Population genetics is a tool that conservationists have continued to rely on to quantify population-level genetic variation and identify priority conservation units. The range-wide deforestation starting in the 1600s and rapid urban development and associated habitat modification in recent decades have posed significant challenges to the Hong Kong newt (Paramesotriton hongkongensis), a tropical salamander restricted to streams and forests in southern China. Our research, which sampled 310 adult P. hongkongensis from 10 breeding streams throughout its current distribution in Hong Kong, China to quantify genetic diversity and characterize its population genetic structure using 9 pairs of SSR primers, has revealed crucial insights. Despite long-term, repeated disturbance to its habitat and fragmentation caused by urban development, genetic diversity has been maintained within and among P. hongkongensis populations. Only two out of ten sites exhibited evidence of population bottlenecks. Bayesian clustering revealed five well-supported clusters within the range of P. hongkongensis in Hong Kong, which should be managed as separate conservation units. This work adds to the existing evidence that the effects of urbanization and human disturbance on genetic diversity in amphibians are not easily generalizable and should be addressed on a case-by-case basis.

Freshwater biodiversity is declining dramatically, and the current biodiversity crisis requires defining bold goals and mobilizing substantial resources to meet the challenges. While the reasons are varied, both research and conservation of freshwater biodiversity lag far behind efforts in the terrestrial and marine realms. We identify fifteen pressing global needs to support informed global freshwater biodiversity stewardship. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated action towards its sustainable management and conservation.

Forest loss is a major environmental threat in the Anthropocene. Repercussions are rarely localised and often impacts adjacent ecosystems. For example, forest loss is generally detrimental to freshwater biodiversity. There are however, some uncertainties about its effects on food webs and ecosystem functioning. We tracked changes in the food webs of four tropical stream catchments (two time points separated by a ~20-year interval) affected by varying degrees of forest loss. Our data show that the proportion of assimilated terrestrial organic matter (allochthony) remained largely invariant, but changes in food chain lengths inferred from the trophic positions of apex predators (TP) differed between catchments. Here, we found that higher rates of forest loss resulted in more significant reductions in TP. We speculate that the mechanisms involved are unrelated to diminished terrestrial subsidies as allochthony values were low (~7%) and did not shift in response to forest loss.