How is Nature doing? Biodiversity, sustainability, and biomass

Last Friday, I posed the question under what definitions of Nature one can say that it is doing badly, and whether there were other ones under which it was doing fine. I was explicitly interested in how Nature is doing now relative to decades or longer periods past, though of course once one has a definition one can judge future trajectories with it too.

For those who want to cut to the chase, I personally would advocate moving towards a composite index of Nature on this planet, because no single goal would seem to capture what people really think when they talk about Nature. Such indices are already being developed for the oceans (see http://www.oceanhealthindex.org/). Yet, I could not find overall indices for world ‘Nature’, so it would seem there is a vacuum there for some organisation to fill. Presumably, as with the oceans, there will be moves under way to create such indices. I think they would be onto a winner.

There were many interesting reactions to the question of how to define Nature and whether it was hence in bad or good shape. One type of reaction was ‘how dare you pose the question’ which I presume is by people who have already decided on the ‘obvious’ answer.

A more serious and recurrent answer was ‘biodiversity’ and there is no doubt that that diversity has been rapidly reducing the last few centuries. Some openly said biodiversity should be the definition and it was also implicitly the answer by all those talking about the great extinctions of the past and the one we seem to be hurtling towards. And just to remind you in case you are wondering, I am not a climate change denialist though I am sceptical that anything but geo-engineering will halt climate change.

Still, I have always been ambivalent about thinking of Nature as ‘biodiversity’ and not just because of the obvious point that surely the state of ‘Nature’  should include some notion of volume and not just variance.

It is not hard to see the appeal of biodiversity as a measure of Nature: the more biodiversity, the more potential for yielding benefits to humanity. Also, the greater the biodiversity, the quicker the recovery would be from any temporary changes in the environment. Perhaps most importantly, the sheer love of variety would have one appreciate more diversity. So if we are to think of ‘Nature’ as a composite thing for which we would want some kind of index to measure its current state by, then biodiversity should surely be in that index. Commensurate with this, I am all in favour of breeding programs for endangered species and plant-seed banks as a means of preserving diversity.

The problem for an economist is that we can engineer biodiversity: if we were to truly take biodiversity as the state of Nature and we would like there to be more Nature, then the obvious question becomes ‘what type of diversity would you like to see’? Given that we have become much better at genetic engineering, the production of Nature would simply end up being a matter of setting enough labs to the task of creating more diversity.

As soon as one puts this kind of logical consequence to proponents of biodiversity, they invariably back-peddle and start to argue that human-made diversity somehow does not count as real. But that is just a cop-out. If one does not want to add to ‘Nature’ by paying for more man-made bio-diversity then clearly diversity is not the be-all and end-all of Nature but at most a part of it.

One can then up-scale the notion of diversity and redefine ‘Nature’ as being about a diversity and richness of habitats, under which definition it is again fairly clear it is not doing so well. The appeal of this alternative definition is much the same as that of simple biodiversity but the upgraded definition is now a bit more impervious to the obvious engineering riposte. It also is much closer to a notion of ‘sustainability’ in that greater habitat diversity more clearly involves a regenerative ability.

With habitat diversity we get closer to what a lot of conservation is about, with the protection of unusual habitats leading us to be careful of pristine environments. Again, it is a definition I would intuitively agree with, though once more it would be the case that if this is truly what we value then we should not be squeamish about setting our labs to work on the question of how to create (or re-create) whole habitats complete with appropriate fungi and bacteria. Of course, we are moving in this direction too, though I personally think we should be much more forthright in this. For the life of me, I can’t see why we should not welcome straightforward engineering in this realm.

A completely different conception of Nature is to define it solely in terms of the services it can provide us humans with, i.e. to define Nature in terms of its usage value. This was of course the definition used in the millennium report on this and by that definition, the state of Nature is ambiguous. For sure, there is no doubt that all kinds of habitats have reduced but they have in the main given way to other habitats, not wastelands (though there are some of those too). It would need some kind of composite index of Nature’s value to tell us whether it has reduced. If we simply think of those services as ‘food production’ then in fact Nature has grown in the last few decades, though perhaps the potential for more Nature has then declined.

Conrad at Troppo furthermore mentioned that if we think of Nature as being about sheer volume of living material or animal mass, then perhaps Nature would not be doing so badly either.

Sheer biomass has a lot of appeal as a measure of Nature. One can try and measure it; it has a democratic feel to it (every ounce of living material is worth the same); it includes us humans as well as any other animal; and one can quite easily weigh different types of biomass more heavily if one feels some things are more natural than others (surely the umpteenth tree is not worth as much as the first elephant!). It also has obvious positive connections to human service value and restorative powers so it partially captures those as well. So if I had to chose a single measure of Nature, I would probably go for biomass, and I was being clever about it I would transform biomass using a continuous CES love-of-variety utility model.

Still, even (transformed) biomass is not ideal because it fails to pick up the advantages of habitat diversity and its connection to usage value is too loose. What would thus be ideal is a Nature Index including biodiversity, habitat diversity, services to humans, and sheer biomass.

Yet, it is interesting to consider the question of whether biomass has in fact been reducing or increasing in the last few decades. Let’s consider that question on Wednesday.

 

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FDB
FDB
8 years ago

All organisms on earth are competing for a common pool of resources – the energy we get from the sun (including in its recycled forms), plus a little from volcanic activity.

Biodiversity of species can therefore be seen as analogous to an economic market, where firms compete, innovate, specialise and generalise to stake out their claim.

Where would this analogy lead, with your prediliction for biomass?

Well, Paul? Commie or fatcat monopolist rent-seeker? Which is it?

Given your crazy suggestion that humans create biodiversity in the lab to make up for the mass extinctions we’re causing (winner-picking? unintended consequences?), I’m going with commie.

More seriously, rapid environmental change will produce winners and losers among species. The losers die out or retreat to a pocket of habitat that still suits them (if they’re lucky and require only one type of habitat, unlike most marine species, many birds, and some land-dwellers). The winners proliferate and increase their range. It would be utterly unsurprising if this occurred without any hit to biomass. In fact, given that the cause is warmer temps, an increase would be expected at face value.

Including biomass in some multi-variant measure of the health of the biosphere is, therefore, not worth looking at unless you are prepared to privelege it as an end in itself.

In any case, and perhaps I’m rambling now… a more biodiverse ecosystem is more efficient at converting the sun’s energy to biomass than a less biodiverse one. This is, after all, the very reason for the existence of all the different species in it – for each, there was a niche available to make a living and they were the best at filling it.

In closing, I hope your great-great-grandchildren enjoy their phytoplankton sandwiches for breakfast, lunch and dinner.

PSC
PSC
8 years ago

Why the emphasis on biodiversity? – biodiversity is comparatively easy to measure, and you can measure it over millions of years. You’re right it’s not a perfect measure, but you’re just being silly when you bring up engineered diversity.

Other metrics, e.g. the complexity of the structure of food webs, are much harder to measure – they’re not really measurable historically – and in any event are correlated to biodiversity.

It’s analogous to using GDP as a measure for how well an economy is going. It’s widely accepted to have flaws. For instance we could easily engineer high GDP by forcing everyone to pay their spouses and children for domestic labor and rent. But given that no-one is going to do anything so daft purely to manipulate the metric, it works reasonably well.

conrad
conrad
8 years ago

Whilst I like diversity, and there are presumably benefits of it, if you weighted it strongly in a measure, you would probably be going against what most people actually want and therefore need quite a decent set of justifications for it (which I think there are). The reason for this is that it seems to me that a lot of our recent history has been about reducing diversity in almost everything, rather than increasing it, and people actually like this. For example, we try and eat the same varieties of food grown to the same standards, we keep the same set of pets, we play the same sports, we speak the same languages, we learn the same rules, and we even like the same animals in our zoos, despite their goals often being to protect diversity (make sure you are cute and fluffy and not a mollusc if you are endangered).

FDB
FDB
8 years ago
Reply to  conrad

Conrad, that is nuts. The only sense in which we “try to eat the same varieties of foods” is that we all want to eat all of them. Have you been to a supermarket lately? Did you go to one in the eighties? (That’s as far back as I can go, sorry) Compare and contrast.

There’s kangafuckingroo in the freezer at Costco in San Francisco. There’s edamame in the freezer of the milk bar on my street in Carlton.

Nobody wants to eat “biomass”. I know this even without needing to conduct a survey.

conrad
conrad
8 years ago
Reply to  FDB

Yes, I’ve been to supermarkets in many places of the world, and it appears they mainly sell the same stuff with a few local exceptions. With fruit, for example, you can feel lucky if you get two varieties of bananas and not one (c.f., the thousands that exist — this appears true of almost any other type of fruit/vegetable/grain/meat). Similarly, a quick search of resteraunt chains shows that the biggest is McDonalds followed by Subway, both of which you can buy exactly the same stuff from in almost any place on Earth.

If you really think most people like the almost infinite diversity of stuff that could be available, then feel free to tell me what significant thing there is where this occurs. Thinking of the things I’ve done today, I can safely say the following are pretty homogenous even though they need not be of (a) food (did you have a sandwich for lunch and weet-bix for breakfast?); (b) pets (do you have a dog/cat/rabbit); (c) transport (cars — they all look the same now); (d) text-books (they’re all formatted the same way now); (e) computer programs (do you use windows or windows?); (f) clothes (did you wear a suit to work, or jeans and a t-shirt? etc .

Sure there is a lot of possible variation in these things, but that’s not what most of the population uses or wants. If, for example, we really had lots of pets available to us that arn’t now (as is the case in the US), would we see lots of, say, Gambian rats sold (these are probably more fun than many other pets)? I don’t think so. People would still want cats and dogs.

So I’m yet to be convinced that people actually care about diversity, and many dislike some aspects of diversity (e.g., many harmless ethnic groups). People like homogeneity.

Back to the original question, basically it seems to me that when people say “diversity”, they mean “fluffy cute creatures”, versus real diversity. There are, for example, a large molluscs species that live in Australia, with many that are going to become extinct for one reason or another (many already have). Does anyone care about them? No, almost no-one cares, despite the fact that saving them would cost SFA (there are many other examples). You could just buy a few fish tanks and keep sustainable populations going. So the obvious conclusion to draw from this is that it isn’t diversity people care about with respect to nature, it’s a small number of creatures that happen to catch their imagination (e.g., pandas, tasmanian tigers, koalas).

FDB
FDB
8 years ago
Reply to  conrad

Your caricature of biodiversity might be appealing to a few people, but it isn’t the definition anyone on these threads is using, so I don’t know why you bring it up. It’s not what Paul meant, I’m sure.

Your suggestion that because a similar range of goods is found in supermarkets the world over we must be uninterested in diverse foods is simply bizzarre. The point is that this similar range of foods is an incredibly diverse one. Everyone with the means to pay uses their dollar to demand an ever more diverse list of ingredients – the world over. Without exception. How this can signify a dislike of diversity is baffling to me.

conrad
conrad
8 years ago
Reply to  conrad

FDB,

all I’m claiming is people don’t care about diversity much (read the last paragraph). If they did, why would every zoo have a giraffe (or hippo..), when a single one probably costs about as much to keep alive as, say, an endangered species of mollusc? When was the last time you saw a successful money raising campaign to save all of these less-loved species? When was the last time the government cared?

conrad
conrad
8 years ago
Reply to  conrad

I should also say that the extent people care about diversity is important, because many people intuitively argue that diversity is important (as can be seen from many other comments). However, if people don’t actually care about this then obviously a biomass measure is going to be weighted more heavily than a diversity one in terms of scoring nature.

conrad
conrad
8 years ago
Reply to  conrad

FDB,

If you want some more evidence that people really don’t care about diversity, this is a good story: http://www.guardian.co.uk/environment/2010/aug/08/pavlovsk-seed-bank-russia . I don’t know whether it has actually been bulldozed yet.

This of course is repeated in, for example, Melbourne, except then we’re trading off McMansions for habitat/diversity (and we know what wins), and not just destroying a seed bank.

Tel
Tel
8 years ago

So if I had to chose a single measure of Nature, I would probably go for biomass, and I was being clever about it I would transform biomass using a continuous CES love-of-variety utility model.

There’s massive bacterial biomass that is basically unmeasurable. I guess you could just measure biomass from a certain complexity up, or perhaps split the measure into bins (based on ??) which might make it more useful. I think the numbers should be historically increasing, and will continue to increase. For example, a modern field of wheat produces much more biomass than the scrub land that it replaced (but modern agriculture consumes oil, so it can’t continue in present form). I expect that gradually our ability to transport water over long distance will improve and the result will be more farmland.

There’s plenty of ecologists want to preserve desert as desert regardless of the low biomass and relative lack of commercial value. The argument being that if you pick any habitat you find unique species there, so we must conclude that all change is bad change (call them “conservative” if you like). I don’t think that’s a morally viable position but I can sort of see their point. Then again, you have people determined to preserve fringe language groups at all costs because the idea that people across the world can communicate is an anathema… same kind of mindset.

john r walker
john r walker(@annesanders)
8 years ago

” a modern field of wheat produces much more biomass than the scrub land that it replaced”

I think you are in a general sense wrong, pretty sure that the biomass of a scrub land/ forest is higher than a wheat field. (And ‘scrub land’ tends to be an indicator of poor fertility)

Tel
Tel
8 years ago
Reply to  john r walker

The wheat fields would also be infertile except that human farmers are in the business of carrying bags of nitrate and phosphate around the place.

wilful
wilful
8 years ago

As soon as one puts this kind of logical consequence to proponents of biodiversity, they invariably back-peddle and start to argue that human-made diversity somehow does not count as real. But that is just a cop-out. If one does not want to add to ‘Nature’ by paying for more man-made bio-diversity then clearly diversity is not the be-all and end-all of Nature but at most a part of it.

This is false. For example, Tim Flannery has suggested introducing Komodo dragons to Australia as a rough replica of the giant goannas that used to exist here.

One can then up-scale the notion of diversity and redefine ‘Nature’ as being about a diversity and richness of habitats, under which definition it is again fairly clear it is not doing so well. The appeal of this alternative definition is much the same as that of simple biodiversity but the upgraded definition is now a bit more impervious to the obvious engineering riposte. It also is much closer to a notion of ‘sustainability’ in that greater habitat diversity more clearly involves a regenerative ability.

Most definitions of biodiversity explicitly do include habitats and relationships, they are not simply counts of species.

Sheer biomass has a lot of appeal as a measure of Nature.

Not to most people. The oceans are turning into jellyfish and plankton (I exaggerate for effect). This is not what would appeal to anyone.

conrad
conrad
8 years ago

“This is not what would appeal to anyone.”

I think with a few assumptions biomass is fine if used sensibly (e.g., enough diversity and talking about things humans like to eat rather than where most biomass exists — e.g., in places of oceans we don’t go). Similar arguments are used for GDP as a measure — just because it isn’t perfect, it isn’t entirely useless.

For example, in most places of the world, the amount of fish people like to eat is down to very low levels (e.g., < 10%), yet most of the fish species that existed 100 years ago are still there. Based on a purely diversity argument, perhaps we therefore shouldn't worry (the species are still there after all) — but this isn't reality. The reality is that people don't get good fish catches anymore, and this is basically related to biomass (i.e., not enough fish). These things are important to people in the here and now. Now there may be exceptional cases where this doesn't happen even in waters where humans like to catch things (e.g., where species like squid populate regions to the full extent they can), but these are exceptional.

More interesting and hence arguable trade-offs exist on land where we cut down things like forests and replace them with things like wheat. However, even in these cases, biomass is important, since once could look at things like desertification where you have something versus almost nothing (which most people would agree is generally a bad thing), versus disputable arguments about what type of biomass is better (e.g., trees vs. wheat), ignoring slight differences in biomass that the different types of flora and fauna create.

john r walker
john r walker(@annesanders)
8 years ago
Reply to  conrad

“ignoring slight differences in biomass” they are not that slight.

After bacteria (which provably makes up most of life by mass) the next biggest slice of biomass is the worlds billions of large heavy woody things.