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Desertification Indicator System for Mediterranean Europe


1. Definition

Name

PERIOD OF EXISTENCE OF LAND USE TYPE

Brief definition

The present land use type, and the period of existence of that land use type, is important as it is related to cumulative long effects on land protection or on land degradation.

Pine forested area in the island of Lesvos which remains under the same type of vegetation for more than three thousands of years as it is evidenced by existing historical documents, well protected from degradation and desertification (photo by C. Kosmas)

Unit of measure

Years

2. Position within the logical framework DPSIR

Type of Indicator

State

3. Target and political pertinence

Objective

Contribution to the definition of the desertification risk of a certain area.

Importance with respect to desertification

The extensive deforestation of hilly areas and intensive cultivation with rainfed crops such as cereals, almonds, vines, and olives in the Mediterranean has already led to soil erosion and degradation to various degrees in the last century. The stage of land degradation depends on the type and the period of existence of land use type. For example some hilly areas that were under forest with deep soils were brought into cultivation of cereals or olives. Under the prevailing management practices the erosion rates in areas with cereals are higher than in olive groves. Today several areas cultivated with cereals for decades or centuries have degraded appreciably and are now abandoned due to low land productivity. The loss in land productivity soon becomes apparent in areas with soils having limiting subsurface layers, such as petrocalcic horizons or bedrock. If high erosion rates occur over a long period the soil depth is drastically reduced and under hot and dry climatic conditions such areas are desertified. However, areas cultivated with olives under similar soil, topographic, and climatic conditions are better protected from degradation and desertification for longer periods than areas cultivated with cereals.

International Conventions and agreements

The UNCCD emphasizes that combating desertification must be tackled within the general framework of actions to promote sustainable development.

Secondary objectives of the indicator

Within the ESA model: a) investigation of the individual processes linked to land degradation and desertification, b) assessment of desertification risk.

4. Methodological description and basic definitions

Definitions and basic concepts

The importance of a certain type and period of land use becomes apparent in association with different annual erosion rates occurring under Mediterranean climatic conditions. Experimental data for different places within Mediterranean Europe, as measured under various land uses types, have shown significant differences in soil erosion rates. Typical Mediterranean land uses can be graded in order of decreasing effect on soil erosion as following: vines, eucalyptus, winter wheat, shrubland and olives. Specifically, for cereals in the rainfall range of 280 mm per year to 700 mm per year, sediment loss may fluctuate generally between 15 and 90 t km-2 per year. The erosion rates measured under eucalyptus plantations ranged from 1.4 t km-2 per year to 65.6 t km-2 per year. For olives grown under semi-natural conditions, i.e. with an understory vegetation of annual plants, a sediment loss greater than 5.3 t km-2 per year is uncommon. Greater erosion rates are expected from soils cultivated with vines and almond trees. The erosion rates under such crops can range between 67 t km-2 per year and 460 t km-2 per year.

Benchmarks Indication of the values/ranges of value

  • <5 years,
  • 5-10 years,
  • 10-20 years,
  • 30-50 years,
  • >50 years

Methods of measurement

By contacting the land user or by interpretation of a series of aerial photographs.

Limits of the indicator

No limits

Linkages with other indicators

Land use type, Vegetation cover, Rainfall, Soil depth, Tillage operations.

5. Evaluation of data needs and availability

Data required to calculate the indicator

Period of existence of a certain land use type.

Data sources

Necessary data are easily available and accessible and the cost/benefit ratio is reasonable.

Availability of data from national and international sources

Data can be obtained from various regional, national or international institutions involved in collecting and elaborating such data.

6. Institutions that have participated in developing the indicator

Main institutions responsible

Agricultural University of Athens, Greece

Other contributing organizations

Universities of Lisbon, Murcia, Basilicata, Amsterdam, Leeds

7. Additional information

Bibliography

Geeson, N., Brandt, J., and Thornes, J., 2001. Mediterranean Desertification: A mosaic of processes and responses. J. Wiley & Sons, London, 439 p.

Other references

Kosmas, C., Danalatos, N., Cammeraat, L.H., Chabart, M., Diamantopoulos, J., Farand, R., Gutierrez, L., Jacob, A., Marques, H., Martinez-Fernandez, J., Mizara, A., Moustakas, N., Nicolau, J.M. Oliveros, C., Pinna, G., Puddu, R., Puigdefabregas, J., Roxo, M., Simao, A., Stamou, G., Tomasi, N., Usai, D., and Vacca, A., 1997. The effect of land use on runoff and soil erosion rates under Mediterranean conditions. Catena, 29:45-59.

Contacts Name and address

Agricultural University of Athens
Dr Constantinos Kosmas
email: lsos2kok@aua.gr