Aegilops triuncialis (Barbed Goatgrass) is an annual grass that was introduced from its native range in Eurasia, into California in 1924. In the past 30 years this species has become a problematic invasive in California. The invasive species is a federal and state-listed noxious weed due to its poor palatability for livestock, and is a recognized threat to western rangelands and native habitats. It is especially worrisome because of its ability to invade serpentine soil communities, which are very high in endemism and relatively free of exotic invasives. Aegilops triuncialis has been intensively studied because of its close relationship with cultivated wheat, Triticum aestivum, allowing the infrastructure and resources of wheat genomics to be applied to genetic questions in goatgrass invasions. We are studying the post-introduction evolutionary dynamics of this invasive species as well as the genetics of range expansion in severely bottlenecked populations of A. triuncialis in multiple sites in California. We have proposed that: 

1) Maternal environmental effects (cross-generational phenotypic plasticity) are an important type of adaptive plasticity facilitating the persistence and initial spread of this invasive species. 

2) Mutation accumulation in quantitative traits is an important source of genetic variation for adaptive change in selfing plant invaders that experience extreme bottlenecks. 

Maternal environmental effects were studied in three serpentine sites where subpopulations were grown in “edge” and “core” habitats in order to answer questions relating to the interaction between maternal and offspring genotypes and environments. 

To study the accumulation of mutation in A. triuncialis, we first identified populations founded by a single homozygous haplotype in order to test the hypothesis that populations derived from a single introduction event can be viewed as replicates within a mutation accumulation experiment. Because of the extreme bottlenecks that may often occur in biological invasions, this could provide a unique opportunity to examine how the basic evolutionary process of mutation can contribute to invasiveness.