Soil formation, distribution, and vegetation interplays at Lions Rump, Maritime Antarctica

Abstract

The objective was to study soil formation and to analyze the relationships between soil distribution and vegetation cover at Lions Rump, King George Island, Maritime Antarctica. WRB and Soil Taxonomy systems were applied in association with geomorphological features. Thirteen pedons were sampled and described for their physical, chemical, and mineralogical attributes. Soil mapping and vegetation distribution were performed. Results showed that soils are mainly formed from weathered basalt-andesitic rocks, which are naturally rich in apatite, and have a high P background. Typic Dystrogelepts ornithic and Typic Gelorthents ornithic are the main ornithogenic soils in the study area. Typic Dystrogelepts ornithic represent the deepest, most structured, and reddish soils at Lions Rump. Typic Haplogelepts ornithic are the main soils on the first and second moraine levels from White Eagle Glacier. Typic Haploturbels and Lithic Haploturbels are present just above 80 m a.s.l. (above sea level), especially on the top areas and paraglacial spots, with gelic materials within 100 cm of the soil surface and permafrost within 200 cm. Despite occurring only at higher altitudes, they represent the most extensive soil cover at Lions Rump. Turbic Haplogelepts and Typic Haplorthents occur between 40 and 80 m a.s.l., without the influence of bird nesting and with permafrost absent to a depth of 200 cm. Vitrandic Cryopsamments and Oxyaquic Cryopsamments dominated the first level of terraces and former beaches along the coastal area. Other soils, classified as Lithic Cryorthents Ornithic and Typic Gelifluvents ornithic, occur in very restricted areas: the former on sea stack rock outcrops (basaltic plugs) near the beach, and the latter in a small portion of glacial alluvial fans. Overall, soil distribution and classification in Lions Rump allowed the identification of two main soil domains: Ornithogenic soils (without permafrost) and the Gelisols (above 80 m a.s.l.). Higher P and N contents at ornithogenic sites favor vegetation establishment with the presence of Deschampsia antarctica and Colobanthus quitensis.