Human-facilitated invasions
To investigate how earthworms spread in forests, we surveyed earthworms near lakes across northern Alberta. At each lake, we sampled near a boat launch, road, seismic line, and near remote sites farther from human disturbances (lake shores and forest interiors).
![](https://worms.biology.ualberta.ca/wp-content/uploads/sites/26/2010/03/content_researchIntroductions_01.jpg)
Earthworms were more likely to be found at boat launch and road plots (54%) than at the other plots (13%). Species commonly used as fishing bait also were found more frequently near boat launches (18%) than near roads alone (1%). These results suggest that transport by vehicles and bait abandonment are both important mechanisms of earthworm spread.
![](https://worms.biology.ualberta.ca/wp-content/uploads/sites/26/2010/03/content_researchIntroductions_02.jpg)
![](https://worms.biology.ualberta.ca/wp-content/uploads/sites/26/2010/03/content_researchIntroductions_03.jpg)
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