Browsing by Author "Davis R"

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    Cultural divergence and morphological variation of isolated remnant populations of the endangered Floreana mockingbird
    (CSIRO Publishing, 2024-07-22) Reyes EMR; Roper MM; Sevilla C; Rueda D; Brunton DH; Smith ANH; Ortiz-Catedral L; Davis R
    Context: Cultural divergence refers to changes over time in behavioural traits. These cultural changes could have important implications for conservation planning, and impact the success of conservation efforts such as translocations. Aims: Here, we investigate the extent, and potential impacts, of cultural divergence in two isolated populations of the Floreana mockingbird (Mimus trifasciatus) on the Galápagos Islands. Methods: Using contemporary recordings of vocalisations we test for spatial vocal differentiation between mockingbird populations. Furthermore, we explore the potential drivers of change using morphological measurements and historical recordings of the species. Key results: We found evidence of spatial and temporal differentiation in vocalisations between the two populations of the Floreana mockingbird. We accurately classified over 75% of the birds to the correct populations based on multivariate measures of audio recordings using canonical analysis of principal coordinates (CAP). We also found significant differences in morphometrics between populations specifically, beak depth was associated with frequency modulation, an acoustic measure that is significantly different between populations. Furthermore, we found evidence of change in the complexity of the vocalisations over a period of 57 years. Conclusions: Cultural divergence was found in the two remaining populations of this endangered species. Factors such as changes in morphology and cultural drift might have been influenced the change in vocalisation across time and populations. Implications: We highlight the importance of considering behavioural factors when planning reintroductions of endangered species where there is a need to minimise the risk of assortative mating so as to maximise genetic diversity.
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    Editorial: Small cetacean conservation: Current challenges and opportunities
    (Frontiers Media S.A., 2022-08-01) Kiszka JJ; Bejder L; Davis R; Harcourt R; Meekan M; Rodriguez DH; Stockin KA; Jessopp M
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    Enhancing the stability of a red organic wine through hydroxytyrosol supplementation at bottling: A time-dependent analysis
    (Elsevier B.V., 2024-09-24) Ceci AT; Darnal A; Poggesi S; Betnga PFT; Longo E; Nicolodi R; Davis R; Walsh M; O'Connor KE; Altieri EA; Trevisan F; Mimmo T; Boselli E
    The effect of the addition of hydroxytyrosol (HT) in a red organic wine (Sangiovese 85 % and Cabernet Sauvignon 15 %) was evaluated. After six months of storage in a concrete tank, the wines were spiked with HT in three different amounts (30, 60, 120 mg/750 mL in wine) and compared with a control bottled wine (no HT addition). The bottled wines were stored at room temperature and were opened after a period of one, three, six, nine and twelve months to perform chemical and sensory analyses (T1, T3, T6, T9, and T12, respectively). Storage time was the factor that most influenced all wines parameters with respect to the different treatments. However, wine added with 60 and 120 mg/750 mL HT had a lower amount of acetic acid than the control at T3 and T6. At T6, the measured HT was negatively correlated with acetic acid (R2 = 0.81), thus suggesting that HT preserved the wine from oxidation. Later, this trend was not confirmed. The content of HT spiked was stable over twelve months of bottle storage; only the endogenous HT, which is naturally present in wine, showed a decrease of 44 % after twelve months of bottle storage. Yellowness (b*) was higher in the 30 mg/750 mL at T9 compared to the other samples. Lightness (L*) showed a decrement of 11 %, while a* (redness) increased by 21 % from T1 to T12. After T6, the wine fortified with 120 mg/750 mL was preferred by the sensory panel; however, it was the only sample to be clustered by the panel at T9 and "red fruits," "spicy", and "astringency" sensory attributes played an important role in this separation.