Natural Resources Wales is asking people not to use fireworks or start bonfires, especially in places like nature reserves, as they can threaten the wildlife that lives there.
This follows a number of isolated incidents at several nature reserves across Wales recently.
Two bags of used and discarded fireworks were collected from the Dyfi Ynyslas nature reserve beach car park, near Aberystwyth.
Large amounts of bottles, cans and general rubbish have also been collected from other sites which are managed by Natural Resources Wales.
Ali Chedgy, Ceredigion Assistant Reserve Manager, Natural Resources Wales said:
“Nature reserves are fantastic places for people to enjoy and get closer to nature, but they also provide a home to the rich, diverse and valuable wildlife we have in Wales.
“We do ask all visitors to be considerate when they visit, and to be aware of the harmful effect that fireworks, fires, and leaving rubbish can have on the reserve.
As it is breeding season at the moment many animals have young or are on nests.
The noise from a firework can cause fear and stress to wild animals, forcing them to abandon their young or their nests.
The animals could also be injured if they come in to contact with a live firework.
Any rubbish left behind can also contain chemicals which, if eaten by animals, can cause distress or fatalities.
“Wildlife is an important part of our environment, our heritage and our culture here in Wales.
“Having a camp fire or letting off fireworks at a nature reserve might seem like fun but it is a risk to wildlife, the habitats they call home, and people living nearby.”
Some nature reserves across Wales are Special Sites of Scientific interest (SSSI) or Special Areas of Conservation (SAC), this means they are protected by law and any damage could be considered a criminal act.
If you see people lighting fires or setting off fireworks on a National Nature Reserve, please contact the Natural Resources Wales 24 hour incident hotline on 0800 807060.