Balance of nature: ecosystems change from human waste food (Introduction)

by David Turell , Tuesday, October 13, 2020, 18:40 (1501 days ago) @ David Turell

The study is fascinating in that top predators may change their population sizes and bring competition:

https://www.sciencedaily.com/releases/2020/10/201012164219.htm

"Ecologists at the University of Wisconsin-Madison have found that carnivores living near people can get more than half of their diets from human food sources, a major lifestyle disruption that could put North America's carnivore-dominated ecosystems at risk. The researchers studied the diets of seven predator species across the Great Lakes region of the U.S. They gathered bone and fur samples for chemical analysis from areas as remote as national parks to major metropolitan regions like Albany, New York. They found that the closer carnivores lived to cities and farms, the more human food they ate.

"While evolution has shaped these species to compete for different resources, their newfound reliance on a common food source could put them in conflict with one another. That conflict could be reordering the relationship between different carnivores and between predators and prey, with an unknown but likely detrimental impact on ecosystems that evolved under significant influence of strong predators.

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"'Isotopes are relatively intuitive: You are what you eat," says Manlick. "If you look at humans, we look like corn."

"Human foods, heavy in corn and sugar, lend them distinctive carbon signatures. In contrast, the diets of prey species in the wild confer their own carbon signatures. The ratio of these two isotope fingerprints in a predator's bone can tell scientists what proportion of their diet came from human sources, either directly or from their prey that ate human food first.

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"'When you change the landscape so dramatically in terms of one of the most important attributes of a species -- their food -- that has unknown consequences for the overall community structure," says Pauli. "And so I think the onus is now on us as ecologists and conservation biologists to begin to understand these novel ecosystems and begin to predict who are the winners and who are the losers.'"

Comment: We humans affect everything. Hopefully we can help correct unwanted changes.