Minerals sites offer excellent opportunities to provide habitat and foraging (feeding) opportunities for many of the twenty four species of bumblebee in the UK.  They are hard working and versatile pollinators of both agricultural crops and many wildflower species.  Bumblebees have been declining due to the widespread loss of wildflower grasslands and changes in agricultural practice. Nine species are thought to have considerably declined in range and two have become extinct in the last sixty years.

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Key Points

  • Bumblebees need consistent flower rich habitat from late February to October - throughout the life of the colony.  They only store a few days food in the nest at a time and the nest will not produce new queens if food is scarce.
  • Bees need nectar to provide energy and pollen to provide protein for larval development.
  • Bumblebees have different tongue lengths so need a range of flower shapes to feed from.
  • Short tongue bees like open flowers e.g. fruit trees, bramble, knapweed
  • Long tongued bumblebees favour plants from the figwort family (eg: red bartsia, toadflax), the legume family (eg: red clover, tufted vetch, bird’s foot trefoil), the teasel family (e.g. field scabious, devil’s-bit scabious), the daisy family (e.g. knapweed) and the dead nettle family (eg: white dead nettle, hedge woundwort, black horehound)
  • Bumblebees nest in rough grassland, field margins or hedge banks. Some species nest underground in old mouse or vole holes, while other species create a nest at the base of tussocky grass.
  • Bumblebees will forage between 1 – 2km from the nest to find food. Ideally nesting habitat should be close to good pollen and nectar sources.

Key Measures

  • Identify areas where appropriate to create of new flower rich habitats.  Consider re-seeding top soil bunds with native wildflowers or the use of agricultural pollen and nectar mixes on farmland.   Seed addition can also be used to diversify existing grasslands.  Cultivation is needed to prepare the ground and minimise soil compaction.
  • Key bumblebee plants include red clover, yellow rattle, birds-foot trefoil, kidney vetch, and heather. A number of seed companies supply native wildflower seeds and can advise and provide suitable species and seed mixes based on for the site soil type and conditions. Information on sourcing wildflower seed for bumblebees can be found via https://www.bumblebeeconservation.org/
  • Manage existing grasslands to keep the habitat open and prevent encroachment from scrub and rank grasses. This can be achieved through cutting and collecting, grazing, and scrub control with selective herbicides. Rabbit grazing on restored quarries can also help if levels are not too high.
  • If existing grassland is missing key species after several years then selective addition of plants with seed or plug plants is an option.
  • Retain areas of ruderal vegetation (plants that thrive on disturbed ground) such as gorse, willowherb and bramble. These are good nectar and pollen sources for bumblebees.

Providing for bumblebees in restoration schemes

  • Aim to restore and re-create the priority semi natural habitats appropriate to the quarry site based on location, climate, aspect and soil type. Restoration should link to the surrounding landscape and connect or buffer existing high quality habitats.
  • Include varied topography in restoration design to create warm, south facing, sheltered microclimates that will benefit a range of invertebrates including bees.  Re-create terraced slopes of varying degrees. Bare cliffs and steep sides with shallow substrates will maintain areas of bare soil and provide excellent nesting sites for burrowing solitary bees and wasps.
  • Replacement topsoil is not always needed, new habitats can establish directly on the substrate. If topsoil from diverse grassland has been retained prior to quarrying, this can be spread thinly during restoration to help re-establishment from the seed bank. Consider habitat creation using green hay where this is an option.
  • Natural regeneration of bare substrates can produce valuable pioneer grassland communities appropriate to local conditions.  Mineral nutrient stress allows high wildflower diversity in place of competitive grasses and scrub. Colonising plants including birds-foot trefoil, kidney vetch, horseshoe vetch and common fleabane are valuable nectar and pollen sources.  Small scale rotational scrapping of the substrate can help create a mosaic of bare ground and early successional vegetation. Allow areas of natural regeneration time to develop before considering seed addition.
  • Where sites are being restored to woodland, design in woodland glades and rides to provide good ground flora including primrose, bluebell and ground ivy.  Include flowering shrubs in new woodlands and hedgerows such as crab apple, wild cherry, sallow, honeysuckle and dog rose.

Seasonal Requirements

Spring

It is important to provide pollen and nectar in spring when the queen bumblebees are emerging from hibernation and need to build up reserves of energy quickly. Plants include Bluebell, Bugle, White dead nettle, Erica (heather) and Pussy willow.

Summer

If cutting and collecting from grassland in mid summer then aim to leave a field or buffer strips that are left uncut or not cut until October to provide late forage. Rotate the late cut areas around the site each year.

 Late Summer – Autumn

Late forage availability in September/October is essential for rarer bumblebee species to complete their life cycle. Encourage late flowering plants such as scabious, knapweed and red bartsia

More information

BBCT can provide site specific land management advice and further guidance on choice of wildflower or pollen and nectar mixes to support bumblebees. Please contact advice@bumblebeeconservation.org.uk

 

There are a range of land management factsheets available on the Bumblebee Conservation Trust Website

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