New Paper in ‘Weed Research’

Propagule pressure alone cannot always overcome biotic resistance: The role of density-dependent establishment in four invasive species

Barney, Ho & Atwater (link)
I am very pleased to announce that we have just had a paper accepted for publication into Weed Research. This paper documents Master’s Student Matt Ho’s research into the role of propagule pressure in invasion. He found that negative density-dependent germination probability causes diminishing returns for species that broadcast a large number of seeds. His results suggest that site conditions and species interactions play an important role in determining invasion probability even when propagule pressure is intense.

Invasion probability increases as the number of seeds (aka propagule size) increases. When germination is density dependent (solid line), invasion probability increases much more gradually than when it is not (dashed line). This means that site conditions play a very important role in determining invasion probability, even when propagule pressure is high.