Impacts of mid- to late-Holocene land use on residual hill geomorphology: A remote sensing and archaeological evaluation of human-related soil erosion in central Karnataka, South India

Abstract

This paper describes the impacts of Neolithic Period ( c. 5000–3200 cal. BP) and Iron Age ( c. 3200–2300 cal. BP) occupation and land use on the geomorphology of residual hills that punctuate an expansive planation surface in central Karnataka, South India. Analyses of archaeological survey data, soil and regolith profiles, remotely sensed metrics of hill morphology and distributions of soil and sediment, and paleoecological data indicate that cultural land use altered the morphology of these features and the distribution of soils on them, and consequently impacted the processes by which they continued to develop. Statistical regression models indicate that archaeological evidence for ancient land use is a significant explanatory variable for the proportion of remaining soil cover and exposed residual rock on the sampled hills. Moreover, multivariate regression models explaining soil removal on the hills are effective when including archaeological proxies for ancient land use along with other geomorphological variables. The combined effects of intensified agro-pastoral land use, vegetation changes, and variations in climatic humidity during the mid-Holocene to late Holocene appear to have facilitated erosional conditions that outpaced subsurface weathering. These findings imply that the refinement of models for the development of residual hills in South India, where early paradigms for explaining the evolution of such landforms were formalized, should consider the effects of Holocene land use where applicable. The findings also suggest that recent efforts to understand the unique ecology of these landforms should account for historical human land use.