Between land and sea in Puerto Rico: climates, coastal landscapes and human occupations in the mid-Holocene Caribbean

Modern human-induced climate change will have a particularly adverse impact on coastal non-industrial societies. Understanding how such changes have occurred in the past can provide better tools to address social vulnerability in these contexts. The main goal of this thesis is to consider how past non-industrial societies responded to environmental change and which conditions affected their sustainability. Here I investigate Mid-Holocene climate change and its relationship to the earliest human occupations in the Caribbean Archipelago (pre-Arawak period), using the site of Angostura (Puerto Rico) as a case study. On-site geoarchaeological tests – including microartefact and bulk-sediment analyses – were selected to study site-formation processes. Off-site sediment cores were collected and studied to address sea-level and landscape change. Archaeomalacological analysis assessed subsistence behaviour and landscape ecology. An assemblage of 18 radiocarbon dates was used to provide chronological context. To consider the dynamic and complex relationship between people and the environment, I apply the Theory of Adaptive Change (TAC) as a model to articulate scale-shifting and facilitate intra-scale comparison of biotic, abiotic and cultural elements. The various analyses show that significant environmental changes occurred during the pre-Arawak, but this had no negative effect on cultural systems. Long-distance webs of interaction, diet diversification, and landscape domestication enabled flexibility to adapt and respond successfully to change. Increasingly inflexible ‘home range’ boundaries and enhanced meso-scale rigidity lowered overall resilience of the cultural system, increasing its sensitivity to long-term landscape change. This vulnerability, however, was social; not an innate effect of changes in the environment. This observation helped identify four aspects that condition social vulnerability to change: territorial boundaries, ecosystem biodiversity, dependence on spatial configuration of landscapes, and knowledge. Understanding the interconnection between systems and their multiple nested interrelations can help develop a better understanding of the complexity of change and the meaning of sustainability within socio-natural systems