"Evolution Canyon" in Upper Galilee: Microgeographical, ecological, and evolutionary model of plant and beetle species diversity in Nahal Keziv

Research that has been conducted in the last year in Lower Nahal Keziv aims to examine the similarity and differences with the "Evolution Canyon" model developed in Lower Nahal Oren. The working site of Nahal Kziv is 38 km north of Nahal Oren, near Moshav Manot. The south-facing slope (SFS) changes from a Calicotome villosa and Salvia fruticosa gangue in the lower part to a Gramineae savannah in the upper part. The north-facing slope (NFS) is an Acer obtusifolium and Laurus nobilis forest, homogenous along the whole slope. This significant interslope differential caused by the higher solar radiation on SFS provides a microgeographical model of macroscale evolutionary phenomena, such as species distribution, divergence, and migration. The similarity of the microgeographical conditions between Nahal Kziv and Nahal Oren allows us to compare the sites and expand the model. A Whittaker plant sampling shows substantial differences between the slopes: 203 species were found on SFS, almost 60% of them annuals, compared to 53 species found on NFS, of which only 7.5% were annuals (p < 0.001). The overlap between the slopes is small. Similar phenomena, albeit less pronounced, were found in Lower Nahal Oren. Beetles were collected by pitfall traps and nets. Preliminary results show that Nahal Kziv harbors Carabus (Carabidae) species and subspecies that have a more northerly distribution pattern than those found in Lower Nahal Oren.