Abstract

This study assessed the influence of crab burrows (Macrophthalmus hirtipes) on localized patterns of macrobenthic colonization on a sand flat at 6 m depth in Otago Harbor, New Zealand. 150 m2 of surface sediments were artifically disturbed to simulate a storm and core samples were collected 2, 4, and 30 days later. At each time, samples were randomly collected near and away from crab burrows. A general pattern of high abundances away from burrows was apparent for most common taxa, number of taxa, number of individuals, and dominant polychaete feeding guilds. The differences in abundance near and away from burrows were evident over the three sampling occasions. On the basis of their potential for suspension and transport in the water column during a storm, individuals were allotted to two groups: movable and stationary. Significant trends of increasing abundance over time were found for the movable group, stationary group, and the total number of individuals in samples collected away from burrows. Samples collected near burrows showed a slight but nonsignificant decrease in abundance over time. Changes in the number of taxa over time were not significant, although a similar visual trend as observed for the total number of individuals was apparent. The same taxa were common near and away from burrows, but differences in abundance produced different patterns of colonization. The low abundances around burrows were attributed to the disturbance generated by crabs walking in and out of burrows. Generally the results reported in this study are similar to those which report the influence of ghost shrimps (Callianassa spp.) on macrofauna. This study also demonstrated that patterns of abundance near and away from burrows were maintained during recolonization after a simulated storm disturbance.

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