Metabolic fingerprinting for bio-indication of nitrogen responses in Calluna vulgaris heath communities

Increased atmospheric deposition of nitrogen (N) over the last 50 years is known to have led to deleterious effects on the health of Calluna vulgaris heathland, with increased proliferation of grasses and loss of species diversity. However, currently it is difficult to attribute damage specifically to N deposition rather than other drivers of change such as inappropriate management. Metabolic fingerprinting using FT-IR offers a rapid, cost-effective and “holistic” means for quantifying foliar biochemistry responses specifically to N deposition. To test the potential of this approach we used a long term lowland heath N addition study in Chesire, England. FT-IR spectra of treated C. vulgaris shoot material showed that responses were detectable above 20 kg N ha−1 year−1. Differentiation was also evident in C. vulgaris metabolic fingerprints due to additional watering. We have shown that FT-IR is able to identify biochemical variations in C. vulgaris related to increases in received N and water. This technique therefore provides a sensitive measure of biochemical change in response to N addition, and allows development towards predictive modelling of N deposition at the landscape level.