A Review and Synthesis of Late Pleistocene Extinction Modeling: Progress Delayed by Mismatches between Ecological Realism, Interpretation, and Methodological Transparency

Abstract

Late Pleistocene extinctions occurred globally over a period of about 50,000 years, primarily affecting mammals of > or = 44 kg body mass (i.e., megafauna) first in Australia, continuing in Eurasia and, finally, in the Americas. Polarized debate about the cause(s) of the extinctions centers on the role of climate change and anthropogenic factors (especially hunting). Since the late 1960s, investigators have developed mathematical models to simulate the ecological interactions that might have contributed to the extinctions. Here, we provide an overview of the various methodologies used and conclusions reached in the modeling literature, addressing both the strengths and weaknesses of modeling as an explanatory tool. Although late Pleistocene extinction models now provide a solid foundation for viable future work, we conclude, first, that single models offer less compelling support for their respective explanatory hypotheses than many realize; second, that disparities in methodology (both in terms of model parameterization and design) prevent meaningful comparison between models and, more generally, progress from model to model in increasing our understanding of these extinctions; and third, that recent models have been presented and possibly developed without sufficient regard for the transparency of design that facilitates scientific progress.

Robustness despite uncertainty: regional climate data reveal the dominant role of humans in explaining global extinctions of Late Quaternary megafauna

“…Two broad drivers of extinction have been proposed and extensively debated: Late Pleistocene and Holocene climatic change, or the arrival of anatomically modern humans (Grayson and Meltzer , Fiedel and Haynes , Burney and Flannery , Koch and Barnosky , Wroe and Field , Wroe et al , Ugan and Byers , Pushkina and Raia , Nogués‐Bravo et al , Haynes ). Despite five decades of research and debate (Leakey , , Martin , ), the relative importance of these drivers across the globe remains contentious (Boulanger and Lyman , Flores , Lima‐Ribeiro and Diniz‐Filho , Yule et al ).…”

“…these drivers across the globe remains contentious (Boulanger and Lyman 2014, Flores 2014, Lima-Ribeiro and Diniz-Filho 2014, Yule et al 2014.…”

Modelling effects of disturbance on population dynamics of generalized crayfish life history strategies

“…Accordingly, a trait‐based approach might allow PVAs to be more broadly applied within conservation and management programmes of data‐sparse species. However, the wide variety of modelling techniques, lack of transparency in model construction, and the inability to realistically compare highly divergent taxonomic groups or observational scales still limit the generalizability of many existing modelling frameworks (Yule et al, 2014). Simple models can advance research in data‐scarce systems by providing a generalizable baseline upon which future, more tailored modelling efforts can be built.…”

Pleistocene Overkill and North American Mammalian Extinctions

“…The simulations (e.g., Alroy 2001a, Brook & Bowman 2004, Bulte et al 2006, Mosimann & Martin 1975, Zuo et al 2013 are built around a core set of variables, notably prey population density and growth rates, human population density, and prey harvest rate (Yule et al 2014). The challenge is assigning values to those variables and determining the weight of factors such as prey naiveté, competitive relationships, initial human population size, growth rates, and hunting skill.…”

“…Perhaps not surprisingly, the results vary as to which genera go extinct and which survive and what variables (e.g., body size, life history traits) are more relevant in driving the outcome (Yule et al 2014). Moreover, "simulation studies will conceal regional and local responses to various parameters, as well as subtle interplay at fine spatial and temporal scales" (Roberts 2014, p. 143; see also Bliege Bird 2015).…”