How to count insects from spaceon October 21, 2020 at 11:00 am

But there is a glimmer of hope in an unexpected place: space. And it doesn’t require fancy sensors or expensive new satellites. As researchers from the University of Wurzburg reported in a 2019 paper in Nature Communications, “Radar Vision in the Mapping of Forest Biodiversity from Space,” it turns out that freely available radar data can be used to figure out where even the smallest insects live.

To make this work, scientists first perform comprehensive “ground truth” studies. They take a thorough look at just which insects are living in an area, attracting them using bright lights or setting out pitfall traps to lure and contain them. From these biological field surveys, they build up a picture of insect biodiversity. Then they feed that data to a machine–learning algorithm, along with radar and lidar data from satellites that have scanned the same area. This trains the algorithm to correlate variables like an area’s species richness and species composition with specific patterns in satellite images. These patterns are not necessarily apparent or comprehensible to the human eye. So while we might look at images from the Sentinel-1 satellite and see interesting pixels on a screen, the algorithm can look at those same pixels and, based on what it has learned from other inputs, make predictions about the distribution of species in the place it’s surveyed. If the imaging ticks the boxes for a specific degree of forest maturity, researchers could then infer insect diversity from what they know of similar forests.

At least a million species will face extinction within the decades to come, half of them insects. And without insects, entire food chains collapse.

For humans to survive into the future, we need to know where biodiversity loss is happening the fastest. Monitoring it in insect species will help researchers and policymakers formulate a plan of action. Since the start of the industrial era, it is likely that around 5% to 10% of all insect species have gone extinct. In the last 25 to 30 years alone, 80% of insect biomass on the planet has vanished.

But not you, little beetle. Not yet, anyway.

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