Isabel C. Rivera-Collazo

Climate change, adaptive cycles, and the persistence of foraging economies during the late Pleistocene/Holocene transition in the Levant

Climatic forcing during the Younger Dryas (∼12.9–11.5 ky B.P.) event has become the theoretical basis to explain the origins of agricultural lifestyles in the Levant by suggesting a failure of foraging societies to adjust. This explanation however, does not fit the scarcity of data for predomestication cultivation in the Natufian Period. The resilience of Younger Dryas foragers is better illustrated by a concept of adaptive cycles within a theory of adaptive change (resilience theory). Such cycles consist of four phases: release/collapse (Ω); reorganization (α), when the system restructures itself after a catastrophic stimulus through innovation and social memory—a period of greater resilience and less vulnerability; exploitation (r); and conservation (K), representing an increasingly rigid system that loses flexibility to change. The Kebarans and Late Natufians had similar responses to cold and dry conditions vs. Early Natufians and the Pre-Pottery Neolithic A responses to warm and wet climates. Kebarans and Late Natufians (α-phase) shifted to a broader-based diet and increased their mobility. Early Natufian and Pre-Pottery Neolithic A populations (r- and K-phases) had a growing investment in more narrowly focused, high-yield plant resources, but they maintained the broad range of hunted animals because of increased sedentism. These human adaptive cycles interlocked with plant and animal cycles. Forest and grassland vegetation responded to late Pleistocene and early Holocene climatic fluctuations, but prey animal cycles reflected the impact of human hunting pressure. The combination of these three adaptive cycles results in a model of human adaptation, showing potential for great sustainability of Levantine foraging systems even under adverse climatic conditions.

Human adaptation strategies to abrupt climate change in Puerto Rico ca. 3.5 ka

The connection between climatic change and social response is complex because change articulates a number of inter-related factors. Human decisions are filtered by social buffers – including social memory, risk perception, and cultural priorities – and the rate and scale of climate change is usually much larger than the scale of human decision-making. In this article, we provide information on climate change based on precisely dated speleothems with the response evident in archaeological sites that have radiocarbon date ranges within the same time frame. A stalagmite recovered from within the catchment area for aquifer recharge of the Pre-Arawak site of Angostura in Barceloneta, Puerto Rico, shows that a significant wet period occurred between 3.9 and 3.1 ka (primarily centered at 3.5 ka). We investigate the effect that this increase in precipitation had on the earliest occupations on the island in the context of palaeoenvironmental, geoarchaeological, and archaeological records from Angostura, Maruca, and Paso del Indio. Our analysis suggests the presence of two different adaptation strategies: settlement relocation and microlandscape modification. Our study concludes that the social response to change cannot be seen as monolithic given that human behavior, even within the same period, addresses the needs of individual groups with different priorities. This multiplicity of responses can indeed enhance resilience as social support can continue through alliances and exchanges, strengthening social bonds that can help buffer catastrophes. The results can help shed light on the range of adaptation strategies to change encompassed within the manifestations of social resilience or vulnerability.

Por el camino verde: Long-term tropical socioecosystem dynamics and the Anthropocene as seen from Puerto Rico

Islands are traditionally considered sensitive to environment and climate change. The Caribbean Islands are a biodiversity hotspot, where conservation efforts should be a priority. However, the archaeological record suggests that the biotic characteristics of the islands, even within nature or forests reserves, are strongly shaped by thousands of years of intense human activity. This presents an issue for conservation efforts because defining what should be preserved and what should be reconstructed is not straightforward. Using Puerto Rico as case study, this article explores how socioecosystem dynamics influenced the biotic characteristics of the island at specific archaeological periods and to what extent these processes have affected the environmental resources on the island today. Climatic data, its implications on forest type and cover, and landscape characteristics as seen from sedimentary records, combined with archaeological data on human–environment interactions over time, from the mid-Holocene to the present are used to investigate these themes. This article brings forth more questions than answers, but it reflects the status of deep-time environmental research on the island, which is still in its early stages. I argue that, starting from the earliest occupations, human influence has altered the ecology of Puerto Rico so deeply that the natural resources we work toward preserving, conserving, or restoring today cannot be understood without considering the social contexts that shaped them. In this sense, if the Anthropocene is a proposal to rename the current geological period because of the overwhelming physical evidence of change that human activity has left behind, then the history of the Puerto Rico supports the proposal for the application of the term since at least 5 ka. Applying the concept would bring the relevance of human activity to the forefront, contributing to the reconsideration of the role of humans in the formation and preservation of modern ecological systems.

The Environmental Legacies of Colonialism in the Northern Neotropics: Introduction to the Special Issue

The arrival and settlement of Europeans throughout the Americas led to unprecedented demographic and environmental transformations (Crosby 2003). The voluntary and forced migration of peoples from ...

A Deep-Time Socioecosystem Framework to Understand Social Vulnerability on a Tropical Island

ABSTRACT Archaeological research has the potential to contribute to our understanding of social vulnerability to environmental change by providing examples of change in the deep and recent past. Here we argue that human activity and historical processes deeply transform tropical environments through time, and that these changes accumulate on the landscape affecting social vulnerability. These changes, however, are not always evident due to rapid vegetation growth obscuring past human impact. Our research investigates the northernmost 25 km of the Manatí Hydrological Basin in Puerto Rico, focusing on evidence of human activity and environmental characteristics including topography, sediments and vegetation cover. The data collected, which articulates archaeological and ethnographic records, covers the span of pre-Columbian occupation of the region, through the colonial periods, and into the twentieth century. Results show that human activity through time has deeply altered the forests. The accumulation of long-term histories of biotic, abiotic and cultural dynamics affects social sensitivity and exposure. Human ingenuity can widen resilience thresholds, making long-term practices particularly important components of adaptive strategies. Deep-time socioecological perspectives can contribute to current vulnerability assessments by enhancing local and historical records that can feed predictive models and inform decision-making in the present.