Defoliation and treading by cattle of reed Phragmites australis.
Abstract
The influence of cattle grazing on marked shoots of P. australis was studied on embanked sandflats of the Lauwerszeepolder, N. Netherlands in 1983-86. Cattle grazed the shoot tips preferring the longest shoots. Bite size was positively correlated with shoot length before biting. By 1 Sep., total reed biomass losses due to cattle activity were 67-98% of aboveground production, with consumption approx. equalling cattle-induced mortality. Grazed primary shoots produced secondary shoots from lateral buds at the shoot base. By Aug., this compensatory growth of secondary shoots in grazed stands had produced a comparable specific leaf area to that produced by primary shoots alone in ungrazed stands. Leaf area index reached 1.6 in ungrazed stands compared with 0.13 and 0.15 in grazed stands in Aug. 1986. The study suggested that with about 70% utilization by 1 Sep. each year, roughly half of which is consumption, the P. australis populations may be in equilibrium with the grazing regime.