Wildlife and countryside charities have been left "bewildered and angry" by a 15% cut to environment funding by the Welsh Government.
Eight leading organisations have criticised the plans, set out in the draft budget for 2018-19.
They claimed an "apparent gap" was developing between ministers' pledges on environmental issues and actions.
The Welsh Government said the reduction reflected a transfer of funding to local government.
Environment and rural affairs is the smallest of the Welsh Government's seven departments in terms of the funding it receives, but its responsibilities are vast and varied.
They include administrating support payments for farmers, funding schemes to protect animal health from diseases like bovine TB and strategies to promote Welsh food and drink.
Conservation and management of Wales' environment and seas, preventing flooding and measures to encourage clean energy schemes and combat climate change are all part of its remit too.
Last week's draft budget allocated £243m to the department - a real terms cut of £43m or 15.27% compared to the previous year.
About £35m of that is because the money has been transferred from a central Welsh Government pot directly to councils as part of their block grants.
One analyst said although the funding was still there, it now had to compete with all the other priorities of local government.
However, the Welsh Government insisted most of the money would be used for delivering recycling targets and there was less risk it will be diverted elsewhere.
Rebecca Williams, director of CLA Cymru, which represents landowners, said the cut represented the largest percentage squeeze faced by any government department.
"The headline figure of a 15% reduction is concerning, particularly as this is a critical year for the rural economy. It really does raise questions about Welsh ministers' priorities and it doesn't send a very good message to rural Wales."
Farming union NFU Cymru said it was worried the department's ability to deal with Brexit would be "weakened".
The RSPB said it was "completely bewildered and angry", Plantlife Cymru said it was "extremely disappointed", while the Angling Trust branded the announcement "terrible news".
Others, such as the Woodland Trust and the Marine Conservation Society, questioned whether the Welsh Government would have sufficient resources to deliver its own legislation such as much-hailed Environment and Wellbeing of Future Generations Acts.
"There is an apparent gap between Welsh Government pledges on the environment and the reality of what's happening," Anne Meikle, head of WWF Cymru said.
But Guto Ifan of Cardiff University's Wales Governance Centre said: "The Welsh Government doesn't have much wiggle room.
"To a large degree it can't control how much it has to spend as that it laid down by the UK government in the form of a block grant for the next two years.
"We know there are increasing pressures on health and social services, and that means that if you protect those areas to meet those demands then the cuts do fall on other parts of the budget like the environment and economic development."
A Welsh Government spokesman said: "The reductions to the environment and rural affairs budget reflects the transfer of the £35m from the environment single revenue grant into the local government revenue support grant.
"Taking this into account, the reduction to the environment and rural affairs revenue budget in 2018-19 is 1.55%."