Simulating an Ecosystem - Investigating the Impact of Brown Bears’ Omnivorous Behavior in a Simulated Ecosystem

Sammanfattning

This bachelor thesis investigates the omnivorous impact of brown bears on ecosystemdynamics through an agent based computer simulation. A digital ecosystem set ina Swedish forest was developed using Unity. Within this ecosystem there are threespecies: brown bears which are omnivores, wolves which are carnivores and moosewhich are herbivores. The simulation uses state machines to model each respectiveanimal behavior and interactions, states and attributes were tracked during runtime. Three main scenarios were evaluated: a scenario where no bears were present,a scenario where an average amount of bears were present and then a scenario wheremany bears were present. Each scenario was run 10 times over 900 seconds withthe same amount of resources, moose and wolves. The impact of brown bears during hibernation was also checked by taking the final populations from the averagebear scenario and using them as the start values for a winter scenario. Resultsdemonstrated that in the simulation brown bears significantly influence ecosystemdynamics. Increased bear populations correlate to reduced moose and wolf populations, increased moose fleeing behavior and decreased wolf hunting success dueto bear interference. Statistical analysis revealed that 53 out of 68 tracked metrics showed significant change between the scenarios, indicating that brown bearsworked as a disruptor for both herbivore and carnivore species. These results shouldhowever not be taken as predictive due to the fact that the simulation implementssimplified behavioral models and limited environmental complexity compared to realecosystems. The results should therefore be seen as illustrative.