Ecology // Current TV

Meet the Herbicide Industry’s Worst Enemy – The Frog of War

When biologist Tyrone Hayes discovered that a top-selling herbicide messes with sex... more

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Ecological kings of the jungle being toppled by drought, pests, and disease

The biggest trees in the world, known as the true ecological kings of the jungle, are dying off rapidly as roads, farms and settlements fragment forests and they come under prolonged attack from severe droughts and new pests and diseases.

Big trees may comprise less than 2% of the trees in any forest but they can contain 25% of the total biomass and are vital for the health of the whole forest. Credit: us-parks.com

Long-term studies in Amazonia, Africa and Central America show that while these botanical behemoths may have adapted successfully to centuries of storms, pests and short-term climatic extremes, they are counter-intuitively more vulnerable than other trees to today's threats.

"Fragmentation of the forests is now disproportionately affecting the big trees," said William Laurance, a research professor at James Cook University in Cairns, Australia. "Not only do many more trees die near forest edges, but a higher proportion of the trees dying were the big trees.

"Their tall stature and relatively thick, inflexible trunks, may make them especially prone to uprooting and breakage near forest edges where wind turbulence is increased," Laurance said in this week's New Scientist magazine.

Big trees may comprise less than 2% of the trees in any forest but they can contain 25% of the total biomass and are vital for the health of whole forests because they seed large areas. "With their tall canopies basking in the sun, big trees capture vast amounts of energy. This allows them to produce massive crops of fruits, flowers and foliage that sustain much of animal life in the forests. Their canopies help moderate the local forest environment while their understory creates a unique habitat for other plants and animals," Laurance said.

"Only a small number of tree species have the genetic capacity to grow really big. To grow into giants, trees need good growing conditions, lots of time and the right place to establish their seedlings. Disrupt any one of these and you lose them."

In some parts of the world, Laurance said, populations of big trees are dwindling because their seedlings cannot survive or grow. "In southern India an aggressive shrub is invading the understorey of many forests, preventing seedlings from dropping on the floor. With no young trees to replace them, it's only a matter of time before most of the big trees disappear."

According to Laurance, it is not just the biggest trees in the world that are suffering, but also the biggest in their communities. Dutch elm disease killed off many of the stateliest trees in Britain in the 1960s and 70s, and new exotic organisms and bacterial infections, often brought in from other continents via garden centers, are threatening oak, ash and other species.

Longer lasting and more intense droughts, which are becoming more frequent in many tropical areas with climate change, are also taking their toll. Studies in Puerto Rico and Costa Rica suggest that big trees also suffer more in droughts than most other organisms.

"In rainforests droughts promote surface fires that burn through leaf litter on the forest floor. Larger trees were initially thought to survive these fires but, in fact, many die two to three years later. In cloud forests, big trees use their branches and crowns to rake the mist and capture water droplets. Global warming could push clouds up to higher elevations depriving them of sources of moisture," Laurance said.

"The danger is that the oldest, largest trees will progressively die off and not be replaced. Alarmingly, this might trigger a 'positive feedback' that could destabilize the climate: as older trees die, forests would release their stored carbon, prompting a vicious circle of further warming and forest shrinkage."
more at the linkThe biggest trees in the world, known as the true ecological kings of the jungle, are... more

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8 days ago
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10 marine species on the brink of mass extinction due to ocean acidification

The ocean is a delicate place, and tiny changes to its composition can cause serious... more

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9 days ago
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Carbon dioxide is driving fish crazy

Rising human carbon dioxide emissions may be affecting the brains and central nervous... more

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12 days ago
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31 comments

Climate change may bring big ecosystem changes

By 2100, global climate change will modify plant communities covering almost half of Earth's land surface and will drive the conversion of nearly 40 percent of land-based ecosystems from one major ecological community type - such as forest, grassland or tundra - toward another, according to a new NASA and university computer modeling study.

Researchers from NASA's Jet Propulsion Laboratory and the California Institute of Technology in Pasadena, Calif., investigated how Earth's plant life is likely to react over the next three centuries as Earth's climate changes in response to rising levels of human-produced greenhouse gases. Study results are published in the journal Climatic Change.

The model projections paint a portrait of increasing ecological change and stress in Earth's biosphere, with many plant and animal species facing increasing competition for survival, as well as significant species turnover, as some species invade areas occupied by other species.

Most of Earth's land that is not covered by ice or desert is projected to undergo at least a 30 percent change in plant cover - changes that will require humans and animals to adapt and often relocate.

In addition to altering plant communities, the study predicts climate change will disrupt the ecological balance between interdependent and often endangered plant and animal species, reduce biodiversity and adversely affect Earth's water, energy, carbon and other element cycles.

"For more than 25 years, scientists have warned of the dangers of human-induced climate change," said Jon Bergengren, a scientist who led the study while a postdoctoral scholar at Caltech.

"Our study introduces a new view of climate change, exploring the ecological implications of a few degrees of global warming. While warnings of melting glaciers, rising sea levels and other environmental changes are illustrative and important, ultimately, it's the ecological consequences that matter most."

When faced with climate change, plant species often must "migrate" over multiple generations, as they can only survive, compete and reproduce within the range of climates to which they are evolutionarily and physiologically adapted.

While Earth's plants and animals have evolved to migrate in response to seasonal environmental changes and to even larger transitions, such as the end of the last ice age, they often are not equipped to keep up with the rapidity of modern climate changes that are currently taking place.

Human activities, such as agriculture and urbanization, are increasingly destroying Earth's natural habitats, and frequently block plants and animals from successfully migrating.

More at the linkBy 2100, global climate change will modify plant communities covering almost half of... more

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14 days ago
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It’s All Trash

The other night, I took out my trash. As I placed it on the tree lawn, I started to... more

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Oceans have acidified more in the last 200 years than the previous 21,000 years

Man-made carbon emissions have acidified the world's oceans far beyond their natural levels, new research suggests.

In some regions, acidity levels rose faster in the last two centuries than it did in the previous 21,000 years, a study from the University of Hawaii has shown. Ocean acidity makes it harder for organisms such as molluscs and coral to construct the protective layers they need to survive.

Measuring changes in ocean acidity is difficult because it varies naturally between seasons, years and regions. Scientists looked at changes in the saturation level of aragonite, a form of calcium carbonate used to measure ocean acidification.

As seawater acidity rises, the saturation level of aragonite falls. Direct observations only date back 30 years, which is not long enough to reveal a meaningful trend. However the new research used simulations of ocean and climate conditions going back 21,000 years to the Last Glacial Maximum and forward in time to the end of the 21st century.

In several key coral reef regions aragonite saturation is already five times below its lowest pre-industrial range, according to the model. This translates to a decrease in overall calcification rates of corals and other shell-forming organisms of 15%, scientists at the university believe.

They fear calcification rates of some marine organisms could drop by more than 40% of their pre-industrial levels within the next 90 years.

Dr Tobias Friedrich, from the University of Hawaii, who led the study published in the journal Nature Climate Change, said: 'Any significant drop below the minimum level of aragonite to which the organisms have been exposed to for thousands of years and have successfully adapted will very likely stress them and their associated ecosystems.

'In some regions, the man-made rate of change in ocean acidity since the industrial revolution is 100 times greater than the natural rate of change between the Last Glacial Maximum and pre-industrial times.'

He added: 'When Earth started to warm 17,000 years ago, terminating the last glacial period, atmospheric CO2 (carbon dioxide) levels rose from 190 parts per million (ppm) to 280 ppm over 6,000 years.

'Marine ecosystems had ample time to adjust. Now, for a similar rise in CO2 concentration to the present level of 392 ppm, the adjustment time is reduced to only 100 - 200 years.'
Co-author Professor Axel Timmermann, also from the University of Hawaii, said: 'Our results suggest that severe reductions are likely to occur in coral reef diversity, structural complexity and resilience by the middle of this century.'

Read more: http://www.dailymail.co.uk/sciencetech/article-2090253/Oceans-acidified-200-years-did-previous-21-000-years-claims-new-climate-change-research.html#ixzz1kJIObunQMan-made carbon emissions have acidified the world's oceans far beyond their... more

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18 days ago
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Worldwide Hippies News Briefs Tuesday

UK scientists find ‘lost’ Darwin fossils Wikipedia to be blacked out over... more

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U.S. scientists link mass death of british bees to farm pesticides

Nicotine-based pesticides in widespread use by farmers are implicated in the mass... more

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25 days ago
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Seen A Gay Or Pro-Choice Bee Lately?

Recently Driving through persimmon and agarita embellished limestone and granite hills... more

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29 days ago
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Is Your City "Smart" Enough?

article is generally about Indian cities - question asks if they are "green"... more

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29 days ago
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Monsanto's drought resistant BT corn is a FAILURE- no more effective than non GMO

Failed "Drought Tolerant" GMO Corn Won't Help Farmers! The US... more

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1 month ago
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US billionaires interfere with Canada's Northern Gateway pipeline

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Dead Blackbirds Fall From the Sky Again in Beebe, Arkansas, on New Year’s Eve

Dozens of dead blackbirds have fallen from the sky over a small Arkansas town for the... more

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1 month ago
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Dead Cow Walking: The Case Against Born-Again Carnivorism

. The Atlantic . Dead Cow Walking: The Case Against Born-Again Carnivorism... more

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Views of melting Andean glaciers (Video)

- Various view of melting glaciers in the Andes mountains of Argentina and Chilean... more

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Saving planet: the “art” of recycling to rescuing wildlife

Artist Nina Nikiforova lives not far from the Black Sea shore and runs a small art... more

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Wales: A destination where sustainable living comes naturally

Sustainable ideas have been practiced here for centuries, with plenty of small-scale... more

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Protecting Land, Protecting Life

Water scarcity can lead to both drought and desertification as well as instigate... more

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Monsanto & Other BioTech Giants Deeply Entrenched In US Politics

– Monsanto, the multinational agricultural biotech giant, is also the... more

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