top of page

September 2015 - British Science Festival - Alien Species

Soon just a glassful of water will reveal a list of all the plants and animals living in or near a river, lake or other body of water. 

This remarkable prediction was made during a session discussing alien species at the British Science Festival, held in Bradford from 7 to 10 September 2015, and chaired by Dr Helen Roy from the NERC Centre for Ecology & Hydrology.

An alien species is one found outside its usual range, and which has been introduced by human action.

10-12 new species arrive in the UK each year.

In total about 2000 alien species are known in the UK. Of these approx. 75% are plants, and 25% animals. Only 10-15% of these are harmful.

Animals are more liable to be harmful than plants, and water-living species are more likely to cause harm than those on dry land. Most cause no harm and some may be beneficial.

Harlequin Ladybird - HARMFUL 

 - imported from Asia to Europe for aphid control

- 44% decline in native 2 spot ladybird

- also eats soft fruit

Bryony Ladybird - BENIGN 

 - no harmful effects known

Buddleia - UNCERTAIN

 - beneficial to pollinating insects, offset by root damage to buildings          

The Non-native Species Secretariat (NNSS) has responsibility for helping to coordinate the approach to invasive non-native species in Great Britain. It has just published an updated action plan.

This involves:

         horizon scanning – predicting the next damaging species likely to reach Britain

         prevention – stopping the transport of alien species

         risk assessment

         rapid response – eradication if possible

         long term management

Current threats:

Asian Hornet

Poised on the French coast. A major predator of bees, with a powerful sting. The aim is to detect arrival in the UK and eradicate before establishes and spreads

Raccoon

Raccoons are kept as pets and in wildlife parks. They are “escape artists” and once out are able to hide and avoid recapture. In Germany in 1934 a small number were known to be living in the wild. They now number more than 100,000.

Quagga mussel

Carpet Sea Squirt

DNA as a sampling tool

At present species are usually assessed by researchers and volunteers spotting, sampling and recording. This is laborious and can miss species. DNA sequencing technology can provide a more complete view, and as technology advances may be able to map the biodiversity profile of an area, with estimates of abundance of the different species.

The technology has already been assessed in the detection of individual species, such as the Quagga Mussel in ballast water. It has also been used to evaluate the biodiversity of insect fauna in rain forest.

Most DNA sequencing relies on gene amplification, utilising the Polymerase Chain Reaction (PCR) to produce lots of copies of genes, which make detection easier. PCR “probes” designed to copy a particular gene of interest can be used to detect single species of interest.

The capacity of gene sequencers has increased enormously, accompanied by a fall in the size and cost of machines. Some new sequencing machines no longer require PCR. This makes studies more accurate in estimating the relative sizes of populations, and allows machines to become smaller.

Soon machines will become much more affordable, and of a size that could be used in the field. Researchers will be able to produce a bio-profile of an area, based on environmental DNA. 

The technique has already been used in the American Great Lakes to show invasion of alien fish from affected rivers despite the use of electrical barriers.

To interpret DNA results will require large catalogues of DNA signatures.

As part of this the National History Museum is leading work to record the DNA sequences of all 4230 aquatic species in the UK.

Public Involvement

The meeting also looked at ways to inform and involve the public. The example used was the check, clean, dry campaign, aimed at reducing spread of organisms.

Some species can live for weeks on wet equipment. Water users are asked to:

     check       equipment for organisms and leave any found where they were.

     clean        equipment ideally using hot water

     dry            out equipment

The advantage of this scheme is that it is cheap to introduce and implement, and no specialist knowledge is needed

Links www.nonnativespecies.org

References

Reliable, verifiable and efficient monitoring of biodiversity via metabarcoding.

Ecology Letters 16 (2013)

Ji Y, Ashton L, Pedley SM, Edwards DP, Tang Y, Nakamura A, Yu DW.

Rapid molecular detection of invasive species in ballast and harbor water by integrating environmental DNA and light transmission spectroscopy.

Environ Sci Technol. 7 (2015) :4113-21

Egan SP, Grey E, Olds B, Feder JL, Ruggiero ST, Tanner CE, Lodge DM

bottom of page