Conservation paleobiology of the Montalbano Jonico succession (southern Italy): A Standard Auxiliary Boundary Stratotype (SABS) for the Middle Pleistocene of the Quaternary System

Conservation paleobiology (CP) is a relatively new, synthetic field of research that combines paleontology theories and analytical methods to address current issues related to conserving and managing biodiversity and understanding long-term present-day ecosystem dynamics.   This research focuses on the latter aspect of CP and investigates how macrobenthic communities have responded to climate change in the past in the Pleistocene marine setting of Montalbano Jonico (Bradanic Trough, southern Italy). Specifically, being a SABS, the Montalbano Jonico Ideale Section presented a significant opportunity to explore past macrobenthic environmental dynamics of shelf marine environments in a data-rich and well-known environmental and stratigraphic framework. We quantified responses of shelf macrobenthic assemblages to long-term climate changes using 29 samples (∼ 3,975 fossil remains) retrieved along the SABS, deposited between MIS 20 and MIS 18. Previously established paleo-bathymetric reconstructions indicate shelf environments during cold periods (glacials and stadials), which alternated with deeper settings (outer shelf/slope) during warmer phases (interstadials), reflecting the orbitally-driven climate shifts registered by stable oxygen isotopes. Shelf macrobenthic assemblages naturally alternated between two states over observed long-term climate oscillations. Cold climate faunas were characterized by lower species richness and negligible abundance of species exclusive to the Mediterranean-to-Lusitanian regions compared to warm interstadial assemblages. The high similarity between cold climate assemblages and the distinct composition and abundances of interstadial faunas suggests that, over millennial timescales, shelf benthic assemblages have been primarily structured by environmental forcing, proving either remarkable resilience or persistence in the face of significant environmental and climatic perturbations. In addition, being the interglacial MIS 19 a climate analog for future climate change, paleobiologic features (e.g., standardized richness or amount of most abundant taxa) might serve as an ecological baseline for the near future. While biomonitoring, ecological data, and strategies are the main avenues for conservation and ecosystem management, conservation paleobiological approaches can provide unique insights from the recent past into biodiversity dynamics and ecosystem structure of present-day ecosystems that would have otherwise gone unnoticed.