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Community dynamics of insular biotas in space and time

the Dahlak archipelago, Red Sea, Eritrea and east African coastal forests

Azeria, Ermias Tesfamichael (2004). Community dynamics of insular biotas in space and time. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Silvestria, 1401-6230 ; 311
ISBN 91-576-6545-1
[Doctoral thesis]

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The various features determining species distributions remain enigmatic in ecology. This thesis deals with the spatial and temporal dynamics of land birds on the islands of the Dahlak archipelago, the Red Sea, and of mammals, birds and reptiles among the forest fragments of the archipelago-like east African coastal forest. The bird species richness on the islands of the Dahlak archipelago depended on area, isolation and extent of habitat. Similarly, species richness of the east African forest fragments was related to area, habitat diversity and isolation but the importance of each factor varied among taxa as well as among generalists and specialists. For example, area influenced species richness of most categories except specialist mammals and reptiles, habitat diversity was more important for forest specialists than generalists, and isolation was important only for birds. In both study areas, similarity in bird species composition decreased with increasing distances among isolates suggesting that dispersal from source pools and among isolates facilitate re-colonization. The nested community structure, i.e. species composition of species−poor communities are a subset of species−rich communities, of birds in the Dahlak archipelago depended on area and the distribution of a few habitats. Similarities in community patterns and cooccurrence patterns, at both community and species levels, were mainly related to habitat preferences and corresponding distributions of habitats as well as inter-island distances. Also, the distributional patterns suggest that predator-prey interactions can be a determinant of the spatial distribution of, at least, the prey. There was no evidence of competitive exclusion. The nested structure on the islands of the Dahlak archipelago remained fairly stable over a period of 35 years even in this arid region. The turnover dynamics were broadly predictable from the nested pattern but not always consistent with other expectations from nested community structure. Taken together my results show that mechanisms on varying spatial and temporal scales act on species distributions, and that the influence may vary among taxa mainly depending on dispersal ability. In the case of conservation, comprehensive strategies accounting for these variations are needed.

Authors/Creators:Azeria, Ermias Tesfamichael
Title:Community dynamics of insular biotas in space and time
Subtitle:the Dahlak archipelago, Red Sea, Eritrea and east African coastal forests
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Silvestria
Year of publishing :May 2004
Number of Pages:38
ALLI. Azeria, E.T. 2004. Terrestrial bird community patterns on the coralline islands of Dahlak Archipelago, Red Sea, Eritrea. Global Ecology and Biogeography, 13 (2): 177-187. II. Azeria, E.T., Pärt, T. & Wiklund, C.G. Explaining patterns of insular land bird community structure: species-habitat and species-species associations. (Manuscript) III. Azeria, E.T., Carlson, A., Pärt, T. & Wiklund, C.G. Temporal dynamics and nestedness of an oceanic island bird fauna. (Manuscript) IV. Azeria, E.T., Sanmartín, I., Ås, S. & Carlson, A. Patterns of vertebrate distribution in the East African coastal forests: a comparative analysis of birds, mammals, and reptiles (Manuscript)
Place of Publication:Uppsala
ISBN for printed version:91-576-6545-1
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P01 Nature conservation and land resources
L Animal production > L20 Animal ecology
Subjects:Not in use, please see Agris categories
Agrovoc terms:biogeography, islands, habitats, spatial distribution, birds, mammals, reptiles, east africa, red sea
Keywords:Community assembly, habitat specialization, inter-island dispersal, island biogeography, nestedness, species co-occurrence
Permanent URL:
ID Code:535
Department:(NL, NJ) > Institutionen för naturvårdsbiologi (fr.o.m. 970101)
Deposited By: Ermias Azeria
Deposited On:12 May 2004 00:00
Metadata Last Modified:02 Dec 2014 10:05

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