The puzzle of North America's Late Pleistocene megafaunal extinction patterns: Test of new explanation yields unexpected results

Yule, Jeffrey V.; Jensen, Christopher X. Jon; Joseph, Aby; Goode, Jimmie

doi:10.1016/j.ecolmodel.2008.10.023

Cited by 8 publications

(10 citation statements)

References 17 publications

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“…The absence of kill sites for most of these genera and paucity for others is also inconsistent with the alternative hypothesis; that humans rapidly drove all of these animals into extinction. Given the technology involved, along with several other significant problems (7,8), it is highly unlikely that humans rapidly triggered the extinction of so many genera on a continental scale, although human-caused extinction is well supported in the prehistoric record of vulnerable island animal populations (e.g., 7, 9, 10). More sophisticated models combining environmental and human induced causes (e.g., 11) are potentially viable for explaining singular mammal extinctions (e.g., Mammuthus), but fall short of explaining the full taxonomic depth and ecological breadth of the latest Pleistocene extinctions.…”

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confidence: 99%

Shock-synthesized hexagonal diamonds in Younger Dryas boundary sediments

Kennett¹,

Kennett²,

West³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

177

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The long-standing controversy regarding the late Pleistocene megafaunal extinctions in North America has been invigorated by a hypothesis implicating a cosmic impact at the Ållerød-Younger Dryas boundary or YDB (Ϸ12,900 ؎ 100 cal BP or 10,900 ؎ 100 14 C years). Abrupt ecosystem disruption caused by this event may have triggered the megafaunal extinctions, along with reductions in other animal populations, including humans. The hypothesis remains controversial due to absence of shocked minerals, tektites, and impact craters. Here, we report the presence of shock-synthesized hexagonal nanodiamonds (lonsdaleite) in YDB sediments dating to Ϸ12,950 ؎ 50 cal BP at Arlington Canyon, Santa Rosa Island, California. Lonsdaleite is known on Earth only in meteorites and impact craters, and its presence strongly supports a cosmic impact event, further strengthened by its co-occurrence with other nanometer-sized diamond polymorphs (n-diamonds and cubics). These shock-synthesized diamonds are also associated with proxies indicating major biomass burning (charcoal, carbon spherules, and soot). This biomass burning at the Younger Dryas (YD) onset is regional in extent, based on evidence from adjacent Santa Barbara Basin and coeval with broader continent-wide biomass burning. Biomass burning also coincides with abrupt sediment mass wasting and ecological disruption and the last known occurrence of pygmy mammoths (Mammuthus exilis) on the Channel Islands, correlating with broader animal extinctions throughout North America. The only previously known co-occurrence of nanodiamonds, soot, and extinction is the Cretaceous-Tertiary (K/T) impact layer. These data are consistent with abrupt ecosystem change and megafaunal extinction possibly triggered by a cosmic impact over North America at Ϸ12,900 ؎ 100 cal BP.Arlington Canyon ͉ biomass burning ͉ cosmic impact ͉ hexagonal nanodiamonds ͉ megafaunal extinctions

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mentioning

confidence: 99%

Shock-synthesized hexagonal diamonds in Younger Dryas boundary sediments

Kennett¹,

Kennett²,

West³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

177

View full text Add to dashboard Cite

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“…Critiques of model design (e.g., Ginzburg and Jensen 2004) suggest that the model may be overparameterized. Yule et al (2009) represents the first return to multiprey system modeling in North America following Alroy (2001). Yule et al (2009) simulates human predation on a subset of individually parameterized North American fauna in an allometrically constrained model.…”

Section: Aggregate Megafaunal Modelsmentioning

confidence: 99%

“…Yule et al (2009) represents the first return to multiprey system modeling in North America following Alroy (2001). Yule et al (2009) simulates human predation on a subset of individually parameterized North American fauna in an allometrically constrained model. Although the six-species prey assemblage is smaller than Alroy's (2001), selected species characterize a range of mass categories sufficient to overlap the mass threshold predictor of survival-extinction outcomes.…”

Section: Aggregate Megafaunal Modelsmentioning

confidence: 99%

“…In addition to allometrically defined parameters, the model also explores two unconstrained parameters: hunting pressure and prey susceptibility. Although functional response is considered to be critical for achieving ecologically realistic characterizations of predator-prey interactions both in general (e.g., Skalski and Gilliam 2001;Fenlon and Faddy 2006;Williams 2008) and in regard to late Pleistocene extinction modeling (e.g., Brook and Bowman 2002;Brook and Johnson 2006), Yule et al (2009) is one of the first modeling exercises to explore the conse-quences to predator-prey dynamics of varying functional response choice. Prior to Yule et al (2009), no multiprey models and only one single-prey model (Brook and Johnson 2006) tested the effect of varying functional response forms.…”

Section: Aggregate Megafaunal Modelsmentioning

confidence: 99%

“…Although functional response is considered to be critical for achieving ecologically realistic characterizations of predator-prey interactions both in general (e.g., Skalski and Gilliam 2001;Fenlon and Faddy 2006;Williams 2008) and in regard to late Pleistocene extinction modeling (e.g., Brook and Bowman 2002;Brook and Johnson 2006), Yule et al (2009) is one of the first modeling exercises to explore the conse-quences to predator-prey dynamics of varying functional response choice. Prior to Yule et al (2009), no multiprey models and only one single-prey model (Brook and Johnson 2006) tested the effect of varying functional response forms. Yule et al (2009) models system dynamics under three different functional response forms: Holling Type II; Beddington-DeAngelis (a simple derivative of the Holling Disc Equation incorporating a predator interference parameter, i, which provides a measure of the time spent by predators interacting with one another rather than hunting); and Ratio Dependence (which assumes complete sharing of prey among predators).…”

Section: Aggregate Megafaunal Modelsmentioning

confidence: 99%

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

Yule¹,

Fournier²,

Jensen³

et al. 2014

The Quarterly Review of Biology

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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.

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

Bayer

Fournier

Magoulick

2021

Aquatic Conservation

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Crayfish play a crucial ecological role and are often considered a keystone species within freshwater ecosystems; however, North American crayfish species face disturbance and ecological threats including invasive species and intensified drought. Demographic models can allow examination of population dynamics of a targeted species under a wide variety of disturbance scenarios. In this study, crayfish population dynamics were modelled and their responses to simulated biological invasions and drought were assessed. As life history data on crayfish are relatively rare, models were used to explore the population viability of four generalized species with distinct life history strategies under 11 disturbance scenarios. RAMAS‐Metapop was used to construct stage‐based demographic metapopulation models parameterized using vital rates from established literature sources. Models indicated that populations respond differentially to disturbance based on life history. However, both r‐ and K‐selected species appear to be highly susceptible to decline when faced with the additive effects of reduced carrying capacity resulting from invasion and reduced survival rates caused by drought. Constructing models that explore a broad array of life histories and disturbance regimes can provide managers with tools to develop generalized, widely applicable conservation strategies in data‐depauperate systems.

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The puzzle of North America's Late Pleistocene megafaunal extinction patterns: Test of new explanation yields unexpected results

Cited by 8 publications

References 17 publications

Shock-synthesized hexagonal diamonds in Younger Dryas boundary sediments

Shock-synthesized hexagonal diamonds in Younger Dryas boundary sediments

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

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

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