Annual Meeting of the Zoological Society of Israel, 2014, Abstracts, p 15.----------------------------------------------------------------------------

The invertebrate fauna on the forest floor of a carob grove

Zvi Sever

Biology Dep., University of Indianapolis, Indiana, U.S.A

sev@netvision.net.il

In order to obtain data on the invertebrates inhabiting the forest floor of a carob grove, I sectioned off a 500 sq.m. area populated by carob trees (Ceratonia siliqua), in Tel Aviv. Monthly samples were taken over a 12-month period, composed of 80x80 cm of leaves and soil that had been filtered through nets (4x4 cm to 3x3 mm). The ground was filtered to a depth of 1 cm (6 liter each time).

A total of 295 specimens were caught. Accordingly, 228 specimens covering 16 species were found on the ground surface (leaf layer, average depth of 4.5 cm): 1 species of millipede, 2 land crabs, 2 spiders, 2 centipede and 9 species of insects. The 80X80X1 cm volume of filtered soil produced 67 specimens from a total of 7 species: 1 species of millipede, 2 land crabs, 2 centipedes and 2 species of insects. The leaf layer contained more insects than other species.

In both the leaf layer and the surface layer, six species were found, that is, a sum total of 17 different species of invertebrates were observed.

Animals over 3 mm in size were not found in all seasons of the year in the two layers that were tested, that is, in late summer and early fall, no animals at all were recorded.

By calculating how many individuals were found in the leaf layer each month, we can observe that the greatest number of individuals in both layers is present in late winter to mid-spring. The leaf layer is more responsive following the first rains in early autumn, as exemplified by the number of individuals found. This can probably be attributed to the fact that it takes time for the surface layer to become damp again after the extended period of dryness during the summer.

It was apparent that additional filtering for smaller organisms less than 3x3 mm produced a much longer list of species in both layers. It would be of interest for future research to conduct comparative studies on the forest floor of carob groves in other parts of the country, as well as in forests of other Mediterranean tree species native to this area.