UC Davis

“Growth-reproduction strategies of non-native grasses along a precipitation gradient”

ABSTRACT

Globally, grasslands are economically, ecologically, and culturally important. In California, grasslands are dominated by annual native and non-native species. This can lead to intense spread of highly invasive species that are economically and ecologically costly. The spread of native, non-native, and invasive species is linked to the allocation of resources to propagule production versus growth, stress tolerance and defense mechanisms. Here I ask, how do California grassland plants trade-off their limited resources between growth and reproduction and how does this vary across California’s precipitation gradient? I constructed a common garden experiment in Davis, California with five representative grassland communities from along California’s cis-montane grassland precipitation gradient (300 mm – 1140 mm mean annual precipitation). In spring 2023, I measured twelve species from each community for growth and reproductive investment. Preliminarily, I found that species identity was a significant factor in the allometric relationship between vegetative and reproductive biomass (p less than 0.005). Most notably, I found that many species found in multiple communities had significantly different growth-reproductive relationships depending on their home site precipitation regime, lending insight into the positive and negative consequences of unintended and intended assisted migration in a restoration context.