On the occurrence of bryophytes and macrolichens in different lowland rain forest types at Mabura Hill, Guyana

A floristic and ecological study of bryophytes and macrolichens in different lowland rain forest types around Mabura Hill, Guyana, South America, yielded 170 species: 52 mosses, 82 liverworts and 36 macrolichens. Lejeuneaceae account for about 30% of the species and are the dominant cryptogamic family of the lowland rain forest. Special attention was paid to the flora of the forest canopy, by using mountaineering techniques. It appeared that 50% of the bryophyte species and 86% of the macrolichens occurred exclusively in the canopy. Dry evergreen 'walaba' forest on white sand is particularly rich in lichens whereas the more humid 'mixed' forest on loamy soil is characterized by a rather rich liverwort flora. More species are exclusive to the mixed forest than to dry evergreen forest due to the 'canopy effect', i.e. the occurrence of xerophytic species in the outer canopy of both dry and humid forests. Furthermore, canopy species have wider vertical distributions on trees in the dry evergreen forest than in the mixed forest, due to the more open canopy foliage of the dry evergreen forest

Foliicolous lichens and their lichenicolous fungi collected during the Smithsonian International Cryptogamic Expedition to Guyana 1996

A total of 233 foliicolous lichen species and 18 lichenicolous fungi are reported from Guyana as a result of the Smithsonian „International Cryptogamic Expedition to Guyana“ 1996. Three lichens and two lichenicolous fungi are new to science: Arthonia grubei sp.n., Badimia subelegans sp.n., Calopadia pauciseptata sp.n., Opegrapha matzeri sp.n. (lichenicolous on Amazonomyces sprucei), and Pyrenidium santessonii sp.n. (lichenicolous on Bacidia psychotriae). The new combination Strigula janeirensis (Bas.: Phylloporina janeirensis; syn.: Raciborskiella janeirensis) is proposed. Apart from Amazonomyces sprucei and Bacidia psychotriae, Arthonia lecythidicola (with the lichenicolous A. pseudopegraphina) and Byssolecania deplanata (with the lichenicolous Opegrapha cf. kalbii) are reported as new hosts for lichenicolous fungi. Arthonia pseudopegraphina growing on A. lecythidicola is the first known case of adelphoparasitism at generic level in foliicolous Arthonia. Arthonia flavoverrucosa, Badimia polillensis, and Byssoloma vezdanum are new records for the Neotropics, and 115 species are new for Guyana, resulting in a total of c. 280 genuine foliicolous species reported for that country, while Porina applanata and P. verruculosa are excluded from its flora. The foliicolous lichen flora of Guyana is representative for the Guianas (Guyana, Suriname, French Guiana) and has great affinities with the Amazon region, while the degree of endemism is low. A characteristic species for this area is Amazonomyces sprucei. Species composition is typical of Neotropical lowland to submontane humid forests, with a dominance of the genera Porina, Strigula, and Mazosia. The table mountain vegetation supports elements of the upper montane forest, such as Echinoplaca fusconitida and Logilvia gilva. Foliicolous lichen diversity is highest in undisturbed lowland to submontane humid forest, much lower in the table mountain vegetation and drastically decreased in semi-open secondary vegetation and the coastal savanna. Species composition in semi-open, disturbed vegetation is similar to that found in the undisturbed forest canopy. Site preferences of foliicolous lichens follow those established by studies in other Neotropical regions like Costa Rica

Bryophyte diversity along an altitudinal gradient in Darién National Park, Panama

A bryophyte inventory along an altitudinal gradient on Cerro Pirre (1200 m), Darién National Park, Panama, demonstrates that the different rain forest types along the gradient (inundatedlowland, hillside-lowland, submontane, montane elfin forest) have very different species assemblages. The montane forest has the largest number of exclusive species and the largest bryophyte biomass. Species richness is greatest in the submontane forest. The bryophyte flora of Cerro Pirre is not exceedingly rich in species owing to the rather low elevation of the mountain and the seasonal climate in the adjacent coastal plain. Nevertheless, the distinct altitudinal diversification and the occurrence of a considerable number of rare hepatic taxa, demonstrate the importance of Darién National Park as an area of plant conservation. Forty hepatic species are reported as new to Panama

New records and additions to the hepatic flora of Uganda 2

82 liverwort taxa are recorded from Uganda, of which 24 are new to the flora of the country. Colura hedbergiana, Colura kilimanjarica and Harpalejeunea fischeri found on Mt. Elgon, were previously known only from their type locality on Mt. Kilimanjaro or on Mt. Karisimbi. A Madagascan-Mascarene species, Plagiochila boryana was also found on Mt. Elgon. Its only known previous locality in continental Africa was Mt. Kilimanjaro

Climate-driven Shifts in Quantity and Seasonality of River Discharge over the past 1000 Years from the Hydrographic Apex of North America

Runoff generated from high elevations is the primary source of freshwater for western North America, yet this critical resource is managed on the basis of short instrumental records that capture an insufficient range of climatic conditions. Here we probe the effects of climate change over the past ~1000 years on river discharge in the upper Mackenzie River system based on paleoenvironmental information from the Peace-Athabasca Delta. The delta landscape responds to hydroclimatic changes with marked variability, while Lake Athabasca level appears to directly monitor overall water availability. The latter fluctuated systematically over the past millennium, with the highest levels occurring in concert with maximum glacier extent during the Little Ice Age, and the lowest during the 11th century, prior to medieval glacier expansion. Recent climate-driven hydrological change appears to be on a trajectory to even lower levels as high-elevation snow and glacier meltwater contributions both continue to decline

Lichens from Mount Kinabalu

286 species of lichenized fungi on Mount Kinabalu are recorded by field survey and investigation of literature records and herbarium material. An annotated catalogue is presented, together with habitat notes, and a list of collectors. The summit area has a saxicolous lichen flora of boreal affinities, while the lower zones are more closely related to other SE Asian mountains. Eleven species appear to be restricted to the mountain, and four new species are described: Phaeographis kinabalensis, Stereocaulon granulans, Pertusaria epitheciifera and Thelotrema subweberi

Additions and corrections to the knowledge of the foliicolous lichen flora of Costa Rica : the genus Fellhanera, with notes on Bacidia pauciseptata

This further contribution to the knowledge of the foliicolous lichen flora of Costa Rica provides a detailed account on the genus Fellhanera. In total, 25 species and five undescribed taxa are treated. Ten species are described as new: Fellhanera angustispora sp.n., F. dictyospora sp.n., F. dispersa sp.n., F. emarginata sp.n., F. pilomarginata sp.n., F. longispora sp.n., F. muhlei sp.n., F. montana sp.n., F. verrucifera sp.n., and F. viridis sp.n. New combinations are F. pauciseptata (R. Sant.) R. Lücking comb.n. [Bas.: Bacidia pauciseptata R. Sant.] and F. rubida (Müll. Arg.) R. Lücking comb.n. [Bas.: Patellaria rubida Müll. Arg.]. F. dominicana (Vain.) Vezda is placed into synonymy with F. fuscatula (Müll. Arg.) Vezda, whose type has 7-septate ascospores, and the name F. subfuscatula R. Lücking sp.n. is introduced for the taxon with 5-septate ascospores formerly known as F. fuscatula. F. misionensis Ferraro & R. Lücking ined. and F. sublecanorina (Nyl.) Vezda are reported for the first time from Costa Rica. The formerly invalidly published names F. farinosa nom. nud. and F. pilosa nom. nud. are considered to be synonyms of F. fuscatula (Müll. Arg.) Vezda and F. rhapidophylli (Rehm) Vezda, respectively. Specimens identified as F. tuckeri nom. nud. belong to F. rhapidophylli as well. F. buxi is excluded from the foliicolous lichen flora of Costa Rica. A keys is provided to the complex group of species of Fellhanera with brownish apothecia and 3-septate ascospores. Infrageneric relationships within Fellhanera are briefly discussed, and notes on the ecology of the species are provided.La presente contribución al conocimiento de la líquenoflora foliícola de Costa Rica trata en detalle el género Fellhanera, incluyendo 25 especies y otros cinco taxa aún no descritos hasta la fecha. Se describen diez especies nuevas: Fellhanera angustispora sp.n., F. dictyospora sp.n., F. dispersa sp.n., F. emarginata sp.n., F. pilomarginata sp.n., F. longispora sp.n., F. muhlei sp.n., F. montana sp.n., F. verrucifera sp.n., y F. viridis sp.n., además de las nuevas combinaciones F. pauciseptata (R. Sant.) R. Lücking comb.n. [Bas.: Bacidia pauciseptata R. Sant.] y Fellhanera rubida (Müll. Arg.) R. Lücking comb.n. [Bas.: Patellaria rubida Müll. Arg.]. F. dominicana (Vain.) Vezda es puesta en sinonimía con F. fuscatula (Müll. Arg.) Vezda, cuyo material tipo tiene esporas 7-septadas, y el nombre F. subfuscatula R. Lücking sp.n. es introducido para el taxon con esporas 5-septadas, hasta ahora conocido como F. fuscatula. F. misionensis Ferraro & R. Lücking ined. y F. sublecanorina (Nyl.) Vezda son comunicados por primera vez de Costa Rica. Los nombres F. farinosa nom. nud. and F. pilosa nom. nud., invalidamente publicadas por el autor en una publicación anterior, son considerados como sinónimos de F. fuscatula (Müll. Arg.) Vezda y F. rhapidophylli (Rehm) Vezda, respectivamente. Especimenes entonces identificados como F. tuckeri nom. nud. actualmente pertenecen a F. rhapidophylli; igualmente, F. buxi Vezda & Vivant es excluida de la líquenoflora foliícola de Costa Rica. Se presenta una clave para el dificil grupo de especies de Fellhanera con apotecios marrones y esporas 3-septadas. Finalmente, se discutan las relaciones infragenericas dentro del género Fellhanera, y se dan notas sobre la ecología de las especies

Scientific results of the Bryotrop expedition to Zaire and Rwanda : 7., life strategies of epiphytic bryophytes from tropical lowland and montane forests, ericaceous woodlands and the Dendrosenecio subpáramo of the eastern Congo basin and the adjacent mountains (Parc National de Kahuzi-Biega/Zaire, Forêt de Nyungwe/Rwanda)

Life strategies of epiphytic bryophytes are studied along an altitudinal gradient from the eastern Congo basin (tropical lowland zone) to the mountains of the East-African graben (tropical subalpine/alpine Zone; BRYOTROP III-transect). Three strategies, Colonists, Perennial shuttle species and Perennial stayers can be observed, which are further subdivided according to their reproduction tactic (high sexual reproductive effort, high asexual reproductive effort, moderately or low sexual and asexual reproductive effort). Of these, only taxa with a long life span (perennials) are of importance, indicating the unchanging and constant ecological conditions and long-lasting microsites, provided by the epiphytic habitats. The basis for the life strategy pattern analysis along the altitudinal gradient were plant sociological investigations and the determination of the mean percentage cover values for the different life strategy categories. By this, the distribution and occurrence of the different strategies within the communities and the altitudinal zones can be shown

Ecosystem recharge by volcanic dust drives broad-scale variation in bird abundance

Across the globe, deserts and volcanic eruptions produce large volumes of atmospheric dust, and the amount of dust is predicted to increase with global warming. The effects of long-distance airborne dust inputs on ecosystem productivity are potentially far-reaching but have primarily been measured in soil and plants. Airborne dust could also drive distribution and abundance at higher trophic levels, but opportunities to explore these relationships are rare. Here we use Iceland's steep dust deposition gradients to assess the influence of dust on the distribution and abundance of internationally important ground-nesting bird populations. Surveys of the abundance of breeding birds at 729 locations throughout lowland Iceland were used to explore the influence of dust deposition on bird abundance in agricultural, dry, and wet habitats. Dust deposition had a strong positive effect on bird abundance across Iceland in dry and wet habitats, but not in agricultural land where nutrient levels are managed. The abundance of breeding waders, the dominant group of terrestrial birds in Iceland, tripled on average between the lowest and highest dust deposition classes in both wet and dry habitats. The deposition and redistribution of volcanic materials can have powerful impacts in terrestrial ecosystems and can be a major driver of the abundance of higher trophic-level organisms at broad spatial scales. The impacts of volcanic ash deposition during eruptions and subsequent redistribution of unstable volcanic materials are strong enough to override effects of underlying variation in organic matter and clay content on ecosystem fertility. Global rates of atmospheric dust deposition are likely to increase with increasing desertification and glacier retreat, and this study demonstrates that the effects on ecosystems are likely to be far-reaching, both in terms of spatial scales and ecosystem components

Scientific results of the Bryotrop expedition to Zaire and Rwanda : 3., photosynthetic gas exchange of bryophytes from different forest types in eastern Central Africa.

During the BRYOTROP-Expedition to Zaire and Rwanda bryophytes were collected from a rainforest habitat at 800 m a.s.l. and from bamboo forest and tree-heath environments between 2200 and 3200 m. The microclimates influencing the mosses are different at the altitudinally separated locations. Conditions are rather constant with 24 °C, 100 % rel. hum. and PAR below 100 μmol photons m-2 sec-1 at the lowland station, rather versatile in the mountains with six times higher daily sums of PAR, temperatures between 10 and 25 °C and relative humidities between 60 and 1oo %. In the bamboo forest epiphytic mosses dry out during the day to less than 70 % of their water content, but regain saturation from the vapor-saturated air during night. Bryophyte photosynthesis and respiration were studied by Warburg manometry with moisture saturated samples. Temperature curves of gas exchange peaked between 22 and 30 °C. Optima of the lowland species were somewhat higher than those from samples collected at the mountain sites. Habitat separation of characteristics of photosynthesis was more pronounced with respect to light responses. Saturation gas exchange rates were reached by all species still below 400 μmol photons m-2 sec-1. But the slopes of the curves in the low-light range were distinctly steeper, and the light compensation points smaller in the lowland than in the highland species (compensation points of the former: 3 - 12 μmol photons m-2 sec-1, of the latter: 8 - 20 μmol photons m-2 sec-1). It is emphasized that bryophytes in the rainforest understory experience extremely high ambient C02 concentrations near the floor. This, their low light requirements for photosynthesis, and the permanently optimal temperature and humidity conditions for maximal carbon gain enable them to live successfully, but with less biomass development in this dark and damp environment. By contrast, bryophytes from the bamboo forest and tree-heath environments can utilize light conditions combined with variable temperatures and humidities similarly as species from extratropical vegetation types