January 23, 2011 – Original Source: The Observer
Scientists warn of danger to Britain’s birds and fish as the ancient timetable of plant and animal life unravels.
Spring is sooner recognised by plants than by men, states the Chinese proverb – a point that has been backed by science. Researchers have found that the behaviour of plants and the animals that feed on them shows spring is arriving earlier every year. It also appears that this advance is accelerating, according to Dr Stephen Thackeray of the Centre for Ecology and Hydrology, in Lancaster.
“We have measured the date of the arrival of spring according to the behaviour of more than 700 species of British animals and plants – including life forms such as plankton on lakes – and we have found that, on average, spring arrived 11 days earlier in the middle of the past decade than it did in the middle of the 70s,” he says. “And the rate of change is getting greater.”
Some of the first signs of spring include the appearance of the yellow flowers of lesser celandines in woodlands. Similarly, oak trees come into leaf, black-headed gulls acquire distinctive chocolate-brown hoods, and rooks begin rebuilding their nests.
Thackeray adds that the speed of spring’s arrival has been monitored over many years using the timing of the appearance of plants, flowers and plankton. “Each year, a sequence of natural events unfolds,” he says. “Plant life becomes active, then herbivores that eat those plants, and finally the carnivores that eat the herbivores.”
The crucial point is that the appearances of plant life, herbivores and carnivores once dovetailed. However, they are responding to spring’s early arrival in different ways and at different rates, with the result that there is now a distinct danger that birds – which need to feed on particular species of insects – are hatching too late to do so. Similarly, juvenile fish that need to feed on water fleas may hatch too late, and could starve. “The timetable that controls the way spring unwinds is changing and we badly need to find out how that might affect Britain’s wildlife,” says Thackeray.
This is an enterprise in which the public can help, using tools on the website naturescalendar.org.uk, for example. According to a sighting registered there, a lesser celandine – which usually starts flowering in March – was spotted doing so on Friday last week.