PhD ceremony Mr. A.L.D. van der Plas: Understanding trait-based community assembly in tropical savannahs at different tropic levels

PhD ceremony: Mr. A.L.D. van der Plas

Dissertation: Understanding trait-based community assembly in tropical savannahs at different tropic levels

Promotor(s): prof. H. Olff

Faculty: Mathematics and Natural Sciences

Fons van der Plas has studied in African savannahs to which extent trophic interactions are important in shaping communities of plants and insects en how different processes act simultaneously on community assembly. One of the most important questions in ecology is which processes form ecological communities: communities of locally co-occurring plant or animal species. More insight in this would improve the protection of rare species.

Although research has led to many new insights, we can still hardly predict which species do or do not occur in a certain nature area. There are two possible reasons for this. Firstly, food relations between species are usually ignored in research, even though it would make intuitive sense is these could explain why a species is or is not present in a certain area. Secondly, research often focuses on the study of one ecological process in isolation, such as the importance of competition in community assembly. In reality multiple processes, such as competition ánd predation, act simultaneously in shaping communities.

It appeared that one cannot understand the assembly of grasshopper communities without also taking grass (food) and ungulate (competitors) communities into account. Furthermore, it was found that despite the fact that deterministic processes do shape ecological communities to some extent, community assembly is mostly stochastic. We therefore have to accept that community assembly is highly unpredictable.