Concrete Jungle: Can Wildlife Adapt to City Living?

I think it’s safe to say we’re all a bit gutted about Planet Earth II finishing. The series finale showcased the brilliance of wildlife that have managed to adapt to city living in some of the most peculiar ways; Rhesus Macaques stealing fruit from street vendors, Spotted Hyenas pestering the butchers and catfish eating pigeons! Much of the episode painted a pretty picture of wildlife thriving in our cities, however the real story is far from that captured on Planet Earth II. With urban areas growing at an enormous rate, those animals that can’t adapt to the urban lifestyle are being pushed further back into shrinking fragments of land due to habitat loss. This loss in habitat is now the major cause of species extinctions (Fig. 1.). Although it seems a courageous few have braved the move from rural peace or urban chaos, are these the minority? And if so can we do more in our cities to encourage the more shy?

threats

Figure 1. The main threats to mammal biodiversity; habitat loss is by far the biggest threat. The same pattern is found in birds, amphibians and reptiles. Source: IUCN Red List

 

Greener Grass?

 Here in the UK foxes, birds, small mammals and badgers are a common sight in urban areas. These animals have become so well adapted to city living that their numbers are actually higher in cities than in rural areas1. In other areas of the world animals such as coyotes, racoons and even monkeys are commonplace in cities. What do most of these animals have in common? They are generalists, meaning that they can easily adapt to new environments by changing their behaviour and diets. For example badgers reduce their group and territory sizes to fit the smaller spaces that occur within cities and foxes change their diet and shelter choice to fit in with our waste disposal and gardens.

the-fox

Figure 2. ‘Nosy Neighbour’ photograph of a fox in the city. A Wildlife Photographer of the Year Award Finalist

Many bird species are also able to adapt urban living, as documented in Planet Earth II, Peregrine Falcons have become well established in New York City (Fig. 3.). What draws there birds of prey into the city is the abundance of food in the form of another urban adapter; the pigeon. For species like this the city appears to be the ideal settlement, however research has shown that although bird numbers may be high in the cities, they are often introduced species2. The problem with this is that it causes a decrease in biodiversity or homogenisation, because native animals are lost and replaced by the few introduced animals that can cope within cities. This is true of mammals as well and they are often the same few urban-adaptable animals across the world, leading to massive declines in biodiversity globally3.

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Figure 3. A still taken from BBC’s Planet Earth II, showing a Peregrine Falcon using a mast as a perch. Source: BBC iPlayer

Starlings are also found in many cities across the world (Fig. 4.), including the UK. These birds prefer the warmth provided by cities, which are often degrees warmer than rural areas, and can appear in huge numbers in urban areas. Despite this, research has shown that starlings who dwell within city limits suffer from reduced food availability, particularly at young age, when they are still being reared by their parents4. The diet of a starling consists mainly of insects and fruits, which are hard to come by in cities due to the lack of green space. This means that although we may observe these animals ‘adapting’ to the urban lifestyle, they are quite often suffering.

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Figure 4. A starling murmuration above the town of Aberystwyth. Source: Mail Online

Quite surprisingly, Kuhl’s Pipistrelle, have become common in Italian urban areas and have been found to have higher reproductive rates than those found in rural areas 5. This is by far the exception and not rule when it comes to bats in urban areas unfortunately, as they usually require forests to forage and rest. For example the Common Pipistrelle, which despite being found in urban areas, shows a negative response to this land use change.

So whilst there maybe a handful of species that seems to be thriving in our cities, many species we see in our cities are not capable of fully adapting to urban areas and therefore suffer. For every species that can crack it in the city, there are many more that can’t. These animals tend to be those highly specialised to their environment and unfortunately these are the animals that are already suffering due to other human-induced changes such as climate change. This means that the majority of species will suffer from urbanisation, which is not great news as its estimated that 70% of the worlds population, which is ever increasing, will be living in urban areas by 2050 (Fig. 5).

urban-growth

Figure 5. Estimated global urban growth (number of people living in cities) per hour

Maybe Next Time?

Failing to set up the right measures to protect species that will suffer from urbanisation may result in extinctions, which there’s no coming back from. We are in the position now to act before it becomes to late, but what can be done? Strategies already in place include the expansion and better guarding of protected areas against urbanisation, but another novel and challenging concept is the idea of making urban growth compatible with wildlife protection. This may include more green spaces in urban areas or the radical idea of ‘greening’ our buildings.As David Attenborough summarised in the finale of Planet Earth II “create the space and the animals will come”.

sky

Figure 6. Milan’s vertical forests on skyscrapers, Bosco Vertical, designed by Stefano Boeri Architetti. Source: smart-tek

This idea is one that has recently taken off, for example Italy have produced the first ‘vertical forest’ on a sky scraper (Fig. 6.), that not only benefits wildlife, but also the people as it helps reduce pollution in city and reduce the city noise. Singapore is also making strides, creating magnificent “solar-powered super trees” within their cities (Fig. 7.). The footage from Plant Earth showed how animals and human benefit from these structures, from an increase in food and shelter to recreation and aesthetic enhancement.

“Create the space

  and the animals

will come”

 

Green Space.png

Figure 7. A still taken from BBC’s Planet Earth II, showing the “solar-powered super trees” in Singapore’s Garden by the Bay. Source: BBC iPlayer

In a time of massive urban expansion, where we are pushing wildlife further and further back, is it really right that we ignore those courageous few that have adapted to the fast-paced life in the city? Or should we embrace them and learn from their ability to adapt to help us conserve those animals that lack the ability to adapt? Past declines and losses tell us that as we expand our cities we have to make provisions for the species that will suffer the most, or risk losing them forever.

 

References

  1. Bateman, P. W. & Fleming, P. A. Big city life: Carnivores in urban environments. J. Zool. 287, 1–23 (2012).
  2. Taylor, L., Taylor, C. & Davis, A. The impact of urbanisation on avian species: The inextricable link between people and birds. Urban Ecosyst. 16, 481–498 (2013).
  3. McKinney, M. L. Urbanization as a major cause of biotic homogenization. Biol. Conserv. 127, 247–260 (2006).
  4. Mennechez, G. & Clergeau, P. Effect of urbanisation on habitat generalists: starlings not so flexible? Acta Oecologica 30, 182–191 (2006).
  5. Ancillotto, L., Tomassini, A. & Russo, D. The fancy city life: Kuhl’s pipistrelle, Pipistrellus kuhlii, benefits from urbanisation. Wildl. Res. 42, 598–606 (2016).
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