Remote sensing of invasive plants: incorporating functional traits into the picture

Invasive plant species spread presents a challenge, requiring better mapping and monitoring for control. Remote sensing (RS) provides an efficient tool to map invasive plants in diverse ecosystems. Yet applications of RS for invasive plant mapping largely rely on spatial and spectral patterns. The use of invasive plant functional traits can improve RS mapping, using ecological insights on processes and functions associated with invasion. We summarize research utilizing plant functional traits in RS mapping of invasive species from the years 2000 to 2014. Based on this review, we summarize plant traits that can be related to spatial and spectral properties, and used to discriminate invasive alien plants from native vegetation. Phenological and structural plant traits have been relatively well exploited via RS for invasion studies. In comparison, there has been limited utilization of physiological traits (with the exception of properties such as nitrogen content). This is an area that merits further research attention, via the linkage of ecophysiological field research with RS.