TY - JOUR

T1 - Nitrogen deposition and drought events have non-additive effects on plant growth – Evidence from greenhouse experiments

AU - Meyer-Grünefeldt, Maren

AU - Friedrich, Uta

AU - Klotz, Miriam

AU - Oheimb, Goddert

AU - Härdtle, Werner

PY - 2015/3/4

Y1 - 2015/3/4

N2 - Climate change and nitrogen deposition affect biodiversity and ecosystem functioning, but interactive effects of these global change drivers are poorly understood. We analysed single and interactive effects of nitrogen (N) fertilisation and drought on the growth performance of Calluna vulgaris. We measured biomass production and allocation, tissue nutrient (N, phosphorus (P) and carbon (C)) concentrations, N allocation patterns (using 15N tracer) and plant's water status (using δ 13C signatures) as response variables in a 2-year greenhouse experiment. N fertilisation increased biomass production and biomass shoot:root ratios. 15N allocation patterns indicated an increasing aboveground N allocation following N fertilisation. Tissue δ 13C signatures were higher in N-fertilised plants. Plant responses to drought were weak. We found strong antagonistic interaction effects of N fertilisation and drought for biomass production. δ 13C values peaked when N-fertilised plants were subjected to drought, indicating that N fertilisation increased the evaporative demands of Calluna plants, likely due to increased biomass shoot:root ratios, which in turn resulted in higher drought susceptibility. As an important consequence, even slight drought events may weaken the competitiveness of Calluna when interacting with enhanced airborne N loads. Single-factor studies, thus, need to be complemented by multi-factor analyses to assess conceivable impacts of co-occurring global change drivers.

AB - Climate change and nitrogen deposition affect biodiversity and ecosystem functioning, but interactive effects of these global change drivers are poorly understood. We analysed single and interactive effects of nitrogen (N) fertilisation and drought on the growth performance of Calluna vulgaris. We measured biomass production and allocation, tissue nutrient (N, phosphorus (P) and carbon (C)) concentrations, N allocation patterns (using 15N tracer) and plant's water status (using δ 13C signatures) as response variables in a 2-year greenhouse experiment. N fertilisation increased biomass production and biomass shoot:root ratios. 15N allocation patterns indicated an increasing aboveground N allocation following N fertilisation. Tissue δ 13C signatures were higher in N-fertilised plants. Plant responses to drought were weak. We found strong antagonistic interaction effects of N fertilisation and drought for biomass production. δ 13C values peaked when N-fertilised plants were subjected to drought, indicating that N fertilisation increased the evaporative demands of Calluna plants, likely due to increased biomass shoot:root ratios, which in turn resulted in higher drought susceptibility. As an important consequence, even slight drought events may weaken the competitiveness of Calluna when interacting with enhanced airborne N loads. Single-factor studies, thus, need to be complemented by multi-factor analyses to assess conceivable impacts of co-occurring global change drivers.

KW - Biology

KW - Ecosystems Research

KW - biomass allocation

KW - Calluna vulgaris

KW - climate change

KW - interaction effects

UR - http://www.scopus.com/inward/record.url?scp=84923430610&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/9c954db2-6255-3374-8865-74b7f93668da/

U2 - 10.1080/11263504.2013.853699

DO - 10.1080/11263504.2013.853699

M3 - Journal articles

AN - SCOPUS:84923430610

VL - 149

SP - 424

EP - 432

JO - Plant Biosystems

JF - Plant Biosystems

SN - 1126-3504

IS - 2

ER -