Mapping nature’s power lines

Animals play a critical role in shaping ecosystem function. Despite knowing this, scientists have struggled to precisely quantify how biodiversity changes impact ecosystem function at continental scales. A new approach using bioenergetics, a measurement of energy, offers a breakthrough. In a new study from sub-Saharan Africa, scientists used the food consumption and bioenergetics of birds and mammals to discover that the region’s food webs are now operating on less than two-thirds of the energy they once used. Across biomes, declines in ecosystem function translate into lost energy. For example, the loss of bird and primate diversity has decreased the energy in forested regions. The authors found that the roles of megafauna have collapsed outside protected areas. Unlike traditional biodiversity measures, an energetics approach also highlights the importance of smaller species and other keystone animals in maintaining ecosystem function. Using bioenergetics, managers can now quantify the amount of energy species consume and pass on, revealing which species are most crucial to protect or restore to maintain ecosystem functionality.