Land use changes, land degradation and desertification

 1.- Identification and quantification of land-use and land-cover changes, investigation of their causes and development of mitigation strategies.
1.1. Establishment of a homogenized baseline data set of the status of land-use at a specific time (e.g. around 1980); identification and quantification of the changes that occurred since then. Quantification of their importance at various scales.
1.2. Assessment of relative role of the driving forces of the observed changes such as socio-economic, demographic and political drivers (in cooperation with the socio-economic research community) versus the climatological impacts.
1.3. Analysis of the importance of land surface processes for land degradation and desertification and development of restoration strategies.

 For most of the indicated research needs, data and investigation results are readily available but they need considerable homogenization efforts. Where gasps in our understanding may become evident the following research approaches are considered for advanced insights into the system:
- Direct observations and measurements of the dynamics in land use changes and land degradation. This includes monitoring and description of the patterns of change, and improving measuring methodologies. Among the main topics of interest, to improve understanding on the role of plant communities in making more efficient use of water resources and in soil stabilization, the physiological features of its individual components.
- Development of empirical diagnostic models of the changes in land cover characteristics, aiming at interpreting from patterns to processes, the effects of land use changes on vegetation and ecosystem dynamics, e.g. new agriculture technologies,..

 2.- Relationships between land use and land cover changes and the physical climatic-hydrological system components.
2.1. Land use and land cover changes and atmospheric processes. Atmospheric processes are influenced by albedo surface roughness and surface temperatures, that regulate the exchange of momentum, radiation, heat, water, aerosols and gases.
To assess the impact of land-surface changes on atmospheric circulation system mesoscale models should be used to explore the response of atmospheric dynamics to changes in the boundary conditions.
With respect to atmospheric composition the major issue in the Mediterranean area is the eolian erosion and industrial emissions that rise aerosols and dust. The impact of these agents can only be assessed by an inter-comparison of radiative transfer calculations with measurements of the radiative properties of the atmosphere, e.g. Anchor Stations. The investigation of these impacts should become a joint effort with the climate and atmospheric research communities.
2.2. Land use and land cover changes and water availability. An overriding issue for land surface sustainable development in the Mediterranean area is the availability of water. It is not only a question of providing water to the competing users but affects also the structure of the soil and, e.g. its ability to resist eolic erosion, though with too much precipitation the danger of water erosion increases.
It is therefore a priority research item to assess jointly with the "water" community variability and trends of precipitation with respect to totals, intensities, periodicities, duration of dry spells and their geographical synergetics (eastern Mediterranean versus western Mediterranean; versus south).
A second important item is the assessment of soil moisture and the availability of water in the aquifers that are exploited to satisfy the users. Satellite techniques must be developed further to contribute to the large scale assessment of the surface soil moisture that is to be coupled by models with the lower levels.

 Monitoring Needs
As a preliminary approach to the analysis of land use driving forces, there is a need of developing socio-economic datasets using the available information from the different states/institutions and producing new ones.
In the monitoring and surveillance of land use changes two issues emerged as of high priority: the periodical updating of the distribution of functional land use/land cover types, and the measurement of soil moisture and soil depth.
A long term (also retrospective) monitoring project based on remote sensing at different spatial resolution should be launched to apply presently developed techniques to the whole Mediterranean Region.
A network of ground water level measurements should be established to provide an estimate of the extraction-recharge ratio in critical areas.
Anchor Stations will play a major role to validate the applied techniques and to monitor land-surfaces processes, water availability, and atmospheric radiation parameters such as optical depth.. Such Anchor Stations might be established in sensitive areas ("hot spots"). Time series of satellite observations might be helpful to identify these critical areas.

 Training & Capacity Building Needs
Can be achieved by cooperative research work. Project integrating the North Africa Mediterranean sub-region to global and long-term Mediterranean investigations should be promoted, including field work, laboratory analysis, and

remote sensing. These projects would facilitate methodologies harmonization and intercalibration. Here the "anchor stations" can play an important role as focal points for these studies. Target areas should be defined under the perspective of the Developing Countries requirements. To stimulate contacts between scientists from both sides of the Mediterranean, 'summer schools' and/or workshops should be arranged with participants of both areas and taking advantage of the existing networks or institutions (e.g. CIHEAM)