The role of native birds in weed invasion, species decline, revegetation and reinvasion: consequences for lantana management.

The threat posed by Lantana camara L. ( lantana) to native biodiversity has recently been assessed nationally. Part of this assessment identified 113 native bird species associated with lantana infestations, with 24 directly threatened; 68 positively influenced (or benefited) by lantana invasions; and another 21 species threatened but also partially benefiting (e.g. from additional food resources) from lantana invasions. Of the bird species that benefit from lantana, 28 are reported to consume lantana fruits as well as the fruits and seeds of a range of native plants, some of which are also threatened by lantana. Information on the fruits and seeds consumed by these 28 bird species can be used to determine the role of birds in native plant species declines, revegetation, and invasion processes. For example, 202 native plant species that produce fruits and seeds which are consumed by these birds are also threatened by lantana. Thus these birds may have indirectly contributed to native plant species decline through the dispersal of lantana into native communities. In addition, such actions could hamper restoration efforts with the birds continuing to disperse lantana as well as another 36 weed species, which have been observed to invade following the control of lantana. Such information is critical for developing longterm weed management strategies for biodiversity conservation, as well as understanding the role and implications of bird dispersal. As native birds play a role in dispersing both native and alien plants, it will be important to encourage native plant recovery, while controlling weeds that will continue to invade over the long-term.