Improving sea wall habitats for rare bumblebees

This week I caught up with our Conservation Officer for east England, Sam Page. Over the last seven months, Sam Page, has been working with the Environment Agency to look at ways the sea wall flood defences on the Hoo Peninsula in North Kent can be managed more sensitively for bumblebees.  Read on to see what Sam's been up to.

Sea walls are a valuable habitat for wildlife, often supporting rare plants and insects.  While some sea defences are hard-surfaced, most are earth banks covered in flower-rich unimproved grassland.  These continuous strips of habitat also act as important wildlife corridors, enabling species to disperse along extensive stretches of coast.

In North Kent, several rare bumblebees are associated with the sea wall habitat – including the Shrill carder bee Bombus sylvarum, Brown-banded carder bee, Bombus humili,s and Moss carder bee, Bombus muscorum.  The shrill carder bee is one of the rarest bumblebees in the UK, with only six or seven surviving metapopulations, one of which is in the Thames Gateway (North Kent/South Essex) – so Sam is working with farmers and landowners in the area to conserve this and other rare bumblebees.

Sea walls are, first and foremost, flood defence structures, so the Environment Agency (EA) has a responsibility to monitor and maintain them to a high standard.  This involves mowing the sea wall regularly, often during the summer, which unfortunately means removing essential sources of pollen and nectar just when our bumblebees most need them!  Sam has therefore been working with the EA (and Natural England) to explore ways in which the sea wall cutting regime can be adjusted to ensure that at least some of these flower-rich strips remain uncut during the summer months.

The good news is that the EA has now agreed to 16.8km ‘bumblebee priority sections’ on the Hoo Peninsula where the sea wall is going to be cut in early April (before our rare bumblebees have emerged from hibernation) and then again in late September or October, therefore ensuring that flowers will be available during the summer months.  In addition, the EA have agreed to manage the flat ‘berm’ area (between the sea wall and borrowdyke) along 50km of sea wall habitat on a rotational cutting system to benefit bumblebees.  The berm often supports important forage plants such as red clover, Trifolium pratense, and narrow-leaved bird’s-foot-trefoil, Lotus glaber, which are particularly favoured by the rare longer-tongued carder bees.  This rotational cutting system will help retain and increase the amount of forage for bumblebees and other insects, as well as ensuring some of the berm grassland is left undisturbed to provide bumblebee nesting habitat.                

So, all in all, a good result for our rare bumblebees!  The Bumblebee Conservation Trust will now be working closely with the EA to monitor these changes and will be carrying out regular bumblebee surveys to help inform future management of the sea walls here and elsewhere in North Kent.

Brown-banded carder bee on red clover, Hoo Peninsula (Photo: Sam Page)

  Flower-rich sea wall habitat, Hoo Peninsula, North Kent (Photo: Paul Larkin)

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