Efforts are underway to see if vegetation such as cloudberry, sphagnum moss and low bush cranberry, common species in Kenai Peninsula peatlands, can be identified by their reflectance with remote-sensing technology. (Photo provided by Kenai National Wildlife Refuge)

Efforts are underway to see if vegetation such as cloudberry, sphagnum moss and low bush cranberry, common species in Kenai Peninsula peatlands, can be identified by their reflectance with remote-sensing technology. (Photo provided by Kenai National Wildlife Refuge)

Refuge notebook: Monitoring wetland change on the Kenai

For the past year I’ve been sitting in a university office in Eastern Pennsylvania staring at maps of the Kenai Peninsula. The maps show the peninsula striped by eight slender (1,000-feet wide) red ribbons, extending north-south.

These stripes show where NASA flew an airplane campaign with instruments aboard that gathered information about the surface below. These instruments, LiDAR and a spectrometer, produced images of the landscape and its vegetation — images in which each pixel is not just a color but a small treasure trove of cached data.

It came as a pretty big surprise to me that NASA flies aircraft other than rockets, or that they’re interested in understanding not just outer space but the inner space envelope that is our earth’s atmosphere. But NASA’s Goddard Space Flight Center does exactly that. It was staff from the Goddard Center who flew the flight lines in August 2014.

ADVERTISEMENT
0 seconds of 0 secondsVolume 0%
Press shift question mark to access a list of keyboard shortcuts
00:00
00:00
00:00
 

The LiDAR instruments onboard the airplane collect information about the height of what’s on the ground by sending down a laser pulse, and measuring the time it takes for the pulse to reach the first object in its path and bounce back. That return pulse is the “the first return.” The pulse fragments when it hits that first object and a portion of the pulse continues downward hitting lower objects. The final object the pulse hits is usually the ground and is called “the last return.”

We can calculate the distance that pulse traveled by knowing its speed (the speed of light) and the time it took to travel down and back. Now multiply that by millions of pulses and we can see how LiDAR creates a 3D image of the height of everything it flies over. LiDAR lets us map the height of vegetation from high canopied forests to low-lying wetlands.

The second instrument, a spectrometer, takes an image of the reflectance that an object gives off. To think about this spectral-reflectance concept it’s helpful to recall that everything on earth absorbs and reflects light.

Our dark clothing absorbs light while our white clothes reflect more light. If we extend this idea to colors, and think about how plants appear green because they actually reflect wavelengths in the green region of the spectrum, we can start to envision how everything on earth has its own “spectral profile.”

Why is this NASA data special? First, the images are “high resolution,” meaning each pixel in the image represents a 1-meter-square patch on the ground.

Secondly, the LiDAR and hyperspectral data were collected simultaneously so we know with a high degree of confidence that it tells us both the height of the materials and gives us a highly detailed spectral profile of what’s in any meter-square pixel.

Put these together, and we have a powerful tool for potentially understanding, over a vast spatial area, exactly what vegetation is on the Kenai landscape.

By now you might be asking yourself, who cares? Plants are plants, right? We’re glad to have them, the caribou are glad to have them, the moose are glad to have them. But why do we care which plants are where?

This is where the complexity of plants comes into play. Plants don’t just sit on the earth’s surface, but exist in a highly complex web of processes at the earth-atmosphere interface.

When the type of plants dominating a space changes, transitions for instance from a forest to a grassland, then the amount of water in the soil, the pH, the temperature, and the microorganisms in the soil also shift.

All this shifting can impact everything on the land from its relative risk of fire, to how much carbon is stored in the soil, to how well the environment suits the animals that live there.

As a graduate student at Lehigh University, my research centers specifically on vegetation changes in peatlands. Peatlands are wetlands, often dominated by sphagnum-moss or sedges, where the pace of vegetation decomposition is slower than the rate of vegetation accumulation.

Over time, thick layers of decomposed plant deposits build up. And these deposits of plant material hold tremendous amounts of carbon. In fact, northern latitude peatlands cover just 3% of the earth’s surface but hold about 30% of the world’s soil carbon. This means the soils on the Kenai Peninsula and elsewhere in most of Alaska serve as a critical global carbon repository.

A first step in understanding how to keep the carbon in the soil and to protect wildlife habitats is to understand where and why vegetation is changing.

I will use statistical modeling to compare the 2014 NASA image-data, to image-data NASA plans to collect (over the same locations) later this summer. My goal is to use this high-resolution data to quantify where and how vegetation has changed on the Kenai over the past five years.

Now the paper maps I’ve been staring at for so long are a living, breathing, breathtaking landscape. I’m ready to go out and look at vegetation on the ground. I’ll be trying to turn those data into something useful. Some sort of knowledge that can help keep the Kenai its ageless, beautiful self.

Heidi Cunnick is a PhD candidate in the Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, PA. Find more Refuge Notebook articles (1999-present) at https://www.fws.gov/Refuge/Kenai/community/Refuge_notebook.html.

More in Sports

Runners take off from the start of the 36th annual Violence Free Community Run on Saturday, Aug. 9, 2025, in Kenai, Alaska. (Photo by Jeff Helminiak/Peninsula Clarion)
Participation at Violence Free Community Run jumps to 73

The 36th annual Violence Free Community Run jumped to 73 participants Saturday… Continue reading

tease
Aldridge takes overall win at 5th Soldotna Cycle Series race of season

Morgan Aldridge took the overall win at the fifth race of the… Continue reading

Kenai River's Luke Hause moves with the puck during a hockey game at the Soldotna Regional Sports Complex in Soldotna, Alaska, on Friday, Feb. 16, 2024. (Jake Dye/Peninsula Clarion)
Former Brown Bears player Hause commits to DI Long Island University

Luke Hause, a former defenseman for the Kenai River Brown Bears, announced… Continue reading

Seward's Chaz DiMarzio dismounts his bike after winning the Soggy Bottom 100 on Saturday, Aug. 2, 2025, in Hope, Alaska. (Photo provided)
Seward’s DiMarzio wins Soggy Bottom 100 for 4th time

Mountain biker overcomes constant rain, broken handlebar

Allie Ostrander is presented her award by Stacia Rustad at the Alaska High School Hall of Fame's Class of 2023 induction ceremony on Sunday, May 7, 2023, at The Lakefront Hotel in Anchorage, Alaska. (Screenshot)
Ostrander scratches from steeplechase final at US Nationals

Allie Ostrander, a 2015 graduate of Kenai Central now a pro runner… Continue reading

Hikers climb a steep portion of Gtace Ridge during the 2025 Kachemak Bay Mountain Classic on Saturday. The race was 9.2 miles and racers faced a 3200’ elevation gain. (Photo courtesy of Amy Holman)
37 compete in annual Kachemak Bay Mountain Classic

This year’s race was held at Grace Ridge Trail

Homer junior Johannes Bynagle expands his lead midway through the Colony Invitational on Saturday, Aug. 31. 2024, at Colony High in Palmer, Alaska. (Photo by Jeremiah Bartz/Frontiersman)
Fishburn, Bynagle net The Great Salmon Run victories

Tori Fishburn and Johannes Bynagle won the third edition of The Great… Continue reading

Morgan Aldridge leads riders down a hill at the start of Week 3 of the Soldotna Cycle Series on Thursday, July 18, 2019, at Tsalteshi Trails. (Photo by Jeff Helminiak/Peninsula Clarion)
Aldridge rolls to victory in 4th race of Soldotna Cycle Series

Morgan Aldridge took the women’s and the overall win Thursday, July 31,… Continue reading

Soldotna's Ollie Dahl leads Seward's Ridge Conant at the start of the freshmen-sophomore boys race Monday, Aug. 19, 2024, at the Peninsula Class Races at Nikiski Middle-High School in Nikiski, Alaska. (Photo by Jeff Helminiak/Peninsula Clarion)
Dahl captures Salmon Run Series 4

Ollie Dahl won the fourth race of the Salmon Run Series on… Continue reading

Most Read

You're browsing in private mode.
Please sign in or subscribe to continue reading articles in this mode.

Peninsula Clarion relies on subscription revenue to provide local content for our readers.

Subscribe

Already a subscriber? Please sign in