Zapping Invasive Aliens

All in a day's work for a volunteer at my local RSPB reserve, Blacktoft Sands.

There are numerous examples of accidental or intentional introductions of non-native species. Thousands of them in fact. Most of them fail to survive, some just establish a tiny and stable population. A few do spectacularly well, and become a real nuisance, Japanese Knotweed, Himalayan Balsalm, Signal Crayfish, Zebra Mussels to name but a few.

Go to the top of the class if you have identified the plant in the photograph - it is Garden Angelica, Angelica archangelica, cultivated for centuries in herb gardens, and probably best known to those of us of more mature years for the long bright green candied stems used as decoration on iced cakes.

It was first noticed at Blacktoft about 10 years ago in the reedbeds, presumably having arrived via the river Ouse during a high tide. Finding conditions to its liking it has steadily increased and now dominates areas of the reedbed. The warden is therefore trying various strategies to control it, including spraying, removing seedheads, and mechanical means (which was my task today, digging it up in a test area). To add to the problems we cannot take any actions from mid-March to mid-August as this would disturb the breeding populations of march harriers, bitterns, bearded tits and reed warblers.

All suggestions gratefully received!