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Where to Dig for Fossils: Combining Climate-Envelope, Taphonomy and Discovery Models.

Block S, Saltré F, Rodríguez-Rey M, Fordham DA, Unkel I, Bradshaw CJ - PLoS ONE (2016)

Bottom Line: The traditional fossil-hunting approach focuses on small areas and has not yet taken advantage of modelling techniques commonly used in ecology to account for an organism's past distributions.We demonstrate the utility of accounting for the distribution history of fossil taxa when trying to find the most suitable areas to look for fossils.We proposed potential areas to discover new fossils of Diprotodon, Zygomaturus, Protemnodon, Thylacoleo, and Genyornis, and provide guidelines on how to apply our approach to assist fossil hunting in other continents and geological settings.

View Article: PubMed Central - PubMed

Affiliation: The Environment Institute and School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia.

ABSTRACT
Fossils represent invaluable data to reconstruct the past history of life, yet fossil-rich sites are often rare and difficult to find. The traditional fossil-hunting approach focuses on small areas and has not yet taken advantage of modelling techniques commonly used in ecology to account for an organism's past distributions. We propose a new method to assist finding fossils at continental scales based on modelling the past distribution of species, the geological suitability of fossil preservation and the likelihood of fossil discovery in the field, and apply it to several genera of Australian megafauna that went extinct in the Late Quaternary. Our models predicted higher fossil potentials for independent sites than for randomly selected locations (mean Kolmogorov-Smirnov statistic = 0.66). We demonstrate the utility of accounting for the distribution history of fossil taxa when trying to find the most suitable areas to look for fossils. For some genera, the probability of finding fossils based on simple climate-envelope models was higher than the probability based on models incorporating current conditions associated with fossil preservation and discovery as predictors. However, combining the outputs from climate-envelope, preservation, and discovery models resulted in the most accurate predictions of potential fossil sites at a continental scale. We proposed potential areas to discover new fossils of Diprotodon, Zygomaturus, Protemnodon, Thylacoleo, and Genyornis, and provide guidelines on how to apply our approach to assist fossil hunting in other continents and geological settings.

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Related in: MedlinePlus

Effect of combining models on probability of finding fossils.Probability of finding a grid cell with independent fossil sites of five genera in areas predicted by the climate-envelope models (blue bars), in the area predicted by fossil preservation and discovery models (green bars), and in the area predicted by all models (i.e., climate-envelope, preservation, and discovery). Each probability is divided by the probability of finding the grid cells in all of Australia to emphasise usefulness of model combinations compared to finding fossils by chance. For example, a value of one (horizontal dashed line) would mean that the probability of finding a fossil using the model is the same as the probability of finding it by chance.
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pone.0151090.g002: Effect of combining models on probability of finding fossils.Probability of finding a grid cell with independent fossil sites of five genera in areas predicted by the climate-envelope models (blue bars), in the area predicted by fossil preservation and discovery models (green bars), and in the area predicted by all models (i.e., climate-envelope, preservation, and discovery). Each probability is divided by the probability of finding the grid cells in all of Australia to emphasise usefulness of model combinations compared to finding fossils by chance. For example, a value of one (horizontal dashed line) would mean that the probability of finding a fossil using the model is the same as the probability of finding it by chance.

Mentions: Averaging the output of the three models led to higher Kolmogorov-Smirnov values compared to estimates from separate models (S4 Table). The only exception was Diprotodon, for which the discovery model had a slightly higher median Kolmogorov-Smirnov statistic than the combined models (0.57 and 0.50, respectively). The probability of finding fossils of Diprotodon, Protemnodon, and Genyornis was higher in the overlapping areas suitable for fossil preservation and discovery, while it was higher in areas of suitable palaeo-climate for Zygomaturus and Thylacoleo (Fig 2). However, the highest probabilities for all genera were always where the three areas overlapped (S6 Fig).


Where to Dig for Fossils: Combining Climate-Envelope, Taphonomy and Discovery Models.

Block S, Saltré F, Rodríguez-Rey M, Fordham DA, Unkel I, Bradshaw CJ - PLoS ONE (2016)

Effect of combining models on probability of finding fossils.Probability of finding a grid cell with independent fossil sites of five genera in areas predicted by the climate-envelope models (blue bars), in the area predicted by fossil preservation and discovery models (green bars), and in the area predicted by all models (i.e., climate-envelope, preservation, and discovery). Each probability is divided by the probability of finding the grid cells in all of Australia to emphasise usefulness of model combinations compared to finding fossils by chance. For example, a value of one (horizontal dashed line) would mean that the probability of finding a fossil using the model is the same as the probability of finding it by chance.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814095&req=5

pone.0151090.g002: Effect of combining models on probability of finding fossils.Probability of finding a grid cell with independent fossil sites of five genera in areas predicted by the climate-envelope models (blue bars), in the area predicted by fossil preservation and discovery models (green bars), and in the area predicted by all models (i.e., climate-envelope, preservation, and discovery). Each probability is divided by the probability of finding the grid cells in all of Australia to emphasise usefulness of model combinations compared to finding fossils by chance. For example, a value of one (horizontal dashed line) would mean that the probability of finding a fossil using the model is the same as the probability of finding it by chance.
Mentions: Averaging the output of the three models led to higher Kolmogorov-Smirnov values compared to estimates from separate models (S4 Table). The only exception was Diprotodon, for which the discovery model had a slightly higher median Kolmogorov-Smirnov statistic than the combined models (0.57 and 0.50, respectively). The probability of finding fossils of Diprotodon, Protemnodon, and Genyornis was higher in the overlapping areas suitable for fossil preservation and discovery, while it was higher in areas of suitable palaeo-climate for Zygomaturus and Thylacoleo (Fig 2). However, the highest probabilities for all genera were always where the three areas overlapped (S6 Fig).

Bottom Line: The traditional fossil-hunting approach focuses on small areas and has not yet taken advantage of modelling techniques commonly used in ecology to account for an organism's past distributions.We demonstrate the utility of accounting for the distribution history of fossil taxa when trying to find the most suitable areas to look for fossils.We proposed potential areas to discover new fossils of Diprotodon, Zygomaturus, Protemnodon, Thylacoleo, and Genyornis, and provide guidelines on how to apply our approach to assist fossil hunting in other continents and geological settings.

View Article: PubMed Central - PubMed

Affiliation: The Environment Institute and School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia.

ABSTRACT
Fossils represent invaluable data to reconstruct the past history of life, yet fossil-rich sites are often rare and difficult to find. The traditional fossil-hunting approach focuses on small areas and has not yet taken advantage of modelling techniques commonly used in ecology to account for an organism's past distributions. We propose a new method to assist finding fossils at continental scales based on modelling the past distribution of species, the geological suitability of fossil preservation and the likelihood of fossil discovery in the field, and apply it to several genera of Australian megafauna that went extinct in the Late Quaternary. Our models predicted higher fossil potentials for independent sites than for randomly selected locations (mean Kolmogorov-Smirnov statistic = 0.66). We demonstrate the utility of accounting for the distribution history of fossil taxa when trying to find the most suitable areas to look for fossils. For some genera, the probability of finding fossils based on simple climate-envelope models was higher than the probability based on models incorporating current conditions associated with fossil preservation and discovery as predictors. However, combining the outputs from climate-envelope, preservation, and discovery models resulted in the most accurate predictions of potential fossil sites at a continental scale. We proposed potential areas to discover new fossils of Diprotodon, Zygomaturus, Protemnodon, Thylacoleo, and Genyornis, and provide guidelines on how to apply our approach to assist fossil hunting in other continents and geological settings.

Show MeSH
Related in: MedlinePlus