Chirixalus romeri is one of the 23 amphibians in Hong Kong which has a very narrow distribution in the world as it is endemic to Hong Kong. It is only found in the outlying islands in Hong Kong including Lantau, Lamma and Po Toi making them very susceptible to human disturbance or urban development. It is listed as endangered in IUCN red list 2008.
Recently there is a slope reinforcement work on Lamma Island that may affect a freshwater marsh holding a population of these tiny fragile frogs. Ex-situ conservation measures were conducted in order to reduce the impact on the natural population. There are several advantages for keeping them in captivity as it would not affect the gene pool and the competition of other population and it helps the scientists to know more about the ecology of the species including the breeding phenology and living conditions.
It's still unknown why Romer's Tree Frog is only distributed on the outlying islands but not Hong Kong Island and the New Terrestories. It's a matter of biogeography including plate tectonics and ice ages. However, too little is known in order to solve this complicated question.