Fjölrit RALA - 05.12.1999, Side 150

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CONCLUSIONS OF THE WORKSHOP
derstanding of ecosystem function (plant, soil, and animal), and the role extemal
driving forces have in dictating ecosystem behaviour.
• Some ecosystem processes are event-driven and the ecosystem response to ex-
treme events can be more important that the mean conditions in determining the
long-term trend. Their response to stress is commonly non-linear due to positive
feedback loops. There may exist ecological thresholds, beyond which degradation
may accelerate and become irreversible. These thresholds have not been clearly
identified, however.
• There was a general consensus that the desertification concept needs to be re-
evaluated as knowledge about the processes and mechanisms increases worldwide.
Functional analysis of rangeland ecosystems has developed to the point that we
can move from the mere description of superficial phenomena to a working under-
standing of rangeland fiinction. This understanding can be distilled into function-
ally relevant indicators. There are still important gaps in our understanding of
rangeland function, however.
• Indicators functionally relevant at one scale can lose their meaning when up-scaled
to larger areas. When rangeland systems are analysed at the landscape level, indi-
vidual patches are found to be spatially interconnected with significant fluxes of
matter from one landscape unit to the next. Processes need to be studied at the
spatial and temporal scales management decisions are made at.
• Rangelands are degraded when the functional integrity of the system is damaged
and thus leading to reduced productive capacity and loss of resiliency. Rangeland
degradation represents a continuum of system states with desertification as the end
point. Productive capacity of rangelands will fluctuate due to extemal driving
forces. These fluctuations need to be separated from long-term trends.
• The best management of rangelands can only be devised in the context of the man-
agement' objectives of the stakeholders. The needs of the stakeholders, however,
can only be met within the limits posed by the supply capacity of the soil-plant
system.
• Current level of understanding of rangeland function has been gained from long-
term studies, using broad based ecological approach (including the soil system).
These studies need to be continued.
• There is a need for issue-driven research programs, combining several scientific
disciplines aimed at frnding solutions for desertification control.
Implications for the Convention to Combat Desertification
• The workshop participants welcomed strengthened co-operation among climati-
cally different regions under the CCD Convention. They also agreed that the evo-
lution of the Convention could be enhanced through broad-based scientific input.
The interaction across the science-policy interface needs to be enhanced.
• The scientific community needs to recognise the importance of the development of
indicators (impact indicators and implementation indicators) and benchmarks for
these indicators under the CCD Committee on Science and Technology.