Our understanding about the regional variation of Sediment Yield (SY) in Europe and its scale dependency currently relies on a limited number of data for mainly larger river systems. SY is the integrated result of all erosion and sediment transporting processes operating in a catchment and is therefore of high value for environmental studies and monitoring purposes. Most global assessments of SY consider catchment area (A), climate and topography as the main explanatory variables. However, it is still unclear if these factors also control regional variations of SY within Europe. This paper aims at bridging this gap. Therefore, we i) present a large database of SY-values which was constructed through an extensive literature review; ii) describe the spatial patterns of SY across Europe; and iii) explore its relation with A, climate, and topography. In total, sediment yield data from 1794 different locations throughout Europe were collected (507 reservoirs and 1287 gauging stations), representing a minimum of 29,203 catchment-year data. Only SY-data measured at gauging stations or derived from reservoir siltation rates over a period of a minimum of one year were included in the database. This database comprises a large range of catchment areas (A): i.e from small upland catchments (≥0.01 km²) to major European river basins (≤1,360,000 km²). An overview of the collected SY-data is provided and sources of uncertainty on the available data are discussed. Despite potentially large uncertainties on several of the individual SY-values, analysis of this database indicates clear spatial patterns of SY in Europe. The temperate and relatively flat regions of Western, Northern and Central Europe generally have relatively low SY-values (with ca. 50% of the SYb 40 t km −2 yr −1 and ca. 80% of the data b 200 t km −2 yr −1 ), while Mediterranean and Mountainous regions generally have higher SY-values (with around 85% of the SY-data N 40 t km −2 yr −1 and more than 50% of the data N 200 t km −2 yr −1 ). These differences are attributed to a combination of factors, such as differences in climate, topography, lithology and land use. Although larger differences in SY were found between the climatic regions than between topographic zones, it is currently difficult to identify the individual importance of the various controlling factors of SY. SY-A relationships were calculated for the entire dataset and for subgroups stratified according to the measurement method (gauging stations or reservoir surveys), range of the catchment area, climatic region, topographic zone of the river outlet, and major European river system. Although typically a negative relationship between SY and A is expected due to a decrease in topsoil erosion rates on more gentle slopes and an increase in sediment deposition with an increase in catchment size, this relationship was found to be generally very weak and subject to a lot of scatter. Furthermore, results illustrate important differences in scale dependency: whereas a weak but significant negative trend is ge...

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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 implementation.

Western Anatolia is a complex assemblage of terranes, including the Sakarya Terrane and the Tauride-Anatolide Platform that collided during the late Cretaceous and Palaeogene (80-25 Ma) after the closure of the Izmir-Ankara Ocean. Determining the precise timing at which this ocean closed is particularly important to test kinematic reconstructions and geodynamic models of the Mediterranean region, and the chronology of suturing and its mechanisms remain controversial. Here, we document the Cretaceous-Eocene sedimentary history of the Central Sakarya Basin, along the northern margin of the Neotethys Ocean, via various approaches including biostratigraphy, geochronology, and sedimentology. Two high-resolution sections from the Central Sakarya Basin show that pelagic carbonate sedimentation shifted to rapid siliciclastic deposition in the early Campanian (~79.6 Ma), interpreted to be a result of the build-up of the accretionary prism at the southern margin of the Sakarya Terrane. Rapid onset of deltaic progradation and an increase in accumulation rates in the late Danian (~61 Ma), as well as a local angular unconformity are attributed to the onset of collision between the Sakarya Terrane and the Tauride-Anatolide Platform. Thus, our results indicate that though deformation of the subduction margin in Western Anatolia started as early as the Campanian, the closure of the İzmir-Ankara Ocean was only achieved by the early Palaeocene.

Indicator-based approaches are often used to monitor land degradation and desertification from the global to the very local scale. However, there is still little agreement on which indicators may best reflect both status and trends of these phenomena. In this study, various processes of land degradation and desertification have been analyzed in 17 study sites around the world using a wide set of biophysical and socioeconomic indicators. The database described earlier in this issue by Kosmas and others (Environ Manage, 2013) for defining desertification risk was further analyzed to define the most important indicators related to the following degradation processes: water erosion in various land uses, tillage erosion, soil salinization, water stress, forest fires, and overgrazing. A correlation analysis was applied to the selected indicators in order to identify the most important variables contributing to each land degradation process. The analysis indicates that the most important indicators are: (i) rain seasonality affecting water erosion, water stress, and forest fires, (ii) slope gradient affecting water erosion, tillage erosion and water stress, and (iii) water scarcity soil salinization, water stress, and forest fires. Implementation of existing regulations or policies concerned with resources development and environmental sustainability was identified as the most important indicator of land protection.

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Debate persists concerning the timing and geodynamics of intercontinental collision, style of syncollisional deformation, and development of topography and fold-and-thrust belts along the >1,700-km-long İzmir-Ankara-Erzincan suture zone (İAESZ) in Turkey. Resolving this debate is a necessary precursor to evaluating the integrity of convergent margin models and kinematic, topographic, and biogeographic reconstructions of the Mediterranean domain. Geodynamic models argue either for a synchronous or diachronous collision during either the Late Cretaceous and/or Eocene, followed by Eocene slab breakoff and postcollisional magmatism. We investigate the collision chronology in western Anatolia as recorded in the sedimentary archives of the 90-km-long Sarıcakaya Basin perched at shallow structural levels along the İAESZ. Based on new zircon U-Pb geochronology and depositional environment and sedimentary provenance results, we demonstrate that the Sarıcakaya Basin is an Eocene sedimentary basin with sediment sourced from both the İAESZ and Söğüt Thrust fault to the south and north, respectively, and formed primarily by flexural loading from north-south shortening along the syncollisional Söğüt Thrust. Our results refine the timing of collision between the Anatolides and Pontide terranes in western Anatolia to Maastrichtian-Middle Paleocene and Early Eocene crustal shortening and basin formation. Furthermore, we demonstrate contemporaneous collision, deformation, and magmatism across the İAESZ, supporting synchronous collision models. We show that regional postcollisional magmatism can be explained by renewed underthrusting instead of slab breakoff. This new İAESZ chronology provides additional constraints for kinematic, geodynamic, and biogeographic reconstructions of the Mediterranean domain.

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