Stoichiometric response of shrubs and mosses to long-term nutrient (N, P and K) addition in an ombrotrophic peatland
Wang, M., T. Larmola, M. T. Murphy, T. R. Moore and J. L. Bubier. 2015. Springer International Publishing
Abstract
Background: and aim Although ombrotrophic peatlands
are nutrient deficient, it is not clear to what extent plants
will respond to changes in nutrient availability.
Methods: We examined the changes in foliar stoichiometry
and species abundance of four shrub species and
moss after a decade of nitrogen (N), phosphorus (P) and
potassium (K) fertilization at the Mer Bleue bog, eastern
Canada.
Results: Shrub abundance increased and moss cover
decreased after fertilization with 6.4, 5 and 6.3 g m-2
yr-1 of N, P and K, respectively; foliar concentrations of
N, P, K and calcium (Ca) and magnesium (Mg) were
affected. Stoichiometry showed mainly N limitation
after P and K fertilization and P (co)limitation after high
levels of N addition in shrubs; moss showed consistent
K or KN-co-limitation, even with PK and NPK additions.
Shrubs exhibited the strongest homeostasis (the
maintenance of an organism's tissue chemical composition with
changes in environmental resources) to N, with
the homeostatic regulation coefficient (H)>9.7, compared
to 1.4 in moss. For P and K, shrubs showed
weaker homeostasis than N, while moss had a stronger
homeostasis.
Conclusions The strong homeostasis of shrubs may be
an adaptive strategy to limited availability of soil N and
P.
Key Words
Stoichiometry, Homeostasis, Chamaedaphne calyculata, Sphagnum moss, Kalmia angustifolia, Rhododendron groenlandicum, Vaccinium myrtilloides
