On a more personal note, this was the last chapter of my PhD and also my first real experiment. I learned so much from collaborating with everyone at Princeton, UCLA and Sedgwick Reserve in CA.

For more detail, check out the preprint: www.biorxiv.org/content/10.1...

Or check out @zachgold.bsky.social's upcoming ESA talk if you will be in Baltimore: events.rdmobile.com/Sessions/Det...

Overall, our results suggest that higher-order interactions can come about from the combination of spatial clustering and a competitive hierarchy. Because these two properties are prevalent in natural plant communities, higher-order interactions may be more common than previously thought.

We hypothesized that a competitive hierarchy might underlie these changes in fecundity. To test this, we came up with a metric that quantifies the difference in competitive effect for each background species. Background species that are more imbalanced produce larger higher-order interactions.

These observed higher-order interactions are correlated with changes in the traits of background competitors due to their spatial arrangement, suggesting a possible mechanistic underpinning for the shifts in interaction strength.

Differences in the fecundity of focal individuals therefore reveal the relative strength of intra to interspecific higher-order interactions.

Focal species fecundity changes as a result of the arrangement of competitors... in other words, we have found higher-order interactions!

In our experiment, we manipulated the spatial arrangement -- but not the number or identity -- of background species competing with focal individuals (see figure above). When competitors are clustered, they cannot engage in as many interspecific higher-order interactions as when they are mixed.

scholar.google.com/citations?us...