Restoring for a resilient future: Woodland community assembly trajectories in the face of multiple stressors

Ecosystem restoration is proposed internationally as a nature-based climate solution. The UK aims to plant 50,000 ha trees per year by 2035. This planting has multiple aims: addressing biodiversity loss, increasing carbon storage and reaching Net Zero, and bolstering associated ecosystem service co-benefits. The

direction that restoration trajectories take towards these aims depends upon multiple stressors, including drought and land degradation legacies, for instance dominant vegetation that can arrest woodland succession. However, an important stressor - surface-level ozone - remains overlooked. This is despite

evidence of ozone-induced declines in net primary productivity of near 50%. This suggests that the presence of ozone could seriously compromise multiple restoration goals, particularly Net Zero. We know, for individual trees, that ozone can impair stomatal control and reduce root-to-shoot ratios. This

makes ozone-affected plants more susceptible to stressors such as drought, and alters water and nutrientuptake relationships. However, we have very limited knowledge of how ozone, when combined with other stressors, influences community assembly restoration trajectories. We hypothesize that initial restoration

trajectories in the context of multiple stressors will depend on the functional traits of species involved. This is because environmental filters (i.e. different stressors) can act on the distribution of functional traits. At the same time, stress can alter epigenetics and gene expression with consequences for plant function.

This PhD, using experiments and cutting-edge analytical techniques, asks: Does ozone create greater divergence in initial woodland community restoration trajectories in the presence of additional stressors (drought, co-occurring weed species)? Can relationships among functional traits, ecophysiology and epigenetic mechanisms explain

divergent restoration trajectories? Ultimately, answering these fundamental science questions will help inform tree-planting interventions and modelling initiatives to ensure resilient restoration trajectories beyond the UN Decade of Ecosystem Restoration.