Variation within and among populations of the endangered Cape Verde warbler: implications for conservation

Batalha, Helena R. (2017) Variation within and among populations of the endangered Cape Verde warbler: implications for conservation. Doctoral thesis, University of East Anglia.

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In this thesis, I investigate variation among the three remaining populations of the Cape Verde warbler Acrocephalus brevipennis, with the aim of defining conservation units and thus informing conservation. I used neutral molecular markers to assess genetic diversity and infer the evolutionary history and adaptive potential of the populations. I found a gradient of diversity from the largest population of Santiago to the smallest one of S. Nicolau, which has been isolated from the populations of Santiago and Fogo for longer than those have been isolated from each other. I measured differences in male song between the populations and whether individuals behaved differently when exposed to songs from the other populations, to determine if song might play a role in reproductive isolation. While there is high intra-population variability in male song, birds do not react differently to songs of males from other populations. I then investigated which habitat traits determined the presence of the bird and whether this differed between the three islands. Evergreen dense vegetation cover predicted the wider areas occupied by the warbler. Structural vegetation traits did not differ between sites used on the islands, but plant species composition did. Finally, I assessed morphological differences between the three populations. I found that males on S. Nicolau have shorter tarsi and longer, narrower bills. These morphological differences match the pattern of neutral genetic divergence, suggesting that the role of drift in driving these differences has not been overridden by selection. Collectively, my results show small but significant divergence between the three populations, particularly between S. Nicolau and the two other populations. This divergence has implications for this bird’s conservation, as the differences observed warrant considering the populations as different management units.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Jackie Webb
Date Deposited: 03 May 2018 14:29
Last Modified: 03 May 2018 14:29

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