Current biodiversity of the fern and fern ally flora in urbanized Singapore
Professor Benito Tan of the Department of Biological Sciences, National University of Singapore (NUS), presented his study on the above topic which he had worked on with Ms Angie Ng of the Plant Group of the Nature Society of Singapore (NSS).
Their aim was to assess how urbanization has impacted the local fern and fern allies in Singapore 50 years after the publication of Fern Flora of Malaya by Dr R.E. Holttum in the late 1950s. His focus was on the remaining biodiversity of this plant group found today outside the primary and old secondary forested areas of Bukit Timah Nature Reserve and the Central Catchment Protected Area.
Based on the 2011 survey, they located indigenous as well as endangered ferns in areas outside of the nature reserves, namely in Admiralty Park and Punggol forest.
Additionally, a large amount of the endangered, but edible fern, Diplazium Esculentum, is growing in Bukit Brown cemetery – and Dr Benito says this is one more reason to push for the conservation of that area.
Surveying the fern and fern ally population in Singapore was not straightforward. A large problem he faced in his species identification and count was the presence of different variations of ferns in Singapore. The government has been bringing in cultivars with no discrimination – and because ferns hybridize very easily, it was not easy to identify the species here. For example, there are 3 types of birds nest ferns in Singapore; the Australian, native Singaporean and Japanese varieties.
They have also found two new fern species to be growing here; the Pleocnemia conjugata and the Adiatum Tenerum, as well as alien ferns, which originated from the United States – the Adiatum Latifolium and the Tecteria.
Twelve new fern species have been reclassified as endangered following his survey. In addition, a high extinction rate of between 41% – 44% amongst the fern and fern allies has been found, using Dr Holttum’s book as comparison. This is much higher compared to surviving seed plants here in Singapore.
Interestingly, they also found that outside of the nature reserves, there was greater biodiversity with 75 different species growing, while in the central catchment area, 60 species were found.
Dr Benito Tan highlighted three ways to prevent further loss to the already threatened biodiversity in this group of spore-producing plant life, namely; continual efforts to protect existing forests, rehabilitation of remnant forest patches allowing them to recover and restoration of former forest areas.