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Biophysical Characteristics

Rapid assessment of anthropogenic impacts on exposed sandy beaches in Ghana using ghost crabs (Ocypode spp.) as ecological indicators


We applied a rapid assessment methodology to estimate the degree of human impact on exposed sandy beaches in Ghana using ghost crabs as ecological indicators. The use of ghost crab burrow density and size ranges of the burrows as ecological indicators to assess extent of anthropogenic impacts on beaches was explored in this study. For each site, three transects were laid perpendicular to the shoreline over a 100 meter distance at 50 m intervals, i.e., at reference points 0, 50 and 100 meter points. Sampling locations were randomly selected along the three transects using a 1 m x 1 m quadrat. Measurements were done twice weekly for a period of four weeks. The results showed that even though the moderately disturbed beach had higher burrow density than the disturbed beach on the average, the difference is not statistically significant (t-test; p > 0.01). However, the mean burrow diameter at the moderately disturbed site was significantly larger than for the disturbed site (t-test; p < 0.01). We conclude that ghost crab burrow sizes is a better estimator of human impacts on exposed sandy beaches and could be employed as a rapid tool for monitoring the quality of beaches.

 

Name of Author(s):
Denis Worlanyo Aheto1, Cephas Asare2, Emmanuel Abeashi Mensah3 and Joseph Aggrey-Fynn4
Institutional Affiliation:
1,4Department of Fisheries and Aquatic Sciences, School of Biological Sciences, University of Cape Coast; 2Coastal Resources Center (CRC), Adiembra – Sekondi-Takoradi, Ghana; 3Department of Geography and Regional Planning, University of Cape Coast (UCC), Ghana
Type of Publication:
Journal Article
Name of Publisher or Journal:
Momona Ethiopian Journal of Science
Date of Publication:
2011
Number of Pages:
11