Factors affecting the early survival and growth of native tree seedlings planted on a degraded hillside Grassland in Hong Kong, China

The effects of seasonal drought, belowground competition, and low soil fertility on the survival and growth over 2 years of four native tree species planted on a degraded hillside grassland in Hong Kong were studied in a field transplant experiment using three-way analysis of variance. The tree species were Schima superba (Theaceae), Castanopsis fissa (Fagaceae), Schefflera heptaphylla (Araliaceae), and Sapium discolor (Euphorbiaceae), and the treatments were dry season irrigation, herbicide, and fertilizer. Each species responded differently to the treatments. Sapium had a very low survival rate as a result of wind damage at the exposed study site. All three treatments significantly reduced the survival rate of Castanopsis seedlings, whereas herbicide reduced it for Sapium but increased it for Schefflera. The significant effects on seedling growth were all positive, except for a strong negative effect of herbicide on Castanopsis growth. Overall, the results suggest that all three factors- seasonal drought, belowground competition, and low soil nutrients-can significantly impair seedling growth on a degraded hillside site in Hong Kong but that their relative importance differs among species. The growth benefits of the three treatments were largest and most consistent for Schima, which as a mature forest dominant would be expected to be particularly sensitive to the environmental conditions on degraded open sites. This study highlights the fact that more systematic planting trials are needed to identify suitable native tree species for cost-effective reforestation on degraded hillsides in Hong Kong and South China.postprin

Natural regeneration in exotic tree plantations in Hong Kong, China

Tree plantations consisting mostly of a single exotic species have been established in Hong Kong, South China, for reforesting degraded lands since the 1950s. In this study, natural woody plant regeneration success under different types of closed-canopy plantations (Acacia confusa, Lophostemon confertus, Melaleuca quinquenervia and mixed-plantings) and natural secondary forests in the central New Territories were assessed. A total of 79 tree species, 64 shrubs and 23 woody climbers were recorded in 16 20 m × 20 m plantation plots. Stem density of woody plant regeneration was similar among all sites, ranging from 9031 to 10,950 stems > 0.5 m in height per hectare. Multivariate analysis of understorey species composition showed that there were consistent differences between plantation types. Lophostemon plantations generally had poor native plant colonization in comparison with natural secondary forests and other types of plantations. These differences between forest types can be at least partly attributed to pre-existing site conditions, since the tree species planted were matched to the site. Native woody plant colonization was poor on sites isolated from natural seed sources. Plantation understories were generally dominated by a few species of bird-dispersed shrubs, suggesting that enrichment planting with poorly dispersed shade-tolerant native tree species will be needed to facilitate regeneration in those plantations where natural regeneration is inadequate. © 2005 Elsevier B.V. All rights reserved.postprin

Seed rain into upland plant communities in Hong Kong, China

Hong Kong is an extreme example of tropical landscape degradation, with no substantial remnants of the original forest cover and a highly impoverished disperser fauna. Seed availability is a potential limiting factor in vegetation recovery in such landscapes. To assess the quantity and quality of the seed rain of woody taxa, seed traps were placed in the major upland vegetation types: fire-maintained grassland, shrubland, and secondary forest. Within the grassland site, traps were placed under isolated trees, isolated male and female shrubs of Eurya chinensis, and in the open. Seeds were collected every 2 weeks for 2 years. The seed rain was highest under female shrubs in grassland (6455 seeds m -2 year -1), where it was almost entirely confined to their fruiting period. Next highest were isolated trees (890 seeds), followed by male isolated shrubs (611 seeds), shrubland (558 seeds), forest (129 seeds) and open grassland (47 seeds). The number of seed taxa was highest in shrubland (59), followed by isolated trees (42), forest (42), female isolated shrubs (28), male isolated shrubs (15), and open grassland (9). The seed rain differed in species composition between the forest, shrubland, and grassland sites, while the differences within the grassland site were largely in terms of quantity. Birds (particularly bulbuls, Pycnonotus spp.) are known or inferred to be the major dispersal agents for 85% of the seed taxa trapped, 99% of the total number of seeds trapped, and 99.8% of the seeds trapped in the grassland site. Few taxa and <1\% of the total seeds were dispersed by wind and no seed taxa were definitely dispersed by fruit bats. The results suggest that even in the most degraded landscape the seed rain is adequate for the development of woody vegetation cover, but that human intervention will be needed for the restoration of plant diversity. © Springer 2006.postprin

Managing amphibians in agricultural wetlands in South China: effects of fertilizers on Tadpole Performance

Abstract no. 0192 SSAR Siebert Conservation Award, Session IpostprintThe 2011 Joint Meeting of Ichthyologists and Herpetologists, Minneapolis, MN., 6-11 July 2011

Impacts of illegal trapping on endangered big-headed turtles (Platysternon megacephalum) in Hong Kong

Abstract no. 0178 SSAR Seibert Conservation Award, Session IIpostprintThe 2011 Joint Meeting of Ichthyologists and Herpetologists, Minneapolis, MN., 6-11 July 2011

Status update on White-eared Night Heron Gorsachius magnificus in South China

White-eared Night Heron Gorsachius magnificus is probably the most threatened heron species in the world, and the highest priority for heron species conservation. From 1990 to 1998, there were sightings from only six localities in the wild. There are none in captivity. In 1998 a caged bird was found in a wildlife market in the city of Nanning, Guangxi Zhuang Autonomous Region, People's Republic of China. This finding prompted a 12-month survey in 1998-1999 of both markets and potential habitats in Guangxi. Several captured birds provided direct evidence of the existence of small populations in Guangxi and Guangdong Provinces. The respective habitats were surveyed in spring 2000, with emphasis on observations at dusk. The species was seen at two locations. Although some of the captured birds came from highly degraded habitat, the best sites seemed to be in areas near extensive primary forests, with streams, rice fields and marshes. The information obtained will be used to compile a detailed Action Plan designed to prevent the extinction of the species.published_or_final_versio

Woody plant regeneration on roadside slopes in Hong Kong, China

Conference Theme: Assessing and Restoring Biodiversity in a Human Dominated Landscap

Nodulation of native woody legumes in Hong Kong, China

Woody legumes can play an important role in forest restoration on degraded land but the knowledge of woody legumes has lagged behind their uses. This study is a pioneer investigation to explore the ability of native woody legumes to form root nodules and fix nitrogen in Hong Kong. Nine sites of different habitat types were surveyed during both wet and dry seasons for two years. Young plants of woody legumes along studied transects were excavated. The patterns of nodulation and nodule morphology were recorded and the nitrogen fixing ability was tested by acetylene-reduction-assay. Twenty-eight species in 16 genera were examined, of which 20 species were nodulating and eight non-nodulating, including all six species in the Caesalpinioideae. Five species were new records to the world's nodulation inventory. Bowringia callicarpa was a new species and genus examined, which was non-nodulating. The overall nodulation pattern was consistent with previous studies. Nodulation was more profuse in some shrub species while inconsistent in most tree species. Species with higher proportion of nodulated individual plants also tended to have more nodules in each plant. Spherical nodules were common in shrub and woody climber species whilst tree species usually had woody indeterminate nodules. Seasonal difference in the amount of senescent nodules was noted in most species. All the nodules tested by acetylene-reduction-assay were effectively nitrogen-fixing, with nitrogenase activity ranging from 4 μmol C2H4 g-1 h -1 to 20 μmol C2H4 g-1 h -1, which was comparable to other tropical tree species. The findings in nodulation pattern and nitrogen fixing ability of these species are essential in their application in forest restoration on degraded lands. © 2008 Springer Science+Business Media B.V.link_to_subscribed_fulltex