Weeds yet to reach their full potential as invaders after centuries of change

November 11, 2014

Weeds in the UK are still evolving hundreds of years after their introduction and are unlikely to have yet reached their full potential as invaders, UNSW Australia scientists have discovered.

The study is the first to have tracked the physical evolution of introduced plant species from the beginning of their invasion to the present day, and was made possible by the centuries-old British tradition of storing plant specimens in herbaria.

The research team, led by Habacuc Flores-Moreno, looked at three common weeds - Oxford ragwort, winter speedwell and a willow herb - which were introduced to the UK as long as 220 years ago.

The results are published in the journal Biological Invasions.

"We found the weeds are getting better and better adapted to life in their new environment, so they will presumably become even more problematic invaders as time goes on," says team member, Professor Angela Moles, an ecologist in the UNSW School of Biological, Earth and Environmental Sciences.

"Britain has a very long and venerable tradition of collecting plants and storing them in herbaria, which is why we carried out our research there. But the findings are also relevant to Australia because we have weedy species here that are in the same biological families.

"Our evidence also shows that about 70 per cent of weeds in the state of New South Wales have undergone substantial changes since they were introduced," Professor Moles says.

Senecio squalidus, or Oxford ragwort, was introduced into the UK from Sicily and was first recorded in the wild in 1794. This yellow daisy has spread widely including along the railway lines of Britain. Australia has a wide range of other Senecio species present.

Veronica persica, or winter speedwell, is native to Eurasia and was first recorded in the UK in 1826. It is present in Australia. Epilobium ciliatum, a willow herb that is native to the Americas was first recorded in in the UK in 1891 and is also present in Australia.

Flores-Moreno, now at the University of Minnesota, sampled 505 specimens of the three weeds kept in herbaria from institutions including the Natural History Museum, Oxford University, Cambridge University and The Royal Botanic Gardens Kew.

Changes throughout the centuries in leaf shape, leaf area and plant height were measured - features which reflect how plants adapt to new water, nutrient and light conditions.

The Oxford ragwort underwent about a 20 per cent increase in both leaf area and plant height in the period since its introduction.

The leaves of the winter speedwell became rounder and 17 per cent smaller, while plant height increased by 14 per cent. And the willow herb showed a 50 per cent decrease in leaf area.

"The change in the species' traits seemed to happen in spurts. And all three invasive species showed evidence of change in at least one trait during the last 50 years," says Professor Moles.

"The capacity to keep changing long after being introduced could allow invasive species to spread to more and more diverse environments, leading to novel species interactions."
-end-
Paper: http://link.springer.com/article/10.1007/s10530-014-0789-8

Media Contacts:


Professor Angela Moles: +61 2 9385 8302, a.moles@unsw.edu.au

UNSW Science media officer: Deborah Smith: +612 9385 7307, +61 (0) 478 492 060, deborah.smith@unsw.edu.au

University of New South Wales

Related Invasive Species Articles from Brightsurf:

The invasive species that Europe needs to erradicate most urgently are identified
An international research team analyzed the risk impact and the effectiveness of possible erradication strategies for invasive species already in the region as well as those that have yet to arrive

Crayfish 'trapping' fails to control invasive species
Despite being championed by a host of celebrity chefs, crayfish 'trapping' is not helping to control invasive American signal crayfish, according to new research by UCL and King's College London.

Climate change is impacting the spread of invasive animal species
What factors influence the spread of invasive animal species in our oceans?

Invasive alien species may soon cause dramatic global biodiversity loss
An increase of 20 to 30 per cent of invasive non-native (alien) species would lead to dramatic future biodiversity loss worldwide.

Protected areas worldwide at risk of invasive species
Protected areas across the globe are effectively keeping invasive animals at bay, but the large majority of them are at risk of invasions, finds a involving UCL and led by the Chinese Academy of Science, in a study published in Nature Communications.

Charismatic invasive species have an easier time settling into new habitats
An international study, in which the University of Cordoba participated, assessed the influence of charisma in the handling of invasive species and concluded that the perception people have of them can hinder our control over these species and condition their spread

Invasive species with charisma have it easier
It's the outside that counts: Their charisma has an impact on the introduction and image of alien species and can even hinder their control.

Invasive species that threaten biodiversity on the Antarctic Peninsula are identified
Mediterranean mussels, seaweed and some species of land plants and invertebrates are among the 13 species that are most likely to damage the ecosystems on the Antarctic Peninsula.

Research networks can help BRICS countries combat invasive species
BRICS countries need more networks of researchers dedicated to invasion science if they wish to curb the spread of invasive species within and outside of their borders.

Look out, invasive species: The robots are coming
Researchers published the first experiments to gauge whether biomimetic robotic fish can induce fear-related changes in mosquitofish, aiming to discover whether the highly invasive species might be controlled without toxicants or trapping methods harmful to wildlife.

Read More: Invasive Species News and Invasive Species Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.