Wildlife decline may lead to 'empty landscape'

Populations of some of the world's largest wild animals are dwindling, raising the threat of an "empty landscape", say scientists.

The threatened black rhino

About 60% of giant herbivores - plant-eaters - including rhinos, elephants and gorillas, are at risk of extinction, according to research.

Analysis of 74 herbivore species, published in Science Advances, blamed poaching and habitat loss.

A previous study of large carnivores showed similar declines.

Prof William Ripple, of Oregon State University, led the research looking at herbivores weighing over 100kg, from the reindeer up to the African elephant.

"This is the first time anyone has analysed all of these species as a whole," he said.

"The process of declining animals is causing an empty landscape in the forest, savannah, grasslands and desert."

The threatened mountain zebra

Prof David Macdonald, of Oxford University's Wildlife Conservation Research Unit, was among the team of 15 international scientists.

"The big carnivores, like the charismatic big cats or wolves, face horrendous problems from direct persecution, over-hunting and habitat loss, but our new study adds another nail to their coffin - the empty larder," he said.

"It's no use having habitat if there's nothing left to eat in it."

According to the research, the decline is being driven by a number of factors including habitat loss, hunting for meat or body parts, and competition for food and resources with livestock.

With rhinoceros horn worth more than gold, diamonds or cocaine on illegal markets, rhinos could be extinct in the wild within 20 years in Africa, said the researchers.

The consequences of large wild herbivore decline include:

• Loss of habitat: for example, elephants maintain forest clearings by trampling vegetation

• Effects on the food chain: large predators such as lions, leopards, and hyena rely on large herbivores for food

• Seed dispersal: large herbivores eat seeds which are carried over long distances

• Impact on humans: an estimated one billion people rely on wild meat for subsistence while the loss of iconic herbivores will have a negative impact on tourism

The biggest losses are in South East Asia, India and Africa.

Europe and North America have already lost most of their large herbivores in a previous wave of extinctions.

From BBC Science

New York turns off its lights to help birds

A plan has been announced to turn off the lights on some big buildings in New York City this spring and autumn because of worries about the effect they're having on birds.

As the seasons change lots of birds fly from one part of America to another.

But their journey through New York isn't always so smooth, particularly at night.

That's because birds use the stars in the sky to help them figure out where they're going in the dark.

But with so many bright lights in the city, they get confused and don't end up in the right place.

So the mayor has decided to turn off outdoor lights on public buildings which aren't needed.

From 11pm in the evening, it'll be a whole lot darker for New Yorkers... but hopefully a lot easier for their feathery friends.

From BBC News

Baby Cuban crocs return to wild

Ten baby Cuban crocodiles are heading from Sweden to Cuba to help save the endangered reptile.

For over 30 years Cuban crocs have been bred in a zoo in Sweden, Europe.

But now some of the young reptiles are ready for life in the wild and have started their long journey to Cuba in the Caribbean.This species of croc is today only found in the wild in two swamps in Cuba.

It's thought there are around 100 purebred Cuban crocs there today.

From CBBC Newsround

Nepal quake 'followed historic pattern'

Nepal's devastating magnitude-7.8 earthquake on Saturday was primed over 80 years ago by its last massive earthquake in 1934, which razed around a quarter of Kathmandu to the ground and killed over 17,000 people.

This latest quake follows the same pattern as a duo of big tremors that occurred over 700 years ago, and results from a domino effect of strain transferring along the fault, geologists say.

The researchers discovered the likely existence of this doublet effect only in recent weeks, during field work in the region.

Saturday's quake, which struck an area in central Nepal, between the capital Kathmandu and the city of Pokhara, has had a far-reaching impact.

Early reports indicate that nearly 2,000 people have lost their lives, with victims in Bangladesh, India, Tibet, and on Mount Everest, where avalanches were triggered.

Death tolls and casualty figures are likely to rise over the coming days, and the risk of landslides on slopes made unstable by the quake mean that the danger is far from passed.

A sadly prescient turn of events: Geologists uncovered historic connections only weeks ago

Trench investigations

In a sadly prescient turn of events, Laurent Bollinger, from the CEA research agency in France, and his colleagues, uncovered the historical pattern of earthquakes during fieldwork in Nepal last month, and anticipated a major earthquake in exactly the location where Saturday's big tremor has taken place.

Down in the jungle in central southern Nepal, Bollinger's team dug trenches across the country's main earthquake fault (which runs for more than 1,000km from west to east), at the place where the fault meets the surface, and used fragments of charcoal buried within the fault to carbon-date when the fault had last moved.

Ancient texts mention a number of major earthquakes, but locating them on the ground is notoriously difficult.

Monsoon rains wash soils down the hillsides and dense jungle covers much of the land, quickly obscuring earthquake ruptures.

Bollinger's group was able to show that this segment of fault had not moved for a long time.

"We showed that this fault was not responsible for the great earthquakes of 1505 and 1833, and that the last time it moved was most likely 1344," says Bollinger, who presented his findings to the Nepal Geological Society two weeks ago.

Previously, the team had worked on the neighbouring segment of fault, which lies to the east of Kathmandu, and had shown that this segment experienced major quakes in 1255, and then more recently in 1934.

The deadly pattern of quakes around Kathmandu

• Saturday's magnitude-7.8 earthquake struck to the north-west of Kathmandu
• The last time the fault ruptured at this location was in back in 1344
• It was preceded in 1255 by a big event to the east of Kathmandu
• The last rupture there was in 1934, hinting strain might accumulate westward
• 2015's quake follows the pattern with a gap between events of 80 years or so

When Bollinger and his colleagues saw this historic pattern of events, they became greatly concerned.

"We could see that both Kathmandu and Pokhara would now be particularly exposed to earthquakes rupturing the main fault, where it likely last did in 1344, between the two cities," explains Paul Tapponnier, from the Earth Observatory of Singapore, who was working with Bollinger.

When a large earthquake occurs, it is common for the movement to transfer strain further along the earthquake fault, and this seems to be what happened in 1255.

Over the following 89 years, strain accumulated in the neighbouring westerly segment of fault, finally rupturing in 1344.

Now, history has repeated itself, with the 1934 fault transferring strain westwards along the fault, which has finally been released today, 81 years later.

And, worryingly, the team warns there could be more to come.

"Early calculations suggest that Saturday's magnitude-7.8 earthquake is probably not big enough to rupture all the way to the surface, so there is still likely to be more strain stored, and we should probably expect another big earthquake to the west and south of this one in the coming decades," says Bollinger.

From BBC Science/Environment