| Summary: | 碩士 === 國立中山大學 === 海洋科學系研究所 === 102 === Pontodrilus litoralis is an euryhaline earthworm widely distributed in warm beaches throughout the world. Here, we want to investigate the dispersal mechanisms of the earthworm. Three hypotheses are proposed and tested: 1. Riding the sea current (seagrass and drift wood hypotheses)；2. Transported by human；3. Carried by birds. The earthworm could survive in seawater with wood, but not with seagrass debris. It occurs in beaches without wind breaking woods, or human intervention. The earthworm could not cling to floating seagrasses, nor staying on the bodies of a pigeon. The vertical distribution of the earthworms also make it unlikely for the feet of wading birds to contact them. Based on these results, we find that the drift wood hypothesis is the only dispersal mechanism left unfalsified.
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