Influence of technological progress and renewability on the sustainability of ecosystem engineers populations

Overpopulation and environmental degradation due to inadequate resource-use areoutcomes of human’s ecosystem engineering that has profoundly modified the world’s landscape. Despite the age-old concern that unchecked population and economic growth may be unsustainable, the prospect of societal collapse remains contentious today. Contrasting with the usual approachto modeling human-nature interactions, which are based on the Lotka-Volterra predator-prey modelwith humans as the predators and nature as the prey, here we address this issue using a discrete-timepopulation dynamics model of ecosystem engineers. The growth of the population of engineers ismodeled by the Beverton-Holt equation with a density-dependent carrying capacity that is proportionalto the number of usable habitats. These habitats (e.g., farms) are the products of the work of theindividuals on the virgin habitats (e.g., native forests), hence the denomination engineers of ecosystemsto those agents. The human-made habitats decay into degraded habitats, which eventually regenerateinto virgin habitats. For slow regeneration resources, we find that the dynamics is dominated byrounds of prosperity and collapse, in which the population reaches vanishing small densities. However, increase of the efficiency of the engineers to explore the resources eliminates the dangerous oscillatorypatterns of feast and famine and leads to a stable equilibrium that balances population growth andresource availability. This finding supports the viewpoint of growth optimists that technologicalprogress may avoid collapse.