Fauna stratification on the Forest Floor of Eucalyptus Grove

Zvi Sever

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

SEV@NETVISION.NET.IL

(Presented: Zoological Society of Israel's conference 2012)

In order to obtain data on the invertebrates inhabiting the forest floor of a eucalyptus

grove, I sectioned off a 1000 sq.m. populated by Red River Gum trees (Eucalyptus

camaldulensis) in Hakfar Hayarok. Monthly samples were taken over a ten-month

period, composed of three 20x20 cm of leaves and soil that had been filtered through

nets (4x4 cm to 3x3 mm). The ground was filtered to a depth of 20 cm, from four

layers: 0-5, 5-10, 10-15, 15-20 cm deep. Pitfall traps were placed twice monthly.

A total of 201 specimens were caught. Accordingly, 33 species were found on the

ground surface: 2 land crabs, 3 centipedes, 11 spiders, and 17 species of insects. The

20X20X20 cm volume of filtered soil produced 38 species: 1 worm, 2 land crabs, 2

centipedes,3 snails, 5 spiders, and 25 species of insects. The layers of leaves and soil

contained more insects than other species.

A total of 130 specimens were extracted from the ground layers. Examining the

number of organisms, there is similarity in the distribution pattern between the first

layer (5 cm depth) and the second layer (5 - 10 cm). Still it was noted that more

individuals were present in the first layer.

In the third layer (10 - 15 cm), invertebrates were seen in the spring and early

summer, although quantitatively less there than in the upper layers. (3 specimens per

sample as compared to between 5 and 12 specimens, respectively).

The model of the fourth layer (15 - 20 cm) is similar to the one above it, though larger

quantities of organisms were observed in the autumn. Only here organisms were

found during the autumn, usually the larvae of insects.

In late summer no organisms over the size of 3 mm were found in all the soil layers.

It would be worthy to carry out further investigations by filtering the forest floor of

other species of eucalyptus.