Acoustic Survey on Insectivorous Bats Activity Pattern at Contrasting Elevation in Kubah National Park, Sarawak
Bat monitoring mostly done by using mist nets and harp traps but species that fly high still to be missed out. Additional methods such as acoustic sampling would be able to monitor echolocating bats the tend to avoid the nets. Acoustic sampling gives a better perspective for bat activity monito...
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Main Author: | |
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Format: | Thesis |
Language: | English English |
Published: |
2022
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Subjects: | |
Online Access: | http://ir.unimas.my/id/eprint/40483/1/Thesis%20Msc._Emy%20Ritta%20anak%20Jinggong%20-%2024pages.pdf http://ir.unimas.my/id/eprint/40483/6/Emy%20Ritta%20Ak%20Jinggong%20ft.pdf |
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Summary: | Bat monitoring mostly done by using mist nets and harp traps but species that fly high still
to be missed out. Additional methods such as acoustic sampling would be able to monitor
echolocating bats the tend to avoid the nets. Acoustic sampling gives a better perspective
for bat activity monitoring including study their habitat use. Bats activity may vary
spatially and temporally. In an area with elevational gradient, it is possible to study the
activity of bats simultaneously at different elevation by acoustic monitoring. But first, bat
echolocation call libraries are needed as a reference to identify the calls of free-flying
species. Therefore, the objectives of this study are to build echolocation call library of
Kubah National Park for the purpose of species identification of insectivorous bats through
echolocation call; compare the activity pattern of insectivorous bats at contrasting
elevation by acoustic monitoring; and identify the other factors affecting activity of bats at
contrasting elevation in Kubah National Park. Between November 2018 and February
2019, insectivorous bats were trapped at lower elevation (100-250m a.s.l.) and higher
elevation (700-800m a.s.l.) in Kubah National Park and echolocation calls were recorded
from a total of 68 individuals, representing 13 species from 4 families. The discriminant
function analysis indicated that constant frequency (CF) bats comprised of Families
Hipposideridae and Rhinolophidae could be easily distinguished from their calls recorded
in the detectors. Acoustic survey on their activity was conducted from November 2018 to
August 2019 at lower elevation covered with mixed dipterocarp forests, and at higher
elevation covered with Kerangas forests, scrub forests and lower-montane forest. The
activity of insectivorous bats at higher elevation is higher compared to lower elevation
with 69% of the total bat passes counted from both elevations. In addition, more species
were recorded at higher elevation compared to lower elevation. The result was related with
iv
insect biomass at each elevation but not significantly affected by temperature and moon
phase. This study showed that elevational gradient does affect the activity of bats,
considering the availability of their food abundance and the habitat use. Overall, acoustic
monitoring does provide better way to document species occurrence and ecology
information of insectivorous bats. Further investigations on species-specific in response to
elevations and climate variables are needed and may increase the power of understanding
on factors that influence the bat activity. |
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