SOME BUTTERFLY SPECIES HAVE DWINDLED



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By Ifham Nizam
Pictures courtesy Rajika Gamage  


Entomologists, those who specilise in insects strongly believe that when comparing early records to the present distribution of butterfly fauna especially here in Sri Lanka, some species have dwindled.


In other words, butterfly populations are restricted to limited areas due to declines in forest vegetation and fragmentation. Needless to say, the rapid decline of rain forests in the last century is the main cause for the decline of most of endemic species.


Scientists point out that there is an urgent need to take immediate action to conserve our native, particularly endemic butterflies.


It is imperative to identify butterfly hotspots and declare them conservation areas to preserve the remaining population.


Hats off to the painstaking initiatives of Dilmah Conservation especially when it comes to ex situ conservation programmes like butterfly parks, breeding programmes and recognizing the need to indentify and propergate the food plants of butterfly larvae.


It is also important to gain knowledge of the life cycle of rare butterfly species to identify the food plants of larvae and the nectar yielding plants of the adults.


Today, Dilmah Conservation will host a free workshop at the MJF Centre in Katubedda, Moratuwa. The workshop would commence at 9.00 a.m. titled ‘Growing a Butterfly Garden’. The workshop will be conducted by the Dilmah Conservation team and lead by Naturalist and butterfly expert, author Rajika Gamage.The workshop will feature an interactive session in Dilmah Conservation’s very own Butterfly Garden, teaching participants how to make urban gardens butterfly friendly and the benefits of attracting butterflies to your garden. 


Dilmah Conservation’s urban open-air Butterfly Garden is the first of its kind here. Since its construction in October 2011, it has provided a safe haven for a growing list of butterfly species. Currently some 53 of the 247 species of butterflies observed in Sri Lanka have been sighted within the gardens.


Butterflies are picky egg-layers and exclusive in their host-plant choice. Their presence is often bound to a combination of preferred host and nectar plants. Dozens of plants were selected with the help of entomologists and botanists to attract a wide range of butterfly species to the gardens and provide them with a suitable breeding ground. Particular attention was paid to attracting threatened or endangered species.


Over the years the Dilmah Conservation butterfly garden, although relatively small (750m²), has attracted hundreds of butterflies and proved to be an excellent conservation tool. Since the butterfly garden is situated within an extremely urbanized landscape in Moratuwa, it has acted as critical refuge for not just butterflies but other insect, bird, and reptile species found in the region.


Rajika’s biggest passion is to contribute to species conservation, both fauna and flora. But along with birds, butterflies top his list.


In 2011, together with Dilmah Conservation, Gamage created an urban butterfly park on the site of what was once a garbage dump for a clothing company.


While many conservationists doubted the viability of a butterfly garden in an urban setting, a determined Gamage worked with his team to convert some 660 square meters (7,080 square feet) of stinky marsh into a butterfly sanctuary. With six inches of new soil, the plot was soon landscaped to create a butterfly garden  in Moratuwa.


Here, even on the cloudiest day, more than 15 species of butterflies can be easily observed, with more than 60 species recorded since its opening in 2011.is a Nymphalid butterfly known for its spectacular shaded blue wings. With wings closed, it closely resembles a dry oak leaf.


"Butterflies are facing rapid extinction and need creative conservation methods," he says. "In Sri Lanka, there are butterfly houses with an indoor setup. We envisaged a conservation model with an open environment — without any form of species in captivity."


Rajika studied suitable host plants and nectar plants for creating a "walk-through" sanctuary, now extremely popular with children and researchers alike. Next, some 70 host plants and 20 nectar plants native to Sri Lanka were introduced to create the habitat. While some butterfly species have a single host plant, others have a few.


"In choosing species, we eliminated those requiring special conditions for survival, such as forest habitats,"he says. "In the very first month, we recorded five species [of butterflies], and within six months, about 12. Within the first one and a half years, we recorded over 50 species and significant butterfly populations." endemic butterfly species restricted to cloud forests of Sri Lanka’s Central Highlands.


The butterfly presence eventually stabilized, with about 15 species a day, including seasonal migratory species. A few threatened species and more widespread ones, like the common tiger butterfly (Danaus genutia), are regularly sighted here. "It is now a sustainable ecosystem," says Prasad Tharanga, arboretum coordinator at Dilmah Conservation. "It is important to maintain sufficient sunlight, plant height and the micro habitat for species survival."


The garden, besides forming a natural habitat for the more common butterflies to reside in, offers a perfect setting for learning about the insects. the Sri Lanka Tree Nymph is endemic to Sri Lanka.


He says butterflies are more important as an indicator species than as a pollinator. "Bees are better pollinators while butterflies are more important as an ‘indicative’ species. They are found in rich habitats with high levels of diversity, especially plants," he says.


 
 
 
 
 
 
 
 
 
 
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