Testate Amoebae as Paleoclimatic Proxies in Rocky Mountain Peatlands: A Case Study in the Greater Yellowstone Ecosystem

Abstract

We investigated the potential of testate amoebae (Protozoa: Rhizopoda) for reconstructing past climate changes in the Rocky Mountain region. Our specific objectives were to determine environmental controls on modem testate amoeba distribution in Sphagnum-dominated peatlands of the region, reconstruct past temporal changes in testate amoebae from a Sphagnum-dominated peatland in southwestern Yellowstone National Park, and assess relationships between climate variability and testate amoebae for the past century. Our results indicate that substrate moisture is the dominant control on modem testate amoeba distribution in the region, consistent with studies from other regions. Temporal changes in testate amoebae reconstructed from a floating peat mat in the Greater Yellowstone Ecosystem show considerable variability during the past several hundred years, and variability during the past century was correlated with the instrumental record of drought at decadal timescales. The patterns suggest that sensitive paleoclimatic reconstructions are possible from floating mats in the region, and perhaps elsewhere. Testate amoebae from peatlands in the Rocky Mountains show great potential for reconstructing past climate variability, corroborating and extending records inferred from other proxies.