Surprising predictor of ecosystem chemistry

Apr 08, 2013
On the left is a true color image of a region in Jasper Ridge captured by CAO AToMS. On the right is the same region showing plant chemical diversity -- red areas are high in leaf carbon, green areas are high in leaf nitrogen, and blue areas are high in leaf water. Dark areas (mostly senescent grasses) are low in all three chemicals. Credit: Image courtesy Kyla Dahlin, CAO

Carnegie scientists have found that the plant species making up an ecosystem are better predictors of ecosystem chemistry than environmental conditions such as terrain, geology, or altitude. This is the first study using a new, high-resolution airborne, chemical-detecting instrument to map multiple ecosystem chemicals. The result, published in the April 8, 2013, Early Edition of the Proceedings of the National Academy of Sciences, is a key step toward understanding how species composition affects carbon, nitrogen and other nutrient cycling, and the effects of climate change, land use, and other ecosystem pressures.

Two important ecological goals are to understand the distribution and diversity of plants in their environment and how nutrients and energy flow through ecosystems. Both are essential to predict how the environment may change in the future, but untangling the relative importance of different influences has remained challenging.

Lead author Kyla Dahlin explained: "We used the high-resolution mapping capabilities of the Carnegie Airborne Taxonomic Mapping System (CAO AToMS), and found that the plant communities that make up Jasper Ridge Biological Preserve in Northern California were the strongest predictors. They explained 46% to 61% of the variation in plant chemical traits, and these traits hold the key to how ecosystems function."

The plant communities at Jasper Ridge include savanna/grasslands, evergreen oaks and chaparral, , and more. The researchers measured four traits mapped with CAO AToMS from the air: leaf nitrogen, leaf carbon, leaf water concentration, and canopy water content.

The researchers combined the airborne data with maps of known environmental regulators, such as terrain and geology, and maps of plant communities and land-use history to ask whether environmental conditions or plant communities were more indicative of the chemical variation of the vegetation. They found that environmental conditions played a role, but that plant communities were the stronger predictor.

Co-author Greg Asner, principal investigator of the CAO, commented, "The results are a powerful demonstration of the use of the latest airborne spectroscopic mapping techniques to understand the multiple chemicals in the foliage of vegetation, allowing us to relate the chemical information to biodiversity and environment. These are the tools of the future for ecological research and conservation science."

"This study is especially exciting for Carnegie because it answers questions about the roles of landscapes and that were posed by Carnegie investigators in the early decades of the 20th century," said co-author Chris Field, director of the Department of Global Ecology.

Explore further: Next-door leopards: First GPS-collar study reveals how leopards live with people

Related Stories

Termites foretell climate change in Africa's savannas

Sep 07, 2010

Using sophisticated airborne imaging and structural analysis, scientists at the Carnegie Institution's Department of Global Ecology mapped more than 40,000 termite mounds over 192 square miles in the African ...

Airborne technology helps manage elephants

Aug 06, 2012

For years, scientists have debated how big a role elephants play in toppling trees in South African savannas. Tree loss is a natural process, but it is increasing in some regions, with cascading effects on the habitat for ...

Recommended for you

Laser scanning accurately 'weighs' trees

Nov 21, 2014

A terrestrial laser scanning technique that allows the structure of vegetation to be 3D-mapped to the millimetre is more accurate in determining the biomass of trees and carbon stocks in forests than current ...

Cameras detect 'extinct' wallabies near Broome

Nov 21, 2014

Yawuru Country Managers have found a spectacled hare wallaby (Lagorchestes conspicillatus) population, a species which for the last decade was feared to be locally extinct at Roebuck Plains, adjacent to Broome.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.