Tag Archives: environment

Invasive Species – The Key to Ecosystem Recovery?

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Invasive species are a touchy subject for many environmental advocates, especially those working to protect biodiversity, endangered species and wild ecosystems. But what if they’re wrong about them and are ignoring invasive species to the detriment of their larger goals?

the new wild fred pearceThis idea lies at the heart of ‘The New Wild: Why Invasive Species Will Be Nature’s Salvation,’ the latest book from British journalist and author Fred Pearce. Provocative and engaging, it uses on-the-ground evidence to challenge many long held beliefs regarding alien and invasive species and provides a detailed history of the origins and progression of many dominant ecological ideas. These include that nature is pristine and perfectible, only native species are ‘good’ and ecosystems evolve to a balanced state.

But as Pearce writes, the nature of nature is to be highly dynamic, adaptable and open; perfection by definition would mean the end of change. He considers the ‘myth of the pristine’ to be “…some dangerous mythology about how nature works,” and that the demonization of non-native species says far more about humans and our collective fears of change than any traits or behaviors of the new species.

While most environmentalists have long thought that alien species serve no positive purpose in their adopted locations, in most instances they actually increase biodiversity, provide habitat, help remediate human caused pollution and generally get along with flora and fauna already there. As Christian Kull of Monash University notes, most landscapes are ‘melting pots’ and making any hard distinctions about what belongs where long have been meaningless.

ascension cloud forest
Ascension Island Cloud Forest, 90% non-native. Photo credit: http://www.ascension-island.gov.ac, used without permission.

Pearce utilizes many terms coined by various scientists and researchers in the book to elaborate on his points: ecological fitting, biotic resistance, extinction debt and punctuated equilibrium being just a few. He additionally writes about several locations where alien species have had profound impacts, almost entirely positive, including Ascension Island, Hawai’i, Australia, San Francisco Bay, the Florida Everglades, Surtsey and Puerto Rico.

Significant world events have occurred due to the presence of alien species. On the positive side, here in North America we wouldn’t have earthworms or European honeybees unless they were brought here. During the 19th century, ‘acclimatization societies,’ formed in the U.S. and elsewhere to introduce plants and animals from (usually) European landscapes.

Also in the late 19th century, Africa was forever altered by an Asian microbe, brought by the cattle of Italian soldiers, that causes rinderpest. This cattle virus infected a wide variety of cloven-hoofed animals across Africa and led to significant die offs. As Pearce writes, “Herders had no livestock, and farmers had no oxen to pull their plows or drive the waterwheels that irrigated their fields.” People starved decimating many cultures, including the Masai (Kenya), Tutsi (Rwanda), Soga (Uganda), Nama and Herero (SW Africa) and Fulani (Nigeria); most never fully recovered. The outbreak “depopulated and impoverished Africa on a scale” that greatly exceeded the effects of the slave trade. Drought occurred simultaneously in some areas and with few grazers around, the tsetse fly, an endemic insect, flourished in the overgrown bush. Taken together this enabled the final colonization of Africa in the late 1800s / early 1900s.