What Drives Gullies in Spain's Olive Landscapes? A regional analysis of gully activity

Data of research work "What Drives Gullies in Spain's Olive Landscapes? A Regional Analysis of Gully Activity" Figure 1: (a) Guadalquivir basin in Andalusia (Spain) (b) study area, one within each of the principal landscapes units occupied by olive groves and the meteorological stations (c) area occupied by olive groves in Andalusia (SIOSE) Figure 2: Graphic illustration of gully activity over the three study periods, showing three scenarios (NG is new gullies, SG is stable gully, AG is active gully, X indicates no gully presence, NON). Scenario a) In 2008-2010 there is no gully, in 2010-2013 a new gully appears (NG) and the gully head remains in the same position in 2013-2019 (SG); Scenario b) A gully head is mapped in the same position in all photos from 2008 to 2019, so the gully remains stable (SG) over all three study periods, Scenario c) A gully emerges (NG) in 2008-2010 and grows in 2010-2013 and in 2013-2019. This gully is considered active in the last two periods (AG) Figure 3: Observed gully heads in the years 2008, 2010, 2013 and 2019 for each landscape unit: a) countryside foothills, b) countryside hills, c) mid mountains and d) valley plains. Each study area occupies 25 km2. Figure 4: Gully Head Initiation (GHI) index for the four gully head activity types (AG - active gullies, SG - stable gullies, NG - new gullies, and NON- non-gullies) in the 4 landscape units and for the entire data set (without differentiation between landscapes). The line dividing the box represents the median value. Figure 5: Comparing GHI across three different time periods of the study period. (AG - active gullies, SG- stable gullies, NG -new gullies, and NON-non-gullies) Figure 6: (a) ROC and its corresponding AUC for each combination between the 3 point categories, taking into account all the landscapes together. (b) AUC for the entire model together, taking into account all the points that are gullies compared to those that are not. 0: Non gullies, NON; 1: New gullies NG; 2: Active gullies AG; 3: Stable gullies, SG Figure 7: Topographic threshold for gully initiation applied to the 4 four classes of gully erosion activity: SG = Stable gullies, NG = New gullies, AG = Active gullies, NON = Not gullies.