Habitat loss is a significant threat to bee populations worldwide, but how does it affect bees and their ability to thrive?
From residential expansion to increases in agricultural productivity, thousands of bee species are suffering a population decline and hundreds are at risk of extinction.
Understanding how habitat loss will affect bees is the key to ensuring we can protect them and prevent the extinction of any more species.
The good news is that habitat loss and how it can affect bees do not have to be permanent. There are lots of things we can do to reverse the decline of bee populations from the comfort of our own homes.
Causes of Habitat Loss
- climate change (disruption of temperature and weather cycles)
- land repurposed for grazing
- land clearance for building or extending new roads
When it comes to identifying the causes of habitat loss for bees, humans are by far the biggest culprits.
Whether it is digging up land to extend our road networks or felling trees and hedgerows to make way for more housing, our actions are decimating bee habitats at an alarming rate.
Habitat loss affects bees in many different ways, but most of their problems can be resolved or reversed with simple and dedicated conservation efforts.
Colony Collapse Disorder
The phenomenon of Colony Collapse Disorder (CCD) occurs when a seemingly healthy adult colony suddenly abandons the hive or dies off, leaving the queen and young. CCD was first reported in North America in 2006, with beekeepers recording losses of up to 90%.
The cause of this phenomenon is unknown, but experts believe they have narrowed the list to a handful of possibilities. Changes to the foraging habitats of bees is a key area of focus, as well as pesticide poisoning, gut parasites, and diseases such as the Israeli Acute Paralysis Virus.
Habitat fragmentation is the separating of a single habitat area into smaller fragments. Building roads, railway lines, and infrastructure are major causes of bee habitat fragmentation.
A 2017 study conducted in Arizona found that habitat fragmentation affected both the nesting requirements and food sources of native solitary bee species.
A similar study published this week reported that creating habitat corridors has a positive effect on nest site occupation, which is a huge step forward in future bee conservation.
Habitat fragmentation can cause further disruption to bee populations, such as:
- Decrease of genetic diversity
- Nutritional stress
Since bee populations become fragmented, the genetic diversity falls dramatically, leading to colonies with weaker immune systems and at greater risk of diseases and deformities.
Additionally, areas for foraging are greatly reduced, causing nutritional stress, poor overall diet, or even a lack of food.
Nests and man-made hives in small habitat fragments are at much higher risk from predators compared to bee populations in larger or unobstructed habitats.
Badgers, a species that seems to fair quite well in fragmented urban areas, is one of the main predators of the bumblebee.
With predator species less affected by habitat fragmentation, bee species in small habitat fragments face greater threats than colonies in larger habitats.
Habitat Loss and Nesting
While domestic bees living in man-made hives already have a safe nesting area, wild bee colonies need a high resource habitat to build their nests. Let’s take the humble honeybee as an example.
To begin construction, honeybees must collect a resin from tree buds called Propolis.
This substance has several uses within the nest, but its main use is as a sealant to fill any crevices as the honeycomb structure is built. Without deciduous trees that produce Propolis, honeybees cannot construct a suitable nest for the colony.
When scouting for new nest sites, bees look for three key factors:
- A tree that provides suitable coverage from the elements.
- A location where the nest will have only one entrance and exit.
- A deciduous tree that produces Propolis from its tree buds.
Once a good site has been identified, that bee will communicate its finding to the rest of the colony by performing a “waggle dance”. This involves a series of movements and body vibrations that tell the other bees where to go.
Without these important features, the colony will not build a new nest. This means they cannot protect the colony and they will be unable to reproduce or feed the queen and larvae.
Pollen and Nectar
Many people underestimate the importance of pollen and nectar for bee colonies. Nectar is a sweet substance produced by flowers that bees consume as an energy source.
Drinking nectar ensures bees have the strength to go about their foraging routine and return to the nest with their haul. Whilst a bee is collecting nectar from a flower, pollen will collect on its furry body and legs.
Each flower a bee visits will be pollinated by that same bee. Pollen is also vital for the survival of larvae. They need bee pollen, which is a mixture of pollen and various proteins that adult bees produce.
Bees and flowers have a symbiotic relationship. One cannot survive without the other. Bees need flowers as a source of nectar and pollen, flowers need bees in order to reproduce (pollination).
A flower cannot simply get up and go looking for a mate!
Unfortunately for bee colonies, many wildflower meadows that bees use as foraging sites are destroyed or fragmented by construction work for housing, shopping, and office buildings, the extension of the road and railway networks, and the expansion of agricultural land.
Habitat Loss Due To Climate Change
One of the most disorientating ways bees can be affected is the change of a flower’s scent due to climate change.
Bees are able to recall from memory the unique scents of the flowers they visit so they recognise the flowers with the best sources of nectar via their distinguishing smell.
This is due to plant stress caused by changes to environmental conditions.
This could fluctuate in heat or the availability of water. Stressed plants release compounds as a defence mechanism and this is what alters their scent, meaning bees can easily confuse them.
Bees also use the scents of each flower as a guide from the nest to their food sources. If this changes, bees are unable to food enough food to sustain the colony.
Climate change also has a significant effect on the time between flowers producing pollen and bees coming out of their winter hibernation.
Bees usually time their spring waking with the first bloom of flowers, but climate change has affected this synchronicity, meaning the bees are losing that vital first bloom and production of pollen.
Not only does this reduce the availability of food for bees, but it also decreases the amount of plant pollination.
Extinct and Endangered Species Due To Habitat Loss
In North America there are two endangered bee species:
- Yellow Faced Bee (7 species) native to Hawaii, listed as endangered in 2016
- Rusty Patched Bumblebee, US East Coast and Canada, listed as endangered 2017
The seven species of Yellow Faced bees receive federal protection under the Endangered Species Act of 1973. They are responsible for pollinating many crops on the island including Pumpkin and Watermelon.
These crops are dependent on bees and will not produce fruits if there is inadequate bee visitation. Bees are responsible for pollinating a wide range of fruit consumed by humans.
As of 2019, Northern Ireland has 21 species at risk of extinction, while the UK has seen the regional extinction of 17 bee species, including the Great Yellow Bumblebee and the Potter Flower Bee. A further 25 UK bee species under threat including:
- Moss Carder bee
- Shrill Carder bee
- Sea Aster colletes
Bee Conservation: How Can We Repair The Effects of Habitat Loss?
We can each do our part to protect and conserve our local bee populations and to reduce the effects of habitat loss. Gardening, pesticide alternatives, and buying local, organic produce all go a long way towards supporting local bee species.
Creating a bee-friendly garden is super simple and will provide the perfect foraging habitat for bees. You can do this by planting nectar-rich plants such as Crocus, Bluebell, and Honeysuckle. Sunflowers are a favorite for honeybees, while bumblebees love wild strawberry flowers. Lavender is ideal for a bee garden.
Not only does it produce lots of nectar and pollen, but it also keeps the nest healthy by preventing bacterial growth. Other herbs like Thyme and Oregano will help to prevent the spread of mites within the colony.
Let your perennials like Dandelion grow wild! Having an area that you allow to grow naturally will create the perfect foraging zones. To control weeds in other areas of your garden, use mulch rather than chemical pesticides.
If you prefer a neat, manicured garden, you can plant flowers along the borders of your lawn. Try to include a variety of different colors and heights for greater diversity.
Purchasing organic produce means that you are supporting farmers who do not use pesticides. Such chemicals are harmful to bees and other pollinating insects. Find your local farmer’s market or seek out pesticide-free fruits and vegetables in the supermarket.
On a larger scale, protecting nesting and foraging areas of wild bee species is key to successful conservation efforts. This includes marshes, grasslands, and coastal areas with lots of wildflowers and deciduous trees which provide plentiful nectar, pollen, and viable nest sites.
Increasing the number of new trees planted will also have an impact on the number of suitable nest sites, as most bee species prefer to nest in trees that provide coverage from the sun and produce essential Propolis from their buds.