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Landscape Ecology and Management Topics Seminars
A series of seminars were presented in the Forestry and Range
Sciences Lab in La Grande, October 3, November 14, and December
5, 1996.
If you would like to see the online version of this Seminar,
click here
to see the Winter 1996 edition of Natural Resource News. The
sessions are also on videotape through our Video
Lending Library.
Session One:
The first session was Broadscale Assessments of Land-Use
Effects on Fishes of the Interior Columbia River Basin
by Danny C. Lee and Bruce E. Rieman of the Intermountain Research
Station in Boise. They reported on their work on the aquatic
assessment for the Interior Columbia River Basin Ecosystem
Management Project. Information was gathered form existing
sources and by surveying 150 biologists for their classification
of streams where data did not exist. Data were gathered for
164 subbasins and then aggregated. The result was groupings
of watersheds with similar distributions of fish species.
Species richness and number of exotics versus native species
was also examined.
More detailed information was gathered for key salmonids
and their habitat that was then used to extrapolate to get
fish status on the entire area. Some species are faring better
than others, but the general picture is of fragmentation and
isolation of species because of agricultural development,
dams, water diversions, roads, stream channelization, and
disruptive land use practices. Exotic species are also a major
concern. Even without further habitat loss or degradation,
we may well see a continued decline in fish populations.
Forest resource concerns were combined with aquatic habitat
status and some similarities were found. Three types of watersheds
were described: those that are high quality and can act as
templates; those that are somewhat degraded but still contain
elements of functional systems; and those that are severely
fragmented by dams, habitat loss, or presense of exotic species.
Areas that are high quality for both aquatic and forest ecosystems
are candidates for conservation. Areas that are low quality
for both (generally areas with many roads) are not likely
to yield much result from restoration. All other areas in
between show promise for recovery. They suggest concentrating
restoration work both in space and time to allow for longer
periods of recovery without entry. We might begin first in
heavily roaded areas and then remove many roads when the work
is done.
Session Two:
The second presentation was Landscape Analysis in Ecosystem
Management: Modeling Process and Pattern by Steve Garman,
Terrestrial Ecologist at OSU. Garman described his work in
attempting to identify past disturbance factors and their
sequence from satellite maps and aerial photos. He created
patterns by using models that simulate spread of fire and
bark beetle infestations of different intensities under two
moisture regimes. The resulting patterns were then analyzed
using total mean basal area, and spatial metrics—"nearest
neighbor" and "total edge"—to see if the particular
disturbance and disturbance sequence causing the pattern could
be determined.
Garman found that there are some conditions in which pattern
metrics could identify the process but that the resolution
of the data used makes a big difference in success. The simulations
used were extreme simplifications of actual disturbances,
and this work is preliminary serving to identify possibilities
for further investigation.
Session Three:
The third seminar was presented by Andy Hansen of Montana
State University on Mechanisms that Drive Bird Species
Diversity in Yellowstone National Park. His work examined
how human population growth surrounding nature reserves are
affecting the ecology of those ecosystems. Often the same
features that make an area a "hot spot" for plant
and animal species and diversity also attract human communities.
Vertebrate ecologists typically look at plant cover type
and seral stage and structure to explain species richness.
Recently there have been studies that look at abiotic factors
such as climate and elevation. One study found that potential
evapotranspiration explained over 92 percent of the variation
in species richness. Variables such as energy availiblity
of a site, may explain much of species distribution. Hansen
found a strong correlation of bird species distribution with
elevation.
Mapping human disturbance/use and natural disturbance was
also informative. The natural disturbance caused by fire resulted
in much more heterogeneity across the landscape than did logging
practices that were used. Hansen pointed out that the percentage
of forest in mature and old-growth historically ranged from
15 percent to 95 percent in the Yellowstone system. Thus the
concept of staying within the natural range of variability
has little meaning as a management objective.
Hansen further showed that even in unaltered cottonwood habitats,
the bird reproductive success was affected by uses in the
surrounding areas: cowbirds from agricultural areas killed
many young of other birds that nested in cottonwood in unaltered
riparian areas.
Hansen concluded that it is important to identify hot spots
and to understand what makes them "hot," such as
primary production potential and abiotic factors. Knowing
this can enable us to identify other potential hot spots where
the vegetation has been altered and can be restored.
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This research program is no longer active.
