The effect of pasture availability on food intake, species selection and grazing behaviour of kangaroos
Short, J. (1986) The effect of pasture availability on food intake, species selection and grazing behaviour of kangaroos. Journal of Applied Ecology, 23 (2). pp. 559-571.
Food intake, grazing behaviour and diet of red (Macropus rufus) and western grey (M. fuliginosus) kangaroos were monitored as they progressively depleted an arid zone pasture from 1000-1200 kg ha-1 to an ungrazable residue. Red kangaroos reduced the pasture to a residue of <20 kg ha-1 of halophytic chenopod subshrubs, but grey kangaroos were unable to reduce it below 180 kg ha-1; the residue consisted mainly of chenopods and the lily Bulbinopsis semibarbata. Both species preferred grasses and forbs over chenopods and lily. Red kangaroos harvested grasses, forbs and B. semibarbata at a significantly faster rate. Red kangaroos responded to declining plant biomass and food intake by increasing grazing time by 0.5 h day-1 for each 100 kg ha-1 decrease in available vegetation. The grazing time of grey kangaroos was higher than that of reds from the start of the trial (13.8 v. 10.8 h day-1 at 800 kg ha-1), and less reactive to changes in pasture biomass. Females grazed for longer than males (14.6 v 10.0 h day-1 at 800 kg ha-1). Grazing activity of both species peaked between dusk and dawn with animals spending >60% of their time grazing during this period. The biting rate of kangaroos while harvesting and chewing food did not differ between species, averaging 56 bites min-1. Red kangaroos were significantly more mobile while feeding, taking more steps per minute and fewer bites per step.
|Publication Type:||Journal Article|
|Publisher:||Blackwell Publishing Inc.|
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