Biodiversity
The Triumph of Adaptation
“It can be dizzying to get caught up in the species counts and checklists, but it is important to remember that this is about more than just numbers. Each single species represents an ancient evolutionary journey, a triumph of adaptation that has allowed it to avoid the numerous cliffs and cul-de-sacs of time that have claimed so many potential organisms. ”
When a country's foremost publication on common trees and shrubs can almost be used to anchor cruise ship or as ballast for a hot air: balloon, you know you're talking about serious diversity. A field Guide to the Common Trees and Shrubs of Lanka by M Ashton S Gunatilleke, N de Zoysa, M D Dassayake, N Gunatilake & and Is Wijesundera. (Colombo 1997) is this weighty tome, which contains detailed descriptions of 700 species. To add a dash of context to this dazzling figure, two average Kandyan home gardens have been recorded as containing 105 tree species, 68 shrubs species and 79 herb species.True, many of the trees and shrubs now proliferating in Sri Lanka were introduced from other parts of the world, however most of these - including such prominent species as jak (Artocarpus heterophyllus), nutmeg (Myristica fragrans) and areca nut (Areca catechu) - are now an integral part of the local scene. This is not to say that the island doesn't have its fair share of truly local diversity. After all almost a third of the 3,210 flowering plant species, 54/55 Dipterocarp species (which include many trees, such as hora, beraliya and dun that aroused extensively for construction), >40% of freshwater fish, >50% of reptiles and >80% of amphibians are endemic. There are also 66 species of orchid found only in Sri Lanka.
(territorial waters are 24 pelagic bird species while cavorting in the waves below are some 26 species (of whales and dolphins including the world's largest animal (blue whale - Balaenoptera musculus) and largest predator (sperm whale - Physeter macrocephalus). the docile dugong (Dugong dugong) inhabits the sea grass beds off the north west coast where it grazes peacefully, earning itself the nickname "sea cow" The most diverse part of the country, both in terms of plant and animal life- is the wet zone. Covering a mere 1/4 of the Sri Lankan landmass, this zone holds 88% of all, and 95% endemic, flowering plants. Most of the island's 140+ endemic amphibian species and 50+ endemic freshwater crab species are here, as are the majority ofthe23 or so endemic birds (just which of the island's avifaunal species are endemic is a keenly debated subject).
The montane forests 500m) and the- lowland rainforest are the richest of all. Both of these habitat types have been –largely decimated by intensive plantation-style agriculture and development. The upper reaches of the central hills have been forced to exchange their dense, finely-patterned blanket of mist-shrouded forest green for a thinner, inferior blanket of tea. The richly-textured original habitat is now best-exemplified by the Peak Wilderness Area the gnarled, stunted forests near Horton's Plains and the high slopes of the Knuckles range. The Sinharaja World Heritage site is the last remaining sizeable example of a lowland rainforest that once stretched from the south-west coast to the Badulla hills and south to Matara.
Less than 5% of this original-jungle remains, last glorious refuge for
countless^species/the diversity of which is still being revealed. As an example in 2001 a species of owl entirely new to science the Serendib scops-owl (Otus thilohofmanni) was identified in the dappled humid Sinharaja interior. Meanwhile, dozens of new species of frog, freshwater crab, snail and lizard have been described in the past several years by Bohan Pethiyagoda and his team at the Wildlife Heritage Trust (WHT), In 2005, it was proposed that what was once known as the mouse deer (Tragulus meminna), should be divided into two - possibly three - separate species based on skin characteristics and cranium size. The divisions run along climatic boundary lines with a dry zone and wet zone species and the potential third coming from the upper hills.
It is not only the more diminutive creatures that are unique. In fact, thanks to recent DNA analyst it has been determined that Sri Lanka is-home to unique sub-species of the largest mammal present walking the earth - the elephant (Elaphusj maximus). Not only is the Sri Lankan elephant genetically distinct from the Indian variety, it is, further sub-divided into two populations -Elaphus maximus villaliya or the swamp elephant, in the North, and Elaphus maximus maximus in the South. Adding further complexity, not to mention a great whack of mystery, is the fact that these two of sub-species each show greater genetic similarity to the Indian elephant (Elaphus maximus indicus) than they do to each other! the Sri Lankan leopard (Panthera pardus kotiya) is a genetically distinct sub-species and we are currently working to determine whether this genetic isolation has a behavioural and or ecological reflection. Even those playful scoundrel's, the toque macaques (Macaca sinica) are a race of monkeys unique to the island, and they are also further divided in to four regional sub-species. The burly purple-faced leaf monkey (Trachypithecus vetulus) - or bear monkey as the montane variety affectionately is another classically Sri Lankan mammal.
With this phenomenal bounty of floral and faunal species, It should come as no
surprise that Sri Lanka, together with the western Ghats of India, is considered one of Conservation International's 25 | global "biodiversity hotspots". .It can be dizzying to get caught up in the species counts and checklists, but it is important remoter that this is about more than just numbers. Each -singly species, represent ancient evolutionary journey; a triumph of adaptation that has allowed it to avoid numerous cliffs, and cul-de-sacs of time that have claimed so many potential, organisms. Like the variable beak sizes of Darwin’s famous Galapagos finches, which allow them to fill a range of niches within a small geographical area by feeding on different food types, Sri Lankan species are similarly finely-tuned to their fairly limited environment. Biodiversity is not just a catchphrase, but is important because it creates a certain ecological stability. Like a woven garment made strong by the numerous Individual threads, so an ecosystem's resilience is a result of the sum total of its individual component species. And like picking the threads from a garment the more specie that are lost-through exploitation, habitat loss and fragmentation the more fragile that, system - and the lives of those who depend upon it - become So revel in the wondrous array of patterns, hues, songs, tones and textures of Sri Lanka's natural diversity, but take cafe also to nurture and respect this diversity for while echoing the past it also represent the future.
