Indicator Species for the Interpretation of Vegetation Condition in the St Bathans Area, Central Otago, New Zealand

Active adaptive management is what land managers do every day by implementing a strategy, observing or measuring the outcomes and adapting their management accordingly. Monitoring, is therefore an integral part of the adaptive management process. It provides not only a basis for decision making, but also for maximising the development of new knowledge (Gibson, Allen and Bosch, 1995). In monitoring programmes, where the intention is not a detailed vegetation study but identification of the major trends and evaluation of the success of adaptive management strategies, the technique needs to be fast and sensitive to relevant vegetation change. Many methods calculate an index of vegetation condition by using all the species at a recorded site (e.g., Dyksterhuis, 1949; Foran, Tainton and Booysen, 1978; Vorster, 1982). Generally, however, the abundance of only a few species is strongly correlated with grazing, and these would therefore be indicators of a particular condition (Hurt, Hardy and Tainton, 1993; Bosch and Janse van Rensburg, 1987). Monitoring of species that are not responsive to grazing could decrease or distort the sensitivity of the calculated condition index as these species will contribute noise to the data (Hurt et al., 1993). The exclusive use of indicator species can simplify monitoring, especially in community-based monitoring programmes, where R.S. GIBSON and O.J.H. BOSCH