Relating environmental change and species stability in Late Ordovician seas

Abstract

Niche stability of a diverse suite of 21 invertebrate species and genera from the Cincinnatian Series (Katian Stage) of North America was examined using spatial distribution modeling across nine time slices, including abiotic and biotic environmental change. Niche stability varied through time. The focal taxa exhibited niche stability ( = no adaptive response) and tracked their preferred environment laterally to accommodate gradual sea-level fall. Niche evolution increased during the Richmondian Invasion. Species adjusted to the introduction of new competitors by contracting their niche into a subset of their previous niche parameters. In Cincinnatian species and genera, adaptive response (stability vs. evolution) was related to the tempo and mode of environmental change.