Thursday, 16 September 2010

Kick-ass Perturbation

Radipole Lake, Little Egret.

Too many of our wetland nature reserves have become ‘tired-looking’ and ‘stale’ over the years. Ongoing same-old, same-old management has allowed stability in the habitats, usually with competitive species becoming dominant. In many habitats, a degree of disturbance can knock back the natural succession and open up opportunities for a greater variety of species to flourish again. This management disturbance may mimic natural ‘catastrophes’ such as wind, flood, ice or fire, which, in the longer term, are rarely as bad as they first seem. Such ‘Kick-ass Perturbation’ (as a colleague nicely puts it) can be highly beneficial as the habitat vigorously recovers. A good example is the recovery of the Strumpshaw fish population here.

Why don’t we do more of this KP? Well, lack of resources, perhaps a fear of change, and of complaints from visitors (incl. birders) who see the changes as damaging, are some of the reasons. The first time I instructed a large excavator to re-dig an old ditch on a SSSI, I couldn’t sleep for days I was so worried about what I had done. Within minutes the black scar was extending across the land and the ground shook as each bucketful of silt was lifted. One year later the site looked fantastic, ‘long-lost’ species had returned.

Anyway, getting to the point, and on to Radipole Lake, the latest stop on the reedbed tour. On a previous assessment back in 2006, I had identified the lack of lack of structure within the reedbeds and the lack of ditch maintenance as a key factor in the site’s decline. A plan was drawn up. That plan is now halfway through implementation and the initial results look excellent. Some great looking KP has been performed on the ditches and pools. The water now ‘boils’ with invertebrates and fish, and studies of the bats has shown increased use of these restored areas by feeding Daubenton’s and Noctules. Give it 2 years and I will expect booming Bitterns.
The major distraction during the visit was the number of Great Green Bush-crickets chirping away. Lodmoor looked good, with 3 Curlew Sandpiper, 2 Spot Reds, Ruff, Redstart, Wheatear and several Med Gulls.

Below - aerial views of Radipole before and after restoration of the ditch systems.

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