The overkill model and its impact on environmental research

Abstract

Research on human‐environment interactions that informs ecological practices and guides conservation and restoration has become increasingly interdisciplinary over the last few decades. Fueled in part by the debate over defining a start date for the Anthropocene, historical disciplines like archeology, paleontology, geology, and history are playing an important role in understanding long‐term anthropogenic impacts on the planet. Pleistocene overkill, the notion that humans overhunted megafauna near the end of the Pleistocene in the Americas, Australia, and beyond, is used as prime example of the impact that humans can have on the planet. However, the importance of the overkill model for explaining human–environment interactions and anthropogenic impacts appears to differ across disciplines. There is still considerable debate, particularly within archeology, about the extent to which people may have been the cause of these extinctions. To evaluate how different disciplines interpret and use the overkill model, we conducted a citation analysis of selected works of the main proponent of the overkill model, Paul Martin. We examined the ideas and arguments for which Martin's overkill publications were cited and how they differed between archeologists and ecologists. Archeologists cite overkill as one in a combination of causal mechanisms for the extinctions. In contrast, ecologists are more likely to accept that humans caused the extinctions. Aspects of the overkill argument are also treated as established ecological processes. For some ecologists, overkill provides an analog for modern‐day human impacts and supports the argument that humans have “always” been somewhat selfish overconsumers. The Pleistocene rewilding and de‐extinction movements are built upon these perspectives. The use of overkill in ecological publications suggests that despite increasing interdisciplinarity, communication with disciplines outside of ecology is not always reciprocal or even.

Demographic history and genetic diversity of wild African harlequin quail (Coturnix delegorguei delegorguei) populations of Kenya

“…It is hypothesized that during this period, human hunters were responsible for the massive extinction events and habitat destruction as they spread from Africa to other continents (Faith, 2014 ; Martin, 1967 ). However, the role played by humans in the late Pleistocene extinction events is still debated (Nagaoka et al, 2018 ).…”

Conservation biology and conservation paleobiology meet the Anthropocene together: history matters

“…The first application of stable isotopes (δ 18 O) for obtaining paleotemperature and climatic records was tested with marine mollusks (Urey et al, 1951;Epstein and Lowenstam, 1953;Valentine and Meade, 1960;Krantz et al, 1987) and as the ability to sample smaller organisms improved, deep-sea foraminifera have given us the best record of Cenozoic climate change (Zachos et al, 2001). Vertebrate paleontology, as well, presented the overkill hypothesis which focused on humans as major hunters of megamammals, leading to their extinction during the Late Pleisotocene (Martin, 1967;1990) although there were other contributing factors, like climate change (Nagaoka et al, 2018). With the long history of conservation work using fossils-often published in many disciplines like environmental geology, historical geology, paleoecology, and micropaleontology-it was just a matter of time that conservation paleobiology, as a discipline, was coined.…”

Lessons of 15,000 Years of Human–Wildlife Interaction for Conservation in Patagonia in the 21st Century

“…In the Americas, the late Pleistocene extinction of megafauna was severe and occurred at the same time of significant climate changes and human colonization, so the debate on the causes of extinction has been more controversial and persistent than in other continents. While the role of humans versus climate and other causes has been debated for almost 50 years in North America [14][15][16][17], few researchers, especially among archeologists, considered that humans had played a major role in South America until relatively recently (reviewed by [18]). This view has shifted in recent years, mainly due to paleoecological and paleontological studies increasingly assigning a possible major role to humans and concluding that more than one factor may be responsible for most extinctions [6,11,18].…”