“I was surprised to see lilies blooming so early. Its right time to mature is during this season,” says Bikash Chettri, 26, an avid gardener, who has been continuing his hobby of pot gardening in his rented house at Tyanglaphat, Kirtipur.[break]
Bindeshwor Rai, senior officer at Godavari Botanical Garden, has more experience to share about the irregularities in flowering as well as increase in numbers of flowers which were otherwise impossible to grow in Kathmandu in natural environment.
Rai says that there has been considerable numbers of tropical plants that have been surviving in Kathmandu. Though the flowers which mostly grow in tropical environment used to bloom in Kathmandu for a certain time, now their life has considerably been prolonged.
Flowers such as musanda are new addition to the gardens in Kathmandu while others such as periwinkle, bougainvillea, Tulsi (Ocimum Temiflorum) and pothos (Epipremnum aureum) are those species which have expanded their life.
“Earlier, many tropical flowers could not live during winter, but they have been unexpectedly surviving Kathmandu’s cold weather,” he adds.
“The increase in growth of tropical plants in Kathmandu is due to the increase of heat in the city,” says Dr Tirtha Bahadur Shrestha, Nepal’s senior botanist. He points out that though the temperature of Kathmandu does not rise above the average of 32-34 degrees Celsius, the heat however remains for a longer period of time.
“Earlier, the peak temperature used to last only for a few hours, but now it’s as hot at nine in the morning as it is at noon. Even at night, temperature drops just slightly,” he says.
According to a report by Saraju K. Baidya et al from the Department of Hydrology and Meteorology, published in July 2007 and entitled “Climate Profile and Observed Climate Change and Climate Variability in Nepal,” the temperature in Kathmandu, the capital city, is increasing at the linear rate of 0.05 degree Celsius per year.
The report further mentions that “cold days and cold nights have become less frequent while hot days and hot nights have become more frequent.”
Due to such heat, early flowering is also witnessed in some plants such as marigold, rhododendron, phlox, aster, pansy, zinnia, and salvia.
“Flowers whose blooming period used to be May-June is now already seen during February-March while those that used to flower during March, has shifted to November-December,” says Shrestha.
He adds that in past years, even in summer, vegetation in Kathmandu used to be covered in mist in the morning, due to the drop in temperature during the previous night. But this hasn’t been witnessed since the last few years. Such absence of mist and the consistency of the high temperature have helped maturing of tropical flowers in the Kathmandu Valley. “These are the effects of local as well as global warming,” he says.
Dr Annapurna Nanda Das, Director General of the Department of Botany, Ministry of Forests and Soil Conservation, also perceives the growth of tropical flowers in Kathmandu as an effect of climate change. Rainfall pattern and the rise in temperature along with various evidences of climate changes in global context compel him and his experts to conclude so, says Das.
“Nowadays, rudrakshya (Utrasum bead), which is said to grow efficiently in humid regions between 500m to 1000m above sea level, matures well in Kathmandu as well. And Kathmandu is 1,400m above sea level,” says Das. Also, he claims that the distribution range of the plants has shifted slightly upward from the sea level.
Apart from flowering plants, some tropical trees also have started to subsist in Kathmandu. Rai names the Ashoka Tree (Sarca Indica), Rajbrikshya (Cassia fistula) and silver date palm (Phoenix sylvestris) as some of those specimens.
He adds that mango trees in Kathmandu, which earlier used to yield sour fruits, have now started bearing tasty mangoes, like of those found in the Tarai. Neem (Azadirachta Indica), which is known for its medicinal values, has been surviving in the Valley since the past three years.
“It’s not healthy for plants to grow elsewhere due to temperature fluctuations. Natural components coexist in a system, and when any of the factors deviates, it’ll harm the whole ecosystem,” says Shrestha.
When there is an early flowering of plants, the insects that help in pollination of those flowers may not be ready at that time. Insects such as bees and butterflies will also be equally affected in that process, according to him.
Das mentions that plants may suffer from physiological stress in such cases. There are also chances of plants getting infected by diseases due to lack of ideal conditions for their survival.
In addition, farmers who rely on vegetation will also get affected in course of shifts in survival of plants due to changes in natural conditions.
However, people will be aware of the adverse effects of climate and its consequences on those plants that are associated with their livelihood.
“But those plants which don’t have direct involvement with livelihood are in danger of getting extinct,” Das shares his concern.
The evidences of extinction of some of the plants have already surfaced, and are under further study.
“We’ve singled out some of the plants that are already extinct and on the verge of extinction. But since the research hasn’t yet been completed, we’re yet to check the facts,” says Dolraj Luitel, assistant research officer at the Department of Botany.
Such irregular blooming of flowers and its relation with climate change has been evident. But according to Das, these are only based on visual observation.
“A scientific study that declares the correlation hasn’t been carried out,” he says. But he is quick to add that a team has been sent to Ilam and Khaptad to carry out similar investigations.
“We’re planning to research the existence and survival conditions of the endemic species of Nepal. And for that, we’re looking forward to collaboration with other agencies working on vegetation and climate change issues,” adds Das.
Kamal P Aryal, agriculture specialist and natural management analyst at the International Centre for Integrated Mountain Development (ICIMOD), says that the abnormalities in flowers are initial indication of future consequences of climate change. He states that there is an increase in the number of mosquitoes this summer in Kathmandu due to a rise in heat.
“Likewise, if tropical flowers bloom in a temperate zone like Kathmandu, the pollinating insects will also migrate, according to their need. Though that may seem trivial now, the whole ecosystem can be disturbed accordingly,” he warns.
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