Climate change, adaptive cycles, and the persistence of foraging economies during the late Pleistocene/ Holocene transition in the Levant
Publication Year: 2012
Journal: Proceedings of the National Academy of Sciences of the United States of America
Categories: Organizational Change
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.
As mentioned in the abstract, the article is about climate changes during the Younger Dryas (~12.9 – 11.5 ky B.P.). The theory of adaptive change (TAC), also known as resilience theory, is described. TAC states that processes in human and environmental systems are interlinked at different spatial/temporal scales of operation and modeled as adaptive cycles. The cycles move dynamically through four phases (r, K, Ω and α). The r-phase is defined as growth or exploitation, with trends to cultural conservatism and eventual high interconnectivity of the components in the K-phase. The K-phase exhibits the least flexibility and the lowest resilience and potential for change, leading to a release and reshuffling in the Ω-phase. Many researchers equate the end of a K-phase with the collapse of a civilization. The K-phase is followed by reorganization and renewal in the α-phase. The α-phase has the highest potential for innovation and adaptability, drawing both on traditional solutions maintained within social memory as well as innovations that later contribute to the array of known possible solutions within the cultural repertoire, and a new cycle begins. Although TAC is used to examine the interrelationship between climate change, cultural change, and human decision-making about selection of plant and animal resources, the article is relevant for the topics we are studying. Holling (2001) used the TAC either in his article “understanding the complexity of economic, ecological, and social systems”. That is an important article for the course. The figures of the adaptive cycle in both articles are different (see figure 1 and 2), but their meaning is the same.
Organizations have to react on changes. This can be all types of changes, e.g. climate changes, cultural changes or ‘black swans’. The adaptive cycle describes the process of this reacting mechanism. The article of Rosen & Rivera-Colleza is hard to read. They use a lot of ‘old terms’ (to describe the past eras), but it is a good example of describing the adaptive cycle. It is also evidence for the fact that the idea of an adaptive cycle is very old. The adaptive cycle could be used eras ago.