Kanakaleonui Bird Corridor Montane Plants 2016

Montane plant communities throughout the world have responded to changes in precipitation and temperature regimes by shifting both margins and core distributional ranges upward in elevation. Continued warmer, drier climate conditions have been documented and are predicted to increase in high-elevation areas in Hawaii, consistent with climate change effects reported in other environments throughout the world. Organisms that cannot disperse or adapt biologically to predicted climate scenarios in situ may decrease in distributional range and abundance over time. Restoration efforts will need to accommodate future climate change and account for the interactive effects of existing invasive species to ensure long-term persistence. We hypothesized that plants from a lower-elevation source would grow and survive at higher rates than plants from a higher-elevation source when grown in common plots along an elevation gradient. We monitored climate conditions at planting sites to identify whether temperature or rainfall influenced survival and growth after 20 weeks. Our findings did not support a single clear effect of seedling origin on plant survival or growth for three native montane species. However, origin influenced survival when controlling for temperature or elevation in two species. There were no clear patterns of growth or survival within or between species, indicating that responses to changing precipitation and temperature regimes varied between montane plant species. Results also suggest that locally sourced seed, despite elevation of mother plants, is important to ensure highest survival at restoration sites. Further experimentation on larger spatial and temporal scales is necessary to determine the empirical responses of species and communities to changing climate in the full context of highly degraded Hawaiian ecosystems.