Shifting baselines and the forgotten giants: integrating megafauna into plant community ecology

The extensive, prehistoric loss of megafauna during the last 50 000 years led early naturalists to build the founding theories of ecology based on already‐degraded ecosystems. In this article, we outline how large herbivores affect community ecology, with a special focus on plants, through changes to selection, speciation, drift, and dispersal, thereby directly impacting ecosystem diversity and functionality. However, attempts to quantify effects of large herbivores on ecosystem processes are markedly scarce in past and contemporary studies. We expect this is due to the shifting baseline syndrome, where ecologists omit the now‐missing effects of extinct, large herbivores when designing experiments and theoretical models, despite evidence that large herbivores shaped the physical structure, biogeochemistry, and species richness of the studied systems. Here, we outline how effects of large herbivores can be incorporated into central theoretical models to integrate megaherbivore theory into community ecology. As anthropogenic impacts on climate and nutrient levels continue, further warping ecological processes and disconnecting species distributions from optimal conditions, the importance of quantifying large herbivore functionality, such as facilitation of dispersal and coexistence, increases. Our findings indicate that current scientific attention to large herbivores is disproportionate to their past impacts on habitat structure and evolutionary trajectories, as well as the role large herbivores can play in restoring diverse and resilient ecosystems.