Comparing Species Diversity in the Modern and Fossil Record of Lakes

Abstract

Lake faunal diversity has been the focus of many modern studies; however, there have been few studies comparing the lacustrine diversity in the modern and fossil record. Whether or not this comparison is possible is dependent on preservation. By comparing the exceptional preservation of the Konservat Lagerstätten of the Eocene Green River Formation with its various modern analogs in East Africa, unique factors controlling diversity within a lake system can be determined. Such factors would include lake surface area, lake longevity, productivity, and lake type. In order to effectively compare lake diversity in the modern and fossil record, we first estimated the potential preservational bias of the fauna from modern Lake Tanganyika and determined that, at maximum, approximately 43.8% of species, 59.3% of genera, and 65.8% of families would be identifiable. With this taphonomic filter in place, we compared fish species diversity versus lake area; no strong relationship was found. Faunal species diversity versus lake longevity was shown to correlate in long‐lived lakes both in a modern and geologic context. When including modern lakes into this comparison, the correlation is not as strong, possibly because of the limited life span of these lakes. Lake Tanganyika was comparable to lakes in the geologic record, after the taphonomic filter was applied. Finally, to test the relationship between species and lake type and productivity, the underfilled, balanced‐filled, and overfilled lake basin model of Carroll, Bohacs, and coworkers was used as a basis for comparison between the fauna found in lake deposits within the Green River Formation and modern lakes from East Africa.