Freshwater ecosystem is an important habitat which encompassing less than 1% of the Earth's surface area but supporting an estimated 0.8% of all known animal species. This exceptionally high level of biodiversity indicates the importance of the freshwater ecosystem. However, these ecosystems are threatened by anthropogenic inﬂuences, including pollution, habitat destruction, overexploitation, and climate change which are progressively eroding their healthiness. Consequently, freshwater habitats are emerging as one of the most imperilled systems on the planet.

Flow regulation through damming is known to negatively affect biodiversity, disrupt ecological functioning, and reduce the genetic diversity of aquatic fauna. In Hong Kong, water catchment is a widespread conservation strategy, covering 33% of the territory. Over the years, the potential impacts of these catchments have become increasingly recognized. However, the speciﬁc effects of catchwaters on local freshwater ecosystems remain largely understudied. Therefore, this project aims to assess the impact of artiﬁcial catchwaters on freshwater ecosystems by examining the effects of water catchment on the community structure and ecosystem functioning of obstructed streams. Additionally, we investigate how artiﬁcial water catchments inﬂuence the genetic connectivity and diversity of targeted freshwater species. The ﬁndings from this project are expected to inform future rehabilitation efforts in Hong Kong by offering insights into how catchwater designs can be improved.

We are interested in how artiﬁcial catchwaters impact on freshwater ecosystems, such as the genetic connectivity and diversity of targeted freshwater species. We examined the effects of water catchment on the community structure and ecosystem

functioning of obstructed streams.