Erika Buscardo
University of Campinas
Erika Buscardo is a visiting researcher in the Department of Animal Biology, at the University of Campinas. She holds a degree in biology and a Ph.D. in ecology. The main area of Erika’s research is soil microbe – plant interactions, with particular interest in the structure and functioning of microbial communities and their implications for ecosystem biogeochemistry. She is interested in separating underlying natural spatio-temporal dynamics from ecosystem responses to natural disturbances (e.g., fire, zoogeochemistry) and global change drivers (climate and land use change, atmospheric nitrogen deposition). She has worked in Mediterranean, temperate and tropical ecosystems and she is involved in long-term ecological research projects in South America.
Abstract:
Nitrogen cycle in a native tropical montane forest vs. an exotic pine plantation
ARIADNA MATILDE QUINTERO MUÑOZ, ERIKA BUSCARDO , LASZLO NAGY
Department of Animal Biology, University of Campinas, Campinas, São Paulo, Brazil
Soil microbiota has an important ecological role in nutrient cycling. We quantified how substitution of Araucaria angustifolia , an endemic conifer, by Pinus taeda plantation altered the N cycle in a Neotropical montane forest. Microbial biomass (C, N) and genes associated with N cycle were quantified twice a year to capture seasonal differences. There were significant differences in microbial biomass and gene composition between bacteria and archaea with season and conifer species. Araucaria had significantly higher microbial biomass than pine and this was more accentuated in the organic layer than in the mineral topsoil. The patterns were consistent across seasons. The highest abundance of nifH was found in the pine mineral layer, in correspondence with the lowest [NH4+]. The amoA gene abundances of ammonium-oxidizing archaea and ammonium-oxidizing bacteria were negatively correlated with [NH4+]. The plantation showed higher abundance of bacteria and archaea amoA genes when compared to the araucaria forest. In the plantation, the nifH and archaea amoA genes were found in greater abundances in the mineral soil than in the organic layer. The results show how an exotic and invasive species can affect biogeochemical cycling with potential cascade consequences on ecosystem functions and services.