Located at 22.3°N, Hong Kong lies within the subtropics and its biodiversity is surprisingly high. Various habitats can be found, including mangroves. More than sixty mangrove stands have been recognized in Hong Kong. Together with Kandelia obovata, a cold-tolerant mangrove tree, the red-clawed crab, Parasesarma bidens dominates the mangroves. Yet, there are much more flora and fauna waiting to be discovered. Our lab works on exploring the local mangrove biodiversity. We carried out intensive qualitative and quantitative surveys in the last two years, and updated the biodiversity database. A number of mangrove crabs and snails that are new to Hong Kong were recorded. An endemic species new to science, Haberma tingkok, was described recently as well.
Our lab is interested in understanding the proximate and ultimate causes of the conquest of land by brachyuran crabs. Recent studies found out that terrestrialisation is a recent but recurrent evolutionary trend in crabs, and we want to understand why and how many times this happened. To answer those questions, we study the physiological, behavioural and metabolic adaptation that help crabs to cope with the life in terrestrial environments as well as the role of associated microbiomes in such an evolutionary trend. We also aim to reconstruct the evolutionary history of such conquest of land, through phylogenetic analyses of both the involved crab species and their associated microbiomes.
Mangroves are present in tropical and sub-tropical regions of the world and are often exposed to an intense thermal stress. Due to the anthropogenic climate changes, the average temperature in the globe is rising, with the increase in climatic extreme events, and it is affecting the biology of several groups of animals. With the changes in the global temperatures, species from the mangrove fauna may have their life traits altered, and it can change the dynamics of the species in the community. Therefore, in the iMEco lab, we investigate the physiological responses of representatives of the mangrove fauna to the temperature. We try to understand the implications of the global warming to the mangrove fauna and how it could reflect on the mangrove ecosystems.
Due to the proximity to highly industrialised and urbanised areas, Hong Kong’s mangroves are exposed to toxic chemicals. Therefore, researching the nature, effects and interactions of harmful contaminants on these systems is crucial. Our lab has investigated the accumulation of heavy metals in mangrove sediments throughout 30% of Hong Kong’s mangrove stands and other research has assessed the bioaccumulation of metals within key plant and crab species.
We combine isotopic and ecological approaches to provide accurate trophic position estimates for the different invertebrate species populating the highly biodiverse and impacted mangroves ecosystem of Hong Kong. In particular, Laura Agusto, in collaboration with Dr Thibodeau of the Department of Earth Sciences of HKU, investigates macrobenthos food webs across a nitrogen gradient in Hong Kong territory using bulk stable isotope analysis. We also investigate whether these complex food webs can be better disentangled by using stable nitrogen isotopic composition of amino acids.