Variation in Germination Traits Inform Conservation Planning of Hawaiʻi's Foundational ʻŌhiʻa Trees

Abstract

ABSTRACT Climate can play a critical role in seed development and germination. Linking seed germination information with environmental variables and provenance may be important in understanding plant community structure and response to climate change, which can help guide conservation planning. Native Hawaiian Metrosideros (Myrtaceae; ʻŌhiʻa) is a hyperdiverse species complex that dominates Hawaiʻi's wet and mesic forests and serves as the most bioculturally important native plant in Hawaiʻi. In response to Rapid ʻŌhiʻa Death, a major threat to native forests caused by introduced fungal pathogens, seed collections of ʻŌhiʻa across the state have increased. We used initial seed germination data from recent collections stored in the National Tropical Botanical Garden’s Seed Bank to explore if seed germinability is correlated with seed zones and environmental variables. Linear models of the proportion of seed germinated, seed zones, and environmental data revealed that only seed zones were significantly correlated with the proportion germinated. Seed germination was lower for the “Nā Pali Valleys” than the “Windward Ranges.” Generalized provisional seed zones are a helpful tool for conservation collecting and restoration planning. Germination data routinely collected for seed bank collections provide an easily accessible source of preliminary information for these purposes.