A piece of land, irrespective of its size, is characterized by a particular use. This use is associated with a given type of management which is dictated mainly by climate and changes because of environmental, social, economic, technological and political factors. Depending on the particular type of management or land use intensity, land resources are subject to a given degree of stress.

Cultivated area with cotton under high land use intensity subjected to frequently ploughing, fertilization, and irrigation (photo by C. Kosmas)

Exploitation of natural resources around the Mediterranean region has significantly changed in the last decades due to concentration of the population in certain areas, increase of tourists visiting the Mediterrranean region, expansion of the irrigated land, allocation of subsidies to certain types of agriculture and improvement of technology. The rural-urban migration has depleted the countryside of its inhabitants resulting in the gradual abandonment of agriculture and of traditional methods of cultivation. Thereafter, the abandoned land is managed by the remaining farmers intensively used without applying measures for land degradation protection. Moreover, the availability of heavy powerful machinery favored frequent and deep soil plowing at high speeds in directions usually perpendicular to the contour lines causing severe soil erosion problems. The large scale deforestation of hilly areas accompanied by intensive cultivation and overgrazing resulted in accelerated erosion and the formation of badlands with very shallow soils.

Subsidies allocated to the farmers have greatly contributed to the maintainance of particular types of land uses (e.g. olive groves), to reinforce the expansion of others (e.g. olive groves, durum wheat in hilly areas), to induce change of pastures to agricultural uses. The provision of subsidies to cattle raisers has contributed to the increase in the number of animals leading to overgrazing without a parallel effort to improve the grazing potential of pastures. Shepherds often damage the natural vegetation by deliberately setting fires to eradicate the vegetation and encourage the growth of new grass, which the livestock then overgraze. Overgrazing of climatically and topographically marginal areas, accompanying by fires, constitutes a desertification-promoting land use, further depleting the existing land resources.

Three classes of land use intensity are distinguished:

• low,
• medium, and
• high.

The definition of each class is based on the type of land use.

The assessement of the class of land use intensity is based on the land use type. For each of the following land use types, the intensity of the use is assessed separately.

• Agricultural land (cropland, pasture or rangeland)
• Natural areas (forests, shrubland, bare land)
• Mining land (quarries, mines, etc.)
• Recreation areas (parks, compact tourism development, tourist areas, etc.)

Agricultural land (cropland). The intensity of land use for cropland is assessed by characterizing the frequency of irrigation, degree of mechanization, the use of agrochemicals and fertilizers, the crop varieties used, etc. Three levels of land use intensity are distinguished for the agricultural areas as following:

• Low land use intensity (extensive agriculture). Local plant varieties are used, fertilizers and pesticides are not applied, yields depend primarily on the fertility of soils and environmental conditions. Mechanization is limited. In the case of seasonal crops, one crop is cultivated per year or the land remains fallow.
• Medium land use intensity. Improved varieties are used, insufficient fertilizers are applied and inadequate disease control is undertaken. Mechanization is restricted to the most important tasks such as sowing.
• High land use intensity (intensive agriculture). Improved varieties are used. Application of fertilisers and control of diseases are adequate. Cultivation is highly mechanized.

Pasture land. The quality of management of pasture land can be assessed by estimating the stock carrying capacity of the area and comparing it with the actual number of animals grazing the area. The sustainable stocking rate (SSR) expressed in animals per hectares can be calculated by from the following equation:

SSR = X * P * F / R

where: R is the required annual biomass intake per animal (sheep or goat 187.5 kg animal-1 year-1, FAO 1991), X is the fraction including grazing efficiency and correction for biomass not produced during the latest growing season (grazed: 0.5, non-grazed 0.25 year-1), P is the averaged palatable biomass after dry season (kg ha-1 ), F is the average fraction of the soil surface covered with annuals plant species. The intensity of use is determined by comparing the SSR and the number of animals grazing the land and forming the ratio actual/sustainable.

Natural land (forests). A major distinction must be made between natural forests and managed forest. In the case of natural forests the land use intensity is considered low as there is by definition absence of any management. In the case of managed forests, the intensity of use is determined by comparing the sustainable and the actual yield of the forest and forming the ratio actual/sustainable.

Mining land. Mining activities have a highly degrading effect both during their lifetime and after the end of the mining. Hence, a primary distinction is made between active and inactive mining sites. For active sites, the enforcement of reclamation policies is an important determinant of the degradation prospects of these sites. The intensity of land use can be assessed according to the following ideas for the case of active mining: Surface or subsurface mining with full erosion monitoring will be considered as well managed (low land use intensity). Surface or subsurface mining with moderate erosion monitoring will be rated with medium land use intensity. Surface or subsurface mining activities without, or with minimum erosion monitoring, will be rated with high land use intensity and high desertification risk.

Recreation areas. The diversity of types of recreation areas as well as the indirect effects of recreation activities on the environment requires the basic distinction between passive ad active recreation, since these may cause a significant different degree of stress on the land. Passive recreation, which is the least threatening to the environment, includes walking, nature seeing, mountain climbing, swimming and similar activities. Active recreation, which is more important for land degradation, includes skiing, cross country skiing games (e.g. sand rallies), etc. The quality of management is a function of both the size of the demand as well as the management strategies and practices employed. The assessment procedure would involve: (a) assessment of the visitor carrying capacity of the recreation area (maximum number of visitors permitted per year), (b) assessment of the actual number of visitors per year, (c) calculation of the ratio of actual to permitted number of visitors per year,(d) rating the quality of management as high if the ratio is equal or less than one, and as low if the ratio is greater than one.

Tourism development. Like recreation areas, tourist areas cannot easily assessed for the following reasons: (a) tourist areas may be part of or intermingle with urban areas or existing settlements in general, (b) in some cases tourism is the principal activity in an area, (c) tourism may affect not only the particular geographic area considered, but other locations due to environmental linkage, (d) tourism and recreation activities are difficult to distinguish in practice and may occur simultaneously at the same place, (e) tourism may be important in certain areas only such as coasts and sensitive ecosystems. The intensity of tourism development can be assessed following the procedure described for recreation.

Agricultural University of Athens,
Laboratory of Soils and Agricultural Chemistry,
Iera Odos 75,
Athens 11855, Greece

Dr. C. Kosmas
email: lsos2kok@aua.grlsos2kok@aua.gr