Summary

Spatial interactions among plants and between plants and animals play a key role for the dynamics of terrestrial communities. Yet, ecology largely lacks a quantitative understanding of the traits and processes governing these spatial interactions. In this project, we therefore investigate how functional traits determine plant-plant and plant-animal interactions in space, and how these spatial interactions determine long-term plant fecundity. Specifically, we study a species-rich, ecologically and economically important group of South African woody plants (genus Protea) and their key pollinators and seed predators.

As a basis for this project, we produced high-resolution maps of 28 plots à 4 ha that contain different densities and compositions of Protea species. In total, these maps represent the species identity and precise location of 217,763 shrub individuals. In the mapped communities, we conducted experiments, pollinator observations as well as measurements of plant functional traits and plant fecundity. Novel Bayesian neighbourhood analyses of these data enable the trait-based quantification of spatial interactions from the perspective of both plants and animals. In particular, we study (1) to what degree different Protea species depend on different pollinator guilds, (2) how the spatial distribution of Protea-linked resources (nectar and seeds) shapes the density and movements of pollinators and seed predators, (3) how plant traits affect plant-plant and plant-animal interactions, and (4) how these interactions determine the long-term fecundity of Protea individuals. The project thus aims to advance a trait-based understanding of species-rich communities that is necessary to forecast the dynamics of novel communities created by global change.