Despite the importance of herbivory for ecosystem functioning, the direct assessment of plant-herbivore interactions is still not part of current monitoring efforts. Our preliminary analysis of Svalbard reindeer diet revealed considerable discrepancy in the estimated proportion of ingested plant species using micro-histology of plant fragments, compared to modern DNA metabarcoding and stable isotopes methods, thus calling for the rigorous assessment of these three methods.
The PIECEMEAL project, led by Stefaniya Kamenova at the Norwegian University of Life Sciences (NMBU) was funded by the Svalbard Science Forum, and brought together six international experts from Norway, France, Spain, Finland, USA and Sweden in each of the three diagnostic techniques, with colleagues in both the Norwegian Polar Institute in Ny-Ålesund and UNIS in Longyearbyen. Taking advantage of a rare opportunity of working on the same physical samples, they were able to provide a cost-efficient and ultimately non-invasive way, to reliably characterise Svalbard reindeer diet. These data allow better mechanistic models of both reindeer population growth, Svalbard plant community dynamics, and tundra ecosystem processes, as the climate continues to warm. Finally, by comparing three key methods for identifying the plant ingested by reindeer, our combined network and workshop project led to the establishment of a “gold standard” toolbox for diet analysis, relevant not only to Svalbard reindeer, but also to large herbivores in general.
