Current overlapping distribution of megaherbivores and top predators: An approach to the last terrestrial areas with ecological integrity

Abstract

The Earth's wildlife is facing a new, fast and huge extinction process due to the impact of humans. This scenario not only affects the biodiversity itself but also the capacity of the ecosystems to retain their structure and functions. The roles of megaherbivores and top predators are crucial for ecosystem ecological integrity and key in many eco-evolutionary processes. We provide a global overview of the current ecological integrity of terrestrial surfaces, built through an inventory of the areas that still preserve their integral community of megaherbivores and top predators. The targeted species were the taxa present during the upper Holocene, which represents the ecological scenario before the current biodiversity crisis caused by humans. We established the ecosystem's ecological integrity by mapping the areas where all targeted taxa are currently present. We used the maps provided by the Red List of the International Union for Conservation of Nature and the information obtained through a bibliography review for the former distribution ranges to build the cartography. We identified 81 areas with a full community of megaherbivores and top predators, most of which are very small in size (<10.000 km2). Only eco-regions that have the lowest species diversity have large patches of ecological integrity, mostly overlapping with large areas of Intact Forest Landscapes. Overall, 15.8 % of the Earth's terrestrial surfaces currently retain their target taxa. Our results are an important complement for the available maps of ecosystem ecological integrity, since we offer a detailed global inventory of key areas for conservation of functional wildlife.