Penguins suffer as Antarctic krill declines

12 April 2011

By Mark Kinver
Science and environment reporter, BBC News

A number of penguin species found in western Antarctica are declining as a result of a fall in the availability of krill, a study has suggested.

Researchers, examining 30 years of data, said chinstrap and Adelie penguin numbers had been falling since 1986.

Warming waters, less sea-ice cover and more whale and seal numbers was cited as reducing the abundance of krill, the main food source for the penguins.

The findings appear in the Proceedings of the National Academy of Sciences.

Antarctic krill (Euphausia superba) is a shrimp-like creature that reach lengths of about 6cm (2in) and is considered to be one of the most abundant species on the planet, being found in densities of up to 30,000 creatures in a cubic-metre of seawater.


It is also one of the key species in the ecosystems in and around Antarctica, as it is the dominant prey of nearly all vertebrates in the region, including chinstrap and Adelie penguins.

Warming to change

In their paper, a US team of scientists from the National Oceanic and Atmospheric Administration (Noaa) and the Scripps Institution of Oceanography said a number of factors were combining to change the shape of the area's environment.

"The West Antarctic Peninsula (WAP) and adjacent Scotia Sea support abundant wildlife populations, many of which were nearly [wiped out] by humans," they wrote.

"This region is also among the fastest warming areas on the planet, with 5-6C increases in mean winter air temperatures and associated decreases in winter sea-ice cover."


They added that analysis of data gathered during 30 years of field studies, and recent penguin surveys, challenged a leading scientific idea, known as the "sea-ice hypothesis", about how the region's ecosystems was changing.

"(It) proposes that reductions in winter sea-ice have led directly to declines in 'ice-loving' species by decreasing their winter habitat, while populations of 'ice-avoiding' species have increased," they explained.
However, they said that their findings showed that since the mid 1980s there had been a decline in both ice-loving Adelies (Pygoscelis adeliae) and ice-avoiding chinstraps (Pygoscelis antarctica), with both populations falling by up to 50%.

As a result, the researchers favoured a "more robust" hypothesis that penguin population numbers were linked to changes in the abundance of their main food source, krill.

"Linking trends in penguin abundance with trends in krill biomass explains why populations of Adelie and chinstrap penguins increased after competitors (fur seals, baleen whales and some fish) were nearly extirpated in the 19th to mid-20th Centuries, and currently are decreasing in response to climate change," they wrote.

The team said that it was estimated that there was in the region of 150 million tonnes of krill for predators after the global hunting era depleted the world's whale population.

During this period, data shows that there was a five-fold increase in chinstrap and Adelie numbers at breeding sites from the 1930s to the 1970s, they reported.

"The large populations of Adelie and chinstrap penguins were not sustained for long, however, and are now declining precipitously."

They added that this was happening as rising temperatures and decreases in sea-ice was altering the physical conditions required to sustain large krill populations.

"We hypothesise that the amount of krill available to penguins has declined because of the increased competition from recovering whale and fur seal populations, and from bottom-up, climate-driven changes that have altered this ecosystem significantly during the past two to three decades."

The US researchers concluded that the penguin numbers and krill abundance were likely to fall further if the warming trend in the region continued.

They wrote: "These conditions are particularly critical for chinstrap penguins because this species breeds almost exclusively in the WAP and Scotia Sea, where they have sustained declines in excess of 50% throughout their breeding range."

http://www.bbc.co.uk/news/science-environment-13036795
(Via Dawn Holloway)

Experts DNA test England's adders to help halt decline

28 March 2011

Ecologists are running DNA tests on adders to check their genetic diversity amid fears the UK's only venomous snake is vanishing from the wild.

A recent study found that numbers of the reptile had declined since 2007.

Conservationists believe inbreeding in small, isolated populations could lead to a further decrease in numbers.

Experts from Natural England, the Zoological Society of London and Oxford University are taking swabs from the reptiles at 16 sites across England.

Ecologist Nigel Hand has already carried out health checks and collected DNA samples from five snakes at a Surrey Wildlife Trust site and 27 adders from an area in Norfolk.

Once captured, the reptiles are placed in a plastic tube to measure their length and protect the handler from their bite.

A swab is taken and they are marked before they are released back into the wild.

The DNA is then analysed to see whether larger or smaller populations have different levels of genetic variety.

Jim Foster, of Natural England, said: "With around a third of adder populations now restricted to isolated pockets of habitat, and with only a handful of snakes per sites, they could be especially vulnerable."

It is estimated that there are 1,000 populations of adder in the country with some groups made up of fewer than 10 adults.

Mr Foster said the tests would also help them understand why some adders had been found with abnormalities including malformed scales and missing eyes.

He added: "In the longer term, the last resort option is whether we should move animals between populations, artificially encouraging them to mix."

http://www.bbc.co.uk/news/uk-england-12878563

Bee decline already having dramatic effect on pollination of plants

Bee decline already having dramatic effect on pollination of plants

http://www.telegraph.co.uk/science/science-news/7980954/Bee-decline-already-having-dramatic-effect-on-pollination-of-plants.html


Bee decline already having dramatic effect on pollination of plants

A decline in bees and global warming are having a damaging effect on the
pollination of plants, new research claims.

By Richard Alleyne, Science Correspondent
Published: 5:30AM BST 06 Sep 2010

Researchers have found that pollination levels of some plants have dropped by up to 50 per cent in the last two decades. The "pollination deficit" could see a dramatic reduction in the yield from crops. The research, carried out in the Rocky Mountains, Colorado, is the first to show that the effect is real and serves as a "warning" to Britain which if anything has seen an even greater decline in bees and pollinators.

"This serves as a warning to other countries," said Professor James Thomson at the University of Toronto, who carried out the research. "For quite some time people have been suggesting that pollinators are in decline and that this could have an effect on pollination. "I believe that this is the first real demonstration that pollination levels
are getting worse. I believe it is a significant decline. I believe the pollination levels have dropped by as much as 50 per cent.

"Bee numbers may have declined at our research site, but we suspect that a climate-driven mismatch between the times when flowers open and when bees emerge from hibernation is a more important factor."

According to a previous study, England's bees are vanishing faster than anywhere else in Europe, with more than half of hives dying out over the last 20 years. Butterflies and other insects are also in decline due to habitat loss and climate change.

The situation is so serious that the government has launched a £10 million project to find out what is causing bees and other insects to disappear. It is estimated bees are responsible for one in three mouthfuls of our food,
and that insect pollinators contribute £440 million to the British economy through their role in fertilising crops.

For the latest study, Prof Thomson carried out a 17-year examination of the wild lily in the Rocky Mountains.

It is one of the longest-term studies of pollination ever done. It reveals a progressive decline in pollination over the years, with particularly noteworthy pollination deficits early in the season. The study will be published in Philosophical Transactions of the Royal Society B: Biological Sciences. Three times each year, Prof Thomson compared the fruiting rate of unmanipulated flowers to that of flowers that are supplementally pollinated by hand.

"Early in the year, when bumble bee queens are still hibernating, the fruiting rates are especially low," he says. "This is sobering because it suggests that pollination is vulnerable even in a relatively pristine environment that is free of pesticides and human disturbance but still subject to climate change." Prof Thomson began his long-term studies in the late 1980s after purchasing a remote plot of land and building a log cabin in the middle of a meadow full of glacier lilies.

Bee decline already having dramatic effect on pollination of plants

Bee decline already having dramatic effect on pollination of plants

http://www.telegraph.co.uk/science/science-news/7980954/Bee-decline-already-having-dramatic-effect-on-pollination-of-plants.html


Bee decline already having dramatic effect on pollination of plants

A decline in bees and global warming are having a damaging effect on the
pollination of plants, new research claims.

By Richard Alleyne, Science Correspondent
Published: 5:30AM BST 06 Sep 2010

Researchers have found that pollination levels of some plants have dropped by up to 50 per cent in the last two decades. The "pollination deficit" could see a dramatic reduction in the yield from crops. The research, carried out in the Rocky Mountains, Colorado, is the first to show that the effect is real and serves as a "warning" to Britain which if anything has seen an even greater decline in bees and pollinators.

"This serves as a warning to other countries," said Professor James Thomson at the University of Toronto, who carried out the research. "For quite some time people have been suggesting that pollinators are in decline and that this could have an effect on pollination. "I believe that this is the first real demonstration that pollination levels
are getting worse. I believe it is a significant decline. I believe the pollination levels have dropped by as much as 50 per cent.

"Bee numbers may have declined at our research site, but we suspect that a climate-driven mismatch between the times when flowers open and when bees emerge from hibernation is a more important factor."

According to a previous study, England's bees are vanishing faster than anywhere else in Europe, with more than half of hives dying out over the last 20 years. Butterflies and other insects are also in decline due to habitat loss and climate change.

The situation is so serious that the government has launched a £10 million project to find out what is causing bees and other insects to disappear. It is estimated bees are responsible for one in three mouthfuls of our food,
and that insect pollinators contribute £440 million to the British economy through their role in fertilising crops.

For the latest study, Prof Thomson carried out a 17-year examination of the wild lily in the Rocky Mountains.

It is one of the longest-term studies of pollination ever done. It reveals a progressive decline in pollination over the years, with particularly noteworthy pollination deficits early in the season. The study will be published in Philosophical Transactions of the Royal Society B: Biological Sciences. Three times each year, Prof Thomson compared the fruiting rate of unmanipulated flowers to that of flowers that are supplementally pollinated by hand.

"Early in the year, when bumble bee queens are still hibernating, the fruiting rates are especially low," he says. "This is sobering because it suggests that pollination is vulnerable even in a relatively pristine environment that is free of pesticides and human disturbance but still subject to climate change." Prof Thomson began his long-term studies in the late 1980s after purchasing a remote plot of land and building a log cabin in the middle of a meadow full of glacier lilies.

Cuckoo fears

Tuesday, 20 July 2010 13:07 UK

Watch our short film showing the flight of the cuckoo

A survey has revealed a steep decline in the number of cuckoos in the south west.

The population has fallen by nearly three-quarters since the mid '90s.

Tony Whitehead is from the RSPB in the South West.

He says: "The cuckoo's iconic song was once a common sound over much of the region, heralding summer and the return of warmer weather.

"Nowadays though, you'll be unlikely to hear a cuckoo anywhere away from the region's uplands and heaths.

"The reasons for this decline, and why it's so sharp in the south west, are not entirely clear although other long distant migrants are facing similar declines."

It's not just the much loved cuckoo that seems to be in trouble. Wildlife conservationists are also concerned about the decline of kestrels and swifts in the region.

Tony says: "The sight of kestrels hovering over road verges, or the sounds of swifts screaming above our houses in high summer is becoming a lot less common.

"For kestrels, more research into their declines is needed. From the '70s to the '90s agricultural intensification had its effects on these birds, but over the past decade more and more farmers have put measures in place on their land to help wildlife. This is really paying off for many species, but the kestrel seems still to have problems.

"With swifts, virtually the whole UK population nests in buildings. However improvements and the removal of access to lofts and roof spaces mean that increasingly the birds have no-where to go.

"We are working hard with developers and individuals to encourage the fitting of special swift nest boxes into buildings or designing special places for the birds in roof spaces."

The Breeding Bird Survey was carried out by countless volunteers across the UK.

http://news.bbc.co.uk/local/cornwall/hi/people_and_places/nature/newsid_8837000/8837996.stm
(Submitted by Liz R)

'Alarming decline' among London's house sparrows

20 July 2010

There has been an "alarming decline" in sparrows in London, the Royal Society for the Protection of Birds has said.

Its annual survey of the population of breeding birds has found a 68% drop in numbers compared with 15 years ago.

But it is unclear why this is the case, the society said, and a research project has been started.

Several species are on the increase, including robins, blue tits and magpies. The number of goldfinches has nearly trebled since 1995.

The number of house sparrows and song thrushes has declined more than in any other part of England, the report found.

This was "alarming", said the society's spokesman, Tim Webb.

"Their numbers are very low compared with historic levels and no-one knows why.

"Whatever is affecting them could be having an impact on our health and the wider environment," he added.

http://www.bbc.co.uk/news/uk-england-london-10695372
(Submitted by Liz R)

Watch out Mr Toad, Ratty's eating frogs

LONDON (Reuters) - British ecologists have discovered evidence that normally herbivorous water voles living alongside canals and rivers have been eating frogs' legs this Spring. The timid water vole, immortalised as "Ratty" in the "Wind in the Willows" children's novel and films, is Britain's fastest declining mammal and is known to have a largely vegetarian diet consisting of grass and plants.

05 May 2010 13:28 GMT

LONDON (Reuters) - British ecologists have discovered evidence that normally herbivorous water voles living alongside canals and rivers have been eating frogs' legs this Spring.

The timid water vole, immortalised as "Ratty" in the "Wind in the Willows" children's novel and films, is Britain's fastest declining mammal and is known to have a largely vegetarian diet consisting of grass and plants.

However, a survey along the Kennet & Avon Canal in the southern English county of Berkshire has revealed that these shy, furry animals have developed a taste for continental cuisine and have been snacking on frogs' legs, as well as the odd snail, British Waterways said in a statement on its website.

British Waterways ecologist Robert Randall said his team found a number of typical water vole feeding areas that were littered with dead frogs, minus their legs.

"We're not really sure why it's happening, but as the evidence coincides with the water voles' breeding season, we think it may be that pregnant mothers are snacking on frogs' legs as they lack protein in their diet," he added.

"This is incredibly unusual behaviour and as far as we know this is the first recorded evidence we have of them eating frogs' legs, so it's a really exciting discovery."

British Waterways asked people to report any water voles they see or any other wildlife activity in the country's canals and rivers on its website at www.waterscape.com/wildlifesurvey.

(Reporting by Paul Casciato; Editing by Steve Addison)

http://news.stv.tv/oddly-enough/175140-watch-out-mr-toad-rattys-eating-frogs/

Bat is winging its way back

Wednesday 3rd February 2010
By Peter Barrington

Rare lesser horseshoe bats are gradually making a re-appearance in Oxfordshire after being virtually absent for decades.

At one time, this species of bats was common across England, but it retreated to Wales and the West Country as habitats and sources of food declined due to old buildings being demolished or converted into houses or offices and changes in farming practices that saw many hedgerows uprooted to create larger fields.

Wildlife researchers and bat groups have begun finding evidence that the lesser horseshoes are moving eastwards and colonies have been discovered in the Welsh Marches, counties such as Shropshire and also in Gloucestershire and Wiltshire.

And lesser horseshoes have been seen by members of the Oxfordshire Bat Group further east in a variety of locations around the Chipping Norton area.

“We have known of two small colonies in disused railway tunnels for some time,” said Reg Tipping, a group member.

More recently, when members were carrying out a bat survey of buildings, the householder said: “What about the bat house?”

Mr Tipping said: “We thought what bat house? We had never heard of it. So we were taken to the old building nearby and found several lesser horseshoes were in residence. It was an exciting find.”

Since then, members have been quietly observing the bats in the spring and early summer to assess whether the colony was a summer or maternity roost.

A maternity roost is made up of predominantly females, although about 25 per cent could be males.

“We saw at one time that baby bats, or pups as they are known, were clinging to the adults,” said Mr Tipping.

Originally, it was thought the colony could have been a summer roost and an outpost of a larger colony over the county boundary in Gloucestershire. It was after consulting with an expert on lesser horseshoes, Henry Schofield, of the Vincent Wildlife Trust, based in Ledbury, that it was shown to be a colony in its own right.

Bat group members will keep an eye on all three groups in the Chipping Norton area, although they will be somewhat restricted as there is now no public access to the old railway tunnels for health and safety reasons.

“However, we believe these colonises show that this bat species is extending its range into Oxfordshire and we strongly suspect there are other colonies of the lesser horseshoes in that part of the county and possibly elsewhere,” said Mr Tipping.

There has also been a report of lesser horseshoes in Buckinghamshire, but the sighting has yet to be verified.

Over the course of a year, lesser horseshoes live in two locations.

Hibernating roosts in the winter months are often located in cool locations such as railway tunnels, where the temperature is fairly stable.

In the spring and summer, the bats like warmer sites like old buildings. The two roosts are sometimes not far apart, hence the need to differentiate between locations when a colony is found.

There are 17 species of bat in Britain and the lesser horseshoe and the greater horseshoe are among the rarest.

In the order of endangered species the greater are more at risk than the lesser horseshoes.

According to Henry Schofield, conservation programme manager for the Vincent Wildlife Trust, the greater horseshoes are restricted to the south and west of Wales and south-west England.

Lesser horseshoes declined about 50 to 60 years ago and are now found in Wales, the West Midlands, the West Country and along the south coast at least as far east as Dorset. They are also found in Ireland.

“We have been working on both lesser and greater horseshoes for some years and have set up about 40 bat reserves in Britain and Ireland for both species.

“We have tended to concentrate on the lessers in recent years because they are more widespread in England,” said Mr Schofield. The majority of lesser horseshoes are found in old buildings, usually of stone with slate roofs.

Mr Schofield said that most of these buildings were associated with old country estates and they included coach houses, churches, and even ice houses.

“We spend a lot of time enhancing the buildings, which become the reserves.

“It can sometimes mean a building is partly renovated because the lesser horseshoe, unlike some bats, cannot crawl and needs to be able to fly into a building to roost.

“This means entrances have to be modified.”

Mr Schofield attributed the previous national decline in lesser horseshoes to the loss of buildings in the countryside and the uprooting of hedges.

Lesser horseshoes feed off midges, found in hedgerows and at the edge of broadleaved woods.

They will also eat moths and crane flies.

He added: “Lesser horseshoes use their call, which is more high pitched than some other bats, to follow features of a landscape, such as hedges, to reach their food.

When he lived in North Wales he first became aware of the lesser horseshoes and has been fascinated by them ever since.

But why the name horseshoes?

“It is because of their face. They have a flap of skin around their nostrils, which we believe they use to make their call more directional, helping them to fly over the countryside and around buildings,” said Mr Schofield.

Findings of lesser horseshoes in Oxfordshire were a positive sign that the species was extending its range eastwards, he added.

http://www.oxfordtimes.co.uk/leisure/4888678.Bat_is_winging_its_way_back/

Thames eel populations crash by 98% in five years, scientists warn

Concerns grow over dramatic drop in numbers of mysterious creatures that migrate across the Atlantic

guardian.co.uk, Thursday 21 January 2010 17.34 GMT

Eel populations in the river Thames have crashed by 98% in just five years, scientists warned today.

The eel, which has been a traditional east London dish for centuries, now appears to be vanishing from the capital's river, according to researchers from the Zoological Society of London (ZSL).

Each year, ZSL's Tidal Thames Conservation Project places eel traps in a number of the river's tributaries, to catch the fish and allow scientists to record numbers before setting them free.

While 1,500 were captured in the traps in 2005, just 50 were recorded last year.

The eels are thought to take up to three years migrating as larvae from the Sargasso Sea to European rivers, where they spend up to 20 years before making the 4,000-mile return journey across the Atlantic to spawn and die.

But conservationists are concerned the species is not returning to the Thames, or is facing problems in the river and its tributaries.

European eels and flounders were the first species to recolonise the Thames estuary after it was considered "biologically dead" in the 1960s, and there are fears the rapid collapse of the eel population could have knock-on effects for other species in the still-fragile ecosystem.

Other rivers in the UK are also seeing declines in eel populations, ZSL said.

Dr Matthew Gollock, tidal Thames conservation project manager, said: "Eels are mysterious creatures at the best of times but we are very concerned about the rapid disappearance in the Thames.

"It is difficult to say what is going on – it could be due to a number of potential factors including changes in oceanic currents due to climate change, man-made structures such as dams and the presence of certain diseases and parasites."

And he said there was a need to find out why the declines were happening, in order to save the eels and help other species in the estuary's food web who would be affected by its disappearance, such as birds which feed on it.

"Time appears to be running out for eels in the river Thames and this could have a domino effect on other species in the Thames," Gollock said.

"The Thames is a very urban, developed estuary. It's much healthier than it was 50 years ago, but there is constant pressure on it.

"It's quite a precarious ecosystem and the fast removal of any species — whether it is a fish or a plant - is going to upset the balance," he said.

http://www.guardian.co.uk/environment/2010/jan/21/eel-thames-population-crash
(Submitted by Tim Chapman)

Puffins' winter odyssey revealed

Tuesday, 12 January 2010
By Mark Kinver
Science and environment reporter, BBC News

Puffins from the North Sea's largest breeding colony venture much further afield during the winter than previously thought, a study has shown.

More than 75% of the seabirds fitted with "geolocator" tags headed for the open waters of the Atlantic Ocean, rather than staying in the North Sea.

Until now, very little was known about where puffins went during the winter as the birds spent the entire time at sea.

The findings by British researchers appear in the journal Marine Biology.

Writing in the journal, a team of researchers from the Centre for Ecology and Hydrology said: "The finding that more than three-quarters of the birds made a major excursion into the Atlantic was entirely unexpected."

They added it challenged the previous view that puffin populations on the east and west of Britain remained separate from each other, during both the breeding season and during the winter.

"What we were completely unprepared for was that they made a one-to-three-month trip into the Atlantic and then came back to the North Sea," said lead author Mike Harris.

He said the development of geolocators - small location loggers that weigh 1.5g, which are fitted to birds' legs - allowed the team to track the puffins' movements for the first time.

"One of the big gaps in seabird biology is what do they do during the winter," Professor Harris explained.

"So, it's fantastic when all of these problems that you thought you would never solve, but then a technology appears that allows us to get somewhere at last.

"Up until now, the devices that have been available to fit on birds have been too heavy for puffins, which only weigh about 400g.

"So once these (geolocator) tags became available and were working well, the puffin was an obvious choice to use them on."

During the 2007 breeding season, the team fitted 50 birds on the Isle of May, a National Nature Reserve off the east coast of Scotland, with geolocators.

The loggers work by measuring light levels, recording when dawn and dusk occurs each day.

With this data, researchers can calculate day length, when midday occurs, and the daily longitudinal and latitudinal co-ordinates for the individual bird.

The researchers retrieved 14 devices during the following spring, and were able to download data from 13 of the tags.

Migration mystery

Professor Harris, who has been studying puffins for 37 years, said that it was too early to suggest why the puffins were making the extended journey to the Atlantic Ocean.

"At the moment, we are trying to get more information on what they eat," he told BBC News.

"We do not really know what species of fish or crustacea they eat during the winter; the suggestion is that they eat less fish and more plankton.

"The problem has been that until we know where they go, we cannot know what they are eating and whether there has been a change in [food availability].

Adverse conditions that limited the birds' access to food was one hypothesis for why there was a dramatic fall in the population of North Sea puffins between 2003 and 2008.

Puffin numbers on the Isle of May had been increasing for half a century, with the population reaching about 69,300 pairs in 2003.

Yet a survey in 2008 recorded 41,000 pairs, less than half of the 100,000 pairs that would be expected if the previous rate of increase had continued.

A similar decline in puffin numbers has also been recorded on the Farne Islands off the Northumberland coast, England's largest breeding colony of the seabirds.

A survey in 2008 recorded just 36,500 puffins, down from a record high of 55,674 in 2003.

Female puffins only lay one egg a year, so a high mortality rate among adults across a few years can quickly destabilise the population.

Professor Harris said that the population crash was unexpected.

"Puffins normally survive very well, and suddenly we had two years when they did not," he said.

Over the winter, the birds undergo their main moult in which they lose their wing feathers, making them flightless and vulnerable to adverse conditions, such as storms or poor food supplies.

Researchers are not sure how long puffins are left flightless, so the CEH team had hoped that a device on the tag that measured when the birds' feet were in seawater would provide an insight.

"What we didn't realise then but now know is that when puffins sleep they often tuck their feet into their plumage," Professor Harris revealed.

This behaviour meant that the tag dried out, recording an "in flight" reading when the bird in fact was still on the water.

"So we succeeded in one of our objectives, which was to find out where the puffins were going, but we failed on the other, which was to find out when the birds were flightless."

The team plan to continue fitting geolocators on puffins over the coming years, enabling them to build a better picture of the behaviour and movements of the birds during the winter months.

http://news.bbc.co.uk/1/hi/sci/tech/8452423.stm

Reindeer herds in global decline

08:49 GMT, Thursday, 11 June 2009 09:49 UK
Matt Walker Editor, Earth News

Reindeer and caribou numbers are plummeting around the world.

The first global review of their status has found that populations are declining almost everywhere they live, from Alaska and Canada, to Greenland, Scandinavia and Russia.

The iconic deer is vital to indigenous peoples around the circumpolar north.

Yet it is increasingly difficult for the deer to survive in a world warmed by climate change and altered by industrial development, say scientists.

Reindeer and caribou belong to the same species, Rangifer tarandus.

Caribou live in Canada, Alaska and Greenland; while reindeer live in Russia, Norway, Sweden and Finland.

Worldwide, seven sub-species are recognised. Each are genetically, morphologically and behaviourally a little different, though capable of interbreeding with one another.

These differences between sub-species dictate how each is affected by human impacts.

For example, it has been known for a while that populations of woodland caribou in Canada have declined as human disturbance has increased, caused by logging, oil and gas exploration, and road building, says Liv Vors of the University of Alberta in Edmonton, Canada.

But then reports started coming in that the numbers of other herds were also falling.

"When we discovered that many herds of reindeer also were declining we decided to compile a comprehensive survey to see if this indeed was a global pattern," says Vors.

Vors and Mark Boyce at the University of Alberta contacted other researchers and scoured the published literature and government databases for all the information they could find about reindeer and caribou numbers. They compiled data on 58 major herds around the Northern Hemisphere.

The scientists were shocked to discover that 34 of the herds were declining, while no data existed for 16 more. Only eight herds were increasing in number. Many herds had been declining for a decade or more.

"We were surprised at the ubiquity of the decline," says Vors.

"We knew that woodland caribou in North America were in bad shape." There is also some evidence that populations of migratory caribou in the Canadian Arctic have fluctuated in recent history.

But the researchers were surprised at how migratory caribou and reindeer numbers seem to be falling in synchrony across the Northern Hemisphere.

"When we delved into the status of European reindeer herds, we were surprised that so many were declining. We expected them to be in better shape than North America herds because reindeer, namely the semi-domestic herds, are closely managed by humans."

The scale of the problem is shown by a map upon which the researchers plotted their data, which is published in Global Change Biology.

"Seeing that sea of red was a sobering moment," Vors says.

"If global climate change and industrial development continue at the current pace, caribou and reindeer populations will continue to decline in abundance," says Vors.

"Currently, climate change is most important for Arctic caribou and reindeer, while anthropogenic landscape change is most important for non-migratory woodland caribou."

For example, climate change is affecting migratory caribou in a number of ways.

Warmer summers mean more insect activity, and caribou and reindeer that are harassed by insects are not able to feed as much to put on weight before winter.

Earlier springs mean plants may be past their prime by the time migrating animals reach their calving grounds, while warmer winters include more freezing rain which can form layers of ice over the ground. The caribou and reindeer cannot dig through the ice to feed, and can then starve en masse.

"In time, however, climate change will become more important for woodland caribou, and landscape change will have a greater effect on arctic caribou and reindeer," Vors continues.

"There likely will be more forest fires in woodland caribou habitat, as well as diseases and parasites transmitted to caribou from white-tailed deer, whose range is expanding northward in Canada. More roads are being built in the Arctic, as well as infrastructures like diamond mines, and these sometimes interfere with migration routes."

Unless something is urgently done, all seven sub-species of Rangifer face a bleak future, says Vors.

"The concern is that their habitat and the climate are changing too quickly for them to adapt."

The annual treks of migratory caribou form one of the last remaining large-scale ungulate migrations in the northern hemisphere.

Different sub-species also provide a cornerstone to many indigenous cultures around the circumpolar north, from subsistence hunting of caribou by Aboriginal peoples in Canada, Greenland and Alaska to reindeer husbandry by numerous cultures across Scandinavia and Siberia.

"From a Canadian perspective, the caribou is part of our national identity," says Vors. "Canada's caribou migrations have frequently been identified as one of this country's natural wonders, and the species even appears on our 25-cent coin."

http://news.bbc.co.uk/earth/hi/earth_news/newsid_8094000/8094036.stm