Active versus passive forest rewilding: impacts on soil microbial and fungal communities and carbon storage in Hong Kong secondary forests

Team: Coşkun Güçlü, Billy Hau, Stephan Gale, Matthew Seymour, Cheuk Mang Lung, Louise Amy Ashton

 
Reforestation is integral to meeting global conservation and environmental targets, with numerous international consortia seeking the restoration of millions of hectares by the mid-century. However, the most effective pathways for re-establishing biodiverse, self-sustaining forests which can deliver ecosystem services remain debated both in temperate and tropical systems. Additionally, while plant and faunal communities tend to receive greater emphasis in restoration, the responses of key ecosystem engineers, such as soil microbial and fungal species, remains understudied in the context of conservation ecology.

Establishing the roles that passive versus active ‘rewilding’ restoration approaches may play in tropical systems requires further investigation. Our work aims to understand how active and passive forms of reforestation may lead to differential outcomes for community structure and ecosystem function. Specifically, we use environmental DNA metabarcoding to characterize the community structure and diversity of soil microbial and fungal species, which are known to play a key role in the long term storage of carbon in forest soils. In addition to this, we are measuring soil carbon respiration in order to capture the carbon balance of forest soils in different treatment types. The work is being conducted at the Kadoorie Farm and Botanic Gardens (KFBG)in the New Territories of Hong Kong. The KFBG team have restored a 9 hectare site of forest with tree species known to have grown in the primordial forests of Hong Kong prior to the mass deforestations the region experienced in the 20thcentury. This site comprises the actively restored treatment, which is being compared to 40-50 year old secondary forests, as well as open scrublands in adjacent regions to KFBG. The project will deliver essential findings for evaluation of active and passive forms of restoration, and findings will be submitted to the Botanic Gardens Conservation International organisation for compilation into a global review on rewilding. We also hope to use our findings to make policy recommendations for government and conservation practitioners both locally and internationally.

Funded by the Croucher Foundation

You can read and interview about the project with Coşkun Güçlü here.