Landscape context and plant invasion

Invasive plant range expansion takes place at large spatial scales, often encompassing many types of land cover, yet the effect of landscape context on seed dispersal remains largely unknown.  Many studies have reported a positive correlation between invasive plant abundance and human land use and increased seed dispersal in these landscapes may be responsible for this correlation.  I tested the hypothesis that increased rates of seed dispersal by fig-eating birds, which are more common in urban habitats, result in an increase in invasive strangler fig abundance in landscapes dominated by human land use.  I used data on strangler fig abundance to parameterize spatially-explicit models that predicted juvenile fig abundance from distance to adult fig seed sources and fig-eating bird habitat quality.  The best model for invasive figs suggested that landscape effects on invasive fig abundance are mediated by seed-dispersing birds.  Understanding seed dispersal as a demographic mechanism of plant invasion may lead to better management techniques, in this case prioritizing the removal of adult fig trees in sites with high human land use.

This research has been published as:

Caughlin T.T., Wheeler J.H., Jankowski J.J., Lichstein J.W. 2012. Urbanized landscapes increase invasive but not native strangler fig abundance. Ecologydoi: