The Aleut people in Sanak Island, Alaska are a super-generalist indigenous group able to thrive in a wide variety of living conditions while making use of different resources for their diet, a new study revealed.
Although this may seem dangerous for the resources within an environs, the Aleut people's behaviors as hunter-gatherers were actually found to be contributing to the stabilization of the ecosystem.
For approximately 7,000 years, the Sanak Aleuts hunted fish and marine animals in the nearby open water. They also collected shellfish and algae that were closer to shore.
To examine how human behavior affects complex ecological networks, a team of scientists pieced together a precise picture of the local marine food webs in Sanak Island by studying the shells and bones left behind in shell heaps or middens. These were obtained through oral histories from Aleut elders and from ecological data.
The team's study is the first ever investigation that included humans as external actors and an integral part of the ecosystem.
"It's the first highly detailed ecological network data to include humans, which allows us to ask questions about how they compare in their roles to other predators," says Jennifer Dunne, the lead researcher of the study and vice president for Science at the Santa Fe Institute.
The Twist
Dunne and her colleagues analyzed the structure of the local food webs. They found that within both nearshore and intertidal food webs, the Aleuts fed on nearly a quarter of the species present, far more consumption than the other predators in the ecosystem.
This diverse range of diet, from algae to sea lions, places humans in a niche similar to super-generalist predators such as the ray-finned Pacific cod.
Like other generalists, the Aleut people switched preys. When favored prey species became difficult to hunt because of population decrease or severe weather conditions, the group chose alternative sources for their food.
As such, in food webs and ecosystems where predators prey-switch, prey populations that have begun to dwindle can bounce back, researchers say. With this, extinctions are also rare.
"It's a very stabilizing behavior for the system," says Dunne.
Additionally, simple technologies such as spears, fish hooks and kayaks have helped the Aleut hunt several of their prey more intensively and effectively than expected for non-human predators.
The research suggests that as long as such intensive hunting was reserved and limited to only a few prey species, it would cause few extinctions.
Dunne noted that modernized fisheries set various kinds of pressure on food webs. Advancements in technology allow for highly intensive fishing. In some cases, as a prey species becomes scarce, its value goes up. For instance, bluefin tuna are a highly prized sushi fish.
The findings of the study are featured in the journal Scientific Reports.
