Unprecedented yet gradual nature of first millennium CE intercontinental crop plant dispersal revealed in ancient Negev desert refuse

Roughly 50,000 quantifiable macroscopic plant parts were retrieved from fine-sifted flotation and dry-sieved sediment samples of the middens of Elusa, Shivta, and Nessana, excluding charcoal and in addition to a roughly equal number retrieved from wet-sieving. These mostly seed and fruit (carpological) remains were identified to a total of 144 distinct plant taxa (Supplementary file 1). Nearly half of the identified specimens were derived from six Shivta middens, one quarter from three Elusa middens, and one quarter from two Nessana middens. Preservation quality varied somewhat within and between middens and samples, the richest of which were the Early Islamic middens from Shivta and Nessana, which also displayed a higher diversity of finds (Supplementary file 2). However, all middens yielded rich concentrations of charred seeds and other organic remains, including many exceptionally preserved specimens. Identified species were classified as either domesticated or wild and the former were grouped by functional category (Supplementary file 1). Most of the 120 wild taxa have ethnographically documented uses, whether for forage or fodder, crafts or fuel, food or spice, medicine or recreation. Nearly all of them grow wild in the Negev Highlands today and we cannot determine for certain which were deliberately used on site. Twenty-three domesticated food plant taxa were identified by carpological remains, including cereals, legumes, fruits, nuts, and one vegetable. We focus on these plants as indicators of local foodways and global crop diffusion. Their orders of magnitude by midden context appear in Table 2, for specimens retrieved from fine-sifted samples (see Materials and methods for sampling strategy). This data enables categorization of Late Antique Negev Highland domesticates as staples, cash crops, and luxury/supplementary foods, setting the stage for analysis of the local manifestation of long-term crop diffusion.

Identified charcoal and pollen previously reported by Langgut et al., 2021 (Supplementary files 3–5) raise the number of distinct plant taxa identified in the NEGEVBYZ project to over 180. Among them, pollen of the exotic hazel (Corylus sp.)—apparently grown locally for its nuts—is included in the discussion of domesticated food plants. Doum palm (Hyphaene thebaica [L.] Mart.), which grows wild today in the southern Aravah valley, is attested by charcoal (Supplementary files 3–5) but this likely represents wild rather than domesticated specimens. Similarly, sycomore fig (Ficus sycomorus L.), which produces tasty fruits, was grown primarily for wood in ancient times (Feliks, 1968). Therefore, we exclude doum palm and sycomore fig from the discussion of domesticated food plants’ status and longer-term trajectories, but include them among the fruit trees in Supplementary file 5.

Seed quantities and ubiquity point to barley (Hordeum vulgare L.), wheat (Triticum turgidum/aestivum), and grape (Vitis vinifera L.) as the main cultivated crops, which were clearly calorific staples. Their local cultivation is attested to by cereal processing waste (rachis fragments, awn and glume fragments, culm nodes, and rhizomes) and wine-pressing waste (grape pips, skins, and pedicels). In addition, lentils (Lens culinaris Medik. syn. Vicia lens [L.] Coss. & Germ.), bitter vetch (Vicia ervilia [L.] Willd.), fig (Ficus carica L.), date (Phoenix dactylifera L.), and olive (Olea europaea L.) should also be counted as staples based on seed quantities and ubiquity (Table 4; Supplementary file 5). They too were likely cultivated locally. Significantly, all identified staples were among the Southwest Asian Neolithic founder crops and early fruit domesticates which formed a stable part of Levantine diets by the end of the Chalcolithic (c. 4500–3300 BCE).

Grapes were previously shown to be the primary cash crop of the Byzantine Negev Highlands, particularly in the mid-5^th to mid-6^th c. CE, based on their changing relative frequencies (Fuks et al., 2020b). Interestingly, free-threshing hexaploid bread wheat (Triticum aestivum s.l.)—a more market-oriented wheat species identifiable archaeologically by indicative rachis segments—appears in the Negev Highlands only after the mid-6^th c. (Table 4). This corresponds with the period of decline in viticulture (Fuks et al., 2020b).

In the ‘luxuries and supplements’ category, we include potentially important and desirable dietary components which were minor and apparently nonessential in local consumption or agriculture. These include several food crops poorly represented in the local assemblages: broad bean (Vicia faba L.), fenugreek (Trigonella foenum-graecum L.), Spanish vetchling (Lathyrus clymenum L.), and white lupine (Lupinus albus L.) among the legumes; peach (Prunus persica [L.] Batsch), plum/cherry (Prunus subgen. Cerasus/Prunus), carob (Ceratonia siliqua L.), and jujube (Ziziphus jujuba/mauritiana) among the tree-fruits; almond (Prunus amygdalus Batsch), walnut (Juglans regia L.), stone pine (Pinus pinea L.), pistachio (Pistacia vera L.) and hazel (Corylus sp.) among the nuts; aubergine (Solanum melongena L.) as a unique summer vegetable (Figures 2 and 3); and supplementary wild edibles such as beet (Beta vulgaris L.), coriander (Coriandrum sativum L.), and European bishop (Bifora testiculata [L.] Spreng.) (Supplementary file 1). The latter three grow wild in Israel today mostly north of the Negev Highlands; we count them as wild considering their small quantities and nearby distribution. Any of the above could have been cultivated in Negev Highland runoff farming or on site (Evenari et al., 1982; Langgut et al., 2021; Tepper et al., 2022).

Complementing the seed/fruit remains presented above, palynological and anthracological analyses support local cultivation of grapevine, fig, olive, date, pomegranate, carob, and the Prunus genus, which includes almond, peach, and/or plum/cherry (Langgut et al., 2021). Based on stone pine seed coats (Figure 3d), and the identification of Pinaceae pollen indicative of a pine other than the local Aleppo pine (Pinus halepensis Mill.), it is plausible that stone pine was cultivated locally, albeit on a small scale (Supplementary file 5). Pollen evidence also suggests small-scale local cultivation of hazel—an additional domesticate unattested in the Southern Levant before the Roman period (Supplementary files 4 and 5).

Another important ancient economic plant found in the assemblages is the Nile acacia (Vachellia nilotica (L.) P.J.H.Hurter & Mabb.), which does not grow today in the Negev. Previous archaeobotanical finds of Nile acacia in the Levant all come from Roman-period sites in the Dead Sea rift valley, which Kislev, 1990 interpreted as a component of the ancient flora in this area marked by pockets of Sudanian vegetation. However, this was also an important region for desert-crossing camel caravan commerce, connecting Arabia, the Red Sea, and the Mediterranean. Nile acacia seed finds from Elusa (Figure 3) are the first of their kind from outside the phytogeographic region of Sudanian vegetation, but they remain within the ancient caravan trade routes connecting the Red Sea and the Mediterranean. Therefore, we consider Nile acacia seeds to represent a Roman-period introduction to the Levant, whether as objects of cultivation or of trade at the Negev desert route sites. Other exotic trees commonly used for quality wood and craft were identified by pollen and/or charcoal, including: cedar of Lebanon (Cedrus libani A.Rich.), European ash (Fraxinus excelsior L.), and boxwood (Buxus sempervirens L.). Cedar was identified by both charcoal and pollen, suggesting local garden cultivation (see Langgut et al., 2021 and Supplementary files 3 and 4).

The Early Islamic period middens were more concentrated in plant remains, and it is in them that most of the rare domesticated species, RAD crops included, were found (Supplementary file 2). Samples containing the unique finds of white lupine and non-indigenous jujube—which are unprecedented in Southern Levantine archaeobotany—were dated to the Umayyad or early Abbasid period (mid-7^th – late 8^th c. cal. CE at 2σ; see Figure 1 and Supplementary file 6). However, historical studies have identified these species in Roman-period texts of the Southern Levant (Amar, 2000). All other RAD species found in the Negev Highlands are attested to in the Southern Levantine archaeobotanical record of the 1^st c. BCE–4^th c. CE (Supplementary file 7). The near absence of these crop species in the Negev Highland Byzantine middens compared with the Early Islamic middens is likely the result of conditions favoring deposition and preservation of archaeobotanical remains in the latter, such as a much higher concentration of apparently hearth-derived domestic waste. Therefore, we do not consider the paucity of RAD crops in the Byzantine middens to be evidence of their absence. However, one crop for which there is no pre-Islamic evidence in the Southern Levant is the aubergine. The sediment sample from Shivta containing aubergine seeds was dated to the Abbasid period (772–974 cal CE at 2σ), supporting previous finds from Abbasid Jerusalem (Amichay et al., 2019; Amichay and Weiss, 2020; Samuel, 2001).

Considering together the domestic plants evident in the Negev Highlands according to their period of first attestation in the Southern Levant, archaeobotanically and historically, offers a window onto processes of long-term crop diffusion (Supplementary file 7). While their quantities and ubiquities indicate that RAD and IGR crops were initially of minor significance, they make up over a third of the domesticated species found in the Negev Highland middens (Figure 4, Supplementary file 7). All the more surprising considering the Negev Highlands’ desert and present-day peripheral status, this new data reveals for the first time the extent of western influence on local agriculture and trade (Figure 5).