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2 Posts tagged with the botany tag

An Indian rust fungus has been released at several sites across England as a form of 'biocontrol' - using a natural enemy to control an invasive species, in this case the Himalayan balsam.


Introduced by Victorians as an ornamental plant, the Environment Agency now estimates that the Himalayan balsam occupies over 13% of river banks in England and Wales. It can reach over 3 metres in height and causes trouble by smothering vegetation, out-competing native plants and by adding to the risk of flooding by clogging waterways.


This week, the not-for-profit organisation CABI released the rust fungus in Berkshire, Cornwall and Middlesex after successful laboratory trials showed that it causes significant damage to Himalayan balsam but does not impact on native species.


The wet Bank Holiday weekend was a wash-out for some, but as Museum botanist Dr Mark Spencer explained, it was the perfect conditions for release: "the fungus does best in warm, wet conditions!"


Know your enemy


Dr Spencer has been advising on the project, which is headed by CABI with primary funding from Defra and the Environment Agency, and with contributions from Network Rail, the Scottish Government and Westcountry Rivers Trust.


Himalayan balsam.jpg

The Himalayan balsam, dominating the banks of the River Alt.

© Mike Pennington


The rust fungus, a natural enemy of the Himalayan balsam in its native lands in the foothills of the Himalayas, has been extensively tested as a natural control method. Conversely, using existing methods, the Environment Agency estimates it would cost up to £300 million to eradicate Himalayan balsam from the UK.


Selection of a suitable natural enemy and laboratory trials took eight years. If the rust is successful in the UK, Dr Spencer predicts it could resolve the problem of Himalayan balsam within a few years.

This is a really important step forward for the control of invasive species in Europe, I wholeheartedly support the decision to approve release. Project partners have already set up a monitoring programme to assess the spread of the fungus onto Himalayan balsam. If the fungus establishes itself at the trial sites there should be no need for additional releases, the fungus will spread naturally through the UK.

The licence to release the rust fungus is only the second of its kind ever issued in the UK, following the 2010 release of a specialist insect, Aphalara itadori, to control the plant Japanese knotweed.


Read more about invasive species in the UK:


A species of nightshade thought to be restricted to one area of Peru has been found in 17 other locations with the aid of habitat modelling.


Museum botanists Dr Tiina Särkinen (now at the Royal Botanic Garden Edinburgh) and Dr Sandra Knapp discovered the new species of nightshade, named this week as Solanum pseudoamericanum, in 2012 in the Andes. When they first found it, they thought this species only occurred in two river valleys in southern Peru. By using a method known as species distribution modelling, they predicted other regions of Peru where the plant might also be found, based on the environmental conditions at the original collection sites.



An example of the newly discovered Solanum pseudoamericanum, collected on 7 March 2012.

The flowers are on the left and the berries on the right.


A collecting field trip to northern Peru the following year uncovered the nightshade in 17 new locations predicted by the model. The success of the project proves the method of species distribution modelling can work in complex climatic regions such as the Andes, where there is an abundance of undiscovered species and data coverage is generally poor.


Mapping species


Species distribution modelling uses climatic data to help map the range of a new species, speeding up the process of cataloguing it worldwide and providing a way to accurately predict where that species might be found again.


The approach may be particularly useful when dealing with critically endangered species, where there is an urgent need to find and conserve remaining populations.


The work is part of a larger project to map the distribution patterns of all the endemic Solanaceae species in Peru, and to look for components of rarity; what sorts of things make plant species rare. With this information, researchers hope to be able to better describe, and then conserve, plant diversity in Peru.


Hidden diversity


Species distribution modelling has been used successfully for vertebrates before, but has not been widely tested in plants. Dr Knapp belives this may be because collecting plants is seen as reasonably straightforward, but this case study suggests that it is not always true.


Solanum pseudoamericanum was not originally collected because it looks a lot like a common weed. 'Collecting is extremely biased, and this raises the question of how we deal with absences,' Knapp said. The new species represents a category of 'hidden diversity', where new discoveries can be obscured by their physical similarity to known, common species.


Open data


The research, and all its associated geographical and specimen data, is published this week in the open-access journal PhytoKeys. By publishing the results and original specimens as open data, said Knapp, large specimen datasets can be combined by other researchers globally to produce more general analyses of diversity.