Monthly Archives: July 2015

Which bee to keep?

Hairy-footed Flower Bee Anthophora plumipes ©Natural England/Allan Drewit

Hairy-footed Flower Bee
Anthophora plumipes
©Natural England/Allan Drewit

Bees often hit the headlines. Where birds once ruled supreme, the bee is the rising star of the conservation movement. The beneficent, busy bees make our world work for us by pollinating our crops and some provide us with honey.

During a recent visit to a firm in the City, I was scanning the surrounding buildings and picked out two bee hives set up on a ledge in the vertiginous face of a nearby building. Defra has a bee hive on its roof and our little friends busily exploit the nectar in the nearby London planes around Westminster. In spite of the sting in its tail, we have embraced the bee.

A lot of information passes by me on a daily basis but occasionally something jumps out at me. Recently, it was the juxtaposition of a scientific paper published in Nature Communications and a draft report that I had to review. The paper was about pollination with information about species loss from Britain.

The paper reported the remarkable discovery that about 80 per cent of crop pollination was provided by only two per cent of bee species. Meanwhile, the report listed all the rare species that might disappear from Britain in the not too distant future.

Without seemingly realising it, the authors of the scientific paper recapitulated a rule of nature which says that abundance distributions tend to follow something called power laws.  They occur in a huge diversity of situations: the number of words in languages, the number of people in relation to their wealth, and the energy used by animals and plants in relation to their body size. Power laws are all over the place.  They apply to the distribution of values of cars on the roads of Britain – you see very few expensive Ferraris, but lots of cheap hatchbacks. A chap called Preston wrote a seminal paper in 1962 showing that species abundances tended to follow these power laws. There are lots of rare species and just a few abundant species.

So, why did this connect in my mind with the messages I picked up about species loss? Well the dilemma the pollinator paper highlights is that most of the rare species listed in the report possibly facing extinction in Britain are likely to be functionless. On what basis could I advise about which species to keep – just the two per cent of bees that provide 80 per cent of pollination; surely not?

The science of ecology has known for a long time that species come and go. Studies by luminaries MacArthur and Wilson in the late 1960s suggested that species that inhabit islands do so. Since the world is made up of islands of a sort, whether in a sea of water or of cereal fields, their conclusions have broad implications for how to interpret species presence, absence and extinction. The species in any one place are a combination of the long standing residents who have adapted to the local environment and the opportunists.

The two per cent of bee species that provide 80 per cent of the pollination are likely to be such opportunists who have coped with the changing landscapes mainly brought about by agriculture. Those listed in the report as under threat of extinction from Britain, although not necessarily from elsewhere, are the losers in this game.

So does this new knowledge guide us towards a more informed kind of conservation? It defines the difference between two doctrines; one of species protection and another of functional importance. This is a spectrum and our individual values place us somewhere between its two extremes. I like species that are unusual and I also see a need to have productive, functional landscapes. Can the two be compatible?

The doctrine of function is played out most strongly through the lens of economics. A growing school of thought attempts to place a formal valuation on assets like species. By those criteria, the 98 per cent of species that contribute only 20 per cent of the pollination services have relatively little utility. Some environmental campaign groups quote the eye-watering large financial value placed on them by economists to support the case for conserving pollinators, but this has a different perspective if it applies to a few per cent of all species. Those who adhere to the doctrine of species protection will say that the same two per cent of important species today might not be the same two per cent needed in future. Maybe we need to protect them all just in case? The low-value 98 per cent of bees that don’t help much towards the pollination of our crops might have other roles we don’t yet see.

These views sit at either end of the spectrum. Of course we don’t want to lose rare species, but we may also need to take species utility into account. We could compromise by defining better ways to construct our landscapes but that will mean some hard choices. Whatever choices we make will favour some species over others and building a rational basis for those choices, as for example the current work on natural capital is tending to do, will be important. Science has a lot more to do to make the case for those we don’t want to lose and those we need to keep.

Could Miley Cyrus be more energy efficient?

One indicator, alluded to in the 30-75% of global energy used in metal extraction prediction, is something called ‘Energy Return on Investment’ (ERoI). One can, for example, use this to compare the efficiency of organic versus non-organic food production or the efficiency of different form of energy extraction. It works on the principles of the second law of thermodynamics, i.e. that every system – bacterium, person, animal, car, train, ship, organisation, ocean, planet, solar system etc – makes a loss whenever it processes energy.

This week the singer Miley Cyrus was named the Sexiest Vegetarian Celebrity of 2015 by animal rights campaign PETA. Putting moral or ethical beliefs about eating animals aside, our diet is one of the most significant impacts on our personal ERoI.

Like most mammals, I am about five per cent efficient, i.e. weight-for-weight, if I eat meat rather than the materials that were fed to cows, sheep, pig etc then, roughly speaking, I could have 20 meals of the materials fed to animals for one meal of the animal itself. Chickens are a little more efficient (birds do most things better than mammals except for how they breed and tend their young!) and fish are a lot more efficient because they are cold blooded. Shellfish are even more efficient again and they have the advantage in most cases that they eat stuff we cannot eat – sometimes we can’t even see what they eat. However, my EoRI is about 4:1 which means that I use about a quarter of the energy I eat in obtaining, chewing, swallowing and digesting my food.

If one takes the principles of ERoI and applies them to other things we take for granted then we start to see the difficulties. About 100 years ago the ERoI for oil was about 100:1. Today it is around 10:1 and for some forms of oil production it might be no more efficient than I am, i.e. 4:1. The worry is that, globally, we are using two to three barrels of oil for every new barrel found so the current ERoI for oil is less than 4:1 if one ignores the older and productive oil fields which will, of course, eventually run out.

Some analyses (1) reckon that an ERoI of roughly 5:1 is about the minimum needed for all our energy systems for civilization to survive in the long term. As we run out of energy and other materials we have to work harder and harder to obtain them and, eventually, we will put more energy in than we get benefit back. However, another side to this is the waste both in terms of carbon dioxide and other waste products that all this produces. We may be running low on fuel, but if the by-products are poisoning us then there is not much point in keeping on burning the fuel.

An interesting question, that perhaps one day I will try to answer, is whether this is also the ERoI of evolved natural systems, like natural ecosystems. Mammals like me are probably about as inefficient as any animal can get so I am atypical, but once one adds up all the other parts of the consumers within a natural ecosystem – the birds, insects, fish, microbes, arthropods etc – I suspect this might show that these ecosystems have an ERoI better than 5:1. A further interesting speculation is whether undisturbed ecosystems are even better, i.e. are they more efficient users of energy than disturbed ecosystems?

As an individual I am a ‘system’ that is not far off being about as inefficient as I can afford to be. This isn’t very inspiring, but if I add in the ecological inefficiency from eating meat, rather than eating the equivalent nutrition that we might otherwise choose to feed to animals, then I am definitely well below the boundary of inefficiency. Of course, when I add in all the costs of moving me around in the transport systems, the other materials I use for my clothes and all my other stuff then my efficiency drops off the scale.

Given her doubtless more resources hungry life, whether Miley’s vegetarian diet might make go some way to making her more efficient would be an interesting calculation!

  1. Hall, CAS, Balogh, S, Murphy, DJR (2009) What is the Minimum EROI that a Sustainable Society Must Have? Energies 2: 25-47, DOI: 10.3390/en20100025

 

Powering the Future

I had the pleasure of spending yesterday evening at the Royal Society Summer Exhibition. I’d recommend it to anybody if you want to dip in to what British science is about and what it can do for people. To a geek like me it was fascinating to hear first-hand from young scientists about the things which enthuse them. But it also has some deeper messages, especially for where I think government should be putting its money in the forthcoming spending review.

Prof Brian Cox visits Tokamak’s Faster Fusion exhibition stand at the Royal Society Summer Science Exhibition

Prof Brian Cox visits Tokamak’s Faster Fusion exhibition stand at the Royal Society Summer Science Exhibition

I learned more about the immune system in a 15 minute discussion with one of the young scientists than I had learned in a whole career working in biology (although I am not an immunologist). This conversation squeezed my intellectual juices to the extent that I felt sad that I couldn’t just give up all the complexity of making science work to develop better public policy and get in to the lab. It’s the laboratory, big-or small-scale, that is the engine house where new ideas emerge. It’s a rewarding experience for anybody to look at the immune system. It leaves me in wonder at the complexity of structure that can emerge from a process of natural selection. The immune system  is much more complex than anything that mere humans have managed to engineer.

Perhaps there is nothing more fundamental than the question ‘how did life evolve life?’. The really interesting problem is that for life to exist there needs to be a mechanism that induces self-replication of the molecules that code for proteins. We know that this sits within DNA, but DNA cannot replicate without a ribosome which is a small, high complex, organelle that exists within cells just to perform this function. So, the question then arises, “how did ribosomes come in to existence?” Whoever can answer this question is pretty close to answering the most fundamental question of all – how did we get here?

I also have to put in a strong plug for those exhibits that reflectedFlu Defra’s science and that were supported directly or indirectly by Defra’s funding. One wasabout influenza viruses. Many vertebrates (including humans) aresusceptible to infection by flu viruses and many of these viruses are able to infect more than one species. There are perhaps a couple of hundred variants of flu viruses depending on the form of two proteins on the surface of the virus, the ‘H’ and the ‘N’ proteins. Birds seem to be able to host almost all these variants and, thankfully, humans just a few. Some are almost benign in that they only cause very mild disease but others are deadly.

A problem is that different strains of each variant can cause different severity of disease. Knowing all this is vital to allow us to be able to design better control systems including understanding paths of infection and designing vaccines.  The Spanish flu pandemic of 1918 killed about 50 million people – more than were killed in the First World War. That was the H1N1 variety. Not to be too melodramatic, there are plausible scenarios where, in today’s world of mass travel (which leads to rapid transfer of viruses around the world) we could all succumb to influenza. We need to be on our guard!

Another fascinating Defra science project concerned the importance of meat. Some who have read my recent blogs will know that I am sceptical about meat as a source of nutrition when farmed through intensive rearing systems. However, what this exhibit shows is that through careful management of farming as a whole system and the use of pasture that cannot be used for direct human consumption, cattle producing beef is one of the most efficient ways of turning this in to food for people.

This is about matching, for example, the variety of grass that is grown to the digestive system of the breed of cattle that are eating that grass to maximise the transfer efficiency of grass to beef. In a sense, this is a very different kind of genetic engineering where one is being clever about matching the properties of the grass with the properties of the cattle. When one then starts to build this around ensuring that soils are sustained, rivers don’t become polluted with effluent and we minimise the amount of gas given off to the atmosphere as methane, ammonia or N2 one is starting to understand that the complexities of a farming system begin to match those of the immune system (see above) – and are just as fascinating!

However, for me, the highlight was the exhibit from Tokamak Energy. I learned that ‘tokamak’ is actually a Russian acronym, because the technology was invented in Russia. However, what excited me was that the company was using current technologies to build their machine – they felt they could do this without having to wait for any new basic discoveries to emerge – and they had a business model that was attracting investment. I wish them every success.

I have not been able to mention all the exhibits I saw all of which have their own wonderful stories to tell. However, I am struck by just how fundamental to the future and successes of humanity are all the examples I have given here. Many other exhibits also fell in to this category. From the fundamentals of how life forms through to the building of a machine that could power our future development, it’s a glorious accolade to British science.