BIODIVERSITY matters hugely, writes Giles Archibald. It ensures our fresh water and our food.

It provides medicines and a source of carbon capture. It protects our landscapes and our coastlines.

As readers will know, we are losing our biodiversity at an historically rapid rate.

One of the causes of biodiversity loss is the introduction of species into a new environment.

Hedgehogs were introduced into South Uist in Scotland with disastrous results for ground nesting birds.

Rabbits were introduced in Australia, causing vast environmental damage.

Sadly, we have an invasive species right on our doorstep in South Cumbria.

Himalayan Balsam is a beautiful, yet dangerous, plant. It is alien to our landscape and is wreaking havoc on our natural vegetation.

It was originally introduced in this country almost 200 years ago as a pretty garden plant. But it escaped the gardens and is now all around us. There is a particularly bad infestation in the Rydal area and up through Grasmere. Seeds spread through river flow and, as a result, there are further infestations along our river banks.

Himalayan Balsam spreads fast and kills native plants by denying them nutrients and light.

It is dangerous not just because it destroys native plants but, in doing so, it leaves riverbanks bare and open to erosion when it dies back in the winter.

In the summer, you can see Himalayan Balsam throughout the district - on verges, by riverbanks, near pathways and by the sides of fields.

Fortunately, there are residents who are very concerned about the growth of this invasive species.

One councillor in the east of the district is renowned for pulling up Himalayan Balsam as exercise before breakfast every morning.

Other volunteers have been organised on a regular basis by the South Cumbria Rivers Trust (SCRT) and the Friends of the Lake District (FOLD).

They have done a fabulous job in arranging work parties over the summer to pull up this weed and destroy it.

We owe these volunteers a huge debt of gratitude and I will try to make sure that we support and enhance their extremely valuable work.

Indeed, we can all help, by either joining a work party next year - check out the SCRT and FOLD websites - or by following the example of the energetic councillor and pulling up a few plants ourselves.