Landscapes, large animals, and palynological proxies

By including spore counts of the dung fungus, Sporormiella spp., pollen studies can now broaden their traditional focus to offer a proxy measure of the density of large animals on Quaternary landscapes. The addition of microscopic charcoal analysis may further reveal patterns of change in fire history. Taken together, this approach has led to plausible inferences regarding prehistoric interactions of human influence, grazing/browsing pressure, and climate change, at a landscape level. Such palynological proxy data suggest that human arrival in the New York/New Jersey region of eastern North America during the late Pleistocene was followed by megafaunal extinction and profound ecological change. Analysis of late Holocene deposits from the island of Madagascar reflect a similar sequence of events unfolding ten thousand years later, also in the wake of human arrival. In a further useful comparison, Sporormiella and other proxies trace the introduction of large domestic animals and other changes in human land use, first in Madagascar, and later in eastern North America. Sporormiella can also chronicle the introduction of terrestrial mammals to oceanic islands. A record from Lehua, about 31km west of Kauai, Hawaii, marks the point at which rabbits and rats transformed the island ecology. It is not certain if Sporormiella would detect a rat invasion alone, but it is clear that the large native seabird population of Lehua leaves no such signal.