‘Even in protected areas, the influence of humans might be greater than we previously thought … ‘
By Summit Voice
FRISCO — As much as we’d like to believe in nature unbound, a new Canadian study suggests that human impacts are more widespread than we realize, even extending well into protected areas.
The five-year study by University of Calgary ecologists, included monitoring wolves, elks, cattle and humans. The resarchers concluded that human activities dominate all other factors, even in protected areas.
“Our results contrast with research conducted in protected areas that suggested food chains are primarily regulated by predators. Rather, we found that humans influenced other species in the food chain in a number of direct and indirect ways, thus overshadowing top-down and bottom-up effects,” said lead author Dr. Tyler Muhly.
The study was a collaboration between NSERC, Shell Canada, Parks Canada, the Alberta Government and the Universities of Alberta and Calgary. The ecologists used dozens of animal tagging devices and motion sensor-activated cameras to study human, animal and plant distribution throughout southwest Alberta. The research area stretched from Calgary in the northeast, through to the provincial borders with British Columbia in the west and the US-Canada border in the south.
“Understanding the significance of the impact that humans have on ecosystems is a critical component in formulating long-term and effective conservation strategies,” said reseacher Marco Musiani. “Our results led us to believe that ecologists have underestimated the impact of humans on natural food chains. The data we collected shows that humans are deliberately or inadvertently engineering ecosystems regardless of whether they would be naturally pre-disposed to top-down or bottom-up effects. Even in protected areas, the influence of humans might be greater than we previously thought,” Musiani said.
Ecologists have long debated whether natural ecosystems and associated food chains are primarily regulated by predators or by the productivity of plant species, called top-down and bottom-up effects, respectively. With most of the world’s ecosystems now dominated by humans, researchers from the University of Calgary sought to understand how much people influenced food chains in southwest Alberta.
“We painstakingly monitored wolves, elk, cattle and plant species, as well as humans for five years. We evaluated how these species interacted across the landscape and ultimately found that humans dominated the ecosystem,” Muhly said.
“In particular, we found that forage-mediated effects of humans (bottom-up effects) were more influential than predator-mediated effects in the food chain. The presence of humans was most correlated with occurrence of forage (plants). Elk and cattle distribution correlated closely with forage, and the distribution of wolves matched that of the elk and cattle they view as potential prey.
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