Is the native British bluebell threatened by Spanish and hybrid bluebells?

Hyacinthoides non-scripta

The native British bluebell, Hyacinthoides non-scripta, is thought to be at risk from ‘Spanish' and hybrid (collectively, ‘non-native') bluebells. The Spanish species, Hyacinthoides hispanica, was introduced to the UK by the late 17th century and scores of ornamental cultivars named as H. hispanica have been popular garden plants for at least 100 years. By the late 1980s garden-type bluebells had reached a notable level of prevalence beyond gardens, in locations such as roadsides, riversides, waste ground and amenity woodlands. It is supposed that H. hispanica naturalised in gardens and subsequently escaped from cultivation. In fact, the identity and origins of the non-native bluebells in Britain are the subject of active study, and it is likely that the many forms of naturalised hybrids between British and Spanish bluebells, H. x massartiana, dominate.

The threat to H. non-scripta would come from increasing hybridisation with non-natives and from losing ground, literally, to a superior competitor. Little data have been available to resolve specific disagreements about several key aspects of this scenario, including the numbers of non-native bluebells present in semi-natural environments, the extent of their co-occurrence with natives, and characteristics such as dispersal, responses to climate and interfertility. Since 2004 we have been studying natives and non-natives in the wild, the nursery and in common-gardens across southern Scotland. The results will help us to determine the current status and assess the future prospects for Britain's favourite wild flower.

The study has two parts:

  1. a large-scale survey (2004-2006) to quantify abundances of the two taxa and relate them to land use and weather averages
  2. an experimental evaluation of relative performance (2005-2008), in which individuals from reference populations of natives and non-natives are grown side-by-side at 7 sites experiencing different natural combinations of temperatures and rainfall.

For further information contact Deborah Kohn

Publications

Kohn DD, Hulme PE, Hollingsworth PM, Butler A (2009) Are native bluebells (Hyacinthoides non-scripta) at risk from alien congenerics? Evidence from distributions and co-occurrence in Scotland. Biological Conservation 142:61-74.
 

See also the related Molecular Ecology project on Genetic markers, hybridisation and bluebells and our Bluebell image gallery 

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