Visit our home page at bristol.ac.uk/botanic-garden/

Monday, 5 August 2013

Plants that endure

by Helen Roberts

Whether perched upon a windblown cliff or nestled in a small crack deep within a canyon, some plants seem to overcome all odds of survival. These survivors, which are frequently rare, quite often grow in remote inhospitable environments, show true resilience and perseverance and are highly adapted to their specific habitats. You just have to admire them for their sheer tenacity.

However, some of these ‘bulldog’ plants aren’t the hardy-looking brutes one might expect of such survivors; sometimes they are delicate and very beautiful. Discoveries of plants such as these are occurring regularly with over 2,000 new plant species being found worldwide each year. Many are found in far flung areas of the globe, as well as on our very own doorstep here in Bristol.

A Malaysian beauty


The newly described Ridleyandra chuana with a
rare two flowers. Photo credit: L.S.L. Chua
A rare and endangered endemic plant found in the biologically diverse Pennisular Malaysia has recently been described. The beautiful plant is called Ridleyandra chuana and is only found in two small mountainous areas of forest.

The plant can be simply described as a perennial herb that is somewhat woody with a rosette of dark hairy leaves at its base. It has a long slender unbranched stem with very delicate and beautiful cone like flowers, which are white with dark maroon purple stripes.

This herb grows in very challenging habitats, such as moss covered granite rock emdedded in soil or moss covered granite boulders in extreme damp and shade on steep slopes.

The maroon/purple cone-like flower of
R. chuana. Photo credit: L.S.L. Chua.
The plant was initially discovered back in 1932 at Fraser’s Hill, Pahang, but only recently have enough data been collected to formally describe the plant. It is named after botanist and conservationist Lillian Swee Lian Chua who discovered another population whilst carrying out a biological inventory of summit flora on Gunung Ulu Kali, Pahang. Because of its limited numbers (only 130 individual plants are known to exist) it has been classed as Endangered under the IUCN criteria. Of the two locations of where it is found, one location is threatened.

"The population at Fraser's Hill falls within a Totally Protected Area and consists of about 30 plants that grow in an undisturbed site away from tourist trails and is too remote to be affected by development,” said Dr Ruth Kiew, author of the recent study describing this exquisite plant. “The other population consists of less than 100 plants at Gunung Ulu Kali, which is on private land in a hill resort that is severely threatened by road widening and associated landslips, by changes in microclimate due to edge effect as the forest becomes more and more fragmented and that is in danger of encroachment from future development. The chances of this latter population surviving is very slim. On the other hand, the rediscovery of the Fraser's Hill population after a hundred years illustrates the resilience of species to survive if the habitat remains undisturbed."

A beauty closer to home


Such rare and endangered plants that cling to life in the most inhospitable places are also found not too far from Bristol Botanic Gardens and are now being displayed at the Gardens as part of their ‘ex-situ’ conservation collections. The Avon Gorge, a Carboniferous limestone gorge cut out by the River Avon provides a sheltered microclimate of sun-baked niches for a wide variety of endemic species within ancient scrub and grassland communities. Many of these species are threatened by scrub invasion, introduced species and engineering works. Of these rare species, there are two endemic whitebeams, Sorbus bristoliensis and Sorbus wilmottiana that literally cling to life in the Gorge. 

They are being grown at the botanic gardens and also a number of newly discovered and described endemic whitebeams are currently being cultivated to add to the existing whitebeam collection. Wilmott’s Whitebeam (Sorbus wilmottiana) is listed by the charity Plantlife as one of our 10 most threatened woodland plants in the UK, which is why ex-situ populations are so important in helping to understand species and aid in the long term management and future development of the AvonGorge. The study and protection of rare plants is beneficial in the long run not only to the individual species, but also the plant communities to which they belong. 

No comments:

Post a Comment