Tracking elephants from space

It’s often said that certain geographical landmarks – like the Sahara Desert, or human-made structures like the Great Wall of China – are visible from space. But what about individual animals? 

In a collaborative project between the University of Oxford, UK, and the University of Twente, in the Netherlands, scientists successfully used high-resolution satellite cameras coupled with algorithms to count African elephants in a variety of landscapes.

Their research was published in the Zoological Society of London’s journal Remote Sensing in Ecology and Conservation.

The research team employed the high-resolution images taken by satellite Worldview 3 to record African elephants moving through their range. An automated system based on an algorithm developed by Olga Isupova, a computer scientist from the University of Bath, was able to locate elephants with the same accuracy as human observers on the ground.

“Accurate monitoring is essential if we’re to save the species,” says Isupova. “We need to know where the animals are and how many there are.”

As Worldview 3 hurtles through the exosphere it can capture 5000 square kilometres of land imagery every few minutes. Using satellite images eliminates the risk of disturbing animals, the need for low flying planes, and any harm that may come to humans during the data-collection process.

It’s not the first time satellites and AI have been used to detect species. Whales have been studied this way, but since they live in geographically uniform areas (the ocean) they proved to be much easier targets for Worldview 3’s high resolution cameras.

This research was particularly novel because it was able to detect the elephants across a number of different geographical backdrops, such as grasslands, forests and desert.

The feasibility of future satellite studies will be influenced by the high cost of commercial satellite imagery and the high volume of data that needs processing after collection. But processing compares favourably to traditional species-detection efforts – a few hours instead of fieldwork that may take weeks, or longer; and new commercial satellites, which may serve to lower costs, are due for launch this year.

Isupova believes we’ll soon be capturing pictures of much smaller species and expanding the use of satellite imagery in conservation efforts.

“Satellite imagery resolution increases every couple of years, and with every increase we will be able to see smaller things in greater detail,” she says. “We need to find new state-of-the-art systems to help researchers gather the data they need to save species under threat.”