The succession in sessile communities is generally gradual, continuous and deterministic, and there is a great influence of founder on subsequent successional stages. In open systems, any colonizer can potentially found a community, as in a lottery guided by stochasticity. If the founder organism has an advantage window during the early colonization, its influence in the community can be maximized, representing a priority effect. These effects can inhibit or facilitate the occurrence of new organisms, affecting community structure e also ecosystems processes. In recent decades, anthropogenic action is leading to biodiversity loss in several systems, mainly in coastal areas, altering colonization scenarios with substantial impacts on community stability, resistance and resilience, even against the introduction of non-indigenous species. Using an experimental approach in which the characteristics of early colonizers were manipulated, I tested how the founders¿ identity, taxonomic diversity and functional diversity affect the structure of subtidal sessile communities in a subtropical area. Overall, the three manipulations had shown that the founder identity is the most important component of colonization, affecting either richness or community structure along succession. When the founders were a persistent group in the community, monopolizing space and being resistant to predation, community diversity in later successional stages was low. Surprisingly, both initial taxonomic and functional diversity did not affect the occurrence of non-indigenous species and only taxonomic diversity had a little impact in the structure of the whole sessile community. Predators affected community structure, leading to a decrease of total and non-indigenous species, specially reducing the abundance of ascidians. However, predation effects were modulated by the taxonomic group of early colonizers, being evident only when founders were bryozoans. In conclusion, the founder identity matters, affecting community diversity and structure, and also modulating the effects of other processes as predation (AU) |
