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Plants Migrate Uphill at Temperatures Rise, French Study Says
By Alex Morales
<!-- WARNING: #foreach: $wnstory.ATTS: null at /bb/data/web/templates/webmacro_en/washingtonstory.wm:266.2 --> <!-- WARNING: #foreach: $wnstory.ATTS: null at /bb/data/web/templates/webmacro_en/washingtonstory.wm:280.19 --> June 26 (Bloomberg) -- Dozens of common plant species in France are being discovered at higher elevations as temperatures rise, indicating global warming is already affecting a wide range of ecosystems.
The findings stem from a survey of 171 plants led by Jonathan Lenoir, a doctoral student at AgroParisTech, a Paris- based environmental research institute. The flora, from ferns and grasses to shrubs and trees, seeded about 29 meters (95 feet) higher each decade during the periods examined, the team said today in the journal Science.
``This is the first time that it is shown that climate change has already implied a significant effect on a large set of plant species under a wide range of temperature conditions in the last century,'' Lenoir said in a June 24 telephone interview from Nancy, France, where AgroParisTech has a branch.
Man-made global warming can alter ecosystems and food chains because species react to higher temperatures at different rates, affecting the interaction between plants and animals. A hotter climate can also rule out some areas from growing certain crops, and make other regions easier to cultivate.
Research by three U.S. universities published yesterday said plants in California may need to migrate a mile (1.6 kilometers) a year into cooler or wetter areas to survive. A study last June showed Arctic heather is flowering three weeks sooner than a decade ago as conditions warm earlier in the year.
Wine-growers including Miguel Torres, the eponymous head of Spain's largest family-owned winemaker, told Bloomberg last year that grapevine cultivation belts are moving north and uphill as the climate heats up.
`Important' Analysis
Lenoir's study focused on species found in forests so that the impact of warming could be more easily separated from other factors, such as land-use change. He said the findings aren't applicable to agriculture. The researchers concentrated on forest plants in six French mountain ranges, from sea-level to an altitude of 2,600 meters, covering a wide range of climates.
``The study is important because most focus has been on what goes on at the extremes, like the Arctic, or the most extreme climates,'' Jens-Christian Svenning, associate professor of biology at the University of Aarhus in Denmark, said in a June 24 telephone interview. ``It's important also to document what's really happening in less extreme situations and closer to the center of species distributions.''
Svenning, who investigates how plants respond to changes in the climate, wasn't involved in Lenoir's research and hadn't read the full paper.
Food Chain `Dismantled'
Lenoir's team, which also included scientists at the Pontificia Catholic University in Santiago, Chile, examined data from 28,000 historical surveys and filtered out rare species and those with insufficient data.
Trees and shrubs were found to shift less than plants such as mosses, ferns and herbs, which have shorter life-spans. Species confined to mountainous areas were also observed to move more than ubiquitous plants found across the full range of altitudes.
``Tree species are expected to be more threatened by current warming than grasses,'' Lenoir said. ``This may imply profound changes in the composition and structure of plant communities in forests. You might change the connection between plant-species communities and the animals that interact with them.
``The whole food chain is dismantled,'' Lenoir said. ``Plant species are the base of food webs, so it's really important to know about plant species in a warming climate.''
`Urgent' Study Needed
While results can be broken down into groups of species such as trees or grasses, it isn't useful to discuss individual plants because there's a greater chance of anomalies, Lenoir said.
The researchers used temperature data from Meteo-France, the government forecaster, and found that for the six mountain regions studied, the 20 years from 1986 to 2005 were typically hotter than the long-term average, while the two decades preceding that were cooler. They used this to split the plant samples into two distinct periods: 1905 to 1985, during which the mean year of the surveys was 1971, and 1986 to 2005, during which the average of the study years was 1993.
The scientists focused on the ``optimal elevation,'' where forest plants were most likely to be found, rather than the extremes of altitude where they occasionally reach. More than two thirds of plants -- 118 of the 171 species examined -- moved uphill from 1971 to 1993, with 53 moving downhill. Overall, the average height gain was ``statistically significant,'' they wrote, amounting to 64.8 meters, or 29.4 meters per decade.
The researchers wrote that further studies are ``urgently needed'' do work out the magnitude and consequences of changes that are taking place.
``Climate warming is a driving force that acts at a worldwide scale,'' Lenoir said. ``We need more and more long- term and large-scale multi-species monitoring databases.''
To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net .
Last Updated: June 26, 2008 14:00 EDT
http://www.bloomberg.com/apps/news?pid=washingtonstory&sid=aGJrg9eiPtT4
By Alex Morales
<!-- WARNING: #foreach: $wnstory.ATTS: null at /bb/data/web/templates/webmacro_en/washingtonstory.wm:266.2 --> <!-- WARNING: #foreach: $wnstory.ATTS: null at /bb/data/web/templates/webmacro_en/washingtonstory.wm:280.19 --> June 26 (Bloomberg) -- Dozens of common plant species in France are being discovered at higher elevations as temperatures rise, indicating global warming is already affecting a wide range of ecosystems.
The findings stem from a survey of 171 plants led by Jonathan Lenoir, a doctoral student at AgroParisTech, a Paris- based environmental research institute. The flora, from ferns and grasses to shrubs and trees, seeded about 29 meters (95 feet) higher each decade during the periods examined, the team said today in the journal Science.
``This is the first time that it is shown that climate change has already implied a significant effect on a large set of plant species under a wide range of temperature conditions in the last century,'' Lenoir said in a June 24 telephone interview from Nancy, France, where AgroParisTech has a branch.
Man-made global warming can alter ecosystems and food chains because species react to higher temperatures at different rates, affecting the interaction between plants and animals. A hotter climate can also rule out some areas from growing certain crops, and make other regions easier to cultivate.
Research by three U.S. universities published yesterday said plants in California may need to migrate a mile (1.6 kilometers) a year into cooler or wetter areas to survive. A study last June showed Arctic heather is flowering three weeks sooner than a decade ago as conditions warm earlier in the year.
Wine-growers including Miguel Torres, the eponymous head of Spain's largest family-owned winemaker, told Bloomberg last year that grapevine cultivation belts are moving north and uphill as the climate heats up.
`Important' Analysis
Lenoir's study focused on species found in forests so that the impact of warming could be more easily separated from other factors, such as land-use change. He said the findings aren't applicable to agriculture. The researchers concentrated on forest plants in six French mountain ranges, from sea-level to an altitude of 2,600 meters, covering a wide range of climates.
``The study is important because most focus has been on what goes on at the extremes, like the Arctic, or the most extreme climates,'' Jens-Christian Svenning, associate professor of biology at the University of Aarhus in Denmark, said in a June 24 telephone interview. ``It's important also to document what's really happening in less extreme situations and closer to the center of species distributions.''
Svenning, who investigates how plants respond to changes in the climate, wasn't involved in Lenoir's research and hadn't read the full paper.
Food Chain `Dismantled'
Lenoir's team, which also included scientists at the Pontificia Catholic University in Santiago, Chile, examined data from 28,000 historical surveys and filtered out rare species and those with insufficient data.
Trees and shrubs were found to shift less than plants such as mosses, ferns and herbs, which have shorter life-spans. Species confined to mountainous areas were also observed to move more than ubiquitous plants found across the full range of altitudes.
``Tree species are expected to be more threatened by current warming than grasses,'' Lenoir said. ``This may imply profound changes in the composition and structure of plant communities in forests. You might change the connection between plant-species communities and the animals that interact with them.
``The whole food chain is dismantled,'' Lenoir said. ``Plant species are the base of food webs, so it's really important to know about plant species in a warming climate.''
`Urgent' Study Needed
While results can be broken down into groups of species such as trees or grasses, it isn't useful to discuss individual plants because there's a greater chance of anomalies, Lenoir said.
The researchers used temperature data from Meteo-France, the government forecaster, and found that for the six mountain regions studied, the 20 years from 1986 to 2005 were typically hotter than the long-term average, while the two decades preceding that were cooler. They used this to split the plant samples into two distinct periods: 1905 to 1985, during which the mean year of the surveys was 1971, and 1986 to 2005, during which the average of the study years was 1993.
The scientists focused on the ``optimal elevation,'' where forest plants were most likely to be found, rather than the extremes of altitude where they occasionally reach. More than two thirds of plants -- 118 of the 171 species examined -- moved uphill from 1971 to 1993, with 53 moving downhill. Overall, the average height gain was ``statistically significant,'' they wrote, amounting to 64.8 meters, or 29.4 meters per decade.
The researchers wrote that further studies are ``urgently needed'' do work out the magnitude and consequences of changes that are taking place.
``Climate warming is a driving force that acts at a worldwide scale,'' Lenoir said. ``We need more and more long- term and large-scale multi-species monitoring databases.''
To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net .
Last Updated: June 26, 2008 14:00 EDT
http://www.bloomberg.com/apps/news?pid=washingtonstory&sid=aGJrg9eiPtT4
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