Tracking food choice via feces – novel applications of FTIR

Studies on the foraging ecology of wildlife species are of fundamental interest because animal foraging is closely related to ecological issues such as resource distribution and population dynamics. Wildlife species in alpine ecosystems are potentially threatened by ongoing climate change, which is likely to reduce the availability and digestibility of many plants. Since certain plant parts and their quality can significantly influence herbivore population dynamics, there is a need for methods that can assess both the composition and quality of food at different spatial and temporal scales. Fourier transform infrared spectroscopy (FTIR) is a well-established analytical technique to determine chemical and physio-chemical properties of a wide range of biomaterials. This method allows the determination of specific plant parts or phytochemical compositions. We use samples of crops, gizzards and fecal droppings from individual wild black grouse to validate spectral correlations of undigested, mechanically digested and fully digested plant material that represents natural variation in the foraging ecology of grouse species. In addition, we conduct feeding experiments with captive birds and fecal analyses to validate the spectral correlations between undigested and digested plant material. To understand spatio-temporal dynamics of potential feeding plants of herbivore species, we need comprehensive spectral correlation of food plants, plants parts and feces. Our project will create a comprehensive reference database of species-specific spectral signals. Comparative FTIR analyzes of fresh plant samples and feces provide an in vivo window on digestive processes and offer new insights into phenological and annual shifts in plant communities.