Ecological analysis and biodeterioration processes over time at the Hieroglyphic Stairway in the Copàn (Honduras) archaeological site

The Copan Hieroglyphic Stairway, one of the most important monuments of the Mayan culture, was excavated at the end of the 1800s. After a few decades it was extensively attacked by mosses and lichens. Different biocide treatments were applied in the late 1970s, and consolidation and stabilization works were carried out in the 1980s and 90s; a tarp was installed in 1985 over the Stairway for protection from rain. The present investigation shows an almost total death of lichens and a heavy reduction of the biodeterioration phenomena on the stone surfaces of this monument. The most frequent species presently growing are cyanobacteria and a few green algae. Notwithstanding this relatively low level of superficial colonization, cross-section staining and SEM analyses at times revealed a heavy biological growth just below the surface. The main structures found were exo-polymeric substances, fungal hyphae and moss protonema. Through a comparative analysis of the bio deteriorative phenomena of other monuments at the site, and with historical records, the relationships between the main ecological factors (water and light) and the biological colonization at the Copan archaeological site are described. The ecological analysis and the changes that seem to have occurred in the biodeterioration of the Stairway provide useful information for planning future conservative interventions.