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

Abstract

Minute 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)

Vascular plant assemblages of ephemeral wetland vegetation along the Mediterranean-temperate gradient in Chile

“…Species grouped in assemblage 1 also belong to the dwarf annual growth form (nanism sensu Alvarez et al 2012b). They characterize dry annual grassland (Deil et al 2007) and are probably diagnostic species for the alliance Chaetanthero-Vulpion described by Oberdorfer (1960).…”

“…(MoreiraMuñoz & Muñoz-Schick 2007), Hydrocotyle cryptocarpa and Lepuropetalon spathulatum (Alvarez et al 2012b). These diagnostic species are only missing in the plots from the island of Chiloé and from Argentina.…”

“…Additionally, many of these annual species belong to mono-specific genera, such as the Asteraceae Blennosperma, Centipeda, Lasthenia, Micropsis and Microseris (Moreira-Muñoz & Muñoz- Schick 2007, Moreira-Muñoz 2011. The distribution and ecology of vernal pool plant species is poorly known (Alvarez et al , 2012b). An analysis, which species are restricted to the vernal pool habitat and how they are distributed can be a first step to evaluate their vulnerability and the extinction risk and to assess their importance for conservation of plant diversity at the regional, national and even continental scale.…”

A history of discoveries and disappearances of the rare annual plant Lythrum thesioides M.Bieb.: new insights into its ecology and biology

“…The longevity of their seed bank, the scarcity of their habitat and their small size and low frequency in aboveground vegetation, result in a low probability of detection of many of the annual species that predominate in Mediterranean temporary pools, making it difficult to assess their abundance, dynamics and distribution (Aponte et al 2010;Alvarez et al 2012). A complete inventory of the plant communities of a temporary pool thus requires multiple visits during a single year and over several years that experience contrasting hydrological characteristics ).…”

Diversidad Vegetal de Lagunas Temporales en la Estepa Patagónica Chilena Noroccidental

“…En Chile el conocimiento sobre la ecología y distribución geográfica de lagunas temporales es muy escaso y se remite a algunos estudios florísticos y vegetacionales (Bliss et al 1998;Álvarez, 2008;San Martín & Álvarez, 2009), mientras que para otros tipos de biocenosis (por ejemplo, zoocenosis) es prácticamente ausente. Estudios florísticos más detallados se han hecho en lagunas temporales del bioclima mediterráneo (sensu Luebert & Pliscoff, 2006) y en la parte norte del bioclima templado (Bliss et al 1998;Deil et al 2007;Álvarez et al 2012), pero se desconocen estudios hechos al sur del paralelo 44°S. En este trabajo presentamos un catastro de especies de charcos temporales y lagunas semipermanentes (con nivel de agua fluctuante) colectadas durante el verano de 2011 al noreste de Coyhaique (Fig.…”