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December 21st 2009

Global Change in Harsh Environments Workshop - 9-11th of December 2009, Coyhaique, Chile
Texte par Sébastien Renard

Dr. Alex Fajardo and Dr. Frida Piper, of the Centro de Investigación en Ecosistemas de la Patagonia (CIEP), organized a workshop on Global Change in Harsh Environments at Coyhaique in Patagonia, Chile. The aim of this workshop was to get together researchers, international as well as South Americans and to create research interactions. It is commonly accepted that climate changes have an impact on ecosystems, but those effects are accentuated in harsh environment. The workshop was held in Coyhaique, in the North Patagonian part of Chile, where, as a reminder of the climate changing, we had an extraordinary weather for this habitually cold region. During this workshop, scientists working at different scales and in different harsh environments presented their research, results and further interrogations, which stimulated discussions during coffee breaks.

Patagonian Landscape

Chile, the “linear country” is a country of extreme conditions: from the Altiplano in the North with the Atacama Desert to La Tierra del Fuego in the south with its glacier fields, and the gradient of elevation with the high altitude environments in the Andes Mountains, Chilean ecosystems present a wide range of environmental gradients.

Dr. Patricio Aceituno, from Universidad de Chile and Humboldt Medal awarded, started the conference by presenting us the Chilean climate, strongly influenced by the ENSO (El Niño Southern Oscillation) and the Pacific Decadal Oscillation. He described us the climatic trends forecasted for Chile, recent evolutions the climate of the last century and some extreme climatic events of the 19th century. Dr. Thomas Kitzberger, from Universidad del Comahue in Argentina, presented us some effects of climate change on ecosystems key processes like tree demography and disturbance regime. Extreme droughts frequency cause massive mortality and can change forest composition. Also extreme warm drought allowing fires to spread to in non-fire evolved forests, like high elevation Nothofagus forests.

Part of the workshop was oriented on the ecophysiological limitations of plant in harsh environments, and Dr. Ana Sala from University of Montana presented some explanations of global changed induced tree mortality. She explained the physiological effect of drought on plants, like the cavitations effect. She highlighted that some fundamental mechanisms of plant physiology are still unknown such as the phloem physiology. The Andes Mountains are also a land of glacier, and the glacier reduction induced by the climate evolutions has been a great opportunity for Dr. Irene Garibotti, from Mendoza’s Instituto Argentino de Nivologia Glaciologia y Ciencias Ambiantales (IANIGLA) in Argentina, to study primary succession mechanisms and plant community in the Argentineans Mountains.

Harsh climate such as those found in the alpine environments of the high mountains of the Andes allowed Dr. Lohengrin Cavieres, from Universidad de Concepción Chile, to experiment on plant limitations and further develop the concept of facilitation, the positive interactions between species which is an important factor in plant ecology in those extreme environments.

Experiment device

Dr. Günter Hoch, from Basel University, Switzerland, presented us the Growth limitation hypothesis to explain the global phenomenon of climatic alpine treelines. From a global perspective, a striking similarity of the mean temperature of the growing season (6.4 ± 0.9°C) has been found in the upper treeline in mountain areas all over the world. Nonetheless, Dr. Hoch showed that there is still accumulation of carbon at the alpine treeline and therefore the growth reduction might be a sink limited phenomenon of plant physiology. Dr. Hoch reminded us that this hypothesis state for the cold climate boundary of treeline, as it exists a wide variety of treelines (due to drought, soil, topography…). To bring back the debate about treeline formation on the Chilean perspective, Dr. Alex Fajardo from CIEP, presented us his studies of the Nothofagus pumilio (Lenga) around Coyhaique, where he shows that drought can mask the growth limitation effect, indicating that local climatic factors can alter carbon balance. Dr. Fajardo is also interested in the mechanistic explanation of the change of plant life form at the treeline ecotone, from tree to shrub to low plants. The hypothesis is that the plant growth form, and thus the size, is coupled with the temperature near ground which is warmer.

In harsh environments, recruitment is a critical stage in ecosystems. Dr. Frida Piper, limitations from CIEP, is particularly interested in seedling physiology limitations. She presented her work on lenga seedlings using open top chambers to simulate an increase of temperature due to climate warming, which shows interesting results on interaction of warmer temperature and lower humidity.

Dr. Matthew Germino, from Idaho State University, presented his work on physiological limitation and treeline ecology in the Rocky Mountains of USA. His aim is to describe plant community dynamics at the upper treeline using physiological limitations. His work on seedling establishment and tree life forms showed that net thermal radiation and the radiation frost is critical for seedlings and that tree island formation is decisive in the treeline dynamics.

The alpine treeline dynamics in the Andes Mountains has been presented by Dr. Ana Srur, from IANIGLA in Argentina, where different trend are observed between north and south Patagonia forests, but generally growth seems to be partially correlated to spring and early summer temperature.

Finally, Dr. Bravo Leon from Universidad de Concepción, presented us the vascular plants of Antarctica (there is only 2 species), their adaptation to those extreme conditions like anti-freeze proteins preventing the clustering of ice crystals in the cells, and the effect of warming observed in the Antarctica Peninsula.

Npum Forest

Another objective of the workshop was to show us some Patagonians ecosystems. We went to the National reserve of Cerro Castillo to discover Nothofagus pumillo forests, some of Dr. Piper and Dr. Fajardo experiments, and enjoy the scenic landscapes of the Aysen region. After observing and discussing some experimentation, we appreciated a local meal, the famous “Lomo del poble”. In order to finish the trip with even more local flavour, Dr. Fajardo brought us to the local brewery of Dolbek, for a beer degustation.

Experiment device
This workshop was a great success, permitting to scientist from different countries and regions to confront their ideas and elaborate new research projects, all this in a convivial ambience. All this would not have been possible without Dr. Fajardo and D. Piper, the CIEP and also the help of the CONICYT and the Chile government. As a final word, I want to thank Dr. Eliot McIntire, whom, as he could not attend the workshop, gave me this great opportunity to participate to this event where I learned a lot and enjoyed the company of brilliant and really sympathetic researchers.

December 15th 2009

How remote-sensing is used to monitor forestry cover
Texte par Mélanie Desrochers

"Armed with vivid images from space and remote sensing data, scientists, environmentalists, and armchair conservationists are now tracking threats to the planet and making the information available to anyone with an Internet connection. " This is how a complete Yale 360 article on the subject of satellite use for forestry cover starts.

Landsat image revealing "fishbone" deforestation
along roads in the Brazilian Amazon

From tracking new biodiversity hotspots, assessing "real-time" deforestation in the Amazone, tracking threats to pristine rivers from hydroelectric projects, cataloguing endangered species, remote sensing has never been more "user friendly" through mostly free data access and Google Earth tool. "The spread of satellite technology — and related computer applications such as Google Earth — are changing the way scientists, conservationists, and ordinary citizens are monitoring the environment and communicating their findings to the public. " (Yale 360)

"The first launch of a non-weather satellite for civilian use occurred in 1972, when NASA put Landsat into orbit to monitor the planet’s landmasses, tracking everything from desertification to changes in agriculture. Since then, ever-more sophisticated satellites have used cameras and a variety of sensors — including passive microwave, which can penetrate clouds to image the earth’s surface, and infrared sensors that can measure temperatures — to monitor a host of physical processes." (Yale 360)

"Introduced in 2005, Google Earth — which can be downloaded for free — aggregates and organizes satellite imagery, aerial photography, and three-D global information system data from a range of sources and presents it in a format that is easily accessible to the general public. Many scientists have begun to adapt Google Earth technology to their research and their communications with the public. The technology also has emerged as an effective way to publish scientific results in an accessible and meaningful format. While Google Earth is not going to replace scientific journals, it offers a concise, visual format for presenting research that can be more compelling than data points on a chart, rows in a spreadsheet, or a 4-color map." (Yale 360)

Presently optical sensing can do a reasonably good job distinguishing between cleared forest and natural forest—assuming cloud cover is minimal, a big assumption in the tropics. It does less well identifying and distinguishing between recovering forests, selectively logged forest, tree plantations, and degraded forests. New active sensing technologies, like cloud-penetrating radar and LIDAR, may change this. Some of these technologies may allow scientists to directly measure biomass in dense forests—currently many sensing technologies are limited by their tendency to "saturate" at a threshold well below the actual biomass in such forests. (Mongabay1) Active sensing—which sends out pulses of energy and reads the radiation that bounces back to the sensor—can provide detailed information about Earth’s surface, including the structure of a forest or the distinction between secondary and primary forest. (Mongabay1)

This 3-D image shows an invasion (red-pink trees)
into a protected forest reserve (blue-green trees)
in lowland rainforest. (CAO)

At CEF-CFR, Benoit St-Onge is conducting a lot of challenging research on the use of LIDAR. Recently, all the Lake Duparquet Research and Teaching Forest (FERLD)  in Abitibi-Témiscamingue has been criss-crossed by plane to obtain a complete LIDAR cover. This one-meter resolution survey gives the opportunity to address questions at the tree scale!

"A new frontier for remote sensing is the emergence of REDD (Reducing Emissions from Deforestation and Degradation), a mechanism for compensating tropical countries for conserving their forests. To date, one of the biggest hurdles for the concept has been establishing credible national baselines for deforestation rates — in order to compensate countries for "avoided deforestation," officials must first know how much forest the country has been clearing on a historical basis. For the remote sensing community, REDD presents an opportunity to showcase the power of remote sensing and generate a source of funding for countries to improve their sensing capabilities." (Yale 360) | New Eyes in the Sky: Cloud Free Tropical Forest Monitoring for REDD 

Catherine Potvin and her lab colleagues, all CEF-CFR members, are helping the Panama government to identify actions to reduce and avoid deforestation (through the REDD mechanism). "The work carried out in cooperation with Panama indigenous groups focuses on conservation of plants used in a traditional way and on sustainable land uses", explains Dr. Potvin. A detail of her work on REDD can be found online .

"But researchers are using remote sensing of forests for more than monitoring forest loss. Greg Asner of the Carnegie Institution's Department of Global Ecology at Stanford University, has developed advanced applications for processing data generated by a wide range of sensors, including Carnegie’s state-of-the-art Airborne Observatory (CAO), which uses a combination of technologies aboard high-altitude aircraft to create high-resolution, three-dimensional maps of vegetation structure. These maps can be used to detect small changes in forest canopy structure from selective logging, measure biomass in dense tropical rainforests (presently limited due to “saturation” in carbon-dense ecosystems), and even distinguish between individual plant species, including invasive species. Asner’s group recently won grants from the Gordon and Betty Moore to expand upon CLASlite—a desktop monitoring application that enables conservationists anywhere to measure forest biomass and deforestation—and to develop its spectranomics project. This project has the potential to inventory biodiversity across 40,000 acres of rainforest per day by detecting the chemical and spectral (light-reflecting) properties of individual plant species across a diverse landscape. (Mongabay1)

Deforestation in Rondonia, Brazil, from 1975 to 2001.
Landsat images courtesy USGS.

Meanwhile, Holly Gibbs, a researcher at Stanford University, recently used remote sensing data to evaluate shifting patterns of tropical deforestation. She found that 80 percent of agricultural expansion since the 1980s came at the expense of forests. “I recently analyzed the Landsat database created by the UN FAO to estimate the probable land sources for expanding croplands,” she told mongabay.com. “I was also able to consider changing patterns of agricultural expansion during the 1980s and 1990s and demonstrate that the amount of cropland expanding into forested areas, rather than grassland or previously disturbed forests, is increasing. Documenting changing patterns in land use is becoming increasingly important as we see mounting demands for global food, feed, and fuel, highlighting the importance of continuing the longtime history of Landsat into coming decades.” (Mongabay1)

Deforestation data from INPE

Gibbs says increased accessibility has been key to wider use of satellite data. “Satellite data is becoming increasingly accessible to everyone from a local park ranger to scientists at major universities, opening the door to more diverse analyses,” she said. “The creation of ‘free’ global Landsat mosaics, for example, is a major push for initiatives to Reduce Emissions from Deforestation and Degradation [REDD] across the tropics that rely on what used to be very costly data.” (Mongabay1)

A review of different approaches to Mapping and monitoring carbon stocks with satellite observations has been published by Goetz et al. 2009 .

References & Links

May 4th 2009

Summer course at CEF : Functionnal traits on plants
Gault natural Reserve , Mont St-Hilaire
Text by Samuel Royer-Tardif, pictures Sophie Brugerolle

It was in the magnificent forest of Mont St-Hilaire, in the Gault natural reserve , that, from April 26th to 29th, thirty students from the CEF and abroad had the chance to follow the new CEF summer course on plant functional traits developed and supervised by Alison Munson (Laval University)

Éric Garnier

For the occasion, four of the most reputed scientists working in that field were invited:

Peter Reich
A series of talks on relationships among plant traits, their importance in community assembly and their consequences on ecosystem functioning were delivered to knowledge-thirsty students. Other guests contributed also to the excellent formation:

In this entertaining atmosphere, students had the opportunity to share great discussions on their research and their vision of ecology with the different guests. The comfortable temperature allowed many to climb to the mountain top while others took advantage of the occasion to hike the many trails and observe the plant and animal diversity and integrate freshly acquired notions. Overall, this activity was a clear success and an experience to repeat. We dearly thank everyone who contributed.

From Alison
I think I can speak for all the profs of the Traits course in saying that we really appreciated the group of students involved in this course and the numerous formal and less formal interactions during this intensive course (intensive being the key word). We had students at all levels involved – from MSc to finishing postdocs – and everyone exchanged either during the classes, on the trail, around the fire (without burning more of the forest, I’m sure Martin is relieved), or with a Frisbee. Thanks to all for their contributions AND to Sophie Brugerolle for logistics, coordination and social glue.

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La référence vedette !

Jérémie Alluard (2016) Les statistiques au moments de la rédaction 

  • Ce document a pour but de guider les étudiants à intégrer de manière appropriée une analyse statistique dans leur rapport de recherche.

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