"It's this time of year when the weather starts warming up and frogs start breeding - but they haven't been breeding," says John Wilkinson, research and monitoring officer at the Amphibian and Reptile Conservation Trust (ARC). Amphibians   are just one of the groups of animals that nature observers fear may have problems reproducing this year, as groundwater levels are even lower now than in the infamously dry summer of 1976, according to the Department for Environment, Food and Rural Affairs (Defra). According to the UK's Centre for Hydrology and Ecology the average rainfall so far this winter has been the lowest since 1972. "If ponds dry up totally," says Mr. Wilkinson, "you could have lots of dead tadpoles." Drier and windier conditions could also make it more difficult for juvenile amphibians to survive their journeys between wet habitats. But Peter Brotherton, the biodiversity manager for Natural England, says that "drought is part of nature's cycle", and, at present, a lot of animals, plants and insects are still in hibernation. This means that the population picture is unclear. "However, when we get extreme events, we get animals dying," he says. "And what is worrying is that normally at this time of year we expect soil to be near saturation after winter." Charlie Kitchin, the RSPB's site manager of the Nene Washes in Cambridgeshire, says the 2,000-acre wetland and grassland area is now struggling following two winters with relatively little winter rain and no flooding. One species that could suffer, he says, is the black-tailed godwit . "There are only 50 breeding pairs in the country, and we have 40 of them, and everything is bone-dry," Mr Kitchin says. But one bad nesting season, he says, is "not the end of the world". "One of the features of flood plains is that they're _ anyway," he adds. "But if they fail to breed another year, the population is likely to dip again." According to the passage animals may have problems reproducing this year mainly due to   _  .
drought hibernation windier conditions extreme events