Adapt or die
We've been hearing about what we can do to protect biodiversity in an increasingly urbanised world but what can wildlife, and specifically animals, do for themselves? Professor Philip James is an ecologist from the University of Salford and he joined Kat Arney...
Philip - Well cities in general, they differ from the rural areas in a number of ways. Compared to rural areas, urban areas which are - we can think of as being landscapes dominated by concrete, brick, tarmac. They're usually warmer. They're usually full of more artificial noise. They have artificial lighting regimes, more chemical pollution, and they have relatively little vegetation. And what vegetation is there is often quite exotic. Furthermore, cities have different suites of parasites and predators. And the food that the wildlife can gain tends to be richer in fats and proteins. So, all of these things come together to cause stress within the wildlife and you can see that in some of the physiological stress signs looking at blood composition for example in their stress hormones. It also means that there tends to be a selection towards certain types of animals - omnivores and frugivores (the fruit eaters) rather than insectivores and carnivores.
Kat - So, what are the options for animals when say, the landscape that they've been living in then suddenly a load of houses are plonked on it? What can they do?
Philip - Well in general terms, they have three options. They can either run away, they can adapt, or they can die. An animal which is able to move could walk or could fly. It could do that to get to a nearby habitat which is still providing what it needs in terms of food and somewhere to breed, somewhere to nest. But if an animal is not able to move for whatever reason, then it would eventually die out as a result of starvation or through some other cause - disease, poison, predation, unless it is able to adapt.
Kat - What are some examples of animals adapting? Obviously, I don't really want to think about them dying. What are the changes that happen?
Philip - Well, it's generally covered by an idea called plastic behaviour. Plastic behaviour is this idea that within a life cycle of a lifetime of any individual species, it can change something about its behaviour. It might be the way that it responds to artificial light or the way that it responds to sound.
Kat - Are there any particular examples of this happening?
Philip - If we think about birds and what they tend to do, if they're living in an urban environment, we tend to find that their song changes in one of three ways. They either sing louder and that is actually the most common thing that they do, or they change the frequency of their song. Typically, the notes, the sound of an urban area are fairly low pitched. And so, a bird can raise its tone up of that low pitch or it can change the time that it sings, the time of day, might sign earlier or later when it's quieter. If we think about the grey tit which is a common urban bird, it's been shown they've been noisy compared to quiet conditions, the grey tit song is shorter, faster, and at a higher pitch.
Kat - We are urbanising at quite an incredible pace. Certainly in London, I see more and more blocks coming up, there's more and more developments I know in the Cambridgeshire area, and many, many other places across the UK. Can animals actually keep up with this? Can they adapt at a fast enough speed?
Philip - Well, some can and some can't. Those that have got this plastic behaviour ability, those that change their behaviour rapidly enough, these are the ones that are able to survive within the urban areas. It might be that they change their food source. It might be that they change when they do things the time of day that they're active. It might be, as I've already described with the grey tit, the way that they sing. These changes in plastic behaviour can occur very, very quickly and they can change more than once within the lifetime of an individual bird or an individual mammal for that matter. So go back to the idea of the grey tit. It could adapt the way that it sings because of a particular environmental issue that it's coping with today. If that changed tomorrow, it would start to make that change, it would start to adapt again.
Kat - And very, very briefly in one sentence, does this mean that they're kind of going to be okay and we don't need to worry about the animals?
Philip - The ones that are able to adapt, they're going to be okay. What we find is that across the world, the fauna and flora of cities tends to becoming more the same. It's the species that you find in cities are more like those in another city that they are in the countryside, around those cities.