Assessing Resilience Capacities and Vulnerability in Agropastoral Societies using an adapted Lotka-Volterra modelling framework

Diversity in the responses of species to environmental variability is fundamental to building ecosystem resilience. In behavioral ecology, risk refers to variance in the outcomes of behaviors with near-term (i.e., fitness-related) consequences, and humans are especially skilled at finding innovative ways to minimize subsistence risk. Formal models for risk-sensitive decision making can reveal how particular combinations of subsistence activities minimize variance arising from climatic and environmental conditions. However, an analytical framework for assessing the extent to which the diversity of these activities promotes the capacity for human social-ecological systems (SESs) to absorb disturbances and reorganize and renew themselves is yet to be developed, and hence we are unable to reliably address resilience in ancient SESs. Here, we adapt a population dynamics model of multiple interacting and mutualistic species to simulate the impacts of external (i.e., climate) variability on equilibria. In this approach we treat three alternative, yet complementary subsistence strategies (i.e., cultivation, pastoralism, and hunting) as interacting species in a heterogeneous environment. We parameterize interaction effects between the three “species” based on payoff matrices that define the relative benefits of one strategy over another to subsistence farming economies. Different combinations of subsistence activities are expected to arise as payoff matrices are subject to variable climatic and environmental constraints on productivity. We use downscaled TRACE21K-II output variables to simulate interannual variation in returns from each strategy. The simulation produces a time series of idealized proportional contributions of each strategy to overall subsistence. We then test the model predictions against macrobotanical and faunal remains recovered from lakeside settlements (i.e., pile dwellings) in the Northern Alpine Foreland spanning to the Neolithic (6.2-4.3 kya cal. BP).