Abstract:
Four grids, each 3,42 ha (4 morgen) in size, were live
trapped from April 1967 through May 1969 in two soil and vegetation
types (black turf~ Acacia nigrescens community, and
brown reddish soil: Acacia tortilis community) at Pongola,
northern Zululand, to determine the effect of dieldrin coverspraying,
at a dosage of 87,4 g/hectare (2,64 oz/morgen), on
rodents. Low population numbers before and especially at the
time of spraying made clear-cut conclusions impossible to
reach. Rodent populations (mainly Praomys (Mastomys) natalensis,
Saccostomus campestris, and Lemniscomys griselda) were
apparently not adversely effected, although L. griselda numbers
showed a decline which was not in correspondence with
that on the control area. This might be ascribed to dieldrin
spraying. Relatively higher numbers of s. campestris and
L. griselda were observed during periods of lower P.( M.) ~talensis
numbers. Decreases in P.( Me) natalensis populations
coincided with times of food scarcity. Praomys (Mastomys)
natalensis are thus found in association with other rodents
when abundant food is available, but seems to give way when
competition due to food scarcity occurs.
Reproductive data obtained from the study were too meagre
to allow any conclusions concerning the effect of spraying
thereon. The method involving the calculation of maximum distance
between captures was used to express movement patterns of
the species studied.
Populat~on structure is express~d in terms of sex
ratios, and frequency per mass class for each season.
The size of animals was investigated by measuring
total length, tail length, and head and body length.
Behavioural features of the species captured were also noted.
