AVIAN DISTRIBUTION AND DIVERSITY IN FOREST GAP AND CLOSED CANOPY AREAS OF LOWLAND TROPICAL FOREST

Abstract

An ecological study concerning the effects of treefall gap areas and the association with bird distribution was conducted at the forest area around the Penang Botanical Garden which is encompassed within the Bukit Kerajaan Forest Reserve. A total of 12 study sites were chosen, six sites represent the closed canopy areas and the remaining six represent the gap areas. Bird sampling was conducted using point observation and mist netting methods. Birds detected in gap (229 individuals) areas were significantly higher compared to the closed canopy (147 individuals) areas (?2 = 17.88, df = 1, p < 0.01). The distribution of species found in gap areas differs significantly from closed canopy areas (t-test = 2.487, df = 10, p < 0.05), where gap areas recorded more species than closed canopy areas. The diversity (Shannon-Wiener and Evenness) and species richness (Margalef, Menhinick and True Richness) calculation showed that there are no significant differences between gap areas and closed canopy areas. It is presumed that the size of the gap area is too small to affect the diversity of the birds.

Satu kajian ekologi berkaitan dengan kesan kawasan pokok tumbang dan kaitannya dengan taburan burung telah dijalankan di kawasan hutan di sekeliling Taman Botanikal Pulau Pinang yang termasuk di dalam Kawasan Hutan Simpan Bukit Kerajaan. Sejumlah 12 petak kajian telah dipilih, enam kawasan mewakili kawasan kanopi tertutup dan enam selebihnya mewakili kawasan hutan terbuka atau pokok tumbang. Persampelan burung telah dijalankan dengan kaedah pemerhatian dan persampelan dengan jaring kabut. Burung yang dikesan di kawasan hutan terbuka (229 individu) adalah lebih tinggi secara signifikan berbanding dengan kawasan kanopi tertutup (147 individu) (?² = 17.88, df = 1, p < 0.01). Taburan spesis burung yang dijumpai di kawasan hutan terbuka berbeza secara signifikan dari kawasan kanopi tertutup (Ujian-t = 2.487, df = 10, p < 0.05), di mana kawasan hutan terbuka direkodkan lebih banyak spesies berbanding kawasan kanopi tertutup. Perkiraan Diversiti (Indeks Shannon-Wiener dan Kesamarataan) dan Kekayaan Spesies (Margalef, Menhinick dan Kekayaan Sebenar), menunjukkan tidak terdapat sebarang perbezaan signifikan antara kawasan hutan terbuka dan kawasan kanopi tertutup. Kemungkinan bahawa saiz kawasan hutan terbuka adalah terlalu kecil untuk mempengaruhi nilai diversiti burung di kawasan ini.