Nanism and ephemerism as reasons for a hidden abundance in vernal pool plants: The example of Lepuropetalon spathulatum in Chile

Abstract

AbstractMinute size (nanism) and short live cycle (ephemerism) are characteristic features of many plants living in seasonal wetlands in Mediterranean biomes. Lepuropetalon (Celastraceae) is a monotypic genus with an antitropical distribution (disjunct in temperate regions of both Americas). L. spathulatum is the smallest vascular plant of Chile, not recorded in herbaria for decades. Its distribution, ecology and phytosociology were studied based on herbarium vouchers and field observations. L. spathulatum occurs in the fringes of vernal pools, on oligotrophic sandy soils and in grazed Acacia caven pseudo‐savannas. Its distribution is linked to the Mediterranean and Submediterranean bioclimates. Associated species are other dwarfish annuals, many of them originating from the Western Palearctic subkingdom and characteristic for the class Isoëto‐Nanojuncetea. Other floristic elements are Chilean endemics and species with a disjunction to California (character species of the Nanojuncetea australis). L. spathulatum is not a rare plant in Chile, but is often overlooked because of its dwarfish and ephemeral habit. Although most populations occurred in secondary habitats and the species can tolerate disturbance, intensification of agriculture, forest plantations and modification of the hydrological conditions may threaten the species in the long term. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)