Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wang, S. C. Articles by Bush, A. M. Search for Related Content GeoRef GeoRef Citation

Adjusting global extinction rates to account for taxonomic susceptibility

¹ Steve C. Wang. Department of Mathematics and Statistics, Swarthmore College, Swarthmore, Pennsylvania 19081. scwang{at}swarthmore.edu
² Andrew M. Bush. Department of Ecology and Evolutionary Biology and Center for Integrative Geosciences, University of Connecticut, 75 North Eagleville Rd, Unit 3043, Storrs, Connecticut 06269. andrew.bush{at}uconn.edu

Studies of extinction in the fossil record commonly involve comparisons of taxonomic extinction rates, often expressed as the percentage of taxa (e.g., families or genera) going extinct in a time interval. Such extinction rates may be influenced by factors that do not reflect the intrinsic severity of an extinction trigger. Two identical triggering events (e.g., bolide impacts, sea level changes, volcanic eruptions) could lead to different taxonomic extinction rates depending on factors specific to the time interval in which they occur, such as the susceptibility of the fauna or flora to extinction, the stability of food webs, the positions of the continents, and so on. Thus, it is possible for an extinction event with a higher taxonomic extinction rate to be caused by an intrinsically less severe trigger, compared to an event with a lower taxonomic extinction rate.

Here, we isolate the effects of taxonomic susceptibility on extinction rates. Specifically, we quantify the extent to which the taxonomic extinction rate in a substage is elevated or depressed by the vulnerability to extinction of classes extant in that substage. Using a logistic regression model, we estimate that the taxonomic susceptibility of marine fauna to extinction has generally declined through the Phanerozoic, and we adjust the observed extinction rate in each substage to estimate the intrinsic extinction severity more accurately. We find that mass extinctions do not generally occur during intervals of unusually high susceptibility, although susceptibility sometimes increases in post-extinction recovery intervals. Furthermore, the susceptibility of specific animal classes to extinction is generally similar in times of background and mass extinction, providing no evidence for differing regimes of extinction selectivity. Finally, we find an inverse correlation between extinction rate within substages and the evenness of diversity of major taxonomic groups, but further analyses indicate that low evenness itself does not cause high rates of extinction.

This article has been cited by other articles:

				C. Simpson and P. G. Harnik Assessing the role of abundance in marine bivalve extinction over the post-Paleozoic Paleobiology, December 1, 2009; 35(4): 631 - 647. [Abstract] [Full Text] [PDF]

				K. Roy, G. Hunt, and D. Jablonski Phylogenetic Conservatism of Extinctions in Marine Bivalves Science, August 7, 2009; 325(5941): 733 - 737. [Abstract] [Full Text] [PDF]