Wildebeest Diet and Movement

 

 

The Serengeti has the largest ungulate migration on Earth, but is under threat from the encroaching human population. Tail hair samples from these animals can tell us a lot about the migration cycle of these animals and how their diet changes over the year. Tail hairs can be sampled non-destructively and are made up of keratin, which is inert once formed and grows continuously until it is moulted or wears out at the end. By analysing different stable isotope ratios we can glean information on where the animal is (Sulfur isotopes and hydrogen isotopes), the type of plant diet the animal feeds on at any one time (Carbon isotopes), and whether the animal is under nutritional stress (Nitrogen isotopes).

This is a collaboration with Grant Hopcraft at MVLS, University of Glasgow. Isotope measurements for both projects below were funded by the NEIF.

Stressed out wildebeest

Masters student Isty Rysava tested whether sequential nitrogen isotope ratio (δ15N) measurements of wildebeest tail hairs could be used to measure nutritional stress along the migratory cycle.  

wilderbeest%20starvation_edited.jpg

Rapid Communications in Mass Spectrometry, Volume: 30, Issue: 13, Pages: 1461-1468, First published: 09 June 2016, DOI: (10.1002/rcm.7572)

The mean δ15N value of starved animals was greater than that of non‐starved animals, suggesting that higher δ15N values correlate with periods of nutritional stress.

The full details of this research can be found in Rysava et al. (2016).

Sulfur isoscapes

PhD student Zabibu Kabalika has analysed sulfur isotope ratios (δ34S) in grass samples throughout the Serengeti. She has plotted these on a map - an isoscape - which can then be compared to δ34S in ungulates to see if movement can be detected in cattle, and whether migrating wildebeest can be tracked using this method.

Preliminary results can be found in Kabalika et al. (2020).

d34Sgrass-isoscape.jpg