Who eats what?

Sankey diagram showing the relative abundance of reads per plant family in the total dataset (left) and per herbivore species (right). Note that the values have been adjusted to relative frequencies per herbivore.

CASE: One of my PhD thesis projects on the use of environmental DNA metabarcoding of faeces from wild and domestic herbivores to find out how the food resources in the wildlife reserve they inhabit are shared. In short, the question was what were these herbivores eating, and how do their diets overlap?

PROBLEM: I obtained a big dataset with the many different plants found in numerous faeces samples. This needed to be summarized into one cohesive scientific poster as well as in comprehensive but clean figures for a scientific publication.

SOLUTION: I created a simple and easy to understand Sankey diagram showing the ‘resource flow’: with the overall relative proportion of the plant groups in the dataset on the right side, and their relative contribution to the diets of the herbivore species to the right. For deeper insight into the dietary overlap, I decided on using an Upset-plot, which provides an uncluttered alternative to showing numerous Venn-diagrams for each possible herbivore species combination.

RESULT: A successful poster presentation and a published scientific paper, available at: doi.org/10.1002/edn3.168

This is the resulting scientific poster. I added a QR code to my poster to entice visitors to go to my website for the interactive version of the Sankey-diagram I had made available for the session, and to contact me for further questions or discussion.

I made some fun stickers to hand out during the poster session, also including the URL to my website.

For the scientific publication, I used the main figure of the poster and adjusted it to show a scale from primarily grass (Poaceae) eating herbivores to those eating primarily legumes (Fabaceae). I also included the scientific names of the herbivores.

Up-set plots are not widely used, but they provide a wealth of information if you know how to read them. I provided a graphical example of this using a standard Venn-diagram and indicating the bars that make up the intersections (the surface areas) of this Venn-diagram using capital letters.

For the captions of these figures and further details on this study I refer you to the open access published article: doi.org/10.1002/edn3.168