10.6092/issn.1973-9494/7118
I fenomeni di biodeterioramento causati da condizioni ambientali favorevoli, come infiltrazioni di acqua piovana, fenomeni di condensazione e abbondanza di sali e nutrienti organici, sono di grande importanza negli insediamenti rupestri. Il rifugio Rinaldi, all’interno di un habitat forestale naturale a querceto misto presente nella località di Filiano, rappresenta un sito di particolare importanza per la presenza di pitture preistoriche. Il sito costituisce un caso emblematico del delicato equilibrio raggiunto attraverso i secoli, tra ambiente e opera d’arte. Sono oggi visibili le tracce del collasso di parte della volta che copriva il rifugio e i segni di annerimento causati dai fuochi degli antichi insediamenti. Sono stati già individuati molti dei biodeteriogeni tipici dell’habitat roccioso, come alghe, cianobatteri, funghi, licheni, muschi e piante vascolari, che formano comunità individuabili macroscopicamente. Ogni comunità ha una propria preferenza ecologica e la mappatura della loro distribuzione è uno strumento utile per capire le variazioni dei fattori ambientali maggiormente incidenti. Applicando le informazioni ecologiche alla caratterizzazione tassonomica delle specie e alla distribuzione spaziale di ogni comunità, è stata costruita una mappatura dell’umidità e della presenza di nutrienti nel sito. Fra le varie comunità, i funghimicrocoloniali (MCF), che appaiono come piccoli spot neri, rappresentano il maggior fattore di rischio del sito a causa del loro scarso bisogno d’acqua. È stata effettuata anche una valutazione del rischio biologico legato alla loro presenza, suggerendo delle misure di mitigazione indiretta tramite la modificazione del microclima e delle condizioni di ventilazione locali.
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1973-9494
7118
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Ornella Salvadori
Conservation Science in Cultural Heritage
water mapping
Ecological Mapping for the Preventive Conservation of Prehistoric Mural Paintings in Rock Habitats: the Site of Filiano (Basilicata, Italy)
Text.Serial.Journal
https://conservation-science.unibo.it/
15
Articles
2017-06-01
2017-07-04
2017-06-01
2017-09-04
53-59
CSCH
Ornella Salvadori
2015
10.6092/issn.1973-9494/7118
53
Lab. Scientifico Polo Museale Veneziano
1973-9494
2
water mapping
en
59
Ecological Mapping for the Preventive Conservation of Prehistoric Mural Paintings in Rock Habitats: the Site of Filiano (Basilicata, Italy)
https://conservation-science.unibo.it/article/download/7118/6828
15
E    COLOGICAL MAPPING FOR THE PREVENTIVE CONSER-
     VATION OF PREHISTORIC MURAL PAINTINGS IN ROCK
     HABITATS: THE SITE OF FILIANO (BASILICATA, ITALY)

   Giulia Caneva*, Marco Tescari, Flavia Bartoli 4
   Dip. Scienze, Università degli Studi Roma Tre, Viale Marconi 446, Roma, Italia
   Maria Pia Nugari, Anna Maria Pietrini
   Istituto Superiore Conservazione e Restauro, Via di San Michele 22, Roma, Italia
   Ornella Salvadori
   Lab. Scientifico Polo Museale Veneziano, Cannaregio 3553, Venezia, Italia

   Keywords: mural paintings, biodeterioration ecology, rock settlements, water mapping


   1. Introduction

    The conservation of mural paintings in rocky habitats may be affected by several
environmental factors, such as infiltrations of rainwater, condensation, presence of
salts [1]. These phenomena are also linked to the use of caves as human and animal
shelters and to their close contact with soil, often enriched with organic nutrients, etc.
[2]. It is in these conditions that biodeterioration phenomena frequently occur. Photo-
synthesising organisms prevail when lighting conditions are sufficient, but colonization
due to heterotrophic organisms becomes more evident when enrichment of organic
material occurs [3].
    The literature gives more or less detailed information on the prevalent taxonomic




                                                                                                  CONSERVATION SCIENCE IN CULTURAL HERITAGE
composition of such communities. However, little information exists on the ecology
of the different biodeterioration patterns, but is nevertheless important for preventive
and long-lasting conservation. In fact, such knowledge can help in assessing the best
environmental conditions to be maintained and those to be avoided [4].
    Rinaldi’s shelter in Filiano, which is of high value due to the significant traces of
Palaeolithic age paintings, is an emblematic case of the delicate balance, achieved
throughout the centuries, between the environment and artwork.
    The aim of this study is to analyse the ecological aspect of such biodeterioration
phenomena, in order to contribute to the correct planning of conservation activities.

   2. Study area

  Rinaldi’s shelter is located in Filiano, in the anthropological reserve in the Southern
Apennine hilly belt (Basilicata, Italy). The reserve is characterized by a dense forest
canopy with a predominance of turkey oak (Quercus cerris), together with other decid-
uous species, such as Carpinus betulus, Fraxinus ornus, Q. pubescens, Q. frainetto,
Acer pseudoplatanus probably already present at the time of the settlement.



* Corresponding author: giulia.caneva@uniroma3.it

                                                                                             53
                                                                                                                     The prehistoric paintings, made with pigments identified as red ochre based on
                                                                                                                  haematite, were executed following the oldest kind of parietal art technique, which con-
                                                                                                                  sisted in laying the colours directly on the rock walls without any previous plastering.
                                                                                                                     The anthropic use of the shelter is evident from the diffuse blackening of carbona-
                                                                                                                  ceous matter mixed with sulphur, probably due to fire traces. Moreover a widespread
                                                                                                                  presence of phosphate and calcium oxalate can be related to the accumulation of
Caneva, Tescari, Bartoli, Nugari, Pietrini, Salvadori - ECOLOGICAL MAPPING FOR THE PREVENTIVE CONSERVATION




                                                                                                                  bird’s guano and of grazing animals’ excrements. The occurrence of widespread con-
                                                                                                                  cretionary layers appears as the result of dissolution and re-crystallization cycles of the
                                                                                                                  carbonaceous sandstone cement triggered by water permeating into the sediment [5].
                                                                                                                     During the multi-millennial history of the site, a part of the ceiling made of calcare-
                                                                                                                  ous sandstone collapsed, reducing the functions of the shelter and exposing the pic-
                                                                                                                  tures to more aggressive environmental conditions.
                                                                                                                     Macroclimatic conditions changed during this period, with cycles of warm and cold
                                                                                                                  periods.
                                                                                                                     Today, the average annual temperature is around 12.5°C; February is the coldest
                                                                                                                  month, with 3.1°C and August is the warmest with 21.0°C. Often during the winter
                                                                                                                  season below-zero values are registered, which can lead to the formation of ice that
                                                                                                                  favours the rise of fractures in the lithic substrate. The average annual rainfall is around
                                                                                                                  684.3 mm, with a high concentration in autumn and winter and the lowest values in
                                                                                                                  summer, the typical trend of a Mediterranean bioclimate. The prevailing winds come
                                                                                                                  from the Western quadrants and those associated with rain come from the Eastern and
                                                                                                                  Western quadrants.




                                                                                                                               Figure 1. Rinaldi’s shelter and the dense forest cover surrounding it.



                                                                                                                     3. Methodology

                                                                                                                      In order to investigate the nature of the biodeterioration phenomena, various sam-
                                                                                                                  ples of the main alterations observed in situ were collected. In the case of phototro-
                                                                                                                  phic microflora, taxonomic characterization was carried out by observation, under
                                                                                                                  optical microscope, of the morpho-anatomic features of microorganisms and cultural
                                                                                                                  analyses, as described in a previous study [2]. For lichens and vascular plants, iden-
                                                                                                                  tification was carried out following the usual analytical characters by microscopy
                                                                                                                  observation.
                                                                                                                      In the case of endolithic growth forms, polished cross sections were prepared in
                                                                                                                  order to observe and measure the possible deep penetration of the organisms.


                                                                                                             54
    After identification of the communities, their distribution was also determined
through surveys in the field and photographs. Ecological evaluation of the differ-
ent biodeterioration patterns was then carried out by accessing different data bases
[6-8]. The data of the biodeterioration pattern distribution were used to highlight the
gradient of the most relevant limiting factor. The distribution of the community was
also used to calculate the risk of stone damage relating to each community by taking
into consideration structural and physiological characteristics, as referred from the
literature.

  4. Results

    The distribution of the different weathering patterns observed in such rich environ-
ments seems mostly linked to the gradients of water and its variations (Figure 2b).
Light, that is highly relevant for photosynthesising organisms, seems here to have a
secondary role. The forest favours the sciaphylous species, but light is not a limiting
factor. The most hygrophylous species are clearly mosses and ferns, concentrated
along the percolation lines. The lichen cover, such as the green algae, is also favoured
by high humidity. Cyanobacteria prevail in the xeric conditions. The most xerophy-
lous species are however the microcolonial fungi (MCF) penetrating into the substrate,
whose growth is also favoured by the enrichment of nutrients typical of the forest habi-
tat. They probably also cause the high spread of calcium oxalate patinas in different
areas of the rocks.
    The major part of the deterioration phenomena detected in the area close to the
shelter are, however, not linked to the development of photosynthetic microflora. The
few species found belong to a community of cyanobacteria (Chroococcus lithophilous,
Gloeocapsa sanguinea, Calothrix parietina e Lyngbya sp.) and of eukaryotic microal-
gae (Pleurococcus vulgaris e Muriella terrestris), ubiquitarian components of the mi-
crobial communities which develop over ground or rock surfaces.




                                                                                                  CONSERVATION SCIENCE IN CULTURAL HERITAGE
    The development of black meristematic fungi, as a most xerotolerant microflora,
is detectable as little superficial black spots, in some areas near the paintings. Such
fungal species are frequently found on lithic materials exposed to the open air in hostile
environmental conditions [9].

  5. Conservative interventions

   The presence of black meristematic fungi close to the painted area is the most criti-
cal phenomenon for conservation of the paintings. Special attention, however, should
be given to the presence of vascular plants which can be found in the narrower areas
(Figure 2a). In fact, the roots of the plants tend to penetrate through the part with less
resistance, giving way to the breaking of rocks. Some species, such as Quercus cerris
and Fraxinus ornus show, in general, a high level of potential aggressiveness, but for
the moment this risk is not highly relevant. On the contrary, the neighbouring forest
covering seems to exert a protective effect from the erosion caused by the prevailing
winds and the effects of sun radiation.
   It can be hypothesized that in the prehistoric age some kind of biological coloniza-
tion may already have taken place, but the high level of dryness in the vertical and
sheltered areas prevented its biological development.



                                                                                             55
Caneva, Tescari, Bartoli, Nugari, Pietrini, Salvadori - ECOLOGICAL MAPPING FOR THE PREVENTIVE CONSERVATION




                                                                                                                  Figure 2. (a) Several biodeterioration patterns and other weathering forms: the red areas
                                                                                                                  correspond to the most dangerous colonization, due to lichens and higher plants; the violet
                                                                                                                  areas correspond to the highest algal growth, and the dark violet areas show an accumulation
                                                                                                                  of carbonaceous particles. (b) Water mapping according to a blue-gray gradient: mosses and
                                                                                                                  ferns in areas with the highest water input, followed by lichens, green algae, cyanobacteria and
                                                                                                                  microcolonial fungi.

                                                                                                                     Today, due to the fragile balance of the shelter, and in spite of some limited protec-
                                                                                                                  tion, it has nevertheless partially collapsed. It would be advisable to intervene with
                                                                                                                  extreme caution in changing such ecological conditions, acting especially on improving
                                                                                                                  seepage of watercourses near the painted area by diverting them away from the mass
                                                                                                                  of stone. This intervention will have to be carried out above the shelter, by altering the
                                                                                                                  flow of water.
                                                                                                                     Building a cover which could further remove the risk of water seepage during rain
                                                                                                                  phenomena has to be studied carefully and should avoid excessively modifying exist-
                                                                                                                  ing microclimatic conditions, which could cause the formation of micro air currents and
                                                                                                                  possibly give rise to evaporation phenomena.
                                                                                                                     On the other hand, a protective covering from the rain could be an effective barrier
                                                                                                                  from chemical and biological weathering processes which could interfere with the en-
                                                                                                                  dolithic growth already established on the site.

                                                                                                                     6. Conclusions

                                                                                                                     Taking into account biological components in rocky habitats, an ecological ap-
                                                                                                                  proach, which considers the micro-climatic conditions and the diversity of biodeteriora-
                                                                                                                  tion patterns, plays a central role in preventive conservation.



                                                                                                             56
   A forward-looking risk assessment is necessary in the case of a complex and impor-
tant site such as Filiano. The ecological mapping, which considers the biodeterioration
pattern distribution according to the gradient of the limiting factors, is a powerful tool for
the analysis of site conditions. When biological colonization is relevant, a map based on
the ecological characteristics of species must form the core of any conservation plan.


      Aknowledgments

      This work was supported by grants from the Zetema foundation (Matera).


      References

[1]     Caneva G., Nugari M.P., Salvadori O., (2008) Plant Biology for cultural heritage.
        Los Angeles: Getty Conservation Institute.
[2]     Caneva G., Nugari M.P., Pietrini A.M., Salvadori O., Tufano M., Lombardozzi V.,
        (2010) Biodeterioration problems of mural paintings in rock habitat: the prehis-
        toric site of Filiano (Basilicata, Italy). In: Ferrari et al. (eds.), Science and Technol-
        ogy for the Safeguard of Cultural Heritage in the Mediterranean Basin, 4th Int.
        Congress, Cairo, 2009, vol. II, pp. 95-98.
[3]     Nugari, M.P., Ricci, S., Roccardi, A., Monte, M., (1998) Chiese ed Ipogei, in Man-
        drioli P., Caneva G. (eds.), Aerobiologia e beni culturali, Nardini, Fiesole, pp.
        229-246.
[4]     Caneva, G., Bartoli, F., Ceschin, S., Salvadori, O., Futagami, Y., Salvati, L.,
        (2015) Exploring ecological relationships in the biodeterioration patterns of An-
        gkor temples (Cambodia) along a forest canopy gradient, Journal of Cultural
        Heritage, 16(5), pp. 728-735.




                                                                                                          CONSERVATION SCIENCE IN CULTURAL HERITAGE
[5]     Giovagnoli, A., Paradisi, A., Polidoro, A., Ricci, M.A., Santonico, G., Sodo, A.,
        (2010) Alteration and decay study of a rock painting in outdoor exposure. The
        “Riparo di Tuppo dei Sassi” at Filiano (PZ), in Ferrari et al. (eds.), Science and
        Technology for the Safeguard of Cultural Heritage in the Mediterranean Basin,
        4th Int. Congress, Cairo, (2009) vol. II, pp. 99-102.
[6]     Nimis, P.L., (1987) I macrolicheni d’Italia: chiavi analitiche per la determinazione,
        Museo friulano di storia naturale.
[7]     Guiry,M.D. & Guiry, G.M., (2015) AlgaeBase, World-wide electronic publication,
        National University of Ireland, Galway, http://www.algaebase.org.
[8]     Ellenberg, H., (1988) Vegetation Ecology of Central Europe, 4th Ed. Cambridge:
        Cambridge University Press.
[9]     Onofri, S., Zucconi, L., Isola, D., Selbmann, L., (2014) Rock-inhabiting fungi and
        their role in deterioration of stone monuments in the Mediterranean area, Plant
        Biosystem, 148, pp. 384-391.

      Biographical notes

  Giulia Caneva, full professor of Botany and Vegetation ecology c/o Science Depart-
ment of Roma Tre University, Director of the University Centre for Studies of Rome
(CROMA). Coordinator of the Applied Botany group of Società Botanica Italiana (SBI)


                                                                                                     57
                                                                                                                  and Ordine Nazionale Biologi (ONB) member of the Cultural Heritage Committee. Au-
                                                                                                                  thor of several publications and monographs on the conservation of works of art.
                                                                                                                      Maria Pia Nugari, biologist and former Director of the Scientific Laboratory of the
                                                                                                                  Istituto Superiore per la Conservazione ed il Restauro (MiBact). Author of monographs
                                                                                                                  and numerous scientific publications on the biodeterioration of art works.
Caneva, Tescari, Bartoli, Nugari, Pietrini, Salvadori - ECOLOGICAL MAPPING FOR THE PREVENTIVE CONSERVATION




                                                                                                                     Anna Maria Pietrini, biologist and Director of the Phycology Area, Biology Labora-
                                                                                                                  tory of the Istituto Superiore per la Conservazione ed il Restauro (MiBact). Author of
                                                                                                                  numerous scientific publications on the biodeterioration of stone.
                                                                                                                     Marco Tescari, degree in “Genetics and Molecular Biology” at the University “La
                                                                                                                  Sapienza” of Rome; PhD student at the Univ. “Roma Tre”, dealing with the characteri-
                                                                                                                  zation of biodeteriogens microorganisms of stone monuments.
                                                                                                                      Flavia Bartoli, degree in “Ecosystems Management and Biodiversity” at the Univer-
                                                                                                                  sity “Roma Tre”, PhD on the conservation of cultural heritage by biological colonization.
                                                                                                                     Ornella Salvadori, biologist, Director of Lab. Scientifico Polo Museale Veneziano.
                                                                                                                  Author of monographs and numerous scientific publications on the biodeterioration of
                                                                                                                  art works.




                                                                                                             58
    Summary
    Biodeterioration phenomena are of great relevance in rock settlements, due to fa-
vourable environmental conditions, such as the infiltration of rainwaters, condensation
phenomena and abundance of salts and organic nutrients. Rinaldi’s rock shelter in
Filiano, which is located in a natural forest of mixed oaks is of great value due to the im-
portant traces of prehistoric paintings. It is an emblematic case of the delicate balance,
achieved throughout the centuries, between the environment and artwork. During the
plurimillenarian history of the site, a portion of the ceiling that covered the shelter col-
lapsed, leaving signs that are still visible today, together with traces of blackening left
by the fires of ancient settlements. Several of the biodeteriogens typical of rocky habi-
tats have already been detected and include algae, cyanobacteria, mosses, lichens,
vascular plants and fungi, which form macroscopic communities.
    Each community has an ecological preference and the mapping of their distribution
is a suitable tool for understanding variations in the environmental factors that most
affect them. Relating ecological data to the taxonomical characterization of the species
and to the spatial distribution of each community, a site map of the humidity and of the
nutrients was obtained. Among the various communities, microcolonial fungi (MCF),
which appear as little black spots, here, represent the most critical risk factor, due to
their low water needs. An evaluation of the biological risk for the possible future attack
of such a biological community was made, suggesting indirect mitigation measures,
through modification of the microclimatic and local ventilation conditions.


    Riassunto
    I fenomeni di biodeterioramento causati da condizioni ambientali favorevoli, come
infiltrazioni di acqua piovana, fenomeni di condensazione e abbondanza di sali e nu-
trienti organici, sono di grande importanza negli insediamenti rupestri. Il rifugio Rinaldi,
all’interno di un habitat forestale naturale a querceto misto presente nella località di Fi-




                                                                                                     CONSERVATION SCIENCE IN CULTURAL HERITAGE
liano, rappresenta un sito di particolare importanza per la presenza di pitture preistori-
che. Il sito costituisce un caso emblematico del delicato equilibrio raggiunto attraverso
i secoli, tra ambiente e opera d’arte. Sono oggi visibili le tracce del collasso di parte
della volta che copriva il rifugio e i segni di annerimento causati dai fuochi degli antichi
insediamenti. Sono stati già individuati molti dei biodeteriogeni tipici dell’habitat roccio-
so, come alghe, cianobatteri, funghi, licheni, muschi e piante vascolari, che formano
comunità individuabili macroscopicamente. Ogni comunità ha una propria preferen-
za ecologica e la mappatura della loro distribuzione è uno strumento utile per capire
le variazioni dei fattori ambientali maggiormente incidenti. Applicando le informazioni
ecologiche alla caratterizzazione tassonomica delle specie e alla distribuzione spa-
ziale di ogni comunità, è stata costruita una mappatura dell’umidità e della presenza
di nutrienti nel sito. Fra le varie comunità, i funghimicrocoloniali (MCF), che appaiono
come piccoli spot neri, rappresentano il maggior fattore di rischio del sito a causa del
loro scarso bisogno d’acqua. È stata effettuata anche una valutazione del rischio biolo-
gico legato alla loro presenza, suggerendo delle misure di mitigazione indiretta tramite
la modificazione del microclima e delle condizioni di ventilazione locali.




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