Gerbil bones attest to successful Byzantine agriculture in the Negev

A large accumulation of bones belonging to Meriones tristrami, also known as Tristram’s jird, a species of gerbil common to the Middle East, which were found in the ancient Byzantine agricultural fields in the northern Negev, are the first biological evidence of thriving agriculture there some 1,500 years ago, according to a study of the University of Haifa published Journal of the Royal Society of Sciences.

Accumulation of gerbil bones discovered in the northern Negev [Credit: Prof. Guy Bar-Oz]

Researchers Tal Fried, Lior Weissbrod, Yotam Tepper, Guy Bar-Oz, of the University of Haifa’s Archaeology Department, write that “it is widely believed that Byzantine agriculture in the Negev Desert (fourth to seventh century CE), with widespread construction of terraces and dams, altered local landscapes. However, no direct evidence in archaeological sites yet exists to test this assumption.

“We uncovered large amounts of small mammalian remains (rodents and insectivores) within agricultural installations built near fields, providing a new line of evidence for reconstructing anthropogenic impact on local habitats.

“Abandonment layers furnished a high abundance of remains, whereas much smaller numbers were retrieved from the period of human use of the structures. Digestion marks are present in low frequencies (20% of long bones and teeth), with a light degree of impact, which indicate the role of owls (e.g. Tyto alba) as the principal means of accumulation.”

“The most common taxa—gerbils (Gerbillus spp.) and jirds (Meriones spp.)—occur in nearly equal frequencies, which do not correspond with any modern Negev communities, where gerbils predominate in sandy low-precipitation environments and jirds in loessial, higher-precipitation ones. Although low-level climate change cannot be ruled out, the results suggest that Byzantine agriculture allowed jirds to colonize sandy anthropogenic habitats with other gerbilids and commensal mice and rats.”

A Tristam’s jird (Meriones tristami) poking its head out of its burrow [Credit: Dûrzan cîrano/WikiCommons]

Remains of rodents and insectivores from archaeological sites have been used for reconstructing environmental conditions surrounding ancient settlements, the researchers reported. Small rodents and shrews in the Negev, which include a preponderance of dry-adapted species of gerbils and jirds (Gerbillidae), have generally adjusted to conditions of water and food shortages along with the high temperatures.

The main water supply for most species in this arid environment is from ingested food. With their dry land adaptations, most of these species remain hidden during the day in cooler and more humid shelters. Micromammals are present in a wide variety of habitats in the Negev and are considered especially sensitive to environmental variation. Their community structure is thought to respond to factors such as variation in precipitation or soil type and their influence on vegetation covers over relatively small scales.

Research based on live-trapping of small mammals in the Negev and analysis of prey remains in pellets of owls (Strigiformes) demonstrated consistent habitat associations of local species. Both habitat features (e.g. soil type, rockiness and proportion of vegetation cover) and proximity to different types of anthropogenic habitats were shown to influence species composition.

Data from owl pellets also showed a strong impact of recent anthropogenic landscape change on community composition owing to modern settlement and agriculture.

Internal pillar with rows of pigeon nest compartments [Credit: Prof. Guy Bar-Oz]

Other studies of owl pellets showed that in more remote parts of the Negev, prey composition is more diverse and consists mainly of wild species (non-commensal), mainly gerbilids.

“Based on our findings, species of jirds and gerbils formed a substantial component of ancient ecological communities of agro-ecosystems in the Negev, testifying to the environmental impact of Byzantine agriculture,” the researchers concluded.

“Although Byzantine occupation of the Negev did not achieve the scale of modern human influence of industrialized farming, it undoubtedly exerted lasting impacts which altered ecological conditions and the structure of local plant and animal communities. Reconstructing the patterns of ancient human landscape transformation in greater detail will require additional trapping and owl pellet studies in modern non-industrial agricultural settings in the Negev. It is possible that localized anthropogenic impacts in the Negev were further augmented by regional climate fluctuations, though additional and more detailed palaeo-environmental data obtained directly from archaeological sites will be needed to assess this possibility.”

Source: The Jewish Press [January 12, 2018]