2005
22 November 2005. In
Give and Take of Evolution, a Surprising
Contribution From Islands. By CARL
ZIMMER. NY Times. Excerpt:
Islands hold a special place in the
hearts of evolutionary biologists. When
Charles Darwin visited the Galápagos
Islands in 1835, he was stunned by the
diversity of birds, which helped guide
him to his theory of evolution by natural
selection. Beginning in the middle of
the last century, the ornithologist
Ernst Mayr laid the foundation for the
modern understanding of the way new
species evolve, arguing that they mainly
emerged when populations became geographically
isolated. Mayr based his theory on his
studies of birds from Pacific islands.
Yet islands have generally been considered
evolutionary dead ends. After animals
and plants emigrated from the mainland,
it was believed that they became so
specialized for island life that they
could not leave. They eventually became
extinct, only to be replaced by new
arrivals from the mainland....But Dr.
Filardi and Robert Moyle, a colleague
at the museum, have found evidence that
islands can act as engines of evolution
instead of dead ends. Animals can spread
from island to island, giving rise to
an explosion of new species, and even
colonizing the mainland again. The results
suggest that conserving biodiversity
on islands is vital for the evolution
of new species in the future.
Dr. Filardi made this discovery by studying a group of Pacific
island birds, known as monarch flycatchers, ...In one lineage,
the monarch flycatchers tripled their body size in less than
a million years. "This stuff can happen really fast," Dr.
Filardi said. This evolutionary wave returned to its origins
when flycatchers from the Solomon Islands colonized Australia
and New Guinea.
24 May 2005. New
Rule on Endangered Species in the Southwest.
By FELICITY BARRINGER. NY Times. Excerpt:
WASHINGTON, May 23 - The southwestern regional
director of the United States Fish and Wildlife
Service has instructed members of his staff
to limit their use of the latest scientific
studies on the genetics of endangered plants
and animals when deciding how best to preserve
and recover them. At issue is what happens
once a fish, animal, plant or bird is included
on the federal endangered species list as
being in danger of extinction and needing
protection. Dale Hall, the director of the
southwestern region, in a memorandum dated
Jan. 27, said that all decisions about how
to return a species to robust viability
must use only the genetic science in place
at the time it was put on the endangered
species list - in some cases the 1970's
or earlier - even if there have been scientific
advances in understanding the genetic makeup
of a species and its subgroups in the ensuing
years. His instructions can spare states
in his region the expense of extensive recovery
efforts. Arizona officials responsible for
the recovery of Apache trout, for example,
argue that the money - $2 million to $3
million in the past five years - spent on
ensuring the survival of each genetic subgroup
of the trout was misdirected, since the
species as a whole was on its way to recovery.
...Six weeks later, his counterpart at the
mountain-prairie regional office, in Denver,
sent a sharp rebuttal to Mr. Hall. "Knowing
if populations are genetically isolated
or where gene flow is restricted can assist
us in identifying recovery units that will
ensure that a species will persist over
time," the regional director, Ralph
O. Morgenweck, wrote. "It can also
ensure that unique adaptations that may
be essential for future survival continue
to be maintained in the species." Mr.
Hall's policy, he wrote, "could run
counter to the purpose of the Endangered
Species Act" and "may contradict
our direction to use the best available
science in endangered species decisions
in some cases." ...That would make
it easier for officials to approve actions
- like construction, logging or commercial
fishing - that could reduce a species's
number. ...Bruce Taubert, the assistant
director for wildlife management at the
Arizona Game and Fish Department, said of
the new policy, "We support it," adding,
in the case of the endangered Apache trout, "Why
should we spend an incredible amount of
time and money to do something with that
species if it doesn't add to the viability
and longevity of the species that was listed?
By not having to worry about small genetic
pools, we can do these things faster and
better," Mr. Taubert said. But Philip
Hedrick, a professor of population genetics
at Arizona State University, said that it
made no sense to ignore scientific advances
in his field.
"Genetics and evolutionary thinking have
to be incorporated if we're going to talk
about long-term sustainability of these species," he
said.
"Maybe in the short term you can have
a few animals closely related and inbred out
there, but for them to survive in any long-term
sense you have to think about this long-term
picture that conservation biologists have
come up with over the last 25 years."
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