While it is gratifying to see some coverage of the
potential problems our current wildlife preservation systems face
in the presence of climate change, there are some continuing blind
spots that should be pointed out (HCN,
2/04/08).
First, as was noted in a 2002
HCN interview with conservation biologist
Michael Soule, the “pristine ecosystem” that the 1962 Leopold
report set as a target goal for the National Park Service was in
fact something of a fantasy. The Park Service has never adjusted to
the recognition that the early 19th century landscapes were wildly
out of any equilibrium due to diseases decimating Native American
populations. These conditions could never be sustained.
Furthermore, the more stable patterns from about 1490 or so were
developed by extensive Indian management, most obviously in the use
of fire but also in other horticultural pursuits that now are
abandoned. Thus any landscape in human memory was gardened in some
fashion; without recognition of this history, the Park Service’s
management of its biota will remain unrealistic.
Second,
there is a hint of the idea that ecosystems are a unit that will
travel as climates change. This is untrue, and the evidence is in
the record of ecosystems during the last glacial maximum. For
instance, in southern Nevada, rat middens record the coexistence of
species that today live in very separate environments. Individual
species, not entire ecosystems, react to changes in the
environment, so unless you know what every species is sensitive to,
you cannot easily anticipate moving things around. Probably the
best we can do is to open up corridors for biota to move freely,
rather along the lines The Nature Conservancy appears to be
considering.
Third, the issue of exotics is overblown. It
should be easy to distinguish plants and animals exotic to the
Americas from biota native to the New World. The former should
continue to be discouraged, while the latter should be welcomed.
While there is real concern that fragmentation of modern habitats
and the pace of global climate change might impede natural
responses, North American ecosystems have responded to substantial
changes in the past through shifts in position and interaction; we
should strive to accommodate such shifts to the greatest degree
possible.
Interestingly, when I present this set of
perspectives and issues to an introductory historical geology class
and offer them choices on how they think lands should be managed,
they distinctly prefer that wildernesses be allowed to change
without human intervention, despite their recognition that the
resulting ecosystems will not necessarily resemble any that existed
in the past. The people charged with the actual task of managing
these lands need to define such a broad vision, in essence
revisiting the Leopold commission in the light of both new
scholarship and new challenges. Such a vision will ease
nuts-and-bolts decisions on the ground, much as the Leopold report
led to rapid changes in the Park Service’s management of resources.
Craig Jones
Boulder, Colorado
This article appeared in the print edition of the magazine with the headline A new land ethic.
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