Nature Notes: Pollinators
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By Ed Robinson
We all love to see colorful flowers and shrubs in our gardens at this time of year. Mary and I always look forward to our crab apple tree blossoming bright pink, followed by the lilacs with their heavenly scent and tiny drops of sweet nectar. The planting of such species, and many other flowering plants doesn’t just add beauty to our lives. It is also vital to the life cycles of some important creatures in our world and has a big impact on the food chain upon which we depend.
I am referring to the various species known as “pollinators,” who are the creatures that move pollen from the male parts of a flower (called the “anthers”) to the female parts (“stigma”) to accomplish plant fertilization. Some plants are self-pollinating, with the wind lending a helping hand, but others require active assistance to move pollen from one plant to another. There is even a branch of science known as “anthecology” for those who study pollination.
Many of us think of bees and hummingbirds as important pollinators, but I was surprised to learn how many other species also serve to move pollen about. There are hundreds of different bees and wasps, plus ants and other crawling insects. Bee flies and hoverflies make the list, along with flower beetles and various moths. Bats, honeyeaters and sunbirds have long beaks to sip nectar from deep-throated flowers, and even creatures like monkeys, possums and rodents can play a role in this pollen game. Let’s not forget some of the loveliest pollinators around: the butterflies of all shapes, sizes and colors.
Each type of flowering plant tends to attract specific pollinators, either because of the color of the blossom, its size and shape, or the amount of pollen or nectar available. This serves to reduce competition among the pollinators. But if there is a population drop among the preferred pollinator, then the plant in question may suffer declines in productivity or numbers. The corollary is that when the population of a particular plant falls, that impacts the population of pollinators that depend upon the flower for nutrition.
So why is this an important topic? It has been estimated that more than 1,000 plants grown for food, fibers, spices, medicines and beverages require pollination in order to produce the goods we require. This is obvious when you think of apples, but it also applies to our beloved blueberries, chocolate, coffee, melons, potatoes, pumpkins, vanilla, almonds and tequila. The Pollinator Partnership estimates that the value of pollinated crops produced annually in the USA exceeds $40 billion. I have seen other estimates that as much as 70 percent of the food we eat is dependent in some manner upon proper pollination.
The problem, of course, is that many species of pollinators have been in decline over the last few decades. Honey bees have suffered from loss of habitat, pollution, pesticides and viruses. Despite growing numbers of managed bee hives outside the USA, we have lost more than 50 percent of our honey bees, and many more wild bees have been lost. Bat populations have plummeted due to white nose syndrome, and some species like the Franklin’s bumble bee are in danger of extinction. We all enjoy seeing monarch butterflies in the late summer, but wild populations of milkweed plants, the key plant for monarch feeding during their long migrations to and from Mexico, have been falling, and so goes the monarch.
Environmental groups have lobbied the US Environmental Protection Agency (EPA) to ban certain pesticides, particularly the family known as neonicotinoids. In May of last year, the Obama administration released the National Strategy to Promote the Health of Honey Bees and Other Pollinators. In Europe, the EU committed $20 million to study the populations of wild pollinators. Some chemical companies are now voluntarily removing neonicotinoids from the market, and on May 31, Maryland became the first state to ban their use starting in mid-2018.
So this begs the question – what can we do to help out? The first step is to grow more flowering plants, ideally a variety of them to help a range of pollinators. Done properly, this means you will have plants in bloom all season long. Many seed catalogs and websites can help you, but try the National Wildlife Federation for information, ideas and seeds. LiveMonarch.com is reputed to be a good source for milkweed seeds if you want to help the monarch butterfly. There is a push to plant milkweed from one end of the country to the other so that monarchs have food sources along the entire path of their migration. Make sure you choose native plants. These are the plants our local pollinators depend on.
It is important to restrain your use of pesticides and herbicides, since they can have an impact far beyond the targeted insects or plants you hope to control. In Harpswell, it is also important to avoid allowing harsh chemicals into runoff water that enters the ocean. If you can delay mowing or cutting flowering plants in fields or brushy areas until autumn, this extends the availability of blossoms for pollinators.
Working under a USDA contract called the Conservation Stewardship Program (CSP), I have received funding so that I could plant two pollinator plots of one acre each at our old farm in New York. After removing as much of the existing vegetation as possible, I lightly worked up the soil and planted more than 15 different species in each plot. The goal was to have at least three species that blossom early in the season, three mid-season bloomers, and three that bloom late. My list is extensive, and includes lavender, purple bergamot, milkweed, lupine, mountain mint, asters, spiderwort, sunflowers, goldenrod, ironweed, boneset, red and white clover and more. The seeds can be quite expensive, so pick carefully.
It was hard work getting the pollinator plots in place, but after a year of growth, there is now a diversity of flowering plants well beyond that which existed previously. During a two week stay last August, I was amazed at how many butterflies and other creatures were taking advantage of the pollen available to them. Not only was our field alive with color and delightful scents, but some of nature’s most delicate creatures were given a helping hand to thrive in a challenging world.