Wildlife needs more legal protection when Britain leaves the EU, MPs have said.
The Environmental Audit Committee is calling on the Government to bring forward new laws to ensure environmental protections are not weakened by Brexit.
The UK farming industry could face "significant risks" from a loss of subsidies and tariffs on exports, chairwoman Mary Creagh warned.
The committee wants ministers to introduce a new Environmental Protection Act to guard against the impact the UK's divorce from Brussels could have on the nation's wildlife and natural habitats.
Committee chairwoman Mary Creagh said: "Changes from Brexit could put our countryside, farming and wildlife at risk.
"UK farming faces significant risks - from a loss of subsidies and tariffs on farm exports, to increased competition from countries with weaker food, animal welfare and environmental standards.
"The Government must not trade away these key protections as we leave the EU. It should also give clarity over any future farm subsidies."
A new report by the committee examining what Brexit could mean for the UK's natural environment suggests that protections for wildlife and habitats could be adversely affected by the UK leaving the EU if the Government does not take action before or in the early stages of the Article 50 process.
The Government has set out plans for a "Great Repeal Bill" which would transpose EU law into UK law.
But the committee's report suggests simply copying EU law will not be sufficient in some areas and could lead to so-called "zombie legislation" which may no longer be updated while questions could arise over who is responsible for enforcement.
It suggests a new Environmental Protection Act should be passed before Brexit is formalised while the Government should set out how it will provide equivalent or better protection for the environment once the UK has left the bloc.
The report also highlights the "triple jeopardy" which farmers could face as a result of income changes from leaving the Common Agricultural Policy (CAP), potential new tariffs acting as barriers to trade and the possibility of increased competition with other large economies with lower environmental standards.
Meanwhile, the report suggests any new system of subsidies brought forward by the Government to replace CAP should strike a better balance between supporting agriculture and protecting the environment.
Stephanie Hilborne, the chief executive of The Wildlife Trusts, welcomed the report.
She said: "It shows that politicians from all parties see the need for positive action for our natural environment as we approach Brexit.
"Eighty per cent of our environmental laws are tied in with the EU so preserving and improving them during and after Brexit is critical." Ministers are expected to respond to the committee's report in full in due course.
A Government spokeswoman said: "The UK has a long history of wildlife and environmental protection and we are committed to safeguarding and improving these, securing the best deal for Britain as we leave the EU."