Wood-rat (Rattus tiomanicus Miller) population build-up in a cocoa-coconut plantation after field-poisoning

K. A. Kamarudin, C. H. Lce and J. Abd. Munir

Abstract

The build-up of the Malaysian wood-rat populations in a cocoa-coconut planration after field poisoning was studied. The rat populations were reduced to some low numbers by poison-baiting and monitored by multiple recapture technique thereafter. The populations recoveted rapidly and reached peak levels after 6 and 9 months. A target population (138 animals) that was greatly reduced to 18 rats recoveted to about 88.4% (124 ras) of its original abundance. However,a larger nember that was allowed to survive (38 rats), apparently had a similar rate of recovery, with the population pcaking at 79.5% (90 rats) of its original density. Recruiment into the depopulated arcas was mostly via immigration. The number of rats in the control plots ranged from 112 to 161 animals during those periods. The proportion of recaptures (marked animals), population sizes and survival rates were higher in the control than baited plots (p< 0.01, p< 0.01 and p< 0.05 re.spectively). However, the dilution rate (proportion of new members in the population) between control and baited-plots was not significantly different More males (p> 0.01) contributed to the rat population recovery in both the baited fields. Higher fluctuations in the rate of poprlation change was noted in the baited fields than in the control plot.

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