The association between plant breeding systems and the abiotic environment in a Hawaiian endemic plant genus, Schiedea

Background/Question/Methods

The evolution of plant mating systems has been a deeply studied subject among plant biologist because of the diversity in the types of mating systems and independent evolution in many genera. Understanding the connection between environmental gradients and species trait distributions may contribute valuable evidence to comprehend species persistence in particular locations. In addition to geographic location, specific characteristics of plant species can act in concert with habitat loss to exacerbate extinction risks. For example, in a species with a dioecious (separate sexes) breeding system, resource limitation can affect sex ratios, thus influencing reproductive ability especially in small populations (Ashman 1999). In this project, I model the distribution of breeding systems in the Hawaiian endemic genus Schiedea using a species distribution modeling approach.

Results/Conclusions

Breeding systems were grouped into 4 categories (hermaphroditic, gynodioecious, subdioecious, and dioecious). Predictor variables used were climatic, topographic, and edaphic factors. The breeding system distribution models were then compared to assess overlap and associaton to predictors. Results indicate that moisture regime, thermal tolerances, and slope associated factors play a role in the distribution of breeding system. Results from this project shed light on the habitat conditions that have led to the wide variety of breeding systems in Schiedea and possibly other genera on the Hawaiian archipelago. With the concerns raised by global climate change, such research may answer questions on whether breeding systems within Schiedea will continue the shift toward more dioecy and if species will persist in new climate envelopes.