates, which lasted for several hundred up to a maximum of three thousand years (Table 3). The IRSL date achieved for layer 6 shows a much older age of clastic material than radiocarbon dating of animal remains (Table 2) and corresponds with the age of layer 7b. Regarding the colluvial origin of the series, this date can likely indicate a colluvial redeposition of the material of layer 7b, which has been incorporated into layer 6. A relatively early age is also indicated by the IRSL date for layer 5a. This age is earlier than any other date obtained for layer 7b and may possibly record another source of material (layer 9 or sediments occurring outside the rockshelter?). It is difficult to conclude on the sedimentary process responsible for accumulation of this material. No macroscopic traces of colluvial transport were identified. The important role of zoogenic deposition (see the section “Series V–massive loams”) suggests that deposition of dust or mud by walking and trampling animals could be one of the accumulation processes.

The longest time interval is recorded by layer 4. Its deposition lasted for 4–5 thousand years according to the Bayesian model (Table 3). This interval corresponds to the late part of the Early Holocene and the entire Middle Holocene according to the formal stratigraphic subdivision of the Holocene[146]. It also corresponds to the entire Atlantic climatic chronozone[145]. Layer 3a from the entrance zone correlates with layer 4 according to the dating results and similarities in fossil rodent fauna, while the correlation between layers 3 and 4 is suggested by fossil rodent and mollusk fauna (see the sections “Malacological succession” and “Rodent succession”).

Layer 2 corresponds with Late Holocene. Poor chronometric data are available for layers 1-1a. However, assuming that the archaeological feature corresponding to PHA 4 cuts these layers and the lower boundary of PHA 4 was estimated to be 2.0–0.7 ky cal BP (Table 3), the accumulation of layers 1-1a started before that phase. This dating is in good agreement with the modeled boundary of layers 2 and 1a, which is 2.9–2.4 ky cal BP (Table 3).

Reliability of paleoenvironmental reconstruction.

The mollusk thanatocoenoses in caves represent well the diversity of habitats in the surroundings, comprising shells of species penetrating the cave, of those living on the surface near the cave entrance and the shells dropped from the surrounding rocks during sedimentation[147,148]. The rather good state of preservation of shells in ShSIII suggests that they did not undergo any intensive transportation but rather were accumulated in sediments in the primary place of deposition after the mollusk death.

The rodent remains were deposited mostly from pellets dropped by carnivorous birds, such as owls resting in a cave[7]. Rodents likely could have inhabited a range of habitats surrounding the cave, which had been used by the birds as their hunting territories. Therefore, rodents represent a wider area than mollusks. It is also expected that predatory birds prefer open habitats over canopy for use as hunting grounds[149,150], so as a consequence, the abundance of open-habitat rodents can be overrepresented in the fossil record.

Bats are unique among the fossil fauna, as they are troglophiles who live inside caves. Some of the recorded taxa are known to hibernate in caves[151], while the others use caves as their summer roosts[95]. Bats are also migrants and some species move between their winter and summer areas at the distance of over hundred kilometers. Thus, species who used the caves as their hibernacula do not represent the habitats surrounding the cave. This may be the case for M. dasycneme. This species is known to hibernate in caves[151], so its presence in ShSIII is possibly an effect of death during winter. The water bodies used by this species as hunting grounds[125,126] were located in its summer area, which could be far from the site.

Late pleistocene.

The oldest assemblages of mollusks and rodents (Vt and Dt, respectively) found in layers 7b-8-7a represent a rather poor fauna. Both assemblages are composed of species of cold climate, known from tundra and steppe biomes. Cold-tolerant snails Vallonia tenuilabris and Discus ruderatus indicate a cool continental climate and predominance of open habitats around the cave. The same habitats are preferred by lemmings. Dry open environments, i.e., steppe, are also indicated by the presence of C. cricetus and S. subtilis. However, some patches of cool, humid and shady habitats favorable for S. kotulae[83] also occurred, which indicates a mosaic of habitats. The rough and hilly topography of Kraków-Częstochowa Upland certainly was a factor favoriting the diversity of habitats. This is confirmed by regional paleobotanical data[152], which indicate that during Late Glacial of the Last Glaciation the clusters of trees dominated by pine, spruce and larch occurred beside the rocky slopes occupied by steppe-like communities.

The most informative is layer 8 with the highest number of shells. The occurrence of S. kotulae and D. ruderatus and lack of species typical of arctic climate, e.g., Pupilla loessica, Vertigo genesii and Vertigo geyeri, may indicate Bølling-Allerød interstadial[128,153]. Similar malacofaunas of this age are known from calcareous tufas and landslide deposits of southern Poland[34,37,153–155]. The rodent remains, though still low in number, follow the mollusk trend. They document higher abundance of woodland and humid environments during deposition of layer 8 in comparison to layers 7a and 7b. Additionally, the first appearance of a woodland species C. glareolus is recorded in layer 8.

Pleistocene-holocene transition.

Rich and diverse mollusk fauna of DrVc assemblage points to the beginning of the Holocene and amelioration of the climatic conditions compared to the Late Glacial. Radiocarbon dating of layers 6 and 5 from the central zone and 3a from the entrance zone indicate the Preboreal and Boreal phases of Early Holocene, and possibly the very beginning of the Atlantic phase [145]. The mollusk composition resembles the Ruderatus-fauna[156] known across Europe from many terrestrial sequences between the Preboreal and the older part of the Atlantic phase[14,16,77,79,128–130,153,157,158,159–163]. Expansion of shade-loving taxa, namely, Discus ruderatus, suggests growth of taiga-type coniferous forests, but some grasslands and sunny slopes preferred by Vallonia costata also occurred around the site. If shells have not been reworked, the environmental conditions in the beginning of Holocene favored the longer occurrence of glacial relics Semilimax kotulae and Vallonia tenuilabris. The last one was noted in Preboreal deposits in the nearby Cave above the Słupska Gate[41]. Gradual disappearance of glacial relics may correspond to gradual climate warming and some oceanic influences inferred from the first appearance of Sphyradium doliolum, Discus rotundatus, Aegopinella pura and other species of warm and humid conditions[41] (Fig 7).

The rodent assemblage CgLg found in layer 6 is still not abundant; however, it exhibits the highest Simpson index in the sequence. This reflects the high diversity of species and of habitats, as both the species of forest and of open landscape occur. Like in the case of snails, the rodent glacial relics survived, namely, Dicrostonyx torquatus and Lasiopodomys gregalis. According to Nadachowski[150], the glacial relics could survive in the region until the beginning of Late Holocene. Layer 6 is marked by the first appearance of M. subterraneus and genus Apodemus in the sequence. The first one was found in Late Glacial deposits of Shelter above the Niedostępna Cave[21,164], which is situated approximately 26 km away. In ShSIII this species is lacking in strata of that age and becomes abundant starting from layer 5 upward. This observation suggests reconsidering the early appearance of M. subterraneus in Shelter above the Niedostępna Cave, which could be an effect of postdepositional reworking. In another site with well-preserved Holocene deposits, Nad Mosurem Starym Duża Cave, its first appearance is even later, estimated to be ca. 4 ky BP[43].

Rodents of layer 5 record rapid improvement of environmental conditions. This is reflected by the increase of the remain number and higher amount of forest dwellers, such as C. glareolus, red squirrel Sciurus vulgaris and glirids Eliomys quercinus and Muscardinus avellanarius.

Interesting issue is a stratigraphic (and time) shift between the start of dominance of forest fauna in the mollusk and rodent records. The pick of forest-dwelling mollusks begins in layer 6 (or in layer 3a in the entrance zone), while in the case of rodents, only in layer 5 (or 3 in the entrance zone). This situation may be an effect of taphonomic biasing. As the accumulation of rodents prefers the taxa of open landscape (see the section “Reliability of paleoenvironmental reconstruction”), the dominance of forest rodents in the taphocenosis could have been intense since the forested area was virtually the only habitats in the surroundings, although patches of forest inhabited by forest rodents had been abundant earlier. The lack of chiropteran remains in the lower layers and their scarcity in layers 6 and 5 may be an effect of the unfavorable environmental conditions.

Holocene climatic optimum.

Predominance of mixed and deciduous forests around the cave during sedimentation of layers 5a, 4 and 3 is evidenced by DroAp mollusk assemblage, CgMs rodent assemblage, PaurMbra chiropteran assemblage and radiocarbon dating (9.5–4.5 ky BP). Discus ruderatus was replaced by more demanding D. rotundatus, D. perspectivus and other strictly forest species, e.g., A. pura, Balea biplicata, Ruthenica filograna and Isognomostoma isognomostomos (Fig 7). This records the progressive warming and was likely connected with transition from continental to oceanic circulation across Central Europe and the climatic optimum of the Holocene–the Atlantic phase[77,129,130,159,163,165–167]. These data are in agreement with floristic changes in Central Europe[168,169]. The climatic optimum is indicated by the presence of Vestia elata, which has narrow ecological tolerance and favors warm and humid conditions. This snail has been described from Atlantic phase at other sites in the region and disappeared during the Subboreal phase[11,12,170]. Today, only limited relict sites with this species are noted in Poland in the Beskidy, Bieszczady and the Holy Cross Mountains[171].

The composition of rodent taphocenosis in layers 5a, 4 and 3 is similar to that in layer 5. All these layers are characterized by the highest richness of taxa (Fig 8). The important difference in comparison to layer 5 is much higher number of remains. Simpson index of diversity is lower than in most of other layers, which is a result of strong predominance of two species, C. glareolus and M. subterraneus, both typical for woodlands.

The chiropteran assemblage PaurMbra, found in these layers, is also among of the richest in the sequence, both in terms of number of taxa and number of remains. The thanatocoenosis is characterized by taxa which prefer cold caves as their hibernacula, with temperature below 6°C (which stays in accordance with small size of the ShSIII and testifies that the shelter already had than a similar size to the modern one), and big trees as summer roosts (B. barbastellus, M. bechsteinii and P. auritus). This suggests the presence of old-growth forest with sparse open areas (because of the presence of Eptesicus serotinus). The occurrence of Rhinolophus hipposideros, a species that typically prefers warmer caves to hibernate, could be limited to the summer period.

Post-optimum deterioration of habitats.

Starting from approximately 5 ky BP, the malacofauna of ShSIII is dominated by mesophilous species. The forest malacofauna is still diverse but significantly outnumbered, mostly by Laciniaria plicata (Fig 7). The overall tendency of an increasing number of gastropods of wide ecological tolerance in costs of shade-loving taxa suggests a gradual deforestation and exposure of rocky walls around the cave. A similar situation is recorded in other Subboreal and Subatlantic sequences from caves and rockshelters of Central Europe[14,16,35,36,41,163].

The upper part of the sequence is characterized by a high abundance of edible dormouse Glis glis, which is the third most numerous rodent species in layers 2 and 1a. Its abundance probably coincided with a change in forest cover around the cave and rise in mature beech forest, which is a preferred habitat of this species[102,114]. Beech forest also constitutes the main type of the recent natural vegetation in the microregion. The expansion of this tree into the region was quite late, the beech forests appeared here approximately 3.5 ky BP[172]. This dating corresponds well with the presumed chronology of the mentioned layers.

The uppermost layers 1 and 1a record also the first appearance of M. arvalis and Micromys minutus. The arrival of both these species was most likely of synanthropic character, as they prefer artificial landscapes (agricultural fields and meadows). A similar observation of the appearance of M. arvalis during the late part of Late Holocene was noticed from other sites in the region[150]. Particularly, the Holocene profile of Nad Mosurem Starym Duża Cave shows the same pattern of rodent succession[43]. The presence of single remains of tundra species (Dicrostonyx torquatus) in layer 1a may be an effect of post-depositional disturbances.

Chiropteran fauna notes decline in richness and number of specimens, following the trend in mollusks and rodents. There is a clear predominance of taxa foraging in wooded areas (i.e., B. barbastellus, M. bechsteinii, P. auratus and M. brandtii). The presence of M. myotis can be related to a lack of undergrowth in the surrounding forest, while M. mystacinus, M. nattereri, M. emarginatus and P. austriacus suggest the presence of open and/or diversified areas, too. All these data likely indicate deterioration of habitats, most likely of anthropogenic origin.