'Rule breaking' plants may be climate change survivors
A plantain (Plantago lanceolata) growing in its native habitat, Ireland. Photo: Dr Annabel Smith
Plants that break some ecological rules by adapting to new environments in unconventional ways could have a higher chance of surviving the impacts of climate change, according to from researchers at the University of Sydney, Trinity College Dublin and the University of Queensland.
, from the University of Sydneyâs , is one of the founding members of the international team that coordinated the global collaborative research.
âThe study is exciting as it is the first publication from the PlantPopNet team,â she said. âWe were able to attract researchers from around the world to study in their own backyard, at a low cost. Itâs a humble plant but it has the right mix of interesting biology to be a model for how plants might respond to altered environments.â
Lead author Dr Annabel Smith measures a Plantago during the annual census on Inis Oirr, Ireland.
, from UQâs , , from both UQâs School of Biological Sciences and Trinity College Dublin, Ireland, and PlantPopNet studied the humble plantain (Plantago lanceolata) in an attempt to see how it became one of the worldâs most successfully distributed plant species.
âWe hoped to find out how plants adapt to hotter, drier or more variable climates and whether there were factors that made them more likely to adapt or go extinct,â Dr Smith said. âThe plantain, a small plant native to Europe, has spread wildly across the globe â we needed to know why itâs been so incredibly successful.â
Professor Glenda Wardle
What makes Plantago special?
Professor Wardle said Plantago is a valuable pasture plant that provides food for butterflies and other wildlife. It is also used in herbal teas and herbal remedies by humans.
She said: âUnderstanding how plants contribute to ecosystems â farms, diversity along roadsides in the introduced range, and meadows in the native range â is more important as humans find more ways to live with nature, rather than remove it.â
"The ârules of ecologyâ simply didn't apply to this species," said Dr Smith.
Breaking the rules
Led by Dr Annabel Smith, the team set up 53 monitoring sites in 21 countries, including multiple sites in Australia. They tagged individual plants, tracked plant deaths and new seedlings, counted flowers and seeds and looked at DNA to see how many individual plants have historically been introduced outside Europe.
What they discovered went against existing tenets of ecological science.
âWe were a bit shocked to find that the ârules of ecologyâ simply didn't apply to this species,â Dr Smith said.
âEcologists use different theories to understand how nature works â developed and tested over decades with field research - these are the so-called ârulesâ.
One of these theories describes how genetic diversity or variation in genes embedded in DNA are produced by changes in population size.
Dr Smith said that this means small populations tend to have little genetic diversity, while large populations with many offspring, such as those with lots of seeds, have more genetic diversity.
âGenetic diversity sounds boring, but actually it's the raw material on which evolution acts; more genetic diversity means plants are better able to adapt to environmental changes, like climate change,â Dr Smith said.
âWe discovered that, in their native range, the environment determined their levels of genetic diversity. But, in new environments, these rule breakers were adapting better than most other plants.â
Measuring Plantago in Australia
Winning at evolution
The team found the plantainâs success was due to multiple introductions around the world, which forced genetic diversity throughout the wider species.
âThe DNA analyses showed us that ongoing introductions into Australia, New Zealand, North America, Japan and South Africa quickly prompted genetic diversity in these âexpatsâ, giving them a higher capacity for adaptation,â Dr Smith said.
âIn Europe plantains played by the rules, but by breaking it outside of Europe, it didn't matter what kind of environment they were living in, the plantains almost always had high genetic diversity and high adaptability.â
Dr Smith said the finding was fascinating for two crucial reasons.
âItâs important we now know that multiple introductions will mix genetic stock and make invasive plants more successful quite quickly â an important finding given some invasive species cause extinction to native plants and cost governments billions of dollars,â she said.
âAnd secondly, research on invasive plants can give us clues about how our native plants might adapt to climate change. Knowing what might make our plants more adaptable, more quickly, is essential.â
Plantago growing in Canberra. Photo: Dr Annabel Smith
Plantago facts
- wide distribution, native in Europe and introduced in Australia, New Zealand, North America
- well studied because of chemistry in leaves and interesting reproduction
- usually wind dispersed and also visited by insects
- common along roads and in lawns, but often over-looked
- important pasture plant
- used in herbal teas and herbal remedies
- host to vulnerable butterfly populations overseas
- kids play with the stems and âflick' the head of flowers away by twisting the stem
Declaration:Â Professor Glenda Wardle received partial funding from Australian Research Council for this project.