International Day of Biological Diversity 2022: Not all urban greenery is created equal

The need to accommodate local biodiversity is pressing. Indigenous trees not only need much less care and can thrive without pesticides, but they also attract local fauna making up an ecosystem that supports varied species

Sumaira Abdulali
Published: May 20, 2022 11:50:49 AM IST
Updated: May 22, 2022 11:38:42 AM IST

International Day of Biological Diversity 2022: Not all urban greenery is created equalAutorickshaw driver Mahender Kumar drives his vehicle with a 'garden' on its roof, in New Delhi on May 2, 2022. Yellow and green autorickshaws are ubiquitous on New Delhi's roads but Mahendra Kumar's vehicle stands out—it has a garden on its roof aimed at keeping passengers cool during the searing summer season. Image: Money Sharma/ AFP

Outside my Mumbai window, a pair of sunbirds flashes in and out of the red-flowering Sita-Ashoka tree I had planted to replace a fallen gulmohar a decade ago. The gulmohar was one of eight exotic trees we lost on our tiny patch of roadside, and I mourned its spectacular beauty when it fell.

Green cover is recognised as essential to human health and well-being; urban greening is an important mitigation measure to slow climate change. But the right type of vegetation is crucial. Though all trees are beautiful, there is a special beauty to those local species which belong.

Palas trees ‘flame of the forest’ in the jungles of Central India are no less beautiful than a chinar tree in Himalayan Kashmir; wild ginger in the Western Ghats is as beautiful as wild roses in Himachal Pradesh or orchids in Sikkim. Each is suited perfectly to its own natural ecosystem and flourishes without human intervention.

Ordinary people in Mumbai have demonstrated their love of the natural in their years’-long struggle to save the forests of Aarey. Campaign leaders of the Save Aarey Movement include women and young people and even Maharashtra’s young Environment Minister Aaditya Thackeray, a passionate environment lover himself.

Ashok Kothari, former president of the National Society of the Friends of the Trees, who gave me the Sita-Ashoka sapling, said, “Replanting a lost tree is good. All trees absorb carbon and most foster birds and animals and increase urban biodiversity. But, unlike the exotics like gulmohar, indigenous trees like the Sita-Ashoka will flourish here for hundreds of years.”

The English ‘discovered’ the gulmohar in Madagascar in the 19th century. Its flaming orange once defined summer In Mumbai. But the gulmohar’s beauty is short-lived. Naturalised to a completely different climate and suited to dry, deciduous forests, gulmohar and other exotic trees fall in large numbers in the monsoon wind and rain. Sometimes they damage property and even endanger human life.

Other exotic trees like the eucalyptus, native to Australia and beloved of the koala bear which is endemic there, are inhospitable to local birds and animals in India.
Nevertheless, until 2009, the Garden Department of the Brihanmumbai Municipal Corporation continued to plant exotic trees, favouring them over local species. Non-native palm trees and African tulip trees became common in the public spaces of Mumbai. Their exoticness reminded people of holidays abroad and picture-perfect postcards of far-flung holiday destinations in other parts of the world.

As petitioners in the Bombay High Court, Awaaz Foundation submitted in 2009 that the Garden Department should use only local species for re-plantation of fallen trees. To compensate for those lost to development and otherwise, the court ordered that “the names of trees planted” should be stated on affidavit. In 2010, the Garden Department issued a list of native trees most suited to Mumbai.

Superintendent of Gardens Jitendra Pardeshi says, “In summer 2022, the Maharashtra state flowering tree ‘Pride of India’ adorns our roadsides with pink and purple flowers. It has become well understood they are far preferable to exotic species.”

Local trees are incomplete without natural undergrowth and wealth of shrubs, vines, creepers, grasses, wildflowers, and the beauty and biodiversity which make up a composite ecosystem.

Choosing to plant common local plants gives us a wide variety of choice--hibiscus, ixora, balsam, chameli, son-champa and a host of others which do not require constant care or pesticides. Unlike Hawaiian hibiscus or Singapore champa, local plants flower profusely, beautiful with just the right amount of water and sun found naturally here. This is the vegetation in which local birds and animals thrive best. The theme of International Day for Biological Diversity, May 22, 2022, is ‘Building a shared future for all life’.

Pardeshi says, “Local flora attracts local fauna, and, since these are naturalised to the climate of Mumbai, they need much less care. They thrive without pesticides and can survive almost without water even in summer, depending mainly on natural rainfall patterns.”

The need to accommodate local biodiversity is pressing. However, modern Indian cities have been transformed into concrete jungles, defined by cement-concrete and glass rather than greenery. Space to plant local shrubs and creepers is scarce.

Recently, Aaditya Thackeray inaugurated the first of BMC’s environmentally friendly bus stops with green roofs at Mahalaxmi. “You will soon spot these sleek bus stops in another 105 locations in the city & suburban Mumbai,” he tweeted.

Extensive rooftop gardens like those on the bus stops with a soil depth as little as two inches can support an array of local species of grasses and wildflowers.

Rooftop gardens with a greater depth of soil, ‘semi-intensive’ green roofs, can support shrubs, bushes and vines. Intensive green roofs with a deep soil can even support small trees. Together, they may complement local roadside tree species to encourage local biodiversity back into our cities and our daily lives.

Green roofs can insulate buildings and reduce their energy needs. They reflect sunlight and help reduce the urban heat island effect. They even help in stormwater management by capturing rainwater to keep it off the roads.

Rooftop gardening is not a new concept. Although we have never found physical evidence of their existence and only know of them through classical writings and oral history, the Hanging Gardens of Babylon, built in the 6th Century BCE and one of the seven wonders of the Ancient World, are one of the first known rooftop gardens.

In Mumbai, greening of rooftops is not a new concept either. The Hanging Gardens of Malabar Hill, overlooking the Arabian Sea, were built in 1881 to cover Mumbai’s main reservoir. The Gardens feature fountains and hedges carved into animals.

Not only public rooftop gardens but Mumbai’s gardens in commercial and residential buildings provide space for planting too, from a few pots on balconies and terraces to large podium gardens.

However, instead of taking advantage of the wide range of local plants found in India’s many biodiversity hotspots, farms and village gardens, developers who advertise forests, trees and birdsong in luxury developments often use exotic ornamental plants, unsuited to the areas and ecosystems in which they are planted.

Our own experiences in India highlight how alien plants like water hyacinths, brought to ornament ponds and lakes choke water bodies. Lantana is an invasive which strangles native shrubbery.

In countries like Israel and Dubai, drip irrigation systems have allowed verdant flower gardens to bloom and become a wonder of the desert. Such exotic gardens often require constant care and do not support the local biodiversity or ecosystems.

Many hybrid plants require human intervention to propagate and do not provide habitats conducive to birds, bees and butterflies. Outside of their natural habitats, hybrid and exotic plants are often delicate and prone to infections and may require regular use of pesticides and fungicides. Spraying plants with pesticides kills birds, butterflies and biodiversity.

According to the IPBES (2019): Summary for policymakers of the global assessment report on biodiversity and ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, “More than 75 per cent of global food crop types, including fruits and vegetables and some of the most important cash crops, such as coffee, cocoa and almonds, rely on animal pollination.”

Birds eat and spread fruits, nuts and seed new plant growth. Butterflies and bees collect nectar and pollinate flowers. Without the ecoservices they provide, the world’s agriculture and food systems would be severely threatened.

Bees’ high energy needs are met through flowers and plants which delight our senses “full of nectar” and “sweetly aromatic or have a minty fragrance”, according to the US Forest Service. Naturally flowering and fruiting plants are among the most beautiful of all.

Ecologist and educator Anand Pendharkar says, “Accessible biodiverse spaces such as the Maharashtra Nature Park and Aarey Forest allow youth to observe the interactions, interconnectedness and ecological services provisioned by natural biodiversity.”

Even in drought-prone and desert areas like California and Arizona in the US, gardens are developed with xeriscaping techniques which maximise the use of desert plants and rocks to create landscapes beautiful and appropriate to the desert.

In the fantasy world of Las Vegas, lawns are “outlawed, dug up and carted away” in the midst of alien man-made structures such as the Eiffel Tower. Instead, local species of plants such as the thousands of species of cactus and yucca indigenous to the Mojave Desert, are all set to replace water-intensive lawns.

As more people live in increasingly urbanised India, we wait and watch--along with other green initiatives such as solar panel subsidies, will the BMC consider a mandate for ‘extensive’ green roofs and gardens using local and indigenous plants or food plants rather than exotic ones? Which plants will our government choose for their own greening programmes?

Pardeshi says, “We called a meeting of all developers to educate them of the value of local flora recently. If developers start focusing on natural greenery native to this area, there will be a sea change in the landscape.”

Environments which nurture urban biodiversity may allow city-dwellers to experience the wealth of local plant and animal life in cities. It is only when people, especially children, interact with nature in their day-to-day lives that the true value and beauty of this biodiverse world becomes their lived experience, more direct and beneficial than theoretical learning. In their lived experiences, young people’s inspiration to protect the earth is fostered.

Pendharkar says that the children he teaches are instinctively amazed by the diversity exhibited by plants and animals. “Backyard forests such as SGNP act as learning laboratories for children who get inspired to understand natural design, undertake research and discover new and endemic species for themselves.”

Young people will suffer the effects of climate change most. Already, the effects of climate change are being felt in most parts of India and include prolonged and intense heat waves; increased landslides and floods; unseasonable rain and cyclones.

As our cities becomes even more built-up they become hotter and more polluted. Unlike trees, concrete and glass radiate and trap heat. Dense concentrations of cement-concrete buildings create urban heat islands where temperatures can increase by several degrees over their surroundings. According to the US Environment Protection Agency, “This effect increases energy costs (e.g., for air conditioning), air pollution levels, and heat-related illness and mortality.”

The effects of urbanisation are not only local. They spread and extend to surrounding rural areas and adversely affect farmlands and villages. Climate events increasingly affect the whole world. In a closed loop of destruction, these climate events are felling urban trees. Alongside our trees, biodiversity too is being lost at an unprecedented rate.

On May 5, a new study ‘State of the World’s Birds’ published in the Journal ‘Annual Review of Environment and Resources’ tells us that nearly half of bird species are in decline globally and nearly 80 percent are declining in India. Along with the birds, other species are being lost too.

Nearly 40 percent of Indians live in cities already and India is urbanising at a rapid pace. By 2050, the number of Indians in urban spaces will overtake those in villages, according to the United Nations.

“We point very clearly to the cities of the world as a key place for mobilisation,” said IPCC co-chair Debra Roberts in the sixth IPCC Report released in March 2022.

Recreating local biodiversity in our cities has more important benefits than ever before. Manali in the Himalayas cannot be recreated in Mumbai on the Konkan coast; the rainforests of the Andaman Islands cannot be recreated in the sand dunes of the Lakshadweep. Local and seasonal Indian weather is most suited to their own species and makes their own plants and their own ecosystems most beautiful.

Next door to Aarey lies the Sanjay Gandhi National Park, the only national park in the world where wild animals like leopards coexist with humans in the midst of an urban megapolis. A stand of Sita-Ashoka planted by Buddhist monks hundreds of years ago flourishes near the Kanheri Caves even now. Along with other local and indigenous trees they make up an ecosystem which supports varied species: Birds, insects, reptiles, squirrels and bats.

In the concrete jungles of our rapidly growing Indian cities, more greenery is better. However, not all urban greenery is created equal. Our own wealth of incomparable plants and animals found nowhere else in the world is the most beautiful. After all, there’s no place like home.

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