120
0. R. POTTS A N D 0. P. VICKERMAN
removal of the climax vegetation some 3000 years ago, except by
grazing, although the site had not been grazed for 11 years. Dominants
were Poterium, Plantago, Leontodon together with many bryophytes
and some Viburnum scrub. The mound ant Lmiw favus (F.) was
present, and Orthoptera and Lepidoptera were well represented.
(2) Modified Downland-similar to (1) except that the grass was cut
in 1968, the soil was richer and some Holcus was present. There was a
bramble (Rubw fructicosw L.) “hedge” nearby.
(3) Winter barley.
(4) Spring barley.
Details of sites (3) and (4) are given below:
Summer 1968, spring barley var. Vada treated with herbicides
August 1968, straw and stubble flora completely burnt after desiccation
witi paraquat
SITE (3)
15 Sept. Ploughed
25 Oct.
Cultivated and drilled
1969
var. Sent&
25 March Fertilizer applied
17 April Sprayed with CMPP
8 April Rolled
and copper.
Stellaria media
controlled
Traps placed in weedfree crops
9 June
SITE (4)
20 Nov. Ploughed
1969
4 March Disc harrowed
20 March Ploughed again
30 March Disced and harrowed
2 April Drilled var. Vada
8 April Rolled
12 May Sprayed with TBA,
CMPP, MCPA Dicamba
and copper at usual
rates.
Traps placed in weedfree crops
9 June
Both sites were situated in the same large (100 ha) field and the
traps situated 200 m in from the hedge.
The fauna at all four sites was taken from ten 6.5 cm diameter
pitfall traps at 2 m intervals along a line grid. The traps contained a
mixture of detergent and water. The contents were emptied every five
days during June.
The index of faunal diversity (a) used was that of Williams (1944,
1945). It was impracticable to identify all individuals t o the species
level, especially the Hymenoptera-Parasitica which were only reduced
to family level. However, it has been shown by Lewis (1969) that the
use of a is still justifiable in such situations.
Slightly more arthropod taxa were recorded from the richer downland at site (2) than from the downland at site (I). The spring barley,
0. R. POTTS A N D 0. P. VICKERMAN
removal of the climax vegetation some 3000 years ago, except by
grazing, although the site had not been grazed for 11 years. Dominants
were Poterium, Plantago, Leontodon together with many bryophytes
and some Viburnum scrub. The mound ant Lmiw favus (F.) was
present, and Orthoptera and Lepidoptera were well represented.
(2) Modified Downland-similar to (1) except that the grass was cut
in 1968, the soil was richer and some Holcus was present. There was a
bramble (Rubw fructicosw L.) “hedge” nearby.
(3) Winter barley.
(4) Spring barley.
Details of sites (3) and (4) are given below:
Summer 1968, spring barley var. Vada treated with herbicides
August 1968, straw and stubble flora completely burnt after desiccation
witi paraquat
SITE (3)
15 Sept. Ploughed
25 Oct.
Cultivated and drilled
1969
var. Sent&
25 March Fertilizer applied
17 April Sprayed with CMPP
8 April Rolled
and copper.
Stellaria media
controlled
Traps placed in weedfree crops
9 June
SITE (4)
20 Nov. Ploughed
1969
4 March Disc harrowed
20 March Ploughed again
30 March Disced and harrowed
2 April Drilled var. Vada
8 April Rolled
12 May Sprayed with TBA,
CMPP, MCPA Dicamba
and copper at usual
rates.
Traps placed in weedfree crops
9 June
Both sites were situated in the same large (100 ha) field and the
traps situated 200 m in from the hedge.
The fauna at all four sites was taken from ten 6.5 cm diameter
pitfall traps at 2 m intervals along a line grid. The traps contained a
mixture of detergent and water. The contents were emptied every five
days during June.
The index of faunal diversity (a) used was that of Williams (1944,
1945). It was impracticable to identify all individuals t o the species
level, especially the Hymenoptera-Parasitica which were only reduced
to family level. However, it has been shown by Lewis (1969) that the
use of a is still justifiable in such situations.
Slightly more arthropod taxa were recorded from the richer downland at site (2) than from the downland at site (I). The spring barley,