Biotic impoverishment

A central goal of ecologists today is to be able to predict the environmental consequences of humanity’s alteration of life on Earth. We have changed our world so much that many propose considering the Holocene officially over and naming this new epoch in Earth’s history the Anthropocene (Crutzen, 2002; Zalasiewcz et al., 2008). Several features distinguish the Anthropocene from the Holocene, but changes in the diversity of life are among the most prevalent. These include: • the absence of megafauna species once common in the Pleistocene now extinct in part because of human hunting (Barnosky et al., 2004), • the increasing loss of top predators and other apex species (Estes et al., 2011), • the rise of agriculture that now covers 40% (Ramankutty et al., 2008) to 75% (Krausmann et al., 2013) of the vegetated surface of Earth, • a 10–100 fold increase in extinction rates that is propelling us towards a sixth mass extinction (Barnosky et al., 2011), • and the likely collapse of most of our fisheries in the next 50 years (Worm et al., 2006).