Pollinators’ Decline Called Threat to Crops

Today’s Washington Post has an article on pollinators, in rapid decline in many areas of the world.

Birds, bees, bats and other species that pollinate North American plant life are losing population, according to a study released yesterday by the National Research Council. This “demonstrably downward” trend could damage dozens of commercially important crops, scientists warned, since three-quarters of all flowering plants depend on pollinators for fertilization.

Important to both farmers and ecosystems:

“Canadian black bears need blueberries, and the blueberries need bees” for pollination, [Peter] Kevan [professor at the University of Guelph, Ontario] said. “Without the bees you don’t have blueberries, and without the blueberries you don’t have black bears.”

The article suggested some reasons for the plummeting levels of pollinators:

A number of factors have cut pollinators’ numbers in recent decades, the researchers said. Introduced parasites such as the varroa mite have hurt the honeybee population, and pesticides have also taken a toll. Bats, which carry pollen to a variety of crops, have declined as vandalism and development have destroyed some of their key cave roosts.

There are other problems I’ve seen in various articles: one prediction of global warming models is that the climate will change to fewer seasons/days we call normal (normal is changing) and more we call extreme. Many insects cannot adapt to the increase in extremes now occurring, whether from global warming or other causes.

The NRC report looks at aspects of climate change impacts:

Declines in many pollinator groups are associated with habitat loss, fragmentation, and deterioration … Changes in phenological synchrony and in distributions of pollinators and plants result from global climate change could lead to a decline in interactions between flowers and pollinators. Disruption of migratory routes is evident in hummingbirds, nectar-feeding bats, and some butterflies.

The report also looks at the effect on honeybees from pesticides used on crops and from mosquito control. Other causes include monoculture and other agricultural methods such as “loss of field margins” and replacing crop rotations involving legumes with fertilizer.

The deterioration in the ozone layer is a humongous problem — after all, life could not come onto land until there was sufficient stratospheric ozone to protect plants and animals from UV. But the solutions are relatively simple. The problems leading to pollinator decline are harder to find solutions to. See the NRC report for some suggestions.

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