For centuries, cities have been filled with large population densities, and the physical extent of cities has grown slowly. This movement has been reversed over the last 3 decades. Today, urban areas around the globe are expanding on average twice as fast as their populations. I was fortunate enough to grow up in an area which had many green open spaces, even the house that we lived in overlooked a golf course. OK that’s not really a natural area but it felt like one because it had Springbuck ( Antidorcas marsupialis) and Tssebe (Damaliscus lunatus) antelope on it. I was also quiet fortunate in that one of the largest (if not the largest) game reserves was about 3 – 4 hours’ drive away from where I lived, called the Kruger National Park. Our family would often go there for holidays and is the most likely reason why I am so passionate about wildlife and conservation. However for many other people around the world they do not have the same opportunities that I had. Many people are unaware or don’t come into contact with much wildlife if they live in big cities or build up urban environments.
Although urban areas cover a relatively small portion of the earth’s surface, urban areas alter global environmental change. Urban expansion and associated land cover change aids habitat loss, threatens biodiversity, and results in the loss of terrestrial carbon stored in vegetation. Land-cover change could lead to the loss of up to 40% of the species in some of the most biologically diverse areas around the world.
Many species in amphibian, mammalian, and reptilian classes will be affected in varying degrees from urban expansion, species that are on either the Critically Endangered or Endangered Lists of the International Union for Conservation of Nature (IUCN). Africa and Europe are estimated to have the largest percentages of species to be affected by urban expansion, 30% and 33%, respectively. However, the Americas will have the highest amount of species affected by urban expansion, representing one quarter of all species in the region.
Preserve Important Local Biodiversity in an Urbanizing Environment
Because urban landscapes are increasingly large, they can be an important element of regional or global biodiversity. Many cities were originally established in riparian areas, ecological transition zones, and other area that are naturally species rich, which creates both problems and opportunities for conservation. For example, the Cape Floristic Kingdom in South Africa is being infringed upon by the enlarging urban front of Cape Town. Conservation efforts are underway in rural and urban areas in the region, including the establishment of the 900-ha Driftsands Nature Reserve, which is surrounded by the poor urban population of Cape Flats. A balance of the needs of nature and the human populations is important.
These issues are particularly important in regards to demographically, genetically, rare or threatened populations species which are put at risk by the expanding cities. In this regard, the reason for conservation implementation may be very species specific. For example, two rare Australian plant species, Conospermum undulatum and Macarthuria keigheryi, have large populations at the Perth airport, where ongoing research is identifying threats and appropriate management regimes. Likewise, a prairie remnant in the urban greenway system of Oklahoma City, United States, homes a potentially stable population of the Texas horned lizard (Phrynosoma cornutum), a species that is showing range-wide declines
Connect People with Nature and Provide Environmental Education
Urban areas offer an opportunity to teach environmental processes and conservation to large amounts of people, including those who lack the ability to travel to non-urban areas, where wildlife education has been found traditionally. The need for wildlife-centered education is growing. Children need hands on exposure with biodiversity to become passionate about its protection, but are spending less and less time outdoors and more time in front of a television or computer screen. Many conservation organizations acknowledge that outreach and education must play an important role in the long-term conservation efforts, but there is still too little emphasis on the urban landscape, where most people live and work, and on human demographic groups who do not regularly come into contact with natural ecosystems. Living in Cape Town for the past 7 years, I have been overwhelmed by the amount of effort and consciousness that the city has put into making people aware of their natural environment that they live in. There is just over 13 nature reserves in and around the city of Cape Town and just about all of them hold environmental education programmes for children. This is done to promote conservation in an urban environment, as well as ensuring the future protection of this highly biodiverse region. During my internship year working at one of these reserves (Table Bay Nature Reserve) http://www.capetown.gov.za/Family%20and%20home/See-all-city-facilities/Our-recreational-facilities/Nature%20reserves/Table%20Bay%20Nature%20Reserve I contributed and learnt a lot about urban conservation. There is also an organisation whose sole purpose and aim is environmental education, are called The Cape Town Environmental Education Trust (CTEET), http://cteet.co.za/they do holiday programmes, environmental awareness, environmental camps etc. Another example of environmental education is in North America.
In Austin, Texas (U.S.A.), people gather downtown to admire the evening emergence of 1.5 million Mexican free-tailed bats (Tadarida brasiliensis). The 100,000 annual human visitors are both a way for, and the product of, environmental education. Bat Conservation International hands out flyers and gives presentations about bat natural history and about the financial boon bats provide. Publicity has been so successful that Austin now has a bat statue, bat-watching riverboat tours, a yearly bat festival, and a hockey team with a bat mascot. This example shows the potential for the urban public to become informed and excited about nature on its front door step.
Beyond these aspects of basic environmental education, urban areas can also provide ways for more active involvement, such as citizen science, restoration ecology, and environmental monitoring. The need for environmental engagement is especially pronounced among those making decisions in our societies.
Provide Ecosystem Services
In an urban environment, even small green spaces can aid high impact ecosystem services, if they are well planned. For example, small wetlands can improve urban hydrology by absorbing contaminants or buffering against flooding. Vegetated rooftops can reduce the heating and cooling costs of buildings and slow runoff during storms, these are important benefits due to the heat-island effect. Green rooftops can have the added benefit of improving local biodiversity, not only for the primarily planted vegetation but also for beetles, spiders, birds, and other plants that may colonize the site. Some of the insects and birds might be especially important as pollinators. Another important ecosystem service is the scope for improving some aspects of air quality in urban areas. High amounts of urban vegetation can take in large amounts of carbon dioxide. Remarkably interesting is that urban trees may have a stronger effect on carbon budgets than trees outside cities. One shade tree in Los Angeles, California, can provide an overall carbon benefit the same as that of three to five forest trees, through its ability to take in carbon and moderate the heating and cooling budget of a building.
The City of Cape Town is renowned for its diverse plant species and high endemicity. The area is thus an important element of the Cape Floristic Region (CFR), one of the World’s Heritage Sites and biodiversity Hotspots. The CFR is a member of the Mediterranean Biome (recognized locally as the Fynbos Biome, recognized as one of the world’s most imperiled ecosystems and a global priority for conservation. The CFR has the second largest human population growth rate in the Mediterranean Biome, after Chile. Urbanization is primarily in the lowlands of the city. This high concentration of biodiversity within the urban context raises challenges for conservation. Thirteen plant species within the city are already globally extinct, making it one of the most sensitive areas in the world for plant extinction. Unless important steps are taken as many as 85 additional plant species may become globally extinct in the next 10 years.
Most landowners parallel to or inside the urban edge have development aspirations and may not be interested in conservation. In these areas, large amounts of funding will be required to purchase critical land in order to realize the Biodiversity Network. However landowners in rural areas may be interested in conserving natural remnants on their land by a formal stewardship agreement. This can be arranged with the provincial conservation authority, Cape Nature, in the form of a contract or biodiversity agreement. However, for properties adjacent to the Table Mountain National Park, a contract can be arranged between the landowner and SANParks.
The biodiversity of the natural areas surrounding the other urban areas in South Africa have not been studied as extensively as in Cape Town. While Cape Town chose to engage in organised conservation planning, other urban areas were only starting to document their biodiversity due to a growing awareness that detailed ecological data for planning and management of urban open spaces. The vegetation of natural areas surrounding cities and fragmented areas inside cities have been documented in Durban, KwaZulu-Natal, Potchefstroom, North-West Province, Bloemfontein, Free State, Johannesburg and Pretoria, Gauteng and Nelspruit, Mpumalanga. What sets apart these studies from the primary vegetation studies in Cape Town are the description of vegetation of altered and degraded areas as well. The city of Cape Town is at an advantage, according to scientists, in that they have a “dedicated biodiversity team” and they work hard between scientific knowledge on conservation and actions at ground level.
By 2030, 60% of all humanity is expected to live in urban areas. While there are uncertainties around the estimates of urban population growth, there is even greater uncertainty about where and how much urban expansion will take place in different parts of the world over the next several decades. How the future urban expansion will vary across the globe have important implications for protected areas and biodiversity. The relationship between urbanization and biodiversity is complex, the expansion of urban areas often degrades habitat configuration and connectivity with potentially harmful impacts on species dispersal. Urbanization is also a large threat to endemic species due to higher incidence of colonization by alien species. Furthermore, urban expansion will lead to increased habitat fragmentation, which may also lead to genetic or demographic isolation. In this case, it is not only the size of the urban areas but also their spatial configuration and variety in urban land use that matters for biodiversity. The future of urban land expansion will place significant pressures on biodiversity. (Lwasa, 2013)
The human population is growing at an enormous rate and more and more natural habitat will be lost. We need to start acting fast to find a balance, before all our natural beauty and resources are gone. I will leave you with a quote from Sir David Attenborough “Instead of controlling the environment for the benefit of the population. Perhaps it’s time to control the population to allow the survival of the environment”
So you may be thinking that this is a lot of depressing information! I wouldn’t blame you That is why I have made the sustainable life post, and by doing a couple of these suggestions you can reduce your carbon foot print http://exploringconservation.com/2018/06/16/the-sustainable-life/
Cilliers, S.S. & Siebert, S.J. 2012. Urban Ecology in Cape Town : South African Comparisons and Reflections. Ecology and Society :17(3).
Dearborn, D.C. & Kark, S. 2009. Motivations for Conserving Urban Biodiversity.Conservation Biology , 24(2): 432–440.
Ernstson, H., Leeuw, S.E. Van Der, Redman, C.L., Meffert, D.J., Davis, G., Alfsen, C., Elmqvist, T., Orleans, Á.N. & Town, Á.C. 2010. Urban Transitions : On Urban Resilience and Human-Dominated Ecosystems. AMBIO : 531–545.
Güneralp, B Seto, K.C. 2013. Futures of global urban expansion : uncertainties and implications for biodiversity conservation.Environmental Research Letteres:8.1.
Rebelo, A.G., Holmes, P.M., Dorse, C. & Wood, J. 2011. Impacts of urbanization in a biodiversity hotspot : Conservation challenges in Metropolitan Cape Town. South African Journal of Botany, 77(1): 20–35.
Seto, K.C., Güneralp, B. & Hutyra, L.R. 2012. Global forecasts of urban expansion to 2030 and direct impacts on biodiversity and carbon pools. PNAS: (109), 40 16083–16088.