CANCELLED - Seed banks in metacommunities: when and how do they maintain biodiversity?

Background/Question/Methods

The maintenance of biodiversity depends on the availability of favorable environments, the type and strength of species interactions, and on rates of dispersal. Decades of work have revealed the importance of dispersal for metacommunity diversity while overlooking the role of temporal mechanisms for biodiversity maintenance. A widespread adaptation to temporal variability is the production of dormant seed banks, which can maintain local diversity and influence metacommunity dynamics through interactions with dispersal. We developed a discrete time, spatially explicit, stochastic metacommunity model with local dynamics governed by a classic model of seed banking annual plants. We simulated the model across a range of germination rates, seed survival rates, dispersal rates, and competition scenarios (when intra- and interspecific competition are equal or when intraspecific competition is stronger than interspecific, a locally stabilizing condition). We then conducted a sensitivity analysis to quantify the contributions of these processes and their interactions to diversity at different spatial scales.

Results/Conclusions

Compared to metacommunity dynamics without dormancy, the presence of seed banks strongly modified the traditional relationships between dispersal and diversity. In the absence of locally stable competitive interactions (inter = intra), seed banks maintained up to fourfold higher local diversity when seed survival was high, particularly at higher dispersal rates, a divergence from the classically observed relationship. When competitive interactions were locally stabilizing (intra > inter), seed banks were more important for maintaining spatial variation in community composition, especially when dispersal and survival rates were low. Consequently, seed banks maintained regional diversity across a broader range of dispersal rates than in metacommunities without dormancy. The sensitivity analysis showed that dormancy can have quantitatively similar effects on multi-scale biodiversity to dispersal, demonstrating its relevance for understanding metacommunity dynamics. It also unveiled interactive effects between dispersal and seed bank dynamics that emphasize the importance of spatial processes for understanding the local scale effects of temporal fluctuations on ecological communities. More generally, our work sheds light on when and where seed banks and dispersal jointly affect metacommunity diversity, which has important implications for curbing the spread of invasive species and promoting successful ecological restorations.