Diadasia sp. bee in a prickly pear cactus flower. Bees in this group forage exclusively on a small number of native North American desert-dwelling plants.
PHOTO CREDIT: Heather Broccard-Bell
Happy Earth Day! To celebrate, I want to spend this post exploring the important role pollinators, including honey bees, play in maintaining healthy ecosystems. Along the way, I’ll get into what healthy ecosystems are, and why they are valuable. And I’ll finish by providing some tips on things we as beekeepers and gardeners can do to help pollinators keep pollinating.
Primary Producers: Supporting All Life on Earth
Every living thing is part of an interconnected network of organisms and non-living things (e.g., weather; geography) known as an ecosystem. All ecosystems rely on populations of organisms called primary producers to convert inorganic material — energy from the sun in most cases — into food for everything else in the ecosystem. Without primary producers, there would be no life on Earth.
Producers and Consumers
In terms of biomass, plants are the most important primary producers on land. Most land plants are flowering plants. As you may recall from my earlier post, pollination by insects and other creatures is one of the main ways flowering plants reproduce. It is estimated that 87.5% of flowering plant species require animals for pollination.
Pollinators need plant products (e.g., nectar; pollen) for food. Hence, pollinators are primary consumers. A host of animals eat pollinators, including the aptly-named Bee-eater birds.1 Many creatures routinely dine on the literal fruits of pollinator labour – not to mention, on other plant parts, such as leaves. Finally, flowering plants themselves are important habitats for other organisms. For example, a single tree in Costa Rica was found to harbour 126 distinct plant species alone.
Bernardino Blue (Eupholites bernardino) on California Buckwheat (Eriogonum fasciculatum). Both adults and larvae feed exclusively on plants in the Eriogonum genus (Buckwheats).
PHOTO CREDIT: Heather Broccard-Bell
Pollinators and Agriculture
The western honey bee (Apis mellifera) does a good job of pollinating most flowering plant crops, but there are some exceptions. For example, leafcutter bees (Megachile spp.) are better at pollinating peculiarly-shaped alfalfa flowers. Brazil nuts require pollination by large-bodied bees, such as bumble bees (Bombus spp.), orchard bees (Osmia spp.), or carpenter bees (Xylocopa spp.). Fig trees need the help of specialized fig wasps (Chalcidoidea spp.) to produce fruit. And honey bees do not tolerate greenhouses well; hence, indoor agriculture relies heavily on bumble bees.
Bees – both wild and managed – are widely considered to be the most important agricultural pollinators. However, contributions from non-bee pollinators are not insignificant. For instance, one group estimated that non-bee species are responsible for approximately 39% of floral visits on crop species globally. In total, pollination of crops by animals is estimated to contribute an additional USD 235–577 billion annually to the global economy. But the positive impact of pollinators extends well beyond boosting the economy and helping to produce the foods we eat.
Leafcutter bee (Megachile sp.) on Vetch (Vicia sp.). Included in the Megachile genus is the economically important Megachile rotundata – the Alfalfa leafcutter bee – widely used for crop pollination.
PHOTO CREDIT: Heather Broccard-Bell
Plants and Pollinators Promote Healthy Ecosystems
A healthy ecosystem is biodiverse — that is, it includes a large number of different species. In general, as an ecosystem has more species, the fate of the ecosystem is less likely to be tied to any one species. So, unexpected environmental changes that might be bad for an individual species are less likely to have a negative impact on the whole ecosystem.
As we learned, pollinators and flowering plants are interdependent. As the number of pollinator species increases, the number of plant species they can support — and be supported by — also increases. And because of their pivotal role as primary producers, as the number of plant species goes up, the number of species of all other types of organism in the ecosystem can also expand.2
Female Valley Carpenter Bee (Xylocopa sonorina). These large bees are often mistaken for bumble bees – especially the males, which are often have yellow stripes.
PHOTO CREDIT: Heather Broccard-Bell
Biodiversity Benefits Everyone
Diverse ecosystems are wonders of nature, worthy of awe for their own sake. But biodiversity also benefits humans in many more tangible ways. Here are two important ones:
The original source of many of our medicines, the natural world produces a cornucopia of useful pharmaceutical substances. Even today, new and promising compounds are being discovered all the time. Loss of biodiversity means that useful medicinal plants, fungi, and other organisms could go extinct before they are ever even discovered. After all, conservative estimates suggest that only 10-20% of species on Earth have been described!
Living things can also be used to repair damaged environments, processes known as bioremediation and bioaugmentation. For example, some plants, bacteria, and seaweeds have the capacity to remove or degrade heavy metals and other toxins from contaminated land and water. Not only does this benefit humans, bioremediation and bioaugmentation themselves can foster greater biodiversity by opening up previously unusable habitat. As was the case with medicinal organisms, it is likely that a vast number of environmentally beneficial organisms remain undiscovered.
What Can We Do to Promote Biodiversity?
Now that you know a little bit about what biodiversity is and why it’s important, here are some things to keep in mind as you are keeping your bees and tending your gardens. Many of you are likely already doing some or all of these things already!
Geron sp. beefly. This bee-mimic is in fact, not a bee – but is a great pollinator!
PHOTO CREDIT: Heather Broccard-Bell
Pollinator-Friendly Beekeeping Tips
- Maintain low stocking densities of honey bees. If you’re a honey producer, you already know that having too many honey bee colonies in too small an area reduces the performance of your colonies. It is a fundamental fact of nature that only so much forage is available for any given environment. Honey bees can compete with native pollinators for food sources, so we need to ensure that there is enough forage for everyone.
- Reduce off-target effects of chemicals used in beekeeping. When applying synthetic or organic treatments for diseases in your colonies, ensure you use only registered treatments, and follow the label directions precisely. Registered treatments undergo extensive testing the world over – including assessments of environmental effects. However, these assessments are conducted per the manufacturer’s application instructions. Improperly applied products, because they have never been tested under such conditions, have unknown effects on the environment, including non-target organisms.
Pollinator-Friendly Gardening
- Whenever possible, grow plants that are native to your region. Not only does this help support native pollinators, it also reduces the likelihood of accidentally spreading invasive species that can disrupt local ecosystems.
- Reduce your dependence on pesticides. These days, nurseries will often indicate whether their plants have been treated with pesticides. Because pest species are often closely related to beneficial species, many pesticides, including some organic pesticides, can cause harm to pollinators.
- Reduce mowing your lawn, especially in spring. As people become more educated on the importance of pollinators, No Mow May / Low Mow Spring is quickly catching on. Leaf litter and old stems provide valuable habitat in which pollinators overwinter. Many pollinators breed on or near the ground in the spring, so leaving these areas undisturbed early in the year can help to boost their populations.
Footnotes
[1] Note that Bee-eaters do not focus exclusively on bees, and have been known to eat a wide range of flying insects.
[2] Just because biodiversity can increase, doesn’t always mean that it will increase. Biology is notoriously complicated and sensitive to local conditions.
