The whole concept of ecosystem services has become much-chattered about in policy circles over the last decade even though the person on the Clapham omnibus would probably glaze over at the mention of it.
Ecosystem services are those useful things that are provided by the natural world that benefit us and that therefore have a value even if that value is often not taken into account in our financial transacations. At one extreme, the pleasure you get from seeing a blue tit come to your bird feeder is an ecosystem service but we are more often talking about things like carbon storage in peat bogs or ordinary soils, water being cleansed as it passes through a reedbed or flood alleviation provided by wetlands.
So a peat bog on top of a Welsh hill may be a poor place to practise agriculture, only good for a few sheep to graze, but it may be storing significant amounts of carbon (which, if released, would slightly worsen climate change all over the world) and it may act as a slow-release sponge thus reducing the flood risk for someone living in far-away Shrewsbury. The Welsh hill farmer gets paid for the sheep but gains no reward from the world for storing carbon, nor from the inhabitants of Shrewsbury for helping to keep their living rooms flood-free. And that means that if he (or she) were able to drain that peat bog they might increase their income from lamb sales even if it reduced those non-market, non-paid for, ecosystem services. You can see that the 'free' services that might be lost may be greater than the finacial gain to the sheep farmer but that won't 'count' in the way that individual economic decisions are made unless we put some sort of a value on the services. That might mean paying the hill farmer for the carbon benefits and flood-reduction benefits so that 'we' don't lose them.
If that peat bog is the home to Wales's last breeding dunlin then we could see that taking account of the carbon storage and water services would be a good way to save some wildlife too. If we valued the carbon and water then we don't need to persuade people to value the dunlin too - the dunlin get a free ride. So that's what makes this way of thinking attractive to nature conservationists, on a good day. Because, many natural habitats provide significant ecosystem services to humanity that we don't currently value properly we treat destroying nature as being without cost. If only we valued it better then we would have less destruction. It's absolutely true, and on a good day, well worth promoting.
On a bad day, this approach doesn't necessarily deliver quite what we would like. The Welsh hill farmer may find that he (or she) could drain the peatbog (bye, bye dunlin), plant it with conifers (replacing the carbon storage elements lost from the peat) and have a lake and a dam downstream to control water flows (thus replacing the flood mitigation services of the peat too). Stock the lake with fish and open the forest up to a car rally every year and you may be in clover even if not in peat.
I think that the ecosystem services approach is a good one - but best if I am in charge of it. In the wrong hands it can lead to almost as much ecological damage as not taking these services into account. Well, maybe that is overstating things, but I hope you can see that whilst there is great overlap between nature conservation and ecosystem service conservation, the overlap is not total.
Many of the species we love - and I use that word deliberately - are just the icing on the ecosystem services cake and therefore may not count for much even when ecosystem services do. You can save the rainforest without saving the tiger and the disappearance of the corncrake, and now the drastic reduction of many other farmland birds, insects and plants, is not prejudicing food production.
The ecosystem services weapon is a two-edged sword. In the right hands, valuing carbon may help to protect ancient woodlands, in the wrong hands it may lead to the planting of wildlife deserts of conifers in the wrong places.
Clearly, the right hands would be mine, or yours, or other right-thinking people's hands. But when we get into putting a price on things we are potentially walking into HM Treasury's territory. Just as focussing on money can lead to a poorer world, so in the wrong hands might focussing on the value of ecosystem services. Beware the blunt policy instrument.
Having said that, I see there being big potential advantages for nature if we value it more. So rather than shrink away, nature conservationists must get involved in the discussions. There are opportunities to save a bit more of the natural world around us by valuing it properly.
A love of the natural world demonstrates that a person is a cultured inhabitant of planet Earth.
Sooty - well said