Where Do Camels Belong? by Ken Thompson

Author:Ken Thompson
Language: eng
Format: epub
Publisher: Profile Books
Published: 2014-02-21T05:00:00+00:00

USEFUL ALIENS

Sometimes eradication efforts are halted by the discovery that the target is actually doing something useful. From the 1960s to the 1980s, the US Department of Agriculture (USDA) introduced many alien honeysuckle species in land reclamation projects, and to improve bird habitats. They then changed their mind, declared several species of introduced honeysuckles to be harmful and banned their sale in more than 25 states. But they may have been right in the first place. Recent work in Pennsylvania has found that more non-native honeysuckles means more native bird species – three to four times as many native birds in one site. Also the seed dispersal of native berryproducing plants is higher in places where non-native honeysuckles are most abundant.

New Zealand is short of insect pollinators, so vertebrate pollination is common; even in species that look like they should be insect-pollinated, vertebrates often make an important contribution. A study of three New Zealand woody plants found that their flowers were visited by a bat, a gecko and five native bird species. All these pollinators survive on offshore islands, but are now rare or extinct on the mainland, where the flowers are now visited – and pollinated – by the ship rat and by an alien bird. So even though the ship rat was probably partly responsible for the loss of some of the native vertebrates it’s now doing the job they used to do. Ship rats are unlovely and unloved, and that won’t be enough to save them from attempts at extermination, but it’s worth knowing that such attempts may have unintended consequences; even ‘problem’ aliens may turn out to have their uses.

It’s also true that in a world increasingly altered by humans aliens may sometimes simply be the best species for the job. A nice example can be seen in the Don Valley Brick Works, the abandoned 40-acre site of Ontario’s longest-functioning brickyard, which is now an important part of Toronto’s network of green spaces. In its early years the site was managed by the Toronto and Region Conservation Authority (TRCA), and is currently co-managed by the City of Toronto’s Parks and Recreation Department and Evergreen, a Canadian NGO that strives to conserve natural and cultural landscapes. The mission of all these bodies has been to restore a clean, green and accessible Don River watershed.

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