Adjusting global extinction rates to account for taxonomic susceptibility

نویسندگان

  • Steve C. Wang
  • Andrew M. Bush
چکیده

—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. Steve C. Wang. Department of Mathematics and Statistics, Swarthmore College, Swarthmore, Pennsylvania 19081. E-mail: [email protected] 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. E-mail: [email protected] Accepted: 2 June 2008

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Rates of Species - Level Origination and Extinction : Functions of Age , Diversity , and History

Global-scale data on the Oligocene to Recent planktic foraminifers and coccoliths from the tropical Pacific and Atlantic Oceans are employed for quantitative testing of alternative models (Red Queen and Stationary Hypotheses) of the relationship between speciation rates, extinction rates, taxonomic diversity, abiotic events, and history of the paleosystem. The results demonstrate that although ...

متن کامل

Global Taxonomic Diversity of Anomodonts (Tetrapoda, Therapsida) and the Terrestrial Rock Record Across the Permian-Triassic Boundary

The end-Permian biotic crisis (~252.5 Ma) represents the most severe extinction event in Earth's history. This paper investigates diversity patterns in Anomodontia, an extinct group of therapsid synapsids ('mammal-like reptiles'), through time and in particular across this event. As herbivores and the dominant terrestrial tetrapods of their time, anomodonts play a central role in assessing the ...

متن کامل

Global Patterns of Extinction Risk in Marine and Non-marine Systems

Despite increasing concern over the effects of human activities on marine ecosystems, extinction in the sea remains scarce: 19-24 out of a total of >850 recorded extinctions implies a 9-fold lower marine extinction rate compared to non-marine systems. The extent of threats faced by marine systems, and their resilience to them, receive considerable attention, but the detectability of marine exti...

متن کامل

Accelerating extinction risk from climate change

Current predictions of extinction risks from climate change vary widely depending on the specific assumptions and geographic and taxonomic focus of each study. I synthesized published studies in order to estimate a global mean extinction rate and determine which factors contribute the greatest uncertainty to climate change–induced extinction risks. Results suggest that extinction risks will acc...

متن کامل

Climate change. Accelerating extinction risk from climate change.

Current predictions of extinction risks from climate change vary widely depending on the specific assumptions and geographic and taxonomic focus of each study. I synthesized published studies in order to estimate a global mean extinction rate and determine which factors contribute the greatest uncertainty to climate change-induced extinction risks. Results suggest that extinction risks will acc...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2008