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Peter J. Wagner - One of the best experts on this subject based on the ideXlab platform.
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Extinction trajectories of benthic organisms across the triassic jurassic boundary
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Wolfgang Kiessling, Martin Aberhan, Benjamin Brenneis, Peter J. WagnerAbstract:Abstract We analysed diversity and abundance patterns of benthic organisms across the Triassic–Jurassic (T-J) boundary based on the Paleobiology Database (PBDB), which compiles palaeontological collection data on a global scale. While Sepkoski's [Sepkoski, J.J. Jr., 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363, 1–563] compendium on the stratigraphic ranges of marine animal genera suggests that the dominant macrobenthic groups of the Late Triassic experienced significant Extinctions prior to the T-J boundary, a significant end-Triassic Extinction peak is evident from PBDB's data. This Rhaetian Extinction peak is found in both an analysis of the raw data of stratigraphic ranges and a sample-standardized analysis of occurrence data; 41% of all mesobenthic and macrobenthic genera crossing the Norian–Rhaetian boundary became extinct within the Rhaetian. Although this rate suffices to characterize the end-Triassic Extinction as a true mass Extinction against a Middle Triassic to Middle Jurassic background, significantly reduced Rhaetian origination rates add to the strong diversity depletion in the earliest Jurassic. As for other mass Extinctions, evidence for selective Extinction is meagre when the analysis is limited to the boundary interval alone and when focused on taxonomic and ecological characteristics of individual genera. When taxa are separated by environmental preferences, however, several determinants of Extinction risk become evident, suggesting that reef dwellers had a significantly higher Extinction risk than level-bottom dwellers, taxa with an inshore preference were more strongly affected than offshore taxa, taxa preferring carbonate substrates were more strongly hit than taxa preferring siliciclastic substrates and taxa preferentially inhabiting low latitudes had higher Extinction rates than taxa more common at intermediate and high latitudes. Much of this selectivity is not independent and also seen in the intervals of background Extinctions suggesting that the end-Triassic mass Extinction represents an intensification of background Extinctions but not a qualitatively different macroevolutionary regime. One possible exception is related to preferences for depositional environments suggesting a selective Rhaetian Extinction in reefs and inshore settings.
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Extinction trajectories of benthic organisms across the Triassic–Jurassic boundary
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Wolfgang Kiessling, Martin Aberhan, Benjamin Brenneis, Peter J. WagnerAbstract:Abstract We analysed diversity and abundance patterns of benthic organisms across the Triassic–Jurassic (T-J) boundary based on the Paleobiology Database (PBDB), which compiles palaeontological collection data on a global scale. While Sepkoski's [Sepkoski, J.J. Jr., 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363, 1–563] compendium on the stratigraphic ranges of marine animal genera suggests that the dominant macrobenthic groups of the Late Triassic experienced significant Extinctions prior to the T-J boundary, a significant end-Triassic Extinction peak is evident from PBDB's data. This Rhaetian Extinction peak is found in both an analysis of the raw data of stratigraphic ranges and a sample-standardized analysis of occurrence data; 41% of all mesobenthic and macrobenthic genera crossing the Norian–Rhaetian boundary became extinct within the Rhaetian. Although this rate suffices to characterize the end-Triassic Extinction as a true mass Extinction against a Middle Triassic to Middle Jurassic background, significantly reduced Rhaetian origination rates add to the strong diversity depletion in the earliest Jurassic. As for other mass Extinctions, evidence for selective Extinction is meagre when the analysis is limited to the boundary interval alone and when focused on taxonomic and ecological characteristics of individual genera. When taxa are separated by environmental preferences, however, several determinants of Extinction risk become evident, suggesting that reef dwellers had a significantly higher Extinction risk than level-bottom dwellers, taxa with an inshore preference were more strongly affected than offshore taxa, taxa preferring carbonate substrates were more strongly hit than taxa preferring siliciclastic substrates and taxa preferentially inhabiting low latitudes had higher Extinction rates than taxa more common at intermediate and high latitudes. Much of this selectivity is not independent and also seen in the intervals of background Extinctions suggesting that the end-Triassic mass Extinction represents an intensification of background Extinctions but not a qualitatively different macroevolutionary regime. One possible exception is related to preferences for depositional environments suggesting a selective Rhaetian Extinction in reefs and inshore settings.
Mark E. Patzkowsky - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic Clustering of Origination and Extinction across the Late Ordovician Mass Extinction
PloS one, 2015Co-Authors: Andrew Z. Krug, Mark E. PatzkowskyAbstract:Mass Extinctions can have dramatic effects on the trajectory of life, but in some cases the effects can be relatively small even when Extinction rates are high. For example, the Late Ordovician mass Extinction is the second most severe in terms of the proportion of genera eliminated, yet is noted for the lack of ecological consequences and shifts in clade dominance. By comparison, the end-Cretaceous mass Extinction was less severe but eliminated several major clades while some rare surviving clades diversified in the Paleogene. This disconnect may be better understood by incorporating the phylogenetic relatedness of taxa into studies of mass Extinctions, as the factors driving Extinction and recovery are thought to be phylogenetically conserved and should therefore promote both origination and Extinction of closely related taxa. Here, we test whether there was phylogenetic selectivity in Extinction and origination using brachiopod genera from the Middle Ordovician through the Devonian. Using an index of taxonomic clustering (RCL) as a proxy for phylogenetic clustering, we find that A) both Extinctions and originations shift from taxonomically random or weakly clustered within families in the Ordovician to strongly clustered in the Silurian and Devonian, beginning with the recovery following the Late Ordovician mass Extinction, and B) the Late Ordovician mass Extinction was itself only weakly clustered. Both results stand in stark contrast to Cretaceous-Cenozoic bivalves, which showed significant levels of taxonomic clustering of Extinctions in the Cretaceous, including strong clustering in the mass Extinction, but taxonomically random Extinctions in the Cenozoic. The contrasting patterns between the Late Ordovician and end-Cretaceous events suggest a complex relationship between the phylogenetic selectivity of mass Extinctions and the long-term phylogenetic signal in origination and Extinction patterns.
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The stratigraphy of mass Extinction
Palaeontology, 2015Co-Authors: Steven M. Holland, Mark E. PatzkowskyAbstract:Patterns of last occurrences of fossil species are often used to infer the tempo and timing of mass Extinction, even though last occurrences generally precede the time of Extinction. Numerical simulations with constant Extinction demonstrate that last occurrences are not randomly distributed, but tend to cluster at subaerial unconformities, surfaces of forced regression, flooding surfaces and intervals of stratigraphical condensation, all of which occur in predictable stratigraphical positions. This clustering arises not only from hiatuses and non-deposition, but also from changes in water depth. Simulations with intervals of elevated Extinction cause such clusters of last occurrences to be enhanced within and below the interval of Extinction, suggesting that the timing and magnitude of Extinctions in these instances could be misinterpreted. With the possible exception of the end-Cretaceous, mass Extinctions in the fossil record are characterized by clusters of last occurrences at these sequence stratigraphical horizons. Although these clusters of last occurrences may represent brief pulses of elevated Extinction, they are equally likely to form by stratigraphical processes during a protracted period (more than several hundred thousand years) of elevated Extinction rate. Geochemical proxies of Extinction causes are also affected similarly, suggesting that many local expressions of mass Extinction should be re-evaluated for the timing of Extinction and its relation to environmental change. We propose three tests for distinguishing pulses of Extinction from clusters of last occurrences produced by stratigraphical processes.
Wolfgang Kiessling - One of the best experts on this subject based on the ideXlab platform.
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Extinction trajectories of benthic organisms across the triassic jurassic boundary
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Wolfgang Kiessling, Martin Aberhan, Benjamin Brenneis, Peter J. WagnerAbstract:Abstract We analysed diversity and abundance patterns of benthic organisms across the Triassic–Jurassic (T-J) boundary based on the Paleobiology Database (PBDB), which compiles palaeontological collection data on a global scale. While Sepkoski's [Sepkoski, J.J. Jr., 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363, 1–563] compendium on the stratigraphic ranges of marine animal genera suggests that the dominant macrobenthic groups of the Late Triassic experienced significant Extinctions prior to the T-J boundary, a significant end-Triassic Extinction peak is evident from PBDB's data. This Rhaetian Extinction peak is found in both an analysis of the raw data of stratigraphic ranges and a sample-standardized analysis of occurrence data; 41% of all mesobenthic and macrobenthic genera crossing the Norian–Rhaetian boundary became extinct within the Rhaetian. Although this rate suffices to characterize the end-Triassic Extinction as a true mass Extinction against a Middle Triassic to Middle Jurassic background, significantly reduced Rhaetian origination rates add to the strong diversity depletion in the earliest Jurassic. As for other mass Extinctions, evidence for selective Extinction is meagre when the analysis is limited to the boundary interval alone and when focused on taxonomic and ecological characteristics of individual genera. When taxa are separated by environmental preferences, however, several determinants of Extinction risk become evident, suggesting that reef dwellers had a significantly higher Extinction risk than level-bottom dwellers, taxa with an inshore preference were more strongly affected than offshore taxa, taxa preferring carbonate substrates were more strongly hit than taxa preferring siliciclastic substrates and taxa preferentially inhabiting low latitudes had higher Extinction rates than taxa more common at intermediate and high latitudes. Much of this selectivity is not independent and also seen in the intervals of background Extinctions suggesting that the end-Triassic mass Extinction represents an intensification of background Extinctions but not a qualitatively different macroevolutionary regime. One possible exception is related to preferences for depositional environments suggesting a selective Rhaetian Extinction in reefs and inshore settings.
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Extinction trajectories of benthic organisms across the Triassic–Jurassic boundary
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Wolfgang Kiessling, Martin Aberhan, Benjamin Brenneis, Peter J. WagnerAbstract:Abstract We analysed diversity and abundance patterns of benthic organisms across the Triassic–Jurassic (T-J) boundary based on the Paleobiology Database (PBDB), which compiles palaeontological collection data on a global scale. While Sepkoski's [Sepkoski, J.J. Jr., 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363, 1–563] compendium on the stratigraphic ranges of marine animal genera suggests that the dominant macrobenthic groups of the Late Triassic experienced significant Extinctions prior to the T-J boundary, a significant end-Triassic Extinction peak is evident from PBDB's data. This Rhaetian Extinction peak is found in both an analysis of the raw data of stratigraphic ranges and a sample-standardized analysis of occurrence data; 41% of all mesobenthic and macrobenthic genera crossing the Norian–Rhaetian boundary became extinct within the Rhaetian. Although this rate suffices to characterize the end-Triassic Extinction as a true mass Extinction against a Middle Triassic to Middle Jurassic background, significantly reduced Rhaetian origination rates add to the strong diversity depletion in the earliest Jurassic. As for other mass Extinctions, evidence for selective Extinction is meagre when the analysis is limited to the boundary interval alone and when focused on taxonomic and ecological characteristics of individual genera. When taxa are separated by environmental preferences, however, several determinants of Extinction risk become evident, suggesting that reef dwellers had a significantly higher Extinction risk than level-bottom dwellers, taxa with an inshore preference were more strongly affected than offshore taxa, taxa preferring carbonate substrates were more strongly hit than taxa preferring siliciclastic substrates and taxa preferentially inhabiting low latitudes had higher Extinction rates than taxa more common at intermediate and high latitudes. Much of this selectivity is not independent and also seen in the intervals of background Extinctions suggesting that the end-Triassic mass Extinction represents an intensification of background Extinctions but not a qualitatively different macroevolutionary regime. One possible exception is related to preferences for depositional environments suggesting a selective Rhaetian Extinction in reefs and inshore settings.
Willis Eschenbach - One of the best experts on this subject based on the ideXlab platform.
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historical bird and terrestrial mammal Extinction rates and causes
Diversity and Distributions, 2012Co-Authors: Craig Loehle, Willis EschenbachAbstract:Aim Conservation of species is an ongoing concern. Location Worldwide. Methods We examined historical Extinction rates for birds and mammals and contrasted island and continental Extinctions. Australia was included as an island because of its isolation. Results Only six continental birds and three continental mammals were recorded in standard databases as going extinct since 1500 compared to 123 bird species and 58 mammal species on islands. Of the Extinctions, 95% were on islands. On a per unit area basis, the Extinction rate on islands was 177 times higher for mammals and 187 times higher for birds than on continents. The continental mammal Extinction rate was between 0.89 and 7.4 times the background rate, whereas the island mammal Extinction rate was between 82 and 702 times background. The continental bird Extinction rate was between 0.69 and 5.9 times the background rate, whereas for islands it was between 98 and 844 times the background rate. Undocumented prehistoric Extinctions, particularly on islands, amplify these trends. Island Extinction rates are much higher than continental rates largely because of introductions of alien predators (including man) and diseases. Main conclusions Our analysis suggests that conservation strategies for birds and mammals on continents should not be based on island Extinction rates and that on islands the key factor to enhance conservation is to alleviate pressures from uncontrolled hunting and predation.
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research historical bird and terrestrial mammal Extinction rates and causes
2011Co-Authors: Craig Loehle, Willis EschenbachAbstract:Aim Conservation of species is an ongoing concern. Location Worldwide. Methods We examined historical Extinction rates for birds and mammals and contrasted island and continental Extinctions. Australia was included as an island because of its isolation. Results Only six continental birds and three continental mammals were recorded in standard databases as going extinct since 1500 compared to 123 bird species and 58 mammal species on islands. Of the Extinctions, 95% were on islands. On a per unit area basis, the Extinction rate on islands was 177 times higher for mammals and 187 times higher for birds than on continents. The continental mammal Extinction rate was between 0.89 and 7.4 times the background rate, whereas the island mammal Extinction rate was between 82 and 702 times background. The continental bird Extinction rate was between 0.69 and 5.9 times the background rate, whereas for islands it was between 98 and 844 times the background rate. Undocumented prehistoric Extinctions, particularly on islands, amplify these trends. Island Extinction rates are much higher than continental rates largely because of introductions of alien predators (including man) and diseases. Main conclusions Our analysis suggests that conservation strategies for birds and mammals on continents should not be based on island Extinction rates and that on islands the key factor to enhance conservation is to alleviate pressures from uncontrolled hunting and predation.
Martin Aberhan - One of the best experts on this subject based on the ideXlab platform.
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Extinction trajectories of benthic organisms across the triassic jurassic boundary
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Wolfgang Kiessling, Martin Aberhan, Benjamin Brenneis, Peter J. WagnerAbstract:Abstract We analysed diversity and abundance patterns of benthic organisms across the Triassic–Jurassic (T-J) boundary based on the Paleobiology Database (PBDB), which compiles palaeontological collection data on a global scale. While Sepkoski's [Sepkoski, J.J. Jr., 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363, 1–563] compendium on the stratigraphic ranges of marine animal genera suggests that the dominant macrobenthic groups of the Late Triassic experienced significant Extinctions prior to the T-J boundary, a significant end-Triassic Extinction peak is evident from PBDB's data. This Rhaetian Extinction peak is found in both an analysis of the raw data of stratigraphic ranges and a sample-standardized analysis of occurrence data; 41% of all mesobenthic and macrobenthic genera crossing the Norian–Rhaetian boundary became extinct within the Rhaetian. Although this rate suffices to characterize the end-Triassic Extinction as a true mass Extinction against a Middle Triassic to Middle Jurassic background, significantly reduced Rhaetian origination rates add to the strong diversity depletion in the earliest Jurassic. As for other mass Extinctions, evidence for selective Extinction is meagre when the analysis is limited to the boundary interval alone and when focused on taxonomic and ecological characteristics of individual genera. When taxa are separated by environmental preferences, however, several determinants of Extinction risk become evident, suggesting that reef dwellers had a significantly higher Extinction risk than level-bottom dwellers, taxa with an inshore preference were more strongly affected than offshore taxa, taxa preferring carbonate substrates were more strongly hit than taxa preferring siliciclastic substrates and taxa preferentially inhabiting low latitudes had higher Extinction rates than taxa more common at intermediate and high latitudes. Much of this selectivity is not independent and also seen in the intervals of background Extinctions suggesting that the end-Triassic mass Extinction represents an intensification of background Extinctions but not a qualitatively different macroevolutionary regime. One possible exception is related to preferences for depositional environments suggesting a selective Rhaetian Extinction in reefs and inshore settings.
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Extinction trajectories of benthic organisms across the Triassic–Jurassic boundary
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Wolfgang Kiessling, Martin Aberhan, Benjamin Brenneis, Peter J. WagnerAbstract:Abstract We analysed diversity and abundance patterns of benthic organisms across the Triassic–Jurassic (T-J) boundary based on the Paleobiology Database (PBDB), which compiles palaeontological collection data on a global scale. While Sepkoski's [Sepkoski, J.J. Jr., 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363, 1–563] compendium on the stratigraphic ranges of marine animal genera suggests that the dominant macrobenthic groups of the Late Triassic experienced significant Extinctions prior to the T-J boundary, a significant end-Triassic Extinction peak is evident from PBDB's data. This Rhaetian Extinction peak is found in both an analysis of the raw data of stratigraphic ranges and a sample-standardized analysis of occurrence data; 41% of all mesobenthic and macrobenthic genera crossing the Norian–Rhaetian boundary became extinct within the Rhaetian. Although this rate suffices to characterize the end-Triassic Extinction as a true mass Extinction against a Middle Triassic to Middle Jurassic background, significantly reduced Rhaetian origination rates add to the strong diversity depletion in the earliest Jurassic. As for other mass Extinctions, evidence for selective Extinction is meagre when the analysis is limited to the boundary interval alone and when focused on taxonomic and ecological characteristics of individual genera. When taxa are separated by environmental preferences, however, several determinants of Extinction risk become evident, suggesting that reef dwellers had a significantly higher Extinction risk than level-bottom dwellers, taxa with an inshore preference were more strongly affected than offshore taxa, taxa preferring carbonate substrates were more strongly hit than taxa preferring siliciclastic substrates and taxa preferentially inhabiting low latitudes had higher Extinction rates than taxa more common at intermediate and high latitudes. Much of this selectivity is not independent and also seen in the intervals of background Extinctions suggesting that the end-Triassic mass Extinction represents an intensification of background Extinctions but not a qualitatively different macroevolutionary regime. One possible exception is related to preferences for depositional environments suggesting a selective Rhaetian Extinction in reefs and inshore settings.
