학술논문
Plant and soil nitrogen in oligotrophic boreal forest habitats with varying moss depths: does exclusion of large grazers matter?
Ecosystem Ecology-Original Research
Ecosystem Ecology-Original Research
Document Type
Academic Journal
Source
Oecologia. July 2021, Vol. 196 Issue 3, p839, 11 p.
Subject
Language
English
ISSN
0029-8549
Abstract
Author(s): Maria Väisänen [sup.1] [sup.2], Maria Tuomi [sup.3], Hannah Bailey [sup.1], Jeffrey M. Welker [sup.1] [sup.4] [sup.5] Author Affiliations: (1) grid.10858.34, 0000 0001 0941 4873, Ecology and Genetics Research Unit, [...]
The boreal forest consists of drier sunlit and moister-shaded habitats with varying moss abundance. Mosses control vascular plant-soil interactions, yet they all can also be altered by grazers. We determined how 2 decades of reindeer (Rangifer tarandus) exclusion affect feather moss (Pleurozium schreberi) depth, and the accompanying soil N dynamics (total and dissolvable inorganic N, [delta].sup.15N), plant foliar N, and stable isotopes ([delta].sup.15N, [delta].sup.13C) in two contrasting habitats of an oligotrophic Scots pine forest. The study species were pine seedling (Pinus sylvestris L.), bilberry (Vaccinium myrtillus L.), lingonberry (V. vitis-idaea L.), and feather moss. Moss carpet was deeper in shaded than sunlit habitats and increased with grazer exclusion. Humus N content increased in the shade as did humus [delta].sup.15N, which also increased due to exclusion in the sunlit habitats. Exclusion increased inorganic N concentration in the mineral soil. These soil responses were correlated with moss depth. Foliar chemistry varied due to habitat depending on species identity. Pine seedlings showed higher foliar N content and lower foliar [delta].sup.15N in the shaded than in the sunlit habitats, while bilberry had both higher foliar N and [delta].sup.15N in the shade. Thus, foliar [delta].sup.15N values of co-existing species diverged in the shade indicating enhanced N partitioning. We conclude that despite strong grazing-induced shifts in mosses and subtler shifts in soil N, the N dynamics of vascular vegetation remain unchanged. These indicate that plant-soil interactions are resistant to shifts in grazing intensity, a pattern that appears to be common across boreal oligotrophic forests.
The boreal forest consists of drier sunlit and moister-shaded habitats with varying moss abundance. Mosses control vascular plant-soil interactions, yet they all can also be altered by grazers. We determined how 2 decades of reindeer (Rangifer tarandus) exclusion affect feather moss (Pleurozium schreberi) depth, and the accompanying soil N dynamics (total and dissolvable inorganic N, [delta].sup.15N), plant foliar N, and stable isotopes ([delta].sup.15N, [delta].sup.13C) in two contrasting habitats of an oligotrophic Scots pine forest. The study species were pine seedling (Pinus sylvestris L.), bilberry (Vaccinium myrtillus L.), lingonberry (V. vitis-idaea L.), and feather moss. Moss carpet was deeper in shaded than sunlit habitats and increased with grazer exclusion. Humus N content increased in the shade as did humus [delta].sup.15N, which also increased due to exclusion in the sunlit habitats. Exclusion increased inorganic N concentration in the mineral soil. These soil responses were correlated with moss depth. Foliar chemistry varied due to habitat depending on species identity. Pine seedlings showed higher foliar N content and lower foliar [delta].sup.15N in the shaded than in the sunlit habitats, while bilberry had both higher foliar N and [delta].sup.15N in the shade. Thus, foliar [delta].sup.15N values of co-existing species diverged in the shade indicating enhanced N partitioning. We conclude that despite strong grazing-induced shifts in mosses and subtler shifts in soil N, the N dynamics of vascular vegetation remain unchanged. These indicate that plant-soil interactions are resistant to shifts in grazing intensity, a pattern that appears to be common across boreal oligotrophic forests.