Assessing the effect of increased droughts on forest communities

11 July 2019

Global forest die-off, due to extreme drought and heat waves, has been observed across all vegetated continents. Drought-induced collapse of dominant tree species can change the community structure of forests, alter ecosystem biodiversity and feedbacks between the biosphere and climate. 

Understanding drought sensitivities of co-occurring dominant tree species in forest ecosystems is critical for predicting drought consequences on forest functioning. 

In this study, Plant & Food Research scientist, Dr Shuang-Xi Zhou, in collaboration with scientists in China and Australia, studied drought sensitivity and post-drought resilience among ecologically important, co-occurring tree species in sub-tropical southern China, a region that has experienced significant mortality in tree species over past decades. These forests have relatively high carbon uptake

and represent large carbon sinks, making change significant for local and/or global carbon balance, biogeochemical cycles and biodiversity. 

The study analysed three tree species with contrasting drought sensitivities (Syzygium rehderianum > Castanopsis chinensis > Schima superba) and employed two different watering regime treatments towards mortality – a higher intensity, short duration (fast drought) method and a lower intensity, lower duration (slow drought) method. Physiological recovery was assessed with re-watering. The study found that the most drought-resistant species (Schima superba) can maintain water transport at a greater degree of water stress, facilitating favorable plant water status for a longer time compared to the other two species. 

This is one of the first studies to provide ecophysiological information on species-specific drought response strategies and these findings contribute to understanding of how species would diverge in drought responses and post-drought recovery. 


Journal reference: 

Duan H, Li Y, Xu Y, Zhou S, Liu J, Tissue DT, Liu J 2019. Contrasting drought sensitivity and post-drought resilience among three co-occurring tree species in subtropical China Agricultural and Forest Meteorology 272-3 Doi: 10.1016/j.agrforme

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