No evidence of genetic structure in a sky island endemic: implications for population persistence under a shrinking thermal niche

Oswald, Krista N; Edwards, Shelley; Lee, Alan T K; Cunningham, Susan J; Smit, Ben

Title: No evidence of genetic structure in a sky island endemic: implications for population persistence under a shrinking thermal niche
Creator: Oswald, Krista N
Creator: Edwards, Shelley
Creator: Lee, Alan T K
Creator: Cunningham, Susan J
Creator: Smit, Ben
Subject: To be catalogued
Date Issued: 2020
Date: 2020
Type: text
Type: article
Identifier: http://hdl.handle.net/10962/461528
Identifier: vital:76210
Identifier: xlink:href="https://www.authorea.com/doi/full/10.22541/au.157901262.24420308"
Description: Mountain habitats physically isolated from one another (“sky islands”) represent a unique system for studying dispersal in seemingly isolated populations. The Cape Fold Belt of southwest South Africa forms a sky island archipelago of high-altitude mountain fynbos of which the Cape Rockjumper Chaetops frenatus is an avian-endemic. Continued contraction of habitat due to increasing temperatures may be causing further isolation of C. frenatus populations beyond their dispersal capacities, resulting in currently declining populations in warmer areas of their habitat. In this study, we sequenced two mitochondrial loci and one nuclear locus of 73 C. frenatus samples from 13 localities representing 8 mountain ranges. We found (1) low overall genetic diversity, (2) no evidence for geographically-based genetic structuring, and (3) no evidence for inbreeding within localities. While this may indicate birds are effectively dispersing, it may also indicate strong selective pressure is being placed on their specific genotype. Haplotype networks suggested that C. frenatus may have experienced a bottleneck or founder effect in their recent genetic past —- a result supported by a significantly negative Tajima’s D value. As the first avian genetic study to arise from a range-restricted species of the Cape Fold Belt sky islands, our results show no evidence that C. frenatus are unable to disperse across inhospitable lowland habitat, and thus may not experience isolation due to climate change. We thus potentially found further support that selective pressure in species with highly specialized habitat niches may have a stronger effect than dispersal limitations.
Format: computer
Format: online resource
Format: application/pdf
Format: 1 online resource (16 pages)
Format: pdf
Publisher: Authorea
Language: English
Relation: Authorea Preprints
Relation: Oswald, K., Edwards, S., Lee, A., Cunningham, S. and Smit, B., 2020. No evidence of genetic structure in a sky island endemic: implications for population persistence under a shrinking thermal niche. Authorea Preprints
Relation: Authorea Preprints 2020
Rights: Publisher
Rights: Use of this resource is governed by the terms and conditions of the Authorea Statement (https://www.authorea.com/)
Rights: Open Access

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Edwards, Shelley (Ms)

Smit, Ben (Dr)

SDG 15. Life On Land

RU Department of Zoology and Entomology

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