Every 5 June, World Environment Day gives us a platform to reflect on our environmental impact and question what we can be doing to tackle issues such as pollution, sustainability and global warming. For this year's World Environment Day, we sat down with Professor Angela Moles of UNSW Sydney to learn more about how our ecosystems respond to climate change. In collaboration with Inspiring Australia, Angela will be speaking at City Recital Hall on 16 June as part of our This Sounds Like Science series.
As a plant ecologist, how did you become interested in climate science?
Starting out I was really interested in finding out about the different ways that plants and animals grow and reproduce in different parts of the planet. In the deep past I did a study where I went to 75 different ecosystems around the world and measured how plants and animals were interacting in these different climatic conditions. Over the last few years, I've translated that into an interest in how the changing climate in one place is resulting in changes in the ways that things are growing and evolving.
We tend to think of evolution as something that occurs over centuries rather than decades. How is this mindset shifting?
There has been a lot of research over the last two or three decades that has shifted us away from that Darwinian concept of evolution being a geological timescale type process that happens over thousands of generations. It can actually happen really fast. We did a research project on one little daisy that grows on sand dunes in South Africa that was introduced to Australia in the 1930s. That little daisy has changed so much since it got to Australia that we're about to describe it as an entirely new species. It grows differently, it flowers at a different time. So even if they were growing side-by-side, the South African original population and the Australian population wouldn't even exchange pollen. They'd be completely separate. So in less than a hundred years, there's now this whole new species that doesn't belong anywhere else in the world, which is a little bit mind-blowing.
What are some effects of climate change that we can see on Australia's native species?
I had a student who was studying seeds that had been stored in seed banks for the last 40 to 50 years. She brought some of these old seeds back to life and germinated them, and compared them to new seeds collected from the same species in the same place at the same time of year. We grew them side by side, and we found all sorts of difference between the historic seeds and the modern ones and the seedlings that they made. Some, for instance, had increased their seed size by 80% and others had decreased by 80%. We can't tell exactly what's caused any one of those changes, but when we looked at how much the plants have changed over the last 40 years versus how much the climate has changed in the part of Australia that they're in, you could see a relationship. Where the climate has changed more, the plants have changed more and what the plants are responding to is not actually so much the average temperatures, but the extreme events we see in Australia, like heat waves and droughts.
Given that we're already seeing significant change so quickly, what does this mean for our ecosystems?
We can create these really complicated models that sort of give our best guess but it's really difficult to figure out exactly what's going to happen. But what we are going to see is a massive reshuffle of our ecosystem as species start interacting with different things and change the time at which they enact behavior. Plants may flower earlier, or insects may emerge after winter earlier, and what that means is that the interactions between plants and animals may sometimes miss. For instance, there's this orchid that is pollinated by bees, and the way it gets pollinated is that it mimics the rear end of a bumblebee and makes pheromones that make itself appear like a really sexy bee. The male bees hump the orchids and they get pollen on them, and that allows the plant to reproduce, and they go on to another plant and so on. It's great. But now the flowers are coming out earlier after winter, and so are the female bees, and it turns out that the male bees aren't completely stupid. If there are actual female bees around, they're not going to bother with the flowers, and that means the species isn't getting pollinated anymore and it's pretty bleak for them.
What are you hoping to impart on audiences with This Sounds Like Science?
What I want to do with this event is to spread a message of hope and show people how resilient some of our species can be and how they can change and adapt. They can change the timing at which they do things and they can change where they live. There are going to be huge changes to our ecosystems, but things are going to be able to adapt to this. It's just not going to look like it does now.
There are some things we can do, but it is important that we start making those changes. This is an issue that should speak to everybody, whether you're motivated by the economics of it, the opportunities for renewable energy in Australia, wanting to leave things for your children or just wanting to conserve Australia's amazing biodiversity. This is something that we know is happening. We know it's having effects, and no matter your reason for moving on it, there's some really good evidence that moving right now would be a very good idea.
Hear more from Professor Angela Moles at City Recital Hall on Wednesday 16 June for This Sounds Like Science: Ecosystems in a Warming World. Joined by musicians Marcus Chun, Regina Buenaventura and Quang Hong Luu, this free lunchtime series presents a unique blend of science and classical music.