Countryside Survey captures 'greenhouse' Britain
18 November 2008
Species that thrive in wetter, warmer conditions, such as ivy, black bryony and hedge bindweed, are becoming more abundant across Britain, according to the Countryside Survey published today.
Scientists use sophisticated recording devices, or tablets, to collect data
The report's authors are quick to point out that it is too early to finger climate change as the culprit.
Lead author Dr Peter Carey from the Centre for Ecology & Hydrology says, "It almost looks like the real greenhouse effect."
But he adds that this is deceptive. Heavy management of the British countryside will dwarf any climate change signal for a long time.
Overall, Carey says the countryside has become less manicured.
"Thuggish species like nettles and brambles have become more prominent, at the expensive of smaller species."
Britain's top 12 most abundant plants
1. Rye grass
2. Yorkshire fog (grass)
3. False oat (grass)
4. Stinging nettle
6. Creeping bent (grass)
9. Common bent (grass)
10. Red fescue (grass)
12. Couch (grass)
The 2008 report, the fifth Countryside Survey since its inception in 1978, is the biggest and most comprehensive survey of Britain's countryside and its natural resources. It is based on nearly 600 one-kilometre-square field surveys backed up by a detailed map made up of satellite images.
The £10m survey examined changes in plant species, lowland agricultural grassland, hedgerows, woodlands, moorland, heathland, bogs, ponds and streams, as well as carbon stored in UK soil and climate impacts in the countryside.
While the team working on the report found some species prospering in the warmer, wetter weather, overall, they detected no change in plant distribution or abundance that could be attributed to climate change.
The report states that the effects of climate change are complicated by the weather during previous survey seasons. During the first two surveys, 1978 and 1990, the weather was drier than average, while 1998 was wetter than the norm. The spring and summer of 2007 were exceptionally wet in England and Wales.
1. Black bryony
2. Wood avens
4. Smooth hawk-beard
5. Prickly sow thistle
8. Bristly oxtongue
9. Black grass
10. Hedge bindweed
But the ecologists found other significant results. The number of plant species in Britain's most common habitats - fields, woods, heaths and moors - fell by eight per cent between 1978 and 2007, though no significant fall was seen between the 1998 and 2007 reports.
Between 1978 and 1998 agriculture in Britain intensified. Since 1998, intensification has halted and the government has introduced schemes to increase biodiversity. It seems these schemes are working.
This overall figure masks other trends. When the ecologists looked at habitats such as field boundaries, the sides of streams and road verges, which act as refuges for species surrounded by intensively farmed land, they found a 15 per cent decrease in species numbers compared to 1978. And, significantly, this decrease continued to 2007.
The greatest drop in species numbers - 17 per cent - was found in 2500 plots targeted by the Countryside Survey for their 'botanical interest'.
1. Broad-leaved willowherb
2. Oblong-leaved sundew
3. Marsh foxtail
4. Marsh valerian
5. Eared willow
6. Wild strawberry
7. Dioecious sedge
9. Water forget-me-not
10. Crested hair-grass
The report states, "The long-term decrease in plant species richness coincided with the decline in abundance of farmland birds and butterflies over the same period."
The survey also reports that 'non-native species now account for nearly two per cent of the vegetation cover of the British countryside.'
Linked to the wetter weather, perhaps, the most startling result is the dramatic increase in the number of ponds in Britain. The survey concludes there are now 49,000 more ponds than in 1998 - a pond is an area of water between one metre squared and two hectares. This sounds like a good news story for pond life but the ecologists also discovered that just eight per cent of Britain's 487,000 ponds are in good health.
"We've lost the quality of the ponds that were there," says Carey.
Surveyors at work in Scotland
Drop in acid
The surveyors discovered a marked drop in soil acidity between the 1978 and 2007 reports.
"The reduction in sulfur deposits [from the atmosphere] is the likely driver," says Carey. Since 1986, sulfur deposition from heavy industry and coal-fired power stations has nose-dived by 80 per cent following efforts to curb emissions.
Carbon store stable?
The team measured carbon content in soils and found no change since 1978. Soils store vast amounts of carbon and climate scientists have been concerned that these stores may start releasing carbon to the atmosphere as the climate warms.
So far, the survey finds no evidence for this, though these findings contradict research by the National Soils Inventory monitoring programme that reported a large decrease in soil carbon concentrations in the period 1978 to 2008.
Surveying moorland in Scotland
The team agree they now need to investigate why the results differ.
The wet weather and the foot and mouth outbreak created challenging conditions for the 80-strong team of scientists working on the project.
"It took longer than we planned," says Carey. "And, because of the foot and mouth outbreak, we were shut out of some areas and had to return later."
The report was commissioned by the Department for Environment, Food & Rural Affairs (Defra) and NERC and will be used by government agencies to review and develop policies.