Bench to benthos - predicting ecological community assembly using seagrass restoration

Understanding how species re-colonise an area they have previously been lost from, to assemble new ecological communities after conservation methods are used to restore these habitats, is vital to ensure our limited resources are used as effectively as possible, maximising the benefits we get from natural ecosystems. For example, seagrass meadows provide coastal stabilisation, biodiversity enhancement, nutrient cycling, and are a global source of blue carbon capture, yet have been substantially lost from around the UK coast due to disease, pollution, and coastal development. We are pioneering UK and global efforts to successfully restore resilient seagrass meadows to ensure that future generations will benefit from the crucial ecosystem services they provide.

Previous work studying ecological community assembly has identified four main processes that affect the final outcome: (i) how well each species' biology fits with the local habitat (niche selection); (ii) how easily individuals can move from one place to another (dispersal); (iii) how important random events are in promoting or reducing success (ecological drift); and (iv) how quickly variation in species genones can accumulate in a way that benefits them (genetic diversification). This work has generally been carried out using simplified laboratory experiments with micro-organisms like bacteria, or with mathematical equations and computers, to predict how patterns of re-colonisation develop over time. Other approaches have relied on inferring the historical mechanisms involved with community assembly by using current snapshots of the community, which can be strongly influenced by factors beyond our control. While these approaches are important first steps in building our understanding of the importance of different ecological assembly processes, we lack data and evidence from more complex, natural ecosystems at the start of their re-assembly journey to properly test the real-world application of advances in theory This increased natural complexity may introduce surprising or unexpected new features that previous work was unable to account for or predict.

Our project will combine insights from previous laboratory- and mathematical-based approaches, with field data of the micro-organisms that live on the seagrass roots and leaves, from recently restored UK seagrass meadows (1 to 5 years old). We will develop and test novel predictions about the relative importance of the four assembly processes defined above, during the early phases of seagrass restoration. Importantly, we will also build a global network of researchers to provide further expertise and data from later stages of seagrass restoration. We predict that niche selection and ecological drift will be most important for determining the longer-term success, resilience and stability of these vital but threatened ecosystems, given the physical and temporal limitations of this system. Our work will be the first to directly assess the mechanisms that drive early community assembly in this globally important ecosystem.