Interisland range expansion of Viola lanaiensis (Violaceae: Malpighiales), an endangered Hawaiian violet

摘要

The monophyletic Hawaiian violet lineage includes five species that are endangered or threatened. A new population of Viola was recently discovered on Helu Peak, West Maui. Individuals in the Helu Peak population appeared morphologically similar to critically imperiled Viola lanaiensis, endemic to the nearby island of Lāna'i. To identify the population on Maui, the Internal Transcribed Spacer sequence from the new population was compared with all other known Hawaiian violets using maximum parsimony. Leaf and floral traits were compared between the Helu Peak population, V. lanaiensis, and V. oahuensis. Maximum parsimony analysis placed the Helu Peak population in an unresolved polytomy with V. lanaiensis and V. oahuensis. Canonical Variates Analysis of leaf variables suggests that the Maui population is morphologically indistinguishable from V. lanaiensis. Floral organ lengths of the new population overlap with previously published values for V. lanaiensis. Due to similarities in morphology and close genetic relationships, we are classifying the Maui population as a new interisland population of V. lanaiensis. On Lāna'i, V. lanaiensis is reduced to an extant population of six individuals. Over 140 individuals are currently distributed on Maui. Despite the increase in the wild population of V. lanaiensis, the species will likely remain listed as endangered. Conservation actions for the species on Lāna'i and Maui will involve seed collection and storage, propagation and outplanting, and habitat protection.