Manual for describing land degradation indicators

Table of Contents

1. Editor
2. Introduction
3. Classification of indicators
4. Land degradation indicators
5. Evaluation and short-list of indicators
6. Explanations for filling the information sheets
   1. General information
   2. Climate indicators
   3. Water indicators
   4. Soil indicators
   5. Vegetation indicators
   6. Water runoff indicators
   7. Forest fires indicators
   8. Agricultural indicators
   9. Cultivation indicators
   10. Husbandry indicators
   11. Land management indicators
   12. Land use indicators
   13. Water use indicators
   14. Tourism indicators
   15. Social indicators
   16. Institutional indicators
7. Farm survey research
8. Focus group approach
9. References

Land use indicators

Land abandonment: It is related to a decreasing land productivity usually resulting in change land use from agriculture to grazing land. The extensive deforestation and intensive cultivation of hilly areas especially during the last decades has led to soil erosion and the formation of shallow skeletal soils. As the soil is eroded, land use is usually shifted from agriculture to pasture due to increasingly poor yields from the various agricultural crops. Such a pasture land in the Mediterranean region is defined as an abandoned land today. Various authors have simultaneously used the terms 'abandoned land' and 'grazing land', but grazing or hunting an abandoned land is considered a traditional use in the Mediterranean region. Land abandonment does not necessarily mean that land is no longer used, either by agriculture or any other rural economical activity. It means a change in land use from the traditional or recent pattern to another, less intensive pattern. Data on land abandonment can be obtained from statistical service or consultation with the local cooperatives. The analysis of ortho-photomaps or satellite data can be used. The rate of land abandonment is expressed in hectares of land abandoned every 10 years on 10 km² territory. The following four classes of rate of land abandonment have been defined: (a) low, (area <10 ha); (b) moderate (area 10 -25 ha); (c) high (26 - 50 ha); and (d) very high (>50 ha).

Land use intensity: It is related to the degree in which the cultivation of the land is mechanized, the application or not of fertilizers and pesticides. Land use intensity is related to the processes of land degradation and desertification such as soil erosion, soil structure decline, and Salinization. Three classes of land use intensity are distinguished to: (a) low, (b) medium, and (c) high. The definition of each class is based on the type of land use. 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.) .

The land use intensity 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.

The land use intensity for 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 actual number of animals grazing the land (ASR) and forming the ratio actual/sustainable. The following classes are distinguished: low (ASR<SSR), moderate (ASR = SSR to 1.5*SSR), and high (ASR>1.5*SSR).

The assessment of land use intensity for natural land (forests) requires a major distinction 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 (S) and the actual (A) yield of the forest and forming the ratio actual/sustainable. The following classes are distinguished: (a) low (A/S = 0), (b) moderate (A/S <1), and (c) high (A/S = 1 or greater).

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 site, the intensity of land use can be assessed as following: 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.

The assessment of land use intensity in recreation areas requires the basic distinction between passive and 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 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.

Period of existing land use: 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. 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 an order of decreasing effect on soil erosion as following: vines, eucalyptus, winter wheat, shrubland and olives under no-tillage conditions. The following 5 classes of period of land use have been defined: (a) <5 years, (b) 5-10 years, (c) 10-20 years, (d) 30-50 years, and (e) >50 years. The period of existing land use can be defined by contacting the land user or interpreting a series of aerial photographs.

Urban area: It is defined as the expansion of urban settlements into semi-natural and agricultural areas, often along the coast. Uncontrolled expansion is one of the major causes of loss of environmental resources in the Mediterranean basin. It is expressed in % or ha of soil sealed by built-up structures within agricultural and/or semi-natural land cover units over the studied territory. It can be easily defined by using ortho-photomaps or remote sensing image analysis.

Rate of change of urban area: Change of urban areas is expressed as the area covered over certain time. Its approach is to compare and combine mapping methods based on field surveys and remote sensing image analysis for an efficient geo-referenced identification and quantification of the extent of dispersed built-up structures within semi-natural/agricultural areas expressed in ha/10 years/10 km². The following 4 classes of change of urban areas have been defined: (a) very low (<5 ha), (b) low (5-10 ha), (c) moderate (10-20 ha), and (d) high (>20 ha).

Distance from the sea shore: This indicator is mainly used to assess the effect of water quality on soil Salinization risk. The shorter the distance of a site from the nearby seashore, the greater the risk of soil Salinization. In practice the shortest distance from the sea shore of a stuffy site can be measured with the aid of the most detailed material available such as topographic maps, aerial photos and satellite images. The following classes can be distinguished: <0.25 km, 0.25-1 km, 1-2 km, 2.-5 km, 5-8 km, 8-15 km and >15 km.