Australasian Science: Australia's authority on science since 1938

It’s not a jungle out there: rocking the ecological boat

If you were a pharmaceutical company searching for a natural plant compound to use as the basis for a new line of drugs, where would you begin?

Until recently, this question was a no-brainer. Everyone knows that tropical forests contain the widest diversity of species, all fighting for survival and defending themselves physically and chemically against being invaded or eaten. So the tropics should naturally provide the greatest selection of biologically active compounds.

“No,” says Angela Moles, a pioneering young ecologist from the University of New South Wales, who is transforming our understanding of the plant world and overturning some of the dogmas of ecology.

“Up in the Arctic tundra are 100-year-old willow trees that are just a few centimetres tall. They get to grow just a few leaves each year and they can’t afford to lose them. So, as you get closer to the poles the chemical warfare intensifies.”

Angela doesn’t just look at one or two plants or ecosystems. By searching the world’s scientific databases she can study thousands of species at the same time. But she’s not tied to the computer. In one study, she visited 75 different ecosystems, from African and Central American jungles to the tundras of Patagonia and Greenland. With an army of global collaborators she measures everything and then, back in Sydney, she crunches numbers and changes paradigms.

She has investigated issues such as why plant seeds vary from the size of a coconut to a speck of dust; how introduced plants evolve and “go native”; and how ecosystems adapt as the climate changes.

For her work in establishing Big Ecology—the study of ecology at a global level—Associate Professor Angela Moles has been awarded the 2013 Frank Fenner Prize for Life Scientist of the Year.

Much ecological theory was laid down in the 1960s and 70s, Angela says. At that time, people tended to study a species or ecosystem they thought typical or representative—and then they generalised. And statistical techniques and the computational ability to handle data were far less developed than today. “Ideas that seemed logical became widely accepted without rigorous testing.”

Angela and others are now putting such ecological theory to the test, and much of it has been found wanting. But it’s hard for some ecologists to lay these ideas to rest.

“We now have this concept of zombie ideas. These are theoretical ideas proven wrong by data, but they have been accepted for so long that people keep peddling them. So you now have these ‘undead’ ideas wandering around the world feasting on the brains of unwitting undergraduates.”

Her own ideas on ecology have been stimulated by a combination of curiosity and travel. “I became a scientist because I never grew out of being a child running around in the New Zealand bush. I like asking questions and figuring out answers.”

While she may have grown up in New Zealand, Angela was actually born in England and has lived in Australia for the past 17 years. “I consider myself an Australian with confused Commonwealth links.”

She started studying plants almost by accident. “I had two really inspiring plant ecology teachers at university. And I found that plants are easy to study. They’re good to work with, they don’t move around, there’s lots of data on them, and they generally look and smell beautiful—unlike fish.”

She moved into Big Ecology while doing her PhD in Professor Mark Westoby’s laboratory at Macquarie University in Sydney. “I got a grant from the university to go to a conference in Spain, and I used it to visit influential ecologists in my field around the world.” She ended up travelling to Panama, Hawaii, Sweden, England and California, in addition to Spain. “And I began to want to understand why the plants were so different in different parts of the world.”

That led to The World Herbivory Project, an epic proposal to the Australian Research Council to visit 75 ecosystems around the world in a two-year period and investigate the impact of the environment on plants at a global level. “I’m immensely grateful to the ARC who looked at this bold idea and said, ‘go for it’.”

It was a field study of unprecedented size and scope. Using modern communications—email, Skype, networks and conferences—such collaborations are now much easier to set up than in the past. “But you need a consistent protocol for acquiring all data, and to check that it is being adhered to everywhere. If you don’t, people in different regions tend to collect data in the same way they have always done—and that makes global comparisons difficult.”

And the collaborators must be given due recognition, a stake in the study. “I have now published with more than 250 other ecologists, which makes it difficult to find people who don’t work with me to review the theses of my students.”

But putting together global studies doesn’t have to rely solely on physical collaboration with others; it can also be done by going to scientific journals and reports, and extracting data. And that’s exactly what Angela did when studying the reasons for variation in seed size as part of her PhD.

The conventional explanation for seed size was a simple trade-off. At one extreme, plants formed a few large seeds and justified the amount of resources they expended, because the chances of each seed growing into a plant were increased by carrying a nutrient supply to tide it through bad times. Tiny seeds, on the other hand, were disposable—millions made, but only one or two expected to take root.

Using data from thousands of species, Angela showed the picture was far more complex than a blend of these two different strategies for exploiting the environment. Seed size actually depends on a whole suite of factors, among them the size, life cycle and physiology of the plant, and its evolutionary history. In the end, not only did Angela publish groundbreaking new work on seeds, she was left with the beginnings of a database of plant characteristics and environmental data on which she has been building ever since.

Now a Queen Elizabeth II Fellow at the Evolution and Ecology Research Centre of the University of New South Wales (UNSW), Angela’s database forms the basis of a huge study on how plants grow in the different latitudes and climates of the world, with respect to all sorts of characteristics such as height, leaf size, longevity and many others.

“We now have data on 450,000 species from 40,000 different sites,” Angela says. Using this data, for instance, she has been able to do the first serious analysis of how plant height varies with latitude. And as usual, she came up with some surprises.

Although plants that grow in the tropics are on average much taller than those growing at higher latitudes, the variation with latitude is not smooth. In fact, plant height drops suddenly at the edges of the tropics, suggesting a complete change in plant strategy moving into the temperate regions. And the sorts of measurements most often taken in ecological studies, such as average temperature and rainfall, are not actually that good for predicting plant height. Eventually, Angela hopes her emerging explanations for global patterns of plant distribution will help us predict the impact of and cope better with climate change.

Another topic in which she is interested is the phenomenon of introduced species. “When do they become part of the ‘native’ ecosystem? We’ve been working on the rapid evolution and speciation of introduced plants. We have already demonstrated that plants can make dramatic changes in traits when transplanted to a totally new environment. One of my students is investigating whether an introduced daisy is in the process of becoming a native Australian species. If she finds that it is, that’s going to upset some conservationists.”

For many years, Angela has been a reviewer for scientific journals, but her role in scientific communications has gone further than that. In 2005, she was asked to become editor of one of the world’s significant publications in her field, the Journal of Ecology. She did so for seven years. “I feel it is an important public duty to keep the machinery of science working. But I’ve also found it a great pleasure.” In fact, when she had to spend time at home after the birth of her second child, editing became her primary way of adding to her knowledge. “I learned a lot in a random sort of way.”

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