What Environmental Conditions do Testate Amoebas Prefer in the Peruvian Peatlands?

Abstract

Testate amoebae are a group of protozoa that live in aquatic environments such as peatlands, estuaries, and lakes, and their shells are often well-preserved in the sediments of these environments. These organisms are useful for reconstructing change in nutrient status and hydrology due to their sensitivity to pH, soil moisture, and water table depth (WTD). However, this method has seldom been applied to non Sphagnum-dominated peatland environments such as mountain fens. Here we present the first training set and transfer function from high Peruvian Andes cushion peatlands. These ecosystems are dominated by Distichia muscoides, a robust cushion-forming plant from the Juncaceae family. Fifty surface samples of Distichia peat were collected from six sites in the Cordillera Vilcanota, southeastern Peru, in summer 2017. Water table depth, conductivity, and pH were measured during sample collection; peat moisture was calculated in the lab using the difference between fresh and dry peat weights. After analyzing 20 of the 50 samples, a transfer function was generated on the basis of statistical relationships between each testate amoeba taxon and its environmental preferences. Preliminary results suggest that WTD is the main factor controlling testate amoebae communities at our sites. Our transfer function, which connects each testate amoeba taxon with its preferred WTD will be applied to reconstruct past hydrological changes across the region and provide a new means to better understand past climate change.