Supplementary material from "Freshwater mollusc sclerochronology: trends, challenges, and future directions" (Stringer and Prendergast 2023, Earth-Science Reviews)

Freshwater is an essential resource for human life; however, its future availability is of ongoing concern due to the impacts of climate change, industry, and population pressures. Freshwater mollusc sclerochronology regularly contributes to questions of direct relevance to the future sustainability of this resource, as well as the conservation of endangered freshwater mollusc species, and its relationship with humans through time. Despite this, research within mollusc sclerochronology overwhelmingly focuses on the analysis of marine species. To encourage more interest in this vital subdiscipline, this paper reviews publications on freshwater mollusc sclerochronology published between 2000 and 2021 and highlights key themes and essential findings, challenges, and opportunities specific to freshwater mollusc sclerochronology. The present study reviewed 111 publications where researchers studied the incremental growth structures and/or completed temporally constrained geochemical analysis of the growth structures of freshwater molluscs, as well as 22 review papers that addressed freshwater mollusc sclerochronology research. The review identified a focus on the analysis of bivalve taxa from river or lake habitats in the Northern Hemisphere and found that research generally could be divided into four key areas of interest: development of methodology, conservation of habitat or species, paleo-reconstruction, and archaeology. The paper also considers the effectiveness of different methodologies and geochemical proxies within freshwater contexts and aims to identify unique challenges faced by researchers in the hope to aid and direct future investigations. One key challenge facing this field is the variability of freshwater environments and the need for more high-resolution monitoring of habitats in modern calibration studies. Opportunities for future research include the development of low-cost methodologies to aid in the accessibility of this technique to researchers across the world.