Large sections of the wildlife haven have been cut back as part of annual maintenance carried out by environment chiefs.
But the work has angered Elizabeth Brown, of Messingham Road, who said she was incensed to find yet more of the beck's foliage had been removed.
She said: "Several weeks ago, massive areas of habitat were razored to the ground on the main walking side of the beck and at the weekend, while walking along the beck, I was yet again horrified to see that the bankside which had previously been left had also been butchered." She said the vegetation had been removed from the length of the bank.
"Why has this been done and especially at this time of year?" she said.
"The Beck is home to an assortment of different creatures and insects who lived in and fed on that habitat. It's home to kingfishers, possibly water voles, frogs, ducks and their young, moorhens, hedgehogs, bees, dragonflies, etc – they have lost their shelter, nests, homes and food."
Mrs Brown is concerned at the extent of the work and is keen to find out the reasoning behind it.
She said: "No soil has been removed off the sides as far as I am aware, so the excuse of possible flooding cannot be used as in scraping away some of the bank sides.
"Or is it just another misguided attempt at trying to tidy up nature?
"There are not many areas around here that are a haven for wildlife, so why on earth has this been done?"
A spokeswoman for the Environment Agency said the work was part of its usual maintenance to prevent flooding and conserve the water's fish.
She said: "It's an annual event which we have done for the past 20 to 30 years, removing the nettles off the beck.
"We have to take out the weeds and keep it clear to lower the flood risk and they also take up most of the oxygen in the water, so if we leave them the fish would suffocate.
"The team cut it back as much as they need to and habitats are something we bear in mind when we are doing it."