Climate stability and societal decline on the margins of the Byzantine empire in the Negev Desert

Abstract

Understanding past human settlement of inhospitable regions is one of the most intriguing puzzles in archaeological research, with implications for more sustainable use of marginal regions today. During the Byzantine period in the 4 th century CE, large settlements were established in the arid region of the Negev Desert, Israel, but it remains unclear why it did so, and why the settlements were abandoned three centuries later. Previous theories proposed that the Negev was a "green desert" in the early 1 st millennium CE, and that the Byzantine Empire withdrew from this region due to a dramatic climatic downturn. In the absence of a local climate archive correlated to the Byzantine/Early Islamic transition, testing this theory has proven challenging. We use stable isotopic indicators of animal dietary and mobility patterns to assess the extent of the vegetative cover in the desert. By doing so, we aim to detect possible climatic fluctuations that may have led to the abandonment of the Byzantine settlements. The findings show that the Negev Desert was not greener during the time period under investigation than it is today and that the composition of the animals' diets, as well as their grazing mobility patterns, remained unchanged through the Byzantine/Early Islamic transition. Favoring a nonclimatic explanation, we propose instead that the abandonment of the Negev Byzantine settlements was motivated by restructuring of the Empire's territorial priorities.Over the last 12,000 years, the Negev Desert in southern Israel has hosted an arid to hyper-arid climate, but despite the harsh living conditions, people have periodically established settlements here that have persisted for centuries 1,2 . Ongoing debate has seen archaeologists, historians, and climate scientists speculate whether the rise and fall of human habitation was caused by fluctuations in climatic conditions, or whether it was primarily driven by changes in the socio-political organization of the communities living in these environmentally marginal areas 3-7 . Palaeoenvironmental studies have contributed to this debate by providing a long-term perspective on climate fluctuations in the region. However, in order to understand the human response to these patterns on short-term (i.e. centennial) scales and ground the trends in specific micro-regional settings, archaeological proxies need to be studied from contexts that bracket the cultural events under consideration 8 .One of the most significant phases of population expansion in the Negev Desert started in the 3 rd century BCE with the establishment of the Nabatean kingdom. After the kingdom was annexed and subsumed into the Roman empire in 106 CE, it reached its height with the spread of Christianity during the Byzantine period in the 4 th -6 th century CE and was subsequently abandoned around the time of the Muslim conquest of the region in the 7 th century CE 9,10 . Between the 4 th -7 th centuries CE, five major Byzantine settlements -Elusa (Halutza), Subeita (Shivta), Nessana (Nitzana), Avdat (Oboda)...

The rise and fall of viticulture in the Late Antique Negev Highlands reconstructed from archaeobotanical and ceramic data

“…Regarding the decline, grapevines grown in experimental reconstructions of ancient runoff farming in the Negev Highlands have been demonstrated to survive individual drought years (33), which inevitably occurred over the period of peak viticulture in the fifth to mid-sixth centuries. On the other hand, current evidence does not support major long-term climate change in the Negev over the Byzantine-Umayyad period (92). However, intense decadal-scale climatic change affecting the Late Byzantine decline in the Negev Highlands is plausible.…”

Byzantine—Early Islamic resource management detected through micro-geoarchaeological investigations of trash mounds (Negev, Israel)

“…At Nessana, the disposal of potentially valuable fertilizer implies there was little incentive to ensure the profitability of agriculture beyond domestic needs, which we see as a community-scale response to disruption and restructuring within the commercial agriculture sector paired with the expansion of village-tethered herding in the heartland [ 20 , 26 , 44 , 86 , 89 ]. Recent research is now indicating that agropastoral practices were likely not heavily influenced by climate change or pronounced environmental degradation [ 20 , 37 ]. Another type of disruption is recorded in the Nessana papyri (512–689 CE).…”

“…Caves in the Highlands have not formed speleothems over the past 86,000 years, indicating long-term annual precipitation levels not exceeding 200–275 mm [ 36 ]. Recent stable isotope analyses of sheep and goat teeth from the Negev also indicate unchanging forage quality through the Byzantine and Early Islamic periods, which is suggestive of climatic stability [ 37 ]. Lithosols, reg soils, and calcic soils have been forming across the region since at least the end of the Pleistocene [ 26 , 38 ].…”

“…The installation of dovecotes at the Byzantine farming villages of Shivta and Sa‘adon strongly implies the use of animal wastes as fertilizers [ 24 , 45 ; see 57 , 58 for information on Transjordan use]. Ovicaprine (sheep/goat) herding was also an important sector of the economy [ 11 , 37 , 44 ]. It stands to reason that the wide availability of ovicaprine dung made this material a valuable fertilizer as well.…”

Mediterranean precipitation isoscape preserved in bone collagen δ2H

“…The isotopic variation in precipitation can be incorporated into biological tissues and serve as a tracer of location, as exemplified by δ 2 H in bird feather keratin used for geo-location of the origin of migrant birds 10,11 , δ 2 H and δ 18 O variation in human hair keratin with water variation 12 , and δ 18 O in tooth enamel apatites used to distinguish non-local individuals 13 . Herding strategies and vegetation variation have also been investigated with time-resolved δ 18 O values of tooth enamel 14 . In contrast, organic H and organic O in bone collagen have not been developed as a geo-location tool, with the exception of an early study on deer 15 .…”