Estuarine tidal flats have been reclaimed in many countries for various purposes such as agricultural and industrial development. Along with concerns about negative environmental impacts, new challenges of how to manage the novel land ecosystems have also arisen. This study investigates the succession of soil microbial communities in coastal reclaimed lands, which may provide guidance for subsequent restoration or conservation plans. Community assembly may be driven by deterministic, stochastic, or a combination of both process. However, it is hypothesized that coastal reclaimed soil ecosystems subjected to high selection pressure such as salt stress would behave deterministically. To test this hypothesis, three types of mesocosms with different soil inoculants were installed in coastal reclaimed land. Ten soil characteristics and microbial species abundance were monitored for two years using physiochemical and metagenomic analysis respectively. Data were then assessed by ordination analysis to infer the ecological succession.
Results/Conclusions
Although there were minor seasonal changes, the mesocosms generally retained their distinct physiochemical conditions. Change in individual mesocosms over time revealed no significant differences, whereas there were significant differences between mesocosms. Despite these differences, there was a convergent pattern in microbial community assembly. Ordination analysis showed that differences in community assemblies decreased and shifted in the same direction. Changes in diversity also showed the same pattern. In particular, bacterial communities had a stronger pattern of convergence than fungal communities. Lastly, the fact that physiochemical properties were not significantly correlated with this pattern implies that the microbial communities were more strongly influenced by macroenvironmental changes in coastal ecosystem rather than soil properties.