How does fire affect community assembly of tropical old-growth grasslands?

Abstract

Old-growth grasslands (OGG) are composed of a species-rich herbaceous layer that are maintained by endogenous disturbance - as frequent fires, and edaphic factors. Fire is a major ecological factor influencing plant community in these ecosystems, by favoring herbaceous species and limiting woody species. The plant community is thought to be dependent on fire, and consequently OGG conservation is threatened by fire exclusion, which alters the structure, physiognomies and biodiversity of the OGG. To better understand fire as an environmental driver in OGG plant community, we will analyze aboveground biomass and plant diversity of the herbaceous layer in different OGG in response to fire exclusion and different climate and soil conditions. We hypothesized that fire exclusion leads to an accumulation of aboveground biomass in plant communities, favoring woody encroachment, and a loss in biodiversity from the species-rich herbaceous layer. Our results will bring insights about fire as an important disturbance in assembling plant community in the overlooked OGG ecosystems, integrating theorical knowledge and practices applied to the conservation and restoration of OGG. (AU)