The aim of the VULCAN project was to investigate how climate change will affect shrubland ecosystems. Warmer, drier conditions were artificially recreated at a number of test plots spread throughout northern and southern Europe. The VULCAN consortium performed several different analyses on the test plots and adjacent control plots to identify and quantify potential impacts. Ecologists with the University of Tartu in Estonia installed equipment above the plots to measure spectral reflectance in the visible spectrum (400-950 nanometres). The data was used to calculate two key vegetation indices: the Normalized Difference Vegetation Index (NDVI) and the Photochemical Reflectance Index (PRI). NDVI, which measures the existence of healthy, green vegetation, was higher in the plots where warmer night time temperatures were induced versus the control plots. In contrast, the plots where rainfall was restricted had lower NDVI values. Due to saturation problems in regions with dense vegetation (e.g. Wales), green biomass was also measured in the field. The field data corroborated the NDVI results. Higher PRI values were also observed in the night time warming plots, signalling greater photosynthetic activity. As with NDVI, PRI values were lower for the drought plots. In fact, the Estonian ecologists discovered that PRI was, in general, well correlated with NDVI. This suggests that the photochemical efficiency of the shrubland ecosystem's vegetation increases as the temperature rises, triggering the production of additional biomass. Eliciting more definitive conclusions will require additional research, particularly to address the inherent variation in NDVI that exists between regions. Nevertheless, the University of Tartu has successfully demonstrated that reflectance measurements can provide valuable information about the effects of climate change on vegetation.
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