The importance of flowering ivy in autumn

ivyOriginally written in October 2015.

Ivy, Hedera helix, is a common sight in woodlands and gardens across Britain. The younger leaves display the characteristic triangular shape, whereas the older leaves are more rounded in appearance. As a woody climber this species is often seen wrapped around trees, fences and buildings, occasionally much to the homeowner’s annoyance. It is however the flowering time of this species, from September to November, that makes it a vital component of the ecosystem.

The ivy’s late flowering means it is one of the last plants available for insects to benefit from before the winter. A Sussex study by Garbuzov and Ratnieks (2014), showed that a large amount of pollen pellets gathered by honey bees throughout the autumn period came from ivy, on average 89%. Furthermore by observing the behaviour of the honey bees visiting the plants they ascertained that 80% of the bees were gathering just ivy nectar, which is around 49% sugar, showing it was valued more than pollen. Garbuzov and Ratnieks further highlighted the importance of ivy for a variety of insects, recording honey bees, bumble bees, common wasps, butterflies, hover flies and other fly species foraging on the flowers. This suggests that ivy is a keystone species.

Ivy provides a vital resource for insects towards the end of the flowering season when resources are decreasing. This is especially important for insects about to go into hibernation, as it will aid their survival through the colder months allowing them to emerge again the next year. This is particularly significant as insects are vital pollinators in the UK, worth around £440 million each year to the UK agricultural industry (DEFRA, 2011). Furthermore many insect populations have declined, such as the reduction in England of honey bee colony numbers, around 54% in 20 years (DEFRA, 2011).

Ivy also produces berries, an important food source for birds during winter when other berries are less abundant. This plant is a species which is often overlooked but plays a vital role in the ecosystem, especially during the autumn months. Therefore by leaving ivy growing in your garden you are making an important contribution to helping species survive the colder months of the year.

References

DEFRA. (2011) The Natural Choice: Securing the value of nature. London: TSO.

Garbuzov, M.  and Ratnieks, F. (2014) ‘Ivy: An underappreciated key resource to flower-visiting insects in autumn’, Insect Conservation and Diversity7, (1), 91-102.

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