7. Are alien species always a net negative? (Martin Schlaepfer)

Invasive alien species are considered one of the five main direct drivers of biodiversity loss, worldwide, as well as causing untold damage to economic assets like agriculture. Is there ever anything to be said for accepting them into the landscapes or seascapes they've occupied? And what about non-invasive alien species, and invasive native species? 

Martin Schlaepfer is an ecologist and senior lecturer at the University of Geneva. He has diverse experience across the field of conservation biology in North America and Europe.

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