The use of Leaf Characteristics of Common Oak (Quercus Robur L.) to Monitor Ambient Ammonia Concentrations

摘要

Biomonitoring of atmospheric ammonia (NH_3) concentrations is generally performed with epiphytic lichens, using species' abundances and/or nitrogen concentration as monitoring tools. However, the potential of leaf characteristics of trees to monitor the atmospheric NH_3 concentration has remained largely unexplored. Therefore, we performed a passive biomonitoring study with common oak {Quercus robur L.) at 34 sampling locations in the near vicinity of livestock farms, located in Flanders (northern Belgium). We aimed at evaluating the potential of specific leaf area, leaf area fluctuating asymmetry, stomatal resistance, and chlorophyll content of common oak to monitor a broad range of NH_3 concentrations (four-monthly average of 1.9-29.9 μgm~(-3)). No significant effects of ambient NH_3 concentration on the abovementioned leaf characteristics were revealed. Probably, differences in climate, soil characteristics, and concentrations of other air pollutants and/ or genotypes confounded the influence of NH_3. Consequently, this study demonstrates the inability of using these morphological, anatomical, and physiological common oak leaf characteristics to monitor ambient NH_3 concentration.