Invasive Species Can Drastically Alter food webs •


Much evidence shows that invasive species damage food webs, but the details of that damage over time remain somewhat mysterious. A new study on University of Montana The Flathead Lake Biological Station offers new insights into the effects of invasive species.

“This has been a really collaborative effort,” said Shawn Delvin of FLBS. “The work uses the rather grim history of the introduction and invasion of non-native species in the northwestern Montana Lakes in an ecological experiment based on the power of long-term data and a deeper understanding of lake ecology.”

The American fish and wildlife biologist Charles Wainright, who has just completed his PhD at FLBS, explained the importance of the study.

“This study provides new details on how invasive lake trout affect entire sea food webs,” said Wainright. “The results will be important to the conservation of native species and ecosystems in Montana and elsewhere.”

Researchers examined long-term fishery records to determine when invasive lake trout were introduced in ten Montana lakes. The researchers also examined the effects of these introductions on the food webs in the lakes.

The results showed that native fish were forced to eat less than ideal and scratch around in unfamiliar habitats. This eventually led to the loss of the native bull trout, an endangered species under the US Endangered Species Act.

“Native bull trout populations have declined dramatically in many lakes in western Montana due to competing interactions with invasive lake trout,” said Clint Muhlfeld, an aquatic ecologist with the USGS.

“For the first time, we are showing what happens not just to bull trout, but entire food webs that support them when lake trout invade over time and disrupt lake ecosystems.”

Research showed that the invasive fish populations have grown over time over decades. After 50 years, the lake trout was the dominant top predator in these food webs.

The results confirmed that invasive lake trout over time destroyed – and eventually replaced – the native fish species and drastically changed the ecosystem.

The study is published in the journal Proceedings of the National Academy of Sciences,

from Zach Fitzner, Employed author

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