Marine prey vulnerability versus resilience to human foragers: insights from agent based modelling

Abstract

The resilience and susceptibility of key marine organisms to human predation and environmental change is a topic of importance to archaeologists, wildlife managers, and conservation biologists. While contemporary studies are useful for linking managerial strategies to prey population patterns, zooarchaeological assemblages when combined with computer-based simulation methods provide additional insights into marine prey resilience or susceptibility to harvesting pressures over the long-term. In this paper we generate a set of predictions, drawing on concepts from life-history theory, and then build an agent-based model to examine how energetic return rate and age at reproductive maturity influence prey resilience to foraging pressures. Our agent-based model results are then compared with archaeological observations from a limited number of Pacific island assemblages to assess the validity of the model. The results of the simulation indicate that prey taxa with low energetic return rates which reach reproductive maturity at young ages are more impervious to human predation than those which reach reproductive maturity later in life and have greater energetic returns. The archaeological assemblages examined support these key findings and suggest that the susceptibility of marine organisms to human predation is likely to be multi-faceted and context dependent. Our results also demonstrate the utility of agent-based modeling as a technique for establishing the dynamic sufficiency of competing explanations and for generating new hypotheses.