Meeting Abstract
34.4 Friday, Jan. 4 High genetic divergence among Hong Kong stream faunal populations: Implications for biodiversity conservation of freshwater ecosystems CHU, K.H.*; TSANG, L.M.; WU, T.H.; The Chinese University of Hong Kong; The Chinese University of Hong Kong; The Chinese University of Hong Kong kahouchu@cuhk.edu.hk
Freshwater organisms generally exhibit much more pronounced genetic structuring than their marine counterparts. While understanding the level and spatial distribution of genetic diversity is crucial for conservation management planning, such information have received little attention until recently in highly developed cities like Hong Kong and Singapore, where local extinction caused by habitat loss and degradation is severe. Here we compared the genetic divergence in mitochondrial genes of common freshwater fauna, represented by nine species of fishes and five species of invertebrates, collected from more than 20 streams in Hong Kong covering a land area <1,000 km2. Surprisingly, except in three species of fishes, all species exhibit pronounced genetic architecture, with population in each stream frequently having its own unique haplotypes, even though some of the streams are separated only by a few kilometers. Moreover, genetic diversity within each stream is very low, usually with a single haplotype dominating the entire population. This reflects a low effective population size commonly observed in fragmented populations. The congruence in population subdivision observed across fauna suggests long term isolation among streams. Since conservation measures are often only considered long after urban development has begun, unexpected high genetic diversity of freshwater fauna over short distances has significant conservation implications as a substantial amount of biodiversity may have already been lost due to past development. Careful conservation planning of freshwater ecosystems is needed for future development in Hong Kong and elsewhere.
