The period between the late-Pleistocene glacial maximum and the early-Holocene thermal maximum (ca.21-7 cal ka) was a time of dramatic environmental change and biotic adjustments. The creation of new ecosystems in deglaciated regions was governed by the rate of ice recession, the nature of postglacial climate change, the characteristics of new landscapes, and the life-history traits of the biologic colonizers. The Yellowstone region supported the largest independent ice field in the western U.S., and ice recession after 17 cal ka set in motion a sequence of poorly-documented biologic events that ultimately led to the present-day terrestrial and aquatic ecosystems.
The proposed examination of the late-glacial and early-Holocene periods in the Yellowstone region brings forth decades of paleoenvironmental research, state of-the-art approaches in paleoecologic and hydroclimatic research, and improved radiocarbon dating. Yellowstone is an ideal region to examine the development and structuring of terrestrial and aquatic ecosystems, because (1) the climate history of the western US is reasonably well understood from prior data syntheses and paleoclimate model simulations; (2) a well-documented glacial history of the Yellowstone region offers independent information on local environmental change; (3) different substrates and precipitation regimes shape modern ecosystem distributions and likely have in the past as well; and (4) previous paleoecologic findings inspire the next generation of hypotheses that will be tested with new high-resolution records.