Tree Forensics: Modern DNA barcoding and traditional anatomy identify roots threatening an ancient necropolis

Abstract

Societal Impact Statement Ancient burial caves represent some of the most important sources of information on human history. In a world heritage site in Israel, such caves are under threat due to tree root growth penetrating from the ceilings and causing a risk of cave collapse. To facilitate historical conservation, while avoiding cutting of the mixed forest above the caves, we identified the tree species responsible for the damage, facilitating their specific cutting. Accurate identification of tree roots balances the needs to protect human structures on one side, while conserving the majority of vegetation on the other. Our approach is applicable to the management of ancient sites, as well as to urban management more broadly. Summary Tree roots have penetrated the ceiling of burial caves in a ~1,800‐years‐old necropolis in the Galilee, Israel, damaging the antiquities and risking the catacombs with collapse. Root identification was needed to enable selective cutting (at the species level), facilitating the conservation of the world heritage site, while maintaining the majority of trees growing on top of the burial caves. Samples of roots penetrating the cave ceilings were collected and identified both by using DNA barcoding, which has become a standard method for the reliable identification of organisms in their natural environment, and also by traditional morpho‐anatomical methods. However, woody plant species of the Mediterranean region are under‐represented in DNA databases. Therefore, we added relevant species to the ITS2 database by sequencing the internal transcribed spacer (ITS)2 of the 18S‐26S rDNA from sampled leaves of 19 woody species of the Mediterranean maquis. The identification of these tree species facilitated their selective removal, balancing antiquities, and nature conservation needs.

Keywords

• antiquities
• Beit She'arim
• conservation
• ITS2
• tree roots