Food chain in disarray after changes in voles' boom-and-bust breeding cycle
Steve Connor is the Science Editor of The Independent and i. He has won many awards for his journalism, including five-times winner of the prestigious British science writers’ award; the David Perlman Award of the American Geophysical Union; four times highly commended as specialist journalist of the year in the UK Press Awards; UK health journalist of the year and a special merit award of the European School of Oncology for his investigations into the tobacco industry. He has a degree in zoology from the University of Oxford and has a special interest in genetics and medical science, human evolution and origins, climate change and the environment.
Thursday 04 April 2013
A small, brown rodent that is a staple source of food for a range of iconic species – from the barn owl to the Arctic fox – has undergone a dramatic and perplexing change in the way it breeds, scientist have found.
Normally, voles reproduced rapidly and over a three or four-year cycle they go through dramatic population booms, inevitably followed by a bust, which determines how many predators can live in a particular area.
However, scientists have discovered that throughout Europe, vole populations are no longer showing the dramatic boom-and-bust cycles that have characterised the species on which many other animals depend for survival.
A study of 12 vole populations from Scandinavia to southern France has found that over the past 30 or 40 years the natural dramatic spikes of the vole population have become much smaller for unknown reasons.
Instead of seeing up to 500 voles living in an area the size of a football pitch, scientists are recording a maximum of about 50, which falls down to just two or three when there is a natural drop in numbers as the cycle goes through a bust period, said Xavier Lambin, professor of ecology at Aberdeen University.
“Smaller herbivores like voles have population cycles which have a boom or bust dynamic – there used to be times of plenty of the animals and times of scarcity, as part of natural processes,” Professor Lambin said.
“However evidence has emerged in recent years of a greater uniformity in vole abundance between years. The outbreaks are no longer as marked. Like a weakening heart, the beat of the cycle is becoming fainter and this will profoundly affect many other species,” he said.
The fact that the same trend has occurred over a wide area of Europe and that it has occurred during the same period suggests a continent-wide cause. The scientists believe that climate may be playing a role as vole numbers during the winter months appear to have collapsed.
“We studied 12 populations of voles across Europe and found that while a faint population cycle remains, it’s now much dampened down. The change is most evident in spring, reflecting a worsening of conditions for voles over winter,” Professor Lambin said.
The study, published in the journal Nature, relied on detailed records of vole numbers going back to the 1970s from sites as varied as Kielder Forest in Northumberland, Rochefort in France and Umea in Sweden. The vast majority of the vole populations showed a dramatic decline in the boom-bust cycle, although two sites in Poland and the former East Germamy appeared to retain the original cycle.
“This change in one group of species at the bottom of the food chain is bad news for a diverse range of predators which relied on these years of plenty,” Professor Lambin said.
Voles, which live off plants, are at the base of the food chain and are considered a “keystone” species in ecology. The Arctic fox and barn owl depend on it heavily, as does the kestral and weasel, Professor Lambin said.
“The world will be a less exciting place without those spectacular fluctuations. It is a bit as if the Serengeti was to lose the huge disturbance caused by the large herds of wildebeest, zebra and antelopes migrating. Here such a change is taking place on our door step, in Europe,” he said.
Dolphins ‘deliberately get high’ on puffer fish nerve toxins by carefully chewing and passing them around
Iberian lynx cubs born in the wild bring hope for the world's most endangered feline species
AeroFarms: Work starts to build world's largest vertical urban farm in Newark
Morne Hardenberg: 'Great white sharks have a softer side most people never get to see'
Animal Extinction - the greatest threat to mankind
- 2 General Election 2015: 14-year-old boy asks Nick Clegg – 'can you kill Katie Hopkins?'
- 3 University student in court for allegedly covering housemates' food in window cleaner and spit
- 4 Ryan Gosling posts tribute to 'Ryan Gosling Won't Eat His Cereal' creator Ryan McHenry
In defence of liberal democracy
Over 50,000 families shipped out of London boroughs in the past three years due to welfare cuts and soaring rents
EU asylum policy is 'a direct threat to our civilisation', says Nigel Farage
The Rothschild Libel: Why has it taken 200 years for an anti-Semitic slur that emerged from the Battle of Waterloo to be dismissed?
General Election 2015: UK will be 'run for the wealthy and powerful' if Tories retain power, Labour warns
General election live: SNP suspends two members for disrupting Labour rally
£13676.46 - £16411.61 per annum + OTE: SThree: SThree Trainee Recruitment Cons...
£18000 - £22000 per annum + training: Ashdown Group: Business and Marketing Gr...
£20000 - £25000 per annum + Commission: SThree: Are you great at building rela...
£20000 - £22000 per annum + excellent benefits: Ashdown Group: Application Sup...