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Based upon recent checklists, the moss floras of the Mascarenes (Seychelles, Réunion, Mauritius) is compared. The diversity of species varies much amongst the islands and is lowest in the Seychelles (110 species) but highest in Réunion (366 species), whereas Mauritius has 246 species. Interestingly the young volcanic islands Réunion and Mauritius have much higher species numbers as the Seychelles which were part of the Gondwana continent. The richness of mosses in Réunion is due to the higher altitude (3069m), higher rainfall and the better state of conservation (30% of surface consist of intact forest), whereas the maximum altitude of the other islands hardly exceeds 800 m and most forests are destroyed. The moss flora of the islands have only few species on common and are thus almost not related. All islands have only 33 species in common. The Seychelles, which are situated about 1900 km from Réunion and Mauritius, share only 42 viz. 49 species with the latter. Réunion and Mauritius, which are 170 km away, share only 107 species. This indicates that the factor chance played an important role in the colonization of the islands. Insofar the term “Mascarenes” is a geographical but not a floristic one. The Mascarenes were mainly colonized by species from Africa and Madagascar, but also from SE-Asia und the austral region. The main floristic element is African, which is in contrast to the prevailing trade winds and might indicate that the colonization at least of the young volcanic islands happened during a different wind system in the past.
Hot spots are characterized by the occurrence of „hot“ species, rare, endangered, phytogeographically (for example highly disjunct) or ecologically interesting species (for example heavy metal species). The Apuanian Alps (ital. Alpi Apuani) are a place of extraordinary botanical and also bryological interest. Although situated far from the west coast of Europe, many atlantic species are found there, which have isolated occurrences and show up next in Asturias, Macaronesia. Ireland or Scotland. Representative of the oceanic element in the bryoflora are Dumortiera hirsuta, Lejeunea lamacerina, Lophocolea fragrans, Plagiochila exigua, P. bifaria, Saccogyna viticulosa, Harpalejeunea ovata and Marchesinia mackaii, supplemented by ferns such as Trichomanes speciosum and Hymenophyllum tunbrigense (Cortini-Pedrotti et al. 1992). Reasons for the presence of such species in Italy are the extraordinary climatic conditions. Situated directly along the Meditrerranean Sea, the climate is mild and due to depressions in the gulf of Genova, the rain is caught by the mountains resulting in a high precipitation of about 1400 at the foot of the region and more than 3000 mm in the summit region. This does, however, not explain whether these species are relics from the Tertiary or dispersed from the W-coast of Europe after the Pleistocene glaciations.
The Azores are of bryological interest in many respects: They are young volcanic islands with an age between 4 mio and 40.000 years, are situated in an hyperoceanic environment favouring bryophyte growth, the bryophyte flora is composed of European, Neotropical, African and subantarctic elements, there are about as many bryophyte species as flowering plants, the islands have a comparably high rate of endemic species (on single Azorean islands, all Azorean islands or the Macaronesian islands), and the bryophyte flora gives an impression of the bryophyte flora of continental Europe during Tertiary, since many species such as Echinodium spp. or Andoa berthelotiana, known as fossils from the Tertiary of continental Europe, survived here the glaciation periods and got extinct in Europe.
A guide to bryological hotspots in Europe : [Part 2: The Rur Valley, Eifel Mountains, Germany]
(2005)
The Rur valley is situated in the extreme west of Germany in the western part of the Eifel Mountains, close to the Belgian border. The Rur valley harbours several interesting, mainly bryopyhtes. Most of the interesting species are aquatic species. Very obvious is the oceanic element, which is represented by species such as Platyhypnidium lusitanicum, Hyocomium arnoricum, and Isothecium holtii.
Madeira is bryologically insofar very interesting, as it harbours (like the other Macaronesian Islands) relics of the bryoflora of the Tertiary of continental Europe. Originated in the Tertiary at various times, these volcanic islands were mainly colonized from Europe. Whereas many species got extinct in Europe during the glaciations of the Quaternary, these elements were able to survive in these islands. So we are faced there with an ancient bryoflora, especially in the laurel forests, amongst other phytogeographic elements, mainly mediterranean species.
An updated list of the mosses of the Inner Seychelles is given based on the previous literature and collections of the first author in 2008. It includes data on the frequency of species as well as distributional data for the individual islands. The moss flora of the islands is characterized. Campylopus brevirameus Dixon is regarded as synonym of C. julaceus ssp. arbogastii (Renauld & Cardot) J.-P.Frahm. Brachymenium dicranoides, Bryum alpinum, Campylopus flaccidus, C. flexuosus, Ectropothecium brachycladulum, E. chenagonii and E. perrotii are reported as new to the Seychelles. Garckea flexuosa, Syrrhopodon involutus and S. prolifer are reported as new to La Digue, Bryum leptospeiron, Brachymenium exile and Calymperes afzelii as new to Praslin.
Field observations of mixed tufts demonstrate that Hpynum cupressiforme s.str. (excl. imponens, jutlandicum, andoi etc.) consists of several different genotypes which are no modifications. Within a study of herbarium material, the specimens were sorted into different phenotypes, for which names were applied from the literature. Within Hypnum cupressiforme, an expression with straight leaves (var. brevisetum Schimp.) was distinguished as well three with hamate leaves (var. uncinulatum Boul., var. cupressiforme and var. plumosum Mart.), which are differentiated by the size, number and form of alar cells and serrate viz. entire leaf tips. Var. subjulaceum is tentatively regarded as alpine variety of Hypnum lacunosum, var, filiforme is regarded as modification based on the oberservation of transitions.
A small collection of bryophytes made during holidays on Réunion in September 2009 revealed 6 species new to the island (Brachymenium acuminatum, B. dicranoides, Bryum lanatum, Campylopus clavatus, Mielichhoferia bryoides and Oxyrhynchium hians). Campylopus crateris has been found for the first time with sporophytes. These new records are incorporated in a new alphabetic list of the mosses of Réunion. Keys for the species for several genera are given.