Staff at Gloucestershire Wildlife Trust say they have noticed an increase in antisocial behaviour at their sites during lockdown.
It comes as vandals burnt down a bird hide at Whelford Pools in the Cotswold Water Park.
The Whelford Pools reserve, between Fairford and Lechlade, used to be the site of two barren gravel pits, but is now a freshwater haven.
In spring, Great Crested Grebe can be seen dancing their courtship rituals across the water. It is also possible to spot otters, nightingales and bittern. And in winter, overwintering wildfowl are present in large numbers.
We've had problems with fires burning our wildflower meadows, we've had huge amounts of litter, we've had signs and gates destroyed. Loads more people are coming to our sites, and that's really good, but what we want to encourage people to do is respect the sites as well. >
Watch Ken Goodwin's report below:
The Trust says the hide will cost thousands of pounds to rebuild.