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The Book of Stone
opportunities for study and responsibilities of conservation
Paolo Forti, Paolo Agnelli, Stefano Vanni Caves and Science The aesthetic value of caves is well-known right around the world. However, few people know that natural caves are a significant laboratory in which it is possible to conduct studies and research that, in many cases, it would be impossible to carry out elsewhere. Caves are characterised by a total absence of light, and often by minimal variations of the main environmental parameters (temperature, relative humidity, etc.). Inside them, the flows of energy (physical, chemical and biological), dampened by the great thickness of the rock, are extremely low compared to the outside. The particularly stable cave environment constitutes, then, a perfect “accumulation trap”, in which whatever is deposited there remains there intact (Fig. 1). These properties mean that an ever-increasing number of scientists are taking an interest in the underground environment. All of the different branches of geology are encompassed by caves. However, limiting the scientific interest of natural caves to this field alone would be a schoolboy error: in contrast to what may be expected, other fields of science can also learn as much from caves as geology can, if not even more (Tab. 1). Over the past fifty years, the importance of cave deposits has increased markedly, especially in the fields of paleoenvironmental studies and paleoclimatology. Thanks to
Tab. 1
them, it is now possible to reconstruct with considerable accuracy the chronology of the climatic events that have taken place in a given geographical area over a very long time period, which can reach or even exceed tens of millions of years. From this perspective, concretions are far and away the most important cave deposits, because their banded structure is ordered chronologically (the upper bands are necessarily younger than those below). There are various laboratory techniques that enable precise absolute dating, sometimes down to a specific year or even less. Due to their laminated structure, concretions can be considered a bona fide “Book of Stone”: each growth band corresponds to a page of a multidisciplinary encyclopaedia. Caves as delicate ecosystems One particular chapter in this encyclopaedia concerns biospeleology. At least until the early 19th century, it was thought that in the total absence of light nothing could grow or develop. Only after the initial studies of insects in Postojna Cave (1831) was it realised that, in actual fact, the animal life in this environment was very particular and very different from that of the surrounding external environment. It was then that we began to understand the importance of biospeleology and of caves as the ideal laboratory for studying the mechanisms of natural selection in an environment that was more contained and populated by fewer species with respect to the external ecosystems. From then on, it was clear that in caves there is not only an abiotic component (rocks, minerals, water, speleothems, etc.) but also a biological component, which contributes to the formation of a complex and fascinating hypogeal ecosystem. As things stand, we are currently in a position to read only the titles of the chapters and the first few paragraphs of this book of stone. In the near future, when research and enhanced technology will enable us to read all of the pages, the scientific importance of caves will increase exponentially. This will necessarily result in a major increase in demand for the analysis and study of an ever-larger number of natural caves, coming in part
