News FocusConservation Ecology

Embracing Invasives

Science  18 Mar 2011:
Vol. 331, Issue 6023, pp. 1383-1384
DOI: 10.1126/science.331.6023.1383

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Summary

Much of the fauna and flora of the Galápagos islands is unique, but introduced species are taking over. Conservationists have spent the past 50 years attempting to remove introduced species and restore the islands' flora and fauna to prehuman days. There have been some successes: Goats have been eliminated from several islands. But the effort to eradicate blackberry, guava, and 34 other invasive plant species has cost more than $1 million and succeeded in eliminating just four. The most invasive and problematic of these aliens—blackberry and guava—have developed into forests where nothing else grows, birds cannot nest, and even insects are rare. The main reason for this failure is that invasive plants are far more competitive than native plants. Seeds of invasive species, such as blackberries, are long-lived and accumulate in high numbers in the soil, and restoration activities can have the paradoxical effect of stimulating them to germinate. Now, a group of maverick ecologists is promoting the idea that the addition of nonnative species to natives in a region leads to "novel" or "hybrid" ecosystems that have ecological value and may be worthy of conservation.

* Gaia Vince writes on environmental issues in the developing world at wanderinggaia.com.