Tick tock, the countdown has started: the loss of the coastal archaeological heritage of the French West Indies, between emergency and strategy
Tic-tac, le compte à rebours a démarré : la perte du patrimoine archéologique côtier des Petites Antilles françaises, entre urgence et stratégie
Résumé
Coastline regression linked to coastal erosion is an active phenomenon of great magnitude in the French West Indies where recent studies based on the analysis of historical aerial photographs indicate a shrinkage of the beaches that can reach 0.5 to 2 m per year. The impact is even more pronounced because of the insular context where the coastline is over-represented: 250 m of coastline per km² of territory in Guadeloupe as against 11 m per km² in mainland France. Moreover, archaeological sites are particularly affected in the West Indies as past occupations are distributed for the most part in the coastal fringe. This is shown by the 5000 years of Amerindian chronology, during which open-air camps, villages and specialized sites have always been associated with the exploitation of marine resources: thus 47% of the pre-Columbian occupations are located less than 100 m from the coastline. During the colonial period, the coastline remained a privileged location for the settlement of populations even if the connection with the coastline seems less marked (18% of the sites are less than 100 m from the coastline), mainly because of the development of intensive farming. Commercial exchanges and confrontation between colonial countries led to the development of cities, ports, industrial and military facilities. In addition, these spaces received many slave cemeteries which today have a memorial value that strongly resonates with the feelings of the populations. A recent evaluation conducted in Guadeloupe shows that about 160 sites out of the 779 identified on the coasts, i.e. 20%, are affected, to varying degrees, by risks of erosion. At least 14 of them are in a critical situation with a strong risk of destruction in the short term. This paper highlights the multifactorial nature of coastal erosion, which depends not only on the nature of the exposed substrate, with the sandy soils that are common in the West Indies being the most sensitive, but also on the diversity of phenomena at work. The effects of some of them are increasing in the context of global climate change: global sea-level rise, currently estimated by the IPCC to be at least 3 mm per year; hurricane frequency; weakening of the protection of coral reefs due to the bleaching of corals as a result of the warming of marine waters. The development of land and coast, aggravated by tourism, also contributes to the destabilization of coastal sedimentary deposits. This is accentuated by a weakening of the stabilizing role of vegetation due to the artificialization of soil; by disturbances associated with harbours and river workings, sometimes even by the structures created to fight against erosion; and by an excessive use of beaches leading to the disappearance of protective coastal vegetation. Some erosional factors that were previously predominant have fortunately recently disappeared, such as the extraction of sand for construction purposes, the extraction of coral for the manufacture of lime, and the deforestation of mangroves for the manufacture of charcoal. The threat of losing this heritage makes this not an easy challenge. Two main solutions have already been implemented by the French State services in charge of the management of archaeology: on the one hand, the physical protection of sites by measures which limit or slow down erosion; and on the other hand, the systematic study of the sites before their destruction by erosion, notably through archaeological excavations. The need to preserve the archaeological heritage of the West Indies coastlines has led us to carry out several kinds of actions, which should all be expanded: • Monitoring and evaluation of coastal erosion and its impact on archaeological sites, in order to anticipate threats and prioritize specific interventions. This approach is based on three types of actions: systematic surveys, collection of testimonies, in particular the ALOA project requesting public participation, and monitoring techniques using satellite imagery or other advanced methods; • Surveys and test pits allowing the scientific and cultural relevance of the threatened sites to be identified; • Archaeological excavation, that means safeguarding by recording, of the most exposed sites; • As a last resort: physical protection of the sites by in situ consolidation engineering. The preservation of coastal archaeological sites is actually difficult to manage because of regulatory and financial procedures that are sometimes not well adapted. Indeed, French laws, in applying the heritage code, provide for the financing of preventive archaeology by the developers (according to a “you break, you pay” principle), but do not offer similar arrangements in cases where the sites are destroyed by natural agents (no specific developer). In this case, the introduction of the financial solutions needed to implement emergency interventions is currently a case-by-case process, under the responsibility of the French State and the local authorities. A more regular means of financing —i.e. through a tax-supported fund— will probably be necessary if we are to be able to respond to this challenge of preserving the coastal archaeological heritage.
La remontée en cours du niveau marin, l’augmentation de la fréquence d’évènements cycloniques majeurs, la destruction des barrières coralliennes, l’aménagement du littoral corrélé à l’augmentation du tourisme, sont autant de facteurs qui aggravent l’érosion littorale et menacent dramatiquement le patrimoine archéologique côtier des Petites Antilles, notamment dans les territoires français d’Amérique qui nous intéressent ici. L’impact est d’autant plus conséquent dans ce contexte insulaire que l’occupation du territoire y est répartie de façon majoritaire sur la frange littorale comme en témoignent les 5 000 ans de la chronologie amérindienne, où campements de plein air, villages et sites spécialisés ont été de tout temps associés à l’exploitation des ressources marines. Les quelques siècles du développement tardif de la période coloniale ont quant à eux généré sur le littoral des installations portuaires, industrielles, militaires et de l’habitat, mais aussi de nombreux cimetières à forte valeur mémorielle. Face à cette menace deux principales solutions ont d’ores et déjà été mises en oeuvre par les services de l’État en charge de la gestion de l’archéologie : d’une part la protection physique des sites par des aménagements limitant ou ralentissant l’érosion, et d’autre part leur étude, notamment par la fouille archéologique. Il s’avère en outre qu’une réflexion sur une stratégie globale de sauvegarde devient incontournable car les interventions d’urgence sont bien souvent difficiles à mettre en oeuvre dans des délais et des coûts optimaux.
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