Prehistoric Sites and Decorated Caves of the Vézère Valley

Outbreaks of mould and bacterial spores on the surface of the cave paintings of Lascaux resulting from bio-climatic imbalance in the cave

At its 32nd session (Quebec City, 2008) the World Heritage Committee expressed its concern that a new microbial outbreak in the cave in 2007 could not be prevented. While noting the work being undertaken to address the situation, the World Heritage Committee nevertheless urged the State Party to strictly limit access to the cave; isolate the hill of Lascaux and to monitor any potential impacts including waterflows; strengthen the International Scientific Committee for Lascaux Cave, through the inclusion of appropriate specialists in the fields of conservation and prehistory;  carry out an impact study on any further intervention including chemical and mechanical treatments to the paintings; and to continue its communication work to ensure full information on all conservation activities. The World Heritage Committee also encouraged the State Party to make available to interested States Parties the report of the International Scientific Committee. The World Heritage Committee further requested the State Party to invite a joint World Heritage Centre / Advisory Bodies mission to examine the overall state of conservation of the property, and in particular the specific threats to the Lascaux cave paintings; and suggested that in the absence of substantial progress in finding out the causes of and treatment for the damage to the art, the inscription of the property on the List of World Heritage in Danger should be considered at the next session.

On 30 January 2009, the State Party submitted the state of conservation report on the property. This provided progress on the isolation of the hill, the structure of the International Scientific Committee and the conservation work.

a) International Scientific Committee

On the structure of the International Scientific Committee it is stated that its mandate, which expires in June 2009, will be renewed and that the Minister for Culture and Communication is favourable, in principle, to opening the International Scientific Committee to representatives of the Advisory bodies and UNESCO. An executive committee will also be set up to ensure administrative and technical follow-up and this will dissociate the scientific advice from the overall administration. The administrative authority will be the responsibility of the regional director of cultural affairs but entrusted to the conservator of the cave of Lascaux, while the scientific authority will be entrusted to the scientific director of archaeological research.

b) Sanctuarisation of the hill

On the issue of isolation or “sanctuarisation” of the hill, the State Party has confirmed that, on the basis of a research project by the University of Bordeaux, which showed that the water catchment area for the cave was larger than the area in State ownership, the State Party embarked on a series of land acquisitions in order to acquire the whole watershed which should be completed by 2010. Since 2006, the “sanctuarisation” of the hill has been part of the local plan of the commune of Montignac. This will ultimately lead to a ”re-naturalisation” of the hill, linked to moving parking spaces and the creation of a centre of interpretation. A work group has been set up to take forward this process.

c) Conservation works

The report outlines the effects of the recent works carried out in the cave. In November 2007, the Scientific Committee recommended further biocide treatment on certain zones and then to leave the cave at rest for three months. The intervention was carried out by specialized restorers in January 2008. Follow-up has showed that there was an unquestionable reduction in metabolic activity on nine of the eleven pilot zones.

In certain sections, in particular on the walls of the Apse, in spite of regular cleaning, the micro-organisms are still present. New appearances on the vault of the Passage and the vault of the Apse have been observed, but with a rate/rhythm of development slower than the phenomenon of the “black spots” between December 2007 and June 2008. However, the comparison between recent photographs and those taken in June 2008 makes it possible to observe a deceleration of the development of visible fungus colonisations. A photographic analysis will be carried out in February 2009 in order to establish a precise cartography of these evolutions.

In July 2008 it was decided to test a combination of manual cleaning and biocide treatment on various types of moulds (“black spots”) observed in the right part of the cave to evaluate the effectiveness of this coupling and to consider other areas where it might be used (for instance where there is a brittle calcareous substrate).

In July 2008, members of the International Scientific Committee drew up a protocol of intervention and follow-up, based on the idea of testing possible intervention, investigating their subsequent effectiveness and using computer simulations of the interior climate in various parts of the cave. Four test areas were then identified each of which has different geological, archaeological and microbiological conditions. The zones treated within the framework of this impact study will be the subject of a regular evaluation and a microbiological follow-up, during the year 2009, in order to ascertain the effects of different cleaning and biocides treatments.

In parallel with the impact study, two research programmes will be set up in 2009. The first, entrusted to a German microbiologist, relates to the study and the evaluation of pesticides biocides which might be applied if the situation required it. The second relates to the microbial ecology of the cave of Lascaux and the metabolic activity of the mushrooms with production of melanin which compose the majority of the “black spots”. A cave without archaeological interest, but selected on the basis of its similarity with the cave of Lascaux, will be equipped as an experimental site.

d) Climatic Control

A working group has been set up in order to develop a collective reflexion on the hygrothermic control of the cave. Although broad parts of this work programme have been completed, the very precise exploration of the biological landscape of the cave remains to be researched. Two further years work will be necessary.

As in parallel with the research, mushrooms and bacteria have continued to multiply and diversify; the report underlines the fact that only when all the microbiological complexity and its microclimatic context have been understood, will it be possible to define the actions needed to stabilize the biological balance without resorting to chemical treatments.

e) Communication

After each International Scientific Committee meeting, information is now immediately transmitted to the press and is also available on the internet. Furthermore, several articles have been published and an International Scientific Symposium was organized by the Ministry of Culture. A file on the research agenda and on progress has been deposited for interested State Parties with the Ambassador to UNESCO.

f) Future work

From the beginning of 2009, the Scientific Committee will focus its efforts on three areas: 1. Completion of microbiological studies; 2. Development of a new system of climatic control and 3. Control of the external environment of the cave.

g) International Symposium

From 26 to 27 February 2009, the State Party hosted an International Scientific Symposium regarding the state of conservation of the property entitled “Lascaux et la Conservation en Milieu Souterrain”. Experts from 12 countries were invited to attend the symposium along with representatives of ICCROM, ICOMOS and UNESCO. At this symposium, both scientific and management aspects of the conservation of the property were discussed. The Minister of Culture, who opened the meeting, reiterated the commitment of France to support all research and conservation activities needed for the safeguarding of the cave. She further indicated that the State Party was open to working with recognized experts from around the world with knowledge of conservation of prehistoric painted caves. The conclusions of the international symposium emphasized the importance of pursuing an international, multidisciplinary debate regarding the Lascaux caves, the need for conducting thorough impact assessments before all interventions, and the establishment of “report card” on the health of the caves every six months. In addition, the following decisions were announced: (a) The installation of a new independent, international scientific committee; (b) The putting in place of the necessary investments for the conservation and research programmes; (c) The opening of a “study cave” to test potential treatments and interventions; and (d) The protection of the hill surrounding the Lascaux caves. The proceedings of the symposium are under preparation.

h) State of conservation and results of the reactive monitoring mission

On 17 March 2009, an ICOMOS mission visited the property and inspected the cave. The mission report which is available at https://whc.unesco.org/en/sessions/33COM/ considered the overall state of conservation of the site and the work of the International Scientific Committee to be satisfactory.

The impression from the short visit was that only a small amount of the overall painting has been affected by the mushrooms or black spots. Only 14 figures of painted or engraved animals out of a total of 915 were directly touched by mushrooms/melanin; and the presence of the black spots, in spite of reduction in the contrast of the figures against the rock, affects only a little the direct observation and reading of the painted figures.

With regard to the identification of the causes of the microbiological threats, it was noted that the latest hydro-geological analyses presented to the mission indicated the presence of nutritive elements in the water leaching from the walls which confirms that human activity contributed nutritive elements for the bacteria and mushrooms. The specialist in hydrogeology suggested that the origin of these nutritive elements could be the presence of the molecules of biocides or the products of their decomposition, which must be evaluated before deciding new biocides treatments. This thesis is however refuted by the microbiologist of the Laboratoire de Recherches des Monuments Historiques (LRMH). The views on the undesirable medium- and long-term effects of biocides reflects a disparity between the microbiologists on the International Scientific Committee of the Cave of Lascaux. However the mission considered that the Committee has the mechanisms to resolve these differences.

The mission considered that there can be no doubt about the co-operation between the Ministry for Culture and Communication and the International Scientific Committee for Lascaux and that the management is of sufficient intensity and quality. The revised arrangements for the International Scientific Committee, due to be implemented in June 2009, will allow the Chair of this Committee, after discussion with specialists, to propose criteria for intervention which are in line with research findings. It will be the responsibility of the Ministry of Culture and Communication to implement these through the people responsible at the property. There will thus be a separation of technical and administrative functions.

The reactive monitoring mission considered that the Scientific Committee had benefited from the foreign specialists from Spain, Italy, and Germany. The mission also considered that it would be desirable to maintain the presence of the same specialists and current scientists on the Scientific Committee while reinforcing it with further external experts. The mission considered that the presence of observers from the Advisory Bodies (ICOMOS, ICCROM or IUCN) could be positive.

Concerning conservation interventions, the mission considered that it would be helpful for the protocol on interventions to be a public document. It could be used as a model for other painted caves.

The mission noted that regular information is available, on line, on the Internet site of the Ministry of Culture and Communication. The International symposium “Lascaux and the conservation in underground medium”, held from 26 to 27 February 2009 in Paris, to discuss the current state of conservation of Lascaux, and work in progress was a model of public communication. While acknowledging the work carried out, the mission considered that it would be helpful to establish a communication plan in order to develop a consistency in what is made public.

i) Overall comments

The mission recalls that conditions in the cave have been transformed by human action over the past 65 years, particularly through the installation of the ventilation system, all of which have contributed to recent microbiological crises. It is not possible to return the cave to its preceding state (and anyway there is no technical knowledge of this state). The aim must be to find the most beneficial equilibrium possible based on existing knowledge and current technologies. However, even with good management and conservation mechanisms, there is no guarantee that in the future environmental or microbiological accidents will not occur again.

The mission did not consider that there had been serious and irreversible deterioration of the paintings, nor could it be said that actions taken are irreversible or in opposition with conservation. There is disagreement on the application of biocides but the International Scientific Committee has mechanisms to resolve these differences adequately. The threats and the risks which affect Lascaux are being correctly addressed with the current level of microbiological knowledge in spite of the professional debate on biocides. In this regard, in the absence of a further crisis, the mission considers that it is necessary to act with prudence in the context of the prevention and evaluation of impacts in the short- and long-term. The mission did not consider that overall there were arguments to support the idea of considering Lascaux for the List of the World Heritage in Danger.

The World Heritage Centre and the Advisory Bodies consider that the State Party has made progress in setting out a rational approach to monitoring, intervention, research and communications, and in putting forward proposals to strengthen the functioning of the International Scientific Committee, as a multi-faceted group of experts, and to separate scientific and administrative authority. This has helped to allay fears about the impact of the latest outbreak in the cave and allowed an understanding of the basis for future work. Clearly the cave is a highly complex unit and only when its microbiological complexity and its microclimatic context have been fully understood (including its external climate) will it be possible to define the actions needed to stabilize the biological balance without resorting to chemical treatments. Howeve,r while research is being carried out, mushrooms and bacteria continue to multiply and diversify, so future active measures will need to be taken to slow down these processes, and in due course eliminate their impacts, but these need to be carried out with the utmost prudence.

The World Heritage Centre and the Advisory Bodies note the future work plan adopted by the International Scientific Committee and consider that it would be helpful to articulate more clearly the timeframe for the various activities. They welcome the proposed re-structuring of the management arrangements to allow a differentiation between scientific and administrative responsibilities and to strengthen representation on the scientific committee and consider that these need to be implemented as soon as possible. They also welcome arrangements put in place to share information on the overall approach to research, analysis and interventions. They consider that there is a need to define clearly the methodological approach for the conservation interventions being undertaken and proposed.

The World Heritage Centre and the Advisory Bodies note that a rigorous approach needs to be taken to address all the issues raised both during the International Scientific Symposium of February 2009 and by the reactive monitoring mission carried out in March 2009.