Using plant cuticular alkanes to study plant-animal interactions on pastures

Abstract

Two experiments were conducted to validate an approach of using plant cuticular alkanes to estimate diet composition and fecal output. In the first experiment, n-alkane patterns of the four major pasture species were determined and compared and a further two sets of pasture mixtures were prepared to validate the use of plant n-alkane patterns to estimate species composition. In the second experiment, estimates of daily fecal output of grazing sheep were compared using controlled-released devices containing either Cr2O3 or alkanes. There were considerable differences in odd-numbered alkanes and in their total content between species. Results from the first experiment, where two sets of pasture mixtures were analyzed suggest that it is feasible to separate species composition using differences in n-alkane pattern. The second experiment showed that accurate estimation of daily fecal output can also be obtained using capsules containing alkanes. Key words: n-alkane, pasture, diet composition, fecal output