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

Ilan Stavi,Eli Argaman,Tamir Rozenberg,Ashraf Al-Ashhab,Elli Groner

doi:10.3390/w10101400

Ilan Stavi, Eli Argaman + Show 3 more

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https://doi.org/10.3390/w10101400

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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.

Highlights

Ancient agricultural stone terraces are widespread around the Mediterranean Basin [1]
Our results accord with García-Ruiz and Lana-Renault [38], who reviewed numerous studies from the Mediterranean region of Europe and found that terraced land abandonment had led to the encroachment of trees and shrubs
Agricultural land abandonment and lack of maintenance have led to the failure and collapse of many terraces

Summary

Introduction

Ancient agricultural stone terraces are widespread around the Mediterranean Basin [1]. The gradual addition of stone layers—necessary to keep the stones’ upper rim above the aggrading field surface—has led to the formation of walls. Many times, these multilayer constructions were built with a cross-section staircase shape, which simultaneously provided the structure with greater strength and allowed gradual cascading of excess water, preventing undercutting and erosion [3]. The terraces enable the stream’s gradient diminishing and bed widening [2], while in hillslopes, the terraces cause surface leveling [4].

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