Urban Green Spaces: A Tool for Sustainable development and Biodiversity conservation

Chandramika Nath

Photo: Udayan Borthakur

"Urbanization" is the term that is gaining traction nowadays. Everything is gradually becoming "Urbanized," and we are dealing with issues such as human-wildlife conflict, disease, climate change, and many others. Coexistence and sustainable development are concepts we hear in our daily lives in today's world. Humanity is increasingly urbanizing, and by 2030, more than 60% of the world's inhabitants are expected to live in cities (UN, 1997). But even as society becomes more urbanized, we remain as reliant on nature as ever. In this period of rapid urbanization, understanding urban ecology has become critical. We know that ecology is the study of organisms' distribution, abundance, and behavior, as well as their interactions with one another and with their environment, whereas urban ecology is the ecology of all organisms, including humans, in urban settings as well as habitats impacted by city development, growth, and operation, such as forested watersheds (catchments) that provide drinking water to urban residents. It involves humans because people's presence, population dynamics, and behavior, along with the environmental changes that occur when they build towns and cities, are critical to our knowledge of how urban systems work. Some authors also use the term urban ecology to designate an interdisciplinary field that combines natural sciences, social sciences, and humanities. Urban ecology is fascinating for a variety of reasons, including the fact that urban environments are vast and expanding, their ecology is inherently intriguing they are ideal for testing and developing ecological theory, and the nature of urban environments affects the health and well-being of their human inhabitants, and they are important for conserving biological diversity.

With the quickening pace of urbanization forest cover or green space has been reducing, habitat destruction, fragmentation and wildlife species are declining. Only the generalist species that can adapt in urban areas are thriving whereas specialist species are quickly diminishing. However, urban settings can also be home to many species, opportunistic species that may survive if given the right habitat, and urban green space plays an important role in this. Urban ecosystems comprise mosaics of habitats including forests, grasslands, formal parks and gardens, churchyards, incidental greenspace, private gardens, and wetlands, as well as numerous ecological processes that determine their functioning. Urban green space is an umbrella term for all the many natural and man-made urban habitats and their ecological processes. Although humanity is becoming more urban, it nonetheless relies on nature for survival. Street trees, lawns/parks, urban forests, cultivated areas, wetlands, and streams, among other things, provide a variety of ecosystem services. Ecosystem services are described as "the benefits that human populations derive from ecosystem functions, either directly or indirectly." There are various ecosystem services provided by urban green space, a few having major importance such as air filtering, micro-climate regulation, noise reduction, rainwater drainage, sewage treatment, and recreational or cultural values etc. Air pollution from vehicles and building heating, among other things, is a major environmental and public health issue in cities. Vegetation helps to reduce air pollution, but the location and structure of the vegetation are critical for its effectiveness in filtering the air. According to Bernatzky (1983), up to 85% of air pollution can be filtered out in a park and up to 70% in a street with trees.

Photo: Udayan Borthakur

The city has an impact on the local climate and weather. For example, consider the urban heat island effect, which is created by the enormous area of heat-absorbing surfaces in cities combined with high energy use. However, the temperature in the surrounding countryside is still lower. We are aware of the heat island effect to some extent because we can experience it in Guwahati city, where the air temperature is higher inside the city but lower in the city outskirts. As a city inhabitant, you may notice individuals traveling outside for vacations, nature walks, and so on. All natural ecosystems in urban areas will help to lessen these inequalities. Water areas in the city will help to level out temperature variations in both summer and winter. Vegetation is also significant. A single tree may transpire 450 l of water every day. In addition, by shading dwellings in the summer and reducing wind speed in the winter, vegetation can also significantly reduce energy demand for heating and air conditioning in metropolitan areas. They also help to minimize noise to some extent. People in cities suffer from health concerns caused by noise from traffic and other sources.

Another big concern in metropolitan areas is stormwater drainage. Our city frequently floods during the rainy season. Vegetation and water bodies help to solve this problem in a variety of ways. Water can seep through the soft earth of vegetated areas, and plants absorb water and release it into the air through evapotranspiration, while water bodies store the water. The Brahmaputra River and Deepor Beel are important in the case of Guwahati. Deepor beel serves as a reservoir. Wetlands also assist in the treatment of sewage water. Wetland plants and animals can absorb enormous amounts of nutrients while also slowing the flow of sewage water and allowing particles to settle to the bottom. Wetlands are also home to a diverse range of wildlife for example Deepor Beel has a rich avian diversity. Aside from all of these services, the recreational components of all urban ecosystems, with opportunities to play and rest, are likely the most highly appreciated ecosystem service in cities, as a city is a stressful environment for its residents.  Green landscapes are also psychologically significant.  Cardiovascular disease and mental health issues are two of the most serious public health issues confronting metropolitan populations in the twenty-first century. Approaches to dealing with these issues in public health may be 'downstream,' focusing on treating symptoms of illness through the acute healthcare system, or 'upstream,' focusing on creating the social, economic, and environmental conditions that promote health and prevent illness and disease. The impact of urban ecosystems on 'upstream activities' in public health can be significant.

Urban ecosystems are intrinsically tied to the provision and maintenance of the wide environmental conditions that are essential to cities' viability. Urban green space provides opportunities for urban residents to be in contact with the natural environment and contact with urban greenspace can also help to alleviate stress, restore attention capacity, and provide opportunities for people to self-regulate their emotions. People who are in passive contact with, or physically engaged in, urban surroundings that aren't perceived as threatening can benefit from both physical and psychological health benefits. Contact with urban greenspace may improve life expectancy and self-reported health regardless of people's socioeconomic status. A Research study on hospital patient recovery found that patients in rooms facing a park recovered 10% faster and used 50% less powerful pain-relief medicine than patients in rooms facing a building wall (Ulrich, 1984). The urban ecosystem can also serve as an indicator of the state of the urban environment. Lichens, for example, cannot grow in contaminated air and can thus be used as indicators of air quality.

Photo: Udayan Borthakur

In addition, Urban green spaces play a crucial role in promoting biodiversity and supporting human welfare. Urban green spaces are vital for preserving remnant natural habitats and providing a natural habitat for plants, animals, fungi, and microorganisms in urban areas, making them essential for urban biodiversity. For example Assam State Zoo cum Botanical Garden campus, a tiny patch of wilderness is a veritable treasure trove of biodiversity, housing a fabulous array of flora and fauna ((Manoj V. Nair, 2006). There are other examples also, such as the Garbhanga Reserve Forest, Amsang Reserve Forest, etc. which are home to a diverse range of flora and fauna.

Even a single tree can harbor many species, from small insects to birds, etc. For example, the old trees of the Dighalipukhuri area provide shelter for many birds. The major roosting site of fruit bats, black kites, common crows, egrets, etc. I find it so peaceful just to look at them going back to their nests and bats going out foraging and I hope many people do.  And the fringe areas harbor more biodiversity in nearby Guwahati City.

Photo: Chinmoy Swargiary

Cities can be rich in biodiversity. Furthermore, urban green spaces can be intentionally designed to increase biodiversity, improve human interaction with nature, and provide ecosystem services, contributing to sustainable urban development and human well-being. The application of ecological knowledge is central to maintaining the structure, complexity, and composition of urban habitats that are necessary to meet both human aesthetics and nature conservation. In this era of climate change and global warming, we should know the importance of conserving our environment and biodiversity, and how they are helping us. Even in this developing phase, I think it is possible to increase biodiversity, improve human-nature interaction, and contribute to sustainable urban development by intentionally designing and maintaining these spaces. And it is important to protect hills, and natural wetlands and regulate forest covers, especially in the case of Guwahati as these are vital in balancing the ecology of the landscape.  

References:

1. Manoj V. Nair. (2006). Inside a city forest ñ The Natural History of Assam State Zoo Campus, Published by Assam State Zoo cum Botanical Garden, Guwahati, Assam.

2. Per Bolund &, Sven Hunhammar. (1999). Ecosystem services in urban areas. Elsevier.

3. Ulrich, R. S. (1984). View Through a Window May Influence Recovery from Surgery. Science, 224(4647), 420–421. https://doi.org/10.1126/science.6143402

About the Author :

Chandramika Nath is a wildlife researcher at Wildlife Genetics Division of Aaranyak. She is passionate about ecology, evolution and birdwatching. You can reach her at chandramika@aaranyak.org