Discussion
Our experimental evaluation of the multiple resource limitation model
confirmed that the reproductive allocation patterns of species strongly
depend on both light limitation (dominant removal) and the level of
belowground water resources. This observation provides empirical support
for the evolutionary importance of interactions between above- and
belowground resource levels for variation in reproductive investment in
clonal plants (Herben et al. 2015; Tonnabel et al. 2017). The
heritability and potential for further evolution of the proportion of
flowering ramets in clonal plants has previously been supported (Kleunen
et al. 2002; De Kort et al. 2020). The adaptive role of plasticity in
reproductive allocation under stress conditions has also been
demonstrated (Santos-del-Blanco et al. 2013). This contrasts with the
non-adaptive null hypothesis for resource matching in flowering. The
resource matching assumes a constant allocation of a proportional
fraction of annual resources to both seed reproduction and vegetative
growth, and that species reproductive allocation does not change with
resource level (Kelly & Sork 2002; Pearse et al. 2016; Bogdziewicz et
al. 2020). Consistent with our expectations of species reproductive
trade-offs in the herbaceous community, we found that the competitively
dominant species require more belowground resources for seed
reproduction, while competitively weaker subordinate species can
reproduce at lower resource levels (Fig. 1a).