4.3 Predominant factors governing bacterial, fungal, and protist
communities
Soil C, N, and P were strongly linked to Proteobacteria, Acidobacteria,
Ascomycota, and Cercozoa (Fig. 5). Nutrient cycling‒related
Proteobacteria and Acidobacteria are copiotrophic and oligotrophic,
respectively, and are sensitive to changes in nutrient levels (Ai et
al., 2015; Fierer et al., 2007). Increasing soil C and N availability
stimulates Proteobacteria growth whereas Acidobacteria prefer to live
under nutrient-poor conditions (Ai et al., 2015; Dai et al., 2018;
Fierer et al., 2012). Ascomycota are free-living saprotrophic fungi that
are involved in organic matter decomposition and regulate resource
availability (Baldrian et al., 2011; Chen et al., 2021). Here,
Proteobacteria, Acidobacteria, Ascomycota, and Cercozoa were the
dominant taxa and played important roles in modulating the soil C, N,
and P nutrient content.
In this study, temperature, vegetation type, and soil properties
markedly influenced the composition of bacterial, fungal, and protist
communities. Temperature was the key climate factor affecting bacterial
and fungal community composition. Bacterial and fungal activity
increased with soil temperature in the range of 5–30 °C
(BÁRcenas-Moreno et al., 2009; Pettersson and Bååth, 2003; Pietikainen
et al., 2005). The increased in soil temperature improved the growth of
certain bacterial and fungal taxa, thereby altering bacterial and fungal
community composition. Fungi, such
as mycorrhizal fungi form
beneficial mutualistic association with the roots of their plant host
(Johnson et al., 2004; Smith and Read, 2010).
Compared with bacterial community
composition, fungal community composition was more strongly affected by
vegetation type. However, protist
community composition was more sensitive to vegetation type and soil
physicochemistry than it was to
soil temperature. These discoveries confirm those of previous studies
reporting that differences in precipitation rate and water availability
rather than changes in soil temperature were limiting factors
influencing protist abundance (Stefan et al., 2014). Taken together,
temperature and vegetation were
the primary factors for predicting the changes in bacterial and fungal
community composition, while vegetation and soil property are the main
determinants of protist taxa.