Megafauna research
An artists' creation of the Pleistocene Era at White Sands, N.M.
Credit: Karen Carr

UNM Professor Dr. Felisa Smith is co-organizer of a special issue released online today in the prestigious journal Proceedings of the National Academy of Science USA. The issue is designed to understand the decline of megafauna and consequences of large-bodied mammals around the world.

The effort includes several research papers in an effort that stemmed from a conference titled Megafauna and ecosystem function: from the Pleistocene to the Anthropocene, Smith co-organized at Oxford University, which also resulted in a special feature in the journal Ecography.

“Understanding the role of megamammals in contemporary ecosystems and the consequences of their continued decline is essential for effective management of the remaining wild areas on Earth” said Smith. “Everywhere, large mammals are in trouble because of a disastrous combination of hunting, poaching, habitat alterations, and loss of habitat.”

The conference at Oxford brought together paleontologists, conservation and environmental scientists to characterize the influence of large animals on ecosystems. Integrating historical perspectives of Late Pleistocene ecosystems when large-bodied animals were still widespread, with modern studies of areas with varying levels of intact megafauna, the aim was to develop a more holistic understanding of the consequences of the ongoing decline of large-bodied animals around the Earth.

“The loss of apex consumers is called ‘trophic downgrading’ and is a huge concern,” explained Smith. “The megafauna extinction 13,000 years ago is a good proxy for understanding how the loss of hundreds of millions of large bodied animals influences ecosystems.”

The terminal Pleistocene megafauna extinction led to the loss of all mammals in the Americas over 600 kg in a relatively brief span of time. For decades, scientists have argued about whether climate or human hunting was the culprit. Estimates suggest that perhaps as many as half a billion ‘megamammals’ were extirpated from North and South America. But the researchers suggest that the consequences, not the cause may be more important to understand.

“Studying the effects of this earlier Pleistocene trophic downgrading can shed important light on the role of large bodied animals today,” said Smith. “Integrating those efforts with modern studies is really the only way to understand how the loss of charismatic megafauna like elephants, rhinos and giraffes will impact vegetation and other animals.”

The conference that led to this work was convened at St. John’s College at University of Oxford and co-organized by Yadvinder Malhi, Chris Doughty as well as Smith. It was the first to pull together experts from a variety of fields including conservation biology, molecular biology, biogeochemistry/ nutrient recycling, rewilding, and paleontology to examine the ecological interactions of large-bodied animals and their influence on the Earth over various temporal, spatial and hierarchical scales.