A new study conducted by researchers at the Santa Fe Institute examined humans on Sanak Island and Alaska, revealing their historical relationships with local species and suggesting that despite being super-generalist predators, the food-gathering behaviors of the local hunter-gatherers acted as stabilizers for 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," Jennifer Dunne, who participated in the research, said in a press release. "Unlike most ecological studies that ignore humans or consider them as external actors, our analysis includes them as an integral part of the ecosystem."
The Sanak Aleut hunter-gatherers hunted marine mammals and fishes for approximately 7,000 years. Dunne and her team put together a picture of the local marine food webs that they hunted by examining the bones and shells left behind through oral histories gathered from local Aleut elders and analysis of ecological data.
The results showed that in both the intertidal and nearshore food weds, humans fed on around a quarter of the species present, which is significantly more than other predators in the systems. This diet, which varied from primary products such as algae to top carnivores such as sea lions, placed humans in a niche much like other super-generalist predators like Pacific cod.
In addition, the team found that the Aleuts also prey-switched, much like other generalists. As a favored prey species became more difficult to find, typically due to a decline in their population or unfavorable environmental conditions, the Aleuts found alternative food sources. This is important for ecosystems due to the fact that prey existing in food webs where predators prey-switch can bounce back, rarely facing extinction.
"It's a very stabilizing behavior for the system," Dunne said.
The team also found that despite the more intensive hunting stimulated by the Aleuts' access to simple technologies such as fish hooks, spears and kayaks, the dynamics of the food web allowed for few extinctions.
The findings were published in the Feb. 17 issue of Scientific Reports.
