The drought in parts of England could have a serious impact on wildlife, the Environment Agency has warned.
Conservation groups are worried that some wetlands, ponds and streams may dry out if there is not enough rain soon to make up for two dry winters.
Amphibians, aquatic insects and wading birds could be among those affected.
The agency said it would help groups that manage important wetland sites by being more flexible with the rules about taking water from rivers.
The latest assessment from the Environment Agency is that river flows have continued to fall at almost all of the key sites it monitors for drought, with 15 now classed as exceptionally low.
It said some parts of England had seen the driest 18 months since records began and warned that could have a serious impact on wildlife.
Drying streams and ponds will leave the young of amphibians, including frogs and newts, at risk - and prevent dragonflies and other aquatic insects from hatching.
Wading birds such lapwings and curlews could struggle to raise their chicks.
Water voles could be at greater risk from predators such as stoats and weasels as falling water levels leave their water-line burrows exposed.
There are also fears of forest fires and some trees, including beech and birch, dying off.
Environment Agency national conservation manager Alistair Driver said: "The amount of water that we use at home and in our businesses has a direct effect on the amount of water available in our rivers and for wildlife.
"We would urge all water users - including consumers, businesses and farmers - to use water wisely to help protect our valuable natural environment."
He added: "Nature is very resilient, but given that we are seeing early summer droughts like this happening more frequently, then we can expect to see the real impacts of climate change on the numbers and distribution of some of our more susceptible wildlife."
RSPB water policy officer Phil Burston said more needed to be done "to adapt to an increasingly unpredictable climate".
And Helen Perkins, of the Wildlife Trusts, added: "We urgently need to change the way we use water at home and across businesses. Saving water now could save wildlife from an absolute disaster."
Water companies across southern and eastern England have announced hosepipe bans amid drought conditions.