The Birds Are Falling: Avian losses could hit ecosystems hard
Ben Harder

If many bird populations dip toward extinction in the coming century, as
scientists predict, widespread harm could come to ecosystems that depend on
these birds to pollinate plants, disperse seeds, scavenge carrion, and
control insects.

Using a team of students to comb through the literature, Cagan H.
Sekercioglu, Gretchen Daily, and Paul Ehrlich of Stanford University filled
a database with information on diet, habitat, range, and other traits of all
the nearly 10,000 known living and extinct species of modern birds.

Consideration of the recognized threats to avian survival-including alien
predators, chemical contaminants, and fishing gear-led the scientists to
forecast that 500 to 1,300 species will vanish by the end of this century,
and that up to 1,050 others will become so depleted that they'll serve no
significant ecological function. In contrast, only 129 bird species are
known to have gone extinct in the past 500 years.

Scavengers, fish eaters, herbivores, fruit eaters, and nectar-drinking birds
are particularly vulnerable, the investigators suggest in the Dec. 21
Proceedings of the National Academy of Sciences.

Many roles that endangered birds play in their ecosystems will go unfilled,
the scientists predict. For instance, some birds that pollinate plants and
disperse fruit seeds are so specialized that their loss will jeopardize the
plants they serve, says Sekercioglu. Moreover, fish-eating seabirds
fertilize remote islands with their droppings.

The new study is unprecedented in its global scope and sobering in its
predictions, says ecologist Douglas J. Levey of the University of Florida in
Gainesville. "Their best-case scenario is alarmingly bad," says Levey.

Full Text at Science News
http://www.sciencenews.org/articles/20041218/fob5.asp

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