Distribution of Terebralia palustris (Linnaeus, 1767) and Littoraria subvittata (Reid, 1986) in relation to vertical and horizontal migration
Mwangi, E.M. (2000). Distribution of Terebralia palustris (Linnaeus, 1767) and Littoraria subvittata (Reid, 1986) in relation to vertical and horizontal migration. MSc Thesis. VUB: Brussel. 75 pp.
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Document type: Dissertation
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| Abstract |
The local distribution of Terebralia palustris and Littoraria subvittata was studied. This study describes the migration patterns of the Littoraria subvittata and Terebralia palustris, vertically and horizontally respectively in their habitat. Both gastropod species occur within mangrove forest types, which develop and are restricted to tropical and subtropical regions in sheltered marine or estuarine shores. Several genera of trees are characterized by specific adaptation of pneumatophores and/or viviparous fruits. The distribution of the gastropods is also explained in terms of habitat availability, food availability, geographical replacement due to competition between species and effect resulting from the start of the ebb tide and time of maximum low tide. In this study the Terebralia palustris were found to move horizontally while Littoraria subvittata moved vertically and horizontally. The gastropods movement was correlated to their sizes and grazing activity. T. palustris graze on organic matter found in and on sediments as they move. Littoraria subvittata were found on leaves, and probably feed on algae growing on the leaves. The distribution of T. palustris and L. subvittata was also attributed to predation. There were significant correlations between length and width of the gastropds. The same case applied to their weights. Significant correlations between length of the snails and organic matter content implies that the content of organic matter influenced the growth of the snails. The context of this study therefore shows that the distribution of gastropods is influenced by many factors. |
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