Tuesday, 1 March 1994

In the Chair: The President of the Academy

PRESIDENT: Ladies and gentlemen, as President of the Academy I am delighted to welcome you to this important occasion. We are to hear from Dr Thomas Lovejoy. He is a scientist of great distinction; he is Assistant Secretary for External Affairs of the Smithsonian, and Science Adviser to the US Secretary of the Interior.

He was described by the Washington Post as the public persona of the Smithsonian. The same journal said of him: `Tom has saved more species over dinner than most scientific papers ever published'. I invite him to address us on the subject `Biodiversity: The Most Fundamental Issue'.

The subject matter I intend to cover is certainly familiar to at least some of you, but I have assiduously avoided any Australian examples. So I hope at least some of the things I cite will be a little different and interesting to you.,

(Slide) Biological diversity is confusing to a lot of people because in fact it is very many things at the same time. If you look at it through evolutionary perspectives and think of it in terms of the radiation of evolutionary lines, like the Hawaiian honey creepers, biological diversity can also be seen as a characteristic of natural communities. For example, if you take a forest community in the north east of the United States, where here we have autumn weather colour-coding the different tree species, we are dealing with a biological community which characteristically has 10 or 15 species of trees at most. (Slide) If on the other hand you are looking at a biological community like an Amazonian rainforest, you are dealing with a community which characteristically has hundreds of tree species.

Biological diversity is also a way we look at the total variety of life on earth, whether we are looking at the 1.4 million described species of plants and animals and micro-organisms, or think of it in terms of units of life on earth, such as all the higher plants. Or we can think of it in terms of the way that living mass is distributed among different groups of organisms.

(Slide) We also think of it in the way biological diversity is distributed across the surface of the earth, and inevitably we think about the enormous concentration of species in the tropical forests which cluster around the equator on 7 per cent of the dryland surface of the earth, which may hold 50 per cent or more of all the species of plants and animals and micro-organisms with which we share this planet.

(Slide) We are used to gradients of biological diversity, such as illustrated here with species of ants, starting at the bottom of this slide at the southern tip of South America, Tierra del Fuego, where there are about two species of ants. As one progresses north and crosses into the tropics in the vicinity of Sao Paulo and when it has already got to a point where there are 200 species of ants, these kinds of gradients of biological diversity are another way that we think about the distribution of the variety of the organisms we share this planet with.

(Slide) Biological diversity of course is far from completely explored. We have tended to do a much better job of exploring our fellow vertebrates; indeed, it is fair to say that biological science and conservation suffer from a degree of vertebrate chauvinism. But also there is differential knowledge about flora and fauna as one goes to different parts of the earth. In Australia here there is still a great deal to be learned about the invertebrates, whereas in Great Britain I believe it is impossible for a bird to lay an egg without at least six people, three of whom are clerics, recording the fact!

When I started graduate school the general notion was that maybe 1.5 million species of plants and animals and other organisms had been described by science and that perhaps an equal number remained to be described by science, and the majority of those would be found in the tropics. Several years ago an entomologist at the Smithsonian Institute named Terry Irwin examined beetles in a few samples from the canopy of Peruvian rainforest and did some extrapolations which I am not here to defend, but which suggested that we had grossly under-estimated the variety of life on earth and that there might in fact be as many as 10 million species of plants and animals or indeed 30 million species of plants and animals.

My point is not to sit here and defend or criticise Terry's estimate but really to make the point that we have done such a poor job of exploring life on earth, allowing ourselves to be distracted by the fascinating advances in laboratory science. In molecular biology we have truly neglected that exploration, and in fact are unable to say within an order of magnitude how many species of living organisms we share the planet with.

(Slide) This refers to the tropical forest canopy which is one of the major unexplored areas. But there are plenty of others, including the soil right beneath our feet in almost any part of the earth and important parts of the marine realm.

Basically we still are not in a position of knowing the full basic dimensions of life on earth. Twenty years ago we did not know about the communities which life near the thermal rifts on the floor of the ocean; that there were entire communities down there which could exist on the primal energy of the earth, not depending on sunlight; organisms that could exist at temperatures in excess of the boiling point of water.

(Slide) We still find major new units of the variety of life, such as these strange little creatures, the lauracifera (?) which live in communities of sand grains.

I want to talk a little about how biological diversity intersects with our lives. I want to talk a little bit less about what we are doing to biological diversity because there really is not a lot of news about that. I want to talk not very much about what should be done about it, although we can get into that in discussion time. Rather, I really want to explore a variety of ways in which biological diversity relates to human existence and which we tend to ignore as we go about our daily lives.

The most obvious way in which biological diversity and biological resources relate to our lives is in terms of direct consumption of biological resources, whether it be the botanical species flavouring gin, or the many different species of plants which provide the basis for agriculture. But there are also other interesting ways in which fortunes of nations and individuals have been built on natural resources. One of the interesting examples of this relates to North America, and the fortune of the then richest man in America, John Jacob Astor. (Slide) If you go down into the bowels of Manhattan Island at the Astor Place subway station, you ultimately can see in the ornamentation the illustration of the beaver upon which he built his enormous fortune.

In more subtle ways we draw on biological diversity and biological resources at the genetic level. (Slide) This is a photograph of the second wild perennial species of corn discovered in Mexico in the 1970s, one which proves to be resistant to a number of the major virus diseases of corn, including one which took out about 10 to 20 per cent of the American corn crop one year in the early 1970s, and which is now being actively used by people in the hybrid corn business to breed resistance to that particular virus diseased for corn agriculture. Just this morning in a fascinating visit to the Plant Science Division at CSIRO I learned of two examples that are being pursued right here, one involving perennial relatives of soybean with resistance to the leaf rust disease which plagues soybean annual agriculture; and also wild relatives of cotton which are more tolerant of low temperatures than domestic cotton and are being actively examined right now for their potential to improve cotton agriculture and soybean agriculture.

(Slide) The vast majority of organisms are invertebrates and insects. To the average individual it comes as a great surprise that insects play useful roles, and particularly when one is looking at the kind of damage that insects can inflict on plants it becomes even harder to believe. But that is the basis for the great biochemical evolutionary warfare of all time between the grazing insect community and the plants on which they feed, with the plants evolving the capacity to produce biologically active secondary compounds which are noxious or poisonous to the insects and help them resist the grazing pressure. That in turn becomes the basis for exploration of the biochemical potential in all these plants for medicinal purposes. The best selling medicine of all time, aspirin, indeed derives from such a biochemical, indeed ethnobotanical cure going well back to thee time of Hippocrates who was prescribing infusions of willow bark as an analgesic.

(Slide) There is a great rush to try to harvest the knowledge of people like the Anamami (?) Indians in the Amazon Basin who have spent thousands of years exploring this potential and who have a great deal to teach us about what they have learned, if we can only give them a little more respect than did this Second World War aviators map which chose to divide the Indian tribes in the Amazon Basin into two kinds, hostile and unfriendly.

(Slide) One of the rapidly new developing ways in which biological diversity is becoming useful to human society is in the field known as bio-remediation, the use of living organisms with strange metabolisms and strange appetites to help us in environmental clean-up. The sediments of the Potomac River in Washington are hardly some of the nicest of pristine environments in the world, but the US Geological Survey studying the chemical composition of those sediments decided that they really had to look for biological activity to explain some of the iron concentrations, and in the process turned up a bacterium which is capable of reducing chlorofluorocarbons in anaerobic conditions. This field of micro-organisms with strange metabolisms and strange appetites is rapidly developing. There are still people who discount it as having tremendous potential, but I personally feel they are premature in discounting what these organisms will be able to contribute to human society, particularly with the whole notion of industrial ecology, of siting industries and clusters so that one industry can feed off the waste of another. As that industrial ecology practice develops it becomes useful to find a way to take, say, the heavy metals out of the waste stream of one industry in order for that waste to be used by the next. In any case it is a fascinating field because all these organisms that somehow have developed over evolutionary time have the capacity to do things that just a few years ago we would never have dreamed of.

My own personal view of the most significant way in which biological diversity contributes to human society relates back to science - biological diversity as an intellectual resource. By studying how individual organisms interact with one another we find surprising ways to build the life sciences, ways that sometimes do not seem surprising in retrospect but certainly were surprising at the time that the observations were first made, so that the mould which everybody appreciated as a flavouring for Roquefort cheese ultimately becomes the mould that gives rise to the notion of antibiotics.

(Slide) Or other chains of discovery such as derive from this bushmaster, a large viper from the Amazon Basin which sometimes grows to 8 or 9ft in length and which most people have very difficult times in ever developing an appreciation for, particularly when you explain to them that the venom of this viper causes the victims to have their blood pressure go to zero for ever.

People at the Butantin (?) Institute in Southern Brazil studying how that venom worked were able to uncover a system of regulation of blood pressure in ourselves, the angeotensin system, which had not been previously known. While one cannot take snake venom as a medicine because our digestive tract simply denatures the protein, the knowledge that that angeotensin system exists made it possible for pharmaceutical chemists to develop a molecule which indeed plays on that system. That is in fact generically known as captopril and is the preferred drug for hypertension in much of the industrialised world. So it is literally possible to say that millions of people are living longer and healthier lives because of the biology of some nasty snake in a faraway rainforest. These kinds of connections are very real and are rarely appreciated by people going about their daily lives.

Among a whole number of ways in which biological diversity contributes to human society through various ecological processes there are what people sometimes refer to as the public service functions of nature. While there is plenty of room for debate as to whether you need an entirely natural ecosystem to perform all these processes, none the less it is fair to say that human society has benefited from them without ever calculating them in any economic sense.

(Slide) One of the more interesting examples involves the Amazon River drainage, the world's largest river with 20 per cent of the world's river water. It is a vast region containing 3,000 species of fish, more than the entire North Atlantic. It is quite productive in terms of its fisheries. Indeed, 50 per cent of the animal protein eaten by people in the Amazon Basin is fish protein. But if you look at the water chemistry of the Amazon Basin it becomes very difficult to explain how the waters of the Amazon are able to support the kind of fishery productivity that they obviously and measurably do.

The answer lies in a fascinating bit of natural history which occurs during those months of the year when the Amazon and its tributaries rise several metres and flood the floodplain forests along their banks. During this time is possible for fishermen, for example, to canoe into the middle of the forest. It is also possible at that time for fishes to swim in the forest. There they feed on fruits, seeds and other organic matter that falls into the water. One has a major nutrient transfer taking place from the terrestrial ecosystem to the aquatic one. Something like three-quarters of the commercial fish species of the Amazon depend on this nutrient transfer during the high water months of the year. Some of these fish feed only at that time of year, and even piranha are known to go vegetarian at the particular high water months of the year. So you have a major contribution to fishery productivity in the Amazon, one that is quite threatened because the floodplains are an obvious target for agricultural development.

(Slide) Another example of ecological processes dependent on natural species and systems involves the Chesapeake Bay in eastern North America, certainly the largest estuary in the western hemisphere, if not the world, and one that is extraordinarily famous for its crabs, oysters and fishes, and a bay which has been declining in productivity over a number of years.

(Slide) This story is about the oyster itself, which does an extraordinary job, even today. The oyster population of Chesapeake Bay filters a volume of water equal to the entire bay about once a year. Prior to the decline in productivity in the bay, largely due to agricultural runoff, the oyster population filtered a volume of water equal to the entire Chesapeake Bay once a week. It is a very interesting way to think about a keystone species, and clearly had a great deal to do with water quality and productivity in the bay. Not long ago, when mentioning this, somebody told me that three years ago you could fly in a small aircraft across Chesapeake Bay and could literally pick out where the oyster beds were because the water was rough due to all the filtration activity.

On a larger geographic scale one of the interesting public services or ecological processes involves the Amazon Basin and the cycling of water within the basin. For as long as almost anybody can remember it has been dogma that the vegetation of a region is the product of its climate and does not affect its climate to any great degree. However, science conducted by Brazilian scientists in the past 20 years has demonstrated through three independent lines of evidence that half the rainfall in the Amazon Basin is generated internally. A general east to west movement of air across the basin starts off with a load of moisture from the Atlantic. (Slide) But if you look at what happens in a particular spot, as illustrated here, you will see that of the order of a half to three-quarters of the water that falls as rain is returned to the air mass and is again turned into rain farther towards the Andes.

The other lines of evidence look at isotope ratios and there is some quite sophisticated work. There is little question that in fact the presence of forests in the basin has a great deal to do with the amount of rainfall that takes place. And even the crudest of computer models suggest that if you were to totally remove forests from the Amazon Basin and replace it with pasture grasses, factoring in the evapotranspiration that could come from those grasses, you would have at least a 25 per cent drop in rainfall.

(Slide) Yet another way in which biological diversity contributes to human society is by being a set of very sensitive indicators to environmental change. Many of you are aware that a number of years ago the specialists in frogs from around the world began to realise that a number of populations were declining and a number of species were disappearing. The reasons for this have really not been sorted out yet, but it is some kind of signal of environmental change.

(Slide) One of the interesting ways of looking at it is in terms of biological diversity in a biological community. This shows a particular situation where pasture has been subjected to intense fertilisation over a period of years. You can see that from 1856 there were 49 species of plants in this pasture, and that by 1949 the number of species had declined to three.

(Slide) The reverse situation occurs when you remove stress from a biological community. If the species are still available to return to the community, you will get a recovery of the characteristic biological diversity of that particular system. In fact, in freshwater systems, in particular in North America, the numbers and kinds of species of diatoms have been used very successfully as a measure of stress and pollution in rivers and streams.

(Slide) Here is an example in the natural world of just this decline in species richness in a natural community as a consequence of stress. This is a valley on the coast of Sao Paulo in Brazil in the city of Cubatao, a major refinery and chemical factory area, subject to constant winds from the sea which bring all that pollution up against the surrounding mountainsides - to the extent that all the woody vegetation has been destroyed by the stress and there are even minor landslides occurring because of the reduction in vegetation diversity in that particular area.

(Slide) Just a word or two to remind us about the kinds of things which are affecting biological diversity around the planet. We often see it first in islands such as the Hawaiian islands because they are small and circumscribed areas. One of the things we have learned from people studying fossils and semi fossils on islands is that before the arrival of European settlers, such as Captain Cook getting an unhappy welcome to Hawaii, the previous indigenous peoples were already taking their toll of vertebrate species, largely for food purposes. So if you look at the history of bird species on Hawaiian islands, you will see that it has been a pretty dismal story. In modern times it had already been a dismal story prior to the arrival of Captain Cook. That was the selective way in which people had begun to reduce biological diversity, focusing on particular species for generally purposes of food, sometimes to remove a dangerous animal.

(Slide) I hardly need to say in Australia how important exotic species can be in reducing biological diversity. In Hawaii the latest flora list more exotic species than indigenous ones. All the known specimens of the little Stephen Island wren, which has long been extinct, were collected by a lighthouse keeper's cat.

(Slides) But by far and away the greatest threat at the moment is habitat destruction, whether in Southern California, where the last remaining coastal sedge scrub, the habitat of the Californian gnat catcher and dozens of other species characteristic of that vegetation, is being converted to suburbia, or in the central Amazon, where forest is being converted for shortlived cattle pasture, driven by subsidies and incentives.

(Slide) To remind us of the scale of all of this in the western Amazonian state of Rondonia, over a space of literally five years, starting in 1982 and going through 1987, 20 per cent of the tropical forest of the state of Rondonia vanished. Its disappearance was ultimately detected by satellite, leading clearly to one-way conversion of that landscape to very simple biological communities.

(Slide) Another very important way in which we are affecting biological diversity is not just in destruction of habitat but in the geometric patterns in which we do the destruction, fragmenting the habitat. You end up with patterns like this reduction in forest in the state of Sao Paulo, the Atlantic forest of Brazil, over a period of close to 500 years.

(Slide) It is not just a matter of tropical forest regions. Almost anywhere in the world you go - whether the tropics, the northern mid-west of the United States - you see reduction in habitat accompanied by fragmentation in the habitat.

(Slide) For a long time nobody ever thought that was particularly a problem until people began to look at islands and island bio-geography. One of the very first clues about that involved the Smithsonian's Tropical Research Station in Panama with its Barra Colorado island site in the middle of the Panama Canal, which had been followed rather continuously since it had become an island with the flooding of the canal in about 1920. At that point somewhere in excess of 200 species of birds were known to have been there; whereas 50 years later 45 of those were absent. It was determined in an initial analysis that a fair number of them probably had winked out on that island simply because the island was not big enough.

(Slide) This has led to a whole explosion of studies of habitat fragmentation, looking at habitat islands created by fragmentations such as here in southern Brazil. This involves the slow loss of species from these isolated fragments. One of the great problems is that when a protected area is set up, if it is really an isolated fragment, it may not in the end be able to protect many of the species which caused it to be set aside.

(Slide) One of the other ways in which biological diversity is being affected is through the destruction and burning of forests, particularly in the tropics. I mention this because in the end it will have an impact on biological diversity, biological diversity being destroyed and, through its contribution to rising CO2 levels in the atmosphere, ultimately having further impact on biological diversity.

(Slide) This is just to remind you of the scale of some of that tropical forest burning. This is again the western Amazonian state of Rondonia on one particular day in 1967 in which this weather satellite was able to detect 2,500 individual fires. The latest estimates I have seen of the contribution of forest burning to rising CO2 levels in the atmosphere put the number at roughly 1.7 billion tonnes of carbon as CO2 every year.

(Slide) This, I believe, will be the most famous graph of the 20th century. You all know it. It is the graph of CO2 levels in the atmosphere as measured on top of a volcano in Hawaii. The point I really want to make here is that when human-induced climate change takes place, or even natural climate change takes place, probably the least troublesome effect will be on agricultural systems, at least in those parts of the world where we have good extension systems and can substitute varieties of corn or whatever crop it may be.

Far more worrisome is the potential effect of climate change on biological diversity. (Slide) This is a sample listing from a book that Ron Peters and I did on biological diversity and climate change of the kinds of connections in nature which could be affected by change in climate. But what really worries me and a number of others is the way we are setting up biological diversity to be hit by climate change in a way which it never has been vulnerable to before. In the normal history of life on earth, biotic crises not excepted, species of plants and animals respond to climate change by moving up or down latitude, or up or down altitude. They track their required climatic conditions, often rescrambling themselves into completely new biological associations, but without necessarily much loss of biological diversity.

At the moment, however, and in the near future, if climate change - natural or unnatural - begins to take place, we are in a very different situation. Increasingly, our biological diversity is confined to small, isolated, protected areas in the middle of man-dominated landscapes. We have created a major obstacle course for plant and animal species which would otherwise be dispersing to track required climatic conditions.

There is not a lot to be done about that, except for two things. (Slide) The point I wish to make with this slide relates to the history of the variety of life on earth as measured by families of marine organisms. In the way that we are treating climate change and landscapes at present, we are setting ourselves up to add another great biotic crisis to the history of life on earth. What one can do about it, however, is the following two things.

The first is that we can look at ways to put natural connections back into our landscapes. (Slide) This illustrates a particular forestry plantation in the south of Brazil in which the plantation forest has been deliberately set up to fit within a matrix of natural forest. If we pay attention to restoration of riparian habitats, which has plenty of additional reason to be done by virtue of what it does for aquatic systems and fisheries, we can make a major contribution to restoring connections between what are increasingly isolated pockets of biological diversity.

The other thing is that we have to get under control the increasing contribution of greenhouse gases to the atmosphere. Somehow in the course of all this we also have to deal with human population growth, with roughly 100 million more people every year. We also have to deal with a lot of proximate causes as opposed to ultimate causes of environmental destruction by finding alternative livelihoods for the people whose daily efforts to support themselves are destructive of natural habitats.

I would like to return to this whole subject of how biological diversity connects with our lives and how very often we are unaware of those connections.

If you showed this slide to the average citizen of North America, he or she would say `Yes, that is Yellowstone National Park. It is a nice place to visit, the world's first national park, of which the United States should be very proud.' Those people would never dream of connecting it to the 1993 Nobel Prize for chemistry. And they would never dream of connecting it with the polymeries chain reaction which has become so fundamental in the past 10 years to molecular biology and biotechnology, and diagnostic and forensic medicine. This touches the reaction that enables one to multiply genetic material a billion times over in just a couple of hours. You no longer have to wait days for a diagnosis of the throat swab when you think you have a strep throat. Such a diagnosis can be obtained in a few hours, the condition can be treated sooner and the person concerned can be back in the work force sooner. It is a very important advance in diagnostic medicine, but probably incredibly more powerful in the way it contributes to the expansion of human knowledge about biological systems.

The chain reaction is a matter of doing that over and over again, the heat causing the two strands to separate the enzymes, causing them to replicate. This is only possible because of a heat resistant enzyme which was found in a bacterium in a Yellowstone hot spring - a little bacterium in the slime of the hot spring with the name of thermos aquaticus, literally a billion-dollar molecule. I think it makes a very strong case for how we are entering an age where biological diversity can contribute to human welfare, can generate wealth at the level of the molecule in ways which have never been possible before.

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