Monday, 3 August 2015

Roe Deer and musings on Crassula, Pennington Flash

I cycled all around the flash tonight and even paid a brief visit to Lightshaw Hall Flash, but to no avail, the four juvenile black terns which had been present all morning had apparently gone. Still, I did get to see the family party of four roe deer from the Teal hide.

Of interest to me, the deer were eating New Zealand pygmyweed Crassula helmsii. This is an invasive alien species which can spread like wildfire from just the smallest leaf on a ducks foot and chokes up ponds making them unsuitable for many aquatic invertebrates such as dragonfly nymphs etc. It's almost impossible to remove from a pond, and has virtually taken over Teal scrape, covering almost all of the exposed mud.  

When I was volunteering at Martin Mere a few years back, one of the methods we tried to remove it was to completely drain parts of the reedbed and allow it to dry, then spray the Crassula. I'm not sure how successful this was. It's a bit drastic and obviouly wipes out everything else in the pond, and moreover since a single leaf is enough for it to return, I wonder if it's worth the effort, but I suppose you have to try something.Yesterday I watched a green sandpiper trying to battle its way through the stuff, which was waist high on the bird.

So it's at least being put to good use by the deer, and in fact it makes me wonder if it's now a vital piece of the ecological jigsaw which has allowed the deer to settle at the flash and raise young.

A sea of Crassula.

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