Identification, characterisation and analysis of the Oltrepo Pavese calanchi in the Northern Apennines (Italy) Alberto Bosino a, ⁎, Adel Omran b,c , Michael Maerker a a Department of Earth and Environmental Sciences, University of Pavia, Via A. Ferrata, 1, 27100 Pavia, Italy b Department of Geography, Tübingen University, Germany Rümelinstr 19-23, Tübingen, Germany c Department of Science and Mathematical Engineering, Faculty of Petroleum and Mining Engineering, Suez University, Egypt abstract article info Article history: Received 15 March 2019 Received in revised form 9 May 2019 Accepted 9 May 2019 Available online 10 May 2019 Badlands are characteristic erosional forms distributed along the entire Apennines. In the Italian context badland areas are called “calanchi”, the plural of the word “calanco”. In this paper we present the first calanchi inventory map of the Oltrepo Pavese area, Northern Apennines (Italy). In total 263 calanchi were mapped using remote sensing techniques like Orthophotos, Google Earth images, as well as field recognition. Moreover, calanchi were characterised from a geomorphologic, geologic and a morphometric point of view. The calanchi of the Oltrepo Pavese have been categorised in two geomorphological classes based on process related morphologies. In the study area calanchi mainly occur in soft sedimentary bedrock materials such as melanges, marls, claystones, and interstratified rocks. The results show that calanchi formations are often related to faults and tectonic lineaments present in the study area. Moreover, we analyse a 5 m cell size Digital Terrain Model to detect correlations between calanchi and morphometric indices. The calanchi, defined and categorised for the first time in the study area, show typical morphometric characteristics of Apennine calanchi forms and features. In partic- ular, they occur on concave south-facing slopes on soft bedrock formations. Finally, a multitemporal air photo interpretation over a 40 years period indicated a general decrease in calanchi areas. The area reduction is mainly correlated to intensive land use changes combined with variations of precipitation pattern. The revegetation trend was also confirmed by NDVI analysis based on Landsat satellites images. The calanchi were digitized and stored in a GIS database providing the information for future quantitative modelling assessments. © 2019 Elsevier B.V. All rights reserved. Keywords: Calanchi Inventory map Oltrepo Pavese (Northern Apennines) Land use change 1. Introduction Badland formations consist of a range of erosional forms and processes such as rill–interrill, piping, mass movements, as well as gully- ing, mud- and debris flows (Alexander, 1980, 1982). Badlands are consid- ered as areas endangering agricultural activities though they have important ecological functions and are hotspot areas of biodiversity i.e. Bollati et al. (2016). Thus, badlands can be seen as sensitive indicators of global change effects. Generally, badlands are characterised by steep slopes, high relief and unconsolidated material (Torri et al., 2000). However, humans play a key role in triggering the process dynamics lead- ing to badlands formation. Human impacts can be traced back to Roman times and in some areas up to the Neolithic revolution (e.g., Buccolini et al., 2007; Del Monte, 2017). Human activity influences the composition of flora and fauna (landuse) as well as soils (irrigation, fertilization, ero- sion) and potentially incides on the regional climate (global warming). In the Italian context badland areas are called “calanchi” derived from the Latin verb “chalare” meaning slowly falling or slumping down (Bucciante, 1922). The identification, characterisation and temporal as- sessment of spatial variations in calanchi areas was studied in Italy since the beginning of the last century (e.g., Bucciante, 1922; Castiglioni, 1933; Biancotti and Cortemiglia, 1982; Farabegoli and Agostini, 2000; Calzolari and Ungaro, 1998; Moretti and Rodolfi, 2000; Battaglia et al., 2002; Buccolini and Coco, 2010, 2013; Bollati et al., 2012; Caraballo-Arias et al., 2014, 2015; Coco et al., 2015; Bianchini et al., 2016; Bollati et al., 2016; Cappadonia et al., 2016; Caraballo-Arias and Ferro, 2016, 2017; Del Monte, 2017; Brandolini et al., 2018). The forma- tion of calanchi is mainly related to accelerated erosional processes (e.g., Battaglia et al., 2002) due to surface and subsurface runoff in soils often characterised by low permeability. The erosion of the substrates and soils highly depends on the presence/absence of vegetation and should therefore be accounted for in assessments of landscape degrada- tion and/or recovery (Molina et al., 2009). Over the long term, vegetation can increase soil organic matter, improve soil physical properties and re- duce soil erodibility, as well as runoff and erosion to a safe level (Zhang et al., 2015). Furthermore, the physical and chemical properties of the parent material are important factors in the development of rills and pipes (Hodges and Bryan, 1982; Faulkner et al., 2004; Vergari et al., Geomorphology 340 (2019) 53–66 ⁎ Corresponding author. E-mail addresses: alberto.bosino01@universitadipavia.it (A. Bosino), adelfouad.omran@suezuniv.edu.eg (A. Omran), michael.maerker@unipv.it (M. Maerker). https://doi.org/10.1016/j.geomorph.2019.05.003 0169-555X/© 2019 Elsevier B.V. All rights reserved. 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