Bird community structure of small islands: a case study on the Pahawang Island, Lampung Province,&amp;nbsp;Indonesia

Dian Iswandaru,Trio Santoso,Gunardi Djoko Winarno,Rahmat Safe’I,Dini Zulfiani,Indra Gumay Febryano,Hari Kaskoyo,Arief Darmawan,Rudi Hilmanto

doi:10.3897/silvabalcanica.21.e56108

Abstract

Small islands are extremely vulnerable to ecosystem disturbances. One of the common factors im-pacting on island ecosystems is the rise of tourism activity and the associated conversion of man-grove forest&rsquo;s function into tourism&rsquo;s supporting facility. Those changes will ultimately affect the diversity of bird species inhabiting the island. &nbsp;Therefore, this study aimed to analyse the structure of a bird community in the mangrove forests of the Pahawang Island. The study used the transect method with tracking implemented. The obtained data were analysed using the Shannon-Wienner diversity index. We recorded 28 species from 21 families. Out of 21 families, Columbidae had the highest number of species (three species). Seven feeding guilds were observed during the present study, the maximum number of species belonged to the insectivore group and the minimum &ndash; to the nectarivore and omnivore (1 species each) guilds. Based on the abundance rank, the most abundant species was the cave swiftlet (Collochalia linchi). Three of the recorded species are listed in the cat-egory &ldquo;Protected&rdquo; according to the Indonesia Law: the brahminy kite (Haliastur indus), sunda pied fantail (Rhipidura javanica), and the black-naped tern (Sterna sumatrana). All bird species that have been recorded during the present study is classified as &ldquo;Least Concern&rdquo; in the IUCN Red List. The values of the Shannon-Wienner index suggest neither high nor low diversity (H&rsquo; = 2.55). Mangrove&nbsp;forest ecosystems, including the mudflat on the Pahawang Island, are important supporting popula-tions of wild birds through providing foraging, roosting and nesting sites.&nbsp;

Highlights

Islands accommodate an important part of global biodiversity
This study aimed to analyse the structure of the bird community in the mangrove forest on the Pahawang Island, following a recent degradation of mangrove forests due to increased human activities that may pose a threat to the ecosystem of this small island
Birds are included in the category of terrestrial fauna occupying the top of the mangrove trees and several species occupying the bottom of the mangrove trees

Summary

Introduction

The house more than 10% of all mammal and bird species, representing only less than 2% of the Earth’s land surface (Del Hoyo et al, 1992-1993; Alcover et al, 1998; Clements, 2000; Hahn et al, 2016) Because they are geographically isolated, the islands have been identified as centres of speciation, owing to the fact that a large number of their native fauna consists of endemic species (Beierkuhnlein et al, 2011; Hahn et al, 2016). The ecosystems of the small island often have high levels of biodiversity and endemicity but are very vulnerable because of the small population size of the species and the low genetic variation (Paulay, 1994; Polman et al, 2016). This suggests that the small island ecosystems are vulnerable when compared to terrestrial ecosystems (Fisher, 2004)

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