Protist ecology in Patagonian peatlands: pH, organic phosphorus, and sulfate as key drivers of testate amoeba diversity in undisturbed ecosystems

Peatlands in southern Chile, particularly in the remote Aysén region, provide unique ecosystems that remain understudied despite their ecological significance. Testate amoebae, a group of shelled protists, are important components of these ecosystems due to their roles in nutrient cycling and their sensitivity to environmental changes, which make them valuable bioindicators. However, research on the ecological drivers shaping their diversity and community composition in Chilean peatlands remains scarce. This study investigates the spatial distribution and diversity of testate amoebae across five peatlands in the Aysén region. By analyzing environmental variables such as pH, dissolved organic carbon, and sulfate, we identify key factors influencing community structure. Our findings highlight significant spatial turnover in testate amoeba communities, suggesting that local environmental gradients strongly shape their distribution. Notably, the Sphagnum -dominated peatlands exhibit higher diversity compared to mixed vegetation peatlands. The redundancy analysis reveals that organic phosphorus, pH, and sulfate are the most influential variables affecting testate amoeba communities. This study fills a critical gap in the understanding of microbial biodiversity in Chilean peatlands and underscores the importance of conserving these near-pristine ecosystems as reservoirs of microbial diversity and natural archives of environmental change.