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Activity 2.2
Landscape Processes
Background
Landscapes are defined as
spatial entities comprising of a set of interacting
ecosystems sharing a common broad abiotic environment
(climate, topography / land forms) and land use system.
Usually, their geographic range spans from a few to several
100 km2. In early approaches of global change, the essential
interactive nature of landscape scale processes was ignored,
and direct scaling was applied from local to regional and
global processes. However, the need to take into account
non-linear scaling, as well as the importance of
understanding and predicting global change effects on
landscapes in their own rights, have been gradually
recognized. In addition, both their scale and the broad
common characteristics (i.e., within landscape) make
landscapes amenable units for management and
planning.
Phenomena and processes that
are relevant to the landscape scale are:
- Disturbance -
disturbances that propagate across the landscape (e.g.
fire, herbivory, pests and pathogens) will be highly
sensitive to landscape pattern; all disturbances
contribute to the composition and dynamics of the
landscape;
- Flows of energy and
matter - not all flows are likely to be a simple weighted
sum over landscape patches (as is for example the case
for NPP); some flows are expected to strongly depend on
the actual spatial arrangement of patches, barriers, etc.
(e.g. water, and other elements flowing through the
soil);
- Dispersal and hence
species migration - movement of species through
landscapes is expected to depend both on their biology
and on landscape pattern, in particular habitat
fragmentation and dispersal corridors.
- Changes in land use and
their effects on ecological processes can be measured in
the landscape. Climatic and atmospheric changes are also
expected to have direct and indirect effects that might
be detectable at the landscape scale. In return,
landscape changes are expected to have potential feed
backs to atmospheric and possibly climatic processes. The
relative contribution of different global change drivers
and landscape scale processes are also likely to differ
between regions (e.g. Mediterranean vs. boreal
regions).
Objectives
The approach taken in this
Activity is to address the landscape issue from different
angles. The perspectives chosen are those considered as most
critical to the advancement of the general understanding and
prediction of the effects of global change on terrestrial
ecosystems, within the constraints of a three-year time
frame. The four research tasks address:
- Landscape scale
responses of vegetation to changing land use and
disturbance;
- Fire as a major
disturbance that will be influenced by climate, direct
effects of CO2 on vegetation, and land use, and will in
turn feed back to landscape pattern and
processes;
- The interactions between
species biology and landscape patterns that will
determine migration in response to climatic
change;
- The effects of landscape
pattern on primary ecosystem processes (in collaboration
with Task 4.2.1).
The outcome of this Activity
should be a series of models that can be used:
- to analyze interactions
between global change drivers and landscapes (theoretical
emphasis);
- as tools to compare
management scenarios (applied emphasis);
- as direct inputs or
general rules to be integrated into DGVMs.
Linkages
Tasks within Activity 2.2
will be highly interactive (Figure 1). In particular, Tasks
1 and 3 will be important suppliers of data and models for
the other Tasks
other IGBP
programs: BAHC, DIS, IGAC, LUCC, PAGES
Milestones
October 1997, San Diego,
Activity Workshop to develop operational plan
Sept. 1998 Creation of
Activity Web page
2000: Synthesis Workshop
(venue to be determined)
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