摘要：This study investigates how medium-term gully-development data differ from short-term data, and which factors areresponsible for their spatial and temporal variability. Eight actively retreating bank gullies situated in Spanish basin landscapeswere monitored for up to 11 years with high-resolution aerial photographs using unmanned remote-controlled platforms. Theresults of planimetric and volumetric change analysis using GIS and photogrammetry systems show a high variability of annualgully retreat rates both between gullies and between observation periods. The varying influences of land use and human activitieswith their positive or negative effects on runoff production and connectivity appears to play the most important role inthese study areas, both for short-term variability and medium-term difference in gully development. The study demonstratesthe importance of capturing spatially continuous, high-resolution three-dimensional data for detailed gully monitoring. It alsoconfirms that short-term data are not representative of longer-term gully development, but they are still required to understandthe processes – particularly human activity at varying time scales – causing gully-erosion variability.
关键词：gully erosion; monitoring; small-format aerial photography; land degradation; semi-arid regions
