Studies on the moss flora of the Bío-Bío Region of Chile: Part 3

Abstract This is the final report on the moss flora of the Bío-Bío Region (Región VIII) in south-central Chile where collections were made in 2001–2003. Reported in this paper are one species new to South America, four species new to Chile and 16 species new to the Region. With these new additions the total number of taxa in the Bío-Bío Region is 343, corresponding to 331 species and 12 infraspecific taxa. A complete checklist of the mosses for all the provinces in the Region is presented.


Introduction
This is the final paper on the moss flora of the Bío-Bío Region of Chile, reporting the identifications for the specimens collected by R.R. Gilda Bellolio in 2001-2003. Two earlier papers by Ireland et al. (2006Ireland et al. ( , 2010 reported many mosses new for the Region, as well as for all of Chile. In the present paper are reports for one species new for South America, four new for Chile and 16 new for the Bío-Bío Region. All collection numbers are those of the two authors and the identifications were made by R.R. Ireland and Juan Larraín, with the exception of some problematic specimens that were identified by various other bryologists. The original checklist of the mosses by He (1998) reported 190 taxa for the Region which was later updated by Müller (2009a, b) who reported 315 taxa. This number was subsequently increased to 323 taxa by Ireland et al. (2010). The total number of taxa now known for the Bío-Bío Region is 343, which is the current number reported in the present paper.
Since the publication of the first paper of this series on the Bío-Bío moss flora (Ireland et al. 2006), the administrative division of Chile has slightly changed, modifying the map given in the latter reference. In October 2007, two new regions were created after the breakup of the former I and X Regions: Region XV (Arica y Parinacota) became the northernmost region after splitting of the former I Region, whereas Region XIV (Los Ríos) was created to separate the administration of Valdivian area from the rest of the former Los Lagos Region (X Region, see Fig. 1).

Methods
Phytogeographic information, climate and geomorphology for the four provinces (Arauco, Bío-Bío, Concepción, Ñuble) in the Region are all reported in the first paper of this project by Ireland et al. (2006). Voucher specimens of most of the collections are at CONC, MO and US, with many at NY. All numbers listed below correspond to specimens collected by Robert R. Ireland and G. Bellolio, unless otherwise indicated.
For the taxonomy we follow Müller (2009a), with the exception of the genus Bryum for which we followed the segregates outlined in Spence (2014). Segregates of Racomitrium are not recognized as suggested by Larraín et al. (2013). Synonyms are indicated for taxa treated under a different name in Müller (2009a) or on the Internet at www.tropicos.org.
For the biogeographical analysis, we grouped the taxa into seven groups: "Endemic" meaning taxa distributed in Chile, adjacent Argentina, sometimes extending into the Falkland Islands, South Georgia or the Juan Fernández Islands; "Wide Distribution" meaning taxa distributed in several continents or without a clear geographical pattern; "Southern Hemisphere" refers to widely distributed subantarctic species sometimes reaching tropical areas in the Andes or in South East Asia; "Bipolar" meaning taxa distributed in the temperate areas of both hemispheres; "Neotropical" meaning taxa widely distributed in Latin America and the Caribbean, including some species restricted to South America; "Gondwanic" referring to taxa distributed in southern South America and New Zealand and Australia; and "Neotropical + African" meaning taxa distributed both in the tropical and/or subtropical areas of both Latin America and Africa.   (Müller 2009a). This record represents a northern extension of the distribution of this taxon.

Biogeographical analyses of the Bío-Bío mosses
From the biogeographical analyses of the taxa found in the Bío-Bío Region, 39.65% of the taxa are endemic to southern South America and adjacent areas, 24.19% of the taxa are bipolar, 13.7% are Southern Hemispheric taxa, 10.2% correspond to Neotropical taxa, 4.95% are Gondwanic taxa, and only 2.91% of the taxa are shared between southern South America, the Neotropics and Africa (Fig. 2).
In terms of the distribution of mosses within the Bío-Bío Region, we have seen that the most diverse province is Ñuble with 226 taxa, followed by Bío-Bío Province (210), Concepción Province (200), and Arauco Province (197). These numbers may change with the more collecting still needed in all the four provinces.

Discussion
After the examination of more than 6,000 collections from Bío-Bío Region, a total of 343 moss taxa are reported in this paper. This number represents a major increase from the 190 taxa reported by He (1998) in the last checklist done before the beginning of this project. Several taxa had to be reevaluated, several names had to be changed and updated due to recent revisionary studies made by colleagues worldwide, and some taxa previously reported for the region had to be excluded from the Bío-Bío moss flora. A number of our colleagues identified difficult groups, like the Pottiaceae (María Jesús Cano, Mayte Gallego, Juan Jiménez, Richard Zander), Fissidens (Ron Pursell †), Bryaceae (John Spence), Dicranaceae (J.-P. Frahm †), and Bartramia, Sematophyllum (Bruce Allen).
As it has been noted elsewhere (Seki 1974, Villagrán et al. 2003, Larraín 2005, 2016, the dominating biogeographical component in any central or southern Chile region corresponds to the endemic element, reaching almost the 40% of taxa for the mosses of the Bío-Bío region. The second most represented element is the widely distributed species, that includes several recently introduced taxa or species mostly associated with human disturbances. As it happens in other regions of Chile with the mosses, it is interesting that the Southern Hemisphere plus the Gondwanic elements sum up almost twice the number of taxa that shows a southern South America-Neotropical distribution. Finally, there is a small number of species (n=10) shared between southern South America and the African continent.
Three taxa are still troublesome for us but they have been included in the list. One of these is Andreaea rupestris, a species that has been excluded from the Southern Hemisphere by both Vitt (1980) and Murray (2006). The latter authors suggest that the records reported as A. rupestris from the Southern Hemisphere might correspond to Andreaea mutabilis Hook.f. & Wilson or some other taxon with ecostate leaves. Another doubtful taxon is Plagiothecium denticulatum, reported for the first time for Chile by Mitten (1869), as P. donnianum (Sm.) Mitt. from Cape Horn, and subsequently reported several times by other authors (Müller 2009a). This taxon is not even mentioned in the monograph of Plagiotheciaceae for the Flora Neotropica project (Buck & Ireland 1989), and presently it is considered to be a boreal taxon. The third problematic taxon is Thamniopsis incurva, a widespread Neotropical species whose type was apparently collected in Chile by Chamisso (judging from the label of the type), but it has never been found again in Chile. It is possible that the original specimen of Chamisso was mislabeled and collected somewhere else along the South American coast.