Hunting and other wildlife regulations can help stabilize animal populations, according to a new study from the Norwegian University of Science and Technology. The experts report that even low to moderate harvesting can help the remaining animals survive extreme weather and climate change.
“Harvesting or other means of regulating an animal population can sometimes have a positive effect by reducing the competition for food,” said study lead author Bart Peeters.
The researchers used statistical models and simulations to analyze the impacts of regulated hunting on animal populations. One of the models was developed specifically for Svalbard reindeer.
“Poor winter grazing conditions, such as thick snow cover or ice on the tundra, increase the competition for food. This has little impact when the population is small and few animals are competing for food. But in larger populations, a lot of animals will starve to death when bad weather conditions reduce available resources,” said Peeters.
Under extreme weather conditions, such as during frigid winter months, dense populations can collapse when food availability is scarce.
“Regulated hunting can have a positive effect since it reduces the number of animals before winter, so fewer animals need to compete for food then,” explained Peeters.
Professor Brage Bremset Hansen is the project manager from NTNU’s Centre for Biodiversity Dynamics and the Norwegian Institute for Nature Research (NINA), one of several project partners.
“By harvesting a number of animals through fall hunting, we reduce the population density and can avoid the amplified effect of poor winter grazing conditions. Hunting results in better conditions for the animals that survive the hunt. More animals will survive the winter, and a greater number will produce calves the next summer,” said Professor Bremset Hansen.
The experts say their findings can be applied to other species with limited food resources that are strongly impacted by weather conditions, such as other deer species affected by heavy snowfall.
“We show that bad weather conditions can severely reduce a population with a high density of animals. But harvesting as little as 5 to 10 percent of a population can reduce the mortality that would otherwise result from these bad weather conditions,” said Peeters.
In Svalbard, milder winters are now covering the tundra with ice, which can prevent reindeer from accessing their plant food.
“If the population density is high or the tundra is overgrazed, the competition for food will be even greater in tough snow conditions. This is especially true when winter rain leads to a thick ice cover on the ground,” said Peeters.
The study is published in the journal Ecology Letters.
By Chrissy Sexton, Earth.com Staff Writer