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Human impacts on natural world `underestimated`

Last Updated: Saturday, May 11, 2013 - 09:36

Washington: Two accepted principles of how ecosystems naturally operate could be overshadowed by the importance of human activity, a study has claimed.

The comprehensive five-year study by University of Calgary ecologists includes monitoring the activity of wolves, elks, cattle and humans.

Principal investigator Marco Musiani said that understanding the significance of the impact that humans have on ecosystems is a critical component in formulating long-term and effective conservation strategies.

He said that the results led them to believe that ecologists have underestimated the impact of humans on natural food chains.

He asserted that the data that they 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.

Musiani said that even in protected areas, the influence of humans might be greater than it has been previously thought.

Lead author Tyler Muhly, PhD, said that the study - a collaboration between NSERC, Shell Canada, Parks Canada, the Alberta Government and the Universities of Alberta and Calgary- relied upon dozens of high-tech animal tagging devices and motion sensor-activated cameras to study human, animal and plant distribution throughout southwest Alberta.

The study 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.

Muhly said that they painstakingly monitored wolves, elk, cattle and plant species, as well as humans for five years and evaluated how these species interacted across the landscape and ultimately found that humans dominated the ecosystem.

He asserted that in particular, the team found that forage-mediated effects of humans were more influential than predator-mediated effects in the food chain.

Muhly said that the presence of humans was most correlated with occurrence of forage and 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.

He said that their results contrasts with research conducted in protected areas that suggested food chains are primarily regulated by predators.

He added that rather, they 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.

The results of this study has been published in PLOS ONE.


First Published: Saturday, May 11, 2013 - 09:36

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