UM & NASA Researchers Use Laser Sensor in Search for Ivory-Billed Woodpecker

COLLEGE PARK, Md. -- A team of researchers from the University of Maryland and NASA Goddard Space Flight Center are imaging areas of habitat suitable for the ivory-billed woodpecker, the largest and most regal member of the woodpecker family, which may still survive some 60 years after it was thought to have gone extinct.

The team just completed two weeks of flights over delta regions of the lower Mississippi River using an aircraft carrying NASA's Laser Vegetation Imaging Sensor, which has a unique ability to peer into dense forests to reveal the internal structure of the vegetation, as well as information about the terrain beneath the forest canopy. They are now working to analyze the data taken during the flights and translate it into maps of canopy cover, biomass and other measures of forest structure that will be used to identify areas where ivory-billed woodpeckers are most likely to be found.

The mapping project is latest step in a more than two-year effort to find irrefutable evidence that a bird, once thought to have been extinct for decades, continues to survive.

LVIS images from the ivory-billed project are not yet available. The above image from a previous project shows a three-dimensional view of trees and other vegetation in the tropical forest of La Selva, Costa Rica. The color indicates the amount of laser energy reflected from trees and leaves back to the sensor onboard the aircraft. Credit: John Weishampel, University of Central Florida.

"Through numerous studies, we have shown the effectiveness of the data generated by lidar for many scientific uses, including carbon sequestration, fire modeling and prediction, and habitat characterization," said LVIS project researcher Ralph Dubayah, a professor in the University of Maryland's department of geography. "Lidar [light detection and ranging] provides measures of the vertical structure of the canopy and ground. This sets it apart from other remote sensing systems, such as Landsat, that provide detailed horizontal information, but can say very little, for example, about whether a green patch of forest is short or tall. We know that for habitat characterization and suitability, the vertical structure of the canopy is of paramount importance to many species, including the ivory-bill."

The Laser Vegetation Imaging Sensor contains lasers that send pulses of energy to the Earth's surface. Photons of light from the lasers bounce off leaves, branches and the ground and reflect back to the instrument. By analyzing these returned signals, scientists receive a direct measurement of the height of the forest's leaf covered canopy, the ground level below and everything in between.

Return of the Ivory-Billed Woodpecker

In April, 2005, that team published a report in the journal Science that at least one male ivory-bill still survived. Their findings included multiple sightings of the elusive woodpecker, audio recordings and frame-by-frame analyses of brief blurry video footage. However, some scientists have challenged whether it really was the ivory-billed woodpecker that actually was spotted. In May, a six-month search of eastern Arkansas led by the Cornell Lab of Ornithology, with support from Audubon Arkansas, failed to find further evidence of the bird.

The red border shows the forested area in the White River Wildlife Reserve of Arkansas where researchers flew in June and July, 2006 to identify a possible habitat for the ivory-billed woodpecker. Credit: NASA

The Maryland/Goddard project mission is designed to provide habitat maps that search teams will use, beginning this fall, for additional, expanded efforts to find new evidence for the survival of this legendary bird.

"The 3-dimensional maps of canopy structure obtained during these flights will aid greatly in the continued search for the ivory bill," said Maryland scientist Michelle Hofton, who is in charge of planning and deployment for the mission, and of processing the data generated. "These lidar maps reveal the uniqueness of the forests, and verify the importance of continuing to preserve such areas as habitat for the ivory-billed woodpecker, and other bird and animal species."

Funded mainly by the U.S. Fish and Wildlife Service and the U.S. Geological Survey, the project is just one example of a broad range of lidar (light detection and ranging) applications, according to NASA Goddard's Bryan Blair, principal investigator for the Laser Vegetation Imaging Sensor (LVIS) instrument.

"This field campaign using LVIS data to support ground actvitites is an excellent example of an application of lidar data," Blair said. "Some projects use LVIS data as a part of an effort to develop approaches that fuse different types of remote sensing data and apply this combined data to a scientific research problem or, as in this case, to an operational application such as monitoring bird habitat."

The team of University of Maryland and NASA researchers previously has used this innovative laser instrument to study wildlife habitats in "old-growth" forests in the western United States and in tropical rain forests.

The University of Maryland is a leader in the application of remote imaging to the study of wildlife habitat, deforestation and other land cover changes, sea level rise and climate change.

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