Abstract Detail

Molecular Ecology

Investigating the genetic basis of the cheatgrass invasion in North America.

Predicting the trajectory of biological invasions under global warming is a major challenge in eco-evolutionary research. The annual grass Bromus tectorum (cheatgrass) is native to Eurasia and northern Africa and a dominant invasive in shrubland ecosystems of western north America. Cheatgrass has locally adapted to a wide range of environments in both the native and invaded range. However, it is unclear if preadapted genotypes colonized distinct environments in north America, or if there has been rapid local adaptation following admixture or de novo mutation. We aimed to identify geographic patterns generated by genetic and environmental variation in native and invasive populations. Through a network of professional and citizen scientists around the world, we obtained >500 collections and resequenced ~200 genotypes representing naturally inbred populations from the native and invaded range. We grew these genotypes under controlled conditions, and measured performance, flowering time, and multiple vegetative and reproductive traits. Flowering time showed the highest broad sense heritability, allowing to dissect its genetic basis in upcoming analyses. A PCA of phenotypes described life history variation where earlier flowering is associated with lower vegetative investment (fewer tillers and leaves) and higher fecundity (greater seed mass and spike length). We found parallel clines in flowering time across temperature gradients in both native and invasive populations. On average, native genotypes flowered earlier than invasive ones, likely because the native populations are from on average warmer sites than invaded populations. Our study provides a strong foundation for understanding the genetic basis of an unfolding invasion.

1 - Pennsylvania State University, Biology, 405D Huck Life Sciences Bldg., University Park, PA, 16802, USA
2 - 408 Life Science Building, University Park, PA, 16802, United States

Keywords:
invasive species
adaptation
life history.

Presentation Type: Oral Paper
Number: ME1001
Abstract ID:899
Candidate for Awards:None