Killing Rats Could Save Coral Reefs
The much maligned rat is not a creature many would associate with coral reefs. But scientists studying reefs on tropical islands say the animals directly threaten the survival of these ecosystems. A team working on the Chagos Islands in the Indian Ocean found that invasive rats on the islands are a "big problem" for coral reefs. Rats decimate seabird populations, in turn decimating the volume of bird droppings - a natural reef fertilizer. The findings are published in the magaazine
Nature. Scientists now advocate eradicating rats from all of the islands to protect these delicate marine habitats.
How do rats harm coral reefs?
The Chagos Archipelago provided a large-scale natural laboratory to answer this question; although the islands are uninhabited by humans, some of them are now home to invasive rats, brought by ships and shipwrecks. Other islands have remained rat-free. "The islands with and without rats are like chalk and cheese," said lead researcher Professor Nick Graham from LancasterUniversity. "The islands with no rats are full of birds, they're noisy, the sky is full and they smell - because the guano the birds are depositing back on the island is very pungent."If you step onto an island with rats, there are next to no seabirds." By killing seabirds, this study revealed, rats disrupt a healthy ecosystem that depends on the seabird droppings, which fertilize the reefs surrounding the island. On rat-free islands, seabirds including boobies, frigate birds, noddies, shear-waters and terns travel hundreds of kilometers to feed out in the ocean. When they return to the island, they deposit rich nutrients from the fish they feed on."These nutrients are leaching out onto the reef," explained Professor Graham.He and his team were able to track the source of those nutrients back to the fish that seabirds fed on by analyzing algae and sponges growing on the reef. "We also found that fish on the reefs adjacent to islands with seabirds were growing faster and were larger for their age than the fish on reefs next to rat-infested islands," Prof Graham explained. There were also significantly more fish on rat-free reefs than on those around "ratty islands".
Why does this matter?
Coral reefs cover less than 0.1% of the ocean's area, but house about one third of ocean biodiversity. "Coral reefs are also hugely threatened," said Professor Graham. "So anyone who cares about extinctions and biodiversity needs to care about the future of coral reefs." The reefs and their abundance of marine life provide livelihoods for millions of people around the world, so the decline in coral reefs is poised to become a humanitarian crisis.In an accompanying commentary article Doctor Nancy Knowlton, a marine scientist, a marine scientist from the Smithsonian's National Museum of Natural History in Washington, DC, pointed out that, while "adding rats to the list of dangers faced by reefs might seem discouraging, the discovery of these negative impacts points directly to a specific strategy" that could slow the ongoing degradation of reefs. That strategy - rat eradication on islands throughout the world - is exactly what the researchers who carried out this study now advocate. "Coral reef systems are at crisis point because of climate change," said Prof Graham. "And we're desperately trying to find ways to enhance the resilience of coral reefs and allow them to cope with climate change. "This is one of the clearest examples so far, where eradicating rats will lead to increased numbers of seabirds and this will bolster the coral reef."
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Heat-wave Reveals Submerged Mourne history At Spelga Dam
It is not quite the Lost City of Atlantis but at the gateway to County Down's Mourne mountains a hidden-underwater history has been revealed. Spelga Reservoir is often full to the brim with water stored to serve parts of counties Down and Armagh. But the recent heat-wave and dry weather has caused its supply to drop, exposing what lies on the reservoir bed. Hundreds of people have been visiting the dam to walk along an old road that usually sits well below the waterline. The reservoir covers an area known as Deer's Meadow, which was flooded after Spelga Dam was constructed in the 1950's, creating the 600,000sq m (6.46 million sq ft) basin. Dividing the meadow was a road that passed between the mountains, connecting Hilltown village on one side of the Mournes with the fishing town of Kilkeel on the other. It too was submerged, with a new road built in its place on higher ground around the area of the reservoir - it is the one that is used to this day. Now standing well above the water's surface is the old, original road that dates back to the early-1800's and features a small bridge that spanned the River Bann, which originates at nearby Slieve Muck. Doctor Arthur Mitchell, a well-known figure in the Mournes, remembers travelling on the old road before the dam was built. He worked as a GP in the area for almost 40 years and formed the Mourne Heritage Trust, a conservation group that looks after the mountain range. "I lived in Downpatrick at the time and I drove over the old road up through Spelga - it was an exceptionally busy road," he said. "The new road had to be built because the old road ran directly through the valley, so the new road had to detour round the dam and fall away down the valley towards Hilltown." Even with the intoductionof a hosepipe banin Northern Ireland at the end of June.in a bid to save water, Spelga Reservoir has continued to drain. While its water level does occasionally dip to a point at which you can see the surface of the old road, it is much less frequent to get a chance to see the bridge - the last time was in 2014. Now in his 80's, Doctor Mitchell has passed along the more recent road around the reservoir many hundreds of times. "I have seen Spelga very low before but I don't think it's been so exposed for such a prolonged time as it has been this summer," he said. "The ground around the bridge is exposed too and the original riverbed - the source of the Bann - is clearly visible at the minute under the original road because the water has fallen so dramatically." Before Deer's Meadow was flooded it was a prime site for cutting turf for fuelling fires, with farmers from the nearby towns and villages making their way up to it both for work and for play, according to Doctor Mitchell. "Many's a one, when they were cutting turf, ended up with a woman from Hilltown or a woman from Kilkeel - turf cutting was also a social affair." Dairy cows grazed on the neighbouring and aptly-named Butter Mountain and pigs were farmed on Slieve Muck, which overlooks Spelga. The tree stumps on the reservoir bed - now exposed as the water has receded - have a wartime tale to tell. "They are mostly Scots pine and they provided virtually all of the firewood for the Kilkeel and Hilltown areas during the coal strike after World War One," said Doctor Mitchell. And the reservoir's low level is giving new generations an insight in to what were once the ways of life. "It proves that there was a road through the centre of the Mournes and that those previous social habits and work took place in the mountains - it makes hearsay a reality."
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British Survey: Half Of Young People Want Electric Cars
Half of young people in the U.K. would like to own an electric car - compared with just a quarter of their parents, a survey suggests. The research comes from motoring group the AA, which says myths about electric vehicles are putting off many drivers. This matters because cleaning up air pollution and tackling climate change both depend on mass acceptance of electric vehicles (EVs). Young people seem to be more accepting of the technology than older people. But, too many still hold needless fears the AA says. It comes as the government has announced a target for 50% of all new vehicle sales to be in the ultra-low emissions category by 2030. The opinions were revealed in an AA/Populus poll of 10,293 drivers.
What The AA Thinks
There are 16,000 charging points at 5,800 locations and 340 points added monthly. Most drivers will charge theis cars at home. Range is improving all the time. Several models have a 250-mile-plus range. Some 95% of car journeys are under 25 miles. Costs are coming down. Grants up to £4,500 are available and EVs are much cheaper to run - at 2p per mile. Rapid chargers which could charge an EV to around 80% range in around 30 minutesare on the way - ideal for "filling stations". There are 38 cars eligible for plug-in grants from a Renault Zoe to Jaguar I-PACE and more on the horizon, such as the Tesla Model 3. The AA’s president Edmund King said: “The range, charging speed and charging point infrastructure are all on the increase. There needs to be a more concerted effort by us all to sell the benefits of electric vehicles. “Drivers will also need to change their fuelling habits with the majority charging their EVs at night (at home) and then at their destinations. “Ultimately outstanding, affordable, stylish EVs with a decent range will sell themselves. Massive savings can already be made on running and service costs, as well as the tax benefits.” “The younger generation in particular are ready to embrace the electric revolution.”
