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Miconia Invasion of Hawai'i

David Duffy is tracking an invader, a menacing plant from Mexico that threatens to send Hawai'i's soil crashing into the sea. Brought to the islands in 1961 as an attractive nursery plant, Miconia managed to spread across 10,000 acres of the Big Island. This fast-growing interloper casts a lethal shadow over sun-hungry native plants. When the natives die, only the sparse, shallow roots of the reigning Miconia remain but their grip on the surrounding soil is weak at best. Furthermore, the large leaves of Miconia act as funnels for rainfall, channeling it into powerful streams that pummel and erode the surrounding soil even more. Volunteers and scientists are working hard to eradicate Miconia from Hawai'i.

What makes you most fearful for the future?
David Duffy Duffy: "That we will blend both cultures and environments into one monotonous worldwide uniformity and we won't know what we have lost..."

See David Duffy's full Q&A »

Asner: "Human ignorance of the unique and troubled existence of Earth's ecosystems..."

See Greg Asner's full Q&A »

Ecologist Greg Asner is trying to find a way to identify this harmful invasive species from aerial images. Flying over the Big Island, he measures the light reflected from the forest — including parts of the spectrum the human eye can't see. He then gathers Miconia leaves and records for each one a precise longitude, latitude and altitude using a device that can read signals from global positioning satellites even through a thick forest canopy (see The Importance of Remote Sensing, below). Asner compares leaf spectral measurements on the ground to the canopy's spectrum measured from the helicopter. He uses images of whole ecosystems shot from converted U2 spy planes and even bigger views of entire regions taken by satellite. Asner then puts these different views together. The result: from the air, he can identify Miconia infestations before they get out of control.

Related Links
» For more details on the techniques used by Greg Asner see AsnerLab: The Laboratory for Regional Biogeochemistry and Remote Sensing Off-site Link.


The Importance of Remote Sensing

Our ability to recognize Earth as a contained system came into focus when astronauts glimpsed our tiny blue home from space merely decades ago. At that time, we were able to view Earth in all its glory... and its vulnerability — a finite spaceship planet suspended in the velvet black void of space. This view came not a moment too soon. Our planet has been experiencing increasingly rapid changes due to our highly effective global capacity to extract and utilize resources. To more fully understand the degree of our impacts across the world, we need to more fully understand Earth as a system.

Remote sensing is now offering us the kind of global, continuous and repeatable observations of Earth systems that we need in order to grasp and manage our growing planetary impact. A new interdisciplinary field has emerged called Earth System Science (ESS) that embraces remote sensing and weaves together formerly disparate sciences as terrestrial ecology, oceanography and climatology. For more information see Earth System Science Education for the 21st Century. Off-site Link

Next: Invaders and Extinction »


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