Hundreds of Reindeer Died by Lightning. Their Carcasses Became a Laboratory
“From death comes life,” said researchers who studied how decomposing bodies, with the help of scavengers, might alter plant diversity across a broad landscape.
On a chilly day in August 2016, more than 300 reindeer, huddled for warmth, dropped dead on a mountain plateau in Norway. They died by lightning, which coursed through the wet ground, climbed up their legs and fatally jolted their hearts.
Their bodies soon became a soup of nutrients and a rich feeding ground for scavengers, which dropped feces packed with seeds all around the carcasses.
That patch of land now has the potential to spawn new plant diversity from across a broad landscape, Norwegian scientists reported Wednesday in Biology Letters.
“From death comes life,” said Sam Steyaert, a researcher at the University of South-Eastern Norway and the Norwegian University of Life Sciences, and an author of the paper.
When Dr. Steyaert learned of the reindeer die-off, he saw an opportunity to turn a tragedy into a grand natural experiment.
He and a group of collaborators started a self-funded project. They named it REINCAR, which was short for reindeer carcasses, but also the start of the word reincarnation.
That October, the scientists set up their field laboratory. Each visit, they arrived to hundreds of ravens and crows, many smaller birds and the occasional circling eagle or buzzard. Their camera traps captured foxes and wolverines, among other visitors.
The cadavers still bore plenty of flesh but were ballooned from the gases released during decomposition and contained “all kinds of juice — and thousands and thousands of maggots, of course,” Dr. Steyaert said.
There were also piles of feces everywhere. Some droppings, the researchers noticed, were blue and loaded with crowberry seeds.
From survey plots, the scientists found that fox and bird feces were most concentrated in carrion-dense areas, supporting their suspicion that carcasses were magnets for scavengers. They confirmed in the lab that a large portion of crowberry seeds found in the feces could grow into seedlings.
The crowberry plant is a keystone species in the alpine tundra, serving as an important food source to many creatures and influencing nutrient cycles.
It’s thought that their seedlings, and those of similar plants, require bare, nutrient-dense soil to germinate.
Incidentally, “that’s exactly what the carcasses are creating,” Dr. Steyaert said, explaining that abrupt shifts in soil nutrients and acidity from rotting carrion kills vegetation.
Add a bunch of roaming scavengers that bring in a mix of seeds from a wide area, and you basically have “directed seed dispersal to the ideal germination spot,” he said
His team suspects the site will become a hot spot of genetic diversity for plants, as well as nutrients and microbes that scavengers help redistribute.
Ecologists typically think of carcasses as hyperlocal “decomposition islands,” said Jennifer Pechal, an assistant entomology professor at Michigan State University who was not involved in the study. The idea that carcasses can alter biodiversity across a wider landscape is “fascinating” and a “novel perspective,” she said.
Since mass mortality events are relatively rare (though they may be increasing in frequency), Dr. Steyaert also wants to study individual carcasses elsewhere. Still, he and his collaborators will continue monitoring this die-off site.
Over the last couple years, they have watched it evolve. The first spring was the smelliest time, with blowflies swarming everywhere. To deal with the stench, the researchers put menthol cream in their noses.
By last fall, it was mostly skin and bones, with almost no vegetation to be seen. This summer, there’s still skin and bones — but life is starting to return. Sedges and grasses are filling in, including a wavy hairgrass that bears purple flowers and makes the whole patch look pinkish from a distance. And just last week, when the researchers visited the site, they noticed a new addition: plenty of crowberry seedlings. Visit our website HERE