Modern coprophilous fungal spores and their ecological indication from lakes in the Inner Mongolia steppe and surrounding areas

Abstract

Modern process studies of coprophilous fungal spores are crucial for better interpreting the fossil records. However, studies investigating the distribution and assemblages of these spores in lake surface sediments remains relatively sparse in northern China, a region where pastoralism constitutes the primary subsistence strategy. Here, 44 lake surface sediment samples were collected in the Inner Mongolia steppe and its surrounding areas, and the characteristics and ecological significance of coprophilous fungal spores were discussed for the first time. The results showed that a total of 40 fungal spore types were identified from the modern samples, including 11 common coprophilous fungal spore types dominated by Sporormiella-type, Sordaria spp., Coniochaeta cf. ligniaria, and Coniochaeta sp.. The samples of shrub vegetation areas contained the highest abundance of coprophilous fungal spores, followed by the samples of cultivated vegetation, meadow vegetation, and steppe vegetation areas, while the samples of desert and broad-leaved forest vegetation areas showed the lowest abundance. The results of grouping analysis and non-parametric tests found that the combined abundance of Sporormiella-type, Sordaria spp., Delitschia spp., Podospora sp., Coniochaeta sp., Cercophora sp., and Arnium sp. provides a more reliable indicator of regional grazing intensity in the region. This study clarifies the indication of coprophilous fungal spores on grazing intensity in the Inner Mongolia steppe and its surrounding areas, and provides a theoretical basis for further research on past grazing intensity and pastoralism history from lake sediments in the region.