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Between 1996 and 2006 the vegetation succession in drift sands and in blown-out gravel-rich depressions, located in the nature reserve Hulshorsterzand in the central Netherlands, was studied. Within this Natura 2000 habitat (type 2330: inland dunes with open Corynephorus and Agrostis grasslands) so-called lichen steppes are included, famous for their biodiversity, both in flora (cryptogams), and in fauna. With multivariate analysis, the relation between the primary succession, the species composition of the vegetation and the soil quality was studied in three different biotopes i.e. 1. drift sand, 2. blownout gravel-rich depressions and 3. drift sand after management. With a total of up to 34 species, lichen diversity in the study area appeared to be high. Biotope 1, i.e. the pioneer vegetation with Corynephorus canescens on blowing sand, is rather scarce in lichens. Between 1996 and 2006 green algae, C. canescens and Polytrichum piliferum appeared, with the result that much of the former open drift sand area was covered by pioneer stages of the Spergulo-Corynephoretum. If sand stopped blowing in, a combination of P. piliferum with the neophyte Campylopus introflexus occurred. The terminal stages of lichen succession on drift sand, a vegetation with mainly Festuca ovina s.l., Deschampsia flexuosa and reindeer lichens (Cladonia subgen. Cladina), proved to be rather stable. Since 1996 the lichen steppes occurring in biotope 2 were increasingly grass-encroached. Where some sand was still blowing in, lichen diversity did not change much, but gradually C. introflexus increased. However, without sand blowingin, a decreasing lichen cover and loss of some Red List lichens occurred. In general, in this grass-rich vegetation Calluna vulgaris will germinate and gradually a dry heath might develop. However, where dynamics had stopped and Pinus sylvestris seedlings established, succession to a young forest started. Vegetation change from open sand to lichen-rich vegetation is clearly related to a decrease in pH, an increase in organic matter, in % total N and in % total P. The lichen composition is clearly related to this gradient. The applied restoration measures on steep sand dunes in the eastern area, both of cutting pine trees and removing topsoil down to the mineral soil layer, proved to be successful. The sand kept drifting and the pioneer community thriving, including the lichen Stereocaulon condensatum characteristic of pioneer conditions, while the neophytic moss hardly increased between 1996 and 2006.
The 1996 Chagos Expedition provided the first opportunity to study the archipelago’s lichen flora. Seventeen of the 55 islands were ecologically investigated, some in more detail than others, and lists and representative collections of lichens have been assembled for many of them. In all, 67 taxa have been recorded, 52 to specific level. Although the islands have a low biodiversity for cryptogamic plants, as would be expected in terms of their relatively young age, remoteness and small terrestrial surface areas, those taxa that are present are often found in abundance and play significant ecological roles. There is a good correlation between total lichen biodiversity and island size, despite the fact that Cocos nucifera is such an important substratum for cryptogamic plants and its presence on all islands studied provides a consistently high associated species count. Comparisons of lichen floras for ten island and coastal tropical areas show good correlations (based on the Sörensen Coefficient) within the Indian Ocean as would be expected, but poorer correlations exist within and between Pacific Ocean and neotropical floras. Ranked correlations between Chagos and other floras are in the sequence Maldives > Laing Island > Aldabra > Tuamotu > Pitcairn > N.Mariana & Belize > Guadeloupe > Cook. When coefficients are calculated using only the Physciaceae, different correlations and sequences are derived, but the affinities of the Indian Ocean islands remain strong. However, although the lichen flora of Chagos is characteristic for an Indian Ocean, it is dominated by pantropical species.
Lichen exploration of the Upper Mazaruni District, Guyana yielded 273 species, of which 179 were found for the first time in the Guianas and 13 were as yet undescribed. A list of all taxa encountered is presented, with indications of habitat and distribution in the investigated area as well as first descriptions for the following 7 species: Buellia aptrootii, Byssoloma farkasii, Myriotrema guianense, M. neofrondosum, M. subdactyliferum, Ocellularia astrolucens, and Thelotrema albomaculatum. Mazosia bambusae is recorded for the first time from the Neotropics. The richest areas for lichens appear to be the rocky tablelands with scrub vegetation on top of the lower mountains. The slopes of Mount Roraima are of special interest because they support some montane species which are unlikely to be found elsewhere in the Guianas; otherwise they are less rich in lichens, probably because of the high humidity, which favours bryophyte growth.
New lichens from Africa
(2021)
The following species are described as new to science, mostly based on specimens collected by the first author: Candelariella flavosorediata from Réunion, Chiodecton leprarioides from Réunion, Lecanactis leprarica from Cameroon, Multisporidea nitida, which is a new species and a new, monotypic genus in the Malmideaceae from Réunion, Neoprotoparmelia fuscosorediata from Kenya, Pyrrhospora endaurantia from Kenya, and Tapellaria isidiata from Cameroon.
Several lichen species are reported from the first time from New Guinea, based on material collected by the author in 1995. The following new taxa are described: Crustospathula cartilaginea gen. et spec. nov., Pseudopyrenula serusiauxii spec. nov. and Trypethelium galligenum spec. nov. Psoroma papuana Aptroot & Diederich nom. nov. is proposed as new name for Psoroma pannarioides Aptroot & Diederich.
The Pantanal is a wetland biome in the interior of Brazil. It is known for its rich macrofauna. Botanically, it is relatively species poor, although the marshes have trees and shrubs throughout and there are occasional forested, even somewhat rocky hills. Lichens have received only scant attention so far, but the area is not very species rich (Canêz et al. 2020). We visited the Pantanal several times and collected in different areas. Here we describe four new species, one of which is locally the most common macrolichen, which was found on places elsewhere in the state and in the bordering state of Mato Grosso as well.
Eleven species of lichens are described as new from the Serra do Bodoquena in Mato Grosso do Sul (Brazil): Alyxoria cyanea, Astrothelium ochraceum, Chiodecton xanthonosorediatum, Gyalecta perithecioidea, Gyalecta uniseptata, Pyrenula rubroacutispora, Ramonia xylophila, Synarthonia xanthosarcographoides, Trypethelium aureornatum, Trypethelium endoflavum, and Trypethelium xanthostiolornatum. Around 400 further species are reported, of which 27 are first records for Brazil and 265 are first records for the state.
Six species of lichens are described as new from Santa Catarina and Rio Grande do Sul (Brazil): Astrothelium aureoirregulare Aptroot & Gumboski, Bogoriella xantholateralis Aptroot, Lecanora umbilicatimmersa Aptroot & Spielmann, Lepra lichexanthonorstictica Aptroot, Megalaria flavosorediata Aptroot and Vainionora sorediata Aptroot. Moreover, 28 further species are reported which are first records for Brazil; and a further 166 are first records for Santa Catarina and 104 for Rio Grande do Sul.