Friday, 16 December 2016

Lindisfarne National Nature Reserve Advent Calendar - Door number 16

Pirri-pirri bur
Alex Dodds our contract warden gives an update on her work over the winter. 
If you have ever finished a walk around the National Nature Reserve on Holy Island and ended up with little brown burs or seeds stuck to your clothing, then you will know how easily this plant can be spread through the natural environment.  Pirri-pirri bur (Acaena novae-zelandiae) is an invasive non-native plant species, and like all good invasive species has managed to find a niche, fit into it and exploit it perfectly.  The only problem with this is that the dune system of Lindisfarne NNR is not Pirri’s normal environment.  It was first recorded in the 1930s on the Northumberland Coast after having circumnavigated the globe all the way from Australasia, possibly by hitchhiking in imported wool being supplied to the local Tweed wool industry.
Pirri forms large, dense areas of vegetation which prevent native plants from establishing and causes artificial dune stabilisation robbing the area of open ground.   It has also been reported that the burs can become tangled in fledgling bird's feathers and prevent them from flying.
In order to be able to manage this invasive plant effectively, we must first know to what extent it covers the Reserve and how densely it grows within the sand dune system.  Throughout autumn we have carrying out the most extensive survey of the invasive Pirri-pirri bur on Holy Island ever.  Assessing the abundance of Pirri along transects covering the length and breadth of the Reserve enables us to accurately map it whilst also recording observations about the surrounding habitat. 

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