At the moment, the world is experiencing mass increase in human population growth. This is largely due to scientific (especially medicine) and technological advancement, where many sophisticated instruments and potent drugs are readily available to treat deadly diseases. In most regions across the world, particularly in Africa, people are moving from the rural to urban areas, majorly for economic opportunities. This phenomenon is presently causing urban sprawl, that is, the expansion of an urban area into areas of countryside that surround it. Throughout this article, I will use the term, urbanisation, to refer to the general demographic processes by which the world’s cities are expanding, which is in line with the general views of many scientific scholars. Meanwhile, biodiversity is the variety of life forms, including genetic, species and ecosystems. On one hand, conservation is the wise use and management of natural resources.
Today, the world population stand at 7.6 billion, and more than half of the population live in urban areas. It is predicted to reach more than 60 per cent by 2050. Generally, this is accompanied by development. While it is good from the economic and growth viewpoint, it is bad from biodiversity conservation point of view, especially when such developmental activities lack Environmental Impact Assessments (EIAs) and fail to account for biodiversity conservation.
Urban population in Nigeria has shown tremendous increase from 17.8 per cent in 1970 to 49.4 per cent in 2017. Currently, Nigeria is the most populous country in Africa, and globally the seventh with over 200 million. According to the Census Bureau of the United States, Nigeria’s population will reach 402 million by 2050, by 2100; the population could hit over 746 million. It will become the third most populated country in the world, superseding the United States.
Reported by the Nigeria National Bureau of Statistics, Kano State registered the highest population during the 2006 national population census with about 9,401,288 people. The expansion of socioeconomic activities in recent years, coupled with an increased flow of humans from rural areas and other states of the country led to rise in the human population of Kano. The population rose from 5, 810, 470 in 1991 to 9, 401, 288 in 2006. Nobody knows the exact population of the state after 13 years of general census. Consequently, biodiversity in Kano and Nigeria at large are under serious threat due to human population growth.
Urbanisation, which involves land use changes and transformation of natural areas, for residential, commercial and industrial activities have direct effects on biodiversity, through habitat loss and fragmentation, loss of inter-connectivity among species and their habitat; hence threatening their survival. Large construction/developmental activities such as mass housing and industrialisation, for instance, causes loss or decrease in natural vegetation, micro/macro habitats and biodiversity. Other effects of urbanisation on biodiversity include insufficient foraging and breeding sites as a result of paved areas, decrease in species richness (number of species found in an area), biotic homogenisation (replacement of native species by exotics), extinction of species (complete disappearance of plant or animal species), and noise pollution, which affects the ecology of many species.
In Kano, just two decades ago, there were many natural places designated as gardens and parks, which play a vital role in maintaining urban biodiversity. Presently, nearly all these parks have been lost and their remnants degraded due to urbanisation and poor management. Very clear examples of recent transformation of some of these natural areas are the two gardens along Maiduguri road, which have been replaced with a built mosque, school and filling station.
Another modification occurred along Zoo Road, where a large garden was transformed into a paediatric hospital. Furthermore, within the Government Reserved Areas (GRAs), there are a number of parks that have been converted into restaurants, and building apartment. Some gardens along Dan Agundi/ Bayero University, Kano (BUK) road have been neglected; hence they have been turned into cattle markets.
Instead of the state government to revive the dilapidated gardens and parks, as well as create new ones, considering the importance of these gardens, it recently allocated most of the Urban Green Spaces (UGSs) along BUK road and alike for building filling stations and other structures. Sadly, many of the allocated lands for green spaces around residential areas, especially estates have also been converted into houses or markets. In the last 20 years or more, I still remember seeing so many cattle egrets and speckled pigeon (barbela and hasbiya in Hausa language) around Zoo Road estates, especially the egret when the Fulani men graze their herds. In the present day space of Sahad Store and Zenith Bank still in Zoo Road, I will never forget the Shadikoko wetland area (an important ecosystem, mainly for aquatic plants and animals, as well as for water purification), where we used to go for swimming on weekends or Thursdays and Fridays.
Studies have it that urban gardens and parks not only provide a refuge to urban biodiversity, but also improve the general health and mental capacity of its inhabitants. Evidences have also proved that urban greening helps to check the rise in atmospheric temperature that causes global climate change, averting Urban Heat Island (UHI), where urban core would be warmer than the surrounding areas. Moreover, they help in water supply and wastewater treatment. Thus, in city like Kano and beyond, the need for urban greening should not be underestimated.
Elsewhere, UGSs are widely used for outdoor relaxation, recreation (e.g picnic), contact with nature, and help decreased respiratory illnesses through improving air quality, arising from carbon dioxide emissions from vehicles and generator engines. The benefits of parks and gardens are particularly appreciable by low-income people who cannot afford to go to distant recreational places within the country or abroad. Furthermore, gardens and parks within cities can provide a vital educational facility, where people can learn more about indigenous plants and animals. They especially provide opportunities where students and urban ecologists/conservationists can make comparative studies on the impacts of urbanisation on biodiversity.
Apart from these, vegetation and flower gardens in our backyards could provide shelter, breeding and foraging sites for many species. Natural (patchy) vegetation surrounding private, government or commercial areas enhance the incorporation of biodiversity in urban areas. In the case of Kano, typical examples are BUK old and new campuses, Emir’s palace, Audu Bako Zoological Garden (Kano Zoo), and Aminu Kano Teaching Hospital (AKTH). Obviously, it is impossible for someone to miss plant or animal species in these areas, with birds (by their calls and for those that pays attention to their present) and butterflies, as well as other insects being conspicuous. The emir’s garden, for instance, serves as the largest roost site for fruit bats, while Kano zoo provides the last refuge and breeding site for many animal species, particularly birds, snakes and insects.
Therefore, when created and properly managed, overall benefits of the UGSs are regarded as part of a livable and sustainable environment. The government, private institutions, urban planners and policy-makers are encouraged to take into account, biodiversity conservation in urban planning and development.
People and other stakeholders are also encouraged to plant more trees to enhance carbon sequestration. On the one hand, the Ministry of Environment should increase public awareness on the importance of urban greening. Undoubtedly, this will ensure that biodiversity is conserved, while providing important ecosystem services in human inhabited areas.
Ringim is of the Biological Sciences Department, Federal University, Dutse, P.M.B 7156, Dutse, Jigawa State.
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