Neighbouring Islands (neighbouring + island)

Distribution by Scientific Domains

Selected Abstracts


Summary. In 1977 Grahame Clark suggested that the siting of megalithic tombs along the west coast of Scandinavia reflected the distribution of productive fishing grounds. Unlike the situation in other parts of Europe, these monuments were not associated with agriculture. Opinions have varied over the last quarter century, but enough is now known about changes of sea-level for his interpretation to be investigated on the ground. There seems to have been considerable diversity. On the large island of Örust some of the tombs located near to the sea appear to be associated with small natural enclosures defined by rock outcrops and may have been associated with grazing land. On the neighbouring island of Tjörn, however, the tombs were associated with small islands and important sea channels. During the Bronze Age the same areas included carvings of ships. Recent fieldwork in western Norway suggests that such locations were especially important in a maritime economy. [source]

Storegga tsunami sand in peat below the Tapes beach ridge at Harøy, western Norway, and its possible relation to an early Stone Age settlement

BOREAS, Issue 3 2003
One of the early problems with the Storegga tsunami deposit was how to distinguish it from deposits of the midHolocene (Tapes) transgression. An excavation on Harøy, an island on the outermost western coast of Norway, shows a distinct, clean sand bed embedded in peat and clearly separated from the overlying Tapes beach deposits. This sand bed continues in the peat landwards of the beach ridge for at least 60 m. Radiocarbon dates of the peat show that the sand was deposited some time between 6900 and 7700 yr BP. The sedimentary structures of the bed, the 14C dates, and the fact that this is the only sand bed in the peat, suggest that the sand bed was deposited by a short-lived event, the Storegga tsunami. On the neighbouring island, Fjørtoft, a Stone Age settlement, dated to 7500 yr BP, was discovered in the early 1970s. The settlement was found underneath a sand bed that later had been covered by the Tapes beach ridge deposits. When discovered, the sand covering the settlement was inferred as eolian sand. However, this investigation shows that the Storegga tsunami deposited a widespread sand bed on the land surface around this time with a similar grain size distribution to eolian sand. It is therefore suggested that the sand bed covering this settlement was deposited from the Storegga tsunami. Both the stratigraphy and 14C dates demonstrate that the Tapes transgression maximum was reached well after the Storegga tsunami on Harøy, between 6500 and 6100 yr BP. [source]

Phylogeography of the introduced species Rattus rattus in the western Indian Ocean, with special emphasis on the colonization history of Madagascar

Charlotte Tollenaere
Abstract Aim, To describe the phylogeographic patterns of the black rat, Rattus rattus, from islands in the western Indian Ocean where the species has been introduced (Madagascar and the neighbouring islands of Réunion, Mayotte and Grande Comore), in comparison with the postulated source area (India). Location, Western Indian Ocean: India, Arabian Peninsula, East Africa and the islands of Madagascar, Réunion, Grande Comore and Mayotte. Methods, Mitochondrial DNA (cytochrome b, tRNA and D-loop, 1762 bp) was sequenced for 71 individuals from 11 countries in the western Indian Ocean. A partial D-loop (419 bp) was also sequenced for eight populations from Madagascar (97 individuals), which were analysed in addition to six previously published populations from southern Madagascar. Results, Haplotypes from India and the Arabian Peninsula occupied a basal position in the phylogenetic tree, whereas those from islands were distributed in different monophyletic clusters: Madagascar grouped with Mayotte, while Réunion and Grand Comore were present in two other separate groups. The only exception was one individual from Madagascar (out of 190) carrying a haplotype that clustered with those from Réunion and South Africa. ,Isolation with migration' simulations favoured a model with no recurrent migration between Oman and Madagascar. Mismatch distribution analyses dated the expansion of Malagasy populations on a time-scale compatible with human colonization history. Higher haplotype diversity and older expansion times were found on the east coast of Madagascar compared with the central highlands. Main conclusions, Phylogeographic patterns supported the hypothesis of human-mediated colonization of R. rattus from source populations in either the native area (India) or anciently colonized regions (the Arabian Peninsula) to islands of the western Indian Ocean. Despite their proximity, each island has a distinct colonization history. Independent colonization events may have occurred simultaneously in Madagascar and Grande Comore, whereas Mayotte would have been colonized from Madagascar. Réunion was colonized independently, presumably from Europe. Malagasy populations may have originated from a single successful colonization event, followed by rapid expansion, first in coastal zones and then in the central highlands. The congruence of the observed phylogeographic pattern with human colonization events and pathways supports the potential relevance of the black rat in tracing human history. [source]

Assessing spatial variation in browsing history by means of fraying scars

Bruno Vila
Abstract Aim, We used fraying scars to understand spatial variation in browsing history. Information on browsing history is an essential background in studies on the long-term effect of deer browsing on the flora and fauna and of its variation in space. Location, We focused on two small neighbouring islands of Haida Gwaii (British Columbia, Canada), Reef Island and South-Skedans Island, colonized by introduced black-tailed deer (Odocoileus hemionus sitkensis). Methods, We searched for sites where trees with fraying scars were clustered. We studied the trees that deer selected (species, size) and the characteristics of scars (number, position, size). Using a cross-dating procedure, we dated fraying scars with dendrochronology, obtaining an accurate estimate of the year the scar was formed. Results, On Reef Island, Thuja plicata was the tree species chosen for fraying. On South-Skedans Island, where Thuja plicata is missing, deer chose Salix sp. and Alnus rubra. Deer chose only trees with a circumference of less than 50 cm. About two to three fraying scars were recorded per tree. All of them extended between 30,40 and 70,80 cm from the ground and were between 5 and 6 cm in width. On Reef Island, 95% of the scars were formed during the last 50 years. On South-Skedans Island, 95% were formed over the last 10 years. Age distribution of scars showed a constant increase of the number of scars over time. It indicated that deer had colonized Reef Island 53 years prior to this study but were absent or rare on South-Skedans Island until 13 years prior to this study. Main conclusions, These results indicate different colonization dates and thus different length of browsing histories for the islands studied and provide the historical background necessary to analyse the involvement of deer in the current differences in the flora and fauna observed between islands. [source]

Anzygina, a new genus for some Australasian microleafhopper species formerly placed in the genus Zygina Fieber (Cicadellidae: Typhlocybinae: Erythroneurini)

Murray J Fletcher
Abstract Species of Erythroneurini (Cicadellidae: Typhlocybinae) currently placed in the genus Zygina and found in Australia, New Zealand and some neighbouring islands are transferred to the new genus Anzygina, type species Erythroneura sidnica Kirkaldy, following comparison with the type species of the genus: Typhlocyba nivea Mulsant and Rey. New combinations are Anzygina sidnica (Kirkaldy), Anzygina honiloa (Kirkaldy), Anzygina melanogaster (Kirkaldy) and Anzygina sativae (Evans) from Australia, Anzygina toetoe (Cumber), Anzygina agni (Knight), Anzygina dumbletoni (Ghauri) and Anzygina ramsayi (Knight) from New Zealand, Anzygina zealandica (Myers) from Australia and New Zealand, Anzygina jowettae (Knight) from Norfolk Island and Anzygina medioborealis (Ghauri) from Papua New Guinea. Lectotypes are designated for Erythroneura honiloa Kirkaldy and E. sidnica Kirkaldy. Anzygina billi sp.n. is described from SE Qld, and Anzygina barrattae sp.n. is described from the South Island of New Zealand. A. agni is a new record for Australia and is presumed to be Australian in origin. A. dumbletoni has a distribution which suggests that it also is introduced to New Zealand although its origins are not known. A. ramsayi, A. barrattae and A. toetoe, all of which appear to be New Zealand endemics, show affinity with each other based on aedeagal structure. A key to these species, based on males, is provided. The lack of male syntypes for Erythroneura honiala Kirkaldy and Erythroneura lubra Kirkaldy precludes establishment of their identities relative to other species of the genus, and both names are regarded as having nomen dubium status. Australian species not transferred to Anzygina are Zygina evansi (Ross) and Zygina ipoloa (Kirkaldy), both of which belong elsewhere. [source]