Tag Archives: Mountains

Mountains rich in species still puzzle science

Life on Earth is ultimately a mystery. Even more of a riddle is why there are so many mountains rich in species.

LONDON, 16 September, 2019 − Danish ecologists have begun to wrestle with one of life’s great unsolved puzzles: why does the world have so many ranges of mountains rich in species?

This is not just a question for the intellectual high ground. As many as a million species of amphibian, fish, bird, reptile, mammal, insect or plant could be threatened by climate change and the destruction of forest habitat by human action this century.

But forests – if conserved and protected – could play a vital role in mitigating climate change, and researchers have repeatedly found that undisturbed forests hold the greatest levels of biodiversity, and conversely that biodiversity is important to the stability of the great forests.

But when biologists look more closely at the challenge of explaining biodiversity, they are confronted by something unexpected. The richest landscapes on the planet are the tropical and subtropical mountain chains. And the richest of all are the northern Andean chain.

This stretch of soaring peaks and woodland valleys is the most species-rich of all, with 45,000 kinds of flowering plant, 44% of which are found only in that region.

“Mountains, with their uniquely complex environments and geology, have allowed the continued persistence of ancient species deeply rooted in the tree of life”

There are huge concentrations of living things in the highlands of China’s Sichuan and Yunnan, the East African Highlands and the mountains of New Guinea. These contours of ridge and valley occupy only 25% of the inhabited continents, but they are home to 85% of amphibians, birds and mammals.

And of this population of vertebrates, more than half are found only in mountain ranges. To mark the 250th anniversary of the birth of the great explorer Alexander von Humboldt, scientists have dubbed this question “the Humboldt enigma”.

In 1799 Humboldt began a five-year voyage of discovery through Latin America, and made history by mapping the way vegetation changed with altitude on Mt Chimborazo in Ecuador.

“The challenge is that, although it is evident that much of the global variation in biodiversity is so clearly driven by the extraordinary richness of tropical mountain regions, it is this very richness that current biodiversity models, based on contemporary climate, cannot explain,” said Carsten Rahbek of the University of Copenhagen and Imperial College London, who led the research, published in the journal Science.

“Mountains are simply too rich in species, and we are falling short of explaining global hotspots of biodiversity.”

Search for principles

Professor Rahbek was one of a team that, five years ago, measured changes of colour in butterflies and dragonflies that could be linked to changes in European temperatures in a world of global heating.

That is, evolution seemed to be responding to environmental change. Scientists call this sort of research macroecology: the search for the principles behind change, rather than the details of change.

There could hardly be a bigger macroecological question than one that concerns the location of the richest concentrations of life’s variety. Climatic variation – including the shifts in temperature with altitude – is clearly a factor.

Geology – because mountains are where bedrock tends to be most exposed – emerges as another factor in the two papers in Science.

Open question

Professor Rahbek describes the studies as testament to the pioneering science of Humboldt more than two centuries ago. The Humboldt enigma, for the moment, remains an open question.

Conservation scientists know that climate change and habitat destruction driven by human behaviour threatens the bewildering richness of life on Earth. But they still don’t know quite why life on Earth is so bewilderingly rich, and especially why it is so rich in relatively confined hotspots.

“The global pattern of biodiversity shows that mountain biodiversity exhibits a visible signature of past evolutionary processes,” Professor Rahbek said.

“Mountains, with their uniquely complex environments and geology, have allowed the continued persistence of ancient species deeply rooted in the tree of life, as well as being cradles where new species have arisen at a much higher rate than in lowland areas, even in areas as amazingly biodiverse as the Amazonian rainforest.” − Climate News Network

Life on Earth is ultimately a mystery. Even more of a riddle is why there are so many mountains rich in species.

LONDON, 16 September, 2019 − Danish ecologists have begun to wrestle with one of life’s great unsolved puzzles: why does the world have so many ranges of mountains rich in species?

This is not just a question for the intellectual high ground. As many as a million species of amphibian, fish, bird, reptile, mammal, insect or plant could be threatened by climate change and the destruction of forest habitat by human action this century.

But forests – if conserved and protected – could play a vital role in mitigating climate change, and researchers have repeatedly found that undisturbed forests hold the greatest levels of biodiversity, and conversely that biodiversity is important to the stability of the great forests.

But when biologists look more closely at the challenge of explaining biodiversity, they are confronted by something unexpected. The richest landscapes on the planet are the tropical and subtropical mountain chains. And the richest of all are the northern Andean chain.

This stretch of soaring peaks and woodland valleys is the most species-rich of all, with 45,000 kinds of flowering plant, 44% of which are found only in that region.

“Mountains, with their uniquely complex environments and geology, have allowed the continued persistence of ancient species deeply rooted in the tree of life”

There are huge concentrations of living things in the highlands of China’s Sichuan and Yunnan, the East African Highlands and the mountains of New Guinea. These contours of ridge and valley occupy only 25% of the inhabited continents, but they are home to 85% of amphibians, birds and mammals.

And of this population of vertebrates, more than half are found only in mountain ranges. To mark the 250th anniversary of the birth of the great explorer Alexander von Humboldt, scientists have dubbed this question “the Humboldt enigma”.

In 1799 Humboldt began a five-year voyage of discovery through Latin America, and made history by mapping the way vegetation changed with altitude on Mt Chimborazo in Ecuador.

“The challenge is that, although it is evident that much of the global variation in biodiversity is so clearly driven by the extraordinary richness of tropical mountain regions, it is this very richness that current biodiversity models, based on contemporary climate, cannot explain,” said Carsten Rahbek of the University of Copenhagen and Imperial College London, who led the research, published in the journal Science.

“Mountains are simply too rich in species, and we are falling short of explaining global hotspots of biodiversity.”

Search for principles

Professor Rahbek was one of a team that, five years ago, measured changes of colour in butterflies and dragonflies that could be linked to changes in European temperatures in a world of global heating.

That is, evolution seemed to be responding to environmental change. Scientists call this sort of research macroecology: the search for the principles behind change, rather than the details of change.

There could hardly be a bigger macroecological question than one that concerns the location of the richest concentrations of life’s variety. Climatic variation – including the shifts in temperature with altitude – is clearly a factor.

Geology – because mountains are where bedrock tends to be most exposed – emerges as another factor in the two papers in Science.

Open question

Professor Rahbek describes the studies as testament to the pioneering science of Humboldt more than two centuries ago. The Humboldt enigma, for the moment, remains an open question.

Conservation scientists know that climate change and habitat destruction driven by human behaviour threatens the bewildering richness of life on Earth. But they still don’t know quite why life on Earth is so bewilderingly rich, and especially why it is so rich in relatively confined hotspots.

“The global pattern of biodiversity shows that mountain biodiversity exhibits a visible signature of past evolutionary processes,” Professor Rahbek said.

“Mountains, with their uniquely complex environments and geology, have allowed the continued persistence of ancient species deeply rooted in the tree of life, as well as being cradles where new species have arisen at a much higher rate than in lowland areas, even in areas as amazingly biodiverse as the Amazonian rainforest.” − Climate News Network

Bolivian glaciers melt at alarming rate

glaciers

A new study mapping the effects of dwindling glaciers on people living in Bolivia reveals rapid shrinkage and potentially dangerous glacial lakes.

LONDON, 22 October, 2016 Between 1986 and 2014 – one human generation – the glaciers of Bolivia shrank by 43%, according to new research.

This presents a problem in the long term for more than 2 million people who rely on glacial meltwater supply in the dry season, and immediate danger in the short term for thousands who might live below precarious glacial lakes.

Glaciers are in retreat as the world warms − a consequence of rising levels of carbon dioxide in the atmosphere in response to the increasing combustion of fossil fuels.

They are dwindling almost everywhere in the Andean chain, in Greenland, in Alaska and Canada, the Himalayas, across the entire mass of Central Asia, and everywhere in the tropics.

Tropical glaciers

But a new study in The Cryosphere, the journal of the European Geosciences Union, is one of the first to examine in detail precisely what this retreat could mean for the human communities in Bolivia, home to one-fifth of the world’s tropical glaciers.

Researchers from two British universities and a Bolivian colleague examined NASA satellite images of the region and found that the area of the Bolivia Cordillera Oriental normally covered by glaciers fell from 530 square kilometres in 1986 to about 300 sq km in 2014 − a shrinkage of more than two-fifths.

They then turned to the glacial lakes − bodies of water left behind as a glacier retreats. Some are in natural dips in the bedrock, some are accidentally dammed behind walls of glacial debris.

All such lakes are precarious: rockfalls, earthquakes and avalanches can breach them or tip water from them to create a dangerous downstream flow.

We mapped hundreds of lakes,” says Simon Cook, senior lecturer in physical geography at Manchester Metropolitan University, who led the study.

Some lakes are very small and pose little risk. Others are very large, but there’s little or no possibility that they would drain catastrophically. Others are large enough to create a big flood, and sit beneath steep slopes or steep glaciers, and could be dangerous.”

Studies such as these are a demonstration that climate change is happening, and that science can deliver practical help to communities in the path of potential disaster or economic stress.

Most glaciers will be gone or much diminished
by the end of the century – so where will the water come from in the dry season?”

Civil engineers, geographers, conservationists and hydraulic engineers are no longer simply warning about the hazards of climate change. They have begun to identify the communities most vulnerable to flooding, the hazards to local biodiversity as forests and grasslands begin to feel the heat, and the cities most at risk from routine coastal flooding as sea levels rise. and the US states that must start planning now for future power disruption as a consequence of drought.

Meltwater matters to mountain communities. It supplies the drive for hydroelectric power and it delivers clean drinking water to the cities and irrigation for crops in the dry season.

Reservoirs at risk

Through the year, the 2.3 million people in the Bolivian cities of La Paz and El Alto get 15% of their water from glacial supplies; in the dry season, this figure doubles. Glacial meltwater also keeps regional rivers and lakes topped up. So as the glaciers retreat and the body of surviving ice dwindles, some of these reservoirs, too, are at risk.

The researchers pinpointed 25 lakes as potentially dangerous. Even the smallest, were it to drain completely, would tip a peak flow of 600 cubic metres of water a second down the hillside. The largest could discharge 125,000 cubic metres − 50 times the volume of an Olympic swimming pool − every second.

A glacial lake outburst in 2009 killed farm animals, destroyed crops and washed away a road, leaving villagers isolated for months.

Dr Cook says: “We considered that a lake was dangerous if there were settlements or infrastructure down-valley from the lake, and if the slopes and glaciers around the lake were very steep, meaning that they could shed ice or snow or rock into the lake, which would cause it to overtop and generate a flood – a bit like jumping into a swimming pool, but on a much bigger scale.

Most glaciers will be gone or much diminished by the end of the century – so where will the water come from in the dry season?

Big cities like La Paz are partially dependent on meltwater from glaciers. But little is known about potential water resource stress in more remote areas. Much more work needs to be done on this issue.” Climate News Network

A new study mapping the effects of dwindling glaciers on people living in Bolivia reveals rapid shrinkage and potentially dangerous glacial lakes.

LONDON, 22 October, 2016 Between 1986 and 2014 – one human generation – the glaciers of Bolivia shrank by 43%, according to new research.

This presents a problem in the long term for more than 2 million people who rely on glacial meltwater supply in the dry season, and immediate danger in the short term for thousands who might live below precarious glacial lakes.

Glaciers are in retreat as the world warms − a consequence of rising levels of carbon dioxide in the atmosphere in response to the increasing combustion of fossil fuels.

They are dwindling almost everywhere in the Andean chain, in Greenland, in Alaska and Canada, the Himalayas, across the entire mass of Central Asia, and everywhere in the tropics.

Tropical glaciers

But a new study in The Cryosphere, the journal of the European Geosciences Union, is one of the first to examine in detail precisely what this retreat could mean for the human communities in Bolivia, home to one-fifth of the world’s tropical glaciers.

Researchers from two British universities and a Bolivian colleague examined NASA satellite images of the region and found that the area of the Bolivia Cordillera Oriental normally covered by glaciers fell from 530 square kilometres in 1986 to about 300 sq km in 2014 − a shrinkage of more than two-fifths.

They then turned to the glacial lakes − bodies of water left behind as a glacier retreats. Some are in natural dips in the bedrock, some are accidentally dammed behind walls of glacial debris.

All such lakes are precarious: rockfalls, earthquakes and avalanches can breach them or tip water from them to create a dangerous downstream flow.

We mapped hundreds of lakes,” says Simon Cook, senior lecturer in physical geography at Manchester Metropolitan University, who led the study.

Some lakes are very small and pose little risk. Others are very large, but there’s little or no possibility that they would drain catastrophically. Others are large enough to create a big flood, and sit beneath steep slopes or steep glaciers, and could be dangerous.”

Studies such as these are a demonstration that climate change is happening, and that science can deliver practical help to communities in the path of potential disaster or economic stress.

Most glaciers will be gone or much diminished
by the end of the century – so where will the water come from in the dry season?”

Civil engineers, geographers, conservationists and hydraulic engineers are no longer simply warning about the hazards of climate change. They have begun to identify the communities most vulnerable to flooding, the hazards to local biodiversity as forests and grasslands begin to feel the heat, and the cities most at risk from routine coastal flooding as sea levels rise. and the US states that must start planning now for future power disruption as a consequence of drought.

Meltwater matters to mountain communities. It supplies the drive for hydroelectric power and it delivers clean drinking water to the cities and irrigation for crops in the dry season.

Reservoirs at risk

Through the year, the 2.3 million people in the Bolivian cities of La Paz and El Alto get 15% of their water from glacial supplies; in the dry season, this figure doubles. Glacial meltwater also keeps regional rivers and lakes topped up. So as the glaciers retreat and the body of surviving ice dwindles, some of these reservoirs, too, are at risk.

The researchers pinpointed 25 lakes as potentially dangerous. Even the smallest, were it to drain completely, would tip a peak flow of 600 cubic metres of water a second down the hillside. The largest could discharge 125,000 cubic metres − 50 times the volume of an Olympic swimming pool − every second.

A glacial lake outburst in 2009 killed farm animals, destroyed crops and washed away a road, leaving villagers isolated for months.

Dr Cook says: “We considered that a lake was dangerous if there were settlements or infrastructure down-valley from the lake, and if the slopes and glaciers around the lake were very steep, meaning that they could shed ice or snow or rock into the lake, which would cause it to overtop and generate a flood – a bit like jumping into a swimming pool, but on a much bigger scale.

Most glaciers will be gone or much diminished by the end of the century – so where will the water come from in the dry season?

Big cities like La Paz are partially dependent on meltwater from glaciers. But little is known about potential water resource stress in more remote areas. Much more work needs to be done on this issue.” Climate News Network