Evaluation and selection of indicators for land degradation and desertification monitoring : methodological approach

International audienceAn approach to derive relationships for defining land degradation and desertification risk and developing appropriate tools for assessing the effectiveness of the various land management practices using indicators is presented in the present paper. In order to investigate which indicators are most effective in assessing the level of desertification risk, a total of 70 candidate indicators was selected providing information for the biophysical environment , socioeconomic conditions, and land management characteristics. The indicators were defined in 1,672 field sites located in 17 study areas in the Mediterranean region, Eastern Europe, Latin America, Africa, and Asia. Based on an existing geo-referenced database, classes were designated for each indicator and a sensitivity score todesertification was assigned to each class based on existing research. The obtained data were analyzed for the various processes of land degradation at farm level. The derived methodology was assessed using independent indicators, such as the measured soil erosion rate, and the organic matter content of the soil. Based on regression analyses, the collected indicator set can be reduced to a number of effective indicators ranging from 8 to 17 in the various processes of land degradation. Among the most important indicators identified as affecting land degradation and desertification risk were rain seasonality, slope gradient,plant cover, rate of land abandonment, land-use intensity, and the level of policy implementation

MORPHOTECTONICS OF THE PSATHOPYRGOS ACTIVE FAULT, WESTERN CORINTH RIFT, CENTRAL GREECE

Η περιοχή μελέτης είναι στο δυτικό άκρο του Κορινθιακού ανοίγματος. Ο Κορινθιακός κόλπος αποτελεί χαρακτηριστικό παράδειγμα νεοτεκτονικού βυθίσματος στον Ελληνικό χώρο. Το βύθισμα αυτό δημιουργήθηκε από την δράση μεγάλων ρηγμάτων τα οποία ανοίγουν τον φλοιό κατά την διεύθυνση Β-Ν. Με βάση το ψηφιακό υψομετρικό μοντέλο της περιοχή,ς υπολογίστηκαν τέσσερις μορφοτεκτονικοί δείκτες (υψομετρικό ολοκλήρωμα, ασυμμετρία L·κάvης απορροής, λόγος πλάτους κοιλάδας προς ύψος, και ο δείκτης κλίσης). Επίσης χρησιμοποιώντας το ψηφιακό μοντέλο εδάφους, δορυφορικές εικόνες από τον σαρωτή ΕΤΜ+ του δορυφόρου Landsat 7 και δεδομένα SRTM, έγινε η ψηφιοποίηση των ρηγμάτων της περιοχής μελέτης. Στην συνέχεια, η μελέτη της τεκτονικής γεωμορφολογίας της περιοχής έγινε με χρήση θεματικών χαρτών, οι οποίοι απεικόνιζαν την χωρική κατανομή των δεικτών. Στην εργασία αυτή μελετήθηκε ιδιαίτερα το κανονικό ρήγμα του Ψαθόπυργου το οποίο λειτουργεί ως μία ενιαία, ενεργή δομή μήκους 16 χιλιομέτρων.The study area is located on the western part of the Gulf of Corinth which is considered as a paradigm of an active rift system in Greece. This rift was formed by normal slip on big faults which extend the crust of the Earth in the N-S direction. The morphotectonic indices (hypsometric curve, hypsometric integral, drainage basin asymmetry, ratio of valley floor width to valley height) have been estimated using the 20-m digital elevation model of this area and the ARC software. The normal faults of the study area have been extracted by use of a DEM mosaic of 20-m pixel size, satellite images from Landsat 7 ETM+ and SRTM 90m. Our results highlight the recent activity of the Psathopyrgos normal fault on the basis of a series of morphotectonic evidence and suggest the existence of a single fault segment for a distance of 16 km

Evaluation and Selection of Indicators for Land Degradation and Desertification Monitoring: Methodological Approach

An approach to derive relationships for defining land degradation and desertification risk and developing appropriate tools for assessing the effectiveness of the various land management practices using indicators is presented in the present paper. In order to investigate which indicators are most effective in assessing the level of desertification risk, a total of 70 candidate indicators was selected providing information for the biophysical environment, socio-economic conditions, and land management characteristics. The indicators were defined in 1,672 field sites located in 17 study areas in the Mediterranean region, Eastern Europe, Latin America, Africa, and Asia. Based on an existing geo-referenced database, classes were designated for each indicator and a sensitivity score to desertification was assigned to each class based on existing research. The obtained data were analyzed for the various processes of land degradation at farm level. The derived methodology was assessed using independent indicators, such as the measured soil erosion rate, and the organic matter content of the soil. Based on regression analyses, the collected indicator set can be reduced to a number of effective indicators ranging from 8 to 17 in the various processes of land degradation. Among the most important indicators identified as affecting land degradation and desertification risk were rain seasonality, slope gradient, plant cover, rate of land abandonment, land-use intensity, and the level of policy implementatio

A global standard for monitoring coastal wetland vulnerability to accelerated sea-level rise

10.1038/nclimate1756Nature Climate Change35458-46