An invasive grass species has both local and broad-scale impacts on diversity: Potential mechanisms and implications

Questions

The impact of invasive plant species on native diversity varies with spatial scale, with some invaders leading to broad-scale diversity declines and others only local declines. These discrepancies may reflect the invaders capacity to reduce niche opportunities across spatial scales which can be associated with their functional traits. We investigated impact-scale relationships and trait-based mechanisms, in areas invaded by the exotic perennial grass species, Bothriochloa pertusa. We examine root traits specifically, as belowground competition was considered particularly important to the success of this species.

Location

Grassy ‘ironbark’ woodlands of eastern Queensland, Australia

Methods

We examined plots with varying degrees of invasion by B. pertusa, at multiple spatial scales (up to 1000 m2) and analysed changes to the species area relationships (SARs) with increasing invader cover. Changes to SARs were assessed in relation to the invaders effect on rare (lo...