Cite as:
Ginal, P. (2017): <b>Acoustic indices do not reflect avian diversity in high-diverse tropical rainforests in Ecuador</b> Philipps-Universit&auml;t Marburg, <i>master thesis</i>

Resource Description

Title: Acoustic indices do not reflect avian diversity in high-diverse tropical rainforests in Ecuador
FOR816dw ID: 1556
Publication Date: 2017-02-12
License and Usage Rights: PAK 823-825 data user agreement. (
Resource Owner(s):
Individual: Philipp Ginal
Biodiversity monitoring is a global need due to environmental degradation and climate change. Birds are<br/> often monitored indicators for environmental health because they are easy assessable, fast reacting species,<br/> which supply important ecosystem services. But conventional biodiversity monitoring can be timeconsuming,<br/> invasive<br/> and<br/> it<br/> often<br/> needs<br/> trained<br/> specialists,<br/> thus<br/> appropriate<br/> alternatives,<br/> especially<br/> for<br/> largescale<br/> assessments,<br/> like<br/> acoustic<br/> monitoring<br/> are<br/> needed.<br/> While<br/> numerous<br/> acoustic<br/> indices<br/> were<br/> generated<br/> no<br/> studies<br/> occur<br/> about<br/> their<br/> ability<br/> to<br/> reflect<br/> conventional<br/> alpha-diversity<br/> measures<br/> such<br/> as<br/> species<br/> richness,<br/> abundance,<br/> diversity or evenness under complex conditions like a gradient of elevation and degradation.<br/> We choose bird communities along an elevation gradient in natural and degraded rainforests in a highdiverse<br/> region in the Ecuadorian Andes to investigate the association among five conventional (total<br/> abundance, species richness, Shannon Index, evenness, Gini Index) and three acoustic (Acoustic Diversity<br/> Index [ADI], Bioacoustic Index [BI], Acoustic Evenness Index [AEI]) alpha-diversity measures. Furthermore,<br/> we investigated the influence of higher resolutions (FFT window size, frequency band size) on the acoustic<br/> indices. Further, we tested a new acoustic beta-diversity measure. With help of multivariate analyzes we<br/> found acoustic diversity measures were not significantly correlated with conventional diversity measures in<br/> high-diverse rainforests. The acoustic indices were correlated between another. The values of the acoustic<br/> indices increased with higher resolutions and were strongly positively correlated with their next higher<br/> resolution. The NMDS of the conventionally assessed bird communities resulted an elevation gradient and a<br/> distinct separation between degraded and natural forest communities. The NMDS of the acoustically<br/> assessed bird communities resulted no distinct gradients. The conventional and acoustic alpha-diversity<br/> measures were not significantly associated with the elevation or habitat type. ADI, BI and AEI seem not<br/> appropriate to reflect conventional diversity measures in high-diverse ecosystems, but BI can reflect avian<br/> abundance in less diverse ecosystems. Avian acoustic activity was driven by noisy species and not by<br/> species richness or abundance. Higher resolutions of the acoustic indices did not resolute acoustic activity<br/> more exactly in this case, thus for communities where birds with long or complex calls (relevant for BI) or<br/> narrow frequency ranges (relevant for ADI/AEI) are not dominating the acoustic activity the default resolutions of the acoustic indices seem sufficient. Acoustic beta-diversity assessment seems problematic<br/> because the analyzes of frequencies does not reflect species turnover among communities due to the<br/> reason that several species can occupy the same frequencies with their calls.
Additional Infos:
Author: Philipp Ginal
| beta diversity | species richness | abundance | Alpha diversity | Shannon diversity | soundscape | Acoustic Diversity Index | Bioacustic Index | Acoustic Evenness Index | Gini Index | resolution |
Literature type specific fields:
Degree: master
Degree Institution: Philipps-Universit├Ąt Marburg
Total Pages: 20
Metadata Provider:
Individual: Yvonne Tiede
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