Good husbandry is about managing
all populations in order to optimize the ecology and the sustainable output of
that ecology. A lot of environmentalists
find it difficult to accept that man has a serious role in this process.
The most pressing reality out
there is that deer herds in particular need to be tightly managed, often in
conjunction with some predator activity.
The problem with wolves of course is that they will hunt us. Thus they must be constrained to
refugia. The solution is to make the
herds property and allow individuals to take on the task.
We have the technology to
accomplish this fairly easily today.
Otherwise we need to actively manage
the wild places anyway and using them as occasional refugia for specific predators
useful to maintaining an advantageous balance is appropriate. It is the linkage between wolf induced
ruminant behavior and beaver populations that is a big surprise. Usually it is not that subtle and it explains
the poor recovery of beaver in the western US.
Most linkages are not like that
fortunately but we must have our eye on them and also understand that a given
choice is neither good nor bad but predisposes an outcome that may or may not
be advantageous. It is advantageous to
not have a wolf beaver ecology next door to human activity. We need a different ecology and must mange
accordingly.
Loss of large predators disrupting multiple plant, animal and human
ecosystems
by Staff Writers
Without wolves, the growth of young aspen trees and willow almost
ground to a halt, and there were fewer beaver. Plant communities,
tree growth and stream ecology all were affected. With the return of wolves,
those areas are now returning to health, and in places, aspen and willow are
recovering where they had been declining
The enormous decline of large, apex predators and "consumers"
ranging from wolves to lions, sharks and sea otters may represent the most
powerful impacts humans have ever had on Earth'secosystems,
a group of 24 researchers concluded in a new report in the journal Science.
The decline of such species around the world is much greater than
previously understood and now affects many other ecological processes through
what scientists call "trophic cascades," in which the loss of
"top down" predation severely disrupts many other plant and animal
species.
Such disruption is sufficiently severe that it now affects everything
from habitat loss to
pollution, carbon sequestration, wildfire, climate, invasive species and spread
of disease, the scientists said. It is also a driving force in the sixth mass
extinction in Earth history, which the researchers said is now under way.
"We now have overwhelming evidence that large predators are hugely
important in the function of nature, from the deepest oceans to the highest
mountains, the tropics to the Arctic," said William Ripple, a professor of
forestry at Oregon State University, co-author of the report and an
international leader in this field of study as director of OSU's Trophic
Cascades Program.
"In a broad view, the collapse of these ecosystems has reached a
point where this doesn't just affect wolves or aspen trees, deforestation or
soil or water," Ripple said. "These predators and processes
ultimately protect humans. This isn't just about them, it's about us."
Historically there has been little appreciation of how large predators
affected so many other species, the researchers said, and too often such
processes were studied one plant or animal at a time in a small area, failing
to appreciate the larger disruption under way.
Based on the new understanding that is emerging, the scientists argued
that the burden of proof should now be shifted, to assume that top predators
have major effects on ecosystems until proven otherwise.
"We propose that many of the ecological surprises that have
confronted society over past centuries - pandemics, population collapses of
species we value and eruptions of those we do not, major shifts in ecosystem
states, and losses of diverse ecosystem services were
caused or facilitated by altered top-down forcing regimes," the scientists
wrote.
Pioneering research done in recent years at OSU and cited in this
study, for instance, has outlined the effect that the loss of wolves had in Yellowstone National Park
Without wolves, the growth of young aspen trees and willow almost
ground to a halt, and there were fewer beaver. Plant communities, tree growth
and stream ecology all were affected. With the return of wolves, those areas
are now returning to health, and in places, aspen and willow are recovering
where they had been declining.
The scientists cited many examples in their study, both terrestrial and
marine:
+ Reduction of cougar in Utah
+ Industrial whaling in the 20th century likely caused a killer whale
diet shift and a dramatic decline of sea lions, seals and sea otters.
+ Decimation of sharks resulted in an outbreak of cow-nosed rays and
the collapse of bay scallop fisheries.
+ Sea otters enhance kelp abundance by limiting herbivorous sea urchins.
+ The reduction of lions and leopards in Africa
led to a population explosion in olive baboons, which bring intestinal parasites
to humans who live in close proximity to them.
For too long, the researchers said, large animals have been seen as
"riding atop the trophic pyramid" but not really affecting the
species and structure below them. That's a fundamental misunderstanding of
ecology, they said.
This report was done by scientists from 22 different institutions in
six countries. Studies were supported by the Institute for Ocean ConservationScience at
Stony Brook
University , National Science
Foundation, Natural Sciences and Engineering Research Council of Canada
"Top-down forcing must be included in conceptual overviews if
there is to be any real hope for understanding and managing the workings of
nature," they wrote in their conclusion.
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