Predators’ Effects on Ecosystem Entropy

Abstract

The are far-reaching changes to ecosystems that result from the loss of apex consumers, in particular, large reductions in vegetation brought about by unregulated herbivore populations in such systems. Beside increased atmospheric CO2, there is another important consequence of losing large terrestrial predators and their top-down effects. When photosynthetic capacity is reduced, heat dissipation through evapotranspiration is also reduced. Some models estimate that evapotranspiration’s contribution to global warming is greater than that of CO2 by one to two orders of magnitude. Trophic downgrading thus not only alters ecosystems at plant levels, but reduces the rate of entropy production, which increases surface temperature variation. These indirect effects may have substantial consequences for biodiversity and ecosystem functions.