Pathogen-induced tree mortality modifies key components of the C and N cycles with no changes on microbial functional diversity
Here we assessed the effects of Quercus suber dieback, caused by the exotic root pathogen Phytophthora cinnamomi, on the soil microbial community and key components of the C and N cycle. We used a spatially-explicit neighbourhood approach to analyse the effects of Q. suber trees with different health status and non-declining coexistent species on soil variables. The study was replicated in the two main Q. suber forest types of the region (closed forests and open woodlands) with contrasting soil texture characteristics. Pathogen-induced tree dieback did not affect microbial functional diversity or biomass, but translated into lower soil microbial respiration. Tree mortality induced changes in several variables of the C and N cycle, but the sign and magnitude of these effects varied depending on the local characteristics of soil texture. Coexistent species differed strongly from Q. suber in their effects on the C and N cycle. Overall, our results show that tree dieback due to invasive pathogens translates into complex short- and long-term effects on different components of the C and N cycles, despite no effects on microbial functional diversity and biomass. There are two spreadsheets with data. The spreadsheet "soil dataset" contains raw soil data. The spreadsheet "tree dataset" contains the information about neighbour trees (species, position, size and defoliation index). After each data spreadsheet, there is a spreadsheet with the associated metadata, where a description of all the variables and units can be found.