A leading environmental organisation said it fears that decisions over Brexit will be taken by politicians who may not have Northern Ireland's best interests at heart.
Five months on from the Assembly elections the RSBP said it had concerns that Northern Ireland had no voice as the UK leaves the European Union - and that this could put nature here under threat.
The UK Government is about to begin converting decades of EU law into UK law and changing thousands of pieces of legislation to reflect Brexit.
Emily Hunter of RSPB NI said: "Essentially, the Withdrawal Bill will convert all existing EU law into UK law to ensure there is not a huge gap in UK legislation when we leave the EU in March 2019.
"This is a massive task and will require significant input and negotiation between Westminster and the Northern Ireland, Scottish and Welsh devolved administrations.
"A number of laws which provide protection for some of our most beautiful places - including Rathlin Island, as well as many of our threatened species such as hen harriers, redshanks or white-clawed crayfish - will need to be changed to reflect our exit from the EU.
"If there's no Executive in place, it's not clear who will have responsibility for making these changes or what opportunity people in Northern Ireland will have to scrutinise them.
"It may be that the Government in Westminster imposes changes that would mean less protection for nature in Northern Ireland."
RSPB NI said that up to now EU law has ensured minimum environmental standards are met across Europe. It said a similar framework will be needed for the UK to ensure that all four countries maintain high environmental standards and don't use Brexit as an opportunity to water down protection for nature.
"We believe this should be drawn up and agreed by all the devolved administrations working with the UK government, rather than being imposed centrally," added Ms Hunter.