Orchid’s secret note

Global warming forces it to bloom early

By Tiasa Adhya
Published: Monday 15 November 2010

ORCHIDS that the Victorian era naturalists plucked and carefully pressed onto vellum sheets confine climate secrets. A recent study of these orchids revealed over the years global warming has changed their blooming pattern: the spring flower now blooms prematurely in the UK.

Rimageesearchers from University of East Anglia, University of Kent, University of Sussex and Royal Botanic Gardens studied 77 specimens of the early spider orchid (Ophrys sphegodes) collected between 1948 and 1958 and preserved at London’s Natural History Museum.

The orchids, which once grew across central and southern Europe, are now confined to southern UK. Because each specimen contains details of when and where it was picked, the researchers matched the details with meteorological records to examine how mean spring temperatures affected the orchids’ flowering.

They then compared the data with field observations of peak flowering of the same orchid species in the Castle Hill National Nature Reserve, East Sussex from 1975 to 2006. They discovered that changes in flowering time in response to temperature were identical both in herbarium specimens and field data. In both instances, the orchids flowered six days in advance for 1oC rise in the average spring temperature.

The results are the first direct evidence that herbarium specimens can be used to gauge the trend of global warming induced climate change.

Orchids have co-evolved with insect pollinators, said Roy Thompson, an independent scientist at Edinburgh University. Research should be done on possible disruption of pollination as a result of differential responses to climate change, he said. Lead researcher Anthony Davy said his team plans to look at the activity of potential pollinators from museum collections and understand how climate change has affected their relationship with the orchids.

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