An assessment of entomofauna diversity on managed and non-managed beaches : a comparative study

Abstract

Posidonia oceanica is a common and widespread species of seagrass found on all the beaches of the Maltese Islands during the winter period. The banquettes which are formed by the accumulation of this sea grass can range from a few centimetres to a few metres in thickness. It is noted that beach-cast Posidonia oceanica can provide a habitat to a number of invertebrates. During the period between April and September, due to the high influx of tourists and locals which visit the Maltese beaches, the authorities remove the Posidonia oceanica banquettes in fear of the beach’s value declining and due to aesthetic reasons. The aim of this work is to see if the removal of these Posidonia oceanica banquettes has an effect on the insect diversity present on the beaches. After data was collected from two managed and two non-managed beaches across the Malta, the Simpson’s diversity index and Shannon-Weiner’s diversity index were worked out for each beach in order to quantify the insect diversity. The results showed that insect diversity on non-managed beaches was significantly higher than that of beaches which were managed. This proves that there is a negative correlation between the management of beaches i.e. removal of Posidonia oceanica and insect diversity populations. The analysis of the results also showed that each beach had its own unique set of insect assemblages. This shows that even though Malta is a tiny island, there is still an element of compartmentalization between each beach meaning that each individual beach is ecologically important and all of them should be protected.