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Slow recovery of H igh A rctic heath communities from nitrogen enrichment
Author(s) -
Street Lorna E.,
Burns Nancy R.,
Woodin Sarah J.
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13265
Subject(s) - tundra , ecosystem , nutrient , moss , ecology , phosphorus , arctic , limiting , abundance (ecology) , chemistry , biology , zoology , environmental science , organic chemistry , mechanical engineering , engineering
Summary Arctic ecosystems are strongly nutrient limited and exhibit dramatic responses to nitrogen ( N ) enrichment, the reversibility of which is unknown. This study uniquely assesses the potential for tundra heath to recover from N deposition and the influence of phosphorus ( P ) availability on recovery. We revisited an experiment in S valbard, established in 1991, in which N was applied at rates representing atmospheric N deposition in E urope (10 and 50 kg N ha −1 yr −1 ; ‘low’ and ‘high’, respectively) for 3–8 yr. We investigated whether significant effects on vegetation composition and ecosystem nutrient status persisted up to 18 yr post‐treatment. Although the tundra heath is no longer N saturated, N treatment effects persist and are strongly P ‐dependent. Vegetation was more resilient to N where no P was added, although shrub cover is still reduced in low‐ N plots. Where P was also added (5 kg P ha −1 yr −1 ), there are still effects of low N on community composition and nutrient dynamics. High N, with and without P , has many lasting impacts. Importantly, N + P has caused dramatically increased moss abundance, which influences nutrient dynamics. Our key finding is that A rctic ecosystems are slow to recover from even small N inputs, particularly where P is not limiting.