ECOLOGY IN THE MANAGEMENT OF INDIAN JUJUBE (ZIZIPHUS-MAURITIANA)

Strategies for cont rolling invasive plants in northern Australian eco systems must be designed to use limited resources. This paper examines the potential contribution of ecology to develop management strategie s for Indian jujube, an invasive shrub in northern Australian tropical woodlands. Its fleshy fruits are dispersed by a variety of birds and mammals. Domestic cattle are the major dispersal vector, whose movemen ts can be controlled at critical times to minimize the risk of new inf estations. Containment of Indian jujube must include avoiding cattle m ovement from infested to weed-free paddocks and from infested to weed- free areas. The species has a capacity co sprout following topkill due to fire or mechanical treatment. This means that current options for effectively treating established plants are limited to the application of herbicides and the more expensive mechanical techniques. In single paddocks, concentrating limited resources on large reproductive plant s may be more effective than concentrating on plants spatially periphe ral to an infestation. Ar the property level, the first priority shoul d be to prevent weed-free paddocks from becoming infested, the second should be to minimize increases in lightly infested paddocks, and the third to treat heavily infested paddocks char are major potential sour ces of new infestations. At the regional level, distributional outlier s become important; their control may significantly reduce the length of the front from which local range expansion will occur.