The burgeoning energy demand worldwide has led to a proliferation of hydroelectric dams, firstly in the northern hemisphere and subsequently across tropical developing countries, which have become the new hydropower frontier. Given the relatively flat terrain in lowland tropical forests, after damming, all low elevation areas are inundated, while previous ridgetops often become islands. Currently, hydropower development is one of the primary means of habitat loss and fragmentation in tropical forests, hence a key threat to biodiversity. In this symposium, we will synthetize the ecological impacts of habitat loss and insular fragmentation following river damming across tropical and sub-tropical forests. To do so, we invited a set of speakers currently working on these artificial insular landscapes who will present novel and timely research on a range of topics covering multiple biological groups (e.g., birds, mammals, ants and lizards). Six insular landscapes will be represented: Balbina and Serra da Mesa Reservoirs in Brazil, Kenyir Lake in Malaysia, Chiew Larn in Thailand, Gatun Lake in Panama, and Thousand Island Lake in sub-tropical China. Our overhanging aims are to form a team to work on a review paper summarizing such ecological impacts across artificial insular landscapes and proposing guidelines for biodiversity conservation and sustainable hydropower development. The symposium will start with an introduction explaining how dams are responsible for the fragmentation of terrestrial habitats in lowland forests and how those can be used to study the general effects of habitat loss and fragmentation worldwide. Then, we will focus on the biodiversity patterns across gradients of habitat loss and insular fragmentation, including taxonomic, phylogenetic and functional responses of invertebrates and vertebrates. This part will be important to illustrate species responses to habitat insularization across the six landscapes. We will then focus on rapid evolutionary changes in the aftermath of damming, particularly on lizard assemblages, and in the processes behind the patterns. The symposium will be closed with a synthesis of the current knowledge on the impacts of damming on biodiversity. This symposium represents a great opportunity for researchers working in these insular landscapes to get together and discuss about the long-term and ongoing research to be presented, some of them already gained international impact. Incidentally, research in this symposium covers many taxa, further addressing both the impacts of hydropower development and the wide topic of habitat loss and fragmentation, which will potentially attract a wide range of ATBC attendees.