LESSONS IN ECOSYSTEM MANAGEMENT FROM MANAGEMENT OF THREATENED AND PEST LORANTHACEOUS MISTLETOES IN NEW-ZEALAND AND AUSTRALIA

Loranthaceous mistletoes are interesting because of their complex depe ndence on suitable host trees nad avian dispersers and because of thei r patchy distribution at the landscape level. Although their over- and under-abundance in Australia and New Zealand have been widely documen ted, little attention has been given to the need of an ecosystem appro ach to their management. Although the current status of mistletoes is very different in Australia and New Zealand, some of the causal factor s and the long-term effects of changes in mistletoe abundance are simi lar in the two countries. We suggest that mistletoe abundance in pre-E uropean landscapes was dependent on a series of evolutionary and envir onmental filters relating to host specificity, pollination, dispersal, infection, environmental habitat quality, predation, and disturbance. European settlement modified there filters in a number of ways, resul ting in either increases or decreases in mistletoe abundance. The thre e broad groups of changes that have occurred with European settlement involve fragmentation, predation, and altered disturbance regimes. Alt hough managers have usually addressed mistletoe over- or under-abundan ce with short-term solutions (e.g., pruning infected trees), we sugges t that management must address the underlying causes of the problems i nvolving mistletoes. This requires an ecosystem approach to management that addresses both the direct and indirect causes of the current sta tus of mistletoes.