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"British Wildlife is the pulsating heart of the UK nature conservation movement"

Matthew Oates, National Trust

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"Packed with readable, thoughtful, up to date articles; written by ecologists and naturalists for ecologists and naturalists"

Nick Baker, Presenter and Naturalist

From issue:   Issue:   British Wildlife 11.4 April 2000

Assessing butterflies' status and decline

By - Martin Warren, Jeremy Thomas, Matthew Cowley, Chris Thomas

Measuring the range size of a species is essential if we are to assess its current status and thereafter analyse changes in its status. The usual approach is to examine grid-square distribution maps, and count up the numbers of squares in which the species occurs. However, each 2km (tetrad) or 10km (hectad) grid square contains land that is not occupied by the species in question, leading to systematic biases in estimates of current status and rates of decline.

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"British Wildlife is the pulsating heart of the UK nature conservation movement."

Matthew Oates, National Trust

"The most important and informative publication on wildlife of our times"

Michael McCarthy, The Independent

"Packed with readable, thoughtful, up to date articles; written by ecologists and naturalists for ecologists and naturalists"

Nick Baker, Presenter and Naturalist