Forest Habitat

Conifer forests are not the 'deserts' they seem.
New Scientist - Sept 1994 - Oliver Tickell

Britain's conifer plantations are not the ecological deserts proclaimed by environmental campaigners, but may contain 18 times as much insect life as the same area of native broadleaf woodland. "The invertebrates of plantation canopies can be fantastically abundant and diverse," say Andrew Foggo of the University of Oxford. "The popular conception is that conifers are dark, dank, acid, alien environment, simply because they are not rich in showy species like butterflies and primroses. But the small, unexciting species we have found are every bit as worthy of conservation."

Foggo and Claire Ozanne of the Roehampton Institute used the biodegradeable insecticide Pybuthrin 2/16 to "knock down" invertebrates from plantations of Norway spruce 30 to 35 years old in Bernwood Forest near Oxford. So far, he has counted 266,000 invertebrates in little more than 25 square

metres. This is equivalent to 10,640 organisms per square metre. Comparable measurements in mature oak woodland in nearby Berkshire have yielded a density of just 591 organisms per square metre.

To measure biodiversity in the forest, Foggo and Ozanne counted the number of species of spider in a given area of forest. They found 12 species in the average square metre, and 34 species over the 25 square metres that they analysed. This is comparable with the 25 species of spider recorded in 15 square metres of oak woodland in Berkshire. "We chose this even-aged conifer woodland because we thought there would be low abundances and little diversity, making it a neat, simple model to compare with moe complex systems," says Ozanne. "We found the converse."

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