Hornbills Seen as Rain Forests Savior
8/17/98
*******************************
RELAYED TEXT STARTS HERE:
Title: Hornbills Seen as Rain Forests Savior
Source: The San Francisco Examiner
Status: Copyrighted, contact source to reprint
Date: 8/17/98
Byline: Larry D. Hatfield
Bay Area scientists show hornbills maintain biodiversity by dispersing seeds
over a wide
area
It has a raucous call, massive bill and huge wingspan and until recently it was
thought
to be a sedentary stay-at-home creature, but scientists now say the hornbill may
be the
key to saving the vanishing tropical rain forests in western and central Africa.
Ironically, saving the rain forests also may determine whether the magnificent
fruit-
loving bird itself survives the depredations of man.
Biologists at San Francisco State University and UC-Davis have discovered that
the
toucan- like birds play an elemental role in reseeding the rain forests.
A three-year study in a remote Cameroon rain forest showed that the hornbill
flies 100
miles or more when foraging for ripening fruit, in the process dispersing seeds
- through
its droppings -- for nearly a quarter of the 59 species of trees in the forest.
Until the SFSU-UCD study, it was thought the hornbill was sedentary, confining
its
activities to small patches of forest and playing a relatively unimportant role
in
reseeding.
As other important seed dispersers such as elephants and primates continue to
fall prey
to hunters and habitat destruction, hornbills become even more important for
rain forest
regrowth and survival, the university team said.
The Cameroon study found that nearly all the seeds dispersed by the wandering
hornbills
germinate successfully, making them one of the prime agents of lowland rain
forest
regeneration.
"The survival of the rain forest appears to rely to a large degree on the
hornbills'
ability to disperse seeds of so many species," said SFSU biology Associate
Professor
Thomas Smith, a co-author of two scientific papers on the Cameroon study.
"If we have any hope of protecting rain forests we need to protect not just the
pattern
of biodiversity but also the processes that create it," Smith said. "Our work
suggests
that by dispersing seeds, these magnificent birds are vital agents of
biodiversity."
The biologists said that to save the rain forest it is necessary to save the
hornbill,
and vice versa.
"The birds' surprisingly large range suggests that their own survival depends on
preserving large expanses of rain forest intact," said Smith, who also holds an
associate
professorship at the Center for Population Biology at Davis.
The study, reported in the current issues of the Journal of Tropical Ecology and
Animal
Conservation, found that two hornbill species -- Ceratogymna atrata and C.
cylindricus
-- actively soar across gaps in the forest in search of ripe fruit. A third
species -- C.
fistulator - is sedentary.
"Monkeys and elephants aren't as good at moving across gaps in the forest," said
Smith,
"so hornbills likely provide a crucial first step in forest regeneration,
particularly in
regions that have been cleared."
The study was the first to document the hornbills' surprisingly large range and
the
extraordinarily high numbers of plants for which they disperse seeds.
"Hornbills were thought to live in relatively confined rain forest habitats,"
said Ken
Whitney, a doctoral candidate at Davis who led the seed-dispersal studies as an
S.F.
State graduate student. "But this research shows that the movement pattern of a
few
hornbill species may be more like that of elephants and some primates, rather
than forest
birds."
Whitney was the senior author of the scientific papers in the two publications.
Surmising that the resourceful hornbills may actually be nomads rather than
migrants,
Smith and his colleagues are working with scientists at the Wildlife
Conservation Society
and NASA's Jet Propulsion Laboratory to track the birds' movements by satellite.
They
will attach small radio transmitters to as many as 30 of the big birds, and NASA
will
track their wanderings. The study was funded by the New York Zoological Society/
Wildlife Conservation Society, the National Science Foundation, S.F. State and
ECOFAC
Cameroon. Other team members included S.F. State graduate students Mark Fogiel,
Aaron
Lamperti, Kimberly Holbrook, Donald Stauffer and Britta Hardesty, and SFSU
biology
Professor V. Thomas Parker.
c1998 San Francisco Examiner