Diversity and conservation of Hong Kong bryophytes
Abstract of thesis entitled
DIVERSITY AND CONSERVATION OF HONG KONG BRYOPHYTES
for the degree of Doctor of Philosophy
at The University of Hong Kong
in June 2001
Despite a land area of only 1,100 km2 and a long history of severe human impact, Hong Kong still supports a surprisingly rich native biota. The bryophyte inventory was updated by detailed and systematic field surveys throughout the whole of Hong Kong, examination of my own collections and some historical specimens, and reviewing the relevant literature. The updated inventory includes 353 species and 12 infraspecific taxa in 69 families and 157 genera. Four families, 19 genera and 48 taxa are reported as new additions to Hong Kong, of which Syrrhopodon hongkongensis is new to science; the genus and species Eccremidium brisbanicum and species Barbella convolvens are new to China; and four species: Acroporium secundum, Leucophanes glaucum, Mitthyridium fasciculatum, and Syrrhopodon spiculosus, are new to mainland China. Ectropothecium nervosum was reduced to a synonym of E. zollingeri. Nineteen previously reported species are excluded from the local flora and 27 species are treated as doubtful records.
Bryophytes were sampled from forty-seven 16 m2 plots in a wide range of habitats. Forest plots had most species (mean 18.4), while feng shui woods, shrubland, grassland, agricultural areas, and urban areas had fewer species (mean 2-3.5). Multivariate analyses of the plot data, including cluster analysis and Non-metric Multidimensional Scaling, showed that the most important environmental variables controlling bryophyte diversity and species composition are habitat, altitude, and north/south aspect. The number of species per forest plot increased linearly with altitude (r = 0.948).
Fourteen phytogeographical patterns were recognized in the Hong Kong bryoflora. Overall, the bryoflora is northern marginal tropical, but East Asian and temperate patterns are also important. Comparison with the bryofloras of 23 countries and regions showed that Hainan, Taiwan, and Japan were most similar. Mosses and liverworts showed slight phytogeographical differences.
One hundred and twenty-seven taxa of mosses and 16 moss hot spots were identified as of conservation importance. There was insufficient data to do a similar analysis for liverworts and hornworts. Two categories, Local Restrictedness (LR) and Overall Conservation Status (OCS), were used to indicate rarity and conservation importance. Sixteen taxa of mosses are probably locally extinct. The density of rare, very rare, and threatened taxa is much higher at high altitudes than in the lowlands, and they occur more often than expected on north aspects. Eighty-seven threatened taxa (73.7%) were found entirely or largely within protected areas, and 31 (26.3%) entirely or largely outside. All the identified hot spots are either within formally protected areas or are safe in places with steep and inaccessible topography.
At present, the threats faced by local bryophytes are minor, but increasing regional air pollution and global warming may be significant in the long term. Recommendations for the conservation of Hong Kong bryophytes include setting up protected sites outside of the current conservation areas, reducing pollution, including bryophytes in Environmental Impact Assessment (EIA), training local bryologists, and increasing public awareness.
School:The University of Hong Kong
School Location:China - Hong Kong SAR
Source Type:Master's Thesis
Keywords:bryophytes china hong kong classification ecology biological diversity conservation
Date of Publication:01/01/2001