5. CONCLUSIONS
The present study revealed that soil bacteria, fungi, protists, and the food webs they form respond differently to vegetation type depending on the ambient temperature. We demonstrated that bacterial, fungal, and protist diversity and community composition differed under vegetation restoration and cropland. However, bacterial, fungal, and protist diversity and community composition were similar under plantation forest and shrubland because the soils under these vegetation types had similar nutrient profiles. There were significant differences in bacterial, fungal, and protist community composition between Guizhou (MAT, 14.6 °C) and Guangxi (MAT, 20.9 °C) because of the substantial temperature difference between these regions. The low temperature at Guizhou strengthened interspecific interactions among bacterial, fungal, and protist taxa. There might have been relatively greater bacterial diversity at Guizhou than at Guangxi. Similarly, high bacterial diversity in cropland soil caused to stronger interactions in the microbiome network under cropland than under plantation forest or shrubland. Hence, it is primarily bacteria that shape the co-occurrence networks among microbial taxa. The protist phyla Cercozoa and Lobosa prey upon the bacterial phyla Acidobacteria and Proteobacteria, and the fungal phylum Ascomycota. Proteobacteria, Acidobacteria, Ascomycota, and Cercozoa predominated in the karst and regulated the variations in the C, N, and P nutrient levels in the soils there. Bacterial and fungal community compositions were strongly affected by changing temperature and vegetation type whereas protist community composition was influenced mainly by vegetation type and soil properties. Taken together, these findings underscore the importance of evaluating the relationships among bacterial, fungal, and protist taxa during vegetation restoration. They also suggest that temperature must be considered in during soil nutrient cycling as microbial interactions are strongly influenced by it. Fungi were comparatively more dependent than bacteria on plant community. Nevertheless, in the present study, we did not compare plant diversity between plantation forest and shrubland. Future studies should integrate plant characteristics and examine the complex relationships among microorganisms and vegetation.