Pollen analyses of Pleistocene hyaena coprolites from Montenegro and Serbia

The results of pollen analyses of hyaena coprolites from the Early Pleistocene cave of Trlica in northern Montenegro and the Late Pleistocene cave of Baranica in southeast Serbia are described. The Early Pleistocene Pachycrocuta brevirostris, and the Late Pleistocene Crocuta spelaea are coprolite-producing species. Although the pollen concentration was rather low, the presented analyses add considerably to the much-needed knowledge of the vegetation of the central Balkans during the Pleistocene. Pollen extracted from a coprolite from the Baranica cave indicates an open landscape with the presence of steppe taxa, which is in accordance with the recorded conditions and faunal remains. Pollen analysis of the Early Pleistocene samples from Trlica indicate fresh and temperate humid climatic conditions, as well as the co-existence of several biotopes which formed a mosaic landscape in the vicinity of the cave.


Introduction
Pleistocene pollen data from the central Balkans are very scanty (JANKOVI] et al. 1984; NIKOLI] 1992).The Early Holocene is somewhat better covered.Data on the history of Postglacial vegetation come from the Vlasina peat-bog in south-eastern Serbia (^ERNJAVSKI, 1938) and the Jelica Mountain in western Serbia ([ER-CELJ & CULIBERG 1992).Important information about the Early Holocene vegetation comes from the Vlasac archaeological site found in the Iron Gates sector of the Danube Gorge.It is a Lepenski Vir culture site, excavated in the 1970s (GARA [ANIN 1978;SREJOVI] & LETICA 1978).Pollen analysis has been performed on human coprolites (CARCIUMARU 1978), and gave a rather large number of pollen grains.Findings of copro-lites at Pleistocene sites in Montenegro and Serbia gave hope about the potential of palynology in these food stuffs, and provide previously missing data concerning the vegetation.

Localities
Baranica.It is a cave in eastern Serbia, situated on the right bank of the Trgovi{ki Timok River, approximately 5 km south-east of the town Knja`evac.It is a composite cave consisting of many narrow cave passages.There are several entrances into the cave system; one positioned 15 m above the river bed (260 m altitude) opens into an entrance chamber 5 m wide.This part of the cave is named Baranica I.The other entrance is located about 20 m above the first (280 m-asl), and is named Baranica II.
Archaeological excavations were first performed in 1994 in Baranica I.The site became renowned because many bones were found that "looked like" bone implements, which were later recognized in further research as hyaena-made.Nevertheless, archaeological implements were found during the continuation of the excavations between 1995 and 1997.Upper Palaeolithic artifacts were found in Baranica I (MIHAILOVI] et al. 1997) and numerous faunal remains in both Baranica I and Baranica II (DIMITRIJEVI] 1997(DIMITRIJEVI] , 1998)).
The accumulation of faunal remains is mostly due to the scavenger activity of cave hyenas (DIMITRIJEVI] 2004), which produced a very rich vertebrate assemblage.The list of large mammals found gives a good representation of the fauna in the region at this period, with more taxa being found than in any other cave locality in Serbia (Table 1).The regional importance of Baranica is accentuated by the fact that it is the first locality in the region with fauna reflecting the conditions of the Last Glacial Maximum.As opposed to other excavated sites in Serbia, Baranica also shows cold fauna, including the wolverine, Gulo gulo and the wooly rhino, Coelodonta antiquitatis.It is also worth stressing the absence of warm temperate species such as the roe deer and the wild boar.
Besides large mammal bones, remains of small mammals, birds, herpetofauna and fish are also found.Nineteen species of rodents have been identified (Table 2).Similar to large mammals, the small mammal remains indicate the cold conditions of the Last Glacial period, especially boreal and arctic species such as Microtus gregalis and Dicrostonyx (BOGI]EVI] 2005).
Trlica.It is a karstic cavern which opens at 770 masl in Triassic limestones, located on the slope of the so-called Trlica Hill, near the city of Pljevlja in northern Montenegro.The Trlica Hill surmounts a Tertiary coal basin and the valley of the ]ehotina River.Palaeontological excavations were performed in three short campaigns (1988, 1990, and 2001).Abundant remains of mammals were found embedded in clastic deposits infilling the karstic cavern (Table 3)

Samples
Two coprolites, one from the Baranica Cave, and another one from the site of Trlica were extracted for pollen analysis in 2004.The number of pollen grains was low, especially in the Trlica sample.For this reason, five more coprolites were analysed in 2005, which gave better results (Fig. 1).Their dimensions and mass are given in Table 4.
By their shape, dimensions and texture, all specimens resemble hyena coprolites, especially those specimens from Trlica which are complete.The specimen from Baranica is a broken half, showing a compact structure and homogeneous composition on the breakage, which is essentially calcium phosphate originating from the bones consumed by this animal.It is known that pollen is incorporated into coprolites in different ways: absorbed with food (meat and stomach contents of the prey), with water, by the licking of fur or paws and, in some cases, even by ingesting vegetable matter.Taphonomic observations on fresh hyaena dung show that the pollen spectra obtained from coprolites gave relatively unbiased pictures of the landscape (SCOTT et al. 2003).Thus, fossil coprolites can provide available palaeoenvironmental information (LEROI-GOURHAN 1966;MOE 1983;SCOTT 1987;ARGANT 1990ARGANT , 2004;;CARRIÓN et al. 2001;YLL et al. 2006).As they generally correspond to a very short period of time, they should also be indicators of the season when the coprolites were produced (ARGANT 1990(ARGANT , 2004;;TOMESCU 2006).
According to the faunal list from the two localities, these coprolites might originate from two different hyena species, Early Pleistocene Pachycrocuta brevirostris, and Late Pleistocene Crocuta spelaea (ERXLE-BEN).Even if the feeding habits of these two species could slightly differ, the chemical composition and morphology of their coprolites look similar.Their life habits and territorial range should be reasonably similar to those of the recent species Crocuta crocuta, mostly a scavenger.Since it is considered that members of the latest species cover a territory with-

Sample preparation
The surface was first very precisely cleaned, by intensive brushing under a jet of water, in order to remove potentially polluted material and to ensure that only the content of the coprolite was treated.
The content of the coprolite was then prepared by concentration in a dense liquid, comprising the following principal stages: • Decarbonatation with hydrochloric acid, desilicification with hydrofluoric acid (concentration 40%, cold test).
• Removal of the organic matter by heating in potassium hydroxide solution for 10 minutes.
• Washing out with distilled water after each operation.

Results of the pollen analysis, Baranica II Cave (Table 5)
The sample from the Baranica Cave came from half of the coprolite (inventory number BAR II 97/12/3).
Altogether it yielded 13 pollen grains and only 7 taxons.Trees were mostly represented by Pinus and Juniperus, both genera heliophilous and pioneers.A single deciduous tree was present: Fraxinus, a tree demanding moist soil and good exposure to sunlight.Its presence most probably depicting a gallery forest.Among herbs, the genus Artemisia was the best represented.It was accompanied by an Asteraceae of the Carduus type, one Poaceae and one pollen grain of Scrophulariaceae.
According to these results, it is obviously not possible to precisely reconstruct the past vegetation.Yet, some information can be given: a very open landscape with the presence of steppe taxa related to rather rigorous climatic conditions.Together with the fauna, this is in accor-dance with the conditions of the Last Glacial.It is not possible to be more precise because of the small number of pollen grains and the isolated character of the sample.

Results of the pollen analysis, Trlica Cave (Table 5, Fig. 2)
Only three pollen grains were extracted out of the first sample from Trlica, (TRL 90/1021), two originating from trees, and one from grass.Nevertheless, even this small number of pollen grains showed the absence of a steppe environment.Quercus and Corylus are mesothermophilous trees, demanding temperate and humid conditions.
Due to the small number of grains in this sample, five more coprolites were analysed.All of them were completely searched under the microscope.
All of the latter were very well preserved, and in some of them the cell structure is still observable.Fifteen different taxons were identified.Tree pollen grains dominated with 40 grains out of the total of 56.Although the sum of pollen grains was not sufficient to calculate percentages, they were sufficient to suggest that wooded areas existed in the animal habitat, and that they occupied an important portion of the region.
A quarter of the tree pollen grains originated from alder (Alnus), a tree demanding soil humidity.The animal probably visited an alder forest and, consequently a field in the vicinity of a stream and/or a swamp.This was confirmed by observing moss fibres together with 18 spores of Sphagnum cf.fallax, a species which is characteristic of swampy fields, peat bogs, alder fields or humid and sour prairies (JAHNS 1989).Sphagnum spores do not disperse widely; consequently in this case they could have been absorbed by an animal only at the place at which they developed.Some of them were still sealed in an organic fibrous matter (Fig. 2), which could originate only from swampy alder terrains.A humid environment where animals were coming to drink is also illustrated by a tetrad of club grass (Typha latifolia), a species which grows on low elevations, and, in this case, was probably not very far from the cave.Birch undoubtedly represented a part of this humid formation.Oak (Quercus) and hazel (Corylus) seem to have been quite abundant.Hornbeam (Carpinus) and ground box (Buxus) were also observed, which can grow in low humid places, but also on more arid slopes, while on higher elevations there were fir (Abies) and beech (Fagus), although, the presence of fir and beech in a valley cannot be excluded.Finally, the presence of Juniperus, heliophilous taxon signalling the presence of openings in the tree cover occupied also by grasses (Poaceae, plantain) and Calluna ( Ericacae), was also registered.The complete pollen content from the coprolites of Trlica enables a tentative reconstruction of the environment in which the Trlica fauna existed.A summary of this reconstruction is given in Fig. 2, illustrating a possible distribution of the identified vegetation, as well as providing photographs of some of the pollen grains extracted from the coprolite TRL 90/80/2.
The reconstruction is, of course, hypothetical, and should be taken with caution.The coexistence of several biotopes is suggested, forming a mosaic landscape where trees occupied an important place.At the bottom of the valley, the humid bank of a stream or a pond was mostly occupied by alder, at the foot of which a moss (Sphagnum) carpet had developed.Mesothermophilous trees (oak, hornbeam, hazelnut), as well as shrubs (juniper, ground box and broom) were growing on the slopes, while at higher levels there were firbeech forests.Throughout this area, open spaces were interspersed.The observed combination of species indicates temperate climatic conditions, fresh and humid, which enabled development of different biotopes dependent on the altitude and on edaphic conditions.

Conclusion
The number of pollen grains extracted from the coprolites from the two cave localities, Late Pleistocene Baranica in Serbia and Early Pleistocene Trlica in Montenegro, was rather low and gave only modest possibilities for the reconstruction of the vegetation milieu of the surroundings of the two caves.Yet, for those two localities, coprolite analyses gave the only data on the vegetation.This may also be the case for other cave localities in which coprolites are found, since cave sediments are often unsuitable for fossilisation of plant remains, and pollen grains particularly.Since it is well known that important faunal remains, sometimes only available for certain regions or time spans, are often related to caves, the instances of pollen preservation in coprolites are even more valuable.Pollen is not always present in coprolites but encompassed in their mass, pollen grains are sometimes safe from digestive processes and oxygen impact and are, therefore, well preserved.When coprolites are numerous, and their stratigraphical position well-defined, they should be regarded as important for pollen sampling.On the basis of the analyses of pollen extracted from the coprolite from the Baranica Cave an open landscape with the presence of steppe taxons related to rather rigorous climatic conditions is assumed, which is in accordance with the conditions of the Last Glacial and faunal remains recorded.The pollen content from the coprolites of Trlica enabled a tentative reconstruction of the environment.Temperate climatic conditions were indicated, fresh and humid, as well as the co-existence of several biotopes which formed a mosaic landscape, depending on the altitude and edaphic conditions.
in a distance up to 4 km(ARGANT 2004), the pollen analyses from coprolites are expected to give data on climatic and edaphic conditions in the near vicinity of the sites.

Table 1 .
List of the large mammals found in the caves Baranica I and II, Late Pleistocene, eastern Serbia.

Table 2 .
List of the rodent fauna found in the caves Baranica I and II, Late Pleistocene, eastern Serbia.

Table 3 .
List of the mammal fauna found in the Trlica Cave, Early Pleistocene, Montenegro.

Table 4 .
Dimensions and masses of the coprolites from Trlica, Early Pleistocene, Montenegro.* measurement was impossible because the coprolite was broken

Table 5 .
Content of pollen and spores from the Late Pleistocene Crocuta spelaea coprolite from Baranica II Cave, and Early Pleistocene Pachycrocuta brevirostris coprolites from the Trlica Cave.AP, arboreal pollen; NAP, nonboreal pollen.