Responses of dry meadow Kobresia myosuroides and Carex rupestris to Nitrogen fertilization for East of Tvan, 2013 - 2015

A common response of plant communities to increased nitrogen (N)
deposition is a shift in species’ abundances. Multiple factors have
been proposed to explain the changes in abundance, notably competition
and soil acidification. We hypothesized that a plant species that
decreased in abundance with elevated N would have lower
ectomycorrhizal fungi, altered root-associated bacteria communities,
and/or greater susceptibility to Al toxicity than a species that
increased in abundance with increasing N deposition. We examined
changes in plant–microbe associations and Al toxicity in two dominant
species from an alpine dry meadow community subjected to long-term
low-level N addition. Carex rupestris has increased in cover over time
with N addition and Kobresia myosuroides has decreased. We conducted
field sampling of soil microbes from treatment plots and tested
whether field levels of Al have toxic effects on sedge species in a
greenhouse study. Declines in ectomycorrhizal infection of Cenococcum
geophilum occurred on Kobresia with increasing N treatment. In
contrast, neither Al level nor changes in bacteria community
composition corresponded with the change in cover of sedge species.
Decreased ectomycorrhizal infection may have contributed to the
decrease in abundance of Kobresia. This study contributes to an
understanding of the types of plant–soil interactions that may
influence how plant species respond to N deposition and rejects Al
toxicity and changes in bacteria composition as factors that likely
play a role in changes in sedge abundance. Citations: Potter, T. S., Owens, W. M., Bowman, W. D. (2019). Do plant–microbe
interactions and aluminum tolerance influence alpine sedge species’
responses to nitrogen deposition?. Ecosphere, 10(7), e02775.