Time Segment Analysis of Permanent Quadrat Data—Changes in Hieracium Cover in the Waimakariri in 35 Years

A technique for inferring long term time trends in vegetation from permanent quadrat data using the different patterns in the scattergram of the mean and rates of change of attributes, e.g., cover, from individual quadrats over short periods is described. The technique is illustrated using point intercept cover data for Hieracium species from permanent transects in the Waimakariri measured at intervals over 35 years. There was an exponential increase of 8.6% of Hieracium spp. percentage cover once they appeared in a quadrat up to about 15% cover. The indications were that Hieracium may stabilize on these sites at an upper mean level of c. 34% cover.