Living in Sangiran: A spatial reconstruction of hominin environment in Java at 1 Ma

Abstract

This study focuses on analysing and testing the relationship between Homo erectus behaviour and environmental dynamics in Sangiran, Java, at the time around 1 Ma. Here, palaeoenvironmental conditions encountered by Homo erectus in Java at 1 Ma were reconstructed using multiple methods. High resolution palaeotopography and coastlines, palaeoclimatic, as well as palaeovegetation maps are produced in this study for the eastern part of Java, where the majority of hominin fossils was found. After correcting for tectonic elevation changes and eustatic sea-level changes, which sum up to a marine regression of −41.8 m, the palaeotopography map shows a significant extension of land surface in the northern and eastern parts of the palaeoisland. As a palaeoclimatic indicator drought categories are used here, derived from the proportion between the number of dry and wet months according to monthly mean precipitation. Drought, i.e. the length of dry season, is the main driver of lowland vegetation distribution. Palaeotopography and paleoclimatic estimates were combined to develop a palaeovegetation map based on the topographic and climatic restrictions of modern vegetation units. In eastern Java, lowland monsoonal forests dominated the landscape at 1 Ma. These results provide for the first time a spatial sense of how topography and hydrology, rainfall patterns and vegetation units could have been distributed in the palaeolandscape of Sangiran Homo erectus.