Fear drives the conservation of booming ecosystems according to a newly published study featuring in the Nature Communications journal.
It may uncomfortable to accept that large predators play a crucial role in maintaining the balance of an ecosystem. Human activity and hunting are driving large predator populations down. Some ecosystems have experienced a complete removal of large predator populations. Where this happened, the imbalance is rearing its head.
Liana Zanette, professor of biology with the University of Western Ontario, Justin Suraci, Ph.D., Lawrence Dill with the Simon Fraser University and colleagues headed to British Columbia Gulf Islands to understand the role of fear in the conservation of ecosystems.
Previous studies analyzed how fear work in relation with the food web. This study used raccoons on the British Columbia Gulf Islands to study the cascading effects of fear. The research led by professor Zanette confirmed that fear drives the conservation of booming ecosystems. In addition, inducing fear depends largely on the well-being of large predators.
All large predators on the British Columbia Gulf Islands have been wiped out by human activity. Once large populations of wolves, bears and cougars have been reduced to a mere memory. As a result, raccoons ate their way through fish, crabs and songbirds populations. As no large carnivores were around to impede the racoons from overeating, the sneaky animals filled their bellies without any impediment.
As the research team looked to gain deeper insight on the relation between introducing fear and a healthy ecosystem, they installed large speakers on the island. At times, the island would be inundated by wolf howls or dog barks. The results of this forward experiment were clear-cut.
The presence of large predators in the landscape introduces a new landscape of fear. Which may sound gloomy, yet it has the most beneficial effects for lower trophic levels and preventing their overconsumption.
In professor Zanette’s study, the lower trophic levels of the British Columbia Gulf Islands had much to gain just as the raccoons listened to the sounds coming from the speakers. As the sounds of large predators had all animals on the island in a more aggitated state than usual, raccoons spent 66 percent less time looking for food in the tidal zones.
To drive their point home, the research team analyzed the impact on species which are usually the favorite food of racoons. Fish populations increased by 81 percent. Local crabs populations increased by 61 percent. In addition, the team found 59 percent more worms.
According to the authors:
“Our experiment reversed this now unrestrained foraging by restoring the fear of large carnivores to a system from which it has largely been lost”.
Fear is key in driving ecosystem services without which certain species may perish while others could thrive unabated. Fear drives the conservation of booming ecosystems.
Photo Credits: Wikimedia