Failure and Collapse of Ancient Agricultural Stone Terraces: On-Site Effects on Soil and Vegetation

Abstract

Ancient agricultural stone terraces, dated to the Roman and Byzantine ages, are prevalent across the Negev drylands of Southern Israel. The goal of these structures was to reduce hydrological connectivity by harvesting water runoff and controlling soil erosion, thus allowing cultivation of cereals. Land abandonment and the lack of maintenance have led to the failure and collapse of many of these stone terraces. The objective of this study was to assess the effect of failure and collapse of terraces on the on-site (on-field) geo-ecosystem functioning, as determined by vegetation cover and soil quality parameters. This was achieved by studying vegetal and soil properties in shrubby vegetation patches and inter-shrub spaces of intact-terrace plots and collapsed-terrace plots, as well as in the surrounding ‘natural’ lands. Mean cover of both shrubby and herbaceous vegetation was highest in intact terraces, intermediate in ‘natural’ lands, and lowest in collapsed terraces. The overall soil quality followed the same trend as the vegetation cover. Additionally, this study shows that the anthropogenic impact on geo-ecosystem functioning can be either beneficial or detrimental. While well maintained stone terraces benefit the soil and vegetation, abandoned and unmaintained terraces may result in accelerated soil erosion and land degradation.