What purposes do reserves serve?
Biodiversity
Many ecologists believe that the most efficient way to
maintain biological diversity is by designating a well-designed
system of reserves that encompass an array of ecosystem
types and conditions (e.g., Noss et al. 1995). Thus, efforts
to conserve biodiversity are often linked to identification and
protection of forest reserves. Ecologists agree that a comprehensive
system of such lands can probably protect populations
of most species, along with much of their genetic
diversity and the natural communities in which they occur.
A fundamental question related to current policy debates
over the future of reserves, however, is whether biodiversity
could be maintained as well as or better in forests that are
managed with the primary goal of timber production. This will
be considered in more detail in a following section. It is sufficient
to note here that by carefully logging a forestpaying close
attention to vegetation structure, coarse woody debris, harvest
unit patch size and context, and other ecological considerations
discussed earlier in this reportit is likely that one could maintain
many of the species found in forest reserves.
Providing habitat for any one species of concern to conservationists
may well be compatible with harvesting timber.
For example, in many southern forests, careful timber
management can provide habitat for the endangered redcockaded
woodpecker. Similarly, in the coniferous forests of
the Pacific Northwest, sophisticated silvicultural manipulations
of managed forest stands under lengthened cutting
rotations can, at least hypothetically, provide for northern
spotted owls, flying squirrels, and related species (Carey et
al. 1996). However, these approaches work because the focus
is on one or a relatively few species. Since most forest
ecosystems include thousands of species, it is likely that some
species would lack adequate or suitable habitat in an intensively
managed forest. Explicitly trying to incorporate the
requirements of thousands of species into a timber management
plan is clearly impossible.
Any reduction of diversity that might occur if all current
reserves were returned to intensive management would
raise the presently unanswerable question of how much biodiversity is sufficient to maintain resistance to pests and
sustain the capacity of the forest ecosystem to adapt to
changing conditions. The extent and functions of biodiversity,
especially genetic diversity, at the landscape level are poorly
understood at present. Therefore, one very important reason
for biologists emphasis on reserves is the high level of
uncertainty associated with providing for adequate
biodiversity in managed landscapes. In the Pacific Northwest,
biologists were essentially unanimous in choosing the
certainty of providing suitable habitat for late-successional,
old-growth species in a system of forest reserves over much
greater uncertainty associated with growing such habitat
as a part of timber management programs (Forest Ecosystem
Management Assessment Team 1993, Johnson et al. 1999).
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