Back during the winter of 2009-2010 I sowed restoration plots that consisted of twelve grassland species at three sites in three states. At each site I sowed the same species and the same weights of live seeds for each species, but I manipulated seed source at the community level. The general design of the experiment is shown in Fig. 1 below.
The purpose of the experiment is to determine whether seed source effects community and ecosystem level properties. We know that provenance affects the performance and expression of traits for individual species at single sites, and these responses are idiosyncratic, meaning that sometimes local sources perform best and sometimes other sources perform best at the species level. What we know less about is whether or not we see source differences for species when they are grown in a more realistic community setting, whether source effects are consistent across sites, and whether effects scale to community and ecosystem level properties. Also, there is a mixed treatment, which should give insights into whether variation within single sources is limiting.
In this experiment, terrible drought in Oklahoma led to very poor establishment in the first year (2010) and near complete die-off in 2011, so I exclude that site below and show some responses of different sources at the Nebraska and Kansas sites. I focus on data from September harvests of aboveground biomass for all sown species combined and non-seeded species combined.
I will say without showing any evidence that the individual species differ from one-another in their patterns. Together, these have led to source effects on both seeded and non-seeded productivity (Figure 2). But I thought the pattern in Figure 3 was especially cool, and I’m looking forward to adding to it next month