Dicranopteris-dominated understory as major driver of intensive forest ecosystem in humid subtropical and tropical region

Dicranopteris is a common fern distributed throughout tropical and subtropical regions of the world. It often forms a mat-like understory, especially in open areas. A forest floor dominated by Dicranopteris plays an important role in ecosystem dynamics, but is often overlooked in ecological research. We conducted an experiment by removing overstory or understory Dicranopteris to compare their effects on soil microclimate, litter decomposition, soil decomposer food web and ecosystem nutrient cycling. Results of our field study showed that removal of a Dicranopteris-dominated understory leads to increased soil temperature and reduced soil moisture, subsequently, altering the components of the soil food web (microbial community, nematode and microarthropod densities) and reducing ecosystem processes of litter decomposition. When present, Dicranopteris forms a dense understory layer in subtropical and tropical regions, which is favorable for sustaining soil microclimates and acts as the major driver of soil biota and ecological processes in intensive forest ecosystems. ► Understory removal changed soil decomposer communities and litter decomposition. ► Understory removal increased soil temperature and reduced soil moisture. ► The effects of understory removal were more pronounced than canopy tree removal. ► Soil microclimates change may be responsible for changes of other measured variables. ► Dicranopteris-dominated understory is a major driver of intensive forest ecosystem.