Prehistoric Sites and Decorated Caves of the Vézère Valley

Outbreaks of mould and bacterial spores on the surface of the cave paintings of Lascaux 

On 1February 2010, the State Party submitted a state of conservation report in response to the recommendations of the World Heritage Committee at its 34th session (Brasilia, 2010). This extensive report includes an Action Plan and detailed annexes with graphics and visualisations.

a) Overall conservation issues

No biocide treatments have been made since 2008. Conservators have continued to monitor the surfaces of the cave throughout the year in order to record the level of contamination of the painted surfaces and to assess any changes or modifications. In some non-painted zones in the lower part of the walls, manual removal of micro-organisms has been carried out under archaeological supervision.

Throughout 2010, the overall level of contamination of the cave is reported as remaining relatively stable and there have been no significant changes in the location of contaminated areas.

Regression of areas of white mould has been noted in several places. Only the vault of the passage remains a sensitive area. However between April and November 2010 there were more disappearances than new appearances of mould sites in this area.

The black spots that appeared in March 2006 are photographed twice a year, with an analysis of their numbers and disposition in the significant areas of the Apse and Nave. Their development has been slowed down and a few new spots were reported in 2010. However the apparition of new spots has been reported on the vault of the Nave. Today less than 1% of the paintings are still affected by this phenomenon.

In October 2009, the limited presence of vermiculations had been reported in the Hall of the Bulls. To understand better the evolution of this phenomenon, visual surveillance is made every week and photographic surveillance is undertaken regularly. The resulting analysis showed the slow evolution of this phenomenon with only very few new outbreaks. As there is very little scientific data on this phenomenon, a scientific study is being undertaken by the University of Bordeaux on the vermiculate phenomenon. It appears only to be active for a few weeks each year during late summer.

The multi-disciplinary research project set up in 2007 to examine the overall relationship between physical and climatic parameters and the development of micro-organisms was planned originally for three years. It concentrated on three areas of the cave. The observations tend to confirm the hypothesis that control of microclimatic conditions on the surface of the walls is essential to control microbial growth at the air-mineral substrate. The changes that affected the microclimate in the chosen areas were luckily too low to modify the surface colonization that has remained broadly stable. In the absence of visible growth of microorganisms on the surface of the walls, the appropriate collection of microbiological data proved impossible. The project was therefore re-oriented towards two new areas: one towards clay without visible fungal contamination, the other towards the sandy sediment covered with large clay, the seat of "black spots". This project will be assessed by the Scientific Council in March 2011.

A second project, initiated in 2010, is led jointly by the National Institute of Agronomic Research, Dijon and the Instituto de Recursos Naturales y Agrobiologia of Seville. This examines the microbial ecology of micro-organisms in the cave, in order to understand their metabolic needs, which may help to explain the appearance of the black spots. The objective of this project is to explore all microbial communities in the cave in order to understand the reason for upsetting their balance. The preliminary results of this project identified a new species of Scolecobasidium fungus, called Ochroconis Lascauxensis that highlights the role of the faeces of Collemboles (minute arthropods) in the dissemination of Scolecobasidium spores. This project, which will last until mid 2011, will report its findings to the Scientific Council for follow-up actions.

During 2010 a third project carried out by a partnership between l'Ecole des Mines d'Alès, le Centre National de Préhistoire, and la Conservation régionale des monuments historiques helped to develop a methodology to detect and assess any minute changes in the wall surfaces through chromatic monitoring, as means for preventive conservation.

The Lascaux Simulator has been in development since 2005. The modellers now have access to a much larger processor, ranked first in Europe and sixth in the world, which means that analysis of the data can be undertaken in a much shorter time. The Simulator is now estimating the impact of the closure of the old sliding vents and the conditions that any new climate support machine would have to address in terms of cold spots, etc. This data is being used to develop possibly a new climate support system.

The installation of an overlay roof for the machine room is scheduled for early 2011 in order to reduce the thermal impact of the water flow. This will be made of removable panels that can be dissembled quickly to ensure quick access, in the case of microbiological growth.

Currently, a “cave laboratory” is being established in Dordogne – a cave devoid of archaeological interest that has many similarities with Lascaux. Once equipped, the cave will serve as an experimental site for studying interaction processes between water, air and micro-organisms to understand the impact of each of these parameters which could be used for the management of Lascaux cave.

b) Isolation of the hill

In order to reduce the number of tourists visiting the hill area as part of the tour of the facsimile cave, Lascaux II, a feasibility study is being undertaken to relocate the car park outside the area of the karst caves. The work should be carried out between 2011 and 2012. The policy of acquiring hill land, initiated in 2007, has led to the purchase of three parcels of land. The working group established in March 2009 with the purpose of considering a new system of cultural tourism management, within the perspective of overall development of the Valley, submitted its report in June 2010 and set out several options, including a proposal for a completely new facsimile cave.

c) Communication Strategy

All meetings of the Scientific Council are now followed by Press conferences and Press Releases. The website on Lascaux hosted by the Ministry of Culture and Communication now contains details of the conservation projects, including the conclusions of the Scientific Council sessions which contain information on the intervention protocols. Publication of the proceedings of the international symposium of Lascaux, held in 2009, is expected in early 2011 and there are further publications in academic journals. In 2011, the Scientific Council wishes to establish a website independent of the current site of the Ministry of Culture and Communication for communication and information towards public.

d) Action Plan and priorities

The Scientific Councilhas identified two main objectives (priorities):

· To respond in the shortest possible time to problems indentified in the cave (e.g. black spots and vermiculations)

· To study the parameters for future interventions (e.g. possible replacement of climate support system).

The knowledge management, in case of a new potential crisis (e.g. impact of climate change), has been set up as a low priority.

To reply to these priorities four working groups have been set up:

· Microbiology, microfauna and vermiculations

· Hydro-climatology and simulations

· Surface eco-systems and relationship with underground eco-systems

· The state of the cave and its possible evolution

Each working group has defined objectives, deliverables and timelines that have been set out in detail in the report and were approved by the Scientific Council in December 2010 and January 2011.

e) Management

As reported in the last report, simultaneously with the setting up of the Scientific Council, an Executive Committee was established to take in charge technical and administrative matters. Thus, the Scientific Council will develop the conservation plan for the cave and the administration will implement the necessary actions. From 2011, the Scientific Council will meet five times a year. If necessary, further scientific experts will be invited to the meetings. In 2010, the State Party reports that 600,000 Euros have been invested in research, conservation and administration.

f) Protocol on Intervention

This protocol was issued in July 2010 by the Ministry of Culture and Communication.

g) Lascaux International Scientific Task force (LIST)

In January 2011, a spokesperson of the LIST wrote to the World Heritage Centre to express concerns at the composition of the Scientific Council. He pointed out that although there were many scientists on the Committee, there were no scientists specialising in subjects related to specific threats – such as mycologists or experts in underground climatic conditions and that the promised transparency was not in place. He reported that the information emanating from the Council was very general and considered that there was a need to renew the machinery installed in 1999-2000 and to repair the sliding vents.

On 15 March 2011, the State Party replied to these points. It considered that many of the points had been addressed in their State Party report – such as the list of members of the Scientific Council that showed the participation of mycologists. The LIST representative was invited to the next meeting of the Scientific Council.

h) International Committee for the Preservation of Lascaux Foundation (ICPL)

In January 2011, the ICPL sent a report to the World Heritage Centre suggesting that the Cave of Lascaux might be considered as a pilot project, as mentioned in Decision 34 COM 5D of the Committee which suggested that pilot projects might address “the relation between conservation and sustainable development at regional/ecosystem scales”. The report acknowledges that the interventions at the cave in the 1940s destroyed the cave’s natural climatic system that had protected the paintings. ICPL considers that the engineers of the 1960s understood the need to intervene to mimic the natural systems through providing a barrier to insulate the cave from changes in outside temperatures and introducing a regulated air flow, and that the forced air system installed in 2000 (although recently adjusted to assist the cave’s breathing mechanism based on the natural convection currents) reflected the opposite of sustainability and that recent interventions have aimed to modify the cave’s ecosystem. The ICPL thus asks the Scientific Council to re-examine priorities with the goal of restoring what they describe as “a sustainable ecosystem that can survive and thrive without humans having to continually add or take out of the system”.

Replying to a request of the Centre on the above issues, the State Party considers, in its letter of 15 March 2011, that it is not correct to say that the new system installed in 1999 ‘forced air’ into the cave as the system has satisfactorily controlled the climatic conditions. It also points out that at the time the cave was discovered, the paintings were not in perfect condition and had already suffered some loss. It considers that it is problematic to define an ‘ideal’ or natural state for the cave as we do not know enough about the climatic condition that prevailed over thousands of years, and furthermore the outside condition of the hill have changed drastically even in recent centuries. The State Party further considers that the proposal of the ICPL seems to be based simply on the notion that it is sufficient to control the flow of air, and that the complexity of the cave systems, combined with the diversity of conditions it experienced over 18,000 years mean that a simple climatic model is not possible and that equilibrium will also need to include biological considerations if the cave is to be transmitted to future generations.

The World Heritage Centre and the Advisory Bodies note that the cave is now reported to be comparatively stable in terms of levels of contamination. There appears to be regression of areas of white mould, black spots and reticulations over most of the affected areas, with only a few areas now deemed to be ‘unstable’. They further note that the Scientific Council has strengthened its operations through the development of four sub-groups and that these have set out priorities and detailed action plans for the next 3 years.

The research so far undertaken has identified a new microbial species of Scolecobasidium, called Ochroconis Lascauxensis, and that its dissemination seems to have a symbiotic relationship with a minute arthropods, Collembole. The lack of information on these organisms is highlighting the specificities of the Lascaux problems and the need for more research. In view of the restricted access at Lascaux, the importance of surrogate caves for research and experimentation is growing, and the Council is responding to this need.

The overall report contains a wealth of information on the on-going investigations. From the comments of ICPL and LIST it is clear that knowledge of the full extent of what is being undertaken, the range of specialists involved, the rationale for the actions and the time that will be needed to fully model the cave and understand the enormous complexities of its eco-systems are not fully appreciated by those outside the structure. The World Heritage Centre and the Advisory Bodies welcome the aim of the Scientific Council to establish a separate web-site for Lascaux, but urge the State Party to develop a communication strategy for disseminating information about the web-site, as requested previously by the Committee.