By Greg Crutsinger
Scientific evidence clearly shows the earth is warming. Global temperatures are expected to increase by 2-4 °C over the next half century as a result of greenhouse gas emissions. Rising temperatures will impact the ecosystems that humans rely on for food, water and recreation.
Each of us can imagine the direct effects of warmer temperatures on our daily lives. We’ll need to invest in wide brim hats and breathable clothing and we’ll likely pay more to keep our homes and workplaces cool. But there will be countless indirect effects, too. For example, warmer temperatures will cause some plants and animals to move, or go locally extinct. The plants and animals that are able to survive without moving may change their behavior entirely. These changes will ripple through a complex web of interacting plants and animals.
Scientists obviously face a fundamental challenge in predicting these indirect impacts, but it’s a complicated task and so far scientists haven’t given it much attention. Two American ecologists affiliated with University of Copenhagen and the Rocky Mountain Biological Lab — Drs. Nate Sanders and Aimee Classen — are trying to change that.
Nate and Aimee both have impressive scientific records, with dozens of top-tier publications. They’re leading an international team to address the urgent need for more information on how climate change will affect ecological communities. They’re particularly interested in how it will influence biodiversity and how those differences will feed back to affect the environment at the Rocky Mountain Biological Lab (RMBL). RMBL is a historic and globally-renowned field station located in a silver mining ghost town called Gothic.
Here’s what Nate and Aimee are doing:
They are warming mountain meadows. How do you make an entire mountain meadow warmer? You use transparent hexagonal open-top chambers (OTCs) with an inside diameter of 1.5 m.
Basically these chambers act like mini-greenhouses. They’re used a lot in climate change studies to raise temperatures in remote areas. They’ll increase the average air temperature by about 2℃ (relative to control areas, which receive no artificial temperature change).
Along with being Parrot’s scientific program direction, I’m also an ecologist. I was lucky to have the chance to tag along with Nate and Aimee at their long-term field site at RMBL.
Drones have the potential to change — and dramatically improve — how scientists monitor ecosystems over time, so I brought along a couple drones and the new Parrot Sequoia multispectral camera. Nate and Aimee had never tried to capture this kind of aerial imagery, but they were excited to give it a shot.
Aimee told me, “Mountains are the ideal places to research how warming will alter ecosystems and the services they provide humans. For example, because mountains have slopes and many different climates, they harbor a large amount of plant and animal biodiversity. Mountains are also responsible for clean drinking water and they can store large amount of carbon in their soils. Thus, they are excellent test systems to study how warming can alter carbon and water cycles.”
Nate added that in mountains the temperature often corresponds to elevation. We all know temperatures tend to get cooler as you move higher. You can imagine that this predictable phenomenon would be valuable for ecologists out to understand how plant and animal communities respond to changes in climate.
In this experiment, Nate and Aimee were specifically studying plant communities. They set up the warming chambers at high and low elevations and then used pruning sheers to remove the dominant (that is, most common) plant species to assess how it affects biodiversity, relative to the changes in temperature.
Shifts in plant community compositions as well as warming often result in dramatic alterations of the water and carbon cycles, thus Aimee and Nate are experimentally removing plant species to investigate these shifts.
Incredibly, the team has replicated this same experiment at nine other sites around the world, from the Tibetan Plateau to Greenland to Patagonia. Drones will help them monitor the different study sites.
“Drones can repeat the same flight over and over again, which will allow us to set up a highly standardized survey protocol at each study site,” says Nate. “This will help us minimize error or ‘noise’ in our data collection. That kind of uniformity and replication is incredibly important in scientific studies.”
We also had a powerful data collection tool with us. The Sequoia camera is one of the smallest and lightest multispectral sensors on the market. Sequoia captures images across four defined visible and non-visible spectral bands — plus RGB imagery — in a single flight.
This means that each survey with Sequoia gets us an incredible amount of data. Mount Sequoia on a drone that can repeat its flights indefinitely, and you can create maps of all the different study sites which Aimee and Nate can use to calculate vegetation indices throughout growing seasons all around the world.
In addition to the multispectral data, the team will be able to use high-resolution color photos from Sequoia to monitor the different plant species in each location.
Figure 1. Upper lefthand corner depicts a stitched orthomosaic of color (RGB) photos of the high altitude warming site at RMBL. The upper right map shows the Normalized Difference Vegetation Index (NDVI) values of the study site calculated by using the ratio of two of the individual multispectral bands (red and near-infrared) on the Sequoia camera. The individual bands and RGB photos were then be used to generate three-dimensional point clouds of the study sites (lower map for NIR band). 3D point clouds can be use for a range of quantitative measurements, such as adding terrain contours or volumetrics. All stitching was done in Pix4D.
Nate, Aimee and their collaborators will work on this project for the next few years, and they are very excited about the potential drones have for their research.
“We’re exploring biodiversity in a changing world, in all corners of the world,” says Nate. “This research program has the potential to transform how we think about the effects of global climate change, as well as how we describe and document biodiversity in a changing world.”
To learn more about their research, you can check out their webpage here.
You can find more information on the Parrot Sequoia camera here.
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