Scientists from Mexico, Canada and the United States are now working toward a regional framework to facilitate LTER research and collaboration across the North American continent.
The August 1999 ESA annual meeting in Spokane served as the venue for an all-day, public workshop, which offered an opportunity to North American Regional ecologists to explain their research and the related issues they are addressing.
The national chairs of the networks, James Gosz (U.S. LTER), Hague Vaughan (Environmental Monitoring and Assessment Network, Canada) and Gerardo Ceballos (National Autonomous University of Mexico), introduced the history, structure and policy that drive their networks. Following the presentations, scientists described current cross-site research, including the fifteen-year-long collaborative hydrological modeling project, which involves scientists at Coweeta (U.S.) and Chamela (Mexico) field stations.
In summary, communication and international interactions, science-driven questions and comparisons, opportunities for data sharing, common experiments, monitoring, and joint meetings are some of the issues driving the regional network effort.
At a planning meeting followed the workshop on Wednesday 11 August, NAR representatives discussed numerous potential collaborations, focusing on continental-scale projects in a round-table discussion format.
Topping the list of topics, the Global Terrestrial Observing System will form a global network of validation sites for remotely acquired imagery. GTOS will produce many significant products, including global net primary productivity (NPP) estimations for various ecosystem types.
The imagery will be acquired using a Moderate Resolution Imaging Spectro-radiometer (MODIS)—the key instrument aboard the Terra (EOS AM-1) satellite, now in operation. The MODIS instrument will view the Earth’s entire surface every few days, acquiring data in 36 spectral bands. These data will improve the understanding of global dynamics and processes occurring on the surface of the Earth, in the oceans, and in the lower atmosphere. North American Region ecologists can provide much-needed validation information for land cover and leaf-area index (LAI). The information will then be synthesized with a project that will estimate net primary productivity for various land-cover types across the globe. Validation over broad spatial scales will improve the GTOS system as a whole. Each individual site is important for calibrating the system for the entire continent.
EMAN-representative Hague Vaughan expressed interest in exchanging validation information for NASA data access as "Canadian remote sensing data is too expensive for ecological research to afford" Vaughan said. The new satellite system (Terra) offers frequent updates and results in rapid turnaround for examining changes in land cover and land use.
Other themes within GTOS include Global Observation of Forest Cover (GOFC), the Terrestrial Carbon Cycle Initiative (in preparation), and in the year 2005, the need to determine a country’s carbon budget under the Kyoto Protocol. (For more information, see the GT NET-NPP demonstration project in the Spring 1998 issue of the LTER Network Newsletter.
The NAR Network may be instrumental in identifying the carbon budgets of countries in relation to the Kyoto Protocol (a.k.a. The UN Framework Convention on Climate Change).
"Scientists are not used to thinking at kilometer-to-100-km scales, but we must learn to think bigger – far beyond the normal realm of our science."
Jim Gosz, Chair, ILTER Network
On 10 December 1997, 160 nations reached an historic agreement in Kyoto, Japan on limiting emissions of carbon dioxide and other "greenhouse gases." The Kyoto Protocol calls for the industrialized nations to reduce their average national emissions over the period 2008-2012 to about five percent below 1990 levels, creating the need to quantify what 1990 carbon density was, and to track how much carbon dioxide is being sequestered and released from each country.
Determining various countries’ vegetation cover types becomes important to determining a carbon budget, and emphasizes the need for networks of ecologists who understand the carbon budgets of their sites. Canada and the United States signed the agreement in 1997. As a "developing country," Mexico is exempt from any restrictions on CO2 production, but may figure into a program for international trading of greenhouse gas emissions, for which Mexico’s ecologists will need to understand the carbon density of its ecosystems as well.
All of these projects rely on accurate land classification products. "Up until now," said Jim Gosz, chair of the International LTER Network, "such products have been sketchy and of little value to ecologists."
Historically, IGBP classifications have been based on life characteristics and are fairly general. NASA believes its products are "true" but ecologists have found that reality varies greatly from this "truth" in some cases.
"For example," Gosz said, "at the Sevilleta LTER Site in New Mexico, a grassland was misclassified as shrubland," a large discrepancy that was identified by Sevilleta ecologists. International networks of ecologists can help improve land-cover classifications through ground-truthing and other cooperative exercises. Sites that participate in validation projects are entitled to NPP products such as one-km imagery of NPP, NEP, one-km imagery of land cover, LAI 500-m imagery NDVI, and 250-m imagery NDVI.
FLUXNET is another project that may flourish through a regional network of ecologists. FLUXNET integrates long-term, worldwide CO2 flux measurements of carbon dioxide, water vapor, and energy exchange from a variety of worldwide ecosystems into consistent, quality assured, documented datasets. This and other increasingly important technologies require knowledge of ecosystems at broad spatial scales, increasing the scale at which validation occurs.
MEX-LTER representative Manuel Maass expressed an interest in developing an exchange of ecological expertise across borders. "We would like to begin a system for technology transfer, in which graduate students or post-docs with needed skills would work in ecosystems in one of the other NAR countries," Maass said. These and other projects will take shape at the All Scientists Meeting August 2000, Snowbird, Utah (see http://www.lternet.edu/network/meetings/allsci/2000/).
