Reconstructing the history of human impacts on coastal biodiversity in Chile: Constraints and opportunities

1. Although Chile is at the forefront in evaluating experimentally the importance of human harvesting impacts on coastal biodiversity, there are no evaluations of such impacts on a long-term historical basis (tens to thousands of years). Different types of archival information (i.e. contemporaneous, archaeological, and palaeontological) were used to carry out a research programme based on the historical assessment of the impacts and intensity of resource extraction on coastal biodiversity along the Chilean coast. 2. In addition to recent scientific literature, different sources of contemporaneous information (e.g. museum collections, old reports and accounts) can reveal the human impacts observed in the more recent past. Furthermore, the large number of prehistoric shell middens along the entire Chilean coast offer access to ̃ 11000 years of history along the entire coast, although the faunal composition, structure, and dynamics of most of them remain largely unstudied. 3. Finally, the rich and widespread fossil record of some marine groups provides the opportunity to reconstruct the structure and dynamics of benthic communities during different phases of human influence (e.g. pre-human, prehistoric harvesting, and modern harvesting). 4. Preliminary comparisons of fossil versus modern bivalve assemblages suggest marked changes in the species composition. Human impacts seem very recent and shifts in the structure of benthic assemblages may have occurred only a few centuries/decades ago. 5. In contrast, prehistoric harvesting, although intense, was apparently not enough to cause a profound impact on coastal ecosystems. The approach herein envisaged can provide the basis to build a historical baseline to evaluate the human impacts on the coastal biodiversity in the region.