By Amy Munro-Faure
People love nature, or at least many people seem to be saying they love nature if the international sales of programmes like David Attenborough’s Living Planet are anything to go by. Tell us stories about animal behaviour (one of my favourites being the stealing behaviour of spotted bowerbirds) and we are fascinated and keen to draw playful comparisons with humans. Look at the rampant popularity of Youtube videos of animals doing silly things.
With this in mind, why are we currently believed to be on the verge of an extinction crisis, which could see many species wiped off the planet? In a recent WWF Living Planet Report, the global abundance of vertebrates seemed to have declined by 30%. Beyond looking at whether those species are important just because we think they’re pretty or interesting, many of these species that we may be losing also play hugely important roles on our planet. That air you’re breathing, yes, that oxygen that’s keeping you alive, well that oxygen almost definitely came out of a plant. There’s a very miniscule chance that it was synthesized in space and happened to aggregate around the earth when it formed and was part of the very small amount of oxygen around before plants got on top of that whole photosynthesis thing, but that’s unlikely. It was almost certainly made when a plant took some carbon dioxide, got it together with some water and a super cool enzyme called Rubisco and made oxygen and sugar.
There are plenty of other examples of the pretty great stuff that nature does for us. That aspirin you took last week for that pounding headache? We found that in a plant, originally. You live by a river, but your house has never been flooded? That’s probably largely due to trees upstream taking up the slack when extra water flows down the river. And this works at bigger scales too, ever thought about how plants have sex? A great deal of the time this works because insects pollinate plants, transferring pollen from the male part to the female part of the flower. By doing this, insects (and some birds) are responsible for ensuring the success of a vast proportion of the global harvest. Without them we literally would starve.
And it’s not just about plants and animals; the bacteria that do things like break down our waste products and keep our soils fertile are pretty important too. Collectively all of these things that nature does for us are known as ecosystem services. Revealingly in a recent paper it was calculated that the economic value of these services to us globally is similar to global GNP (although some scientists would argue that it’s worth a great deal more than its economic value!) (Balmford et al, 2002).
Going back to basics, we definitely need plants, no-one wants to suffocate. So then why are we cutting down our forests; surely such a valuable resource is one worth keeping? “Ah Ha!” I hear you say, but we don’t just need oxygen to stay alive. What about that pesky food that we need to eat? Surely it makes more sense to grow some plants that we can eat and that will also perform these wonderful ecosystem services for us? And frankly I think you’ve got a point. We do want to be able to feed the world, effective euthanasia via starvation for all members of the global population who can’t afford to eat doesn’t sound like fun to me. However, here we encounter a problem: if we completely cover the world in crops, we’re not likely to have many of our other ecosystem services left, not to mention all the animals that we rather love, such as pandas, three toed sloths OR these vulnerable frogs, aren’t they cute! So a balance needs to be found.
There are other problems to balance here as well; would we be better off farming extensively across the globe and integrating maintaining biodiversity into our farming procedures, or alternatively, should we farm smaller areas intensively and retain the rest of the land area as parks in which we localise our biodiversity? There is evidence for the benefits of both approaches. There is definitely some weight behind the idea of segregating our land use. It has been argued that urban lifestyles are more efficient than rural ones, with canalised distribution systems meaning that we make use of laws of scale. For example, it’s more efficient to transport all the milk in the country to a city where everyone lives and distribute it short distances there, than it is to collect the milk in the same way and then distribute it long distances to patches of countryside. Then we need to start thinking about who owns which land and what they think is a good idea to do with it. How can we motivate people to use their land more sustainably? Are people more likely to want to look after land if they have a future stake in its profitability (Hardin, 1968)?
In short, biodiversity loss and extinction of animals is a huge and probably underestimated problem in the world today, both in terms of losing attractive organisms that we like and the ecosystem services which facilitate our own survival. However, how we go about remedying this is an intractable problem and one which ultimately, I feel, probably comes down to the power of the masses to influence local land use patterns which could eventually produce net global change.
McRae L, Collen B, Deinet S, Hill P, Loh J, Baillie JEM, & Price V. (2012) The Living Planet Index in: Living Planet Report 2012 (ed. Almond R). WWF, Gland, Switzerland. http://wwf.panda.org/about_our_earth/all_publications/living_planet_report/
Balmford A, Bruner A, Cooper P, Costanza R, Farber S, Green RE, Jenkins M, Jefferiss P, Jessamy V, Madden J, Munro K, Myers N, Naeem S, Paavola J, Rayment M, Rosendo S, Roughgarden J, Trumper K, & Turner RK. (2002) Economic Reasons for Conserving Wild Nature. Science 297:950-953
Hardin G. (1968) The Tragedy of the Commons. Science 162:1243-1248