The double allopolyploidSphagnum×falcatulum(Sphagnaceae) in Tierra del Fuego, a Holantarctic perspective

Abstract

A Holantarctic species, the inter-subgeneric allopolyploid Sphagnum 6falcatulum s.l. is a cryptic species complex composed of allodiploid and allotriploid cytotypes. The allotriploid plants are double allopolyploids (one of just two reported for bryophytes), with the allodiploid cytotype being one parent. Using a combination of microsatellites, nucleotide sequences, and morphological characters, allotriploid S. 6falcatulum is shown to be the most widespread Sphagnum species in the Holantarctic, with genetically documented populations in South America (Tierra del Fuego), New Zealand (South Island), and Australia (Macquarie Island, Tasmania). It is further concluded that six Sphagnum species described from the Tierra del Fuego Archipelago (TDF) of South America and a seventh described from South Island, New Zealand are synonymous with the allotriploid cytotype of S. 6falcatulum. The synonymized species include five named by Heikki Roivainen in 1937, S. 6ehyalinum, and S. subditivum. Allotriploid S. 6falcatulum is the predominant, perhaps the only, subgenus Cuspidata species present in TDF and immediate vicinity. The combination of low genetic diversity and an apparent absence of sexual reproduction indicate that the TDF population of the dioicous allotriploid S. 6falcatulum was likely founded by one or a limited number of individuals. The same is apparently the case for Macquarie I. and Tasmanian populations of allotriploid S. 6falcatulum. Several lines of evidence, including high genetic diversity, frequent sporophyte production, and the occurrence of the allodiploid parent, suggest that allotriploid S. 6falcatulum likely evolved in New Zealand.

Local adaptations in bryophytes revisited: the genetic structure of the calcium‐tolerant peatmoss Sphagnum warnstorfii along geographic and pH gradients

“…Low levels or even a lack of genetic differentiation between plants on different continents occur in other bryophytes, including the Sphagnum species (see, e.g., Stenøien and S astad 1999;Thingsgaard 2001;Stenøien et al 2011). Some studies have shown a significant, yet weak, genetic differentiation between the intercontinental populations of peatmoss species (Stenøien and S astad 1999;Sz€ ov enyi et al 2008;Karlin et al 2013). Our results suggest that the North Atlantic Ocean is not an insurmountable barrier for gene flow in a S. warnstorfii metapopulation.…”

“…; Karlin et al. ). Our results suggest that the North Atlantic Ocean is not an insurmountable barrier for gene flow in a S. warnstorfii metapopulation.…”

“…The founder effect, resulting from a dispersal at a large distance with the consequent inbreeding and high geographic isolation, could then lead to losses of heterozygosity in some isolated areas (Karlin et al. , ).…”

“…Nevertheless, there are certain dispersal limitations at the coarsest scales (Sz€ ov enyi et al 2008), at least for some species (Sn€ all et al 2004). The founder effect, resulting from a dispersal at a large distance with the consequent inbreeding and high geographic isolation, could then lead to losses of heterozygosity in some isolated areas (Karlin et al 2012(Karlin et al , 2013.…”

Nuevo registro de Sphagnum falcatulum Besch (Sphagnaceae) en Isla Navarino, Reserva de la Biósfera Cabo de Hornos

“…Aunque su presencia se ha documentado para otros sectores de la ecorregión subantártica de Magallanes (Díaz et al 2005), S. falcatulum está pobremente registrado en la Isla Navarino, detectado el año 2013 en la zona de Puerto Toro (al Este) a un costado de un camino vehicular e ingresada a la colección del New York Botanical Garden (http://sweetgum.nybg.org/ science/vh/). De acuerdo con Karlin et al (2013), S. falcatulum es la especie de Sphagnum más ampliamente distribuida en el Holoantártico (que incluye el continente Antártico, la Tierra del Fuego, la ecorregión subantártica de Magallanes, Nueva Zelanda, y las islas del océano Antártico al sur de los 40º latitud). La singularidad del hábitat donde registramos a S. falcatulum -ilustrado en las fotografías de la Figs.…”