Tag Archives: Vegetation

Rockies flora show climate impact

FOR IMMEDIATE RELEASE An intensive study of the flora of one meadow in the Rocky Mountains of Colorado over nearly 40 years reveals a widespread and consistent pattern of climate-induced change. LONDON, 19 March – Two thirds of alpine flowers have changed their pattern of bloom in response to climate change. Half of them have begun to bloom weeks earlier than normal, one third are reaching their peak bloom well ahead of the traditional almanac date, and others are producing their last blooms later in the year. The season of flowers – that feast for bees and butterflies, and a signal for insectivorous birds to make the most of their moment in the sun – is a month longer than it was four decades ago. This conclusion comes with two qualifications. The first is that it is limited to one meadow in one location in Colorado’s Rocky Mountains in the US. But the other is that it is the product of a meticulous, painstaking 39-year-long study by one researcher. So it follows that since there is not much room for mistake or argument about the pattern in one well-studied location, then a similar pattern probably does apply in many upland temperate zone sites. When David Inouye of the University of Maryland began his research, he was a graduate student who just wanted to know what sources of nectar were available for hummingbirds and bumble bees. So he started counting flowers about 3,000 metres above sea level in Crested Butte, Colorado, at the Rocky Mountain Biological Laboratory. And he carried on.

Big picture

He and colleagues report in the Proceedings of the National Academy of Sciences that they chose 60 common wildflower species – most of them perennial herbs – and they specifically excluded the rarer species because there was not enough data. So they made their judgement on the basis of two million flower counts, during the 39-year interval in which summer air temperatures increased by about 0.4°C per decade and in which the spring snow melt advanced by about 3.5 days per decade. And they also specifically looked at the entire pattern of spring and summer bloom: the big picture of what biologists call phenology, the timing of biological events, in one place. “Most studies rely on first dates like flowering or migration, because they use historical data sets that were not intended as scientific studies”, said Professor Inouye. “First flowering is easy to observe. You don’t have to take the time to count the flowers. So that’s often the only information available. It has taken a lot of effort to get the comprehensive insights needed for this analysis which helps us understand how ecological communities are going to change in the future.” Biologists around the world have begun to use phenological shifts as indicators of climate, and as a basis for future conservation plans, and all of them have observed a pattern of change.

Consistent findings

European researchers confirmed that plants were either moving to higher latitudes, or blooming earlier in response to global warming, and that birds, butterflies and blossoms were actually heading to higher altitudes. Some have used historic observations by one of America’s literary giants as the basis for their research into climate change, and others have looked at the consequences of changes in the plant timetable for the grazers and predators that depend on specific plant communities. But Inouye and colleagues now think that much of the phenological evidence so far has underestimated the numbers of species that have altered their flowering times, and probably overestimated the magnitude of change: what matters in the field or the meadow is the sum of all the changes, and not just the first dates of flowering. Inouye and students divided the meadow into 30 plots, and counted flowers every other day for 39 years, for five months every year. So because of the initial basis of the research, continued for so many years, the scientists had sure data on changes for individual species, including the first flowering, the peak flowering and the last blooms, along with a measure of changes in abundance. The date of first flowering has advanced by six days per decade, the spring peak is on average five days earlier per decade, and the last flower of autumn has been three days later every decade. – Climate News Network

FOR IMMEDIATE RELEASE An intensive study of the flora of one meadow in the Rocky Mountains of Colorado over nearly 40 years reveals a widespread and consistent pattern of climate-induced change. LONDON, 19 March – Two thirds of alpine flowers have changed their pattern of bloom in response to climate change. Half of them have begun to bloom weeks earlier than normal, one third are reaching their peak bloom well ahead of the traditional almanac date, and others are producing their last blooms later in the year. The season of flowers – that feast for bees and butterflies, and a signal for insectivorous birds to make the most of their moment in the sun – is a month longer than it was four decades ago. This conclusion comes with two qualifications. The first is that it is limited to one meadow in one location in Colorado’s Rocky Mountains in the US. But the other is that it is the product of a meticulous, painstaking 39-year-long study by one researcher. So it follows that since there is not much room for mistake or argument about the pattern in one well-studied location, then a similar pattern probably does apply in many upland temperate zone sites. When David Inouye of the University of Maryland began his research, he was a graduate student who just wanted to know what sources of nectar were available for hummingbirds and bumble bees. So he started counting flowers about 3,000 metres above sea level in Crested Butte, Colorado, at the Rocky Mountain Biological Laboratory. And he carried on.

Big picture

He and colleagues report in the Proceedings of the National Academy of Sciences that they chose 60 common wildflower species – most of them perennial herbs – and they specifically excluded the rarer species because there was not enough data. So they made their judgement on the basis of two million flower counts, during the 39-year interval in which summer air temperatures increased by about 0.4°C per decade and in which the spring snow melt advanced by about 3.5 days per decade. And they also specifically looked at the entire pattern of spring and summer bloom: the big picture of what biologists call phenology, the timing of biological events, in one place. “Most studies rely on first dates like flowering or migration, because they use historical data sets that were not intended as scientific studies”, said Professor Inouye. “First flowering is easy to observe. You don’t have to take the time to count the flowers. So that’s often the only information available. It has taken a lot of effort to get the comprehensive insights needed for this analysis which helps us understand how ecological communities are going to change in the future.” Biologists around the world have begun to use phenological shifts as indicators of climate, and as a basis for future conservation plans, and all of them have observed a pattern of change.

Consistent findings

European researchers confirmed that plants were either moving to higher latitudes, or blooming earlier in response to global warming, and that birds, butterflies and blossoms were actually heading to higher altitudes. Some have used historic observations by one of America’s literary giants as the basis for their research into climate change, and others have looked at the consequences of changes in the plant timetable for the grazers and predators that depend on specific plant communities. But Inouye and colleagues now think that much of the phenological evidence so far has underestimated the numbers of species that have altered their flowering times, and probably overestimated the magnitude of change: what matters in the field or the meadow is the sum of all the changes, and not just the first dates of flowering. Inouye and students divided the meadow into 30 plots, and counted flowers every other day for 39 years, for five months every year. So because of the initial basis of the research, continued for so many years, the scientists had sure data on changes for individual species, including the first flowering, the peak flowering and the last blooms, along with a measure of changes in abundance. The date of first flowering has advanced by six days per decade, the spring peak is on average five days earlier per decade, and the last flower of autumn has been three days later every decade. – Climate News Network

Fungus governs soil's carbon content

FOR IMMEDIATE RELEASE
The soil stores the greater part of the Earth’s carbon. Just how much it stores is determined largely by what sort of fungi live in the roots of plants and trees, researchers have found.

LONDON, 28 January – Most of the planet’s carbon is neither in the forests nor the atmosphere. It is in the soil under your feet. US scientists think that they have identified the mechanism that keeps most of this awesome treasury of carbon locked away in the soil – or surrenders much more of it back to the atmosphere. The answer is: a fungus.

This answer matters because what happens to soil carbon is critical to predicting the planet’s future climate, according to Colin Averill of the University of Texas at Austin.

He and colleagues from the Smithsonian Tropical Research Institute in Panama and Boston University in Massachusetts report in Nature that the storage of carbon in soils is influenced by the mycorrhizal fungi that live in symbiotic relationships with plants.

In a symbiotic relationship, creatures benefit from each other, and in this case the fungi extract nitrogen from the soil, and make it available to the roots of the growing plant. Plants take carbon from the air to make their tissues; when a tree falls, or a branch breaks, or a shrub dies, most of the carbon gets back into the atmosphere through decomposition. But some gets buried, and stays in the soil

Averill and colleagues decided to look at the respective roles of two kinds of mycorrhizal fungus: one group known as ecto- and ericoid mycorrhiza (EEM), and another called arbuscular mycorrhiza (AM). The first produce enzymes that degrade nitrogen.

Out-competing microbes

That means that whenever there is organic nitrogen in the soil, the fungi take the greater share: they compete with soil microbes for the soil nutrients.  So the scientists predicted that if the EEM type was dominant, then there would be greater proportions of carbon conserved in the soil.

They then looked at all the known data about soil carbon and nitrogen in various ecosystems: the boreal forests of the north; the temperate woodlands, the tropical forests and the grasslands.

Where the proportions of arbuscular mycorrhiza were highest, the levels of soil carbon tended to be lower. In an EEM world, there could be 70% more carbon stored in the soil. Unexpectedly, they found that the relationship was independent of, and mattered far more than, the effects of net primary production, temperature, rainfall and levels of soil clay. What mattered most was the type of fungus dwelling in the roots of the forest trees, or the savannah grasses.

“Natural fluxes of carbon between the land and atmosphere are enormous and play a crucial role in regulating the concentration of carbon dioxide in the atmosphere and in turn, the Earth’s climate”, said Averill.

“This analysis clearly establishes that the different types of symbiotic fungi exert major control on the global carbon cycle, which has not been fully appreciated or demonstrated until now.”

Complex relationships

The research, once again, is a reminder that climate models depend on an understanding of how the world works, and that there is still much more to understand about planetary workings. Fungi are mostly invisible. Ceps, morels, chanterelles, truffles and field mushrooms are edible prizes that pop up from the soil, but most of the fungal action is below the soil.

The biggest single creature on the planet is not the blue whale but a fungus that covers 10 square kilometers of soil in the Blue Mountains of Oregon, in the US.

The research is a reminder of a secret kingdom buried in the first metre or so of the world’s soils, a kingdom with profound influence on the machinery of the planetary carbon cycle.

“The research is not only relevant to models and predictions of future concentrations of atmospheric greenhouse gases, but also challenges the core foundation in modern biogeochemistry that climate exerts major control over soil carbon pools,” said Adrien Finzi, of Boston University, one of the authors. – Climate News Network

FOR IMMEDIATE RELEASE
The soil stores the greater part of the Earth’s carbon. Just how much it stores is determined largely by what sort of fungi live in the roots of plants and trees, researchers have found.

LONDON, 28 January – Most of the planet’s carbon is neither in the forests nor the atmosphere. It is in the soil under your feet. US scientists think that they have identified the mechanism that keeps most of this awesome treasury of carbon locked away in the soil – or surrenders much more of it back to the atmosphere. The answer is: a fungus.

This answer matters because what happens to soil carbon is critical to predicting the planet’s future climate, according to Colin Averill of the University of Texas at Austin.

He and colleagues from the Smithsonian Tropical Research Institute in Panama and Boston University in Massachusetts report in Nature that the storage of carbon in soils is influenced by the mycorrhizal fungi that live in symbiotic relationships with plants.

In a symbiotic relationship, creatures benefit from each other, and in this case the fungi extract nitrogen from the soil, and make it available to the roots of the growing plant. Plants take carbon from the air to make their tissues; when a tree falls, or a branch breaks, or a shrub dies, most of the carbon gets back into the atmosphere through decomposition. But some gets buried, and stays in the soil

Averill and colleagues decided to look at the respective roles of two kinds of mycorrhizal fungus: one group known as ecto- and ericoid mycorrhiza (EEM), and another called arbuscular mycorrhiza (AM). The first produce enzymes that degrade nitrogen.

Out-competing microbes

That means that whenever there is organic nitrogen in the soil, the fungi take the greater share: they compete with soil microbes for the soil nutrients.  So the scientists predicted that if the EEM type was dominant, then there would be greater proportions of carbon conserved in the soil.

They then looked at all the known data about soil carbon and nitrogen in various ecosystems: the boreal forests of the north; the temperate woodlands, the tropical forests and the grasslands.

Where the proportions of arbuscular mycorrhiza were highest, the levels of soil carbon tended to be lower. In an EEM world, there could be 70% more carbon stored in the soil. Unexpectedly, they found that the relationship was independent of, and mattered far more than, the effects of net primary production, temperature, rainfall and levels of soil clay. What mattered most was the type of fungus dwelling in the roots of the forest trees, or the savannah grasses.

“Natural fluxes of carbon between the land and atmosphere are enormous and play a crucial role in regulating the concentration of carbon dioxide in the atmosphere and in turn, the Earth’s climate”, said Averill.

“This analysis clearly establishes that the different types of symbiotic fungi exert major control on the global carbon cycle, which has not been fully appreciated or demonstrated until now.”

Complex relationships

The research, once again, is a reminder that climate models depend on an understanding of how the world works, and that there is still much more to understand about planetary workings. Fungi are mostly invisible. Ceps, morels, chanterelles, truffles and field mushrooms are edible prizes that pop up from the soil, but most of the fungal action is below the soil.

The biggest single creature on the planet is not the blue whale but a fungus that covers 10 square kilometers of soil in the Blue Mountains of Oregon, in the US.

The research is a reminder of a secret kingdom buried in the first metre or so of the world’s soils, a kingdom with profound influence on the machinery of the planetary carbon cycle.

“The research is not only relevant to models and predictions of future concentrations of atmospheric greenhouse gases, but also challenges the core foundation in modern biogeochemistry that climate exerts major control over soil carbon pools,” said Adrien Finzi, of Boston University, one of the authors. – Climate News Network