Returning mistletoe to an urban forest: a restoration success story

Abstract

Mistletoes have a fraught public relations history. Vilified as toxic tree-killing weeds, they have long been targeted for removal by arborists and forest managers concerned with tree health. Research on mistletoe ecology has revealed their positive influence on diversity and community structure via complex networks of interactions. In areas where mistletoe has traditionally been removed, managers are now asking whether these parasitic plants can return on their own or whether they should be reintroduced. To evaluate the practicalities of mistletoe restoration, we inoculated 28 London plane trees Platanus × acerfolia (Aiton) Willd. in inner Melbourne with creeping mistletoe Muellerina eucalyptoides (DC.) Barlow, a locally rare species. Branch dimensions and aspect had no discernible effect on germination or seedling emergence, but trees where access to possums (Trichosurus vulpecula (Kerr, 1792) and Pseudocheirus peregrinus (Boddaert, 1785)) was restricted were 30% more likely to host seedlings. Five years after inoculation, seven mistletoes successfully established on five trees, with two mistletoes bearing fruit. Communications with residents and city users elicited positive feedback, catalysing four additional inoculation trials in urban and forest settings elsewhere. In addition to representing a cost-effective means of enhancing habitat values, mistletoe restoration is useful for addressing open questions about mistletoe ecology and educating the community about the functional roles these parasitic plants play.