Understanding the processes that determine the composition of co-occurring species, and why some species are rare while others are common have been central aims in community ecology for decades. While the importance of the abiotic environment for plant community assembly and rarity has been studied intensively, much less is known about the importance of biotic interactions, including competition and plant enemies such as herbivores or pathogens.
In my talk, I will present evidence that biotic interactions are important for plant establishment, and will dig into the mechanisms of how invertebrate herbivores affect the structure of plant communities. I will further discuss whether biotic interactions can drive plant rarity at large spatial scales and will show that particularly soil pathogens and plant competition may well contribute to large scale rarity. Finally, I will focus on variation in the strength of biotic interactions along environmental gradients, and will highlight the importance of including context-dependency in studies of biotic interactions.