AIRSAR Campaign in Central America Helps Conservation Science

Central America and Southern Mexico (Meso America) are highly diverse biological regions containing a variety of tropical forest life zones that range from lowland dry and wet forests to mountain rain and cloud forests and coastal wetlands. Historically, this environment has been changing as a result of numerous natural and human-induced effects, particularly in the past few decades. The region's deforestation rate is second only to the Amazon basin. Recent studies in Guatemala report forest clearing rates of greater than 3 percent per year and nearly 5 percent per year in the Maya Biosphere buffer zone and agricultural zone south of the reserve, respectively. With increasing forest clearing and logging, the region has been loosing its biological and cultural diversity and resources at a much faster rate than before.

Several characteristics of the regional landscape have also made Central America one of the most environmentally vulnerable regions of the world. The region lies between the Pacific and Atlantic oceans and is susceptible to impacts of seasonal storms and hurricanes from both sides. With its mountainous terrain and complex river basin systems, landslides and flooding are common throughout the region. These hazards are also exacerbated by recent extreme weather events, such as those resulting from the El Niņo Southern Oscillation phenomenon, which periodically affects the region. El Nino Southern Oscillation -related changes in regional rainfall patterns lead to droughts and wildfires, or intensive rains, landslides and floods. There have been five El Niņo events since 1982, and three of them have occurred in the 1990s. The 1997-1998 El Niņo was significant, and set the stage for the disastrous floods and landslides that occurred as a result of Hurricane Mitch.

A large area of Central America within the lowland forests and coastal regions is covered by wetlands and floodplains. These wetland systems are important for recycling water in regional and global hydrological processes. They provide surface water resources in the region, and are habitats for a large number of tropical flora and fauna. These systems are extremely vulnerable to climate change and variability as a result of changes in rainfall patterns and severe drought and flooding events. The large extent of coastal ecosystems, including the coastal wetlands and freshwater marshes, and enormous wealth of surface and groundwater resources, provide many goods and services to the residents and communities of Central America. Freshwater marshes and wetlands have been a historical source of water for agricultural and land use activities and are believed to be important to help identify cultural and archeological sites in the region.

These natural and human-induced threats to the environment have also degraded the biological diversity and increased the threat to historical and archeological sites. Identifying the extent of these impacts and quantifying the intensity of disturbances on the regional environment, both in its natural and cultural resources, are main concerns of environmental and conservation groups. In recent years, numerous aid organizations and government agencies, including NASA, have increased their efforts to provide resources and data from remote sensing sensors to understand the state of the environment and provide solutions.

NASA's upcoming AIRSAR campaign in Central America is a unique opportunity to collect data over sites with the highest priorities for conservation science. AIRSAR's radar sensors operating at multiple wavelengths, polarizations, and interferometric modes allow a suite of measurements with very high resolutions to address three main objectives:

1. To collect data on the structure of tropical forests at varying stages of regrowth in order to help conservation groups understand and quantify past and present human impacts on the landscape.
2. To provide data on hydrological features of tropical coastal wetlands and mountainous landscapes to help develop models and protocols to mitigate the impacts of natural hazards and flooding in areas of high conservation and historical importance, and to reduce the long-term vulnerability of the region to cope with extreme climate events.
3. To test the unique capability of the AIRSAR system in measuring biomass and carbon content of dense tropical forests as a contribution to the global carbon cycle program and NASA's future spaceborne missions.

The AIRSAR campaign in Central America has brought together a large group of U.S. and Central American institutions and scientists. NASA's Jet Propulsion Laboratory, the Smithsonian Institute, Conservation International, Organization of Tropical Studies, NASA's Marshall Space Flight Center, Central American Commission for Environment and Development), Inter-American Development Bank and several local and U.S. universities and NGO's? are among the campaign's active partners.