Local Pollinators Face Mounting Survival Challenges

By ecoRI News staff

Of all flowering plants, 85 percent require an animal, mostly insects, to transfer pollen for fertilization. (Audubon Society of Rhode Island)

Of all flowering plants, 85 percent require an animal, mostly insects, to transfer pollen for fertilization. (Audubon Society of Rhode Island)

Pollinators are vital to the health of natural food chains and the functioning of ecosystems. They are also often the key to agricultural success. Through foraging and natural movements, pollinators — invertebrates such as bees, butterflies and beetles, and vertebrates such as bats and birds — transfer pollen, allowing the fertilization and subsequent fruiting of trees and plants.

Of all flowering plants, 85 percent require an animal — mostly insects — to transfer pollen for fertilization. Pollinators account for the fertilization of 35 percent of crop production worldwide, with a value of $217 billion annually. Both European honeybees and the 3,500 species of native bees account for most of agricultural pollination. Their bodies are designed to attract the electrostatically charged pollen with their bristly thorax and hairy “pollen baskets” on their legs.

Since the 1950s, however, there has been a 50 percent decline in managed honeybee hives, according to the Audubon Society. Wild hives have fared even worse. Nearly 17percent of vertebrate pollinators and more than 40 percent of invertebrate pollinators are facing the threat of extinction.

Also, more than 140 species of butterflies in North America are at risk, while monarch butterflies alone have declined by 90 percent during the past two decades, according to the Audubon Society.

The Audubon Society offers some reasons as to why is this happening:

Pesticide exposure. Heavy pesticide use in agriculture and landscaping shows direct correlation to declines in all insects, especially bees. The synergistic effects of pesticides aren’t well understood and the application of different pesticides on the same property may intensify toxicity to pollinators.

Changes in land use. Natural habitats and open space are being lost to development. In the past eight years, more than 8 million acres of former farmland and natural space has been paved or developed. Urbanization reduces nesting habitat for bees and limits the floral resources they require for food.

Invasive species. As foreign species of plants, insects, fungi and bacteria become introduced, they alter and interfere with the proper functioning of ecosystems by pushing out native species, changing the availability of food resources, and introducing diseases for which endemic species have no defense.

Pathogens, parasites and disease. Honeybees have been hard hit hard by diseases and varroa mite infestations. Colony collapse disorder has impacted bees worldwide, and the causes are still being investigated.

Climate change. Weather patterns are becoming more extreme, growing seasons are altering, and average temperatures are warming. For pollinators, climate change affects food sources that may not be available at times when they are expected and needed.

Changes in agricultural methods. Bees need a diversity of plants that flower throughout the growing season. Small farms and gardens that supplied diverse crops are in steep decline. This has resulted in reduced nutrition for bees. They are also less likely to bounce back from environmental crises such as drought and floods. The loss of field borders and scrubland also means less habitat for native bees.

The Audubon Society offers some tips to support and encourage the diversity and health of pollinators:

Go natural with your lawn. Allow flowers such as clover and dandelions to grow. Minimize or eliminate the use of pesticides.

Select native New England flowering plants and bushes. Use pollen-producing plants in planters and on apartment balconies.

Refrain from clearing leaf litter and old plant stalks in spring as bees lay their eggs in these.

Minimize or eliminate pesticide use in your gardens. Predatory insects will come for those beetles and cutworms. Garden plants can tolerate a little bit of defoliation without much harm.

Leave dead trees on your property, as many pollinators use decaying trees to lay their eggs and pupate into adults.  Bumblebees use brush piles, old burrows and tree cavities for nests.

The Audubon Environmental Education Center in Bristol, R.I., will be holding several events during National Pollinator Week, June 19-25. Here are some of the events scheduled: June 20: Enhancing pollinator habitat lecture, 7-8 p.m.; June 21: Screening of the film “Hometown Habitat: Stories of Bringing Nature Home, 7-8:30 p.m.; June 25, Insect Investigation for Families, 11 a.m.-noon.