Push to Protect Pollinators Starts at Home
Native plants and native insects are the foundation of a vibrant ecosystem. The system and the ecological services it provides are breaking down.
March 1, 2022
Pollinators, especially bees, play a significant role in maintaining the function and diversity of ecosystems through their unique relationship with native flowering plants. But the ongoing degradation of native pollination systems, coupled with the continued loss of insect biodiversity, pose a significant threat to human health and well-being, and to the world’s future.
As the late biologist and naturalist Edward O. Wilson once said about these vital invertebrates: “If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago. If insects were to vanish, the environment would collapse into chaos.”
Like Wilson, Robert Gegear, assistant professor of biology at the University of Massachusetts Dartmouth, also appreciates the importance of insects. Eight years ago he launched the Beecology Project to learn more about the ecology of native pollinators — the initial focus was on bees, specifically bumblebees — to better understand why some species are doing so poorly while others are thriving, or at least holding steady.
Gegear said certain pollinators are heading toward extinction, such as the rusty patched bumblebee, while others are increasing in numbers, such as the eastern bumblebee.
Overall, though, the news is bleak. Gegear noted there are 52 butterfly species in New England that are in decline.
“Wild pollinators have declined in abundance, diversity, and geographic distribution at an alarming rate over recent years,” according to the opening paragraph on the Beecology Project website. “These declines pose a significant threat to ecosystem health and biodiversity.”
Total insect mass is decreasing by 2.5 percent annually, according to a 2019 study. It points to troubles ahead. Insects are both pollinators and a food source for amphibians, birds, fish, reptiles, and some humans.
More than 40 percent of insect species are declining and a third are endangered, with butterflies and moths among the worst hit, according to the 2019 peer-reviewed scientific paper published in the journal Biological Conservation. The study noted that intensive agriculture is the main driver of insect decline, particularly the overuse of pesticides. Development and the climate crisis only serve to accelerate their demise.
“Unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades,” the study’s authors wrote. “The repercussions this will have for the planet’s ecosystems are catastrophic to say the least.”
One of the problems, among the many, is a lack of information that would allow for the development of effective conservation and restoration strategies for threatened species. How to recreate landscapes, destroyed by relentless building and poisoned by chemicals, that truly support pollinator biodiversity is a complex issue that goes beyond observing insects buzzing for nectar around flowers.
Gegear’s work with the Beecology Project is attempting to fill this knowledge gap, in part by recruiting citizen scientists from across southern New England to digitally collect and submit ecological data on native pollinator species.
In ecology, Gegear said, it is about diversity — not how many individuals there are but how many species there are — because each species has a connection with a flowering plant that has a connection to other species.
Native bees, for instance, have vastly different flower preferences than honeybees, which were imported from Europe.
“The survival of native pollinators has a positive cascading effect on so many other species, both the wild plants they pollinate and the other wildlife using those plants for food, shelter and nest sites,” he told ecoRI News in 2020 in a story with the headline Plight of Pollinators Isn’t Limited to Honeybee Collapse. “Collectively, those relationships are increasing ecosystem health. But as we start to remove pollinators, we start to affect all these other species.”
For example, as species of bumblebees that were once common in southern New England fade, such the yellow-banded bumblebee, the yellow bumblebee, the half-black bumblebee, and the aforementioned rusty patched bumblebee, the impact doesn’t end with their disappearance. The plants they bonded with over centuries also are impacted.
“Some native plants are in decline as well,” Gegear said. “Some of the bees in decline are some of the best pollinators of these plants. We need to rebuild systems.”
Through foraging and natural movements, pollinators, such as bees, beetles and butterflies, transfer pollen, allowing the fertilization and subsequent fruiting of trees and plants.
Of all flowering plants, 85 percent require an animal — mostly insects, but also vertebrates such as birds and bats — to transfer pollen. Pollinators also account for the fertilization of some 35 percent of crop production worldwide, with a value of nearly $220 billion annually.
The part of the pollinator/plant/animal biodiversity decline that goes largely unnoticed, however, is the impact on ecosystem services. Interactions between native species, which have co-evolved for millenniums, support the sequestration of carbon, soil decomposition, and water purification. Their significance goes way beyond food production.
“We are getting these services for free, but because of a massive reduction in biodiversity we are losing these services,” said Gegear, whose work focuses on restoring the functional role of pollinators and studying animal-flower interactions. “Once we lose this stuff, we’re not getting it back. We cannot replicate these services and systems.”
While many home gardeners want to help support pollinator biodiversity, Gegear noted data are still being gathered to inform them on what they should be planting, especially when it comes to attracting bumblebees. The Beecology Project has already provided some answers.
Using eight years of live surveys, observations and other research techniques — much of it obtained on a 40-acre parcel of conserved land in Southborough and at Gegear’s outside laboratory in Dartmouth — the UMass professor and his team have created a list of native plants that support local bumblebee species at risk, as well as other bee species and butterflies. (The list is for Massachusetts, but Gegear said it can also be mostly applied to Rhode Island and Connecticut.)
The preference of pollinators varies by species, but, in general, native insects prefer native plants. That relationship, though, is much more complicated than that simple premise. It can take a variety of plants to support one pollinator species, as many insects require a host plant plus sources for nectar and pollen. Those three needs aren’t typically provided by a single plant species.
The needs within a species can also be varied. For instance, short-tongued bees are attracted to cup-shaped flowers, while long-tongued bees prefer tubular ones. The preference of medium-tongued bees falls somewhere in between. Gegear said many residential and commercial landscapes lack tubular flowers.
At both the Southborough and Dartmouth sites, where native plants of all shapes and sizes have been planted, Gegear said the reintroduction of a diverse collection of native plantings has resulted in the emergence of pollinators and birds, such as the white-throated sparrow, that are regionally in decline.
As Gegear and his research team continue to discover what native plants support what native insects, there are things concerned backyard gardeners can do now to help protect and restore native pollination systems and the ecosystems they support: plant native species; replace lawns with meadows and gardens; and lay off the use of pesticides and herbicides.
Gegear offered tips for home gardeners interested in supporting pollinators:
Select nectar and pollen plants so there are blooms in every season (March-May) (June-July) (August-September).
Spring floral resources are important for at-risk pollinators, so give them a high priority.
Be aware that in most cases, the species of a plant is far more beneficial to pollinators than named cultivars.
Select plants that target as many species of pollinators as possible, as a good habitat will support species at risk over the entire season.
Leave some soil bare for ground-nesting bees.
The National Audubon Society also offers some suggestions to support and encourage the diversity and health of pollinators:
Go natural with your lawn. Allow flowers such as clover and dandelions to grow.
Select native New England flowering plants and bushes. Use pollen-producing plants in planters and on apartment balconies. (While eastern bumblebees are attracted to non-native plants, other bumblebees don’t like foreign varieties.)
Refrain from clearing leaf litter and cutting old plant stalks as insects lay their eggs in these and use them for overwintering shelter.
Leave dead trees on your property, as many pollinators use decaying trees to lay their eggs and pupate into adults.