Browsing by Subject "Biogeography"

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  • Hohnwald, Stefan (2021)
    The northern coast of Honduras is potentially covered with tropical rainforests, reaching from the Caribbean Sea up to the cloud forests of the Pico Bonito summits. Therefore, it was blessed with the megadiverse avifauna of the Central American humid neotropics. Although local bird species have been generally well documented, there are hardly any updates on the biodiversity of northern Honduras. Thus, this study contributes to our knowledge of the natural shift of bird life, following up the Cangrejal River with its different slight land use intensification in the region. Standardized bird records along the valley are analyzed, reaching from the beaches of La Ceiba up to the managed rainforests of El Toncontins in the lower montane rainforests. Nine points were checked over the course of at least 6 days, taking point counts between 16 March and 20 June 2005. A NMDS of the joined nine point-lists elucidates four main groups, namely the beach/city ecosystems, open habitats along the river banks, slightly cleared forests (park landscape), and a mature rainforest. In total, 115 bird species, from 102 genera and 44 families, were found in 2005. As methods are limited, results can represent merely a prodromus of bird composition of neotropical valleys of the Central American isthmus. However, avi-diversity is affected by forest degradation and increasing land-use changes. Since deforestation is still soaring in the region, bird species composition should be monitored, as it will be as dynamic as land use changes in the region.
  • Holopainen, Jari; Helama, Samuli; Väre, Henry (2018)
    Abstract Long records of phenological observations are commonly used as data in global change and palaeoclimate research and to analyse plants' responses to climatic changes. Here we delve into the historical archives of plant phenological observations (1750–1875) compiled and published previously by Professor Adolf Moberg (Imperial Alexander University of Finland). The digitized dataset represents 44,487 observations of 450 different plant species for their 15 different phenological phases made in 193 sites across Finland, and results in 662 different phenological variables. The five most frequently observed variables are the blooming of rye, the sowing of barley, the blooming of bird cherry, the leaf outbreak of birch, and the sowing of oat. The spring and summer observations demonstrate positive relationships between the onset date and the site latitude, this relationship becoming negative for observations made in the autumn. This latitudinal effect is evident in the raw data as demonstrated by the temporal correlations between the unadjusted mean phenological records and the mean latitude of the sites. After the latitudinal effect is removed from the original data such correlations are much reduced and the new set of phenological records based on the adjusted dates can be computed. The resulting mean phenological records correlate negatively and statistically significantly with the mean temperatures from April through July. Linear trends indicate (i) summer onsets having become delayed by more than one week over the full period and (ii) shortening of the growing seasons since 1846. The dataset is made available in an open repository.
  • Kunttu, Panu; Helo, Teppo; Kulju, Matti; Veteli, Pyry; Julkunen, Jari; Miettinen, Otto; Pennanen, Jorma; Moilanen, Aki; Kotiranta, Heikki (2021)
    Biogeographical and ecological knowledge of aphyllophoroid fungi has increased substantially after the publication of the Finnish aphyllophoroid checklist. In this paper, we describe the occurrence and distributions of both aphyllophoroid and heterobasidioid fungi in Finland. We introduce 13 species new to Finland: Hyphoderma lapponicum, Mycostilla vermiformis, Proterochaete adusta, Pseudotomentella alobata, Pseudoxenasma verrucisporum, Sistotrema subtrigonospermum, Spiculogloea minuta, Tomentella botryoides, Tomentella neobourdotii, Tomentella subtestacea, Tomentella subpilosa, Tulasnella anguifera, and Tulasnella interrogans. Proterochaete and Pseudoxenasma are new genera to Finland. We also present the record of Caudicicola gracilis for only the second time globally. Furthermore, we present 115 new records (locations) of 53 rare or seldom collected species. In addition, we report 96 species considered new to a specific subzone of the boreal forest vegetation zone in Finland. The records contain notes on the substrata, and the ecology and distribution of nationally new species and are briefly discussed.
  • Sukhorukov, Alexander P.; Sennikov, Alexander; Veranso-Libalah, Marie Claire; Kushunina, Maria; Nilova, Maya; Heath, Roger; Heath, Alison; Mazei, Yuri; Zaika, Maxim A. (2021)
    Glinus is a small genus of Molluginaceae with 8-10 species mostly distributed in the tropics of the World. Its composition and evolutionary relationships were poorly studied. A new molecular phylogeny constructed here using nuclear (ITS) and chloroplast (rbcL, trnK-matK) markers confirmed the monophyly of the as sister to the remainder of the genus followed by G. oppositifolius. Three other clades are: G. hirtus with G. orygioides; G. radiatus and G. lotoides; the latter is represented by asample from North America, and G. zambesiacus as sister to G. setiflorus + G. lotoides + G. dictamnoides.On the plastid gene tree, G. bainesii + G. oppositifolius form a sister clade to all other Glinus species. The next clade is formed by G. hirtus and G. orygioides followed by G. radiatus plus an American sample of G. lotoides. The next branch comprises G. setiflorus as sister to G. zambesiacus + G. lotoides + G. dictamnoides. Glinus seems to have originated from Africa around the Late Eocene or Early Miocene, with further radiations to Australia and the Americas during the Late Miocene or Late Pliocene. Compared with the previous limited character set used for the diagnostics, we have found ten new morphological and carpological traits distinguishing Glinus members. In both trees based on nuclear and plastid datasets, the major phylogenetic clades cannot be characterized by the peculiar morphological characters. Many shared character states leading to their contrasting pattern in the multivariate analysis model are interpreted as a high homoplasy in the phylogenetically distant species. We paid special attention to the composition of the genus in Sub-Saharan Africa, a region with the greatest species diversity. Our results provide new insight into the taxonomy of Glinus in this region. Glinus lotoides var. virens accepted in many previous works is a synonym of G. dictamnoides that is closely related to G. lotoides based on molecular analysis and morphological characters. The status of the American populations of G. lotoides needs further investigation due to different characters of the specimens from the Old and the New World. Many specimens previously identified as G. lotoides var. virens and as the intermediates G. lotoides x G. oppositifolius belong to G. zambesiacus sp. nov. and G. hirtus comb. nov. (= Mollugo hirta); the latter species is resurrected from synonymy after 200 years of unacceptance. In some African treatments, G. hirtus was known under the invalidly published name G. dahomensis. Glinus zambesiacus is distributed in the southern and eastern parts of tropical Africa, and G. hirtus previously assumed to be endemic to West Africa is indeed a species with a wide distribution across the tropical part of the continent. Glinus microphyllus previously accepted as endemic to West Tropical Africa together with other new synonyms (G. oppositifolius var. lanatus, G. herniarioides, Wycliffea rotundifolia) is considered here as G. oppositifolius var. keenanii comb. nov. (= Mollugo hirta var. keenanii), a variety found across the entire distribution of G. oppositifolius (Australia, Asia, and Africa). The presence of the American G. radiatus in Africa is not confirmed, and all records of this species belong to G. hirtus. M. setiflora, Pharnaceum pentagynum, Wycliffea) as well as a neotype of G. trianthemoides are designated. A new key to the identification of all Glinus species in Sub-Saharan Africa is provided. A checklist is given of all accepted species in this region (G. bainesii, G. hirtus, G. lotoides, G. oppositifolius s.l., G. setiflorus, and G. zambesiacus) with their nomenclature, morphological description and geographical distribution.
  • Clayden, Stephen R.; Ahti, Teuvo; Pino-Bodas, Raquel; Pitcher, Mac; Løfall, Bjørn Petter; McCarthy, John W.; McMullin, R. Troy (2021)
    – Cladonia krogiana, previously known only from Norway and the Czech Republic, is reported here for North America from two localities near the Bay of Fundy, New Brunswick, Canada. It occurs there on open, rocky banks of clear, free-flowing rivers, habitats similar to those in which it has been found in Norway. We also document the occurrence of C. rangiformis in North America, based on collections from two localities on the southwest coast of Conception Bay, on the Avalon Peninsula of the island of Newfoundland, Canada. It is possibly an accidental, but naturalized, introduction in this area, where European settlement began in the early 1600s. A molecular phylogenetic analysis confirmed the identity of one of the Newfoundland specimens. The IGS rDNA haplotype to which it belongs is the same as the most widely distributed haplotype of C. rangiformis in Europe and Macaronesia. Previous reports of C. rangiformis for continental North America are based on misidentifications. A 19th century collection reportedly made on the island of Bermuda, while correctly identified, is of uncertain provenance.
  • Weckström, Kaarina; Roche, Benjamin Redmond; Miettinen, Arto; Krawczyk, Diana; Limoges, Audrey; Juggins, Steve; Ribeiro, Sofia; Heikkilä, Maija (2020)
    A long-term perspective is essential for understanding environmental change. To be able to access the past, environmental archives such as marine and lake sediments that store information in the form of diverse proxy records are used. Whilst many analytical techniques exist to extract the information stored in these proxy records, the critical assessment and refinement of current methods in addition to developing new methods is crucial to improving our understanding. This study aims to improve our knowledge on diatom species used for reconstructing ocean surface conditions, especially temperature and sea ice variability over time. We define the distribution and the relationship to sea surface temperature (SST) and sea ice concentrations (SIC) of the species Fragilariopsis oceanica, Fragilariopsis reginae-jahniae and Fossula arctica using diatom training sets from the northern North Atlantic. We further assess the effect of separating these species compared to grouping them under F. oceanica, as has been done in the past. Our results suggest that while these three species share similarities such as the preference for stratified waters induced by sea ice or glacier meltwater, they also exhibit heterogeneous distributions across the northern North Atlantic, with individual optima for SST and SIC. This also affects quantitative reconstructions based on our data, resulting in lower SST and higher SIC estimates when the species are separated in the surface sediment and down-core diatom assemblages.
  • Heikkinen, Janne Matias; Aalto, Juha; Rantamäki, Olli; Ruikkala, Toni; Soininen, Janne; Pajunen, Virpi (2022)
    Cold subarctic pond ecosystems will be threatened due to the increase in global temperatures. Therefore, it is important to gain more knowledge on how their biota may respond to global warming. The aim of this research was to illustrate the variability in diatom species richness and community composition along environmental gradients in northernmost Finland and Norway and reveal the variables most strongly associated with diatom biodiversity. We also compared diatom biodiversity among different biotope types and placed emphasis on the distribution of rare diatom taxa. A total of 100 subarctic ponds from the Finnish and Norwegian Lapland covering an elevational gradient of 8-887 m above sea level were sampled. A generalised linear model and hierarchical partitioning were used to identify variables associated with diatom species richness. To identify variables associated with diatom community composition, a non-metric multidimensional scaling ordination was performed. Finally, a principal component analysis and permutational multivariate analysis of variance were used for the investigation of environmental and biotic differences among biotope types. Water pH, aluminium concentration, and air temperature best explained the variation in species richness and community composition. Diatom species richness and community composition did not differ among the biotope types, but environmental variables in pine forests differed significantly from other biotope types. Many diatom species occupied the entire elevational gradient, while rare taxa seemed to appear at the ends of the elevational gradient as well around the mid-elevational zone. We found that elevation was not sufficient to explain the variation in diatom species richness and community composition, but diatom biodiversity was shaped by a variety of local-scale environmental variables, some of which are in turn correlated with elevation. Our findings suggest that local abiotic factors and especially water chemistry are important factors in describing the variability in diatom community composition and species richness in subarctic ponds. It seems that the lowest and the highest elevations provide suitable habitats for rare diatom taxa that have unique environmental preferences but some of the rare taxa were also constrained to mid elevations. Our study provides new insights into the role of local abiotic variables in shaping subarctic mountain pond biodiversity. We urge researchers not only to study elevational gradients per se in mountain areas, but also pay special attention to environmental covariates that may play a notable role in maintaining freshwater biodiversity in the subarctic.
  • Migliavacca, Mirco; Musavi, Talie; Mahecha, Miguel D.; Nelson, Jacob A.; Knauer, Jürgen; Baldocchi, Dennis D.; Perez-Priego, Oscar; Christiansen, Rune; Peters, Jonas; Anderson, Karen; Bahn, Michael; Black, T. Andrew; Blanken, Peter D.; Bonal, Damien; Buchmann, Nina; Caldararu, Silvia; Carrara, Arnaud; Carvalhais, Nuno; Cescatti, Alessandro; Chen, Jiquan; Cleverly, Jamie; Cremonese, Edoardo; Desai, Ankur R.; El-Madany, Tarek S.; Farella, Martha M.; Fernandez-Martinez, Marcos; Filippa, Gianluca; Forkel, Matthias; Galvagno, Marta; Gomarasca, Ulisse; Gough, Christopher M.; Göckede, Mathias; Ibrom, Andreas; Ikawa, Hiroki; Janssens, Ivan A.; Jung, Martin; Kattge, Jens; Keenan, Trevor F.; Knohl, Alexander; Kobayashi, Hideki; Kraemer, Guido; Law, Beverly E.; Liddell, Michael J.; Ma, Xuanlong; Mammarella, Ivan; Martini, David; Macfarlane, Craig; Matteucci, Giorgio; Montagnani, Leonardo; Pabon-Moreno, Daniel E.; Panigada, Cinzia; Papale, Dario; Pendall, Elise; Penuelas, Josep; Phillips, Richard P.; Reich, Peter B.; Rossini, Micol; Rotenberg, Eyal; Scott, Russell L.; Stahl, Clement; Weber, Ulrich; Wohlfahrt, Georg; Wolf, Sebastian; Wright, Ian J.; Yakir, Dan; Zaehle, Soenke; Reichstein, Markus; Zaehle, Sönke (2021)
    The leaf economics spectrum(1,2) and the global spectrum of plant forms and functions(3) revealed fundamental axes of variation in plant traits, which represent different ecological strategies that are shaped by the evolutionary development of plant species(2). Ecosystem functions depend on environmental conditions and the traits of species that comprise the ecological communities(4). However, the axes of variation of ecosystem functions are largely unknown, which limits our understanding of how ecosystems respond as a whole to anthropogenic drivers, climate and environmental variability(4,5). Here we derive a set of ecosystem functions(6) from a dataset of surface gas exchange measurements across major terrestrial biomes. We find that most of the variability within ecosystem functions (71.8%) is captured by three key axes. The first axis reflects maximum ecosystem productivity and is mostly explained by vegetation structure. The second axis reflects ecosystem water-use strategies and is jointly explained by variation in vegetation height and climate. The third axis, which represents ecosystem carbon-use efficiency, features a gradient related to aridity, and is explained primarily by variation in vegetation structure. We show that two state-of-the-art land surface models reproduce the first and most important axis of ecosystem functions. However, the models tend to simulate more strongly correlated functions than those observed, which limits their ability to accurately predict the full range of responses to environmental changes in carbon, water and energy cycling in terrestrial ecosystems(7,8).
  • Amesbury, Matthew J.; Booth, Robert K.; Roland, Thomas P.; Bunbury, Joan; Clifford, Michael J.; Charman, Dan J.; Elliot, Suzanne; Finkelstein, Sarah; Garneau, Michelle; Hughes, Paul D. M.; Lamarre, Alexandre; Loisel, Julie; Mackay, Helen; Magnan, Gabriel; Markel, Erin R.; Mitchell, Edward A. D.; Payne, Richard J.; Pelletier, Nicolas; Roe, Helen; Sullivan, Maura E.; Swindles, Graeme T.; Talbot, Julie; van Bellen, Simon; Warner, Barry G. (2018)
    Fossil testate amoeba assemblages have been used to reconstruct peatland palaeohydrology for more than two decades. While transfer function training sets are typically of local-to regional-scale in extent, combining those data to cover broad ecohydrological gradients, from the regional-to continental- and hemispheric-scales, is useful to assess if ecological optima of species vary geographically and therefore may have also varied over time. Continental-scale transfer functions can also maximise modern analogue quality without losing reconstructive skill, providing the opportunity to contextualise understanding of purely statistical outputs with greater insight into the biogeography of organisms. Here, we compiled, at moderate taxonomic resolution, a dataset of nearly 2000 modern surface peatland testate amoeba samples from 137 peatlands throughout North America. We developed transfer functions using four model types, tested them statistically and applied them to independent palaeoenvironmental data. By subdividing the dataset into eco-regions, we examined biogeographical patterns of hydrological optima and species distribution across North America. We combined our new dataset with data from Europe to create a combined transfer function. The performance of our North-American transfer function was equivalent to published models and reconstructions were comparable to those developed using regional training sets. The new model can therefore be used as an effective tool to reconstruct peatland palaeohydrology throughout the North American continent. Some eco-regions exhibited lower taxonomic diversity and some key indicator taxa had restricted ranges. However, these patterns occurred against a background of general cosmopolitanism, at the moderate taxonomic resolution used. Likely biogeographical patterns at higher taxonomic resolution therefore do not affect transfer function performance. Output from the combined North American and European model suggested that any geographical limit of scale beyond which further compilation of peatland testate amoeba data would not be valid has not yet been reached, therefore advocating the potential for a Holarctic synthesis of peatland testate amoeba data. Extending data synthesis to the tropics and the Southern Hemisphere would be more challenging due to higher regional endemism in those areas. (C) 2018 The Authors. Published by Elsevier Ltd.