Exploring the Impact of Overgrazing on Soil Erosion and Land Degradation in a Dry Mediterranean Agro-Forest Landscape (Crete, Greece)

5sinoneThe impact of land management practices on soil erosion and land degradation was assessed during three consecutive years (December 2008–November 2011) in a rural area sensitive to desertification (Crete, Greece). The area is characterized by soils formed on flysch parent material, dry sub-humid climate with water deficit concentrated in summer, and frequent drought episodes. Precipitation, water runoff, sediment loss, soil moisture, air and soil temperature, and plant cover were recorded at two sites experiencing overgrazing and sustainable grazing. Sustainable grazing was associated with lower water runoff, reduced sediment loss and lower soil temperature than overgrazing. Plant cover protected soils from water erosion more effectively in the “sustainable grazing” plot than in the “overgrazing” plot. The study identifies overgrazing as a driver of land degradation in southern Europe and points out the contribution of sustainable management of pastoral landscapes in the mitigation of desertification risk.noneKairis O.; Karavitis C.; Salvati L.; Kounalaki A.; Kosmas K.Kairis, O.; Karavitis, C.; Salvati, L.; Kounalaki, A.; Kosmas, K

Land-use and land degradation processes affecting soil resources: Evidence from a traditional Mediterranean cropland (Greece)

Land degradation is a complex process resulting from the permanent interaction between physical and human factors. The effect of changes in land-use and land management on soil erosion and desertification risk has been studied in Messara Valley (Crete, Greece) over the last six decades (1950–2010). Vegetation cover and land-use have been analyzed using representative aerial photographs and ortho-photomaps for representative dates. Soil attributes have been described in a semi-detailed survey in 2010. Soil erosion rates and desertification risk have been assessed for each period using the PESERA and TERON models and the MEDALUS methodology, respectively. Based on distinct socio-ecological characteristics of the area three major time intervals have been identified. Cereals extensively cultivated during the first time interval were progressively replaced by olive plantations and vineyards in the following periods. Soil erosion due to water runoff was important especially in the olive transition period, declining in the olive subsidy period. However, tillage erosion became an important degradation process especially in the olive subsidy period due to mechanization of the agriculture determining soil losses ranging from 0.5 to 30 cm in sloping areas. Desertification risk due to soil erosion and land characteristics has significantly increased during the olive subsidy period

Land-use and land degradation processes affecting soil resources: Evidence from a traditional Mediterranean cropland (Greece)

Land degradation is a complex process resulting from the permanent interaction between physical and human factors. The effect of changes in land-use and land management on soil erosion and desertification risk has been studied in Messara Valley (Crete, Greece) over the last six decades (1950–2010). Vegetation cover and land-use have been analyzed using representative aerial photographs and ortho-photomaps for representative dates. Soil attributes have been described in a semi-detailed survey in 2010. Soil erosion rates and desertification risk have been assessed for each period using the PESERA and TERON models and the MEDALUS methodology, respectively. Based on distinct socio-ecological characteristics of the area three major time intervals have been identified. Cereals extensively cultivated during the first time interval were progressively replaced by olive plantations and vineyards in the following periods. Soil erosion due to water runoff was important especially in the olive transition period, declining in the olive subsidy period. However, tillage erosion became an important degradation process especially in the olive subsidy period due to mechanization of the agriculture determining soil losses ranging from 0.5 to 30 cm in sloping areas. Desertification risk due to soil erosion and land characteristics has significantly increased during the olive subsidy period

Unveiling soil degradation and desertification risk in the Mediterranean basin: a data mining analysis of the relationships between biophysical and socioeconomic factors in agro-forest landscapes

Soil degradation and desertification processes in the Mediterranean basin reflect the interplay between environmental and socioeconomic drivers. An approach to evaluate comparatively the multiple relationships between biophysical variables and socioeconomic factors is illustrated in the present study using the data collected from 586 field sites located in five Mediterranean areas (Spain, Greece, Turkey, Tunisia and Morocco). A total of 47 variables were chosen to illustrate land-use, farm characteristics, population pressure, tourism development, rainfall regime, water availability, soil properties and vegetation cover, among others. A data mining approach incorporating non-parametric inference, principal component analysis and hierarchical clustering was developed to identify candidate syndromes of soil degradation and desertification risk. While field sites in the same study area showed a substantial similarity, the multivariate relationship among variables diverged among study areas. Data mining techniques proved to be a practical tool to identify spatial determinants of soil degradation and desertification risk. Our findings identify the contrasting spatial patterns for biophysical and socioeconomic variables, in turn associated with different responses to land degradation

Assessing the effectiveness of sustainable land management policies for combating desertification: A data mining approach.

This study investigates the relationship between fine resolution, local-scale biophysical and socioeconomic contexts within which land degradation occurs, and the human responses to it. The research draws on experimental data collected under different territorial and socioeconomic conditions at 586 field sites in five Mediterranean countries (Spain, Greece, Turkey, Tunisia and Morocco). We assess the level of desertification risk under various land management practices (terracing, grazing control, prevention of wildland fires, soil erosion control measures, soil water conservation measures, sustainable farming practices, land protection measures and financial subsidies) taken as possible responses to land degradation. A data mining approach, incorporating principal component analysis, non-parametric correlations, multiple regression and canonical analysis, was developed to identify the spatial relationship between land management conditions, the socioeconomic and environmental context (described using 40 biophysical and socioeconomic indicators) and desertification risk. Our analysis identified a number of distinct relationships between the level of desertification experienced and the underlying socioeconomic context, suggesting that the effectiveness of responses to land degradation is strictly dependent on the local biophysical and socioeconomic context. Assessing the latent relationship between land management practices and the biophysical/socioeconomic attributes characterizing areas exposed to different levels of desertification risk proved to be an indirect measure of the effectiveness of field actions contrasting land degradation