Are we building over biodiversity?

As our cities sprawl and real jungle makes way for the concrete kind, is there any place for nature? Mark Goddard is an ecologist from the University of Newcastle and he explained to Kat Arney why there's still hope for wild cities...

Mark - Well, it's a very important question. Basically, we understand biodiversity as the range of living things that are on the planet. It's often expressed as the number of species or what we call the richness of species that live within a certain place. It can even be a garden, it can be a city, or it can be a whole country for example.

Kat - When we think about the biodiversity in say, cities, big towns, small towns, villages, and then countryside areas, what do we see changing between cities and urban areas in terms of biodiversity compared to more rural and countryside areas?

Mark - Well typically, what happens is as we move along a gradient from a rural area to a city centre, more often than not, we see a decrease in the biodiversity especially when you move into a city centre, very dense urban area, everything is covered with concrete, there's no habitat for plants or animals. So we do see a significant decrease in biodiversity at this intense urbanization.

Kat - Is that across the board so we've got fewer different species of plants, fewer different species of insects, fewer different species of mammals?

Mark - Most different taxa will follow the same trend. But there's an important piece of work that I was involved in a couple of years ago. Actually, what we did, we looked at about a hundred cities across the world and we compiled the list of species which were found in those cities. It was quite surprising. There were 54 cities that we studied for birds and what we found was that actually, there was over 2,000 birds recorded living in 54 cities which is actually about 20 per cent of all known bird species so a striking amount. At the same time, there was over 15,000 plant species and that represents about 5 per cent of the total amount of plant diversity on the planet. So, it does seem that towns and cities can support important biodiversity.

Kat - Are there really kind of counterintuitive examples where maybe being an urban environment might actually be better for some types of wildlife?

Mark - Good question. So, another study that I was involved with recently called the Urban Pollinators project - involved looking at insect pollinators within 12 towns and cities across the UK and comparing the amount of different pollinator species within the town or the city, compared to nearby farmland and nature reserve. What we actually found was that although there were no significant differences between the numbers of pollinators overall, when we just looked at the bees on their own, we actually found there were more species of bees in the cities compared to farmlands. So, it seems that certainly for bees, cities can actually be very, very important habitats.

Kat - I live in London. I've lived in various parts of London. I've lived over in east London, right next to a nature reserve and had a sparrow hawk come down in my back garden one day - that was exciting. I've also lived in places where it's felt like there's no green spaces and no gardens or anything like that. Does it mean having areas for biodiversity in cities that they have to be big parks, big nature reserves?

Mark - This is an active area of research actually so it's an important question. Simply put, if you think about gardens for example, something I've studied myself quite a lot. In a typical city such as Leeds where I'm set in now, around about 30 per cent of Leeds is covered by garden. That's a huge amount and if you think of maybe an individual garden doesn't contribute too much, but when you think about how the whole network of gardens spreads across the city then they're extremely valuable, so yes. What you do in your garden can really make a difference.

Kat - If it's somewhere really tiny, what if you've only got a window box or a balcony?

Mark - Again, it all adds up. If you think about putting some pots out on your window sill, even if it's some herbs for the kitchen, they're fantastically good for bees. Again, just small spaces can really contribute when you think about them collectively as a whole.

Kat - And kind of briefly and very selfishly, what good does it do us as humans to have more nature and biodiversity in our cities, and to be thinking about it as we go forward?

Mark -   Research suggests that actually, having biodiversity around us and experiencing that biodiversity can positively affect our well-being although the relationship between is quite a complicated one. How well we can perceive biodiversity? We don't really know, but certainly it suggests that it can be very good for our health.

Kat - I suppose, as the world becomes more industrialised, more and more of us are living in cities, living in flats, living in the concrete jungle, perhaps it will help us not to forget that there is a natural world out there.

Mark - Absolutely. If you're thinking of the UK now, at least 80 per cent or probably 90 per cent of us live in towns and cities. So, we are becoming really increasingly disconnected from nature. So, we need to make sure that we have as much left within the city as possible. For most people, the only encounters they get with nature, it is in their own backyard or in their local park. So we need to do everything we can to support as much biodiversity as possible in those places so that they can have those positive benefits that we've been talking about.