Transcript Landscape Ecology: Conclusions and Future Directions

Landscape Ecology:
Conclusions and Future
Directions
What have we learned?

1. The complex patterns observed on
today’s landscape result from many causes,
including variability in the abiotic
template, biotic interactions, natural
disturbances, and both past and present
patterns of human settlement and land use.
What have we learned?

2. There is no right scale for landscape
ecological studies, but scale effects must be
considered carefully; concepts such as
equilibrium and species persistence are
scale dependent.
Disturbance
Regime
Environmental
Constraint
Forest
Process
Vegetation
Pattern
Urban et al. 1987
What have we learned?

3. Many metrics are available for
quantifying landscape patterns; one metric
is insufficient for characterizing a
landscape, yet there is no standard recipe
for determining how many and which ones
should be used.
What have we learned?

4. Organisms are influenced by spatial
pattern, but pattern-process interactions
involving organisms are scale dependent
and require an organism-based view.
What have we learned?

5. Disturbances both create and respond to
landscape heterogeneity, and thus landscapes may
be strongly influenced by shifts in disturbance
regimes.


Fire both creates and responds to patterns of fuel
availability.
Fire suppression on the east side of the Cascades has
profoundly alter fuel loads. This has lead to fires of
unprecedented severity.
What have we learned?

6. Because pattern matters, natural
disturbance can be very important for
biodiversity and for ecosystem function.

The characteristics of a disturbance regime
(frequency, severity and size) selects for a
particular suite of life history attributes. This
suite of life history attributes in turn
influences ecosystem function.
What have we learned?

7. Populations or guilds can produce
important feedbacks to ecosystem
processes and landscape patterns.
What have we learned?

8. Ecosystem function in terrestrial and
aquatic ecosystems can be influenced by
landscape position.
Swanson et al. 1988
What have we learned?

9. Elements of the landscape may serve as
sources or sinks for nutrients that move
across the terrestrial landscape or from the
land to aquatic ecosystems.

Patches of red alder along streams serve as a
nitrogen source
What have we learned?

10. Human influences (e.g., land-use
change) may be dominant factors
controlling ecological dynamics at broad
scales.
Research Directions

1. Spatial heterogeneity and ecosystem
processes.
Research Directions

2. Relating landscape metrics to ecological
processes.
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Statistical properties and behavior of metrics need to
be better understood. Some metrics yield similar
values for very different patterns.
The relative sensitivity of different metrics to
detecting changes in the landscape is not known
The empirical relationships between landscape
patterns and ecological processes of interest must be
better documented and the underlying mechanisms
understood.
What should we measure and why and when is a
change in a metric ecologically significant?
Research Directions

3. Thresholds, nonlinearities and rules for
scaling.
Research Directions

4. Feedbacks between organisms and
ecosystems in space.
Research Directions

5. Causes and consequences of land-use
change
Research Directions

6. Sampling over large areas. How do we
do it in a way that permits inferences about
the effect of heterogeneity? This may
require the development of new statistical
tools.