Valentí Rull is biologist with a PhD in Paleoecology. During the last 40 years, VR has used past ecological evidence to address topics such as i) the type and characteristics of biotic responses to environmental change; ii) the role of human and climatic drivers as causes of ecological change; iii) the role of tectonics, paleogeography and climate change on the origin of biodiversity; iv) hypotheses testing on long-term ecological processes; and v) predictions on biotic responses to eventual future climatic scenarios. VR has conducted his research on several temperate, tropical and subtropical regions as for example the northern tropical Andes, the Orinoco lowlands and delta, the Guayana region, the Maracaibo basin, Easter Island, the Azores Islands and the Pyrenees. Dr. Rull has published 12 books and more than 280 articles, and has been included in the Stanford World's Top 2% Scientists for the period 1996-2020.Christopher M. Stevenson received his Ph.D. in archaeology in 1984. Previous professional experience has included cultural resource management investigations (1985-2000) within the United States and a position in the Virginia Department of Historic Resources as a regional archaeologist (2000-2011). For over 25 years he has conducted archaeological fieldwork on Easter Island (Rapa Nui), Chile, investigating regional settlement patterns and ancient farming strategies. Other areas of fieldwork include excavations at prehistoric and historic archaeological sites in Virginia, Pennsylvania, and the Canary Islands. Dr. Stevenson has published multiple books on Rapa Nui prehistory and 105 journal articles. His analytical specialties include infrared spectroscopy, hydrothermal alteration of glass, and obsidian hydration dating of prehistoric artifacts.
