Blame it on the goats? Desertification in the Near East during the Holocene

Abstract

The degree to which desertification during the Holocene resulted from climatic deterioration or alternatively from overgrazing has puzzled Quaternary scientists in many arid regions of the world. In the research reported upon here, a multi-disciplinary investigation of a 5-m deep, ~11,000-year-old sediment column excavated in a dry lake bed in southern Jordan revealed an early interval in which proxies of plant cover and sheep/goat stocking rates co-varied directly with climatic cycles. Beginning ~5.6 kcal BP, however, this pattern changed with fecal spherulite and phytolith densities failing to co-vary and with spherulites often greatly exceeding phytolith densities, which we suggest is indicative of overgrazing. Moreover, the lack of agreement between the high phytolith densities and other indicators of a desert landscape (i.e. geomorphic and palynologic) suggests that phytolith densities were inflated by fodder subsidies and as such are not entirely reflective of plant cover for this later interval. Given the co-incidental emergence of overgrazing with archaeological evidence for a marked rise in regional population, emergence of widespread trade, and expansion of the Timnian pastoral complex during Chalcolithic–early Bronze times, we argue that desertification was a consequence of socio-economic factors (e.g. higher stocking rates) associated with a shift from a subsistence to a market economy. In addition, we contend that the signature lithic artifact variety (tabular scraper) that appeared in great abundance during this period was directly tied to the emergent market economy and its secondary products (wool) in having been used to shear sheep. Moreover, in that these changes took place largely concurrent with local and regionally recognized evidence of a moist interval, we conclude that the mid- to late-Holocene desertification of the southern Levant was induced more by anthropogenic than climatic factors.

Collapse and continuity: A multi-proxy reconstruction of settlement organization and population trajectories in the Northern Fertile Crescent during the 4.2kya Rapid Climate Change event

“…Higher stocking rates may have led to ecological degradation and desertification associated with overgrazing. Desertification as a result of overgrazing has been recorded in dryland environments across the world [ 77 and references therein], including in the modern Levant [ 78 ] and in Late Chalcolithic and Early Bronze Age Jordan, again linked to overstocking for commercialized textile production [ 79 ]. Within our study area, land use reconstructions based on archaeobotanical data have shown an increase in desert-steppe environments in the Jazira during the Middle Bronze Age (4,000–3,800 cal BP) when compared to the Early Bronze Age (5,000–4,000 cal BP), attributed to ecological degradation caused by both overgrazing and agricultural intensification [ 80 ].…”

“…Higher stocking rates may have led to ecological degradation and desertification associated with overgrazing. Desertification as a result of overgrazing has been recorded in dryland environments across the world[77 and references therein], including in the modern Levant[78] and in Late Chalcolithic and Early Bronze Age Jordan, again linked to overstocking for commercialized textile production[79].…”

The Eneolithic/Bronze Age Transition at Tegole di Bovino (Apulia): Geoarchaeological Evidence of Climate Change and Land-Use Shift

“…Rapid anthropogenic deforestation and/or overgrazing of soils in the context of progressive reduction of water availability [94] may have enhanced the effect of surface processes leading to the dismantling and removal of the pristine Holocene soil cover. Elsewhere, prehistoric and historical records point to the coupled effect of climatic changes-triggered surface processes and human agency as a major cause of soil loss [14,15,29,[95][96][97][98][99][100].…”

Late Holocene landscape instability in the Breckland (England) drift sands

“…The causes and extent of the drift sand landscape instability phases are currently not well understood for either European drift sand landscapes nor desertification (e.g. Fanta and Siepel, 2010;Henry et al, 2017). In part, this is because understanding causes and effects through time and space when there are multiple variables, each with their own leads and lags, is a not trivial exercise.…”

“…Landscape instability of the drift sands as well as desertification processes have been variously attributed to climate, growing population pressure, agricultural overexploitation, increased mobility and usage of roads during the later Middle Ages (Castel, 1991;Cordova, 2007;Derese et al, 2010;Heidinga, 2010;Koster, 2010;Rosen, 2011;Fan et al, 2016;Henry et al, 2017;Pierik et al, 2018). For the European coversand belt it was originally thought that drift sand phases increased significantly after 1200 AD (Castel, 1991;Koster, 2010;Vera, 2011).…”