ROCKinBIO

BRINGING THREE WORLDS TOGETHER

The magnitude of the undesirable changes produced by biological colonisation, i.e. biodeterioration, is strongly determined by the individual characteristics of the colonising organisms, and possibly influenced by their community structure, but cannot be fully accessed if isolated from the synergistic influence of the multi-scale environmental (climatic, geological) factors superimposed upon, and interacting with species action to produce rock biodeterioration. An integrative approach is required, collecting robust evidence from studies of the all these fields of knowledge thus providing a fuller view of how the rock surface ecosystem under study operates.

→ Biology

A specialised and diverse group of organisms, from bacteria to higher plants, are among the persistent settlers of exposed rock surfaces. These rock-colonising organisms are important agents of rock breakdown due to a wide range of geophysical and geochemical changes they produce. Such pioneering biological effects on bare rock surfaces pave the way for ecological succession, initiating soil development but may have negative consequences for open-air rock-art. Since most rock-art is superficial and deterioration can easily erase the motifs, biological colonisation is usually thought to pose a major conservation threat.

→ Geology

The susceptibility of a rock to biological colonisation, i.e. its bioreceptivity, is a reflection of the intrinsic properties of the rock. Laboratory and field-derived microscopic and spectroscopic point-based quantifications need to be upscaled to the whole surface, otherwise risking to fall into a reductive view of the deteriorating dynamics, and missing the ability to portray fine-scale patterns of variation of key geological factors useful to predict biodeterioration rates synoptically.

→ Climate

Evidence suggests that the rates of open-air rock-art deterioration may be increasing, but it is still unclear whether this is due to local factors or wider environmental influences accelerated by climate change. Two potential impacts standout: changes in the composition and structure of rock-colonising communities as organisms attempt to track changes in environmental conditions and changes in the function of those communities as the environmental factors that regulate their biological processes are being altered. These two impacts are linked, as changes in community structure and composition usually have a knock-on effect on ecosystem function. Contrasting microclimates offered by different rock surface exposures in the Côa Valley create the necessary setting for testing the resilience of rock-colonising communities and their function as rock breakdown and open-air rock-art deteriorating agents, in face of future climate change scenarios.