Tuesday, June 2, 2015

Diet of large herbivores in Africa

Tyler Kartzinel's (and coauthors') new paper is out on diets of African herbivores.

This has the potential to be a classic. Or at least the start of a number of classic studies.

The authors examine the diets of 7 large mammalian herbivores at Mpala in Africa. Taken over a 2 month period, it's essentially a snapshot of the diets of the animals. The authors'  main goal was to better understanding dietary niches in order to better understand the maintenance of herbivore diversity.

The authors do a great job of just quantifying the diets of the herbivores. This has never been done with so many animals in one place. Even just determining the proportion of grasses and legumes for the herbivores is interesting. Seeing how much mallow buffalo (generally considered a grazer) upends their dietary strategy.

The authors also then look essentially species by species at dietary overlap (see above). It's a fine-grained approach to understanding who eats what plants.

One of the authors' main conclusions is probably the most important for rethinking large herbivores: "dietary similarity was sometimes greater across grazing and browsing guilds than within them."

Yes, grazers and browsers can be identified, but it is much more complex than that. 

As more samples are taken over time and more sites compared, the broader web of interactions among plants and their herbivores are likely to be better understood. 

For example, how consistent are these diets over time?

Are their times of year when niche overlap (and maybe competition) is greatest?

How flexible are the diets of these animals?

Only time will tell....

Kartzinel, T. R., P. A. Chen, T. C. Coverdale, D. L. Erickson, W. J. Kress, M. L. Kuzmina, D. I. Rubenstein, W. Wang, and R. M. Pringle. 2015. DNA metabarcoding illuminates dietary niche partitioning by African large herbivores. Proceedings of the National Academy of Sciences:201503283.