Thursday, November 10, 2011

November 10, 2011

The pollinator crisis: What's best for bees

Pollinating insects are in crisis. Understanding bees' relationships with introduced species could help.

By Sharon Levy

Bees thrum among bright red blossoms on a spring day on Mount Diablo, near San Francisco Bay. Alexandra Harmon-Threatt, a young ecologist just finishing her doctorate at the University of California, Berkeley, lovingly identifies an array of native pollinators. She points out three species of bumblebee, each with a unique pattern of black and yellow stripes. There are bee-flies, members of the fly family covered in soft brown fur, which look and act like bees. Among the native insects are plenty of honeybees (Apis mellifera), the species raised by beekeepers worldwide and introduced to the Americas by English settlers in the seventeenth century. All these insects are drawn to a clump of red vetch (Vicia villosa), an invasive weed. Just down the road is a patch of native lupins, laden with purple blossoms. But the lupins bloom in silence: no bees attend them.

For the past three years, Harmon-Threatt has been studying the ways in which the native yellow-faced bumblebee (Bombus vosnesenskii) uses the plants growing in the area. By capturing bees as they visit plants and then sampling the pollen they carry, she has confirmed in unpublished work that they get much of their food from introduced plants. And by analysing the amino-acid content of pollen, Harmon-Threatt has shown that bee foraging behaviour can be driven by a craving for nutrients rather than an evolved attachment to a specific plant. Although many conservationists assume that introduced plants are always destructive, her work shows that it's not necessarily so from a bee's point of view. What matters to most bee species is the abundance and quality of pollen — and if an introduced plant, such as the red vetch, offers more protein-rich food than the natives around it, the bees will collect its pollen.

Harmon-Threatt is one of a growing group of scientists studying the evolving relationships between native bees and introduced plants. Their work is critical in a world where human actions have dramatically shifted the distributions of plants and are forcing a pollinator crisis...

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Officials demonstrate 'Marsh Master,' whack fire-prone phragmites on Staten Island

STATEN ISLAND, N.Y. -- What’s taxicab yellow, weighs 6,000 pounds but can stay afloat in water by virtue of pontoon-like treads and boasts an 8-foot blade?

Apparently the answer to prayers of Oakwood Beach residents and other Staten Islanders, whose homes and property abut fire-prone phragmites that threaten their safety.

Called a Marsh Master, the noisy hunk of aluminum cut a wide swath through 9-foot-high phragmites on dead-end Kissam Avenue today, site of a 2009 Easter Sunday fire that ravaged homes.

The Marsh Master — which Dmytryszyn likened to a "modified lawnmower" — is on loan for two days from the Walkill National Wildlife Refuge in Sussex, N.J., in a city, state and federal government arrangement brokered by Borough Hall for demonstration purposes.

Dmystyszyn said Borough Hall will seek a federal grant in the range of $50,000 to enter into a contract with the National Parks Service to cut down phragmites every three months for the next two to three years in a pilot project, beginning this spring...

Read the full story at link.


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