Causes and effects of diversified human impact in the Nida basin in the Roman period (Holy Cross Mts., Poland)

Abstract The authors present examples of detailed studies from the Nida River valley, against the background of climatic fluctuations in Europe. They document a very clear, although not determining, multidirectional impact of climate changes in the Roman period on the settlements and the activity of the Przeworsk culture community. Local factors were also playing an important role in this field. The ecumene of the Przeworsk culture people in southern Poland was not homogeneous, which resulted in regional differences in human impact recorded in forms and sediments. It consisted of ‘centres’ of non-agricultural production area. One was the metallurgical region in the Holy Cross Mts., the second was pottery centre in the Vistula River valley, east of Kraków – both relatively densely populated and with significant human impact on the environment. Between these centres (occupying relatively small areas) there were vast areas used for agriculture – a mosaic of arable land, pastures, and forests, which resulted in low-intensity erosion and accumulation processes. The heterogeneity of the ecumene with varying attractiveness could result in migration movements related not only to great migrations of the Przeworsk culture population southward but also to regional and local migrations towards both production centres from areas less favourable to agriculture (analogical modern ‘village→town’ migrations). This migration could have led to the decline in the population density of some agricultural areas, e. g. the Nida River valley and its left-bank, karst part of the catchment, after the Roman Climate Optimum (after 150 AD).