Morphology and pollen fertility of native and non-native bluebells in Great Britain

ABSTRACT

Background

There is considerable concern that the native British bluebell Hyacinthoides non-scripta (Asparagaceae) is at risk due to hybridisation with naturalised British non-native bluebells. However, the taxonomic identity of British non-natives is uncertain, and they are either referred to as Spanish bluebells, H. hispanica, or as hybrids between H. non-scripta and H. hispanica.

Aims

To establish whether a detailed morphological analysis can shed light on the taxonomic identity of non-native British bluebells.

Methods

We measured 28 morphological characters and recorded the pollen fertility of native and non-native bluebells in Britain and compared these with H. hispanica populations from Portugal.

Results

British non-native bluebells appeared morphologically close to H. hispanica but occupied a separate phenotypic space. All three taxa showed high morphological variability with overlapping ranges, however, at least 92.8% of trait means were significantly different between any pair-wise taxon comparison. Sixty per cent of continuous traits were significantly larger in British non-native bluebells compared to H. non-scripta and H. hispanica. In contrast, pollen fertility was significantly lower in British non-natives (79%) compared to H. non-scripta (94%) and H. hispanica (84%).

Conclusions

These results are consistent with, however, do not provide conclusive evidence for, the possible hybrid status of British non-native bluebells.

KEYWORDS:

• Bluebells
• Hyacinthoides non-scripta
• Hyacinthoides hispanica
• Spanish bluebell
• hybridisation
• alien
• conservation

Acknowledgements

The authors thank two anonymous reviewers and the Associate Editor for their helpful comments on an earlier version of the manuscript. The Royal Botanic Garden Edinburgh is supported by the Scottish Government’s Rural and Environment Science and Analytical Services Division. The project was supported by funding provided by the Natural History Museum London.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here

Additional information

Notes on contributors

Markus Ruhsam

Markus Ruhsam is a botanist and molecular ecology researcher who uses genetic tools to study and understand plant diversity.

Deborah Kohn

Deborah Kohn is a plant ecologist focused on research supporting conservation.

Jane Squirrell

Jane Squirrell is interested in the ecology and genetics of plants, especially of the British Flora

Harald Schneider

Harald Schneider’s research is focused on the evolutionary history of land plants with special emphasis on the application of macroevolutionary theory to establish more effective methods to conserve plant resources in a rapidly changing world.

Johannes Vogel

Johannes Vogel is General Director. He researches in open and citizen science, public engagement and evolution and biodiversity.

Fred J. Rumsey

Fred Rumsey is a field botanist and herbarium curator with an interest in the history of the British flora and its conservation.

Peter M. Hollingsworth

Pete Hollingsworth is Director of Science and Deputy Keeper. He researches the processes governing the evolution of plant biodiversity and the development of effective strategies to conserve it.