No abstract

Coasts are dynamic environments prone to the physical and social impacts of climate change. Examining the archaeological and environmental records of coastal areas can deepen our understanding of how humans respond to changing environmental conditions. In this article we consider how sea-level rise impacted coastal environments through time, and how these changes could pose opportunities or challenges to local indigenous populations. We present new findings of coastal zone transformations and past settlement patterns for Borikén, the largest island of the Puerto Rican archipelago, during the Holocene. We use paleogeographic modeling to reconstruct ecosystem availability for six discernible coastlines at 1000-year resolutions that accounts for past relative sea-level (RSL) heights and paleotidal ranges. We then compared ecosystem availability trends with the spatiotemporal distributions of available archaeological data to demonstrate the localized impacts of climate-related RSL rise across the island’s coastal ecosystems and suggest a consideration of habitat availability in past decision-making strategies. We observe a strong presence of Archaic Period sites in the island’s southwest coast where high coastal ecosystem availability and stability were present during this period. We also observe a significant expansion of intertidal ecosystems beginning at 3 kya for the north-central, north-eastern, south-central, and south-eastern coastlines that correspond to the appearance of materials associated with Early and Late Ceramic Periods cultures in these areas. This comparison of differential coastal transformations and site distributions conveys a deeper understanding of factors involved in past decision-making strategies and contributes to the emerging picture of human adaptations amidst changing environmental conditions.

The virtual removal of forest canopies through light detection and ranging (lidar) has enhanced archaeological interpretations of settlement patterns in tropical zones. Although lidar collections of Indigenous landscapes in the Caribbean Archipelago are limited, resolutions from open-access lidar datasets reveal coarse regional settlement patterns and large-scale architecture planning. In this article we inspect the Caguana Ceremonial complex in Utuado, Borikén (Puerto Rico), using a 2016 lidar dataset available through the National Oceanic and Atmospheric Administration portal. Visual comparisons between known Indigenous sites, surface anomalies, and site inspections in the three sectors under study identified plazas, possible ancient paths into the Caguana complex, a possible agricultural area west of the site, and the ANG-4 site. This study, the first application of lidar inspections in Puerto Rican archaeology, demonstrates that open-access data can help guide research and save time in field surveys, thus improving our ability to protect the Indigenous cultural heritage hidden under forest canopies.