Why bumblebees need our help.

Bumblebees are mainly under threat because of changes to the countryside in the UK. Changes in agricultural techniques have meant that there are far fewer wildflowers in the landscape than there used to be, meaning that many of our bumblebee species are struggling to survive.

The dramatic decline in populations of most species, and the extinction of two species in the UK, show that something needs to be done.

Causes of bumblebee declines
When we think of the British countryside, we often think of rolling green fields with crops or livestock. However, it wasn’t always this way. Until relatively recently, the British landscape was much more colourful. The fields had many more wildflowers, and these supported a much greater diversity of wildlife.

However, technology and demand for increased food production meant that traditional agricultural practises were abandoned in favour of techniques which increased productivity but ultimately reduced the abundance of wildflowers in the countryside. Indeed, it has been estimated that we have lost 97% of our flower-rich grassland since the 1930s. As bees rely entirely upon flowers for food, it is unsurprising that their populations began to rapidly decline in most places.

The result of this has been that two species have become extinct in the UK since the start of the 20th century:

  • Cullem’s bumblebee (Bombus cullumanus), was last recorded in 1941.
  • The Short-haired bumblebee (Bombus subterraneus), was last recorded in 1988.

Both of these species are still found in Europe, but the British populations may have been specially adapted to our climate and environment. Sadly, several other bumblebee species are in trouble, and could become extinct in the UK within a short time. Two species in particular, the Great yellow bumblebee and the Shrill carder bee, are now only present in small numbers.

Impact of bumblebee declines
It is well-known that bumblebees are great pollinators, and therefore have a key role in producing much of the food that we eat. Through the pollination of many commercial crops such as tomatoes, peas, apples and strawberries, insects are estimated to contribute over £400 million per annum to the UK economy and €14.2 billion per annum to the EU economy. If bumblebee and other insect pollinator declines continue, the extremely high cost of pollinating these plants by other means could significantly increase the cost of fruit and vegetables.

Bumblebees also help pollinate many wildflowers, allowing them to reproduce. Without this pollination many of these plants would not produce seeds, resulting in declines in wildflowers. As these plants are often the basis of complex food chains, it is easy to imagine how other wildlife such as other insects, birds and mammals would all suffer if bees disappeared.

 

See the full article at the Bumblebee conservation trust website on this link.

Bumble bees dying

There’s due concern about the fact that bumble bees are dying in the United States as well as other parts of the world. Researchers are baffled by the phenomenon because there seems to be no clear evidence which explains why the population of bumble bees is declining. In the commercial sense, bumble bees in the United States pollinate approximately 15 percent of all crops, which translates to about $3 billion dollars annually. Let’s take a closer look at this mysterious phenomenon.

Over the past 10 to 15 years, four species of bumble bees have been found to suffer alarming population declines of up to 96 percent. These species are Bombus affinis, Bombus occidentalis, Bombus pensylvanicus, and Bombus terricola. According to University of Illinois entomologist Sydney A. Cameron, the geographic range of these species has also declined by about 23 to 87 percent. Some other declining species include the Bombus franklini, Bombus fervidus, Bombus sonorus, and Bombus californicus.

To learn more about bumble bees, it’s necessary to know about their life cycle. Towards the end of autumn, the mated young queen bees search for a safe place to hibernate. The hibernation period extends into spring until the arrival of early warm days. The queens buzz around budding bulbs and flowers to find nectar and pollen, which is turned into honey to be fed to the hatching brood. At this time, the queen will also search for a place to build a nest. The queen begins a new nest by laying eggs into a ball of pollen and wax. After the eggs hatch, the queen adds to the nest while the grubs grow to become worker bees. The worker bees help to build the nest as the queen stays in the nest to lay more eggs. Once summer arrives, the queen lays eggs which would become the next cycle’s queen bees and drones. After mating with the future queens, the drones fly off, leaving the future queens in the mother colony. Towards the end of autumn, the old queen, the drones, and the worker bees would die, leaving the mated young queen bees to hibernate, and begin another cycle.

Some of the known threats to bumble bee populations include climate change, invasive species, habitat destruction, pollution, pesticides, and most significantly, the spread of diseases and pests through the commercial rearing of bumble bees. It’s hypothesized that the shipping of Bombus occidentalis and Bombus impatiens queens to European rearing facilities from 1992 to 1994 resulted in the acquisition of the microsporidian Nosema bombi, a virulent strain common in the European Bombus terrestris. The Nosema bombi fungus was found in a high number of the threatened bumble bee species. Research findings on the DNA of these species revealed that the bees have low genetic diversity which makes them more vulnerable to environmental pressures and other pathogens.

To read the full article go to the Bumblebees dying website on this link

Nicotine based pesticides harm bees

Nicotine-based pesticides harm bees despite corporations’ claims, major study finds amid calls for total ban

Researchers found a 24 per cent reduction in bee populations at test sites in Hungary was linked to use of neonicotinoids, but also some ‘positive’ effects of its use in Germany.

A major £2.7m study into a controversial type of nicotine-based pesticide has found it can cause harm to bees, prompting environmentalists and some scientists to call for an outright ban.

Funded by two major agrochemical companies, the researchers discovered neonicotinoids were associated with negative effects on bees at sites in the UK and Hungary. However, they also found it had some “positive” effects on bees in Germany.

Nevertheless, writing in the leading journal Science, they concluded that the chemicals reduced the ability of bees to establish new populations the following year with a 24 per cent reduction in the Hungarian populations.

Neonics, as they are known, are already the subject of a partial ban by the European Union, which is considering preventing their use completely.

 

See the full article in the The Independent on this link.

How to plant

Prepare the Ground

Bee buffet seeds performs best in low nutrient soils, which haven’t been heavily fertilised in the past. For best results sow into bare soil after clearing all existing plants and weeds from the area.

Cultivate the ground to a depth of 10cm to relieve compaction and create a ne level tilth, free from obstructions (to allow for mowing at a later stage). Finish the seedbed by treading or lightly rolling the area, so that it is rm enough to stand on without leaving indentations.

Where weeds have been prevalent, allow a ush of weeds to germinate and remove these before sowing. In areas of high fertility, it may be necessary to remove the topsoil and sow into the subsoil. High nutrient soils encourage weeds and fast growing grasses which may outcompete the wild owers in this mixture.

Bee buffet can be used to overseed into existing grassland, provided the sward comprises only ne leaved grasses and does not include ryegrass, agricultural species or weeds. Cut the grass as short as possible and thoroughly scarify or rake the ground to remove any thatch, moss and other debris from the area.

Sowing

Bee buffet should be sown between March and November. Spring and autumn provide ideal conditions as moisture and warmth are in good supply. If overseeding into grass, it is best to sow during autumn when grass growth has slowed down.

Distribute seed with a handheld or pedestrian spreader, at the recommended sowing rate of 3g/sqm. Mix the wild flower seeds with an inert carrier (such as sharp sand), at a ratio of four parts sand to one part seed (by weight). This makes it easier to achieve an even distribution and also provides a visual marker, making it easier to see any missed patches and avoid seeding areas twice.

Regularly mix the seed when sowing, as seeds will naturally separate due to variations in size and weight.

Once sown, ensure good ‘seed to soil’ contact by lightly raking to a depth of 0.5cm or rolling the area. When overseeding this encourages the seeds to fall down to the ground underneath.

It is also possible to broadcast, drill or hydroseed this mixture for larger or hard to reach areas. However, broadcast spreading throws heavier seeds further so this may impact the distribution and when drilling, the seed must not be buried deeper than 0.7cm.

Sowing Rate

The sowing rate of 3g/sqm is designed to produce optimum results. Reducing
the sowing rate is likely to result in invasion from weed species. Increasing the sowing rate generally leads to reduced diversity as the more aggressive species will outcompete slower growing plants.

This rate also applies when overseeding into grassland as many seeds may fail to germinate due to the increased competition from the existing grasses, and some seeds not reaching the soil surface.

 

 

Maintenance

First Year

Bee buffet contains mainly perennial species, which can be slow to establish and are unlikely to ower in the rst year. Annual species such as Borage, Corncockle, Corn ower and Field Poppy will generally flower in year one.

During the rst year remove any weeds which grow before they run to seed, either by topping, mowing or by hand for smaller areas. Weed growth is common due to the action of disturbing the ground (rather than being caused by contaminated seed mixtures).

The area can be cut once the owers have died back in the autumn. We recommend leaving the area undisturbed for as long as possible, ideally until February / March (before the rst spring growth). The dead owers and stems provide a diverse environment which is a haven for wildlife through the winter months. In particular, it provides habitat for butter ies such as the Red Admiral and the Clouded Yellow which remain in their chrysalis during the winter months.

Cut the area down to around 10cm using a scythe, strimmer or mower, leaving the cuttings for up to a week before removing. This will allow them to dry and shed seeds back into the soil.

Second Year

After twelve months the sward should be well established and requires little additional maintenance. Simply follow the same annual cut pattern (either in spring or autumn depending on your preference).

As an ongoing process, observe and remove any weeds which invade the area.

Over time, some species within the mixture may become more dominant due to environmental factors and natural selection. To encourage diversity, simply reduce the number of dominant plants in order to restore the balance.