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Coastal Lowlands (coastal + lowland)
Selected AbstractsBasidiomycetes and larger Ascomycetes from YemenFEDDES REPERTORIUM, Issue 7-8 2004H. Kreisel Prof. Dr. From the territory of Yemen 39 taxa of larger fungi (macromycetes: 36 Basidiomycetes and three Ascomycetes), including former records in literature, are enumerated and annotated. 22 taxa have been collected in recent times; 16 of them are first records from Yemen. Actually eight taxa are known from the highlands, 16 taxa from the coastal lowland, and 15 taxa (only very old records) from the island Socotra. Constituents of the macromycete flora of Yemen are species of south-temperate to mediterranean distribution (mainly represented in the highlands), species of subtropical to tropical distribution (mainly represented in the lowlands) and nearly cosmopolitic elements. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Basidiomyceten und größere Ascomyceten aus Jemen Aus dem Territorium des Jemen werden, unter Einbeziehung früher publizierter Funde, 39 Taxa von Großpilzen (36 Basidiomycetes und drei Ascomycetes) aufgezählt. 22 Taxa wurden in neuerer Zeit gesammelt; 16 werden hier erstmalig für Jemen angezeigt. Aus dem Hochland sind nunmehr acht Taxa, aus dem Küstentiefland 16 Taxa und von der Insel Socotra (von hier nur sehr alte Angaben) 15 Taxa Macromyceten bekannt. Bestandteile der Pilzflora des Jemen sind südlich-temperate (vorwiegend im Hochland nachgewiesene), subtropisch-tropische (im Küstentiefland nachgewiesene) und annähernd kosmopolitische Arten. [source] The deglaciation of Clyde Inlet, northeastern Baffin Island, Arctic Canada,JOURNAL OF QUATERNARY SCIENCE, Issue 3 2007Jason P. Briner Abstract The behaviour of ice sheets as they retreated from their Last Glacial Maximum (LGM) positions provides insights into Lateglacial and early Holocene ice-sheet dynamics and climate change. The pattern of deglaciation of the Laurentide Ice Sheet (LIS) in arctic fiord landscapes can now be well dated using cosmogenic exposure dating. We use cosmogenic exposure and radiocarbon ages to constrain the deglaciation history of Clyde Inlet, a 120,km long fiord on northeastern Baffin Island. The LIS reached the continental shelf during the LGM, retreated from the coastal lowlands by 12.5,±,0.7,ka (n,=,3), and from the fiord mouth by 11.7,±,2.2,ka (n,=,4). Rapid retreat from the outer fiord occurred 10.3,±,1.3,ka (n,=,6), with the terminus reaching the inner fiord shortly after 9.4,ka (n,=,2), where several moraine systems were deposited between ca. 9.4 and ca. 8.4,ka. These moraines represent fluctuations of the LIS during the warmest summers since the last interglaciation, and this suggests that the ice sheet was responding to increased snowfall. Before retreating from the head of Clyde Inlet, the LIS margin fluctuated at least twice between ca. 7.9 and ca. 8.5,ka, possibly in response to the 8.2,ka cold event. Copyright © 2006 John Wiley & Sons, Ltd. [source] mtDNA perspective of chromosomal diversification and hybridization in Peters' tent-making bat (Uroderma bilobatum: Phyllostomidae)MOLECULAR ECOLOGY, Issue 11 2003Federico G. Hoffmann Abstract We compared sequence variation in the complete mitochondrial cytochrome -b gene with chromosomal and geographical variation for specimens of Peters' tent-making bat (Uroderma bilobatum). Three different chromosomal races have been described in this species: a 2n = 42 race from South America east of the Andes, a 2n = 44 from NW Central America and 2n = 38 from the rest of Central America and NW South America. The deepest nodes in the tree were found within the South American race (42 race), which is consistent with a longer history of this race. Average distance among races ranged from 2.5 to 2.9%, with the highest amount of intraracial variation found within the 2n = 42 race (1.7%), intermediate values within the 2n = 38 race (0.9%) and lowest within the 2n = 44 race (0.5%). Variation among chromosomal races accounted for over 55% of molecular variance, whereas variation among populations within races accounted for 6%. The 2n = 38 and 2n = 44 races hybridize in the coastal lowlands of Honduras, near the Gulf of Fonseca. Introgression between these two races is low (two introgressed individuals in 45 examined). Clinal variation across the hybrid zone for the cytochrome -b of U. bilobatum, is similar to clinal variation reported for chromosomes and isozymes of this species. Mismatch distribution analyses suggests that geographical isolation and karyological changes have interplayed in a synergistic fashion. Fixation of the alternative chromosomal rearrangements in geographical isolation and secondary contact is the most likely mechanism accounting for the hybrid zone between the 2n = 38 and 2n = 44 races. If a molecular clock is assumed, with rates ranging from 2.3 to 5.0% per million years, then isolation between these races occurred within the last million years, implying a relatively recent origin of the extant diversity in Uroderma bilobatum. None the less, the three chromosomal races probably represent three different biological species. [source] Faunal migration in late-glacial central Italy: implications for human resource exploitation,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2008Maura Pellegrini The hunter-gatherer transhumance model presents foragers as specialised hunters of migratory ungulates, which moved seasonally between coastal lowlands and interior uplands. We studied six animal teeth of horse (Equus hydruntinus) and red deer (Cervus elaphus) from four different archaeological sites: the Grotta di Vado all'Arancio, Grotta di Settecannelle, Grotta Polesini and Grotta di Pozzo, in central Italy to test whether the migratory patterns and seasonal variations recorded in their teeth were consistent with expectations of the transhumance model for this region during the late Upper Palaeolithic. Sequential sub-samples of enamel were analysed from each tooth for oxygen, carbon and strontium isotope ratios to reconstruct mobility and yearly seasonal variations. The results show little evidence that these animals were moving over different geological terrains throughout the year, although small variations in Sr isotope ratios and concentrations were detected that corresponded to probable seasonal variations as shown by variability in oxygen isotope sequences. The results do, however, demonstrate that Cervus elaphus and Equus hydruntinus had different ranging behaviours, with the former moving over wider areas than the latter. This methodology produces results appropriate to assess animal migratory behaviour and, in turn, to test the consistency of proposed models of hunter-gatherer subsistence and mobility strategies. Copyright © 2008 John Wiley & Sons, Ltd. [source] Variation in the impact of exotic grasses on native plant composition in relation to fire across an elevation gradient in HawaiiAUSTRAL ECOLOGY, Issue 5 2000Carla M. D'Antonio Abstract The impact that an exotic species can have on the composition of the community it enters is a function of its abundance, its particular species traits and characteristics of the recipient community. In this study we examined species composition in 14 sites burned in fires fuelled by non-indigenous C4 grasses in Hawaii Volcanoes National Park, Hawaii. We considered fire intensity, time since fire, climatic zone of site, unburned grass cover, unburned native cover and identity of the most abundant exotic grass in the adjacent unburned site as potential predictor variables of the impact of fire upon native species. We found that climatic zone was the single best variable for explaining variation in native cover among burned sites and between burned and unburned pairs. Fire in the eastern coastal lowlands had a very small effect on native plant cover and often stimulated native species regeneration, whereas fire in the seasonal submontane zone consistently caused a decline in native species cover and almost no species were fire tolerant. The dominant shrub, Styphelia tameiameia, in particular was fire intolerant. The number of years since fire, fire intensity and native cover in reference sites were not significantly correlated with native species cover in burned sites. The particular species of grass that carried the fire did however, have a significant effect on native species recovery. Where the African grass Melinis minutiflora was a dominant or codominant species, fire impacts were more severe than where it was absent regardless of climate zone. Overall, the impacts of exotic grass-fuelled fires on native species composition and cover in seasonally dry Hawaiian ecosystems was context specific. This specificity is best explained by differences between the climatic zones in which fire occurred. Elevation was the main physical variable that differed among the climatic zones and it alone could explain a large percentage of the variation in native cover among sites. Rainfall, by contrast, did not vary systematically with elevation. Elevation is associated with differences in composition of the native species assemblages. In the coastal lowlands, the native grass Heteropogon contortus, was largely responsible for positive changes in native cover after fire although other native species also increased. Like the exotic grasses, this species is a perennial C4 grass. It is lacking in the submontane zone and there are no comparable native species there and almost all native species in the submontane zone were reduced by fire. The lack of fire tolerant species in the submontane zone thus clearly contributes to the devastating impact of fire upon native cover there. [source] Rethinking Late Weichselian ice-sheet dynamics in coastal NW SvalbardBOREAS, Issue 1 2005JON Y. LANDVIK New marine geological evidence provides a better understanding of ice-sheet dynamics along the western margin of the last Svalbard/Barents Sea Ice Sheet. A suite of glacial sediments in the Kongsfjordrenna cross-shelf trough can be traced southwards to the shelf west of Prins Karls Forland. A prominent moraine system on the shelf shows minimum Late Weichselian ice extent, indicating that glacial ice also covered the coastal lowlands of northwest Svalbard. Our results suggest that the cross-shelf trough was filled by a fast-flowing ice stream, with sharp boundaries to dynamically less active ice on the adjacent shelves and strandflats. The latter glacial mode favoured the preservation of older geological records adjacent to the main pathway of the Kongsfjorden glacial system. We suggest that the same model may apply to the Late Weichselian glacier drainage along other fjords of northwest Svalbard, as well as the western margin of the Barents Ice Sheet. Such differences in glacier regime may explain the apparent contradictions between the marine and land geological record, and may also serve as a model for glaciation dynamics in other fjord regions. [source] Configuration, history and impact of the Norwegian Channel Ice StreamBOREAS, Issue 1 2003Hans Petter Sejrup The Norwegian Channel between Skagerrak, in the southeast, and the continental margin of the northern North Sea, in the northwest, is the result of processes related to repeated ice stream activity through the last 1.1 m yr. In such periods the Skagerrak Trough (700 m deep) has acted as a confluence area for glacial ice from southeastern Norway, southern Sweden and parts of the Baltic. Possibly related to the threshold in the Norwegian Channel off Jæren (250 m deep), the ice stream, on a number of occasions over the last 400 ka, inundated the coastal lowlands and left an imprint of NW-oriented ice directional features (drumlins, stone orientations in tills and striations). Marine interstadial sediments found up to 200 m a.s.l. on Jæren have been suggested to reflect glacial isostasy related to the Norwegian Channel Ice Stream (NCIS). In the channel itself, the ice stream activity is evidenced by mega-scale glacial lineations on till surfaces. As a result of subsidence, the most complete sedimentary records of early phases of the NCIS are preserved close to the continental margin in the North Sea Fan region. The strongest evidence for ice stream erosion during the last glacial phase is found in the Skagerrak. On the continental slope the ice stream activity is evidenced by the large North Sea Fan, which is mainly a result of deposition of glacial-fed debris flows. Northwards of the North Sea Fan, rapid deposition of meltwater plume deposits, possibly related to the NCIS, is detected as far north as the Vøring Plateau. The NCIS system offers a unique possibility to study ice stream related processes and the impact the ice stream development had on open ocean sedimentation and circulation. [source] | ||||||||||